Group string type liquid flow energy storage system and control method thereof

Abstract

The invention discloses a string type liquid flow energy storage system and a control method thereof, and belongs to the technical field of energy storage, and the system comprises a liquid path subsystem which is formed by connecting multiple electric piles in series; the BCU is connected with the liquid path subsystem and used for regulating and controlling the operation state of the liquid path subsystem; the PCS is connected with the BCU and used for controlling the energy output by the liquid path subsystem; the BAU is connected with the PCSs and the BCUs and used for receiving data reported by the PCSs and the BCUs and controlling the operation states of the liquid path subsystems according to instructions sent by the EMS; and the EMS is connected with the BAU and is used for managing and controlling each BCU, each PCS, the BAU and each liquid path subsystem according to a user instruction and data reported by the BAU. By means of the system, the barrel effect and the circulation phenomenon of the liquid flow energy storage system can be avoided, and the operation and maintenance cost and the power loss of the liquid flow energy storage system are reduced.

Description

Technical Field

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

[0002] Centralized flow battery energy storage systems (HLBES) are widely used in large-scale wind and solar power plants and independent energy storage applications due to their advantages such as long storage time and large storage capacity. However, because the individual fuel cells in a centralized HLBES system are directly connected in parallel, the following problems arise:

[0003] First, because the fuel cells in a centralized flow fuel cell system are connected in parallel, the output voltage of each fuel cell is forced to be balanced. As a result, the overall lifespan of the centralized flow fuel cell system depends on the fuel cell with the shortest lifespan, and the barrel effect is obvious.

[0004] Second, the inconsistent discharge depth of each stack in a centralized flow fuel cell system may lead to circulating currents. This will not only affect the charging and discharging efficiency of the centralized flow fuel cell system, but also pose significant safety hazards.

[0005] Third, when a fuel cell stack in a centralized flow fuel cell system fails, because all the stacks within it are connected in parallel, repairing the entire system requires powering off to access the faulty stack, resulting in a wide-ranging impact. Furthermore, the maintenance and commissioning process for centralized flow fuel cell systems is complex, sometimes requiring on-site repairs by the manufacturer, leading to long maintenance cycles and high operating costs.

[0006] Fourth, because all the fuel cells in a centralized flow fuel cell system are connected in parallel, the output current of the centralized flow fuel cell system is relatively large, which in turn leads to higher power loss in the centralized flow fuel cell system.

[0007] Therefore, how to avoid the barrel effect and circulation phenomenon in flow energy storage systems, and reduce the operation and maintenance costs and power loss of flow energy storage systems, are technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0008] In view of this, the purpose of this invention is to provide a string flow energy storage system and its control method to avoid the bottleneck effect and circulation phenomenon in the flow energy storage system, and to reduce the operation and maintenance costs and power loss of the flow energy storage system. The specific solution is as follows:

[0009] To address the aforementioned technical problems, this invention provides a string-type flow energy storage system, comprising:

[0010] The liquid circuit subsystem is composed of The system consists of several fuel cells connected in series, which are used to deliver electrolyte to each fuel cell through liquid pipelines so that each fuel cell can convert the chemical energy of the electrolyte into electrical energy. ;

[0011] The BCU is connected to the liquid circuit subsystem and is used to acquire the operating data of the liquid circuit subsystem and regulate the operating status of the liquid circuit subsystem.

[0012] PCS, connected to the BCU, is used to control the energy output by the liquid circuit subsystem;

[0013] BAU is connected to multiple PCS and multiple BCUs, and is used to receive data reported by each PCS and each BCU, and to control the operating status of each liquid circuit subsystem according to the instructions issued by EMS.

[0014] The EMS is connected to the BAU and is used to control each BCU, each PCS, the BAU and each liquid circuit subsystem according to user instructions and data reported by the BAU.

[0015] Preferably, the fluid circuit subsystem includes: A series of interconnected components including a fuel cell stack, a positive contactor, a negative contactor, a positive electrode liquid storage tank, a negative electrode liquid storage tank, a positive electrode pump, a negative electrode pump, a positive electrode valve module, a negative electrode valve module, a positive electrode liquid circuit detection module, a negative electrode liquid circuit detection module, a positive electrode constant temperature module, and a negative electrode constant temperature module.

[0016] in, The positive output terminal of each series-connected fuel cell stack is connected to the first terminal of the positive contactor, and the second terminal of the positive contactor is connected to the PCS. The negative output terminal of each series-connected fuel cell stack is connected to the first terminal of the negative contactor, and the second terminal of the negative contactor is connected to the PCS.

[0017] In the series-connected stacks, the first The second positive electrode liquid flow port of the fuel cell stack is connected to the first The first positive electrode liquid flow port of the stack is connected, the second The second negative electrode liquid flow port of the fuel cell stack is connected to the first The first negative electrode liquid flow port of each fuel cell stack is connected. The first positive electrode liquid flow port of the first fuel cell stack connects to the first positive electrode through the positive electrode liquid path detection module, the positive electrode pump, the positive electrode constant temperature module, and the positive electrode valve module. The second positive electrode liquid flow port of the first fuel cell stack is connected; the first negative electrode liquid flow port of the first fuel cell stack is connected to the second positive electrode liquid flow port through the negative electrode liquid path detection module, the negative electrode pump, the negative electrode constant temperature module, and the negative electrode valve module. The second negative electrode liquid flow port of each fuel cell stack is connected;

[0018] The positive electrode liquid path detection module is used to detect inflow and outflow in the positive electrode liquid path circuit. The electrolyte parameters of the interconnected fuel cell stacks are detected; the negative electrode liquid path detection module is used to detect the inflow and outflow in the negative electrode liquid path circuit. The electrolyte parameters of the interconnected battery stacks are detected; the positive electrode constant temperature module and the negative electrode constant temperature module are used to keep the positive electrode storage tank and the negative electrode storage tank warm or cool them, so that the temperature of the positive electrode storage tank and the negative electrode storage tank is kept within a preset range; the positive electrode valve module and the negative electrode valve module are used to control the electrolyte flowing through the positive electrode pump and the negative electrode pump, respectively.

[0019] Preferably, the positive electrode liquid circuit detection module includes:

[0020] A positive electrode inlet temperature sensor is used to detect the temperature of the liquid flowing into the positive electrode circuit. The temperature of the electrolyte in the series-connected fuel cells is monitored.

[0021] Positive electrode inlet pressure sensor; used to monitor the inflow of liquid into the positive electrode liquid circuit. The pressure of the electrolyte in the series-connected fuel cells is monitored.

[0022] Positive electrode inlet flow sensor; used to detect the inflow into the positive electrode liquid circuit. The flow rate of electrolyte in a series-connected stack is detected.

[0023] Positive electrode return temperature sensor; used to monitor the temperature of the outflowing liquid in the positive electrode liquid circuit. The temperature of the electrolyte in the series-connected fuel cells is monitored.

[0024] Accordingly, the negative electrode liquid circuit detection module includes:

[0025] A negative electrode inlet temperature sensor is used to detect the temperature of the liquid flowing into the negative electrode circuit. The temperature of the electrolyte in the series-connected fuel cells is monitored.

[0026] Negative electrode inlet pressure sensor; used to monitor the inflow of liquid into the negative electrode liquid circuit. The pressure of the electrolyte in the series-connected fuel cells is monitored.

