Control method for energy storage system, and battery management system and energy storage system

Abstract

Provided in the present application are a control method for an energy storage system, and a battery management system and an energy storage system, which are applied to the technical field of batteries. The method comprises: when determining that a high-voltage power-on condition has been met, sending an isolation switch closing instruction to an isolation switch driving apparatus, wherein the isolation switch closing instruction is used for instructing the isolation switch driving apparatus to control an isolation switch to close; and when determining that the isolation switch has been closed, controlling the power-on of a battery cluster to be powered on in an energy storage system. In the embodiments of the present application, the state of the isolation switch is controlled by means of a control signal, thereby improving the safety in powering on the battery cluster; in addition, the battery cluster is powered on on the basis of the state of the isolation switch, thereby improving the stability of the energy storage system.

Description

Control methods for energy storage systems, battery management systems and energy storage systems

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411997564.7, filed on December 31, 2024, entitled “Control Method, Battery Management System and Energy Storage System for Energy Storage System”, and to Chinese Patent Application No. 202411997557.7, filed on December 31, 2024, entitled “Method and System for Handling Faults in Energy Storage Battery Cells”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, and more specifically, to a control method for an energy storage system, a battery management system, and an energy storage system. Background Technology

[0004] With the rapid development of the energy storage industry market, the commercial applications of energy storage are becoming more and more widespread, mainly concentrated in renewable energy grid connection, frequency regulation ancillary services, power transmission and distribution, electric vehicle photovoltaic-storage charging stations, and wind and solar power plants.

[0005] The connection and disconnection of the high-voltage circuit of an energy storage system are usually manually adjusted by adjusting the isolating switch, which is quite dangerous due to the manual operation. Summary of the Invention

[0006] The purpose of this application is to provide a control method for an energy storage system, a battery management system, and an energy storage system, which can control the opening and closing of the isolating switch through signals, thereby improving the safety of controlling the opening and closing of the high-voltage circuit.

[0007] In a first aspect, embodiments of this application provide a control method for an energy storage system, including:

[0008] Once the conditions for high-voltage power-on are met, a disconnector closing command is sent to the disconnector drive device. This disconnector closing command is used to instruct the disconnector drive device to control the disconnector to close.

[0009] Once the isolating switch is closed, the battery clusters in the energy storage system that are to be powered on are powered on.

[0010] This application embodiment controls the state of the disconnect switch through control signals, which improves the safety of powering on the battery cluster. Furthermore, powering on the battery cluster based on the state of the disconnect switch improves the stability of the energy storage system.

[0011] In any embodiment, before sending the disconnector closing command to the disconnector drive device, the method further includes:

[0012] Power on the disconnect switch drive device; the disconnect switch drive device is located between the positive terminal of the battery cluster and the high-voltage bus of the energy storage system.

[0013] This application embodiment controls the power-on of the disconnect switch drive device, making the disconnect switch drive device in a working state, and enabling it to respond to the disconnect switch closing command more reliably.

[0014] In any embodiment, powering on the disconnector drive device includes:

[0015] The main negative switch and precharge switch on the branch where the battery cluster to be powered is located are closed, and the precharge circuit of the battery cluster to be powered is used to power the isolation switch drive device. The main negative switch is located between the negative terminal of the battery cluster and the negative terminal of the high voltage bus, and the precharge switch is located between the positive terminal of the battery cluster and the positive terminal of the high voltage bus.

[0016] In this embodiment, the pre-charging circuit of multiple battery clusters powers the isolating switch drive device, sharing the current after power-on and improving the lifespan of the pre-charging resistors on each branch.

[0017] In any embodiment, controlling the battery cluster to be powered on in the energy storage system includes:

[0018] When the voltage difference across the main positive switch on the branch where the battery cluster to be powered is located is less than the first preset voltage difference, the main positive switch is closed and the pre-charge switch is opened to realize the power-on operation of the battery cluster to be powered.

[0019] In this embodiment, the pre-charge switch and the main negative switch are closed first, and the battery cluster is pre-charged through the pre-charge circuit so that the voltage of the battery cluster gradually approaches the voltage of the high-voltage bus. Then the main positive switch is closed, which reduces the excessive inrush current generated after the main positive switch is closed, thereby improving the safety of the main positive switch.

[0020] In any embodiment, the method further includes:

[0021] If the voltage difference across the main positive switch is not less than the first preset voltage difference within a preset time after the precharge switch is closed, a power-on failure message is reported.

[0022] In this embodiment, if the voltage across the main positive switch remains high within a preset time after the precharge switch is closed, it indicates a significant difference between the battery cluster voltage and the high-voltage bus voltage. This could be due to a battery cluster fault, a precharge circuit fault, or other faults in the energy storage system. In this case, reporting the power-on failure information allows the energy storage system to identify and respond to the fault, reducing the possibility of further fault expansion, preventing damage to electrical components in the energy storage system, and improving the reliability of the energy storage system.

[0023] In any embodiment, controlling the closing of the main negative switch and precharge switch on the branch where the battery cluster to be powered is located includes:

[0024] Control the main negative switch to close;

[0025] After a preset time has elapsed since the main negative switch was closed, the precharge switch is controlled to close.

[0026] In this embodiment, by first closing the main negative switch, a stable negative reference potential can be provided to the circuit. After a certain period of time, the pre-charge switch is closed, and the battery is slowly charged through the pre-charge circuit and pre-charge resistor. This avoids instantaneous large current surges and thus protects the electrical components in the circuit.

[0027] In any embodiment, powering on the disconnector drive device includes:

[0028] Send a power supply command to the disconnect switch drive power supply so that the disconnect switch drive power supply supplies power to the disconnect switch drive device.

[0029] The embodiments of this application provide power to the disconnector switch driver through a separate power supply, thereby improving the stability of the disconnector switch driver when powered on.

