A multi-battery cluster parallel energy storage system control circuit and a control method thereof

Abstract

The application discloses a kind of multi-cell cluster parallel energy storage system control circuit and its control method, wherein, energy storage battery cluster parallel control circuit includes: N energy storage battery cluster, wherein N is positive integer;N energy storage battery cluster management module, the energy storage battery cluster management module is one-to-one with the energy storage battery cluster, and the energy storage battery cluster management module is used to collect the state information of its corresponding energy storage battery cluster;System management controller is used to issue control signal according to the summary N energy storage battery cluster state information, to make the battery cluster management module control its corresponding energy storage battery cluster;DC-DC converter is used to perform charging / discharging work according to the control signal.This circuit can be realized in energy storage system internal energy storage battery cluster between by the way of energy transmission realizes mutual complement of energy and finally reaches the consistency of state, prevents the high surge circulating current impact between parallel battery cluster, ensures the safety and reliability of multi-cell cluster parallel.

Description

Technical Field

[0001] This application belongs to the field of power system control technology, specifically relating to a control circuit and control method for an energy storage system with multiple battery clusters connected in parallel. Background Technology

[0002] Energy storage is a crucial supporting technology for smart grids and energy systems with a high proportion of renewable energy. It is an important component of my country's strategic emerging industries, and the accelerated rollout of relevant incentive policies in recent years has paved the way for the rapid development of the energy storage industry, propelling it into a stage of large-scale development.

[0003] Energy storage involves a wide range of fields, and broadly speaking, energy storage technologies can be divided into physical energy storage and electrochemical energy storage. Electrochemical energy storage is a general term for battery-based energy storage, and it is currently a key area of ​​development, with lithium-ion batteries being the core of this development.

[0004] The energy storage industry is in a phase of rapid technological development, but a series of problems have also emerged in the process. No single energy storage technology has yet achieved a dominant position.

[0005] Generally, electrochemical energy storage systems have multiple parallel branches. Inconsistencies between these branches can generate surge currents. If these surge currents exceed the battery's charge / discharge rate tolerance, they can cause irreversible damage to the battery, affecting its charge / discharge performance, lifespan, and safety. Furthermore, excessively high surge currents can cause overload and premature failure of high-voltage switches in the energy storage electrical system, reducing the system's reliability.

[0006] Common methods for resolving or suppressing surge current circulation include direct switching based on voltage judgment, parallel connection using unidirectional diode isolation, adding DC isolation to a single energy storage battery cluster, and parallel connection after pre-charge resistor buffering. However, all of these methods have certain technical and engineering limitations. For example, direct switching based on voltage judgment cannot achieve automatic parallel connection under large voltage differentials, and forced parallel connection poses significant damage and safety risks to the battery. While diode and DC isolation schemes can achieve direct parallel connection, the cost of diodes, DC converters, and additional electrical components is very high during high-power discharge in energy storage systems, hindering industrial applications. Pre-charge resistor buffering schemes cannot quickly achieve voltage consistency for parallel connection; if a consistent voltage is quickly obtained, the power required is enormous, consuming too much battery energy and leading to system energy waste, making them impractical for engineering implementation. Summary of the Invention

[0007] (a) Purpose of the invention

[0008] The purpose of this application is to provide a control circuit and control method for an energy storage system with multiple battery clusters connected in parallel to solve the circulating current problem caused by high surge impact due to voltage inconsistency when multiple parallel energy storage battery clusters are connected in the system.

[0009] (II) Technical Solution

[0010] According to a first aspect of the embodiments of this application, a control circuit for a parallel energy storage system with multiple energy storage battery clusters is provided, the circuit including:

[0011] An energy storage system containing N energy storage battery clusters, where N is a positive integer;

[0012] There are N energy storage battery cluster management modules, each corresponding to one of the energy storage battery clusters. Each energy storage battery cluster management module is used to collect the status information of its corresponding energy storage battery cluster and manage its corresponding battery cluster according to the collected information and preset control logic.

[0013] The system management controller is used to issue control signals based on the aggregated status information of N energy storage battery clusters, so that the energy storage battery cluster management module can control its corresponding energy storage battery cluster.

