Battery cluster direct current distribution energy storage system and control method thereof

Abstract

The invention provides a battery cluster direct current power distribution energy storage system and a control method thereof. The battery cluster direct-current power distribution energy storage system comprises a battery cluster (1) which is connected into a high-voltage direct-current bus (3) through a first circuit breaker (2); the DCDC module (4) is connected to the high-voltage direct-current bus (3) in parallel, a low-voltage direct-current bus (5) is constructed at the end, away from the high-voltage direct-current bus (3), of the DCDC module (4), and a second circuit breaker (6) is arranged at the end, connected with the DCDC module (4), of the low-voltage direct-current bus (5); the control load is connected to the low-voltage direct-current bus (5) and is positioned at one end, far away from the DCDC module (4), of the second circuit breaker (6); and the energy storage converter (7) is connected into the high-voltage direct-current bus (3). According to the battery cluster direct-current power distribution energy storage system, the power utilization efficiency of the energy storage system during off-grid operation can be improved.

Description

Technical Field

[0001] This invention relates to the field of energy storage system technology, and more specifically, to a battery cluster DC power distribution energy storage system and its control method. Background Technology

[0002] Energy storage systems mainly consist of energy storage cells and a battery management system (BMS), a power conversion system (PCS), and an energy management system (EMS). Conventional energy storage systems are mostly grid-connected and used to store large amounts of electrical energy and continuously discharge and charge at low power, thereby achieving the purpose of peak shaving and valley filling for the large power grid and smoothing grid fluctuations.

[0003] However, in many overseas microgrid energy storage application scenarios, the energy storage system needs to operate off-grid, meaning that the energy storage system builds its own voltage source without the support of an external power source. Current energy storage systems in microgrid applications face the following problems:

[0004] Current energy storage systems are all grid-connected, meaning they connect to the power grid and profit from the price difference by charging during off-peak hours and discharging during peak hours. The entire system's control power comes from the AC grid, making it highly dependent on it. When an AC-powered energy storage system is used off-grid, a system failure causing the PCS (Power Control System) to shut down results in no AC power. The entire control system must rely on an Uninterruptible Power Supply (UPS) for power, which typically lasts only about two hours. At night or on holidays, if maintenance personnel cannot quickly reach the site, the energy storage system's control equipment cannot start, leading to the awkward situation where the energy storage batteries are charged, but the control equipment is without power.

[0005] When energy storage devices are off-grid, the traditional method of drawing power from the AC side for control will consume the output power of the PCS, reducing the ability of the energy storage system to output power to equipment such as tower cranes and electromechanical equipment when operating off-grid.

[0006] When energy storage devices are off-grid, the traditional method of drawing power from the AC side for control equipment keeps the PCS (Power Control System) constantly running, meaning there is always a load on the AC side. The energy consumption ratio of a high-power power supply like the PCS under load versus in standby (no load) state can be as high as tens of times. Therefore, drawing power from the AC side will rapidly consume the energy of the energy storage system, causing the power loss of the entire energy storage system to rise sharply, the power efficiency to drop significantly, and the system to lose its economic viability.

[0007] Therefore, existing energy storage systems suffer from the problem that their power consumption efficiency cannot be effectively utilized when operating off-grid. Summary of the Invention

[0008] The main objective of this invention is to provide a battery cluster DC power distribution energy storage system and its control method, which can improve the power consumption efficiency of the energy storage system when it is operating off-grid.

[0009] To achieve the above objectives, according to one aspect of the present invention, a battery cluster DC power distribution and energy storage system is provided, comprising:

[0010] The battery cluster is connected to the high-voltage DC bus via the first circuit breaker;

[0011] The DC-DC module is connected in parallel to the high-voltage DC bus. A low-voltage DC bus is built at the end of the DC-DC module away from the high-voltage DC bus. A second circuit breaker is installed at the end of the low-voltage DC bus connected to the DC-DC module.

[0012] The control load is connected to the low-voltage DC bus and is located at the end of the second circuit breaker furthest from the DC-DC module;

[0013] The energy storage converter is connected to the high-voltage DC bus.

[0014] Furthermore, a backup battery is installed between the DC-DC module and the second circuit breaker. The backup battery is connected to the low-voltage DC bus and is connected in parallel with the DC-DC module.

[0015] Furthermore, the control terminal of the first circuit breaker is connected to the control load.

[0016] Furthermore, the battery cluster DC power distribution energy storage system also includes an ACDC module and an automatic transfer switch. The automatic transfer switch is connected to the output of the DCDC module, the DCDC module is connected to the main power of the automatic transfer switch, and the ACDC module is connected between the auxiliary power of the automatic transfer switch and the energy storage converter.

[0017] Furthermore, the battery cluster DC power distribution energy storage system also includes an undervoltage protector, which is connected to the low-voltage DC bus to collect the voltage of the low-voltage DC bus and upload undervoltage information when the collected voltage is lower than a set threshold.

[0018] Furthermore, the control load includes a core load and a secondary load. The core load includes an energy management system and a contactor is installed on the low-voltage DC bus. The secondary load is electrically connected to the backup battery through the contactor. When the backup battery supplies power to the control load, the energy management system controls the contactor to open when the undervoltage protector detects that the voltage of the low-voltage DC bus has reached the secondary threshold, and controls the second circuit breaker to open when the undervoltage protector detects that the voltage of the low-voltage DC bus has reached the primary threshold.