[0030] In any embodiment, the high-voltage power-on conditions include:

[0031] Received a high-voltage power-on command from the power controller.

[0032] In any embodiment, the high-voltage power-on condition further includes:

[0033] The number of battery clusters waiting to be powered on is greater than the preset number.

[0034] In this embodiment of the application, by setting the high-voltage power-on conditions and receiving the high-voltage power-on command sent by the power controller, the possibility of misoperation can be reduced; if the number of battery clusters to be powered is greater than the preset number, the system can have sufficient energy reserves and power output capabilities, reducing the risk of system instability due to insufficient energy.

[0035] In any embodiment, the battery clusters to be powered on are selected from a plurality of battery clusters using the following method:

[0036] The reference voltage is determined based on the voltages of multiple battery clusters;

[0037] Calculate the voltage difference between the voltage of each battery cluster and the reference voltage;

[0038] Battery clusters with a voltage difference less than the second preset voltage difference are identified as battery clusters to be powered on.

[0039] This application determines the battery clusters to be powered by voltage difference, thereby selecting battery clusters with more balanced voltage distribution. This helps to reduce voltage fluctuations, improve the consistency of battery clusters operating externally, avoid inrush current, and improve the stability of the energy storage system.

[0040] In any embodiment, the method is applied to the battery management system of the energy storage system, the battery management system including a primary controller and a secondary controller, each secondary controller being used to control the electrical components on the corresponding branch where the battery cluster is located; the primary controller is communicatively connected to the secondary controller, and the primary controller is communicatively connected to the disconnector drive device;

[0041] Sending a disconnector closing command to the disconnector drive device includes:

[0042] The primary controller sends a disconnector closing command to the disconnector drive device.

[0043] Powering on the disconnector switch drive includes:

[0044] The primary controller sends a power-on command to the secondary controller, which then powers on the disconnector switch drive.

[0045] This application embodiment achieves hierarchical management of the system by setting up a primary controller and a secondary controller, simplifying the control process. Furthermore, by setting up the secondary controller, more precise control and management of specific devices can be achieved, thereby improving the control accuracy of the energy storage system.

[0046] In any embodiment, the method further includes:

[0047] If the isolating switch fails to close within the preset time after the isolating switch closing command is sent, a power-on failure message will be reported.

[0048] In this embodiment of the application, if the isolating switch is detected to be unclosed after a preset time, a power-on failure message is reported and the power-on operation is stopped, thereby improving the safety of the energy storage system.

[0049] In any embodiment, the method further includes:

[0050] Upon receiving a high-voltage power-off command, a disconnector switch opening command is sent to the disconnector switch drive device. This disconnector switch opening command is used to instruct the disconnector switch drive device to control the disconnector switch to open.

[0051] The control unit disconnects the battery clusters in the high-voltage circuit from the high-voltage bus.

[0052] This application also provides a method to disconnect the isolation switch via a control signal to enable power-off operation of the battery cluster, thereby improving the safety of power-off.

[0053] Secondly, embodiments of this application provide a battery management system, which includes a battery management controller. The battery management controller is used to send a disconnector closing command to a disconnector drive device when it is determined that the high-voltage power-on conditions are met. The disconnector closing command is used to instruct the disconnector drive device to control the disconnector to close. The disconnector is located between the battery cluster and the high-voltage bus of the energy storage system. And, when it is determined that the disconnector is closed, it controls the battery cluster to be powered on in the energy storage system to be powered on.

[0054] The battery management system provided in this application embodiment controls the state of the disconnect switch through control signals, which improves the safety of powering on the battery cluster. Furthermore, powering on the battery cluster based on the state of the disconnect switch improves the stability of the energy storage system.

[0055] In any embodiment, the battery management controller includes a primary controller and a secondary controller, each secondary controller being used to control the electrical components on the corresponding branch where the battery cluster is located; the primary controller is communicatively connected to the secondary controller, and the primary controller is communicatively connected to the disconnect switch drive device.

[0056] This application embodiment achieves hierarchical management of the system by setting up a two-level controller, simplifies the control process, and allows for more precise control and management of specific devices through the setting of the two-level controller, thereby improving the control accuracy of the energy storage system.

[0057] Thirdly, embodiments of this application provide an energy storage system, a battery cluster and a battery management system, an isolation switch drive device and an isolation switch;

[0058] The disconnecting switch is installed on the high-voltage bus of the energy storage system, and the disconnecting switch drive device is used to drive the disconnecting switch to open or close.

[0059] The battery management system communicates with the disconnect switch drive and the battery cluster.

[0060] The battery management system is used to perform the method described in the first aspect.

[0061] This application embodiment controls the state of the disconnect switch through control signals, which improves the safety of powering on the battery cluster. Furthermore, powering on the battery cluster based on the state of the disconnect switch improves the stability of the energy storage system.

[0062] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing embodiments of this application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0063] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 is a diagram of an energy storage system architecture provided in an embodiment of this application;

[0065] Figure 2 is a schematic flowchart of the control method for a type of energy storage system provided in an embodiment of this application;

[0066] Figure 3 is a schematic diagram of an energy storage system architecture provided in an embodiment of this application;

[0067] Figure 4 shows the control flow of the primary controller provided in the embodiment of this application;

[0068] Figure 5 shows the control flow of the secondary controller provided in the embodiment of this application;

[0069] Figure 6 is a schematic diagram of the high-voltage power-down method provided in the embodiments of this application. Embodiments of the present invention

[0070] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0071] 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.

[0072] 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, unless otherwise explicitly defined.

[0073] 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.

[0074] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0075] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0076] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0077] As the installed capacity of new energy power plants such as wind and solar gradually increases in my country's power system, DC transmission, with its advantages of low loss, absence of capacitance effect, and long transmission distance, has become an important means to ensure the efficient collection, flexible transmission, and decentralized consumption of clean energy over a wide area.

