Dynamic energy storage liquid flow circulation control system and method

Abstract

The invention discloses a dynamic energy storage liquid flow circulation control system and method. The dynamic energy storage liquid flow circulation control system comprises an inverter, a control system, a liquid flow energy storage system, a liquid flow circulation system, a connecting pipeline and a valve set. The liquid flow energy storage system consists of a plurality of single battery systems and a public battery system, and is provided with an electric pile unit, an electrolyte storage tank and a circulating pump; the liquid flow circulation system comprises a lifting pump, a set of high-position storage tank and a set of low-position storage tank, liquid flow circulation is achieved through gravitational potential energy and the lifting pump, the control system conducts coordinated control on a circulation pump, the lifting pump and a valve set, and liquid flow circulation control of a conventional operation stage and an instruction response stage is achieved. Direct current generated by electrochemical reaction of the galvanic pile unit is converted into alternating current through the inverter to be supplied to a power grid for use, the state of the system is monitored in real time through the voltage sensor, the current sensor and the hydraulic sensor, and efficient and stable operation is ensured. Through the design, electric energy and chemical energy are efficiently converted, continuous charging and discharging are supported, and the overall efficiency and flexibility of the system are improved.

Description

Technical Field

[0001] The invention relates to the field of electrolyte energy storage, and mainly to a dynamic energy storage liquid flow circulation control system and method. Background Art

[0002] With the continuous growth of global energy demand and the rapid development of new energy technologies, the frequency and peak regulation of power grids has become increasingly important. Power grid frequency and peak regulation refers to maintaining the balance between power grid frequency and power supply by adjusting power generation and load in the power system to ensure the stable operation of the power system. As a new type of energy storage technology, liquid flow energy storage consists of a battery stack unit, electrolyte, electrolyte storage and supply unit, and management and control unit. It is a high-performance battery that separates positive and negative electrolytes and circulates them separately. It has the technical advantages of high capacity, intrinsic safety, large capacity, long life, and high residual value.

[0003] At present, the response time for energy storage participating in system frequency modulation is not less than 0.5S. If liquid flow energy storage batteries are to meet the response time required for frequency modulation, it is necessary to ensure that the battery stack unit is always full of electrolyte, and the electrolyte state of charge (SOC) needs to be as consistent as possible with the electrolyte in the storage tank. When the current liquid flow energy storage solutions participate in frequency modulation, either the response rate cannot keep up with the requirements, or there are problems such as high equipment failure rate and large power loss.

[0004] For example, CN204348822U "A Liquid Flow Battery Device" discloses "A liquid flow battery device, including a liquid flow battery or a liquid flow battery group, a positive electrode high-position electrolyte storage tank, a positive electrode low-position electrolyte storage tank, a negative electrode high-position electrolyte storage tank and a negative electrode low-position electrolyte storage tank, the positive electrode high-position electrolyte storage tank is connected to the positive electrode upper port of the liquid flow battery or the liquid flow battery group through a pipeline, the positive electrode low-position electrolyte storage tank is connected to the positive electrode lower port of the liquid flow battery or the liquid flow battery group through a pipeline; the negative electrode high-position electrolyte storage tank is connected to the liquid electrode through a pipeline. The negative electrode upper port of the flow battery or liquid flow battery group is connected, and the negative electrode low-level electrolyte storage tank is connected to the negative electrode lower port of the flow battery or liquid flow battery group through a pipeline; part of the pump work consumed in the charging process is converted into potential energy and stored. However, the method relies on the pump to circulate the electrolyte, resulting in low efficiency in the conversion and storage of potential energy during the charging process, and fails to fully utilize the advantages of gravitational potential energy; in addition, multiple high-level and low-level storage tanks and complex pipeline designs do not realize the circulation mechanism of the electrolyte, affecting the energy utilization efficiency and system stability. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present application provides a dynamic energy storage liquid flow circulation control method and method.