[0027] Negative electrode inlet flow sensor; used to measure the flow rate of liquid entering the negative electrode in the negative electrode liquid circuit. The flow rate of electrolyte in a series-connected stack is detected.

[0028] Negative electrode return temperature sensor; used to monitor the temperature of the outflowing liquid in the negative electrode liquid circuit. The temperature of the electrolyte in the series-connected fuel cell stacks was measured.

[0029] Preferably, the positive electrode valve module includes: a positive electrode return valve and a positive electrode mixing valve; the negative electrode valve module includes: a negative electrode return valve and a negative electrode mixing valve;

[0030] The positive electrode return valve is connected to the positive electrode storage tank and the first... Between the second positive electrode liquid flow port of the fuel cell stack; the negative electrode return valve is connected between the negative electrode liquid storage tank and the first... Between the second negative electrode liquid flow ports of the fuel cell stacks; the positive electrode mixing valve is connected between the positive electrode return valve and the negative electrode return valve; the negative electrode mixing valve is connected between the negative electrode return valve and the positive electrode return valve.

[0031] To address the aforementioned technical problems, this invention also provides a control method for a string flow energy storage system, applied to a target BCU in the aforementioned disclosed string flow energy storage system; the target BCU is any one of a plurality of BCUs, including:

[0032] Monitor BAU;

[0033] When the BAU receives the target instruction issued by the EMS, it determines whether the target fluid circuit subsystem is in normal operating condition; the target fluid circuit subsystem is the fluid circuit subsystem connected to the target BCU.

[0034] If so, the operating state of the target liquid circuit subsystem is controlled to respond to the target command.

[0035] Preferably, determining whether the target fluid circuit subsystem is in normal operating condition includes:

[0036] When the main switch of the BAU is closed, it is determined whether the total load pressure of the target fluid circuit subsystem is normal.

[0037] If so, determine whether the positive and negative voltages to ground, output voltage, open circuit voltage, liquid pressure signal, and fire alarm signal of the target liquid circuit subsystem are all normal;

[0038] If so, determine whether the SOH of the target liquid circuit subsystem is greater than a preset threshold;

[0039] If so, determine whether the temperatures of the positive electrode storage tank and the negative electrode storage tank in the target liquid circuit subsystem are within the preset range;

[0040] If so, the target liquid circuit subsystem is determined to be in normal operating condition.

[0041] Preferably, controlling the operating state of the target fluid circuit subsystem to respond to the target command includes:

[0042] The positive return valve and negative return valve in the target liquid circuit subsystem are opened, and the positive pump and negative pump in the target liquid circuit subsystem are started and run.

[0043] Control the closure of the positive and negative contactors in the target liquid circuit subsystem;

[0044] The target instruction is parsed to obtain target parsing data, and the operating speed of the positive and negative pumps in the target liquid circuit subsystem is controlled according to the target parsing data, so as to control the output current of the target liquid circuit subsystem.

[0045] Preferably, controlling the operating speeds of the positive and negative pumps in the target liquid circuit subsystem based on the target analysis data to control the output current of the target liquid circuit subsystem includes:

[0046] The flow rate of the electrolyte in the target liquid circuit subsystem and the output current of the target liquid circuit subsystem are detected respectively.

[0047] Based on the target analysis data, and according to the flow rate of the electrolyte in the target liquid circuit subsystem and the output current of the target liquid circuit subsystem, the operating speed of the positive and negative pumps in the target liquid circuit subsystem is adjusted.

[0048] Preferred options also include:

[0049] During the process of controlling the output current of the target liquid circuit subsystem, the voltage of the target individual electrode is detected by the target BMU; the target individual electrode is any individual electrode in the target stack; the target stack is any stack in the target liquid circuit subsystem; the target BMU is the BMU connected to the target individual electrode.

[0050] When the target command is a discharge command, it is determined whether the voltage of the target single electrode is lower than a first preset threshold.

[0051] If so, then control the target single electrode to stop discharging, and control the positive and negative pumps in the target liquid circuit subsystem to stop operating;

[0052] If not, continue with the step of controlling the operating speed of the positive and negative pumps in the target liquid circuit subsystem based on the target analysis data, so as to control the output current of the target liquid circuit subsystem;

[0053] When the target instruction is a charging instruction, it is determined whether the voltage of the target single electrode is higher than the second preset threshold.

[0054] If so, then control the target single electrode to stop charging, and control the positive and negative pumps in the target liquid circuit subsystem to stop running;

[0055] If not, continue with the step of controlling the operating speed of the positive and negative pumps in the target liquid circuit subsystem based on the target analysis data, so as to control the output current of the target liquid circuit subsystem.

[0056] Preferred options also include:

[0057] The target BMU detects the current and temperature data of the target single electrode, and inputs the current and temperature data of the target single electrode into a preset model to determine whether the target single electrode has a fault.

[0058] The creation process of the preset model includes:

[0059] The current and temperature data corresponding to the target single electrode under normal operation and fault conditions are obtained in advance, and the preset model is created based on the current and temperature data corresponding to the target single electrode under normal operation and fault conditions using artificial intelligence algorithms.

[0060] Beneficial Effects: In the string flow fuel cell energy storage system provided by this invention, the fuel cell stacks in the flow fuel cell energy storage system are divided into multiple liquid circuit subsystems, and the multiple fuel cell stacks in each liquid circuit subsystem are connected in series. With this architecture, a single BCU can manage and control the fuel cell stacks in one liquid circuit subsystem. This not only improves the charging and discharging efficiency of the fuel cell stacks but also makes the output current of each liquid circuit subsystem more balanced, thereby avoiding the "weakest link" effect and circulating current phenomenon in the flow fuel cell energy storage system. Furthermore, since each liquid circuit subsystem is controlled by a single BCU, when a faulty fuel cell stack occurs in the flow fuel cell energy storage system, the faulty stack can be directly disconnected and the fault isolated. This not only reduces the operation and maintenance complexity of the flow fuel cell energy storage system but also reduces the required operation and maintenance costs. In addition, since the fuel cell stacks in each liquid circuit subsystem are connected in series, the output current of this circuit architecture is relatively smaller for the same energy storage capacity, thereby significantly reducing the power loss of the flow fuel cell energy storage system.

[0061] Correspondingly, the control method for a string flow energy storage system provided by the present invention also has the above-mentioned beneficial effects. Attached Figure Description

[0062] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0063] Figure 1 This is a structural diagram of a string flow energy storage system provided in an embodiment of the present invention;

[0064] Figure 2 This is a structural diagram of a single liquid circuit subsystem provided in an embodiment of the present invention;

[0065] Figure 3 A structural diagram of a string flow energy storage system with two liquid circuit subsystems;

[0066] Figure 4 A structural diagram showing the configuration of two liquid circuit subsystems in a centralized liquid flow energy storage system;

[0067] Figure 5 A flowchart of a control method for a string flow energy storage system provided in an embodiment of the present invention;

[0068] Figure 6 A flowchart for determining whether a target liquid circuit subsystem is in normal operating condition is provided in an embodiment of the present invention;

[0069] Figure 7 This is a flowchart illustrating the control of a target liquid circuit subsystem according to an embodiment of the present invention. Detailed Implementation

[0070] 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, and 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.

