A flow battery and methods and apparatus for controlling the same

Abstract

The application relates to the technical field of energy storage, and discloses a flow battery and a control method and device thereof. The flow battery comprises a multi-port DC-DC circuit, a first end of the multi-port DC-DC circuit is connected with a first DC bus, a second end of the multi-port DC-DC circuit is connected with a second DC bus, a third end of the multi-port DC-DC circuit is connected with an energy storage battery, and a fourth end of the multi-port DC-DC circuit is connected with a DC load; a voltage conversion circuit, a first end of the voltage conversion circuit is connected with an AC bus, a second end of the voltage conversion circuit is connected with the first DC bus, the second end of the voltage conversion circuit is connected with a third end thereof through an internal DC switch, the third end of the voltage conversion circuit is connected with the second DC bus, the third end of the voltage conversion circuit is connected with an electric pile, and the voltage conversion circuits are connected through a bus switch. Through a single multi-port DC-DC circuit, three core functions of zero starting voltage boosting, active balancing and black start of the flow battery are realized, and stable DC power supply can be provided for the DC load.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, specifically to a flow battery and its control method and apparatus. Background Technology

[0002] In new energy power systems, energy storage topology is the core carrier for realizing energy storage, conversion, and stable dispatch. The common DC bus architecture, due to its advantages of simple energy transmission paths and strong multi-port coordination, has become one of the mainstream topologies for flow battery energy storage systems. This type of topology needs to consider the diverse requirements of grid-side adaptation, multi-stack management on the energy storage side, and continuous power supply to the load side. Its core technical challenge lies in how to achieve efficient energy allocation among the flow battery stack, auxiliary energy storage units, and DC loads through topology configuration optimization, while simultaneously meeting the system's operational stability requirements under different operating conditions such as grid connection, off-grid operation, and fault switching.

[0003] In existing technologies, energy management in common DC bus energy storage topologies often employs single bus coupling or independent port control, making it difficult to achieve functional coordination between bus electrical isolation, multi-source energy directional dispatch, and active stack balancing. Conventional topologies compensate for functional shortcomings by adding independent balancing devices and black-start power supplies, which not only increases the system's hardware complexity and cost but also reduces system response speed and operational reliability due to cumbersome multi-device collaborative control logic. This makes them unsuitable for the higher requirements of flexible configuration, efficient operation and maintenance, and emergency response capabilities in new energy grid-connected scenarios. Summary of the Invention

[0004] This invention provides a flow battery and its control method and apparatus to solve the problem that energy management in common DC bus energy storage topologies often adopts a single bus coupling or independent port control method, which makes it difficult to achieve functional coordination between bus electrical isolation, multi-source energy directional scheduling and active stack balancing.

[0005] In a first aspect, the present invention provides a flow battery, comprising: a multi-port DC-DC circuit, at least one energy storage unit, each energy storage unit including a voltage conversion circuit and a stack, wherein a first terminal of the multi-port DC-DC circuit is connected to a first DC bus, a second terminal of the multi-port DC-DC circuit is connected to a second DC bus, a third terminal of the multi-port DC-DC circuit is connected to the energy storage battery, and a fourth terminal of the multi-port DC-DC circuit is connected to a DC load; a first terminal of the voltage conversion circuit is connected to an AC bus, a second terminal of the voltage conversion circuit is connected to the first DC bus, the second terminal of the voltage conversion circuit is connected to its third terminal through an internal DC switch, the third terminal of the voltage conversion circuit is connected to the second DC bus, the third terminal of the voltage conversion circuit is connected to a stack, and the voltage conversion circuits are connected to each other through a bus switch.

[0006] In one optional embodiment, the voltage conversion circuit further includes a step-up transformer and a rectifier circuit, wherein the low-voltage side of the step-up transformer is connected to the AC bus, and the high-voltage side of the step-up transformer is connected to the AC side of the rectifier circuit; the DC side of the rectifier circuit is the second terminal of the voltage conversion circuit.