[0006] The technical solution of this application is as follows:

[0007] The dynamic energy storage liquid flow circulation control system includes an inverter, a control system, a liquid flow energy storage system, a liquid flow circulation system, connecting pipes and a valve group. The liquid flow energy storage system includes multiple single battery systems and a common battery system. The single battery system and the common battery system both include a battery stack unit, an anode electrolyte storage tank, a cathode electrolyte storage tank and a circulation pump; the liquid flow circulation system includes a lifting pump, a low-position anode electrolyte storage tank, a low-position cathode electrolyte storage tank, a high-position anode electrolyte storage tank and a high-position cathode electrolyte storage tank. The valve group includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve and a seventh valve, wherein:

[0008] The stack unit is connected to the anode electrolyte storage tank and the cathode electrolyte storage tank through a connecting pipe to form an electrolyte circulation loop, and the circulation loop uses a circulation pump to circulate the electrolyte; a sixth valve is provided at the positive and negative electrode outlets of the stack unit, and the stack unit is respectively connected to the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank through the sixth valve and the connecting pipe;

[0009] A seventh valve is respectively provided at the outlet of the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank, and the seventh valve is used to control the electrolyte to flow to the lifting pump. The low-position anode electrolyte storage tank is connected to the high-position anode electrolyte storage tank through the seventh valve, the lifting pump and the connecting pipe, and the low-position cathode electrolyte storage tank is connected to the high-position cathode electrolyte storage tank through the seventh valve, the lifting pump and the connecting pipe;

[0010] A fourth valve is provided at the outlet of the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank, which are connected to the inlet of the stack unit through the fourth valve and the connecting pipe, and the fourth valve is used to control the electrolyte to flow to the inlet of the stack unit;

[0011] The control system coordinates and controls the circulation pump, the lifting pump and the valve group to achieve liquid flow circulation control in the normal operation stage and the command response stage.

[0012] As a preferred embodiment of the present invention, the circulation loop utilizes a circulation pump to circulate the electrolyte specifically as follows:

[0013] A circulation pump is provided at the outlet of the anode electrolyte storage tank and the cathode electrolyte storage tank, and a first valve is provided at the outlet of the circulation pump. Before starting the circulation pump, the first valve is closed first, and the pressure is held until a preset outlet pressure value is reached, and then the circulation pump is started; a second valve is provided at the inlet of the anode electrolyte storage tank and the cathode electrolyte storage tank. The first valve and the second valve are opened to transport the electrolyte from the anode electrolyte storage tank and the cathode electrolyte storage tank to the stack unit, and the electrolyte after participating in the electrochemical reaction is returned to the anode electrolyte storage tank and the cathode electrolyte storage tank for storage.

[0014] As a preferred embodiment of the present invention, a third valve is respectively provided at the outlet of the anode electrolyte storage tank and the cathode electrolyte storage tank of the common battery system, and the anode electrolyte storage tank of the common battery system is connected to the high-position anode electrolyte storage tank via the third valve, a lifting pump and a connecting pipe, and the cathode electrolyte storage tank of the common battery system is connected to the high-position cathode electrolyte storage tank via the third valve, a lifting pump and a connecting pipe.

[0015] As a preferred embodiment of the present invention, the lifting pump is used to lift the electrolyte in the low-positioned anode electrolyte storage tank and the anode electrolyte storage tank of the common battery system to the high-positioned anode electrolyte storage tank, and to lift the electrolyte in the low-positioned cathode electrolyte storage tank and the cathode electrolyte storage tank of the common battery system to the high-positioned cathode electrolyte storage tank.

[0016] As a preferred embodiment of the present invention, the normal operation stage includes a charging operation and a self-balancing operation, wherein the charging operation specifically charges the single battery system; and the self-balancing operation specifically includes:

[0017] The control system closes the first valve and the second valve corresponding to each single battery system, opens the third valve, and starts the lifting pump, so that the electrolyte in the anode electrolyte storage tank of the common battery system is lifted to the high-position anode electrolyte storage tank for connection, and the electrolyte in the cathode electrolyte storage tank of the common battery system is lifted to the high-position cathode electrolyte storage tank;

[0018] When the high-position anode electrolyte storage tank connection and the electrolyte in the high-position cathode electrolyte storage tank are raised to a preset height, the fourth valve and the fifth valve and the sixth valve corresponding to the liquid flow energy storage system are opened, and the electrolyte in the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank flows into the battery stack unit through the connecting pipe using gravitational potential energy, and flows from the battery stack unit into the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank;

[0019] When the corresponding liquid levels of the electrolyte in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank reach the preset height, the seventh valve is opened, and the electrolyte after the charging reaction in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank is lifted to the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank by the lifting pump.