[0014] A DC-DC converter is used to perform charging / discharging operations according to the control signal.

[0015] In some optional embodiments of this application, the energy storage system of the energy storage battery cluster includes:

[0016] Management module for energy storage battery clusters;

[0017] Positive discharge switch;

[0018] A positive charging switch is connected in parallel with the positive discharging switch, and both the positive charging switch and the positive discharging switch are located at the positive terminal of their respective energy storage battery clusters.

[0019] The negative switch is located at the negative terminal of its corresponding energy storage battery cluster;

[0020] The management module of the energy storage battery cluster is used to collect the status information of its corresponding energy storage battery cluster and execute the opening / closing actions of the positive discharge switch, positive charging switch and negative switch according to the preset control logic.

[0021] In some optional embodiments of this application, the energy storage system of the energy storage battery cluster further includes: a fuse;

[0022] The fuse is positioned between its corresponding energy storage battery cluster and the positive discharge switch.

[0023] In some optional embodiments of this application, the N energy storage battery clusters are arranged in parallel with each other.

[0024] In some optional embodiments of this application, the total positive terminal of the parallel-connected energy storage battery cluster is connected to the positive input terminal of the DC-DC converter;

[0025] The total negative terminal of the parallel-connected energy storage battery cluster is connected to the negative input terminal of the DC-DC converter.

[0026] In some optional embodiments of this application, a communication module is also included:

[0027] The communication module is used for data interaction between the system management controller, the energy storage battery cluster management module, and the DC-DC converter.

[0028] In some optional embodiments of this application, the status information includes voltage information, current information, temperature information, and SOC information.

[0029] In some optional embodiments of this application, the DC-DC converter is a bidirectional converter.

[0030] According to a second aspect of the embodiments of this application, a parallel energy storage system of multiple energy storage battery clusters is provided. The system may include: the energy storage battery clusters described in any one of the embodiments of the first aspect being connected in parallel with a control circuit and an electrical load.

[0031] According to a third aspect of the embodiments of this application, a method for parallel control of multiple energy storage battery clusters is provided, the method including:

[0032] Collect voltage information for all energy storage battery clusters;

[0033] Compare the voltage levels of different energy storage battery clusters and rank them.

[0034] The positive discharge switch and negative discharge switch corresponding to the energy storage battery cluster with the highest closing voltage;

[0035] The total voltage of the battery cluster with the second highest voltage and the battery cluster that has been integrated into the energy storage is determined sequentially.

[0036] If it is determined that the voltage difference of all battery clusters is within the range that can be safely connected directly, then all positive discharge switches and negative switches are closed directly, and the DC-DC converter does not start working.

[0037] If the voltage difference between the energy storage battery cluster and the total voltage difference of the already connected energy storage battery clusters is higher than the allowable range, then first close the positive charging switch and negative switch corresponding to the energy storage battery cluster, and enable the DC-DC converter to output appropriate charging parameters to quickly charge the energy storage battery cluster until it reaches the allowable connection voltage range and then stop. Then open the positive charging switch and close the positive discharging switch.

[0038] (III) Beneficial Effects

[0039] The above-mentioned technical solution of this application has the following beneficial technical effects:

[0040] The circuit of this application embodiment can realize the mutual replenishment of energy between energy storage battery clusters within the energy storage system through energy transfer, ultimately achieving state consistency and ensuring the safety and reliability of multiple battery clusters being connected. The DC-DC converter used has high efficiency and low energy loss. Furthermore, the control circuit structure is simple and easier to implement in engineering compared to general technical solutions. The entire energy storage system only needs to be configured with one DC-DC converter and related control circuit switches. Compared to the existing technical solution of setting a DC-DC converter for each battery cluster, the cost is significantly reduced. Attached Figure Description

[0041] Figure 1 is a schematic diagram of the control circuit structure of an energy storage system with multiple energy storage battery clusters connected in parallel in an exemplary embodiment of this application;

[0042] Figure 2 is a flowchart of an energy storage system control method with multiple energy storage battery clusters connected in parallel in an exemplary embodiment of this application;

[0043] Figure 3 is a flowchart of a control method for an energy storage system with multiple energy storage battery clusters connected in parallel, according to a specific embodiment of this application.