[0007] In one optional embodiment, the multi-port DC-DC circuit includes: a multi-port DC-DC converter and a control switch, wherein a first terminal of the multi-port DC-DC converter is connected to a first DC bus via the control switch, a second terminal of the multi-port DC-DC converter is connected to a second DC bus, a third terminal of the multi-port DC-DC converter is connected to an energy storage battery, and a fourth terminal of the multi-port DC-DC converter is connected to a DC load.

[0008] Secondly, the present invention provides a control method for a flow battery. Based on the above-mentioned flow battery, the method includes: controlling the on / off states of a bus switch, a DC switch, and a control switch based on the voltage state of a first DC bus and a second DC bus, the state of charge of the energy storage battery, and the power demand of the DC load, so as to reconstruct the electrical connection relationship between the first DC bus and the second DC bus; controlling the operating mode of a multi-port DC-DC converter to realize the directional flow and transformation of energy between the grid side, the flow battery side, the energy storage battery side, and the load side; monitoring the operating parameters of each battery stack, and selectively engaging or disengaging the target flow battery stack through the DC switch to maintain the stable operation of the second DC bus.

[0009] In one optional implementation, when the flow battery is started for the first time, all DC switches are disconnected and all bus switches are closed, and the multi-port DC-DC converter is controlled to charge the DC load; when the flow battery is started with low-current activation charging, all DC switches are disconnected and a preset number of bus switches are closed.

[0010] In one alternative implementation, when the flow battery is operating normally, the method includes: disconnecting the bus switch and the control switch; and closing the DC switch.

[0011] In one alternative implementation, when a single energy storage unit or a single voltage conversion circuit fails, the method includes switching the bus switch to disconnect the single faulty device and connect the non-faulty device to other energy storage units to continue operation.

[0012] In one alternative implementation, when the stack voltage is inconsistent, the process of maintaining stable operation of the second DC bus includes controlling the multi-port DC-DC converter to charge the stack voltage to a preset voltage threshold.

[0013] In one alternative implementation, when the AC system is powered off or a black start is required in an emergency, the method includes: disconnecting the control switch and closing a preset number of bus switches; controlling the energy storage battery to supply power to the DC load through a multi-port DC-DC converter, while simultaneously charging a preset number of fuel cells.

[0014] Thirdly, the present invention provides a control device for a flow battery, comprising: a first control module, used to control the on / off states of a bus switch, a DC switch, and a control switch based on the voltage state of a first DC bus and a second DC bus, the state of charge of the energy storage battery, and the power demand of the DC load, so as to reconstruct the electrical connection relationship between the first DC bus and the second DC bus, control the operating mode of the multi-port DC-DC converter, and realize the directional flow and transformation of energy between the grid side, the flow battery side, the energy storage battery side, and the load side; and a second control module, used to monitor the operating parameters of each flow battery stack, and selectively engage or disengage the target flow battery stack through a DC switch group to maintain the stable operation of the second DC bus.

[0015] Fourthly, the present invention provides an electronic device, comprising: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to perform the control method of the flow battery of the second aspect above or any corresponding embodiment thereof.

[0016] Fifthly, the present invention provides a computer-readable storage medium storing computer instructions for causing a computer to execute the control method for a flow battery according to the second aspect or any corresponding embodiment thereof.

[0017] In a sixth aspect, the present invention provides a computer program product, including computer instructions for causing a computer to execute the control method for a flow battery according to the second aspect or any corresponding embodiment thereof.

[0018] Beneficial effects:

[0019] This invention presents an integrated design scheme for a flow battery with a common DC bus. Through a single multi-port DC-DC converter, the three core functions of the flow battery—zero-start boost, active balancing, and black start—are realized in one stop. At the same time, it can provide stable DC power supply for the flow battery's control system, control board, circulating pump, and other equipment.

[0020] The common DC bus integrated architecture designed in this invention can significantly reduce the number of DC / DC converters required for zero-start-up of flow batteries, effectively reducing the initial investment cost of flow battery energy storage systems, while reducing energy loss during system operation and improving overall operating efficiency.

[0021] When the system encounters a fault condition, the present invention can accurately disconnect the faulty unit by flexibly switching the DC bus switch, and reconnect the non-faulty equipment to other energy storage units for continuous operation, effectively improving the operational reliability and charge / discharge capacity utilization of the flow battery energy storage system, and reducing various operational losses caused by the system fault.

