Energy storage system and control method thereof

Abstract

The application discloses an energy storage system and a control method thereof, and relates to the technical field of energy storage. The energy storage system comprises an energy conversion controller and at least one battery pack. The energy conversion controller comprises a power conversion unit and a communication unit. The energy conversion controller realizes bidirectional energy conversion between alternating current of a power grid and direct current of the battery pack through the power conversion unit. The energy conversion controller communicates with the battery pack through the communication unit and controls the running state of the battery pack. Each battery pack comprises a battery group, a charge-discharge control switch and an acquisition and balancing unit. The energy conversion controller controls the on-off of the charge-discharge control switch and then controls the charge-discharge state of the battery group. The acquisition and balancing unit is used for acquiring current, voltage and temperature information of the battery pack and sending the information to the communication unit. The energy storage system according to the embodiment of the application can flexibly cope with different voltage requirements and capacity requirements of the energy storage system, has good compatibility and strong fault tolerance.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to an energy storage system and its control method. Background Technology

[0002] Existing electrochemical energy storage and power supply systems typically put the entire battery pack into operation simultaneously. However, due to the special requirements for the consistency of lithium batteries, the failure of one battery pack will lead to the failure of the entire battery pack, resulting in poor fault tolerance and reliability of the system. At the same time, the system's scalability and flexibility are also relatively poor. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a highly reliable energy storage system and its control method.

[0004] On one hand, an energy storage system according to an embodiment of the present invention includes: an energy conversion controller, comprising a power conversion unit and a communication unit, wherein the energy conversion controller realizes bidirectional energy conversion between AC power from the power grid and DC power from a battery pack through the power conversion unit, and the energy conversion controller communicates with the battery pack through the communication unit and controls the operating state of the battery pack; at least one battery pack, the battery pack comprising a battery group, a charge / discharge control switch and a data acquisition and equalization unit, wherein the energy conversion controller controls the charge / discharge state of the battery group by controlling the on / off state of the charge / discharge control switch; and the data acquisition and equalization unit is used to acquire current, voltage and temperature information of each cell in the battery group and send it to the communication unit.

[0005] According to some embodiments of the present invention, the battery pack is provided with a communication interface, the acquisition equalization unit is electrically connected to the communication interface, and the communication interface is electrically connected to the communication unit through a communication bus.

[0006] According to some embodiments of the present invention, the battery pack is provided with a power interface, the battery group is electrically connected to the power interface through the charge / discharge control switch, and the power interface is electrically connected to the DC side of the energy conversion controller through a power bus.

[0007] According to some embodiments of the present invention, the battery pack is provided with a main control switch.

[0008] According to some embodiments of the present invention, the energy conversion controller further includes a display unit for displaying the operating information of the energy storage system.

[0009] According to some embodiments of the present invention, the energy conversion controller further includes an operation unit for setting or modifying the operating parameters of the energy storage system.

[0010] The energy storage system according to embodiments of the present invention has at least the following beneficial effects: The energy conversion controller, through a power conversion unit, can realize bidirectional energy conversion between AC power from the power grid and DC power from the battery pack; simultaneously, the energy conversion controller can communicate with the battery pack through a communication unit. The data acquisition and equalization unit can monitor the current, voltage, and temperature of each individual cell in the battery pack in real time and send it to the communication unit, enabling the energy conversion controller to acquire data from the battery pack. Based on the processing and calculation results of the large data, it can generate commands such as control, warning, alarm, and maintenance, and control the state of the battery pack's charge / discharge control switch, thereby achieving power control of the battery pack, effectively preventing excessive charge / discharge current, and improving the usable capacity and service life of the battery pack. When a battery pack malfunctions, the energy conversion controller can disconnect the charge / discharge control switch of that battery pack, causing it to exit the energy storage system without affecting the normal operation of the energy storage system. This energy storage system exhibits strong fault tolerance, reliability, and flexibility.