[0044] Figure 4 is a flowchart of the high-efficiency discharge control of the DC-DC converter in reverse operation in an exemplary embodiment of this application. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this application. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0046] The accompanying drawings illustrate layer structure diagrams according to embodiments of this application. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0047] Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0048] In the description of this application, it should be noted that the terms "first", "second", and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0050] The following description, in conjunction with the accompanying drawings, details the energy storage battery cluster integration control circuit and energy storage battery cluster integration control method provided in this application through specific embodiments and application scenarios.

[0051] like Figure 1 As shown, in a first aspect of this application embodiment, a control circuit for an energy storage system with multiple energy storage battery clusters connected in parallel is provided. This circuit may include:

[0052] An energy storage system containing N energy storage battery clusters, where N is a positive integer;

[0053] There are N energy storage battery cluster management modules, each corresponding to one of the energy storage battery clusters. Each energy storage battery cluster management module is used to collect the status information of its corresponding energy storage battery cluster and manage its corresponding battery cluster according to the collected information and preset control logic.

[0054] The system management controller is used to issue control signals based on the aggregated status information of N energy storage battery clusters, so that the energy storage battery cluster management module can control its corresponding energy storage battery cluster.

[0055] A DC-DC converter is used to perform charging / discharging operations according to the control signal.

[0056] The circuit in the above embodiments can achieve mutual energy replenishment between energy storage battery clusters within the energy storage system through energy transfer, ultimately achieving state consistency and ensuring the safety and reliability of multiple battery clusters being connected. The DC-DC converter used has high efficiency and low energy loss. Furthermore, the control circuit structure is simple and easier to implement in engineering compared to general technical solutions. The entire energy storage system only needs to be configured with one DC-DC converter and related control circuit switches. Compared to the existing technical solution of setting a DC-DC converter for each battery cluster, the cost is significantly reduced.

[0057] In some optional embodiments of this application, the energy storage system of the energy storage battery cluster includes:

[0058] Management module for energy storage battery clusters;

[0059] Positive discharge switch;

[0060] A positive charging switch is connected in parallel with the positive discharging switch, and both the positive charging switch and the positive discharging switch are located at the positive terminal of their respective energy storage battery clusters.

[0061] The negative switch is located at the negative terminal of its corresponding energy storage battery cluster;

[0062] The management module for the energy storage battery cluster is used to collect the status information of its corresponding energy storage battery cluster and execute the opening / closing actions of the positive discharge switch, positive charging switch, and negative switch according to the preset control logic.

[0063] In some optional embodiments of this application, the energy storage system of the energy storage battery cluster further includes: a fuse;

[0064] The fuse is positioned between its corresponding energy storage battery cluster and the positive discharge switch.

[0065] In this embodiment, the fuse is installed at the positive or negative terminal of the power supply circuit of each energy storage battery cluster; it can be used for overcurrent and short circuit protection of the energy storage battery cluster.

[0066] In some optional embodiments of this application, the N energy storage battery clusters are arranged in parallel with each other.

[0067] In some optional embodiments of this application, the total positive terminal of the parallel-connected energy storage battery cluster is connected to the positive input terminal of the DC-DC converter;

[0068] The total negative terminal of the parallel-connected energy storage battery cluster is connected to the negative input terminal of the DC-DC converter.

[0069] In some optional embodiments of this application, a communication module is also included:

[0070] The communication module is used for data interaction between the system management controller, the energy storage battery cluster management module, and the DC-DC converter.

[0071] In some optional embodiments of this application, the status information includes voltage information, current information, temperature information, and SOC information.

[0072] In some optional embodiments of this application, the DC-DC converter is a bidirectional converter.

[0073] According to a second aspect of the embodiments of this application, a multi-energy storage battery cluster parallel control system is provided, which may include: the energy storage battery cluster inline control circuit and the electrical load as described in any one of the embodiments of the first aspect.