[0020] As a preferred embodiment of the present invention, the instruction response stage is specifically as follows:

[0021] When the control system receives frequency modulation, peak modulation and discharge instructions, the first valve and the second valve corresponding to each single battery system are opened, and the fifth valve and the sixth valve corresponding to each single battery system are closed, and each single battery system performs self-circulation;

[0022] The third valve and the sixth valve corresponding to the common battery system are closed, and the second valve corresponding to the common battery system is opened, so that the electrolyte in the high-positioned anode electrolyte storage tank and the high-positioned cathode electrolyte storage tank flows back to the anode electrolyte storage tank and the cathode electrolyte storage tank of the common battery system;

[0023] When the electrolyte in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank in the liquid circulation operation is emptied, close the lifting pump and the seventh valve; when the electrolyte reflux in the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank is completed, open the first valve corresponding to the common battery system, close the fourth valve and the fifth valve corresponding to the common battery system, and the common battery system performs self-circulation.

[0024] As a preferred embodiment of the present invention, the inverter is used to convert the direct current generated during the discharge of the battery stack unit into alternating current and provide it to the power grid for use.

[0025] As a preferred embodiment of the present invention, the dynamic energy storage liquid flow circulation control system further includes a voltage sensor, a current sensor and a hydraulic pressure sensor, wherein:

[0026] The voltage sensor is installed on the battery stack unit. When the single battery system is charged, the control system detects the charge state of each single battery system in real time through the voltage sensor, and adjusts the single battery system with the goal of making the charge state of each single battery system consistent until charging is completed;

[0027] The current sensor is installed on the inlet and outlet connecting pipes of the circulation pump and the lifting pump to monitor the flow current of the electrolyte; the liquid level sensor is installed in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank to monitor the liquid level change of the electrolyte in real time.

[0028] The present invention also provides a dynamic energy storage liquid flow circulation control method, the method comprising:

[0029] The control system receives the charging instruction and charges the single battery system. When the single battery system is charged, the control system detects the charge state of each single battery system in real time through the voltage sensor, and adjusts the single battery system with the goal of making the charge state of each single battery system consistent until the charging is completed;

[0030] After charging, the control system closes the first valve and the second valve corresponding to each single battery system, opens the third valve, and starts the lifting pump, so that the electrolyte in the anode electrolyte storage tank of the common battery system is lifted to the high-position anode electrolyte storage tank for connection, and the electrolyte in the cathode electrolyte storage tank of the common battery system is lifted to the high-position cathode electrolyte storage tank;

[0031] When the high-position anode electrolyte storage tank is connected and the electrolyte in the high-position cathode electrolyte storage tank is lifted to a preset height, the fourth valve and the fifth valve and the sixth valve corresponding to the liquid flow energy storage system are opened, and the electrolyte in the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank flows into the battery stack unit through the connecting pipe using gravitational potential energy, and flows from the battery stack unit into the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank; used to convert the direct current generated during the discharge of the battery stack unit into alternating current and provide it to the power grid for use. When the control system receives frequency modulation, peak regulation and discharge instructions, the first valve and the second valve corresponding to each single battery system are opened, and the fifth valve and the sixth valve corresponding to each single battery system are closed, and each single battery system performs self-circulation;

[0032] The third valve and the sixth valve corresponding to the common battery system are closed, and the second valve corresponding to the common battery system is opened, so that the electrolyte in the high-positioned anode electrolyte storage tank and the high-positioned cathode electrolyte storage tank flows back to the anode electrolyte storage tank and the cathode electrolyte storage tank of the common battery system;

[0033] When the electrolyte in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank in the liquid circulation operation is emptied, the lifting pump and the seventh valve are closed; when the electrolyte in the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank is refluxed, the first valve corresponding to the common battery system is opened, the fourth valve and the fifth valve corresponding to the common battery system are closed, and the common battery system performs self-circulation;

[0034] The inverter converts the DC power generated during the discharge of the battery stack unit into AC power and supplies it to the grid until the command is completed;