[0011] On the other hand, the address allocation method for an energy storage system according to an embodiment of the present invention includes the following steps:

[0012] The battery pack sends a first message to the energy conversion controller requesting address allocation; wherein the first message includes a first identifier of the battery pack;

[0013] After receiving the first message, the energy conversion controller allocates an idle execution address to the battery pack and sends a second message to the battery pack; wherein, the second message includes the execution address;

[0014] After receiving the second message, the battery pack writes the identifier of the execution address, and after successful configuration, sends a third message to the energy conversion controller.

[0015] After receiving the third message, the energy conversion controller saves the configuration information and completes the address allocation.

[0016] According to some embodiments of the present invention, the method further includes the following steps:

[0017] The battery pack monitors the communication bus in real time to determine if there are any address conflicts.

[0018] When an address conflict is detected, the process returns to the step where the battery pack sends a first message to the energy conversion controller requesting address allocation.

[0019] According to some embodiments of the present invention, the method further includes the following steps:

[0020] The energy conversion controller broadcasts a heartbeat signal to all battery packs in the energy storage system.

[0021] When the battery pack does not detect the heartbeat signal within a preset time, the battery pack disconnects from the power bus.

[0022] The address allocation method for the energy storage system according to the embodiments of the present invention has at least the following advantages: the energy conversion controller can automatically allocate new addresses to the battery pack, preventing address conflicts from occurring. The process is simple, convenient, and highly efficient.

[0023] On the other hand, the battery pack charging method according to an embodiment of the present invention includes the following steps:

[0024] When a new battery pack is added to the energy storage system, the energy conversion controller adjusts the charging power to a first power and adjusts the charging voltage to match the voltage of the power bus; wherein, the first power is less than the rated power of the energy conversion controller;

[0025] The pre-charging circuit and charge / discharge control switch of the battery pack are turned on to replenish power;

[0026] When the difference between the voltage of the battery pack and the voltage of the power bus is less than a first threshold, the power replenishment is completed, and the charging power and charging voltage of the energy conversion controller are restored.

[0027] The battery pack recharging method according to embodiments of the present invention has at least the following beneficial effects: the energy conversion controller can automatically recharge newly added battery packs, enabling the newly added battery packs to operate normally.

[0028] On the other hand, the control method for an energy storage system according to an embodiment of the present invention includes the following steps:

[0029] When a new battery pack is to be added to the energy storage system, the address allocation method of the energy storage system as described in the above embodiments of the present invention is executed to allocate an address to the new battery pack.

[0030] When there is already an online battery pack in the energy storage system, if the voltage of the new battery pack is less than the voltage of the power bus, and the difference between the voltage of the new battery pack and the voltage of the power bus is greater than or equal to a first threshold, then the battery pack charging method described in the above embodiments of the present invention is executed to charge the new battery pack.

[0031] The new battery pack is put into operation when the difference between the voltage of the new battery pack and the voltage of the power bus is less than the first threshold.

[0032] The control method for the energy storage system of the battery pack according to the embodiments of the present invention has at least the following beneficial effects: it can automatically assign new addresses to newly added battery packs to prevent address conflicts, and the process is simple, convenient, and highly efficient; at the same time, it can select appropriate control strategies based on the status information of newly added battery packs to enable the battery packs to be put into normal operation and ensure the normal operation of the energy storage system.

[0033] On the other hand, the emergency operation method of the energy storage system according to an embodiment of the present invention includes the following steps:

[0034] After all the battery packs in the energy storage system are powered on, press the main control switch of one of the battery packs to make the battery pack work in stand-alone mode, and the battery pack provides working power to the energy conversion controller.

[0035] After the energy conversion controller is started, it executes the address allocation method of the energy storage system as described in the second aspect embodiment, and allocates addresses to battery packs other than those in stand-alone mode.

[0036] The energy conversion controller acquires the voltage information of each battery pack and puts the battery pack with the highest voltage, which is higher than the voltage of the battery pack in stand-alone mode, into operation. The battery packs that are not in operation are in a waiting state.