[0071] Please see Figure 1 , Figure 1 This is a structural diagram of a string flow energy storage system provided in an embodiment of the present invention. The system includes:

[0072] Liquid circuit subsystem 11, consisting of It consists of several fuel cells connected in series, which are used to deliver electrolyte to each fuel cell through liquid pipelines so that each fuel cell can convert the chemical energy of the electrolyte into electrical energy. ;

[0073] BCU12 is connected to the liquid circuit subsystem 11 and is used to acquire the operating data of the liquid circuit subsystem 11 and regulate the operating status of the liquid circuit subsystem 11.

[0074] PCS13, connected to BCU12, is used to control the energy output by the liquid circuit subsystem 11;

[0075] BAU14 is connected to multiple PCS13 and multiple BCU12, and is used to receive data reported by each PCS13 and each BCU12, and to control the operating status of each liquid circuit subsystem 11 according to the instructions issued by EMS15.

[0076] EMS15, connected to BAU14, is used to control each BCU12, each PCS13, BAU14 and each liquid circuit subsystem 11 according to user instructions and data reported by BAU14.

[0077] To enable those skilled in the art to more clearly understand the implementation principle of this application, a brief introduction is given here of the advantages of existing fluid energy storage systems:

[0078] First, long service life. Because flow battery systems utilize electrodes within their internal fuel cell stack as reaction carriers, and the stack itself does not participate in the chemical reaction, their service life is exceptionally long. For example, a vanadium redox flow battery stack can achieve an astonishing 16,000 cycles, far exceeding the 2,000-3,000 cycles of lithium-ion battery stacks, with a service life exceeding 20 years. This means that throughout the entire lifespan of a vanadium redox flow battery stack, it does not require frequent replacement of its internal components. This not only reduces maintenance costs but also significantly extends its service life.

[0079] Second, safety and reliability. Flow hydride energy storage systems use electrolyte as the source of electrical energy. Electrolytes are not easily flammable or explosive, thus preventing safety accidents and providing a solid technical foundation for the safe and stable operation of the energy storage system. Furthermore, this characteristic of flow hydride energy storage systems is particularly important for large-scale energy storage projects, as it can significantly reduce the probability of safety accidents occurring in the energy storage system.

[0080] Third: Long energy storage time. In flow hydride energy storage systems, the power and capacity of the fuel cell stack are decoupled. The power of the stack is determined by the stack itself, while the capacity is determined by the electrolyte inside. This results in a significantly longer energy storage time compared to other energy storage module structures. This characteristic of flow hydride energy storage systems effectively addresses the current fluctuations and intermittent power generation issues associated with renewable energy sources such as wind and solar power. Furthermore, during peak electricity demand periods, flow hydride energy storage systems can provide a stable supply of power to the grid.

[0081] Fourth: Environmentally friendly. Taking the all-vanadium redox flow stack as an example, the active material of its internal electrolyte is all vanadium ions. This not only avoids the problem of cross-contamination of metal ions, but also allows the electrolyte to be recycled and reused, thus effectively reducing resource consumption and potential environmental impact.

[0082] Due to the aforementioned advantages of flow storage systems, they have a very broad application prospect in practical applications. This application provides a string flow storage system. Utilizing this architecture, the flow storage system can not only avoid the "weakest link" effect and circulation phenomena that often occur in flow storage systems, but also reduce the operation and maintenance costs and power loss of the flow storage system.

[0083] In the string flow fuel cell energy storage system provided in this application, the EMS (Energy Management System) is the highest-level management controller. It can make optimal energy dispatch decisions by combining grid demand and user commands, and achieve safe and efficient operation of the flow fuel cell energy storage system. The BAU (Battery Array Unit) is used to receive commands issued by the EMS and is responsible for managing all liquid circuit subsystems in the flow fuel cell energy storage system. It is also responsible for managing the data interaction between each liquid circuit subsystem and its corresponding PCS (Power Conversion System) and BCU (Battery Control Unit).

[0084] In the liquid circuit subsystem, the internal fuel cells are connected in series. Furthermore, the liquid circuit subsystem delivers electrolyte to each fuel cell stack through liquid circuit pipelines, enabling each fuel cell stack to convert the chemical energy of the electrolyte into electrical energy.

[0085] In string flow fuel cell systems, because the fuel cells in each flow circuit subsystem are connected in series, this architecture allows a single Base Unit (BCU) to manage and control the fuel cells in one flow circuit subsystem. This gives string flow fuel cell systems the following advantages:

[0086] First, it allows for a more flexible circuit architecture for flow hydride energy storage systems and facilitates their expansion. This distributed architecture makes flow hydride energy storage systems suitable for applications such as wind-solar-storage integration, grid-connected and off-grid applications, and long-term energy storage. Furthermore, the circuit architecture of string flow hydride energy storage systems can more accurately match the energy storage duration and power requirements of different application scenarios, thereby improving the overall operating efficiency of the energy storage system.

[0087] Secondly, when a flow liquefaction energy storage system malfunctions, the faulty fluid circuit subsystem can be quickly and accurately located. To isolate the fault, only the affected subsystem needs to be disconnected, thus rapidly isolating the faulty area and ensuring the safe and stable operation of other parts of the system. Simultaneously, this fault isolation method effectively reduces the risk of thermal runaway in flow liquefaction energy storage systems and prevents its spread and large-scale fires, significantly reducing the downtime risk.

[0088] Furthermore, this modular design effectively simplifies the operation and maintenance process for flow storage systems, improving the speed and accuracy of fault location. In this scenario, maintenance personnel can also replace faulty components more quickly, reducing downtime and lowering maintenance costs.

[0089] Third, the string flow fuel cell system adopts a fluidized bed subsystem design, where each subsystem is independent and does not affect the others, offering advantages such as convenient transportation and quick installation. This design architecture is not only suitable for various application scenarios but also supports the mixing of new and old fuel cell stacks. Furthermore, staff can expand the capacity and replenish the fluid in the string flow fuel cell system according to actual conditions and needs, greatly improving the flexibility and maintainability of the system.

[0090] Fourth, string flow fuel cell systems employ a single battery control unit (BCU) managing one flow circuit subsystem. This not only improves stack balance and charge / discharge efficiency but also avoids circulating currents, preventing issues like cell mismatch caused by circulating currents. Because there are no circulating currents in string flow fuel cell systems, capacity decay in a single flow circuit subsystem only affects the performance of that subsystem, having a smaller impact on the overall charge / discharge efficiency of the system. This results in a longer cycle life and higher yield. Furthermore, the absence of circulating currents significantly extends the lifespan of the fuel cell stack, further enhancing the stability of the flow fuel cell system during operation.

[0091] Fifth, string flow storage systems can help increase the proportion of new energy grid connection and consumption. Experimental data shows that the operating performance of string flow storage systems meets engineering requirements and exceeds the current level in the industry.

[0092] Compared to existing technologies, the string flow fuel cell system provided in this embodiment divides the fuel cell stack into multiple liquid path subsystems, with the fuel cell stacks in each liquid path subsystem connected in series. This architecture allows a single circuit control unit (BCU) to manage and control the fuel cell stacks in one liquid path subsystem. This not only improves the charging and discharging efficiency of the fuel cell stacks but also ensures a more balanced output current across the various liquid path subsystems, thus avoiding the "weakest link" effect and circulating current phenomena in the flow fuel cell system. Furthermore, since each liquid path subsystem is controlled by a single BCU, when a fuel cell stack malfunctions, it can be directly disconnected and the fault isolated. This reduces both the complexity and cost of operation and maintenance for the flow fuel cell system. Additionally, because the fuel cell stacks in each liquid path subsystem are connected in series, the output current of this circuit architecture is relatively smaller for the same energy storage capacity, thereby significantly reducing the power loss of the flow fuel cell system.