[0035] As a preferred embodiment of the present invention, the method further includes monitoring the flow current and liquid level change of the electrolyte by a current sensor and a liquid level sensor respectively during the circulation of the electrolyte, so as to realize dynamic control of the liquid flow energy storage system.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1) The present invention provides a dynamic energy storage liquid flow circulation control system and method. The high-level electrolyte storage tank stores the electrolyte after charging, and uses the gravitational potential energy to press it into the battery stack unit to ensure that the battery stack unit is always full of fresh electrolyte; the electrolyte after the reaction flows back to the low-level electrolyte storage tank, and then lifted to the high-level storage tank, forming a closed-loop circulation; the above circulation process not only ensures the continuous supply of electrolyte, but also ensures the renewal of electrolyte, thereby improving the operating efficiency and stability of the public battery system;

[0038] 2) The present invention provides a dynamic energy storage liquid flow circulation control system and method. Since the battery stack unit is always full of electrolyte, the energy storage system can be quickly started when there is energy demand. At the same time, the valve group is controlled to open and the circulation pump of each single battery system is started. After the circulation pump reaches the preset outlet pressure value, the system circulates by itself. This process shortens the response time of the energy storage system, meets the response time requirements of the power grid for energy storage participating in system frequency modulation, and improves the stability and reliability of the power system.

[0039] 3) The present invention provides a dynamic energy storage liquid flow circulation control system and method. By setting high-level and low-level storage tanks and circulating the electrolyte, the circulation pumps of each battery system are turned off when there is no energy demand, thereby reducing power loss and operating time, reducing failure rate, extending the service life of the equipment, and reducing maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a system principle diagram of an embodiment of the present invention;

[0041] In the figure:

[0042] 1- stack unit; 2- anode electrolyte storage tank; 3- cathode electrolyte storage tank; 4- circulation pump; 5- lifting pump; 6- low-position anode electrolyte storage tank; 7- low-position cathode electrolyte storage tank; 8- high-position anode electrolyte storage tank; 9- high-position cathode electrolyte storage tank; 10- first valve; 11- second valve; 12- third valve; 13- fourth valve; 14- fifth valve; 15- sixth valve; 16- seventh valve; 17- control system; 18- inverter. DETAILED DESCRIPTION

[0043] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0044] The present invention provides the following technical solution: a dynamic energy storage liquid flow circulation control system and method.

[0045] Example 1

[0046] like Figure 1 As shown, this embodiment provides a dynamic energy storage liquid flow circulation control system, which includes an inverter, a control system, a liquid flow energy storage system, a liquid flow circulation system, a connecting pipeline and a valve group, and the valve group includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve and a seventh valve, wherein:

[0047] S1. The liquid flow energy storage system includes a plurality of single cell systems and a common battery system, wherein the single cell system and the common battery system both include a battery stack unit, an anode electrolyte storage tank, a cathode electrolyte storage tank and a circulation pump;

[0048] S11, the stack unit includes a positive electrode and a negative electrode, which are used to perform an oxidation-reduction electrochemical reaction to realize the charging and discharging process. The stack units in the liquid flow energy storage system are connected through a fifth valve and a connecting pipe. Further:

[0049] S111, the stack units of each single cell system share the flow path of the electrolyte through the fifth valve, which is convenient for unified management and control of the circulation of the electrolyte, and if the user needs to operate the single cell system independently or in combination, this implementation flexibly selects which single cell systems to connect to the main circulation loop or isolates certain single cell systems from the main circulation loop by setting the fifth valve;

[0050] S112, the public battery system shares electrolyte resources with multiple single battery systems through the fifth valve, ensuring that the electrolyte can be efficiently distributed and used when the demand for electrolyte is large; when the battery stack unit in the public battery system needs to work in coordination with other single battery systems, for example, the flow of electrolyte needs to be uniformly controlled during the discharge or charging operation, this embodiment sets the fifth valve to enable the public battery system to seamlessly connect to the entire system to achieve coordinated work;