[0037] The energy storage system discharges to the load, causing the voltage of the power bus to drop. When the difference between the voltage of the battery pack in the waiting state and the voltage of the power bus is less than a first threshold, the battery pack is put into operation.

[0038] The emergency operation method of the energy storage system according to the embodiments of the present invention has at least the following beneficial effects: in the event of a power grid outage, the energy storage system can use one of its battery packs as an emergency power source to provide power for the normal operation of the energy storage system, thereby ensuring that the energy storage system can supply power to the load normally and improving the reliability and flexibility of the energy storage system.

[0039] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0040] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0041] Figure 1 This is a schematic diagram of the circuit principle of the energy storage system according to an embodiment of the present invention;

[0042] Figure 2 This is a flowchart illustrating the steps of the address allocation method for an energy storage system according to an embodiment of the present invention.

[0043] Figure 3 This is a flowchart of the steps of the battery pack charging method according to an embodiment of the present invention;

[0044] Figure 4 This is a flowchart illustrating the steps of a control method for an energy storage system according to an embodiment of the present invention.

[0045] Figure 5 This is a flowchart illustrating the steps of an emergency operation method for an energy storage system according to an embodiment of the present invention.

[0046] Figure label:

[0047] Energy conversion controller 100, power conversion unit 110, communication unit 120, display unit 130, operation unit 140;

[0048] Battery pack 200, battery group 210, charge / discharge control switch 220, data acquisition and equalization unit 230, communication interface 240, communication bus 250, power interface 260, power bus 270, main control switch 280. Detailed Implementation

[0049] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0050] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0051] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0052] On the one hand, such as Figure 1As shown, the energy storage system according to an embodiment of the present invention includes an energy conversion controller 100 and at least one battery pack 200 (when there are multiple battery packs 200, the multiple battery packs 200 are connected in parallel); wherein, the energy conversion controller 100 includes a power conversion unit 110 and a communication unit 120, the AC side of the energy conversion controller 100 is connected to the power grid, the energy conversion controller 100 realizes bidirectional energy conversion between the AC power of the power grid and the DC power of the battery pack 200 through the power conversion unit 110, the energy conversion controller 100 communicates with the battery pack 200 through the communication unit 120 and controls the operating state of the battery pack 200; each battery pack 200 includes a battery group 210, a charge / discharge control switch 220 and a data acquisition and equalization unit 230, the energy conversion controller 100 controls the charge / discharge state of the battery group 210 by controlling the on / off state of the charge / discharge control switch 220; the data acquisition and equalization unit 230 is used to collect the current, voltage and temperature information of the battery pack 200 and send it to the communication unit 120.

[0053] Specifically, in the energy storage system according to an embodiment of the present invention, the power conversion unit 110 is a power device for bidirectional energy conversion between the AC power of the power grid and the DC power of the battery pack 200. The communication unit 120 is mainly responsible for the communication of data and control commands between the energy conversion controller 100 and the battery pack 200. The energy conversion controller 100 has built-in control strategy management and has operating modes such as backup power, power limiting, peak shaving and valley filling, and power quality management. The battery pack 210 is composed of multiple cells connected in series / parallel. The data acquisition and balancing unit 230 can monitor the current, voltage, and temperature of each individual cell in the battery pack 210 in real time and has a voltage balancing function. Through an efficient balancing strategy, the consistency of the battery pack 210 is well maintained. The data acquisition and equalization unit 230 can collect information such as current, voltage, and temperature of individual cells in the battery pack 210 and send it to the communication unit 120. This allows the energy conversion controller 100 to obtain data from the battery pack 200 and, based on the data processing and calculation results, generate commands such as control, warning, alarm, and maintenance, as well as control the state of the charge / discharge control switch 220 of the battery pack 200. This achieves power control of the battery pack 210, effectively preventing excessive charge / discharge current and improving the usable capacity and lifespan of the battery pack 200. When a battery pack 200 malfunctions, the energy conversion controller 100 can disconnect the charge / discharge control switch 220 of that battery pack, causing it to exit the energy storage system without affecting the normal operation of the energy storage system. This demonstrates the strong fault tolerance, reliability, and flexibility of the energy storage system.