[0078] Battery energy storage systems (BESS) are a highly efficient energy storage and conversion technology that uses batteries as energy storage carriers to store electrical energy for a specific period and supply it when needed. Through electrochemical reactions within the battery, it converts electrical energy into chemical energy for storage and then converts it back into electrical energy when needed. The electricity it provides has functions such as smoothing power transitions, peak shaving and valley filling, and frequency and voltage regulation, which is of great significance for the stable operation of power systems, the consumption of renewable energy, and electric vehicles.

[0079] Traditional energy storage systems involve manually closing or opening disconnecting isolating switches on the high-voltage bus during high-voltage power-on and power-off operations. This method is quite dangerous and can negatively impact system stability.

[0080] To address this technical problem, embodiments of this application provide a control method for an energy storage system, a battery management system, and an energy storage system. When high-voltage power-on is required, a closing command for the isolating switch is sent to the isolating switch driving device. Once the isolating switch is confirmed to be closed, the battery clusters in the energy storage system are controlled to receive high-voltage power. This avoids manual operation of the isolating switch, improving safety and system stability.

[0081] It is understood that the energy storage system provided in this application embodiment can be a stationary energy storage system or a mobile energy storage system. Stationary energy storage systems are typically installed in a fixed location and directly connected to the power grid, used to balance grid load, provide backup power, or support renewable energy grid connection. They are mainly used in power systems, renewable energy power plants, industrial parks, etc. Mobile energy storage systems are installed on movable carriers, such as vehicles or ships, facilitating transfer and use between different locations; a common form is the containerized system. They are mainly used in emergency power vehicles, marine propulsion systems, and power supply in remote areas.

[0082] Energy storage systems mainly consist of the following components:

[0083] Energy unit: This includes battery clusters / battery modules / battery boxes, which are encapsulated from a series of individual battery cells. The individual battery cell is the smallest unit of a battery and the main energy storage device.

[0084] Battery Management System (BMS): The core control device of an energy storage system, responsible for collecting and transmitting the real-time status of the battery cells and receiving control from other control systems. It primarily monitors parameters such as battery voltage, current, and temperature to ensure safe battery operation and optimize its performance and lifespan.

[0085] Energy storage converter (PCS): The PCS is the main energy conversion device, responsible for converting direct current (DC) to alternating current (AC). It has certain control functions and can be flexibly configured according to actual needs.

[0086] Energy Management System (EMS) (available in some systems): An EMS monitors, controls, and optimizes the performance of power generation or transmission systems. It can be used in small-scale systems, such as microgrids, to help industrial enterprises plan and utilize energy rationally while expanding production.

[0087] In addition, battery energy storage systems may also include auxiliary equipment such as temperature control systems, monitoring systems, access control systems, lighting systems, protection systems, and transformers.

[0088] The battery management system in the energy storage system of this application embodiment is used to control the high-voltage power-on and high-voltage power-off operations of the energy storage system.

[0089] Figure 1 is a diagram of an energy storage system architecture provided in an embodiment of this application. As shown in Figure 1, it mainly includes:

[0090] Multiple parallel battery clusters: Each battery cluster consists of multiple battery cells, which are connected in parallel, series, or mixed connections. It should be noted that in practical applications, battery clusters can also take other forms, such as battery modules or battery cabinets.

[0091] Disconnecting switch: Used to isolate high-voltage circuits, ensuring that the high-voltage circuit is disconnected from the battery pack when not in operation. Specifically, it can be an electric disconnecting switch.

[0092] Disconnecting switch drive unit: Controls the closing and opening of the disconnecting switch and requires power to operate. The disconnecting switch drive unit can be powered by the various pre-charge branches or by a separate power supply.

[0093] Main positive switch: connects the positive terminal of the battery cluster to the high-voltage bus.

[0094] Main negative switch: connects the negative terminal of the battery cluster to the high-voltage bus.

[0095] Precharge switch: Before the main positive switch is closed, the battery pack is precharged through the precharge circuit to reduce the impact of large current.

[0096] Pre-charge resistor: Used in the pre-charge circuit to reduce the voltage difference when the main positive switch is closed.

[0097] It should be noted that the main positive switch, main negative switch, and precharge switch can be relays, or solid-state relays (SSRs), IGBTs, DC contactors, etc.

[0098] Figure 2 is a schematic flowchart of a control method for an energy storage system provided in an embodiment of this application. As shown in Figure 2, the method includes:

[0099] Step 201: After confirming that the high voltage power-on conditions are met, send a disconnector closing command to the disconnector drive device. This disconnector closing command is used to instruct the disconnector drive device to control the disconnector to close.

[0100] Step 202: With the isolating switch closed, control the battery clusters in the energy storage system to be powered on.

[0101] In step 201, the high-voltage power-on conditions are preset and may include: the battery management system receiving a high-voltage command from the power controller; the battery management system determining that the current energy storage system is in normal operation and without faults; the number of battery clusters in the current energy storage system capable of providing power to external systems reaching a certain level; and environmental conditions such as temperature and humidity in the energy storage system meeting preset requirements, etc. Specific high-voltage power-on conditions can be set according to actual needs. High-voltage power-on refers to connecting some or all of the battery clusters in the energy storage system to the high-voltage bus for power transmission.

[0102] The control area disconnect switch drive unit is connected via wired or wireless means. When the battery management system determines that the high-voltage power-on conditions are met, it sends a disconnect switch closing command to the disconnect switch drive unit. This closing command instructs the disconnect switch drive unit to control the disconnect switch to close. The disconnect switch drive unit includes an electric operating mechanism responsible for providing the necessary force or power to the disconnect switch, enabling it to perform opening or closing operations as required. The electric operating mechanism typically uses a drive motor to drive the disconnect switch spindle via a voltage reduction device for opening and closing operations, improving operational convenience and efficiency.