[0051] S12. The negative electrode and the positive electrode of the stack unit are connected to the anolyte storage tank and the cathode electrolyte storage tank respectively through connecting pipes. The anolyte storage tank is used to store the anolyte and cooperates with the stack unit to realize the mutual conversion of electrical energy and chemical energy; the cathode electrolyte storage tank is used to store the cathode electrolyte and cooperates with the stack unit to realize the mutual conversion of electrical energy and chemical energy; the stack unit and the anolyte storage tank and the cathode electrolyte storage tank form a circulation loop of the electrolyte, and the circulation loop uses a circulation pump to circulate the electrolyte, specifically:

[0052] A circulation pump is provided at the outlet of the anolyte storage tank and the cathode electrolyte storage tank. A first valve is provided at the outlet of the circulation pump. Before starting the circulation pump, the first valve is closed first and the pressure is held until a preset outlet pressure value is reached to ensure that the electrolyte has sufficient pressure during the circulation process to ensure that the reaction in the stack unit can proceed smoothly. At this time, the circulation pump is started; a second valve is provided at the inlet of the anolyte storage tank and the cathode electrolyte storage tank. The first valve and the second valve are gradually opened to transport the electrolyte from the anolyte storage tank and the cathode electrolyte storage tank to the stack unit, and the electrolyte after participating in the electrochemical reaction is returned to the anolyte storage tank and the cathode electrolyte storage tank for storage, so as to realize the self-circulation of the liquid flow energy storage system;

[0053] S2, the liquid circulation system includes a lift pump, a low-positioned anode electrolyte storage tank, a low-positioned cathode electrolyte storage tank, a high-positioned anode electrolyte storage tank and a high-positioned cathode electrolyte storage tank;

[0054] S21. A sixth valve is provided at the positive and negative electrode outlets of the stack unit in the liquid flow energy storage system. The outlet of the stack unit is respectively connected to the inlets of the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank through the sixth valve and the connecting pipe. Specifically, the negative electrode of the stack unit is connected to the low-position anode electrolyte storage tank through the sixth valve and the connecting pipe, and the positive electrode of the stack unit is connected to the low-position cathode electrolyte storage tank through the sixth valve and the connecting pipe. The low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank are used to collect the electrolyte after the charging reaction flowing out of the stack unit;

[0055] Preferably, a third valve is also provided at the outlet of the anode electrolyte storage tank and the cathode electrolyte storage tank of the common battery system, respectively. The anode electrolyte storage tank of the common battery system is connected to the high-position anode electrolyte storage tank through the third valve, a lifting pump and a connecting pipe, and the cathode electrolyte storage tank of the common battery system is connected to the high-position cathode electrolyte storage tank through the third valve, a lifting pump and a connecting pipe.

[0056] A seventh valve is respectively provided at the outlet of the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank, and the seventh valve is used to control the electrolyte to flow to the lifting pump. The low-position anode electrolyte storage tank is connected to the high-position anode electrolyte storage tank through the seventh valve, the lifting pump and the connecting pipe, and the low-position cathode electrolyte storage tank is connected to the high-position cathode electrolyte storage tank through the seventh valve, the lifting pump and the connecting pipe, forming a vertical circulation loop of the electrolyte to realize the vertical circulation of the electrolyte;

[0057] It is worth noting that, in order to improve work efficiency, the anode electrolyte storage tank of the common battery system and the low-position anode electrolyte storage tank share a lift pump, and the cathode electrolyte storage tank of the common battery system and the low-position cathode electrolyte storage tank share a lift pump. This embodiment reduces the complexity of the system through the design of a shared lift pump, and improves the work efficiency of the system by sharing resources;

[0058] The above-mentioned lifting pump is used to lift the electrolyte in the low-positioned anode electrolyte storage tank and the anode electrolyte storage tank of the common battery system to the high-positioned anode electrolyte storage tank, and to lift the electrolyte in the low-positioned cathode electrolyte storage tank and the cathode electrolyte storage tank of the common battery system to the high-positioned cathode electrolyte storage tank, so as to facilitate the subsequent circulation and utilization of the electrolyte; a fourth valve is provided at the outlet of the high-positioned anode electrolyte storage tank and the high-positioned cathode electrolyte storage tank, which is connected to the inlet of the stack unit through the fourth valve and the connecting pipe, and the fourth valve is used to control the flow of electrolyte to the inlet of the stack unit to ensure that the electrolyte can smoothly enter the stack unit for electrochemical reaction;

[0059] The system of this embodiment realizes the mutual conversion of electrical energy and chemical energy efficiently through the above-mentioned design, ensures that the electrolyte circulates in the system, and supports continuous charging and discharging reactions.