[0054] like Figure 1As shown, in some embodiments of the present invention, the battery pack 200 is provided with a communication interface 240, the acquisition and equalization unit 230 is electrically connected to the communication interface 240, and the communication interface 240 is electrically connected to the communication unit 120 through the communication bus 250. The acquisition and equalization unit 230 communicates with the energy conversion controller 100 through the communication interface 240 and the communication bus 250, so that the energy conversion controller 100 can collect information from each battery pack 200 and control the operating status of each battery pack 200 to ensure that each battery pack 200 can operate safely.

[0055] More specifically, in some embodiments of the present invention, the communication interface 240 is a quick-plug interface, which makes the installation and removal of the battery pack 200 faster and more convenient; the communication bus 250 is a CAN2.0 high-speed bus (or other common buses), and the communication nodes of all battery packs 200 are connected together and connected to the communication interface of the energy conversion controller 100 to realize communication between the battery pack 200 and the energy conversion controller 100.

[0056] In some embodiments of the present invention, the battery pack 200 is provided with a power interface 260. The battery group 210 is electrically connected to the power interface 260 via a charge / discharge control switch 220. The power interface 260 is electrically connected to the DC side of the energy conversion controller 100 via a power bus 270. The electrical energy output by the battery group 210, after passing through the charge / discharge control switch 220, flows through the power interface 260 and into the power bus 270, thereby connecting to the DC side of the energy conversion controller 100. The energy conversion controller 100 can control the charging and discharging of the battery group 210 by controlling the charge / discharge control switch 220, preventing excessive charging and discharging current and improving the service life of the battery pack 200.

[0057] More specifically, in some embodiments of the present invention, the power interface 260 adopts a female socket with a plug-in structure containing positive and negative power terminals, which can be quickly and directly plugged in and out with the male plug, facilitating the use and removal of the battery pack 200.

[0058] like Figure 1 As shown, in some embodiments of the present invention, the battery pack 200 is equipped with a main control switch 280. When the main control switch 280 is pressed, the battery pack 200 can operate independently without communication, directly outputting electrical energy to meet certain occasions where the battery pack 200 needs to be used temporarily. After the battery pack 200 is used up, it can be reinserted into any position in the energy storage system, connected to the communication interface 240 and power interface 260 on the battery pack 200, and the power button can be pressed. The energy storage system can then automatically assign a new address to the battery pack 200, and the system can be put back into use according to the operating strategy.

[0059] like Figure 1As shown, in some embodiments of the present invention, the energy conversion controller 100 further includes a display unit 130, which is used to display the operating status, various parameters, curves, alarms, historical information, etc. of the energy storage system, such as the battery pack 200.

[0060] like Figure 1 As shown, in some embodiments of the present invention, the energy conversion controller 100 further includes an operation unit 140, which is used to set or modify the operating parameters of the energy storage system and provide functions such as modification authorization password verification.

[0061] The energy storage system according to embodiments of the present invention has the following advantages:

[0062] 1) Supports power control for each battery pack 200, effectively preventing excessive charging and discharging current of the battery pack 200, and improving the usable capacity and service life of the battery pack 200.

[0063] 2) Modular design with strong expandability, capable of flexibly meeting different voltage requirements and energy storage system capacity requirements;

[0064] 3) Rack-mount structure with quick-plug interfaces for faster and more convenient installation and disassembly;

[0065] 4) The system has good compatibility; the installation positions of any 200 battery pack can be interchanged and freely combined.

[0066] 5) Strong fault tolerance; if any 200 battery pack is damaged, it can automatically exit without affecting system operation.