[0103] In step 202, the battery management system determines whether to continue the subsequent high-voltage power-on operation by receiving feedback on the status of the isolating switch from the isolating switch driver. It is understood that the isolating switch driver can detect the isolating switch status using current detection, voltage detection, or a dedicated signal sensor. When the battery management system receives a closed isolating switch signal, it controls the battery clusters in the energy storage system to perform a high-voltage power-on operation. These battery clusters can be one or more randomly selected from the energy storage system, or they can be selected according to certain selection criteria.

[0104] This application embodiment controls the state of the disconnect switch through control signals, which improves the safety of powering on the battery cluster. Furthermore, powering on the battery cluster based on the state of the disconnect switch improves the stability of the energy storage system.

[0105] Based on the above embodiments, before sending the disconnector closing command to the disconnector drive device, the method further includes:

[0106] Power on the disconnect switch drive device; the disconnect switch drive device is located between the positive terminal of the battery cluster and the high-voltage bus of the energy storage system.

[0107] In the specific implementation process, when the isolating switch drive device is powered through each pre-charge branch, the isolating switch drive device is initially in a de-energized state. In order to enable the isolating switch drive device to receive and execute commands, and thus receive the isolating switch closing command, the isolating switch drive device can be powered on first. Specifically, this can be achieved by closing the pre-charge switch and the main negative switch on the branch where the battery cluster to be powered is located, thus connecting the pre-charge branch, and then powering the isolating switch drive device.

[0108] This application embodiment controls the power-on of the disconnect switch drive device, making the disconnect switch drive device in a working state, and enabling it to respond to the disconnect switch closing command more reliably.

[0109] In another embodiment, the disconnector drive device can be powered by a separate power source, ensuring it is always operational. In this case, the battery management system can directly send a disconnector closing command to the disconnector drive device. Alternatively, the separate power source can begin supplying power only after receiving a power supply command from the battery management system. Therefore, the battery management system can first send a power supply command to the separate power source, and then send the disconnector closing command after confirming the disconnector drive device is powered on.

[0110] In addition, the energy storage system can also be equipped with a backup battery. Specifically, a small-capacity backup battery or supercapacitor can power the disconnect switch drive device to ensure that it can work even when the high-voltage system is not powered.

[0111] Based on the above embodiments, controlling the power-on of the disconnector switch drive device includes:

[0112] The main negative switch and precharge switch on the branch where the battery cluster to be powered is located are closed, and the precharge circuit of the battery cluster to be powered is used to power the isolation switch drive device. The main negative switch is located between the negative terminal of the battery cluster and the negative terminal of the high voltage bus, and the precharge switch is located between the positive terminal of the battery cluster and the positive terminal of the high voltage bus.

[0113] In the specific implementation process, referring to Figure 1, each branch containing a battery cluster includes a pre-charge circuit. The pre-charge circuit includes a pre-charge switch and a pre-charge resistor. The pre-charge switch pre-charges the battery cluster through the pre-charge circuit before the main positive switch closes, reducing the inrush current when the main positive switch closes and protecting the battery and electrical components. After the pre-charge switch closes, the pre-charge resistor pre-charges the battery cluster with a lower current, gradually bringing the battery cluster voltage closer to the high-voltage bus voltage, thereby reducing the voltage difference when the main positive switch closes. The pre-charge resistor can be a single high-power resistor, multiple low-power resistors in parallel, or an adjustable pre-charge resistor. A single high-power resistor is suitable for situations with a small number of battery clusters. Multiple low-power resistors in parallel are suitable for situations with a large number of battery clusters, as this can distribute heat and improve the resistor's lifespan. An adjustable pre-charge resistor can adjust its resistance value according to actual needs to optimize the pre-charge current.

[0114] The battery management system can control the closing of the main negative switch and precharge switch on the branch where the battery cluster to be powered is located. After closing, it provides a power supply path for the isolating switch drive device, thereby powering on the isolating switch drive device.

[0115] It should be noted that each battery cluster's pre-charge circuit is also equipped with a pre-charge resistor. The pre-charge resistor reduces the inrush current, thus protecting the battery cluster. Furthermore, in the case of multiple battery clusters waiting to be powered on, since each battery cluster corresponds to a pre-charge circuit, the inrush current can be shared, protecting the pre-charge resistor.

[0116] In this embodiment, the pre-charging circuit of multiple battery clusters powers the isolating switch drive device, sharing the current after power-on and improving the lifespan of the pre-charging resistors on each branch.

[0117] Alternatively, the main negative switch and the pre-charge switch can be closed simultaneously, or the main negative switch can be closed first, and the pre-charge switch can be closed after a preset time, such as 10ms. In this embodiment, by closing the main negative switch first, a stable negative reference potential can be provided to the circuit. Closing the pre-charge switch after a certain time allows for slow charging of the battery through the pre-charge circuit and pre-charge resistor, avoiding instantaneous large current surges and thus protecting the electrical components in the circuit.

[0118] Based on the above embodiments, controlling the battery clusters to be powered on in the energy storage system includes:

[0119] When the voltage difference across the main positive switch on the branch where the battery cluster to be powered is located is less than the first preset voltage difference, the main positive switch is closed and the pre-charge switch is opened to realize the power-on operation of the battery cluster to be powered.

[0120] In the specific implementation process, after closing the pre-charge switch and the main negative switch, the voltage across the main positive switch will initially be relatively high. If the main positive switch is closed directly, it will cause current imbalance in the circuit. Under normal circumstances, the voltage difference across the main positive switch will gradually decrease. For safety reasons, when the voltage difference across the main positive switch is detected to be less than the first preset voltage difference, the main positive switch can be controlled to close, and the pre-charge switch can be controlled to open. After the isolating switch, the main positive switch, and the main negative switch are closed, the battery pack is connected to the high-voltage bus, thereby achieving power-on.