[0074] In a specific embodiment of this application, the circuit connection relationship can be as follows:

[0075] a. The positive terminals of each energy storage battery cluster are connected in parallel after being sequentially connected to a fuse and a positive terminal discharge switch;

[0076] b. The negative terminals of multiple energy storage batteries are connected in parallel after being connected to the negative discharge switch;

[0077] c. Connect the positive and negative input terminals of the DC-DC converter to the total positive and total negative terminals of the parallel battery pack, respectively.

[0078] d. One end of the positive charging switch of each energy storage battery cluster is connected to the front end of the positive discharging switch, and the other end is connected to the positive output terminal of the DC-DC converter.

[0079] e. The negative output terminal of the DC-DC converter is connected to the total negative terminal of the parallel battery pack;

[0080] f. After multiple energy storage batteries are connected in parallel, the output electrical energy is connected to the electrical load to supply power to the outside.

[0081] e. The system management controller, each energy storage battery cluster management unit, DC-DC converter, and electrical loads are connected via communication lines to form a communication network for mutual data exchange.

[0082] In summary, such as Figure 1As shown, the control circuit includes: energy storage battery clusters 1 to n, corresponding energy storage battery cluster management units BCU1 to BCUn, fuses f1 to fn, positive discharge switches K1+ to Kn+, positive charging switches KC1+ to KCn+, negative switches K1- to Kn-, a DC-DC converter, a system management controller SMC, and electrical loads. Energy storage battery clusters 1 to n are connected in series with fuses f1 to fn, and then a discharge circuit is formed by the positive discharge switches K1+ to Kn+ on the positive terminal and the negative switches K1- to Kn- on the negative terminal to supply power to the electrical load. One end of the positive charging switches KC1+ to KCn+ is connected to the positive output of the DC-DC converter, and the other end is connected in parallel between Kn+ and fn to recharge energy storage battery clusters 1 to n. The input terminals of the DC-DC converter are connected to the positive and negative terminals of the parallel-connected energy storage battery clusters. The positive output of the DC-DC converter is connected to one end of the positive charging switches KC1+~KCn+, and the negative output is connected to the negative terminal. The DC-DC converter is used to perform charging operations in a timely manner according to the control commands of the SMC. Fuses f1~fn are used for overcurrent and short-circuit protection of energy storage battery clusters 1 to n, respectively. BCU1~BCUn are used to collect the status information of energy storage battery clusters 1 to n, such as battery voltage, current, temperature, and SOC, and to execute the opening / closing actions of Kn+, Kn-, and KCn+. The System Management Controller (SMC) acts as the central control unit, coordinating and controlling the operation of the DC-DC converter, BCU1~BCUn, and the electrical loads. The SMC, DC-DC converter, BCU1~BCUn, and electrical loads form a communication network through communication connections for data exchange between them.

[0083] like Figure 2 As shown, in a third aspect of the embodiments of this application, a method for controlling the integration of multiple energy storage battery clusters is provided, the method including:

[0084] S210: The system management controller collects voltage information of all energy storage battery clusters in real time;

[0085] S220: The system management controller compares the voltage levels of the energy storage battery clusters based on real-time data and sorts them accordingly;

[0086] S230: The system management controller commands the energy storage battery cluster with the highest battery cluster voltage to close the corresponding positive discharge switch and negative discharge switch via a communication connection.

[0087] S240: The system management controller sequentially judges the total voltage of the second highest voltage battery cluster and the battery clusters already connected to the energy storage;

[0088] S250: If the voltage difference of all battery clusters is within the range that can be safely connected directly, then close all positive discharge switches and negative switches directly, and the DC-DC converter will not start working.

[0089] S260: If the voltage difference between the energy storage battery cluster and the total voltage of the already connected energy storage battery cluster is higher than the allowable range, first close the positive charging switch and negative switch corresponding to the energy storage battery cluster, and enable the DC-DC converter to output appropriate charging parameters to quickly charge the energy storage battery cluster with lower voltage until it reaches the allowable connection voltage range, then disconnect the positive charging switch and close the positive discharging switch.