[0022] This invention relies on a multi-port DC-DC converter to achieve active equalization control of flow batteries. This control method has high conversion efficiency and requires fewer components, which not only effectively controls the system hardware cost but also significantly improves the operational reliability of the equalization function. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of a flow battery according to an embodiment of the present invention; Figure 2 This is a schematic flowchart of a first method for controlling a flow battery according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the zero-start voltage boost principle of a flow battery according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the normal operation principle of a flow battery according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the power supply principle of a flow battery according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] It is understood that before using the technical solutions disclosed in the various embodiments of the present invention, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in the present invention and their authorization should be obtained in accordance with relevant laws and regulations through appropriate means.

[0027] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] This embodiment provides a flow battery, including: Figure 1 As shown, a multi-port DC-DC circuit 1 and at least one energy storage unit 2 are included, each energy storage unit including a voltage conversion circuit 21 and an energy stack 22.

[0029] like Figure 1 As shown, the first terminal of the multi-port DC-DC circuit 1 is connected to the first DC bus 3, the second terminal of the multi-port DC-DC circuit 1 is connected to the second DC bus 4, the third terminal of the multi-port DC-DC circuit 1 is connected to the energy storage battery 5, and the fourth terminal of the multi-port DC-DC circuit 1 is connected to the DC load 6; the first terminal of the voltage conversion circuit 21 is connected to the AC bus 7, the second terminal of the voltage conversion circuit 21 is connected to the first DC bus, the second terminal of the voltage conversion circuit 21 is connected to its third terminal through its internal DC switch 211, the third terminal of the voltage conversion circuit 21 is connected to the second DC bus 4, the third terminal of the voltage conversion circuit 21 is connected to a stack 22, and the voltage conversion circuits 21 are connected to each other through a bus switch 8.

[0030] Specifically, the multi-port DC-DC circuit 1 is a multi-channel power conversion and energy-oriented regulation device. Based on the principle of multi-port power conversion, it can flexibly switch operating modes to adapt to different system operating requirements. It can output a small current to achieve the zero-start voltage boost function of constant current charging, and it can also perform compensatory charging according to the output voltage deviation of each stack 22. Through energy allocation, it can achieve active balancing between stacks 22. At the same time, the circuit can perform voltage conversion and power regulation of the energy storage battery 5 to provide a stable DC power supply for the DC load 6 of the flow battery. In the emergency situation of AC system power failure, it can also use the energy storage battery 5 as an energy source to complete the black start regulation of the system. Moreover, it can achieve efficient energy allocation between different DC buses during normal operation, effectively reducing the operating loss of the system.

[0031] Specifically, each energy storage unit 2 is an independent electrical energy conversion and electrochemical energy storage module. The voltage conversion circuit 21 is used for AC-DC conversion. The DC switch 211 integrated inside is based on the principle of electronic control switching, which can realize the independent switching control of a single energy storage unit 2 and the system bus, ensuring the independent operation capability of a single energy storage unit 2, and can also quickly cut off the power path of the faulty unit under fault conditions.

[0032] Specifically, the bus switch 8 serves as a collaborative control component among the energy storage units 2, enabling the networking and disconnection control of each energy storage unit 2. It can flexibly switch operating states according to the actual operating load of the system, grid conditions, and equipment fault status. When multiple energy storage units 2 are running in parallel, it ensures the overall operational coordination of the system and the stability of the bus voltage. When a single or partial energy storage unit 2 or PCS fails, it can quickly and accurately disconnect the faulty unit and renetwork the non-faulty units, allowing non-faulty equipment to connect to other energy storage units 2 for continuous operation. This effectively improves the system's charging and discharging capacity utilization and operational reliability, and reduces system energy loss caused by faults.

[0033] Optionally, the DC load 6 includes a control system for the flow battery, a control board, a circulating pump powered by DC, etc.

[0034] In one alternative implementation, such as Figure 1 As shown, the voltage conversion circuit 21 also includes a step-up transformer 212 and a rectifier circuit 213. The low-voltage side of the step-up transformer 212 is connected to the AC bus 7, and the high-voltage side of the step-up transformer 212 is connected to the AC side of the rectifier circuit 213. The DC side of the rectifier circuit 213 is the second terminal of the voltage conversion circuit 21.