[0121] In this embodiment, the pre-charge switch and the main negative switch are closed first, and the battery cluster is pre-charged through the pre-charge circuit so that the voltage of the battery cluster gradually approaches the voltage of the high-voltage bus. Then the main positive switch is closed, which reduces the excessive inrush current generated after the main positive switch is closed, thereby improving the safety of the main positive switch.

[0122] Based on the above embodiments, the method further includes:

[0123] If the voltage difference across the main positive switch is not less than the first preset voltage difference within a preset time after the precharge switch is closed, a power-on failure message is reported.

[0124] In the specific implementation process, after closing the main negative switch and the precharge switch, the timing can be started. If the voltage difference across the main positive switch is not less than the first preset voltage difference within the preset time, it may be a fault in the energy storage system. In this case, the power-on operation should not be continued, and the battery management system can report the power-on failure information.

[0125] The battery management system can also perform power-off operations, namely disconnecting the isolating switch, as well as the already closed main negative switch and precharge switch.

[0126] In this embodiment, if the voltage across the main positive switch remains high within a preset time after the precharge switch is closed, it indicates a significant difference between the battery cluster voltage and the high-voltage bus voltage. This could be due to a battery cluster fault, a precharge circuit fault, or other faults in the energy storage system. In this case, reporting the power-on failure information allows the energy storage system to identify and respond to the fault, reducing the possibility of further fault expansion, preventing damage to electrical components in the energy storage system, and improving the reliability of the energy storage system.

[0127] Based on the above embodiments, the high-voltage power-on conditions include:

[0128] Received a high-voltage power-on command from the power controller.

[0129] In practical implementation, the power controller is a key device in the energy storage system. It precisely controls whether the battery is charged and discharged, and the charging and discharging power, based on the needs of the energy storage system and the battery status. Therefore, one of the conditions for high-voltage power-on is whether a high-voltage power-on command has been received from the power controller.

[0130] In addition, the high-voltage power-on conditions may also include: the number of battery clusters to be powered is greater than a preset number. Specifically, whether a battery cluster meets the power-on requirements can be determined in the following way:

[0131] The battery management system can obtain the voltage of each battery cluster in the energy storage system. If the voltage difference between more than a certain number of battery clusters is less than the preset voltage difference, then these battery clusters are battery clusters to be powered on, and high voltage power will be applied to these battery clusters in the future.

[0132] Specifically, multiple battery clusters can be sorted by voltage, and a reference voltage can be determined from this sort. In energy storage systems, determining which battery cluster to power on typically considers several factors, including safety, balance, system stability, and startup speed. Different application scenarios may choose different reference voltage methods. For example, the voltage of a battery cluster in the middle of the sort can be used as the reference voltage, as can the voltage of any battery cluster in the sort, or the average voltage of multiple battery clusters. Choosing a higher voltage in the sort as the reference voltage allows for faster system startup, reduces pre-charging time, and during pre-charging, the voltage difference between the higher-voltage battery cluster and the system's high-voltage bus is smaller, reducing the risk of inrush current. Choosing a lower voltage in the sort requires a longer pre-charging time, ensuring that all battery clusters reach a relatively high voltage before the main positive switch closes, reducing unbalanced current and improving the stability of the energy storage system. Choosing the voltage in the middle of the sort as the reference voltage results in a more even voltage distribution among the battery clusters, leading to a more stable energy storage system during pre-charging.

[0133] After determining the reference voltage, the voltage difference between each battery cluster and the reference voltage is calculated.

[0134] Battery clusters with a voltage difference less than a second preset voltage difference are identified as battery clusters to be powered on. The specific value of the second preset voltage difference can be set according to the actual situation.

[0135] By determining the battery clusters to be powered by the aforementioned voltage difference, battery clusters with more balanced voltage distribution can be selected, which helps to reduce voltage fluctuations, improve the consistency of battery clusters operating externally, avoid inrush current, and improve the stability of the energy storage system.

[0136] In different scenarios, the number of battery clusters that need to be powered by high voltage varies. Therefore, the number of battery clusters that need to be powered by high voltage each time can be preset. If the number of battery clusters to be powered by high voltage is greater than the preset number (e.g., 4), it means that one of the high voltage power-on conditions is met.

[0137] It should be noted that high-voltage power-on conditions may also include: the absence of fire-fighting faults or cell abnormalities (including cell overvoltage, cell undervoltage, etc.) in the energy storage system monitored by the battery management system.

[0138] This embodiment of the application reduces the possibility of misoperation by receiving a high-voltage power-on command from the power controller during the high-voltage power-on condition setting. The number of battery clusters to be powered on is greater than a preset number, ensuring sufficient energy reserves and power output capacity, thus reducing the risk of system instability due to insufficient energy. Based on the above embodiment, the energy storage system includes a primary controller and a secondary controller. Each secondary controller controls the electrical components on the corresponding branch where the battery cluster is located. The primary controller is communicatively connected to the secondary controller and also communicatively connected to the disconnector switch drive device.

[0139] Sending a disconnector closing command to the disconnector drive device includes:

[0140] The primary controller sends a disconnector closing command to the disconnector drive device.

[0141] Powering on the disconnector switch drive includes:

[0142] The primary controller sends a power-on command to the secondary controller, which then powers on the disconnector switch drive.

[0143] Figure 3 is a schematic diagram of an energy storage system architecture provided in an embodiment of this application. As shown in Figure 3, the battery management system in this energy storage system may include a battery management controller, which includes a primary controller (BMC) and multiple secondary controllers (SBMUs). Each battery cluster corresponds to one secondary controller, and the primary controller and secondary controllers communicate with each other. The primary controller is responsible for the management and signal transmission of the overall high-voltage control process. The secondary controller is used to control the electrical components on the branch where the corresponding battery cluster is located, such as controlling the opening and closing of the main positive switch, main negative switch, and precharge switch. Communication between the primary controller, secondary controller, and disconnector switch drive device can use communication protocols such as CAN bus, Ethernet, and Modbus.