[0093] Based on the above embodiments, this embodiment further explains and optimizes the technical solution. Please refer to [link / reference]. Figure 2 , Figure 2 This is a structural diagram of a single fluid circuit subsystem provided in an embodiment of the present invention. As a preferred embodiment, the fluid circuit subsystem includes: A series of interconnected components including a fuel cell stack, a positive contactor 100, a negative contactor 200, a positive electrode liquid storage tank 106, a negative electrode liquid storage tank 206, a positive electrode pump 105, a negative electrode pump 205, a positive electrode valve module, a negative electrode valve module, a positive electrode liquid circuit detection module, a negative electrode liquid circuit detection module, a positive electrode constant temperature module, and a negative electrode constant temperature module.

[0094] in, The positive output terminal of the series-connected fuel cells is connected to the first terminal of the positive contactor 100, and the second terminal of the positive contactor 100 is connected to the PCS. The negative output terminal of the series-connected stacks is connected to the first terminal of the negative contactor 200, and the second terminal of the negative contactor 200 is connected to the PCS.

[0095] In the series-connected stacks, the first The second positive electrode liquid flow port of the fuel cell stack is connected to the first The first positive electrode liquid flow port of the stack is connected, the second The second negative electrode liquid flow port of the fuel cell stack is connected to the first The first negative electrode liquid flow port of each fuel cell stack is connected. The first positive electrode liquid flow port of the first fuel cell stack is connected to the first positive electrode liquid circuit detection module, positive electrode pump 105, positive electrode constant temperature module and positive electrode valve module. The second positive electrode liquid flow port of the first fuel cell stack is connected; the first negative electrode liquid flow port of the first fuel cell stack is connected to the second positive electrode liquid flow port of the first fuel cell stack through the negative electrode liquid circuit detection module, the negative electrode pump 205, the negative electrode constant temperature module and the negative electrode valve module. The second negative electrode liquid flow port of each fuel cell stack is connected;

[0096] The positive electrode liquid circuit detection module is used to detect the inflow and outflow in the positive electrode liquid circuit. The electrolyte parameters of the interconnected fuel cell stacks are monitored; the negative electrode liquid circuit detection module is used to monitor the inflow and outflow of electrolyte in the negative electrode liquid circuit. The electrolyte parameters of the interconnected fuel cells are detected; the positive electrode constant temperature module and the negative electrode constant temperature module are used to keep the positive electrode storage tank 106 and the negative electrode storage tank 206 warm or cool, so that the temperature of the positive electrode storage tank 106 and the negative electrode storage tank 206 is kept within a preset range; the positive electrode valve module and the negative electrode valve module are used to control the electrolyte flowing through the positive electrode pump 105 and the negative electrode pump 205, respectively.

[0097] As a preferred embodiment, the positive electrode liquid circuit detection module includes:

[0098] Positive electrode inlet temperature sensor 101 is used to detect the temperature of the liquid flowing into the positive electrode circuit. The temperature of the electrolyte in the series-connected fuel cells is monitored.

[0099] Positive electrode inlet pressure sensor 102; used to monitor the inflow of liquid into the positive electrode liquid circuit. The pressure of the electrolyte in the series-connected fuel cells is monitored.

[0100] Positive electrode inlet flow sensor 103; used to monitor the inflow into the positive electrode liquid circuit. The flow rate of electrolyte in a series-connected stack is detected.

[0101] Positive electrode return temperature sensor 109; used to monitor the temperature of the outflowing liquid in the positive electrode liquid circuit. The temperature of the electrolyte in the series-connected fuel cells is monitored.

[0102] Correspondingly, the negative electrode liquid circuit detection module includes:

[0103] The negative electrode inlet temperature sensor 201 is used to detect the temperature of the liquid flowing into the negative electrode liquid circuit. The temperature of the electrolyte in the series-connected fuel cells is monitored.

[0104] Negative electrode inlet pressure sensor 202; used to monitor the pressure of liquid flowing into the negative electrode liquid circuit. The pressure of the electrolyte in the series-connected fuel cells is monitored.

[0105] Negative electrode inlet flow sensor 203; used to monitor the inflow of liquid into the negative electrode liquid circuit. The flow rate of electrolyte in a series-connected stack is detected.

[0106] Negative electrode return temperature sensor 209; used to monitor the temperature of the outflowing liquid in the negative electrode liquid circuit. The temperature of the electrolyte in the series-connected fuel cell stacks was measured.

[0107] In a preferred embodiment, the positive electrode valve module includes: a positive electrode return valve 107 and a positive electrode mixing valve 108; the negative electrode valve module includes: a negative electrode return valve 207 and a negative electrode mixing valve 208.

[0108] Among them, the positive electrode return valve 107 is connected to the positive electrode storage tank 106 and the first Between the second positive electrode liquid flow port of the fuel cell stack; the negative electrode return valve 207 is connected between the negative electrode liquid storage tank 206 and the first... Between the second negative electrode liquid flow ports of the fuel cell stacks; the positive electrode mixing valve 108 is connected between the positive electrode return valve 107 and the negative electrode return valve 207; the negative electrode mixing valve 208 is connected between the negative electrode return valve 207 and the positive electrode return valve 107.

[0109] This embodiment provides a detailed description of the structure of a single liquid circuit subsystem. Figure 2 The liquid circuit subsystem shown actually contains three loops, one of which is... An electrical circuit consisting of fuel cells connected in series ( Figure 2 (Red line in the middle); one line is... The positive electrode liquid circuit consists of a fuel cell stack, a positive electrode inlet temperature sensor 101, a positive electrode inlet pressure sensor 102, a positive electrode inlet flow sensor 103, a positive electrode chiller 104, a positive electrode pump 105, a positive electrode storage tank 106, a positive electrode return valve 107, a positive electrode mixing valve 108, and a positive electrode return temperature sensor 109. Figure 2 (The yellow line in the image); the other line is... The negative electrode liquid circuit consists of a fuel cell stack, a negative electrode inlet temperature sensor 201, a negative electrode inlet pressure sensor 202, a negative electrode inlet flow sensor 203, a negative electrode chiller 204, a negative electrode pump 205, a negative electrode storage tank 206, a negative electrode return valve 207, a negative electrode mixing valve 208, and a negative electrode return temperature sensor 209. Figure 2 (The blue line in the middle).

[0110] It should be noted that the surfaces of the positive electrode storage tank 106 and the negative electrode storage pipe 206 are also covered with heating tapes. In the positive electrode liquid circuit, the interaction between the chiller 105 and the heating tapes on the positive electrode storage tank 106 ensures that the temperature of the positive electrode storage tank is maintained within a preset range. In the negative electrode liquid circuit, the interaction between the chiller 205 and the heating tapes on the negative electrode storage tank 206 ensures that the temperature of the negative electrode storage tank is maintained within a preset range. Specifically, the chiller 105 and the heating tapes on the positive electrode storage tank 106 constitute a positive electrode constant temperature module, while the chiller 205 and the heating tapes on the negative electrode storage tank 206 constitute a negative electrode constant temperature module.

[0111] exist Figure 2 In this system, a positive electrode liquid path detection module is composed of a positive electrode inlet liquid temperature sensor 101, a positive electrode inlet liquid pressure sensor 102, a positive electrode inlet liquid flow sensor 103, and a positive electrode return liquid temperature sensor 109, while a negative electrode liquid path detection module is composed of a negative electrode inlet liquid temperature sensor 201, a negative electrode inlet liquid pressure sensor 202, a negative electrode inlet liquid flow sensor 203, and a negative electrode return liquid temperature sensor 209.