[0035] In one alternative implementation, such as Figure 1 As shown, the multi-port DC-DC circuit 1 includes a multi-port DC-DC converter 11 and a control switch 12. The first terminal of the multi-port DC-DC converter 11 is connected to the first DC bus 3 through the control switch 12. The second terminal of the multi-port DC-DC converter 11 is connected to the second DC bus 4. The third terminal of the multi-port DC-DC converter 11 is connected to the energy storage battery 5. The fourth terminal of the multi-port DC-DC converter 11 is connected to the DC load 6.

[0036] Specifically, the multi-port DC-DC converter 11, as the core power conversion and energy dispatching unit of the circuit, can flexibly switch working modes according to the system operating conditions, realize voltage level conversion, power regulation and energy directional flow between different ports, and simultaneously meet the zero-start voltage boost requirement of small current constant current charging, the active equalization compensation requirement of voltage deviation of fuel cell stack 22, the energy supply requirement during black start, and the stable power supply requirement of DC load 6. By integrating multiple power conversion functions in a single device, the number of power conversion devices in the system is effectively reduced, and the initial investment of equipment and system operating losses are reduced.

[0037] Specifically, the control switch 12 relies on the working principle of power electronic control switching. As the core component for switching operating conditions and safety protection between the multi-port DC-DC converter 11 and the corresponding DC bus, it can perform precise switching actions according to the operating condition instructions of the energy storage management system. It works with the converter to achieve smooth switching between different operating modes of the system. At the same time, it can achieve rapid shutdown when the system fails, effectively blocking the energy conduction on the fault side and avoiding damage to the multi-port DC-DC converter 11 caused by the fault impact. This ensures the operational safety and service life of the converter and provides hardware-level switching control support for the fault tolerance and operating condition reconfiguration of the entire flow battery energy storage system.

[0038] This embodiment provides a control method for a flow battery, based on the above-described flow battery, such as... Figure 2 As shown, the method includes: Step S1: Based on the voltage state of the first DC bus and the second DC bus 4, the state of charge of the energy storage battery 5, and the power demand of the DC load 6, control the on / off state of the bus switch 8, DC switch 211, and control switch 12 to reconstruct the electrical connection between the first DC bus and the second DC bus 4, control the working mode of the multi-port DC-DC converter 11, and realize the directional flow and transformation of energy between the grid side, the flow battery side, the energy storage battery 5 side, and the load side.

[0039] Specifically, the orderly operation of each switch enables flexible reconfiguration of the electrical connection between the first DC bus and the second DC bus 4, adapting to the topology requirements under different operating conditions such as zero-start boost, normal charging and discharging, fault tolerance, and black start. At the same time, based on the actual energy flow requirements of the system, the operating mode of the multi-port DC-DC converter 11 is dynamically matched and adjusted, so that the converter's voltage conversion ratio, power transmission direction, output current characteristics, and other parameters are adapted to the current operating conditions, thereby achieving efficient energy conversion and degree of the converter, and ultimately achieving on-demand directional flow, conversion, and distribution of energy between the grid side, the flow battery side, the energy storage battery 5 side, and the load side.

[0040] Step S2: Monitor the operating parameters of each fuel cell stack 22, and selectively engage or disengage the target flow battery stack 22 via DC switch 211 to maintain the stable operation of the second DC bus 4.

[0041] Specifically, based on the monitored operating parameters of the fuel cell stack 22 and combined with the real-time operating requirements of the second DC bus 4, including key indicators such as bus voltage stability range, power input and output limits, and energy transmission efficiency, a comprehensive analysis and quantitative assessment is conducted on the current operating status, available energy storage capacity, operational reliability, and impact on the overall stability of the bus for each fuel cell stack 22. Target fuel cell stacks requiring adjustment of their switching status are identified, and the direction of control for activation or deactivation is clarified. Finally, based on the switching decision formed by the comprehensive assessment, the DC switch 211 of the corresponding fuel cell stack 22 is selectively controlled. The activation or deactivation of the target fuel cell stack is completed through the orderly switching action of the DC switch 211, allowing the operating status of the fuel cell stack cluster to dynamically match the real-time operating requirements of the second DC bus 4.