[0144] The primary controller also communicates with the power controller (SMC) and the disconnector drive board. The primary controller can receive high-voltage power-on commands from the power controller. After receiving the high-voltage power-on command, the primary controller can further determine whether the energy storage system currently meets the high-voltage power-on conditions (because there may be system faults). If the high-voltage power-on conditions are met, it sends a disconnector closing command to the disconnector drive device.

[0145] If the disconnector drive is powered by the pre-charge circuit of the battery cluster, the primary controller can first send a power-on command to the secondary controller corresponding to the battery cluster to be powered on, so that the secondary controller closes the main negative switch and the pre-charge switch, thereby powering on the disconnector drive.

[0146] Figure 4 shows the control flow of the primary controller provided in an embodiment of this application, and Figure 5 shows the control flow of the secondary controller provided in an embodiment of this application. As shown in Figures 4 and 5:

[0147] Step 401: The primary controller receives the high-voltage power-on command sent by the power controller;

[0148] Step 402: Determine if the number of battery clusters meeting the power-on conditions is greater than a preset number; if the number of battery clusters meeting the power-on conditions is greater than the preset number, the primary controller broadcasts a high-voltage power-on command to the secondary controller, executing the process shown in Figure 5. Otherwise, a high-voltage power-on failure message is reported. It should be noted that the method for determining the battery clusters meeting the power-on conditions is the same as in the above embodiment, and will not be repeated here.

[0149] Step 403: Send the disconnect switch closing command; After receiving the high voltage power-on command and determining that the high voltage power-on conditions are met, the primary controller can start timing and send the disconnect switch closing command to the disconnect switch driver board after the timeout.

[0150] Step 404: Determine whether the isolating switch is closed; the primary controller determines whether the isolating switch is closed. If it is closed, proceed with the steps in Figure 5; if it is not closed, proceed with step 405.

[0151] Step 405: Timeout? Starting from the moment the disconnector closing command is sent, determine if the current time exceeds the set timeout duration. If the timeout duration is exceeded and the disconnector is not closed, proceed to step 406. If no timeout occurs, continue to step 404. The timeout duration can be set to 3 seconds, 4 seconds, etc.

[0152] Step 406: Report the failure to close the isolating switch and perform a high-voltage power-off operation.

[0153] The specific steps in Figure 5 are as follows:

[0154] Step 501: The secondary controller closes the main negative switch and the pre-charge switch; in order to power up the isolating switch drive device, the secondary controller can close the main negative switch and the pre-charge switch. When closing, the main negative switch can be closed first, and after a preset time, the pre-charge switch can be closed.

[0155] Step 502: Determine whether the isolating switch is closed; the primary controller sends the status of the isolating switch to the secondary controller, and the secondary controller determines whether the isolating switch is closed. If the isolating switch is closed, proceed to step 503.

[0156] Step 503: Determine whether the voltage across the main positive switch is less than the first preset voltage difference and whether a timeout has occurred. Upon receiving the message of the isolating switch closing and after the pre-charge switch is closed, start timing. If the current time exceeds the preset first duration and the voltage difference across the main positive switch is less than the first preset voltage difference, proceed to step 505; if the voltage difference across the main positive switch is not less than the first preset voltage difference, proceed to step 504. The timeout in this step can be set between 500ms and 10s. The first preset voltage difference can be set according to actual conditions, for example, it can be 5V, 10V, etc.

[0157] Step 504: Determine if timeout has occurred; after receiving the message that the isolating switch is closed and the precharge switch is closed, start timing. If the current time exceeds the preset second duration, proceed to step 507; if the second duration has not been exceeded, continue to step 503. The timeout period of this step can be greater than the timeout period in step 503.

[0158] Step 505: Close the main positive switch and disconnect the precharge switch;

[0159] Step 506: Report to the primary controller that the high-voltage power-on is complete;

[0160] Step 507: Report high voltage power-on failure to the primary controller.

[0161] It should be noted that during the high-voltage power-on process, the energy storage system can be equipped with some safety protection mechanisms, such as:

[0162] Overvoltage protection: If the battery cluster voltage exceeds the preset safety range during the high-voltage process, the high-voltage operation should be stopped immediately.

[0163] Overcurrent protection: If the current exceeds the preset safety range when the main positive switch is closed, the main positive switch should be disconnected immediately to prevent damage to electrical components.

[0164] Temperature protection: Monitors the temperature of the battery and electrical components. If the temperature exceeds the safe range, operation should be stopped immediately to prevent safety problems caused by overheating.

[0165] This application embodiment achieves hierarchical management of the system by setting up a primary controller and a secondary controller, which simplifies the control process. Furthermore, by setting up the secondary controller, more precise control and management of specific devices can be achieved, thereby improving the control accuracy of the energy storage system.

[0166] This application embodiment also provides a high-voltage power-off method, as shown in Figure 6. The high-voltage power-off method includes:

[0167] Step 601: Upon receiving a high-voltage power-off command, send a disconnect switch opening command to the disconnect switch drive device so that the disconnect switch drive device controls the disconnect switch to open.

[0168] Step 602: Control the battery cluster in the high-voltage circuit to disconnect from the high-voltage bus.

[0169] In practical implementation, the high-voltage power-down command can be sent from the power controller to the battery management system (BMS) or automatically generated by the BMS. Scenarios where the BMS automatically generates the high-voltage power-down command include, but are not limited to: during high-voltage power-up, if the isolating switch fails to close within a preset time period, the BMS can generate a high-voltage power-down command to execute the high-voltage power-down process. Another example is if, after closing the pre-charge switch and the main negative switch, the voltage difference across the main positive switch does not fall below a first preset voltage difference within a preset time period, the BMS will also generate a high-voltage power-down command. Furthermore, the BMS can also generate a high-voltage power-down command when it detects a fault in the energy storage system.