[0019] Furthermore, the control load includes a fire protection system, which includes a water pump and a water tank. The water tank contains coolant, and the water pump is used to pump the coolant from the water tank. The water pump is connected to each battery pack in the battery cluster through multiple liquid cooling pipes, and each liquid cooling pipe is equipped with an electrically controlled valve.

[0020] According to another aspect of the present invention, a control method for the above-described battery cluster DC power distribution energy storage system is provided, comprising:

[0021] Check whether the energy storage system is operating off-grid;

[0022] When the energy storage system is off-grid, detect whether the energy storage system has malfunctioned.

[0023] When a fault occurs in the energy storage system, determine whether the fault is a battery cluster fault;

[0024] When the fault is not a battery cluster fault, the first and second circuit breakers are closed, and the battery cluster supplies power to the control load through the DC-DC module.

[0025] Furthermore, the control methods also include:

[0026] When the fault is a battery cluster fault, the first circuit breaker is opened and the second circuit breaker is closed.

[0027] The backup battery supplies power to the control load via the low-voltage DC bus.

[0028] Furthermore, the control methods also include:

[0029] When the fault is a battery cluster fault, determine the fault type;

[0030] When the fault type is a fire alarm, the backup battery continues to supply power, and the energy management system controls the fire system to spray until the backup battery is depleted.

[0031] When the fault type is fire-fighting thermal runaway, the energy management system identifies the thermal runaway cell number and determines the battery pack location of the corresponding cell.

[0032] Powered continuously by backup batteries, the energy management system controls the fire suppression system to inject coolant into the battery packs at the appropriate locations, submerging them.

[0033] Furthermore, the control methods also include:

[0034] Check the voltage of the backup battery;

[0035] When the voltage of the backup battery is greater than or equal to the secondary threshold, control the backup battery to supply power to all control loads;

[0036] When the voltage of the backup battery is greater than the first threshold and less than the second threshold, a dry contact signal is output to the energy management system. The energy management system controls the contactor to open, and the secondary load is isolated from the backup battery. The backup battery only supplies power to the core load.

[0037] When the voltage of the backup battery is less than or equal to the first-level threshold and remains so for a preset time, a dry contact signal is output to the energy management system, which then controls the second circuit breaker to disconnect.

[0038] Furthermore, the control methods also include:

[0039] When the energy storage system is connected to the grid, when the energy storage converter is detected to be shut down and the first circuit breaker is closed, the control battery cluster supplies power to the control load through the DC-DC module.

[0040] When a battery cluster failure is detected, the automatic transfer switch switches to the ACDC module, which, along with the backup battery, simultaneously powers the control load.

[0041] Furthermore, the control methods also include:

[0042] Check if the battery clusters have returned to normal;

[0043] When the battery cluster returns to normal, control the first and second circuit breakers to close;

[0044] The control battery cluster charges the backup battery via a DC-DC module, while simultaneously supplying power to the control load.

[0045] According to an embodiment of the present invention, after the energy storage system is off-grid operated, the battery cluster can be directly connected to the high-voltage DC bus through the first circuit breaker, and a DC-DC module is connected in parallel on the high-voltage DC bus. The output terminal of the DC-DC module is connected to the control load such as the energy management system through the second circuit breaker. When the first circuit breaker and the second circuit breaker are closed, the battery cluster can directly supply power to the low-voltage DC bus through the DC-DC module, thereby directly supplying power to the control load such as the energy management system. In this embodiment, the battery clusters in the energy storage system can directly supply power to the low-voltage DC bus via the DC-DC module, and the control loads are all located on the low-voltage DC bus. Therefore, the power required by the control loads can be provided by the battery clusters without the need for AC-DC conversion through the PCS side. Unlike the electrical architecture of conventional energy storage systems where the control loads such as the energy management system are AC powered by the PCS side, the control loads in this embodiment are all DC powered, and there are no loads on the AC side. When there are no loads on the AC side of the energy storage system, high-power consumption devices such as the PCS are in standby mode with extremely low power consumption. Instead, low-power, low-consumption DC-DC modules supply power to the control loads such as the energy management system, achieving ultra-low power consumption. Attached Figure Description

[0046] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0047] Figure 1 This is an electrical architecture diagram of a battery cluster DC power distribution and energy storage system according to an embodiment of the present invention;

[0048] Figure 2 This is a communication architecture diagram of a battery cluster DC power distribution and energy storage system according to an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of the fire protection system of the battery cluster DC power distribution energy storage system according to an embodiment of the present invention;

[0050] Figure 4 This is a flowchart of the control method for a battery cluster DC power distribution and energy storage system according to an embodiment of the present invention.

[0051] The above figures include the following reference numerals:

[0052] 1. Battery pack; 2. First circuit breaker; 3. High-voltage DC bus; 4. DC-DC module; 5. Low-voltage DC bus; 6. Second circuit breaker; 7. Energy storage converter; 8. Backup battery; 9. AC-DC module; 10. Automatic transfer switch; 11. Undervoltage protector; 12. Energy management system; 13. Contactor; 14. Fire protection system; 15. Water pump; 16. Water tank; 17. Battery management system; 18. I / O module; 19. Indicator light; 20. Dehumidifier; 21. Water immersion sensor; 22. Display screen; 23. Temperature and humidity sensor; 24. Fan; 25. Communication module; 26. Liquid cooling controller; 27. Battery pack; 28. Electrically controlled valve; 29. ​​Liquid cooling compressor; 30. Fire protection piping; 31. Cooling piping. Detailed Implementation

[0053] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0054] See also Figures 1 to 3 As shown, according to an embodiment of the present invention, the battery cluster DC power distribution and energy storage system includes: a battery cluster 1, connected in parallel to a high-voltage DC bus 3 via a first circuit breaker 2; a DC-DC module 4, connected in parallel to the high-voltage DC bus 3, with a low-voltage DC bus 5 constructed at the end of the DC-DC module 4 away from the high-voltage DC bus 3, and a second circuit breaker 6 provided at the end of the low-voltage DC bus 5 connected to the DC-DC module 4; a control load, connected to the low-voltage DC bus 5, and located at the end of the second circuit breaker 6 away from the DC-DC module 4; and an energy storage converter 7, connected in parallel to the high-voltage DC bus 3.