[0090] Combination Figure 1 To explain the control method in detail, after the system is powered on, the energy storage battery cluster management unit of each energy storage battery cluster collects and broadcasts the voltage information of the corresponding battery cluster; the system management controller collects information and compares the voltage levels between battery clusters. If the voltage of energy storage battery cluster n is the highest, the positive and negative discharge switches corresponding to energy storage battery cluster n are closed. Then, the system management controller sequentially judges the voltage difference between the second-highest voltage battery cluster and the total voltage of the already connected battery clusters. Ideally, if the system management controller determines that the voltage difference of all battery clusters is within the range that can be safely connected directly, it will sequentially close all positive discharge switches and negative switches, and the DC-DC converter will not start working. If, during the voltage judgment process, the voltage difference between the energy storage battery cluster n and the total voltage of the previously connected n-1 battery clusters is higher than the allowable range, the system management controller will close the positive charging switch and negative switch corresponding to energy storage battery cluster n, and enable the DC-DC converter to output appropriate charging parameters to quickly charge energy storage battery cluster n according to the preset algorithm. During the fast charging process, if the system management controller determines that the voltage difference between energy storage battery cluster n and the total voltage is within the allowable range, it will stop enabling the DC-DC converter output, then disconnect the positive charging switch, close the positive discharge switch, and the energy storage battery cluster n will be connected.

[0091] The employed DC-DC converter enables energy transfer between energy storage battery clusters, ensuring consistency and safe integration between them without requiring external energy input.

[0092] The DC-DC converter used can be bidirectional, meaning it can operate in reverse. After the energy storage battery clusters are safely connected, the system management controller controls the positive discharge switch of each energy storage battery cluster to open and the positive charging switch to close, thus creating a discharge circuit. At this time, the DC-DC converter operates in reverse and outputs a stable voltage that allows the electrical load to operate efficiently.

[0093] like Figure 3As shown, after the system is powered on, BCU1~BCUn collect and broadcast the voltage information (U1~Un) of the corresponding battery clusters. SMC collects the information and compares the voltage levels between battery clusters. If the voltage U1 of energy storage battery cluster 1 is the highest, then the positive and negative discharge switches K1+ and K1- corresponding to energy storage battery cluster 1 are closed first. Then, the voltage of the battery cluster with the second highest voltage and the total voltage of the battery clusters already connected are judged in turn. Ideally, if the voltage difference of all battery clusters is determined to be within the range that can be safely connected directly, then all discharge switches K1+~Kn+ and K1-~Kn- are closed directly, and the DC-DC converter does not start working. If, during the sequential voltage assessment process, the voltage difference between the energy storage battery cluster n and the total voltage U0 of the previously connected n-1 battery clusters exceeds the allowable range, the SMC first closes KCn+ and Kn-, and according to the preset algorithm, enables the DC-DC converter to output appropriate charging parameters to quickly charge the energy storage battery cluster n until it reaches the allowable connection voltage range, then stops, and then opens KCn+ and closes Kn+ to achieve safe connection of the energy storage battery cluster n.

[0094] like Figure 4 As shown, this illustrates the efficient discharge control in a bidirectional DC-DC converter: when the energy storage battery clusters are safely connected, the function is to charge the battery clusters together, maintaining consistency between the battery clusters; after the energy storage battery clusters are safely connected, Kn is disconnected, and the KCn circuit is switched to close to become a discharge circuit. At this time, the DC-DC converter operates in reverse, and the output load can operate at a stable voltage with high efficiency.

[0095] This application aims to protect a control circuit and method for integrating energy storage battery clusters, such as... Figure 1 As shown, the energy storage battery clusters integrated into the control circuit include energy storage battery clusters 1 to n. Each energy storage battery cluster is equipped with an energy storage battery cluster management unit. Each energy storage battery cluster has a fuse, a positive discharge switch, and a positive charge switch at its positive terminal; and a negative switch at its negative terminal. The energy storage system includes a system management controller and electrical loads. The DC-DC converter is used to perform charging / discharging operations in a timely manner according to the control commands of the system management controller. The fuses are used for overcurrent and short-circuit protection of energy storage battery clusters 1 to n. The energy storage battery cluster management units are used to collect status information of energy storage battery clusters 1 to n, such as battery voltage, current, temperature, and SOC, and to execute the opening / closing actions of the positive discharge switch, positive charge switch, and negative switch. The system management controller, as the central control unit, is used to coordinate / control the operation between the DC-DC converter, the energy storage battery cluster management units, and the electrical loads.