[0067] 6) Each battery pack 200 can identify its own status and automatically assign addresses, making it flexible in application.

[0068] The energy storage system according to an embodiment of the present invention has overall transportation and mobility capabilities, and the battery pack 200 can be flexibly combined between different systems. When a battery pack 200 needs to be removed, press the power off button on the battery pack 200. After the battery pack 200 is powered off, unplug the communication connector and power plug on the battery pack 200 to remove it. After the battery pack 200 is no longer in use, it can be reinserted into any position in the energy storage system. Connect the communication connector and power plug on the battery pack 200, press the power on button, and the energy storage system can automatically assign a new address to the battery pack, and the system can be put back into use according to the operating strategy. At the same time, the energy conversion controller 100 can automatically identify faulty batteries. When the percentage of a single battery cell is less than 90% of the average value of the same battery pack 210 (the specific value can be customized, such as 85%, 95%, etc.), it provides maintenance suggestions; when it is less than 80% (the specific value can be set, such as 70%, 75%, etc.), it provides replacement suggestions. When any battery pack 200 fails, it automatically shuts down and sends specific fault information to the energy conversion controller 100, which displays and saves the information on the display unit 130. In applications with 48V DC loads such as road rescue and communication base stations, any battery pack 200 can be used independently. After powering on, pressing the main control switch 280 of the battery pack allows it to directly output a 48V voltage source to the load.

[0069] On the other hand, such as Figure 2 As shown, the address allocation method for an energy storage system according to an embodiment of the present invention includes the following steps:

[0070] Step S100: The battery pack 200 sends a first message requesting address allocation to the energy conversion controller 100; wherein the first message includes a first identifier of the battery pack 200.

[0071] Specifically, after the battery pack 200 is powered on and performs a normal self-test, it obtains the unique identifier UUID (Universally Unique Identifier) ​​of the main control chip, which is the first identifier mentioned above. Then, the battery pack 200 sends a first message requesting address allocation to the energy conversion controller 100. The frame ID is fixed at 18FFFFFF (which can be customized), and the data is the UUID conversion value.

[0072] Step S200: After receiving the first message, the energy conversion controller 100 allocates an idle execution address to the battery pack 200 and sends a second message to the battery pack 200; wherein, the second message includes the execution address.

[0073] Specifically, after receiving the first message requesting address allocation, the energy conversion controller 100 automatically allocates an idle address number based on the current online operation status of the battery pack 200 in the energy storage system, and sends a second message containing the execution address to the battery pack 200. The frame ID of the second message is a UUID conversion value, and the data is the allocated address number.

[0074] Step S300: After receiving the second message, the battery pack 200 writes the identifier of the execution address, and after successful configuration, sends the third message to the energy conversion controller 100.

[0075] Specifically, after receiving the second message of the execution address, the battery pack 200 writes the identifier of the execution address. If the configuration is successful, it sends a configuration success message, i.e., the third message, to the energy conversion controller 100; otherwise, it returns to step S100.

[0076] Step S400: After receiving the third message, the energy conversion controller 100 saves the configuration information and completes the address allocation.

[0077] Specifically, after receiving the feedback information that the configuration is successful, the energy conversion controller 100 saves the configuration and completes the address allocation.

[0078] In some embodiments of the present invention, the address allocation method for the energy storage system further includes the following steps:

[0079] Step S500: The battery pack 200 monitors the communication bus 250 in real time to determine if there is an address conflict;

[0080] Step S600: If an address conflict is determined to exist, return to step S100.

[0081] Specifically, during the address allocation process of the battery pack 200, the battery pack 200 will monitor the communication bus 250 in real time to check for address conflicts. If an address conflict is found, it will return to step S100; otherwise, the address allocation is completed.

