All-vanadium redox flow battery energy recovery system for industry and commerce

Abstract

The invention relates to the technical field of energy storage, in particular to an industrial and commercial all-vanadium redox flow battery energy recovery system which comprises an electric pile of an all-vanadium redox flow battery, the electric pile is connected with a PSC energy storage converter through a direct-current bus set, the direct-current bus set is electrically connected with one input end of a DC / DC converter, and one output end of the DC / DC converter is electrically connected with a storage battery pack. And the DC / DC converter is used for charging the storage battery pack, and when the PSC energy storage converter and a pump circulation system of the all-vanadium redox flow battery system are in a shutdown state, residual electric energy in the electric pile is stored in the storage battery pack, so that an energy recovery mode of residual energy is realized. And residual electric energy in the electric pile can be stored in the storage battery pack, so that residual energy recovery is realized, and the problem that extra cost needs to be input to build a redundant power supply system is solved.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to an all-vanadium redox flow battery energy recovery system for industrial and commercial applications. Background Technology

[0002] In industrial and commercial applications, vanadium redox flow battery systems serve as large-scale energy storage devices. However, at the end of the charge / discharge cycle, some residual energy remains in the stack. This energy is dispersed and has unstable voltage, making it ineffective in traditional solutions. This not only wastes energy but also triggers self-discharge of the stack, leading to long-term system capacity degradation. Meanwhile, key auxiliary equipment such as the BMS (Battery Management System), main controller, data acquisition unit, and communication module are the core "brain" ensuring the safe and stable operation of the flow battery system; their power supply reliability directly determines the overall system safety.

[0003] In existing technologies, the power supply methods for auxiliary equipment have two main drawbacks: First, they rely on external UPS (Uninterruptible Power Supply), requiring additional investment to build a redundant power supply system, and external UPS is prone to failure, making it impossible to fully guarantee power continuity; second, they draw power directly from the main flow battery system, and when the main system stops, goes into standby mode, or experiences a grid failure, the auxiliary equipment will lose power along with the main system, resulting in the inability to monitor the electrolyte status, tank safety, and environmental parameters in real time, leading to the loss of critical operating data, and the need to rely on external power to restart the system after a failure, resulting in insufficient autonomy and reliability.

[0004] Furthermore, traditional solutions do not integrate residual energy recovery with auxiliary equipment power supply, resulting in both energy waste and power supply reliability issues, making it difficult to meet the core requirements of industrial and commercial scenarios for energy storage systems to be efficient, safe, and autonomous. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an energy recovery system for industrial and commercial vanadium redox flow batteries, which addresses the above-mentioned technical deficiencies. This system uses a DC / DC converter to electrically connect the DC bus group and the battery group, and can store the residual electrical energy in the battery stack into the battery group, thereby realizing the recovery of residual energy and solving the problem of needing to invest additional costs to build a redundant power supply system.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a vanadium redox flow battery energy recovery system for industrial and commercial use, including a vanadium redox flow battery stack, the stack being connected to a PSC energy storage converter via a DC bus group, the DC bus group being electrically connected to one input end of a DC / DC converter, and the output end of the DC / DC converter being electrically connected to a battery pack. The DC / DC converter is used to charge the battery pack. When the pump circulation system of the PSC energy storage converter and the all-vanadium redox flow battery system is shut down, the residual electrical energy in the stack is stored in the battery pack, realizing the energy recovery mode of residual energy.

[0007] This technical solution is further optimized by connecting the battery pack to the BMS battery management system via a DC / AC converter. During normal operation of the vanadium redox flow battery, the battery pack supplies power to the BMS battery management system via the DC / AC converter. The vanadium redox flow battery system can also supply power to the BMS battery management system during shutdown or standby periods, reducing the interference of main system power fluctuations on the operation of the BMS battery management system and enabling it to enter the uninterrupted power supply mode for critical loads.

[0008] To further optimize this technical solution, the battery pack is also electrically connected to the pump circulation system in the vanadium redox flow battery via a DC / AC converter. When the battery pack supplies power to both the BMS battery management system and the pump circulation system simultaneously via the DC / AC converter, the vanadium redox flow battery system can be directly black-started to restart the system after a crash.