[0096] Multiple energy storage battery clusters are connected in parallel after their positive terminals are sequentially connected to a fuse and a positive discharge switch. The negative terminals of the multiple energy storage battery clusters are also connected in parallel after being connected to a negative discharge switch. A DC-DC converter is included in the circuit, with its positive and negative input terminals connected to the total positive and negative terminals of the parallel battery clusters, respectively. One end of the positive charging switch of each energy storage battery cluster is connected to the front end of the positive discharge switch, and the other end is connected to the positive output terminal of the DC-DC converter. The negative output terminal of the DC-DC converter is connected to the total negative terminal of the parallel battery clusters. After the multiple energy storage battery clusters are connected in parallel, the output power is supplied to the electrical load. A communication network is formed between the system management controller, the energy storage battery cluster management unit, the DC-DC converter, and the electrical load to facilitate data exchange, and communication is established via communication lines.

[0097] In addition, such as Figure 3 As shown, the application also provides a method for controlling the integration of energy storage battery clusters, including: after the system is powered on, the energy storage battery cluster management unit of each energy storage battery cluster collects and broadcasts the voltage information of the corresponding battery cluster; the system management controller collects the information and compares the voltage levels between battery clusters; if the voltage of energy storage battery cluster n is the highest, then the positive and negative discharge switches corresponding to energy storage battery cluster n are closed first. Then, the voltage of the battery cluster with the second highest voltage and the total voltage of the already integrated battery clusters are judged sequentially. Ideally, if the voltage difference of all battery clusters is determined to be within the range where it is safe to directly integrate, then all positive discharge switches and negative switches are directly closed, and the DC-DC converter does not start working. If, during the sequential voltage assessment process, the voltage difference between the energy storage battery cluster n and the total voltage difference of the previously connected n-1 battery clusters exceeds the allowable range, the system management controller first closes the positive charging switch and negative switch corresponding to the energy storage battery cluster n, and according to the preset algorithm, enables the DC-DC converter to output appropriate charging parameters to quickly charge the energy storage battery cluster n until it reaches the allowable connection voltage range, then stops, and then disconnects the positive charging switch and closes the positive discharging switch to achieve safe connection of the energy storage battery cluster n.

[0098] Considering the broad adaptability of voltage matching between energy storage systems and load voltages, DC-DC converters can also be bidirectional converters. Through the overall identification and control of the system management controller, the DC-DC converter can operate in reverse. Specifically, when the energy storage battery clusters are safely connected, the converter performs a charging function between battery clusters, maintaining consistency between them. After the energy storage battery clusters are safely connected, the positive discharge switches of each battery cluster are opened, and the positive charging switches are closed to create a discharge circuit. At this time, the DC-DC converter operates in reverse, outputting a stable voltage that allows the electrical load to operate efficiently. Compared to the voltage fluctuations when operating directly with the battery voltage, this reverse operating mode results in a more stable output voltage (the input voltage of the electrical load), thereby improving the efficiency of the entire energy storage power supply system and reducing energy consumption. Due to the bidirectional operating nature of the DC-DC converter, the voltage of the energy storage battery clusters and the voltage of the electrical load are decoupled, allowing for more flexible configuration.