[0170] After determining that the high voltage needs to be cut off, the battery management system sends a disconnect switch opening command to the disconnect switch drive device and starts timing.

[0171] After receiving the disconnector's tripping command, the disconnector drive unit normally controls the disconnector to open. However, in some cases, the disconnector may fail to trip.

[0172] If the disconnecting switch opens within a preset time, the battery management system controls the battery cluster in the high-voltage circuit to disconnect from the high-voltage bus, indicating that the high-voltage power-off is complete.

[0173] If the disconnecting switch fails to open within a preset time, the battery management system will still control the battery clusters in the high-voltage circuit to disconnect from the high-voltage bus and report a message indicating that the disconnecting switch has failed to open.

[0174] In cases where the battery management controller comprises a primary controller and a secondary controller, after determining that a high-voltage power-down procedure needs to be executed, the primary controller sends a disconnector switch opening command to the disconnector switch drive device. Furthermore, the primary controller detects whether the disconnector switch is open, but regardless of whether the disconnector switch is open or not, it sends a high-voltage power-down command to the secondary controller. Upon receiving the high-voltage power-down command, the secondary controller controls the main positive switch and the main negative switch to open, thereby disconnecting the battery pack from the high-voltage bus and achieving high-voltage power-down.

[0175] This application also provides a method to disconnect the isolation switch via a control signal to enable power-off operation of the battery cluster, thereby improving the safety of power-off.

[0176] This application provides a battery management system, which includes a battery management controller. The battery management controller is mainly used to send a disconnect switch closing command to a disconnect switch driving device when it is determined that the high voltage power-on conditions are met. The disconnect switch closing command is used to instruct the disconnect switch driving device to control the disconnect switch to close. The disconnect switch is located between the battery cluster and the high voltage bus of the energy storage system. And, when it is determined that the disconnect switch is closed, it controls the battery cluster to be powered on in the energy storage system to be powered on.

[0177] Based on the above embodiments, the battery management controller may include a primary controller and a secondary controller. The primary controller is communicatively connected to the secondary controller. The primary controller is also communicatively connected to the power controller and to the disconnector drive device. The primary controller is used to receive some instructions sent by the power controller, such as high-voltage power-on instructions and high-voltage power-off instructions. When the primary controller receives the high-voltage power-on instruction sent by the power controller and detects that the conditions for high-voltage power-on are met, it sends a disconnector closing instruction to the disconnector drive device. If the disconnector drive device is not powered on, it can be powered on first; the specific power-on method can be found in the above embodiments. After the disconnector is closed, the primary controller broadcasts the high-voltage power-on instruction to the secondary controller. After receiving the high-voltage power-on instruction, the secondary controller controls the main negative switch and pre-charge switch on the corresponding battery cluster branch to close. When the voltage difference across the main positive switch is detected to be less than a certain value, the main positive switch is closed and the pre-charge switch is opened, thereby realizing the high-voltage power-on process of the battery cluster.

[0178] Based on the above embodiments, the battery management controller is also used to control the power-on of the disconnect switch drive device; wherein the disconnect switch drive device is located between the positive terminal of the battery cluster and the high-voltage bus of the energy storage system.

[0179] Based on the above embodiments, when the secondary controller controls the power-on of the battery cluster, it is specifically used for:

[0180] The main negative switch and precharge switch on the branch where the battery cluster to be powered is located are closed, and the precharge circuit of the battery cluster to be powered is used to power the isolation switch drive device. The main negative switch is located between the negative terminal of the battery cluster and the negative terminal of the high voltage bus, and the precharge switch is located between the positive terminal of the battery cluster and the positive terminal of the high voltage bus.

[0181] Based on the above embodiments, the secondary controller is specifically used for:

[0182] When the voltage difference across the main positive switch on the branch where the battery cluster to be powered is located is less than the first preset voltage difference, the main positive switch is closed and the pre-charge switch is opened to realize the power-on operation of the battery cluster to be powered.

[0183] Based on the above embodiments, the secondary controller is also used for:

[0184] If the voltage difference across the main positive switch is not less than the first preset voltage difference within a preset time after the precharge switch is closed, a power-on failure message is reported.

[0185] Based on the above embodiments, the secondary controller may employ the following steps when closing the main negative switch and the precharge switch:

[0186] Control the main negative switch to close;

[0187] After a preset time has elapsed since the main negative switch was closed, the precharge switch is controlled to close.

[0188] Based on the above embodiments, the high-voltage power-on conditions include:

[0189] Received a high-voltage power-on command from the power controller.

[0190] High-voltage power-on conditions may also include:

[0191] The number of battery clusters waiting to be powered on is greater than the preset number.

[0192] Based on the above embodiments, the battery clusters to be powered on are selected from multiple battery clusters using the following method:

[0193] The voltages of multiple battery clusters are sorted, and the voltage of the battery cluster in the middle position is used as the reference voltage.

[0194] Calculate the voltage difference between the voltage of each battery cluster and the reference voltage;

[0195] Battery clusters with a voltage difference less than the second preset voltage difference are identified as battery clusters to be powered on.

[0196] Based on the above embodiments, the primary controller can also be used to: if the isolating switch is still not closed within a preset time after sending the isolating switch closing command, report a power-on failure message.

[0197] Based on the above embodiments, the battery management controller is also used for:

[0198] Upon receiving a high-voltage power-off command, a disconnector switch opening command is sent to the disconnector switch drive device. This disconnector switch opening command is used to instruct the disconnector switch drive device to control the disconnector switch to open.

[0199] The control unit disconnects the battery clusters in the high-voltage circuit from the high-voltage bus.

[0200] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0201] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0202] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0203] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0204] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A control method for an energy storage system, characterized in that, include: When it is determined that the high voltage power-on conditions are met, a disconnector closing command is sent to the disconnector drive device. The disconnector closing command is used to instruct the disconnector drive device to control the disconnector to close. When the isolating switch is closed, the battery clusters in the energy storage system that are to be powered on are controlled to be powered on.