[0112] It should be noted that when the electrolyte flows back... In the process of connecting interconnected fuel cell stacks, the flow rate and pressure of the electrolyte have relatively little impact on the overall energy conversion process of the fluidized bed energy storage system. Therefore, in order to reduce the design cost of the fluidized bed energy storage system, it is not necessary to include electrolyte return circuits. Flow sensors and pressure sensors are installed on the section of pipeline where the fuel cells are connected in series.

[0113] In the electrolyte circuit subsystem, the positive electrode return valve 107, the negative electrode return valve 207, the positive electrode mixing valve 108, and the negative electrode mixing valve 208 are key components in the electrolyte circulation pipeline. In the positive electrode liquid circuit, the coordinated operation of the positive electrode mixing valve 108 and the positive electrode return valve 107 ensures normal circulation and state balance of the electrolyte. Similarly, in the negative electrode liquid circuit, the coordinated operation of the negative electrode mixing valve 208 and the negative electrode return valve 207 ensures normal circulation and state balance of the electrolyte.

[0114] The positive electrode mixing valve 108 and the negative electrode mixing valve 208 are mainly used for cross-mixing the electrolytes in the positive electrode storage tank 106 and the negative electrode storage tank 206. The positive electrode return valve 107 mainly controls the return of electrolyte in the positive electrode liquid circuit from the fuel cell stack to the positive electrode storage tank 106. Furthermore, when the positive electrode inlet pressure sensor 102 detects an imbalance in the liquid pressure in the positive electrode liquid circuit, the positive electrode return valve 107 can also quickly balance the pressure in the positive electrode liquid circuit by releasing a portion of the electrolyte back to the positive electrode storage tank 106, thereby ensuring the safety of the pipeline and the fuel cell stack. Similarly, the negative electrode return valve 207 mainly controls the return of electrolyte in the negative electrode liquid circuit from the fuel cell stack to the negative electrode storage tank 206. Furthermore, when the negative electrode inlet pressure sensor 202 detects an imbalance in the liquid pressure in the negative electrode liquid circuit, the negative electrode return valve 207 can also quickly balance the pressure in the negative electrode liquid circuit by releasing a portion of the electrolyte back to the negative electrode storage tank 206, thereby ensuring the safety of the pipeline and the fuel cell stack.

[0115] In practical applications, an expansion board can be connected to each liquid circuit subsystem to convert the analog signals detected by the sensors in the positive and negative electrode liquid circuit detection modules into digital signals. Once the expansion board has converted the analog signals detected by the sensors in the positive and negative electrode liquid circuit detection modules into digital signals, this data can be reported to the BCU for processing.

[0116] In addition, in practical applications, it can also be used in A fuse and a fire-fighting device are connected between the positive output terminal of each series-connected fuel cell stack and the positive contactor, and... Each series-connected fuel cell stack has a fuse and a fire suppression system connected between its negative output terminal and the negative contactor. This configuration effectively establishes a separate thermal management system and fire suppression system for each liquid circuit subsystem. This not only effectively reduces the risk of thermal runaway in the liquid circuit subsystem but also prevents the spread of thermal runaway and large-scale fires.

[0117] Here, two liquid circuit subsystems are set up in the string flow energy storage system and the centralized flow energy storage system respectively, so that those skilled in the art can understand the structural differences between the string flow energy storage system and the centralized flow energy storage system from a macroscopic perspective.

[0118] Please see Figure 3 and Figure 4 , Figure 3 This is a structural diagram of a string flow energy storage system with two liquid circuit subsystems. Figure 4 This is a structural diagram showing the configuration of two liquid circuit subsystems in a centralized liquid flow energy storage system. Figure 3 and Figure 4 In the diagram, the reference numerals for each component are... Figure 2 The reference numerals in the accompanying drawings are consistent and will not be repeated here. Figure 3 In this case, multiple fuel cells in each liquid circuit subsystem are configured in series, while... Figure 4 In this case, multiple fuel cells in each liquid circuit subsystem are configured in parallel.

[0119] contrast Figure 3 and Figure 4 It is evident that string flow storage systems (FLS) allow for a more flexible and easily expandable circuit architecture. When a FLS system fails, the faulty fluid circuit subsystem can be quickly disconnected, rapidly isolating the faulty area and ensuring the safe and stable operation of other parts of the system. The modular design of FLS effectively simplifies the maintenance process for operators, improving the speed and accuracy of fault location. Furthermore, the use of one BCU managing one fluid circuit subsystem in FLS improves stack balance and charging / discharging efficiency, avoids circulating currents, and extends service life.

[0120] Please see Figure 5 , Figure 5 This is a flowchart of a control method for a string flow energy storage system provided in an embodiment of the present invention. The method is applied to a target BCU in the aforementioned disclosed string flow energy storage system; the target BCU is any one of a plurality of BCUs. The method includes:

[0121] Step S11: Monitor BAU;

[0122] Step S12: When the target instruction issued by the EMS is received through the BAU, it is determined whether the target fluid circuit subsystem is in normal operating condition; the target fluid circuit subsystem is the fluid circuit subsystem connected to the target BCU; if so, step S13 is executed.

[0123] Step S13: Control the operating status of the target liquid circuit subsystem to respond to the target command.

[0124] This embodiment provides a control method for a string flow fuel cell energy storage system. This method can control the string flow fuel cell energy storage system to perform grid connection and charging / discharging operations. The method is specifically described using a target BCU as the execution subject. The target BCU refers to the BCU corresponding to any one of the fluid circuit subsystems in the string flow fuel cell energy storage system. That is, in the string flow fuel cell energy storage system, the action logic executed by each fluid circuit subsystem is consistent.

[0125] In this control method, the target BCU monitors the BAU. When the target BCU receives a target command from the BAU, it indicates that the highest management controller (EMS) in the string flow energy storage system has sent a target command to the BAU. At this time, the target BCU determines whether the target fluid circuit subsystem is in normal operating condition, and uses this to determine whether the string flow energy storage system meets the prerequisites for performing charging and discharging operations.

[0126] When the target BCU determines that the target liquid circuit subsystem is in normal operating condition, it means that all liquid circuit subsystems in the string liquid flow energy storage system are in normal operating condition, and the entire string liquid flow energy storage system is in normal operating condition. At this time, the target BCU will control the operating status of the target liquid circuit subsystem to achieve the purpose of responding to the target command.

[0127] Obviously, the technical solution provided in this embodiment can achieve the purpose of controlling the string flow energy storage system.

[0128] Based on the above embodiments, this embodiment further explains and optimizes the technical solution. Please refer to [link / reference]. Figure 6 , Figure 6 This invention provides a flowchart for determining whether a target fluid circuit subsystem is in normal operating condition. As a preferred embodiment, the step of determining whether the target fluid circuit subsystem is in normal operating condition includes:

[0129] Step 201: When the main switch of BAU is closed, determine whether the total load pressure of the target hydraulic circuit subsystem is normal; if so, proceed to step S202.

[0130] Step 202: Determine whether the positive and negative terminal voltages to ground, output voltage, open circuit voltage, liquid pressure signal, and fire alarm signal of the target liquid circuit subsystem are all normal; if so, proceed to step S203.