[0055] Battery cluster 1, as the core component of the energy storage system, is connected to the high-voltage DC bus 3 via the first circuit breaker 2. This allows for charging during off-peak electricity price periods and discharging during peak electricity price periods, profiting from the peak-valley price difference and thus achieving the goal of peak shaving and valley filling for the large power grid, smoothing grid fluctuations, and improving grid stability. The DC-DC converter 4 converts the high-voltage DC to low-voltage DC, thereby converting the high-voltage DC from battery cluster 1 to low-voltage DC, providing a stable power supply for the control load. The DC-DC converter 4 uses a converter to transform the high-voltage DC from battery cluster 1 into low-voltage DC suitable for the control load, ensuring stable system operation in off-grid conditions.

[0056] The battery cluster DC power distribution energy storage system connects battery cluster 1 to the high-voltage DC bus 3 via the first circuit breaker 2. The high-voltage DC power is then converted to low-voltage DC power by the DC-DC module 4, forming the low-voltage DC bus 5. This provides stable power to the control load. Even when the energy storage converter 7 is shut down, the system can switch back to battery cluster 1 power supply mode via the first circuit breaker 2 and the second circuit breaker 6, ensuring the continuous operation of key control components. This effectively improves the system's reliability and safety, especially in off-grid operation and sudden failures. It ensures the effective execution of important functions such as fire protection and monitoring under abnormal system conditions. Furthermore, by optimizing the power distribution architecture, the system achieves ultra-low power consumption and full-power output capability, enhancing the economic benefits and practicality of the energy storage equipment.

[0057] In this embodiment, after the energy storage system is off-grid operated, the battery cluster 1 can be directly connected to the high-voltage DC bus 3 through the first circuit breaker 2, and a DC-DC module 4 is connected in parallel on the high-voltage DC bus. The output terminal of the DC-DC module 4 is connected to the control load such as the energy management system 12 through the second circuit breaker 6. When the first circuit breaker 2 and the second circuit breaker 6 are closed, the battery cluster 1 can directly supply power to the low-voltage DC bus 5 through the DC-DC module 4, thereby directly supplying power to the control load such as the energy management system 12. Since the battery cluster 1 in the energy storage system of this embodiment can be directly powered to the low-voltage DC bus 5 through the DC-DC module 4, and the control loads are all located on the low-voltage DC bus, the power required by the control loads can be provided by the battery cluster 1 without the need for AC-DC conversion through the PCS side. Unlike the electrical architecture of conventional energy storage systems where the control loads such as the energy management system 12 are powered by AC from the PCS side, the control loads in this embodiment are all powered by DC, and there are no loads on the AC side. When there are no loads on the AC side of the energy storage system, high-power power-consuming devices such as the PCS are in standby mode with extremely low power consumption. Instead, the low-power, low-consumption DC-DC module 4 powers the control loads such as the energy management system 12, which can achieve ultra-low power consumption.

[0058] When the PCS shuts down due to a system failure, battery cluster 1 can form a circuit with the DC-DC module 4 through the high-voltage DC bus 3. Therefore, battery cluster 1 can still supply power to the low-voltage DC bus directly through the DC-DC module 4. The shutdown of the PCS will not prevent battery cluster 1 from being unable to supply power to the control load. At the same time, since the device supplying power to the control load is battery cluster 1, it can provide more power. This not only avoids the embarrassing situation of battery cluster 1 being unable to be used due to PCS shutdown and improves the utilization efficiency of battery cluster 1, but also provides a longer standby time, which is hundreds of times longer than that of conventional UPS.

[0059] When battery cluster 1 is supplying power to the PCS normally, since the control load is directly connected to battery cluster 1 through low-voltage DC bus 5 and DC-DC module 4, it can be directly powered by battery cluster 1. There is no control load on the AC side, which can realize the full power output of the PCS and maximize the output capacity of the PCS.

[0060] Furthermore, energy storage systems contain numerous auxiliary devices. Conventional energy storage systems using AC power supply typically employ 220V AC power lines. Leakage or other issues can directly endanger lives. This embodiment utilizes a DC-DC module 4 to convert the high-voltage DC power from battery cluster 1 into low-voltage DC power to supply the control load. Compared to existing solutions that use 220V AC power for the control load, this reduces the voltage of the control load to a safe range, such as 24V, effectively preventing high-voltage safety issues during control load operation.

[0061] In one embodiment, the output voltage of the DC-DC module is 24V-30V.

[0062] In one embodiment, a backup battery 8 is also provided between the DC-DC module 4 and the second circuit breaker 6. The backup battery 8 is connected to the low-voltage DC bus 5 and is connected in parallel with the DC-DC module 4.