2. The method according to claim 1, characterized in that, Before sending the disconnector closing command to the disconnector drive device, the method further includes: The disconnector switch driver is powered on; wherein the disconnector switch driver is located between the positive terminal of the battery cluster and the high-voltage bus of the energy storage system.

3. The method according to claim 2, characterized in that, The power-on control of the disconnect switch drive device includes: The main negative switch and precharge switch on the branch where the battery cluster to be powered is located are closed, and the precharge circuit of the battery cluster to be powered is used to supply power to the isolation switch drive device. The main negative switch is located between the negative terminal of the battery cluster and the negative terminal of the high voltage bus, and the precharge switch is located between the positive terminal of the battery cluster and the positive terminal of the high voltage bus.

4. The method according to claim 2, characterized in that, The disconnecting switch is powered by a separate power supply; The power-on control of the disconnect switch drive device includes: A power supply command is sent to the individual power source so that the individual power source begins to supply power to the isolating switch drive device upon receiving the power supply command.

5. The method according to any one of claims 1-4, characterized in that, The process of controlling the battery clusters to be powered on in the energy storage system includes: When the voltage difference across the main positive switch on the branch where the battery cluster to be powered is located is less than the first preset voltage difference, the main positive switch is controlled to close and the pre-charge switch is controlled to open, so as to realize the power-on operation of the battery cluster to be powered.

6. The method according to claim 5, characterized in that, The method further includes: If, within a preset time after the precharge switch is closed, the voltage difference across the main positive switch is not less than the first preset voltage difference, a power-on failure message is reported.

7. The method according to any one of claims 3-6, characterized in that, The control of closing the main negative switch and precharge switch on the branch where the battery cluster to be powered is located includes: Control the main negative switch to close; After a preset time has elapsed since the main negative switch was closed, the precharge switch is controlled to close.

8. The method according to any one of claims 2-7, characterized in that, The power-on control of the disconnect switch drive device includes: A power supply command is sent to the disconnect switch drive power supply so that the disconnect switch drive power supply supplies power to the disconnect switch drive device.

9. The method according to any one of claims 1-8, characterized in that, The high-voltage power-on conditions include: Received a high-voltage power-on command from the power controller.

10. The method according to claim 9, characterized in that, The high-voltage power-on conditions also include: The number of battery clusters waiting to be powered on is greater than the preset number.

11. The method according to claim 10, characterized in that, The following method is used to select battery clusters from multiple battery clusters to be powered on: Calculate the voltage difference between the voltage of each battery cluster and the reference voltage; Battery clusters with a voltage difference less than a second preset voltage difference are identified as battery clusters to be powered on.

12. The method according to any one of claims 1-11, characterized in that, The method is applied to the battery management system of the energy storage system, which includes a primary controller and a secondary controller. Each secondary controller is used to control the electrical components on the corresponding branch where the battery cluster is located. The primary controller is communicatively connected to the secondary controller and is also communicatively connected to the disconnector drive device. Sending the disconnector closing command to the disconnector drive device includes: The primary controller sends the disconnector closing command to the disconnector drive device. The power-on control of the isolating switch drive device includes: The primary controller sends a power-on command to the secondary controller. The secondary controller responds to the power-on command and controls the disconnector switch drive device to power on.

13. The method according to any one of claims 1-12, characterized in that, The method further includes: If the disconnector fails to close within a preset time after the disconnector closing command is sent, a power-on failure message will be reported.

14. The method according to any one of claims 1-13, characterized in that, The method further includes: Upon receiving a high-voltage power-off command, a disconnector switch opening command is sent to the disconnector switch driving device. The disconnector switch opening command is used to instruct the disconnector switch driving device to control the disconnector switch to open. The control unit disconnects the battery clusters in the high-voltage circuit from the high-voltage bus.

15. The method according to claim 14, characterized in that, The conditions for generating the high-voltage power-down command include at least one of the following: During the high-voltage energization process, the disconnecting switch failed to close within the preset time period; After closing the precharge switch and the main negative switch, the voltage difference across the main positive switch does not fall below the first preset voltage difference within a preset time period; The battery management system detected a fault in the energy storage system.

16. A battery management system, characterized in that, The battery management system includes a battery management controller, which is used to send a disconnector closing command to the disconnector drive device when it is determined that the high voltage power-on conditions are met. The disconnector closing command is used to instruct the disconnector drive device to control the disconnector to close. The disconnecting switch is located between the battery clusters and the high-voltage bus of the energy storage system; and, when the disconnecting switch is closed, the battery clusters to be powered on in the energy storage system are controlled to be powered on.

17. The battery management system according to claim 16, characterized in that, The battery management controller includes a primary controller and a secondary controller. Each secondary controller is used to control the electrical components on the corresponding branch where the battery cluster is located. The primary controller is communicatively connected to the secondary controller and is also communicatively connected to the disconnect switch drive device.

18. An energy storage system, characterized in that, The battery cluster and battery management system, the disconnect switch drive device and the disconnect switch; The disconnecting switch is installed on the high-voltage bus of the energy storage system, and the disconnecting switch driving device is used to drive the disconnecting switch to open or close. The battery management system is communicatively connected to the disconnect switch drive device and the battery cluster; The battery management system is used to perform the method as described in any one of claims 1-15.

19. The energy storage system according to claim 18, characterized in that, The disconnector drive device includes an electric operating mechanism, which provides the required force or power to the disconnector so that the disconnector can perform opening or closing operations as required.

20. The energy storage system according to claim 18 or 19, wherein each branch containing the battery cluster includes a pre-charge circuit; The precharge circuit includes a precharge switch and a precharge resistor, wherein, The precharge switch is used to precharge the battery cluster through the precharge circuit before the main positive switch is closed; the precharge resistor is used to precharge the battery cluster after the precharge switch is closed.

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