[0099] The control circuit structure employed in this application's embodiments enables energy replenishment between energy storage battery clusters within the energy storage system through energy transfer, ultimately achieving state consistency and ensuring the safety and reliability of multiple battery clusters connected in parallel. The DC-DC converters used are generally highly efficient with minimal energy loss. Under the premise of ensuring a reasonable battery charging rate, a single high-power DC-DC converter can be used to achieve rapid energy transfer between energy storage battery clusters with minimal energy loss. Furthermore, the control circuit described in this invention can be extended to various practical application scenarios, such as automatic maintenance, charging processes, and discharging processes, all of which can be designed with reasonable control methods to automatically adjust the state consistency between energy storage battery clusters. Moreover, the use of a bidirectional DC-DC converter allows for a stable output voltage for reverse operation after safe connection, enabling efficient operation of the electrical load and achieving the highest efficiency of the entire system.

[0100] The control circuit has a simple structure and is easier to implement in engineering compared to general technical solutions. The entire energy storage system only requires a single DC-DC converter and related control circuit switches, which significantly reduces costs compared to other solutions that require a DC-DC converter for each battery cluster.

[0101] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A control circuit for an energy storage system with multiple energy storage battery clusters connected in parallel, characterized in that, include: An energy storage system comprising N energy storage battery clusters; The energy storage battery clusters are connected in parallel among the N energy storage battery clusters; The energy storage system also includes N energy storage battery cluster management units, N positive discharge switches, N positive charging switches, and N negative switches, where N is a positive integer; The positive terminal of each energy storage battery cluster is connected to the total positive terminal through a positive discharge switch, and the negative terminal of each energy storage battery cluster is connected to the total negative terminal through a negative switch. The positive terminal of each energy storage battery cluster is also connected to one end of a positive charging switch, and the other end of each positive charging switch is connected to the positive output / positive input of the DC-DC converter; Connect the positive input / positive output of the DC-DC converter to the total positive, connect the negative input / negative output of the DC-DC converter to the total negative, and connect the negative output / negative input of the DC-DC converter to the total negative. The DC-DC converter is connected to the system management controller and is used to perform charging / discharging operations according to control signals. The DC-DC converter is a bidirectional conversion type. The positive and negative terminals are connected to the two ends of the electrical load. The energy storage battery cluster management unit corresponds one-to-one with the energy storage battery cluster. The energy storage battery cluster management unit is used to collect the status information of its corresponding energy storage battery cluster, and manage its corresponding energy storage battery cluster according to the collected status information and preset control logic, and execute the opening / closing actions of the positive discharge switch, positive charging switch and negative switch. The system management controller is connected to N energy storage battery cluster management units and is used to issue control signals based on the status information of the energy storage battery clusters so that the energy storage battery cluster management units can control their corresponding energy storage battery clusters. The system management controller collects voltage information from all energy storage battery clusters in real time; The system management controller compares and sorts the voltage levels of the energy storage battery clusters based on real-time data. The system management controller controls the positive discharge switch and negative switch corresponding to the highest voltage energy storage battery cluster to close via communication connection commands; The system management controller sequentially determines the total voltage of the energy storage battery cluster with the second highest voltage and the energy storage battery clusters that have already been connected; If the voltage difference of all energy storage battery clusters is within the range that can be safely connected directly, then all positive discharge switches and negative switches are closed directly, and the DC-DC converter does not start working. If the voltage difference between the energy storage battery cluster and the total voltage difference of the already connected energy storage battery clusters is higher than the allowable range, then first close the positive charging switch and negative switch corresponding to the energy storage battery cluster, and enable the DC-DC converter to output appropriate charging parameters to quickly charge the energy storage battery cluster with lower voltage until it reaches the allowable connection voltage range, then stop, then open the positive charging switch and close the positive discharging switch. After the energy storage battery clusters are safely connected, the system management controller controls the positive discharge switch of each energy storage battery cluster to open and the positive charging switch to close, turning it into a discharge circuit. At this time, the DC-DC converter works in reverse and outputs a stable voltage that can work efficiently to the electrical load.

2. The control circuit for the energy storage system with multiple energy storage battery clusters connected in parallel according to claim 1, characterized in that, The energy storage system also includes multiple fuses; The fuse is located at the positive or negative terminal of its corresponding energy storage battery cluster.

3. The control circuit for the energy storage system with multiple energy storage battery clusters connected in parallel according to claim 1, characterized in that, Status information includes voltage, current, temperature, and SOC (State of Charge).

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