[0009] To further optimize this technical solution, the battery pack is a lithium iron phosphate battery, and the capacity C of the battery pack satisfies: C = (auxiliary load static power consumption P1 × longest standby time T1 + black start peak power P2 × start-up time T2) × 1.2, where P1 is the total static power consumption of the auxiliary load cluster, T1 is designed according to the longest downtime cycle in industrial and commercial applications, P2 is the start-up peak power of the pump circulation system, and T2 ≤ 30 minutes.

[0010] This technical solution has been further optimized. The battery pack has a built-in SOC dynamic management module. When the system is connected to the grid, the SOC is maintained at 80%-95%; when the system is stopped and in standby mode, the SOC is allowed to drop to a minimum of 20%; and the SOC is ≥30% before black start.

[0011] To further optimize this technical solution, the energy recovery mode is triggered when the stack voltage reaches a preset threshold of 20V, and stopped when the residual stack voltage is below 10V or the battery pack SOC reaches 100%.

[0012] Compared with existing technologies, this invention has the following advantages: 1. The core of this solution lies in its ability to recover residual energy from the battery stack, reduce self-discharge, stabilize system capacity, and provide an independent and reliable uninterrupted backup power supply for key auxiliary equipment such as the BMS battery management system, using a relatively small investment (battery + DC / DC converter); 2. In energy recovery mode, residual energy is stored in the battery, and the battery stack returns to a stable state; 3. In critical load power supply mode, during system shutdown / standby, the main flow battery system is completely shut down, but the battery pack independently powers the BMS battery management system, data acquisition unit, and... Powered by the communication module, it can monitor electrolyte temperature, electrolyte tank status, and environmental safety 24 / 7, providing protection even when the main system is not in operation. The BMS battery management system continues to monitor and can issue early warnings or activate the heating system if abnormalities are detected (such as low temperature). System data is not lost, and clock and critical operating data records are maintained. 4. The all-vanadium redox flow battery system can be directly black-started, starting itself without any external power supply, which greatly improves the autonomy and reliability of the system. 5. Simplified external power supply design: There is no need to design complex redundant external UPS power supplies for the BMS and control system. Attached Figure Description

[0013] Figure 1 This is a block diagram illustrating the energy flow principle of an all-vanadium redox flow battery energy recovery system for industrial and commercial applications. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0015] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. Terms such as “up,” “down,” “left,” and “right” are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0016] Combination Figure 1As shown, a vanadium redox flow battery energy recovery system for industrial and commercial applications includes a vanadium redox flow battery stack, a positive electrolyte tank, a negative electrolyte tank, and a pump circulation system. The operation of the vanadium redox flow battery system is controlled by a battery management system (BMS). The stack is connected to a power storage converter (PSC) via a DC bus, and the stack is electrically connected to the AC power grid via a power storage converter (PCS). The PCS incorporates a charging AC / DC converter and a discharging DC / AC converter, used for AC / DC conversion during the charging process and DC / AC conversion during the discharging process, respectively. During charging, the PSC charges the stack via the charging AC / DC converter; during discharging, the pump circulation system circulates the electrolyte from the positive and negative electrolyte tanks to the stack for discharge, and the electrical energy stored in the vanadium redox flow battery is released to the AC power grid for power supply via the discharging DC / AC converter in the PSC.

[0017] The DC bus is electrically connected to the input of a DC / DC converter, and the output of the DC / DC converter is electrically connected to a battery pack. In this embodiment, the battery pack is a lithium iron phosphate battery with a built-in SOC dynamic management module. The DC / DC converter is used to convert the voltage during the charging process of the battery pack. The battery pack can be charged by the PCS energy storage converter (i.e., AC grid power) or by the vanadium redox flow battery stack. The battery pack is electrically connected to the BMS battery management system via the DC / AC converter, and also electrically connected to the pump circulation system in the vanadium redox flow battery via the DC / AC converter. The battery pack provides AC power to the BMS battery management system and the pump circulation system through the DC / AC converter.

[0018] In use, combined with Figure 1 As shown, when the pump circulation system of the PSC energy storage converter and the vanadium redox flow battery system is shut down, the electrolyte remaining in the stack still stores a portion of electrical energy. This residual energy can be stored in the battery pack via a DC / DC converter, achieving residual energy recovery—this is the energy recovery mode, or operating mode one. The specific trigger condition can be set to the stack voltage reaching a preset threshold of 20V, and the stop condition is when the residual stack voltage drops below 10V or the battery pack's SOC reaches 100%. Operating mode one ensures that the residual energy in the stack is effectively recovered when the vanadium redox flow battery finishes charging or discharging.