[0042] In one optional implementation, when the flow battery is started for the first time, all DC switches 211 are disconnected and all bus switches 8 are closed, and the multi-port DC-DC converter 11 is controlled to charge the DC load 6; when the flow battery is started with low-current activation charging, all DC switches 211 are disconnected and a preset number of bus switches 8 are closed.

[0043] Specifically, refer to Figure 3 During the initial startup phase of the flow battery, a small-current activation charging operation is required for the stack 22. At this time, all DC switches 211 are disconnected and the bus switch 8 is closed. The multi-port DC-DC converter 11 then provides a small-current charge to the flow battery stack 22. Simultaneously, this multi-port DC-DC converter 11 provides a stable power supply to the flow battery's control system, BMS board, circulating pump, and other equipment, ensuring the normal operation of auxiliary equipment during startup. During the small-current activation charging process, flexible operation of the DC bus switch allows for independent charging of a single stack 22, parallel charging of two stacks 22, or even simultaneous charging of up to N stacks 22, adapting to different on-site startup requirements.

[0044] In one alternative implementation, when the flow battery is operating normally, the method includes: disconnecting the bus switch 8 and the control switch 12; and closing the DC switch 211.

[0045] Specifically, refer to Figure 4 When the flow battery enters normal operating condition, all bus switches 8 on the first DC bus and the second DC bus 4 are closed, control switch 12 is closed, and all DC switches 211 are closed, thereby constructing an independent operating architecture for N energy storage battery units 5, realizing the autonomous and independent operation of each energy storage battery unit 5.

[0046] In an alternative implementation, when a single energy storage unit 22 or a single voltage conversion circuit 21 fails, the method includes switching the bus switch 8 to disconnect the single faulty device and connect the non-faulty device to other energy storage units 2 to continue operation.

[0047] Specifically, during the actual operation of the flow battery energy storage system, if a single stack 22 or a single PCS is detected to be faulty and unable to participate in the system's charging, discharging, and energy dispatching, the system's bus switch 8 can be switched on and off. This means disconnecting the bus switch 8 connected to the faulty device to quickly remove the faulty stack 22 or faulty PCS from the circuit topology of the entire energy storage system, thereby achieving electrical isolation between the faulty device and the rest of the normally operating parts of the system.

[0048] After the faulty equipment is accurately isolated, the flexible networking characteristics of the common DC bus are used to reconnect all non-faulty stacks 22, PCS and other equipment in the system to the remaining normal energy storage units 2, and quickly reconstruct a new stable operating topology. This allows these non-faulty devices to continue to participate in the charging, discharging, energy conversion and scheduling of the system normally, and will not be taken out of operation due to the failure of local equipment.

[0049] In one alternative implementation, when the voltage of the fuel cell stack 22 is inconsistent, the process of maintaining the stable operation of the second DC bus 4 includes controlling the multi-port DC-DC converter 11 to charge the voltage of the fuel cell stack 22 to a preset voltage threshold.

[0050] Specifically, when the voltages of the stacks 22 are inconsistent, based on the system's preset voltage balancing standard and combined with the actual terminal voltage detection data of each stack 22, a unified preset voltage threshold is determined. Then, the multi-port DC-DC converter 11 is controlled to switch to the active balancing charging mode, providing an appropriate compensation charging current for all stacks 22 with voltages lower than the preset threshold. Precise charging is performed according to the established balancing charging strategy until the voltages of these stacks 22 with low voltages are smoothly charged to the system's preset voltage threshold, so that the terminal voltages of each stack 22 are restored to a consistent balanced state. This eliminates the bus operation disturbance caused by the inconsistent voltages of the stacks 22 from the root, and achieves stable operation of the second DC bus 4.

[0051] In one alternative implementation, when the AC system is powered off or a black start is required in an emergency, the method includes: disconnecting the control switch 12 and closing a preset number of bus switches 8; controlling the energy storage battery 5 to supply power to the DC load 6 through the multi-port DC-DC converter 11, while simultaneously charging a preset number of fuel cells 22.