[0082] In some embodiments of the present invention, the address allocation method for the energy storage system further includes the following steps:

[0083] Step S700: The energy conversion controller 100 broadcasts a heartbeat signal to all battery packs 200 of the energy storage system;

[0084] Step S800: When the battery pack 200 does not detect a heartbeat signal within a preset time, the battery pack 200 disconnects from the power bus 270.

[0085] Specifically, during the operation of the energy storage system, the energy conversion controller 100 broadcasts a heartbeat signal to all battery packs 200. If a battery pack 200 in normal operation does not detect a heartbeat signal within a preset time (e.g., 1 second or another value), it is considered that the communication is interrupted, and the battery pack 200 will disconnect from the power bus 270 and exit operation. If the battery pack 200 can detect the heartbeat signal again, it checks whether there is an address conflict on the communication bus 250. If so, it returns to step S100; otherwise, normal communication is restored, and normal operation resumes.

[0086] The address allocation method of the energy storage system according to the embodiment of the present invention can automatically allocate new addresses to the battery pack 200, prevent address conflicts, and the process is simple, convenient and efficient.

[0087] On the other hand, such as Figure 3 As shown, the battery pack charging method according to an embodiment of the present invention includes the following steps:

[0088] Step S100a: When a new battery pack 200 is added to the energy storage system, the energy conversion controller 100 adjusts the charging power to a first power and adjusts the charging voltage to match the voltage of the power bus 270; wherein, the first power is lower than the rated power of the energy conversion controller 100.

[0089] Specifically, assuming that after adding a new battery pack 200 to the energy storage system, there are a total of 16 battery packs 200, the charging power of the energy conversion controller 100, i.e., the first power, can be adjusted to 1 / 16 of the rated power, and the charging voltage can be made consistent with the voltage of the power bus 270 to prevent charging of other online battery packs 200. The first power is adjusted according to the specific number of battery packs 200.

[0090] Step S200a: The pre-charging circuit and charge / discharge control switch 220 of the battery pack 200 are turned on to replenish power.

[0091] Specifically, the battery pack 200 activates the pre-charging circuit to pre-charge, avoiding instantaneous current surges; at the same time, the charge and discharge control switch 220 of the battery pack 200 is turned on, and the energy conversion controller 100 replenishes the battery pack 200.

[0092] Step S300a: When the difference between the voltage of the battery pack 200 and the voltage of the power bus 270 is less than the first threshold, the charging is completed, and the charging power and charging voltage of the energy conversion controller 100 are restored.

[0093] Specifically, the first threshold can be set to 0.5V or other reasonable values. When the difference between the voltage of the newly added battery pack 200 and the voltage of the power bus 270 is less than 0.5V, the power and voltage parameters of the energy conversion controller 100 are restored to complete the power replenishment.

[0094] The battery pack replenishment method of the energy storage system according to the present invention can automatically replenish the newly added battery pack 200, so that the newly added battery pack 200 can be put into normal operation.

[0095] On the other hand, such as Figure 4 As shown, the control method for an energy storage system according to an embodiment of the present invention includes the following steps:

[0096] Step S100b: When a new battery pack 200 is to be added to the energy storage system, the address allocation method of the energy storage system described above is executed to allocate an address to the new battery pack 200.

[0097] Step S200b: When there is already an online battery pack 200 in the energy storage system, if the voltage of the new battery pack 200 is less than the voltage of the power bus 270, and the difference between the voltage of the new battery pack 200 and the voltage of the power bus 270 is greater than or equal to the first threshold, then the above-mentioned battery pack charging method is executed to charge the new battery pack 200.

[0098] Step S300b: When the difference between the voltage of the new battery pack 200 and the voltage of the power bus 270 is less than the first threshold, the new battery pack 200 is put into operation.