[0131] Step 203: Determine whether the SOH of the target liquid circuit subsystem is greater than the preset threshold; if so, proceed to step S204.

[0132] Step S204: Determine whether the temperatures of the positive electrode storage tank and the negative electrode storage tank in the target liquid circuit subsystem are within the preset range; if so, proceed to step S205.

[0133] Step S205: Determine that the target liquid circuit subsystem is in normal operating condition.

[0134] Before controlling the target fluid circuit subsystem, it is essential to ensure that the target fluid circuit subsystem is in a normal operating state to guarantee the safe and stable operation of the string fluid energy storage system. This embodiment provides a specific method for determining whether the target fluid circuit subsystem is in a normal operating state.

[0135] The target BCU first checks whether the total load pressure of the target liquid circuit subsystem is normal when the main switch of the BAU is closed. If the total load pressure of the target liquid circuit subsystem is normal, it indicates that the fuel cell power supply of the target liquid circuit subsystem is basically normal and the power supply circuit is complete. At this time, the target BCU will continue to check whether the positive and negative terminal voltages to ground, output voltages, open circuit voltages, liquid pressure signals, and fire alarm signals of the target liquid circuit subsystem are all normal.

[0136] The normal positive-to-ground and negative-to-ground voltages of the target liquid circuit subsystem indicate good insulation performance in the positive and negative circuits. A normal output voltage indicates the subsystem can output a stable rated voltage under load, and the electrolyte in both the positive and negative circuits is circulating normally. A normal open-circuit voltage indicates the fuel cell stack's open-circuit voltage matches the theoretical output value under static conditions, and the chemical state of the electrolyte in both circuits is essentially normal. A normal liquid pressure signal indicates no significant blockage in the pipes of both the positive and negative circuits. A normal fire alarm signal indicates the fire suppression system is functioning normally.

[0137] When the target BCU determines that the positive and negative voltages to ground, output voltage, open circuit voltage, liquid pressure signal, and fire alarm signal of the target liquid circuit subsystem are all normal, the target BCU will continue to check whether the SOH (State of Health) of the target liquid circuit subsystem is greater than the preset threshold. If the SOH of the target liquid circuit subsystem is greater than the preset threshold, it means that the target liquid circuit subsystem is in a healthy state and operating well.

[0138] When the target BCU determines that the SOH of the target liquid circuit subsystem is greater than the preset threshold, the target BCU will continue to determine whether the temperature of the positive and negative electrode storage tanks in the target liquid circuit subsystem is within the preset range. If the target BCU determines that the temperature of the positive and negative electrode storage tanks is within the preset range, it means that the stack in the target liquid circuit subsystem can normally convert the chemical energy of the electrolyte into electrical energy.

[0139] If the temperature of the positive electrode storage tank is not within the preset range, it indicates that the target liquid circuit subsystem cannot properly convert the chemical energy of the electrolyte into electrical energy. In this case, the target BCU will activate the refrigerator in the positive electrode liquid circuit or the heating cable covering the positive electrode storage tank to cool or heat the tank, thereby maintaining the temperature of the positive electrode storage tank within the preset range. If the temperature of the negative electrode storage tank is not within the preset range, the target BCU will activate the refrigerator in the negative electrode liquid circuit or the heating cable covering the negative electrode storage tank to cool or heat the tank, thereby maintaining the temperature of the negative electrode storage tank within the preset range.

[0140] In summary, when the main switch of the BAU is closed, if the target BCU determines that the total load pressure, positive and negative voltage to ground, output voltage, open circuit voltage, liquid pressure signal and fire alarm signal of the target liquid circuit subsystem are all normal, and the SOH of the target liquid circuit subsystem is greater than the preset threshold, and the temperature of the positive and negative liquid storage tanks in the target liquid circuit subsystem is within the preset range, then the target liquid circuit subsystem is in normal operating condition.

[0141] It should be noted that if the target BCU detects an abnormality in any of the above parameters of the target fluid circuit subsystem during the detection process, it will also provide corresponding warning information, so that the staff can deal with the abnormal phenomena in the target fluid circuit subsystem in a timely manner, thereby ensuring the overall reliability of the target fluid circuit subsystem during operation.

[0142] Obviously, the technical solution provided in this embodiment can accurately determine whether the target liquid circuit subsystem is in normal operating condition.

[0143] Please see Figure 7 , Figure 7 This is a flowchart illustrating the control of a target fluid circuit subsystem according to an embodiment of the present invention. In a preferred embodiment, the above steps, including controlling the operating state of the target fluid circuit subsystem to respond to target commands, include:

[0144] Step S301: Control the positive return valve and negative return valve in the target liquid circuit subsystem to open, and control the positive pump and negative pump in the target liquid circuit subsystem to start running;

[0145] Step S302: Control the closure of the positive and negative contactors in the target fluid circuit subsystem;

[0146] Step S303: Parse the target instruction to obtain target parsing data;

[0147] Step S304: Control the operating speed of the positive and negative pumps in the target liquid circuit subsystem according to the target analysis data, so as to control the output current of the target liquid circuit subsystem.

[0148] When the target BCU controls the operating status of the target liquid circuit subsystem, it first opens the positive and negative return valves in the target liquid circuit subsystem and controls the positive and negative pumps in the target liquid circuit subsystem to start running, so that the electrolyte in the positive and negative liquid circuits in the target liquid circuit subsystem can circulate.

[0149] Afterwards, the target BCU will control the positive and negative contactors in the target fluid circuit subsystem to close. In this state, the string fluid energy storage system is actually connected to the grid and the grid connection operation is completed.

[0150] After the string flow energy storage system completes grid connection, the target BCU will parse the target command to obtain target parsing data, and control the operating speed of the positive and negative pumps in the target fluid circuit subsystem based on the target parsing data, thereby achieving the purpose of controlling the output current of the target fluid circuit subsystem.

[0151] The target BCU parses the target commands to obtain target parsed data. This parsed data reveals whether the EMS requires the target liquid circuit subsystem to perform a charging or discharging operation, and specifies the corresponding charging and discharging parameters. After parsing this data, the target BCU controls the operating speeds of the positive and negative pumps in the target liquid circuit subsystem. By controlling the operating speeds of the positive and negative pumps, the reaction rate of the electrolyte in the fuel cell stack can be controlled, thereby achieving the goal of controlling the output current of the target liquid circuit subsystem.

[0152] Obviously, the technical solution provided in this embodiment enables the target liquid circuit subsystem to respond to target commands.

[0153] As a preferred embodiment, the above steps, including controlling the operating speeds of the positive and negative pumps in the target liquid circuit subsystem based on target analysis data to control the output current of the target liquid circuit subsystem, include:

[0154] The flow rate of the electrolyte and the output current of the target liquid circuit subsystem were detected respectively.

[0155] Based on the target analysis data, and according to the flow rate of the electrolyte in the target liquid circuit subsystem and the output current of the target liquid circuit subsystem, the operating speed of the positive and negative pumps in the target liquid circuit subsystem is adjusted.

[0156] In this embodiment, when controlling the output current of the target liquid circuit subsystem, the target BCU also utilizes the positive and negative inlet flow sensors respectively installed in the positive and negative liquid circuits to detect the flow rate of the electrolyte in the target liquid circuit subsystem. Simultaneously, the target BCU also utilizes Hall effect sensors installed in the electrical circuits of the target liquid circuit subsystem to detect the output current of the target liquid circuit subsystem.