[0052] Specifically, the multi-port DC / DC converter is connected to the energy storage battery 5. Under normal system operation, the control switch 12 remains open, and the energy storage battery 5 is connected to the second DC bus 4 via the multi-port DC-DC converter 11, always in a hot standby state. When the AC system experiences a power outage or other emergency conditions requiring a black start operation, the energy storage battery 5 serves as the system's black start power source. At this time, one or more bus switches 8 on the second DC bus 4 are closed, providing a stable power supply to the DC load 6 through the multi-port DC-DC converter 11, while simultaneously charging one or more fuel cell stacks 22, thereby realizing the black start function of the entire flow battery energy storage system.

[0053] In one alternative implementation, the flow battery power supply schematic is as follows: Figure 5 As shown, the fuel cell stack 22 discharges to the multi-port DC-DC converter 11. The multi-port DC-DC converter 11 converts the DC power to a voltage and supplies power to the DC load 6, namely the BMS, PCS, communication power cabinet, and circulating pump.

[0054] This embodiment provides a control device for a flow battery, the device comprising: The first control module is used to control the on / off states of the bus switch 8, DC switch 211, and control switch 12 based on the voltage state of the first DC bus and the second DC bus 4, the state of charge of the energy storage battery 5, and the power demand of the DC load 6, so as to reconstruct the electrical connection relationship between the first DC bus and the second DC bus 4, control the working mode of the multi-port DC-DC converter 11, and realize the directional flow and transformation of energy between the grid side, the flow battery side, the energy storage battery 5 side, and the load side. The second control module is used to monitor the operating parameters of each flow battery stack and selectively engage or disengage the target flow battery stack through the DC switch 211 group to maintain the stable operation of the second DC bus 4.

[0055] The control device for a flow battery provided in this embodiment of the invention can execute the control method for a flow battery provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects for executing the method. Further functional descriptions of the various modules and units described above are the same as in the corresponding embodiments described above, and will not be repeated here.

[0056] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0057] The following is a detailed reference. Figure 6The diagram illustrates a structural schematic suitable for implementing an electronic device according to embodiments of the present invention. The electronic device may include a processor (e.g., a central processing unit, graphics processor, etc.) 001, which can perform various appropriate actions and processes according to a program stored in read-only memory (ROM) 002 or a program loaded from memory 008 into random access memory (RAM) 003. The RAM 003 also stores various programs and data required for the operation of the electronic device. The processor 001, ROM 002, and RAM 003 are interconnected via bus 004. An input / output (I / O) interface 005 is also connected to bus 004.

[0058] Typically, the following devices can be connected to I / O interface 005: input devices 006 including, for example, touchscreens, touchpads, keyboards, mice, cameras, microphones, accelerometers, gyroscopes, etc.; output devices 007 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; memory devices 008 including, for example, magnetic tapes, hard disks, etc.; and communication devices 009. Communication device 009 allows electronic devices to exchange data via wireless or wired communication with other devices. Although Figure 6 Electronic devices with various devices are shown, but it should be understood that it is not required to implement or have all of the devices shown, and more or fewer devices may be implemented or have instead.

[0059] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication device 009, or installed from memory 008, or installed from ROM 002. When the computer program is executed by processor 001, it performs the functions defined in the control method for a flow battery according to embodiments of the present invention.

[0060] Figure 6 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0061] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the control method for the flow battery shown in the above embodiments is implemented.

[0062] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0063] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A flow battery, characterized in that, include: A multi-port DC-DC circuit (1) and at least one energy storage unit (2), each energy storage unit (2) including a voltage conversion circuit (21) and an energy stack (22), wherein, The first end of the multi-port DC-DC circuit (1) is connected to the first DC bus (3), the second end of the multi-port DC-DC circuit (1) is connected to the second DC bus (4), the third end of the multi-port DC-DC circuit (1) is connected to the energy storage battery (5), and the fourth end of the multi-port DC-DC circuit (1) is connected to the DC load (6). The first end of the voltage conversion circuit (21) is connected to the AC bus (7), the second end of the voltage conversion circuit (21) is connected to the first DC bus, the second end of the voltage conversion circuit (21) is connected to its third end through its internal DC switch (211), the third end of the voltage conversion circuit (21) is connected to the second DC bus (4), the third end of the voltage conversion circuit (21) is connected to a fuel cell stack (22), and the voltage conversion circuits (21) are connected to each other through a bus switch (8).