[0099] Specifically, when a new battery pack 200 needs to be added to the energy storage system, the address allocation method of the energy storage system described above is executed, automatically assigning an address to the new battery pack 200. Then, the energy conversion controller 100 communicates with the battery pack 200 to confirm that the status information of the battery pack 200 is normal; subsequently, the energy conversion controller 100 detects the number of battery packs 200 online in the energy storage system. If no battery pack 200 is online, the newly added battery pack 200 is put into operation directly. If a battery pack 200 is already online and the voltage difference between the newly added battery pack 200 and the voltage of the power bus 270 is less than a first threshold (0.5V or other value), the newly added battery pack 200 is put into operation directly. If the voltage difference between the newly added battery pack 200 and the power bus 270 is greater than or equal to a first threshold, and the voltage of the newly added battery pack 200 is less than the voltage of the power bus 270, then the battery pack charging method described above is executed to charge the new battery pack 200; once the voltage difference between the new battery pack 200 and the power bus 270 is less than the first threshold, the new battery pack 200 is put into operation. If the voltage difference between the newly added battery pack 200 and the power bus 270 is greater than or equal to the first threshold, and the voltage of the newly added battery pack 200 is greater than the voltage of the power bus 270, then the newly added battery pack 200 enters a waiting state, waiting for the online battery pack 200 to charge, until the voltage difference between the newly added battery pack 200 and the power bus 270 is less than the first threshold, then the new battery pack 200 is put into operation.

[0100] The control method for the energy storage system according to the embodiments of the present invention can automatically assign a new address to the newly added battery pack 200 to prevent address conflicts. The process is simple, convenient, and highly efficient. At the same time, it can select an appropriate control strategy based on the status information of the newly added battery pack 200, so that the battery pack 200 can be put into normal operation and the energy storage system can operate normally.

[0101] On the other hand, such as Figure 5 As shown, the emergency operation method of the energy storage system according to an embodiment of the present invention includes the following steps:

[0102] Step S100c: After all the battery packs 200 in the energy storage system are powered on, press the main control switch 280 of one of the battery packs 200 to make the battery pack 200 work in stand-alone mode, and the battery pack 200 provides working power to the energy conversion controller 100.

[0103] Specifically, in the event of a power grid outage, the energy storage system can use one of the battery packs 200 as an emergency power source to provide power for the normal operation of the energy storage system. To this end, after all the battery packs 200 are powered on, any one of the battery packs 200 can be selected as an emergency power source, and its main control switch 280 can be pressed to put it into stand-alone mode, providing power to the energy conversion controller 100.

[0104] Step S200c: After the energy conversion controller 100 starts, it executes the above-mentioned address allocation method for the energy storage system to allocate addresses to other battery packs 200 except for the battery pack 200 in stand-alone mode.

[0105] Step S300c: The energy conversion controller 100 acquires the voltage information of each battery pack 200 and puts the battery pack 200 with the highest voltage and a voltage higher than that of the battery pack 200 in stand-alone mode into operation. The battery packs 200 that are not in operation are in a waiting state.

[0106] Step S400c: The energy storage system discharges to the load, causing the voltage of the power bus 270 to drop. When the difference between the voltage of the battery pack 200 in the waiting state and the voltage of the power bus 270 is less than the first threshold, the battery pack 200 is put into operation.

[0107] Specifically, once the energy conversion controller 100 is in normal startup state, it assigns addresses to all remaining battery packs 200. Simultaneously, the energy conversion controller 100 collects voltage information from each battery pack 200. When the total voltage of any battery pack 200 is greater than or equal to the voltage of a battery pack 200 in standalone mode, the energy conversion controller 100 sends a start-up command to the battery pack 200 with the highest voltage. The battery pack 200 with the highest voltage then starts operating and discharges to the load, while the remaining battery packs 200 enter a waiting state. If the voltage of a battery pack 200 in standalone mode is the highest, the energy storage system directly discharges to the load, and all other battery packs 200 enter a waiting state. As the energy storage system discharges, the voltage of the power bus 270 decreases until the difference between the voltage of the non-operational battery packs 200 and the voltage of the power bus is less than a first threshold. Then, the non-operational battery packs 200 are sequentially started operating.