[0019] During normal operation of the vanadium redox flow battery, the battery pack supplies power to the BMS (Battery Management System) via a DC / AC converter. The vanadium redox flow battery system can also supply power to the BMS during shutdown or standby, reducing the interference of main system power fluctuations on the BMS operation and achieving operating mode two. When the system is connected to the grid, the SOC (State of Charge) is maintained at 80%-95%, and during shutdown or standby, the SOC is allowed to drop to a minimum of 20%.

[0020] When a power grid failure or system complete shutdown due to a fault requires a restart, the battery pack, as the sole power source, first powers the Battery Management System (BMS). The BMS checks the system status; if normal, the controller in the BMS uses the battery pack's power to start the pump circulation system. The electrolyte begins circulating, the battery stack builds up voltage, and the main system is successfully "awakened." This achieves self-starting without any external power supply, greatly improving the system's autonomy and reliability. The battery pack simultaneously powers both the BMS and the pump circulation system via a DC / AC converter. The vanadium redox flow battery system can directly perform a black start, restarting the system after a shutdown and achieving operating mode three. A state of charge (SOC) of ≥30% is required before a black start.

[0021] In this embodiment, the capacity C of the battery pack satisfies: C = (static power consumption of auxiliary load P1 × longest standby time T1 + peak power of black start P2 × start-up time T2) × 1.2, where P1 is the total static power consumption of the auxiliary load cluster, T1 is designed according to the longest downtime cycle of industrial and commercial use, P2 is the peak power of the pump circulation system at start-up, and T2 ≤ 30 minutes.

[0022] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A vanadium redox flow battery energy recovery system for commercial and industrial applications, comprising an electrical stack of vanadium redox flow batteries, said electrical stack being connected through a DC busbar group with a PSC energy storage converter, characterized in that: The DC bus group is electrically connected to one input terminal of the DC / DC converter, and the output terminal of the DC / DC converter is electrically connected to a battery pack. The DC / DC converter is used to charge the battery pack. When the pump circulation system of the PSC energy storage converter and the vanadium redox flow battery system is in a shutdown state, the residual electrical energy in the stack is stored in the battery pack, realizing the energy recovery mode of residual energy.

2. A vanadium redox flow battery energy recovery system for commercial and industrial use according to claim 1, characterized in that: The battery pack is electrically connected to the BMS battery management system via a DC / AC converter. During normal operation of the vanadium redox flow battery, the battery pack supplies power to the BMS battery management system through the DC / AC converter. The vanadium redox flow battery system can also supply power to the BMS battery management system during shutdown or standby periods, reducing the interference of main system power fluctuations on the operation of the BMS battery management system and entering the uninterrupted power supply mode for critical loads.

3. A vanadium redox flow battery energy recovery system for commercial and industrial use according to claim 2, characterized in that: The battery pack is also electrically connected to the pump circulation system in the vanadium redox flow battery via a DC / AC converter. When the battery pack supplies power to both the BMS battery management system and the pump circulation system simultaneously via the DC / AC converter, the vanadium redox flow battery system can be directly black-started to restart the system after a crash.

4. The vanadium redox flow battery energy recovery system for industrial and commercial use according to claim 1, characterized in that: The battery pack is a lithium iron phosphate battery, and the capacity C of the battery pack satisfies: C = (auxiliary load static power consumption P1 × longest standby time T1 + black start peak power P2 × start-up time T2) × 1.2, where P1 is the total static power consumption of the auxiliary load cluster, T1 is designed according to the longest downtime cycle in industrial and commercial applications, P2 is the peak power of the pump circulation system at startup, and T2 ≤ 30 minutes.

5. The vanadium redox flow battery energy recovery system for industrial and commercial use according to claim 4, characterized in that: The battery pack has a built-in SOC dynamic management module. When the system is connected to the grid, the SOC is maintained at 80%-95%; when the system is stopped and in standby mode, the SOC is allowed to drop to a minimum of 20%; and the SOC is ≥30% before black start.

6. The vanadium redox flow battery energy recovery system for industrial and commercial use according to claim 5, characterized in that: The energy recovery mode is triggered when the stack voltage reaches a preset threshold of 20V, and stopped when the residual stack voltage is below 10V or the battery pack SOC reaches 100%.

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