[0157] Understandably, the electrolyte flow rate and output current of the target liquid circuit subsystem characterize its actual operating parameters, while the target analytical data characterizes its desired operating parameters. Since there may be some differences between the desired and actual operating parameters of the target liquid circuit subsystem, using the target analytical data as a benchmark and adjusting the operating speeds of the positive and negative pumps based on the electrolyte flow rate and output current allows the actual operating parameters to gradually reach the desired operating parameters.

[0158] Clearly, the technical solution provided in this embodiment allows for more precise control of the operating status of the target liquid circuit subsystem.

[0159] Please continue reading Figure 7 The above control methods also include:

[0160] Step S305: During the process of controlling the output current of the target liquid circuit subsystem, the voltage of the target single electrode is detected by the target BMU; the target single electrode is any single electrode in the target stack; the target stack is any stack in the target liquid circuit subsystem; the target BMU is the BMU connected to the target single electrode.

[0161] Step S306: When the target command is a discharge command, determine whether the voltage of the target single electrode is lower than the first preset threshold; if yes, proceed to step S307; if no, proceed to step 304.

[0162] Step S307: Control the target single electrode to stop discharging, and control the positive and negative pumps in the target liquid circuit subsystem to stop running;

[0163] Step S308: When the target instruction is a charging instruction, determine whether the voltage of the target single electrode is higher than the second preset threshold; if yes, proceed to step S309; ​​if no, proceed to step S304.

[0164] Step S309: Control the target single electrode to stop charging, and control the positive and negative pumps in the target liquid circuit subsystem to stop running.

[0165] During the process of controlling the output current of the target liquid circuit subsystem, the target BCU will also send instructions to the target BMU (Battery Management Unit) and instruct the target BMU to detect the output voltage of the target single electrode.

[0166] It should be noted that any electrode stack in the target liquid circuit subsystem is composed of multiple individual electrodes, and each individual electrode in a stack is connected to a corresponding BMU. The function of the BMU is to detect the operating parameters of the individual electrodes, such as voltage, current, and temperature.

[0167] If the target command is a discharge command, the target BCU will determine whether the voltage of the target individual electrode is lower than a first preset threshold. If the voltage of the target individual electrode is lower than the first preset threshold, it means that the voltage of the target individual electrode is too low and cannot continue to discharge. At this time, the target BCU will control the positive and negative pumps in the target liquid circuit subsystem to stop operating. If the voltage of the target individual electrode is higher than the first preset threshold, it means that the target individual electrode can continue to discharge. In this case, it is only necessary to continue to execute step S304.

[0168] If the target command is a charging command, the target BCU will determine whether the voltage of the target individual electrode is higher than a second preset threshold. If the voltage of the target individual electrode is higher than the second preset threshold, it means that the target individual electrode is close to saturation and cannot continue charging. In this case, the target BCU needs to control the target individual electrode to stop charging and control the positive and negative pumps in the target liquid circuit subsystem to stop operating. If the voltage of the target individual electrode is lower than the second preset threshold, it means that the target individual electrode can continue charging, and in this case, only step S304 needs to be executed.

[0169] It should be noted that when the positive and negative pumps in the target fluid circuit subsystem are stopped by the target BCU, the PCS will operate at reduced power. After a period of time, the target BCU will disconnect the positive and negative contactors in the target fluid circuit subsystem, thus removing the target fluid circuit subsystem from the string flow energy storage system.

[0170] Obviously, the technical solution provided in this embodiment can promptly disconnect the target liquid circuit subsystem from the string flow energy storage system when a failure occurs, without affecting the operation of other liquid circuit subsystems in the string flow energy storage system.

[0171] In a preferred embodiment, the above control method further includes:

[0172] The target BMU detects the current and temperature data of the target single electrode and inputs the current and temperature data of the target single electrode into a preset model to determine whether the target single electrode has a fault.

[0173] The creation process of the preset model includes:

[0174] The current and temperature data of the target single electrode under normal and fault conditions are obtained in advance, and a preset model is created based on the current and temperature data of the target single electrode under normal and fault conditions using artificial intelligence algorithms.

[0175] It is understandable that the current and temperature data of the target single electrode are different in normal operation and fault conditions. Therefore, based on this characteristic of the current and temperature data of the target single electrode in normal operation and fault conditions, a preset model can be created based on artificial intelligence algorithms, and the preset model can be used to determine whether the target single electrode is in normal operation.

[0176] Specifically, when creating a preset model, it is necessary to obtain the current and temperature data of the target single electrode under normal operation and fault conditions in advance; then, based on artificial intelligence algorithms, the current and temperature data of the target single electrode under normal operation and fault conditions are trained to create the preset model.

[0177] Once the preset model is created, the target BCU can send commands to the target BMU and use the target BMU to detect the current and temperature data of the target individual electrode. After the target BCU obtains the current and temperature data of the target individual electrode, it inputs the data into the preset model. Based on the output of the preset model, it can determine whether the target individual electrode has malfunctioned.

[0178] When a fault is detected in the target individual electrode, the target BCU can disconnect the positive and negative contactors in the target liquid circuit subsystem, thereby achieving the purpose of protecting the target liquid circuit subsystem.

[0179] Obviously, the technical solution provided in this embodiment can accurately determine whether the target single electrode is faulty.

[0180] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0181] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0182] The present invention provides a detailed description of a string flow energy storage system and its control method. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, those skilled in the art will recognize that there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A string flow energy storage system, characterized in that, include: The liquid circuit subsystem is composed of The system consists of several fuel cells connected in series, which are used to deliver electrolyte to each fuel cell through liquid pipelines so that each fuel cell can convert the chemical energy of the electrolyte into electrical energy. ; The BCU is connected to the liquid circuit subsystem and is used to acquire the operating data of the liquid circuit subsystem and regulate the operating status of the liquid circuit subsystem. PCS, connected to the BCU, is used to control the energy output by the liquid circuit subsystem; BAU is connected to multiple PCS and multiple BCUs, and is used to receive data reported by each PCS and each BCU, and to control the operating status of each liquid circuit subsystem according to the instructions issued by EMS. The EMS is connected to the BAU and is used to control each BCU, each PCS, the BAU and each liquid circuit subsystem according to user instructions and data reported by the BAU.

2. The string flow energy storage system according to claim 1, characterized in that, The fluid circuit subsystem includes: A series of interconnected components including a fuel cell stack, a positive contactor, a negative contactor, a positive electrode liquid storage tank, a negative electrode liquid storage tank, a positive electrode pump, a negative electrode pump, a positive electrode valve module, a negative electrode valve module, a positive electrode liquid circuit detection module, a negative electrode liquid circuit detection module, a positive electrode constant temperature module, and a negative electrode constant temperature module. in, The positive output terminal of each series-connected fuel cell stack is connected to the first terminal of the positive contactor, and the second terminal of the positive contactor is connected to the PCS. The negative output terminal of each series-connected fuel cell stack is connected to the first terminal of the negative contactor, and the second terminal of the negative contactor is connected to the PCS. In the series-connected stacks, the first The second positive electrode liquid flow port of the fuel cell stack is connected to the first The first positive electrode liquid flow port of the stack is connected, the second The second negative electrode liquid flow port of the fuel cell stack is connected to the first The first negative electrode liquid flow port of each fuel cell stack is connected. The first positive electrode liquid flow port of the first fuel cell stack connects to the first positive electrode through the positive electrode liquid path detection module, the positive electrode pump, the positive electrode constant temperature module, and the positive electrode valve module. The second positive electrode liquid flow port of the first fuel cell stack is connected; the first negative electrode liquid flow port of the first fuel cell stack is connected to the second positive electrode liquid flow port through the negative electrode liquid path detection module, the negative electrode pump, the negative electrode constant temperature module, and the negative electrode valve module. The second negative electrode liquid flow port of each fuel cell stack is connected; The positive electrode liquid path detection module is used to detect inflow and outflow in the positive electrode liquid path circuit. The electrolyte parameters of the interconnected fuel cell stacks are detected; the negative electrode liquid path detection module is used to detect the inflow and outflow in the negative electrode liquid path circuit. The electrolyte parameters of the interconnected battery stacks are detected; the positive electrode constant temperature module and the negative electrode constant temperature module are used to keep the positive electrode storage tank and the negative electrode storage tank warm or cool them, so that the temperature of the positive electrode storage tank and the negative electrode storage tank is kept within a preset range; the positive electrode valve module and the negative electrode valve module are used to control the electrolyte flowing through the positive electrode pump and the negative electrode pump, respectively.