[0063] In the battery cluster DC power distribution and energy storage system, the backup battery 8 connected in parallel between the DC-DC module 4 and the second circuit breaker 6 is connected to the low-voltage DC bus 5, forming a dual power supply guarantee mechanism. When the main power supply, i.e., the battery cluster 1, fails and causes an output interruption, the backup battery 8 immediately takes over the power supply task, ensuring that key control loads such as the energy management system 12 and the fire protection system 14 continue to receive power support. This greatly enhances the stability and safety of the system in the event of abnormal situations or when operating off-grid, and achieves long-term standby capability and immediate emergency response.

[0064] In addition, since the backup battery 8 is located at the output end of the DC-DC module 4, the backup battery 8 can be charged through the high-voltage DC bus 3 and the DC-DC module 4 during the grid-connected operation of the energy storage system, ensuring that the backup battery 8 has sufficient power. During the off-grid operation of the energy storage system, the battery cluster 1 can also supply power to the backup battery 8 and the control load at the same time, ensuring that the backup battery 8 has sufficient power.

[0065] When battery cluster 1 fails or its power is insufficient while the device is off-grid, backup battery 8 can continue to supply power to the control load, ensuring the continuity and stability of the power supply to the control load.

[0066] In one embodiment, the control terminal of the first circuit breaker 2 is connected to the control load.

[0067] In the off-grid single-battery cluster DC power distribution energy storage system, the control terminal of the first circuit breaker 2 is directly connected to the control load, enabling the system to achieve real-time monitoring and intelligent control. When an abnormality is detected in the battery cluster 1 on the high-voltage DC bus 3, such as overload, short circuit, or thermal runaway, the energy management system 12 can respond quickly. By controlling the disconnection action of the first circuit breaker 2, the battery cluster 1 is immediately isolated from the high-voltage DC bus 3 to prevent the fault from spreading further and protect the system safety. At the same time, the power supply to the low-voltage DC bus 5 is maintained through the second circuit breaker 6, ensuring that the core control loads such as the energy management system 12, BMS, and fire protection system can still operate normally. This greatly improves the system's survivability under extreme conditions and its flexibility in responding to emergencies, effectively ensuring the overall stability and long-term operational safety of the energy storage system.

[0068] Since the control terminal of the first circuit breaker 2 is connected to the control load, the control of the first circuit breaker 2 is realized by the control load, which is powered by the battery cluster 1 or the backup battery 8. Therefore, even when operating off-grid, the control load can still control the first circuit breaker 2. In particular, when the battery cluster 1 fails, the backup battery 8 can supply power to the control load, so that the control load controls the first circuit breaker 2 to disconnect, thus preventing the battery cluster 1 from affecting the normal operation of the high-voltage DC bus.

[0069] In one embodiment, the battery cluster DC power distribution energy storage system further includes an ACDC module 9 and an automatic transfer switch 10. The automatic transfer switch 10 is connected to the output terminal of the DCDC module 4. The DCDC module 4 is connected to the main power supply of the automatic transfer switch 10. The ACDC module 9 is connected between the auxiliary power supply of the automatic transfer switch 10 and the energy storage converter 7.

[0070] The battery cluster DC power distribution energy storage system integrates an AC-CDC module 9 and an automatic transfer switch 10, forming a flexible power switching mechanism at the output of the DC-CDC module 4. When the DC-CDC module 4 is working normally, it prioritizes providing stable power to the low-voltage DC bus 5 via the automatic transfer switch 10 to support the operation of the control load. When the DC-CDC module 4 loses power or the battery cluster 1 malfunctions, the automatic transfer switch 10 can quickly switch from main power to auxiliary power, allowing the AC-CDC module 9 to draw power from the AC power source or the grid to continue supplying power to the control load. Even when the energy storage converter 7 is shut down, the AC-CDC module can still ensure the normal operation and safety monitoring of the entire system. This intelligent power switching design greatly enhances the system's redundancy and ability to cope with emergencies, ensuring the stability and reliability of the off-grid energy storage system under various operating modes. At the same time, by optimizing power management, it achieves economic efficiency and high efficiency in system operation.

[0071] In one embodiment, the battery cluster DC power distribution energy storage system further includes an undervoltage protector 11, which is connected to the low-voltage DC bus 5 and is used to collect the voltage of the low-voltage DC bus 5 and upload undervoltage information when the collected voltage is lower than a set threshold.

[0072] In this embodiment, the undervoltage protector 11 monitors the voltage level of the low-voltage DC bus 5 and promptly feeds back undervoltage information to the energy management system 12 when the voltage drops below a preset threshold. This can prevent the risk of performance degradation or shutdown of the control load due to insufficient voltage. Through early warning and automatic adjustment, the system can intelligently adjust the power supply strategy, such as starting the ACDC module 9 as an alternative power source or controlling the contactor 13 to disconnect secondary loads, so as to retain sufficient power supply to core components, such as the energy management system 12 and the fire protection system, to ensure the safe operation and long-term stability of the system. Especially in off-grid applications, the role of the undervoltage protector is more critical. It helps to extend the effective power supply time of the system's backup battery 8, avoid system failure due to low voltage, and improve the adaptability and sustainability of the entire energy storage system under various working conditions.