[0108] The emergency operation method of the energy storage system according to the embodiments of the present invention can ensure that the energy storage system can supply power to the load normally in the event of a power grid failure, thereby improving the reliability and flexibility of the energy storage system.

[0109] In the description of this specification, references to terms such as "one embodiment," "further embodiment," "some specific embodiments," or "some examples," etc., indicate that a specific feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0110] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An emergency operation method for an energy storage system, characterized in that, The energy storage system includes: an energy conversion controller, comprising a power conversion unit and a communication unit; the energy conversion controller realizes bidirectional energy conversion between AC power from the power grid and DC power from the battery pack through the power conversion unit; the energy conversion controller communicates with the battery pack through the communication unit and controls the operating state of the battery pack; at least one battery pack, the battery pack comprising a battery array, a charge / discharge control switch, and a data acquisition and equalization unit; the energy conversion controller controls the charge / discharge state of the battery array by controlling the on / off state of the charge / discharge control switch; the data acquisition and equalization unit is used to collect current, voltage, and temperature information of each cell in the battery array and send it to the communication unit; the method includes the following steps: After all the battery packs in the energy storage system are powered on, press the main control switch of one of the battery packs to make the battery pack work in stand-alone mode, and the battery pack provides working power to the energy conversion controller. After the energy conversion controller is started, it executes the address allocation method of the energy storage system to allocate addresses to other battery packs except those in stand-alone mode. The energy conversion controller acquires the voltage information of each battery pack and puts the battery pack with the highest voltage, which is higher than the voltage of the battery pack in stand-alone mode, into operation. The battery packs that are not in operation are in a waiting state. The energy storage system discharges to the load, causing the voltage of the power bus to drop. When the difference between the voltage of the battery pack in the waiting state and the voltage of the power bus is less than a first threshold, the battery pack is put into operation. The address allocation method for the energy storage system includes the following steps: The battery pack sends a first message to the energy conversion controller requesting address allocation; wherein the first message includes a first identifier of the battery pack; After receiving the first message, the energy conversion controller allocates an idle execution address to the battery pack and sends a second message to the battery pack; wherein, the second message includes the execution address; After receiving the second message, the battery pack writes the identifier of the execution address, and after successful configuration, sends a third message to the energy conversion controller. After receiving the third message, the energy conversion controller saves the configuration information and completes the address allocation.

2. The emergency operation method for the energy storage system according to claim 1, characterized in that, The address allocation method for the energy storage system further includes the following steps: The battery pack monitors the communication bus in real time to determine if there are any address conflicts. When an address conflict is identified, the process returns to the step where the battery pack sends a first message to the energy conversion controller requesting address allocation.

3. The emergency operation method for the energy storage system according to claim 1, characterized in that, The address allocation method for the energy storage system further includes the following steps: The energy conversion controller broadcasts a heartbeat signal to all battery packs in the energy storage system. When the battery pack does not detect the heartbeat signal within a preset time, the battery pack disconnects from the power bus.

4. The emergency operation method for the energy storage system according to claim 1, characterized in that, The battery pack is provided with a communication interface, the acquisition and equalization unit is electrically connected to the communication interface, and the communication interface is electrically connected to the communication unit through a communication bus.

5. The emergency operation method of the energy storage system according to claim 1, characterized in that, The battery pack is provided with a power interface, and the battery group is electrically connected to the power interface through the charge and discharge control switch. The power interface is electrically connected to the DC side of the energy conversion controller through a power bus.

6. The emergency operation method for the energy storage system according to claim 1, characterized in that, The battery pack is equipped with a main control switch.

7. The emergency operation method of the energy storage system according to claim 1, characterized in that, The energy conversion controller also includes a display unit, which is used to display the operating information of the energy storage system.

8. The emergency operation method of the energy storage system according to claim 1, characterized in that, The energy conversion controller also includes an operation unit, which is used to set or modify the operating parameters of the energy storage system.

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