2. The flow battery according to claim 1, characterized in that, The voltage conversion circuit (21) further includes: a step-up transformer (212) and a rectifier circuit (213), wherein, The low-voltage side of the step-up transformer (212) is connected to the AC bus (7), and the high-voltage side of the step-up transformer (212) is connected to the AC side of the rectifier circuit (213). The DC side of the rectifier circuit (213) is the second terminal of the voltage conversion circuit (21).

3. The flow battery according to claim 1, characterized in that, The multi-port DC-DC circuit (1) includes: a multi-port DC-DC converter (11) and a control switch (12), wherein, The first end of the multi-port DC-DC converter (11) is connected to the first DC bus (3) through the control switch (12), the second end of the multi-port DC-DC converter (11) is connected to the second DC bus (4), the third end of the multi-port DC-DC converter (11) is connected to the energy storage battery (5), and the fourth end of the multi-port DC-DC converter (11) is connected to the DC load (6).

4. A control method for a flow battery, characterized in that, Based on the flow battery according to any one of claims 1-3, the method comprises: Based on the voltage state of the first DC bus and the second DC bus (4), the state of charge of the energy storage battery (5) and the power demand of the DC load (6), the on / off states of the bus switch (8), the DC switch (211) and the control switch (12) are controlled to reconstruct the electrical connection between the first DC bus and the second DC bus (4), control the working mode of the multi-port DC-DC converter (11), and realize the directional flow and transformation of energy between the grid side, the flow battery side, the energy storage battery (5) side and the load side. The operating parameters of each battery stack (22) are monitored, and the target flow battery stack is selectively put into or taken out through the DC switch (211) to maintain the stable operation of the second DC bus (4).

5. The control method for a flow battery according to claim 4, characterized in that, The method includes: When the flow battery is started for the first time, all DC switches (211) are disconnected and all bus switches (8) are closed to control the multi-port DC-DC converter (11) to charge the DC load (6). When the flow battery is activated and charged with a small current, all DC switches (211) are disconnected and a preset number of bus switches (8) are closed.

6. The control method for a flow battery according to claim 4, characterized in that, When the flow battery is operating normally, the method includes: Disconnect the busbar switch (8) and control switch (12); Close the DC switch (211).

7. The control method for a flow battery according to claim 4, characterized in that, When a single fuel cell stack (22) or a single voltage conversion circuit (21) fails, the method includes: By switching the bus switch (8), a single faulty device is disconnected, and non-faulty devices are connected to other energy storage units (2) to continue operation.

8. The control method for a flow battery according to claim 4, characterized in that, When the voltage of the fuel cell stack (22) is inconsistent, the process of maintaining the stable operation of the second DC bus (4) includes: The multi-port DC-DC converter (11) is controlled to charge the voltage of the stack (22) to a preset voltage threshold.

9. The control method for a flow battery according to claim 4, characterized in that, When a black start is required due to a power outage in the AC system or in an emergency, the method includes: Disconnect the control switch (12) and close a preset number of bus switches (8); The control energy storage battery (5) supplies power to the DC load (6) through the multi-port DC-DC converter (11), while a preset number of battery stacks (22) are charged.

10. A control device for a flow battery, characterized in that, The device includes: The first control module is used to control the on / off states of the bus switch (8), DC switch (211), and control switch (12) based on the voltage state of the first DC bus and the second DC bus (4), the charge state of the energy storage battery (5), and the power demand of the DC load (6), so as to reconstruct the electrical connection relationship between the first DC bus and the second DC bus (4), control the working mode of the multi-port DC-DC converter (11), and realize the directional flow and transformation of energy between the grid side, the flow battery side, the energy storage battery (5) side, and the load side. The second control module is used to monitor the operating parameters of each flow battery stack (22) and selectively engage or disengage the target flow battery stack through the DC switch (211) group to maintain the stable operation of the second DC bus (4).

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