[0073] In one embodiment, the control load includes a core load and a secondary load. The core load includes an energy management system 12, and a contactor 13 is provided on the low-voltage DC bus 5. The secondary load is electrically connected to the backup battery 8 through the contactor 13. When the backup battery 8 supplies power to the control load, the energy management system 12 controls the contactor 13 to open when the undervoltage protector 11 detects that the voltage of the low-voltage DC bus 5 has reached the secondary threshold, and controls the second circuit breaker 6 to open when the undervoltage protector 11 detects that the voltage of the low-voltage DC bus 5 has reached the primary threshold.

[0074] In this embodiment, by dividing the controlled load into core loads and secondary loads managed by the energy management system 12, and establishing an adjustable electrical connection between them using contactor 13, the system can automatically execute a two-stage energy-saving and protection strategy based on the real-time monitoring of the low-voltage DC bus 5 voltage by the undervoltage protector 11 in the backup battery 8 power supply mode. First, when the voltage reaches the secondary threshold, the energy management system 12 controls the contactor 13 to disconnect, quickly separating the secondary load, reducing the power consumption of the backup battery, and ensuring the continuous operation of core control components such as the energy management system 12 under low power conditions. Second, when the voltage drops further to the primary threshold, the system further executes an emergency protection procedure, with the energy management system 12 controlling the second circuit breaker 6 to disconnect, completely cutting off the connection between all loads and the backup battery, avoiding damage caused by deep battery discharge. This hierarchical protection mechanism effectively extends the standby time of the system in off-grid or fault conditions and the lifespan of the backup battery, significantly enhancing the system's safety and economy, especially in resource-limited remote or independent power supply environments, where its advantages are particularly obvious.

[0075] In one embodiment, the control load includes a fire protection system 14, which includes a water pump 15 and a water tank 16. The water tank 16 contains coolant, and the water pump 15 is used to pump the coolant in the water tank 16. The water pump 15 is connected to each battery pack in the battery cluster 1 through multiple liquid cooling pipes, and each liquid cooling pipe is equipped with an electronically controlled valve 28.

[0076] In this embodiment, the fire protection system 14 is cleverly designed to combine a water pump 15 and a water tank 16 containing coolant. When the system detects thermal runaway in the battery pack within the battery cluster 1, the energy management system 12 responds quickly by starting the water pump 15 to pump the coolant from the water tank 16 to the affected battery pack. The flow direction and flow rate of the coolant are precisely controlled by the electronically controlled valve in the liquid cooling pipeline, achieving immediate cooling and immersion fire protection for the thermally runaway battery pack. This not only effectively curbs the spread of the fire and protects the system safety, but also allows the fire protection system 14 to operate independently with the power support of the low-voltage DC bus 5 and the backup battery 8 when the battery cluster 1 is off-grid or the main power supply is interrupted. This greatly enhances the self-protection capability and emergency response efficiency of the energy storage system under extreme conditions, ensuring the safety of personnel and property, reducing the damage caused by the fire to the system, and improving the stability and market competitiveness of the entire energy storage facility.

[0077] In one embodiment, the energy storage system further includes a battery management system 17, an I / O module 18, an indicator light 19, a dehumidifier 20, a water immersion sensor 21, a display screen 22, a temperature and humidity sensor 23, a fan 24, a communication module 25, and a liquid cooling controller 26. The core loads include an undervoltage protector 11, an energy management system 12, a water pump 15, a battery management system 17, and an I / O module 18. The secondary loads include an indicator light 19, a dehumidifier 20, a water immersion sensor 21, a display screen 22, a temperature and humidity sensor 23, a fan 24, a communication module 25, and a liquid cooling controller 26. The core loads are the loads necessary for the normal operation of the energy storage system, while the secondary loads are the loads that play an auxiliary role in the operation of the energy storage system.

[0078] In one embodiment, the fire protection system 14 further includes a liquid-cooled compressor 29, a fire protection pipe 30, and a cooling pipe 31. The cooling pipe 31 enters the battery pack 27 and exits, with coolant flowing within the cooling pipe 31 without entering the battery pack 27. The cooling pipe 31 regulates the temperature of the battery pack 27, ensuring that the battery pack 27 operates within its high-efficiency operating range. The outlet of the fire protection pipe 30 is connected to the battery pack 27 to introduce coolant into the battery pack 27 for immersion fire protection, thereby improving the fire protection effect. Fire-fighting pipeline 30 and cooling pipeline 31 are both connected to liquid-cooling pipeline. Liquid-cooling controller 26 and water tank 16 are both installed on liquid-cooling pipeline. Liquid-cooling pipeline and cooling pipeline 31 form a circulating cooling pipeline. Fire-fighting pipeline 30 is equipped with an electric control valve 28. Electric control valve 28 is closed under normal operating conditions to prevent coolant from directly entering the battery pack 27. It is only opened when the internal temperature of the battery pack exceeds the set value or when a fire occurs, so that coolant can quickly enter the battery pack through fire-fighting pipeline 30 for fire fighting.

[0079] In one embodiment, the coolant in the cooling pipes is a 50% aqueous solution of ethylene glycol.

[0080] See also Figure 4 As shown, according to an embodiment of the present invention, the control method of the battery cluster DC power distribution energy storage system includes: detecting whether the energy storage system is operating off-grid; when the energy storage system is operating off-grid, detecting whether the energy storage system has a fault; when the energy storage system has a fault, determining whether the fault is a fault of battery cluster 1; when the fault is not a fault of battery cluster 1, controlling the first circuit breaker 2 and the second circuit breaker 6 to close, and controlling battery cluster 1 to supply power to the control load through DC-DC module 4.