3. The string flow energy storage system according to claim 2, characterized in that, The positive electrode liquid circuit detection module includes: A positive electrode inlet temperature sensor is used to detect the temperature of the liquid flowing into the positive electrode circuit. The temperature of the electrolyte in the series-connected fuel cells is monitored. Positive electrode inlet pressure sensor; used to monitor the inflow of liquid into the positive electrode liquid circuit. The pressure of the electrolyte in the series-connected fuel cells is monitored. Positive electrode inlet flow sensor; used to detect the inflow into the positive electrode liquid circuit. The flow rate of electrolyte in a series-connected stack is detected. Positive electrode return temperature sensor; used to monitor the temperature of the outflowing liquid in the positive electrode liquid circuit. The temperature of the electrolyte in the series-connected fuel cells is monitored. Accordingly, the negative electrode liquid circuit detection module includes: A negative electrode inlet temperature sensor is used to detect the temperature of the liquid flowing into the negative electrode circuit. The temperature of the electrolyte in the series-connected fuel cells is monitored. Negative electrode inlet pressure sensor; used to monitor the inflow of liquid into the negative electrode liquid circuit. The pressure of the electrolyte in the series-connected fuel cells is monitored. Negative electrode inlet flow sensor; used to measure the flow rate of liquid entering the negative electrode in the negative electrode liquid circuit. The flow rate of electrolyte in a series-connected stack is detected. Negative electrode return temperature sensor; used to monitor the temperature of the outflowing liquid in the negative electrode liquid circuit. The temperature of the electrolyte in the series-connected fuel cell stacks was measured.

4. The string flow energy storage system according to claim 2, characterized in that, The positive electrode valve module includes: a positive electrode return valve and a positive electrode mixing valve; the negative electrode valve module includes: a negative electrode return valve and a negative electrode mixing valve. The positive electrode return valve is connected to the positive electrode storage tank and the first... Between the second positive electrode liquid flow port of the fuel cell stack; the negative electrode return valve is connected between the negative electrode liquid storage tank and the first... Between the second negative electrode liquid flow ports of the fuel cell stacks; the positive electrode mixing valve is connected between the positive electrode return valve and the negative electrode return valve; the negative electrode mixing valve is connected between the negative electrode return valve and the positive electrode return valve.

5. A control method for a string flow energy storage system, characterized in that, A target BCU applied to a string flow energy storage system according to any one of claims 1 to 4; the target BCU is any one of a plurality of BCUs, including: Monitor BAU; When the BAU receives the target instruction issued by the EMS, it determines whether the target fluid circuit subsystem is in normal operating condition; the target fluid circuit subsystem is the fluid circuit subsystem connected to the target BCU. If so, the operating state of the target liquid circuit subsystem is controlled to respond to the target command.

6. The control method for a string flow energy storage system according to claim 5, characterized in that, The determination of whether the target liquid circuit subsystem is in normal operating condition includes: When the main switch of the BAU is closed, it is determined whether the total load pressure of the target fluid circuit subsystem is normal. If so, determine whether the positive and negative terminal voltages to ground, output voltage, open circuit voltage, liquid pressure signal, and fire alarm signal of the target liquid circuit subsystem are all normal; If so, determine whether the SOH of the target liquid circuit subsystem is greater than a preset threshold; If so, determine whether the temperatures of the positive electrode storage tank and the negative electrode storage tank in the target liquid circuit subsystem are within the preset range; If so, the target liquid circuit subsystem is determined to be in normal operating condition.

7. The control method for a string flow energy storage system according to claim 5, characterized in that, Controlling the operating state of the target fluid circuit subsystem to respond to the target command includes: The positive return valve and negative return valve in the target liquid circuit subsystem are opened, and the positive pump and negative pump in the target liquid circuit subsystem are started and run. Control the closure of the positive and negative contactors in the target liquid circuit subsystem; The target instruction is parsed to obtain target parsing data, and the operating speed of the positive and negative pumps in the target liquid circuit subsystem is controlled according to the target parsing data, so as to control the output current of the target liquid circuit subsystem.

8. The control method for a string flow energy storage system according to claim 7, characterized in that, The step of controlling the operating speed of the positive and negative pumps in the target liquid circuit subsystem based on the target analysis data, in order to control the output current of the target liquid circuit subsystem, includes: The flow rate of the electrolyte in the target liquid circuit subsystem and the output current of the target liquid circuit subsystem are detected respectively. Based on the target analysis data, and according to the flow rate of the electrolyte in the target liquid circuit subsystem and the output current of the target liquid circuit subsystem, the operating speed of the positive and negative pumps in the target liquid circuit subsystem is adjusted.

9. The control method for a string flow energy storage system according to claim 7, characterized in that, Also includes: During the process of controlling the output current of the target liquid circuit subsystem, the voltage of the target individual electrode is detected using the target BMU; The target single electrode is any single electrode in the target fuel cell stack; The target fuel cell stack is any one of the fuel cell stacks in the target liquid circuit subsystem; the target BMU is the BMU connected to the target single electrode. When the target command is a discharge command, it is determined whether the voltage of the target single electrode is lower than a first preset threshold. If so, then control the target single electrode to stop discharging, and control the positive and negative pumps in the target liquid circuit subsystem to stop operating; If not, continue with the step of controlling the operating speed of the positive and negative pumps in the target liquid circuit subsystem based on the target analysis data, so as to control the output current of the target liquid circuit subsystem; When the target instruction is a charging instruction, it is determined whether the voltage of the target single electrode is higher than the second preset threshold. If so, then control the target single electrode to stop charging, and control the positive and negative pumps in the target liquid circuit subsystem to stop running; If not, continue with the step of controlling the operating speed of the positive and negative pumps in the target liquid circuit subsystem based on the target analysis data, so as to control the output current of the target liquid circuit subsystem.

10. The control method for a string flow energy storage system according to claim 9, characterized in that, Also includes: The target BMU detects the current and temperature data of the target single electrode, and inputs the current and temperature data of the target single electrode into a preset model to determine whether the target single electrode has a fault. The creation process of the preset model includes: The current and temperature data corresponding to the target single electrode under normal operation and fault conditions are obtained in advance, and the preset model is created based on the current and temperature data corresponding to the target single electrode under normal operation and fault conditions using artificial intelligence algorithms.

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