[0081] The control method of the battery cluster DC power distribution energy storage system dynamically monitors the system's operating status, especially the fault detection and response mechanism in off-grid mode. When a system fault other than the battery cluster is detected, it can quickly activate the conversion efficiency of the DC-DC module 4 by closing the first circuit breaker 2 and the second circuit breaker 6. This ensures that even in the event of main power failure or system anomaly, the battery cluster 1 can continuously provide stable power to the control load, including key components such as the energy management system 12 and the fire protection system 14. This not only maintains the core functions of the system from fault interference, but also effectively avoids unnecessary energy waste through intelligent power distribution control, significantly increases the power supply duration, enhances the self-sufficiency and safety of the energy storage system in off-grid and fault modes, and strengthens the overall reliability and resilience of the system in response to emergencies.

[0082] In one embodiment, the control method further includes: when the fault is a fault in battery cluster 1, controlling the first circuit breaker 2 to open and controlling the second circuit breaker 6 to close; controlling the backup battery 8 to supply power to the control load through the low-voltage DC bus 5.

[0083] When a fault is detected in battery cluster 1, it indicates that the control load can no longer be powered by battery cluster 1. At this time, the faulty battery cluster 1 is isolated by disconnecting the first circuit breaker 2, and the second circuit breaker 6 is closed. The system quickly switches to a mode where the backup battery 8 supplies power to the energy management system 12, the fire protection system, and other critical control loads through the low-voltage DC bus 5. This immediate response mechanism not only effectively prevents the fault from spreading and protects other components of the system from damage, but also ensures that the core functions of the energy storage system can continue to operate even if the main energy source fails. This greatly enhances the system's safety and survivability in emergencies. It also provides maintenance personnel with sufficient time to diagnose and repair problems, reduces the downtime caused by the system failure, and improves overall operating efficiency and user satisfaction.

[0084] In one embodiment, the control method further includes: when the fault is a fault in battery cluster 1, determining the fault type; when the fault type is a fire alarm, the backup battery 8 continuously supplies power, and the energy management system 12 controls the fire protection system 14 to fire until the backup battery 8 is depleted; when the fault type is a fire thermal runaway, the energy management system 12 identifies the thermal runaway cell number and determines the battery pack location of the corresponding cell; the backup battery 8 continuously supplies power, and the energy management system 12 controls the fire protection system 14 to inject coolant into the battery pack 27 at the corresponding location to submerge the battery pack.

[0085] When battery cluster 1 malfunctions and is identified as a fire alarm or thermal runaway, the energy storage system's control method responds rapidly. It not only provides uninterrupted power support to the energy management system 12 and the fire suppression system 14 via the backup battery 8, ensuring continuous fire suppression operations until the backup battery is depleted, but also, in the event of thermal runaway, the energy management system 12 accurately identifies and locates the faulty cell, thereby controlling the fire suppression system 14 to selectively inject coolant into the affected battery pack 27, achieving immersion fire suppression, effectively controlling and extinguishing the fire source, and preventing the accident from escalating. This series of intelligent fault handling procedures not only significantly enhances the system's safety protection capabilities but also minimizes the impact of faults on the overall system operation, ensuring the stability and long-term reliability of the energy storage system in off-grid conditions.

[0086] In one embodiment, the control method further includes: detecting the voltage of the backup battery 8; when the voltage of the backup battery 8 is greater than or equal to a secondary threshold, controlling the backup battery 8 to supply power to all control loads; when the voltage of the backup battery 8 is greater than a primary threshold and less than a secondary threshold, outputting a dry contact signal to the energy management system 12, the energy management system 12 controls the contactor 13 to open, the secondary loads are isolated from the backup battery 8, and the backup battery 8 only supplies power to the core load; when the voltage of the backup battery 8 is less than or equal to a primary threshold for a preset time, outputting a dry contact signal to the energy management system 12, the energy management system 12 controls the second circuit breaker 6 to open.

[0087] The battery cluster DC power distribution energy storage system uses undervoltage protector 11 to continuously monitor the voltage of backup battery 8 and intelligently adjusts the power supply mode according to the voltage level: when the backup battery voltage is not lower than the secondary threshold, it ensures that it supplies power to all control loads and maintains normal system operation; once the voltage drops to between the primary and secondary thresholds, the energy management system 12 automatically triggers the undervoltage protection mechanism, disconnects the secondary loads and backup battery by controlling contactor 13, and concentrates power resources to supply only the core loads such as energy management system 12 and fire protection system 14, so as to achieve continuous operation of key functions in low power mode; if the backup battery voltage drops further and remains below the primary threshold for a preset time, the energy management system takes the ultimate protection measure, controls the second circuit breaker 6 to disconnect, completely cuts off the backup battery from external power supply, and avoids over-discharge damage to battery health. This finely graded power management scheme significantly extends the standby time of the system in emergency situations and the life of backup batteries, ensures the stable operation of core control components, and effectively improves the overall safety and economic benefits of the energy storage system.

[0088] When the equipment triggers a low SOC or other faults in the battery cluster, the control equipment such as the energy management system 12 is powered and the system continues to operate. If the undervoltage protector 11 detects that the battery voltage is lower than the set threshold, and the backup battery 8 still has residual power, the undervoltage protector 11 will send a dry contact signal to the energy management system 12 through the input port of the I / O module 18. The energy management system 12 will then output a dry contact signal to the second circuit breaker 6 through the output port of the I / O module 18 and control the second circuit breaker 6 to open. All control equipment will lose power and wait for maintenance personnel to carry out subsequent processing.

[0089] When maintenance personnel arrive at the maintenance site and close the second circuit breaker 6 for the first time, the energy management system 12 does not operate and waits for a period of time. Maintenance personnel can perform data analysis and download operations by operating the energy management system 12. If the voltage of the low-voltage DC bus is still lower than the threshold and continues for a preset time, the energy management system 12 will output a dry contact signal to the second circuit breaker 6 through the output port of the I / O module again and control the second circuit breaker 6 to open, and all control equipment will lose power.

[0090] In one embodiment, the control method further includes: when the energy storage system is running in grid-connected mode, when the energy storage converter 7 is detected to be shut down and the first circuit breaker 2 is closed, the control battery cluster 1 supplies power to the control load through the DC-DC module 4; when a fault is detected in the battery cluster 1, the automatic transfer switch 10 switches to the AC-DC module 9, and the AC-DC module 9 and the backup battery 8 supply power to the control load simultaneously.

[0091] In grid-connected operation mode, when the energy storage system detects that the energy storage converter 7 is in a shutdown state, it keeps the first circuit breaker 2 closed, activating battery cluster 1 to supply power to the energy management system 12, fire protection, BMS, and other control loads via the DC-DC module 4, ensuring the continuity of critical functions even in the event of a converter failure. When battery cluster 1 itself fails, the system automatically triggers an intelligent switching scheme, with the automatic transfer switch 10 quickly switching to the AC-DC module 9, utilizing the grid to supply power to the low-voltage DC bus 5, which in turn supplies power to the control loads. While ensuring that the AC-DC module 9 is the primary power source, the backup battery 8 serves as an auxiliary power source. This dual-source power supply mechanism not only maximizes the stable operation of the energy storage system in emergencies, avoiding the risk of system paralysis due to a single energy source failure, but also significantly enhances the system's resilience and recovery capability in the face of sudden failures by integrating the synergistic effect of the backup battery and AC power. In actual control operations, the system can also directly supply power to the control loads via the grid while simultaneously charging the backup battery 8, ensuring the normal operation of the control loads.

[0092] In one embodiment, the control method further includes: detecting whether the battery cluster 1 has returned to normal; when the battery cluster 1 returns to normal, controlling the first circuit breaker 2 and the second circuit breaker 6 to close; controlling the battery cluster 1 to charge the backup battery 8 through the DC-DC module 4, and simultaneously supplying power to the control load.

[0093] In this embodiment, a real-time monitoring and intelligent recovery mechanism for the status of battery cluster 1 is incorporated. When battery cluster 1 is in a fault state, the backup battery 8 is used to supply power to the control load, while the status of battery cluster 1 is monitored. Once it is confirmed that battery cluster 1 has resumed normal operation, the first circuit breaker 2 and the second circuit breaker 6 can be closed to restore the circuit connection between battery cluster 1 and the control load. At this time, battery cluster 1 not only directly provides stable power to the energy management system 12, fire protection system and other control loads through the DC-DC module 4, but also charges the backup battery 8 to ensure the sufficient state of the backup power supply. This effectively realizes the smooth transition and optimized utilization between the main power supply and the backup power supply, significantly enhances the rapid recovery capability of the energy storage system after experiencing a fault, ensures the long-term stability and efficient operation of the system, and maintains the health level of the backup battery through continuous charging.

[0094] In one embodiment, the monitoring of battery cluster 1 and the closing of the first circuit breaker 2 and the second circuit breaker 6 can be automatically controlled by the energy storage system. The control load includes a battery cluster status monitoring module. When battery cluster 1 fails, the backup battery 8 supplies power to the control load and triggers the battery cluster status monitoring module to monitor the status of battery cluster 1. After the status of battery cluster 1 recovers, the battery cluster status monitoring module transmits a signal to the energy management system 12. The energy management system 12 controls the first circuit breaker 2 and the second circuit breaker 6 to close, and the energy storage system switches to the mode where battery cluster 1 supplies power. The backup battery 8 can then enter the charging state.

[0095] In one embodiment, monitoring of battery cluster 1 can be achieved through an energy storage system. The closing of the first circuit breaker 2 and the second circuit breaker 6 can be manually controlled. When the backup battery 8 supplies power to the control load, it triggers the battery cluster status monitoring module to work and monitor the status of battery cluster 1. After the status of battery cluster 1 is restored, the battery cluster status monitoring module sends an alert signal to inform the operator that the status of battery cluster 1 has been restored. At this time, the operator can control the first circuit breaker 2 and the second circuit breaker 6 to close, and the energy storage system switches to the mode where battery cluster 1 supplies power, and the backup battery 8 can enter the charging state.

[0096] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0097] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0098] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A battery cluster DC power distribution and energy storage system, characterized in that, include: The battery cluster (1) is connected to the high-voltage DC bus (3) via the first circuit breaker (2); A DC-DC module (4) is connected in parallel to the high-voltage DC bus (3). A low-voltage DC bus (5) is constructed at the end of the DC-DC module (4) away from the high-voltage DC bus (3). A second circuit breaker (6) is provided at the end of the low-voltage DC bus (5) connected to the DC-DC module (4). The control load is connected to the low-voltage DC bus (5) and located at the end of the second circuit breaker (6) away from the DC-DC module (4); The energy storage converter (7) is connected to the high-voltage DC bus (3).

2. The battery cluster DC power distribution and energy storage system according to claim 1, characterized in that, A backup battery (8) is also provided between the DC-DC module (4) and the second circuit breaker (6). The backup battery (8) is connected to the low-voltage DC bus (5) and is connected in parallel with the DC-DC module (4).

3. The battery cluster DC power distribution and energy storage system according to claim 1, characterized in that, The control terminal of the first circuit breaker (2) is connected to the control load.

4. The battery cluster DC power distribution and energy storage system according to claim 2, characterized in that, The battery cluster DC power distribution energy storage system also includes an ACDC module (9) and an automatic transfer switch (10). The automatic transfer switch (10) is connected to the output terminal of the DCDC module (4). The DCDC module (4) is connected to the main power of the automatic transfer switch (10). The ACDC module (9) is connected between the auxiliary power of the automatic transfer switch (10) and the energy storage converter (7).

5. The battery cluster DC power distribution and energy storage system according to claim 4, characterized in that, The battery cluster DC power distribution energy storage system also includes an undervoltage protector (11), which is connected to the low-voltage DC bus (5) and is used to collect the voltage of the low-voltage DC bus (5) and upload undervoltage information when the collected voltage is lower than a set threshold.

6. The battery cluster DC power distribution and energy storage system according to claim 5, characterized in that, The control load includes a core load and a secondary load. The core load includes an energy management system (12). A contactor (13) is provided on the low-voltage DC bus (5). The secondary load is electrically connected to the backup battery (8) through the contactor (13). When the backup battery (8) supplies power to the control load, the energy management system (12) controls the contactor (13) to disconnect when the undervoltage protector (11) detects that the voltage of the low-voltage DC bus (5) reaches the secondary threshold. When the undervoltage protector (11) detects that the voltage of the low-voltage DC bus (5) reaches the primary threshold, it controls the second circuit breaker (6) to disconnect.

7. The battery cluster DC power distribution and energy storage system according to claim 1, characterized in that, The control load includes a fire protection system (14), which includes a water pump (15) and a water tank (16). The water tank (16) contains coolant, and the water pump (15) is used to pump the coolant in the water tank (16). The water pump (15) is connected to each battery pack in the battery cluster (1) through multiple liquid cooling pipes. Each of the liquid cooling pipes is equipped with an electrically controlled valve (28).

8. A control method for a battery cluster DC power distribution and energy storage system as described in any one of claims 1 to 7, characterized in that, include: Check whether the energy storage system is operating off-grid; When the energy storage system is off-grid, detect whether the energy storage system has malfunctioned. When a fault occurs in the energy storage system, determine whether the fault is a fault in the battery cluster (1); When the fault is not a fault of the battery cluster (1), the first circuit breaker (2) and the second circuit breaker (6) are closed, and the battery cluster (1) supplies power to the control load through the DC-DC module (4).

9. The control method for the battery cluster DC power distribution energy storage system according to claim 8, characterized in that, Control methods also include: When the fault is a fault in the battery cluster (1), the first circuit breaker (2) is opened and the second circuit breaker (6) is closed; the backup battery (8) is supplied to the control load through the low-voltage DC bus (5).

10. The control method for the battery cluster DC power distribution and energy storage system according to claim 9, characterized in that, Control methods also include: When the fault is a battery cluster (1) fault, determine the fault type; When the fault type is fire alarm, the backup battery (8) continues to supply power, and the energy management system (12) controls the fire protection system (14) to spray until the backup battery (8) is depleted. When the fault type is fire thermal runaway, the energy management system (12) identifies the thermal runaway cell number and determines the battery pack location of the corresponding cell; Powered continuously by the backup battery (8), the energy management system (12) controls the fire suppression system (14) to inject coolant into the battery pack (27) at the corresponding location, submerging the battery pack.

11. The control method for the battery cluster DC power distribution and energy storage system according to claim 9, characterized in that, Control methods also include: Detect the voltage of the backup battery (8); When the voltage of the backup battery (8) is greater than or equal to the secondary threshold, the backup battery (8) is controlled to supply power to all control loads; When the voltage of the backup battery (8) is greater than the first threshold and less than the second threshold, a dry contact signal is output to the energy management system (12). The energy management system (12) controls the contactor (13) to disconnect, and the secondary load is isolated from the backup battery (8). The backup battery (8) only supplies power to the core load. When the voltage of the backup battery (8) is less than or equal to the first-level threshold and continues for a preset time, a dry contact signal is output to the energy management system (12), and the energy management system (12) controls the second circuit breaker (6) to disconnect.

12. The control method for the battery cluster DC power distribution and energy storage system according to claim 8, characterized in that, Control methods also include: When the energy storage system is connected to the grid, when the energy storage converter (7) is detected to be shut down and the first circuit breaker (2) is closed, the control battery cluster (1) supplies power to the control load through the DC-DC module (4); When a fault is detected in the battery cluster (1), the automatic transfer switch (10) switches to the ACDC module (9), and the ACDC module (9) and the backup battery (8) simultaneously supply power to the control load.

13. The control method for a battery cluster DC power distribution and energy storage system according to any one of claims 9 to 11, characterized in that, Control methods also include: Check whether the battery cluster (1) has returned to normal; When the battery cluster (1) returns to normal, control the first circuit breaker (2) and the second circuit breaker (6) to close; The control battery cluster (1) charges the backup battery (8) via the DC-DC module (4) and simultaneously supplies power to the control load.

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