[0060] S3, the dynamic energy storage liquid flow circulation control system also includes a voltage sensor, a current sensor and a hydraulic sensor; the control system coordinates and controls the circulation pump, the lifting pump and the valve group to achieve liquid flow circulation control in the conventional operation stage and the command response stage, wherein:

[0061] S31, the conventional operation stage includes charging operation and self-balancing operation:

[0062] S311, Charging operation:

[0063] The control system receives a charging instruction and charges the single battery system;

[0064] The voltage sensor is installed on the battery stack unit of each single battery system. When the single battery system is charged, the control system detects the charge state of each single battery system in real time through the voltage sensor, and adjusts the single battery system with the goal of making the charge state of each single battery system consistent until charging is completed;

[0065] S312, self-balancing operation:

[0066] Initially, the first valve and the second valve corresponding to the liquid flow energy storage system are both in the open state, and the other valves in the valve group are all in the closed state;

[0067] The control system closes the first valve and the second valve corresponding to each single battery system, opens the third valve, and starts the lifting pump, so that the electrolyte in the anode electrolyte storage tank of the common battery system is lifted to the high-position anode electrolyte storage tank for connection, and the electrolyte in the cathode electrolyte storage tank of the common battery system is lifted to the high-position cathode electrolyte storage tank;

[0068] When the high-position anode electrolyte storage tank connection and the electrolyte in the high-position cathode electrolyte storage tank are raised to a preset height, the fourth valve and the fifth valve and the sixth valve corresponding to the liquid flow energy storage system are opened, and the electrolyte in the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank flows into the battery stack unit through the connecting pipe using gravitational potential energy, and flows from the battery stack unit into the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank;

[0069] When the corresponding liquid levels of the electrolyte in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank reach a preset height, the seventh valve is opened, and the electrolyte after the charging reaction in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank is lifted to the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank by the lifting pump;

[0070] S32, the instruction response phase is specifically as follows:

[0071] When the control system receives frequency modulation, peak modulation and discharge instructions, the first valve and the second valve corresponding to each single battery system are opened, and the fifth valve and the sixth valve corresponding to each single battery system are closed, and each single battery system performs self-circulation;

[0072] The third valve and the sixth valve corresponding to the common battery system are closed, and the second valve corresponding to the common battery system is opened, so that the electrolyte in the high-positioned anode electrolyte storage tank and the high-positioned cathode electrolyte storage tank flows back to the anode electrolyte storage tank and the cathode electrolyte storage tank of the common battery system;

[0073] When the electrolyte in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank in the liquid circulation operation is emptied, the lifting pump and the seventh valve are closed; when the electrolyte in the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank is refluxed, the first valve corresponding to the common battery system is opened, the fourth valve and the fifth valve corresponding to the common battery system are closed, and the common battery system performs self-circulation;

[0074] The inverter is used to convert the direct current generated by the electrochemical reaction of the battery stack unit into alternating current and provide it to the power grid for use;

[0075] Preferably, the current sensor is installed on the inlet and outlet connecting pipes of the circulation pump and the lifting pump to monitor the flow current of the electrolyte; the liquid level sensor is installed in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank to monitor the liquid level changes of the electrolyte in real time to ensure the safe operation of the system.

[0076] Example 2

[0077] This embodiment provides the charging module for charging each battery system in the common battery system when the instruction is not reached; the control system pre-detects and adjusts the state of charge of the electrolyte in the cathode and anode storage tanks of each battery system, closes the valves and circulation pumps of each battery system, and charges each battery unit;

[0078] When the common battery system enters the energy storage stage, the control system controls the common valve and the lifting pump to lift the electrolyte in the electrolyte storage tank of the common battery system to the high-level electrolyte storage tank; when the electrolyte in the high-level electrolyte storage tank reaches a preset height, the electrolyte in the high-level electrolyte storage tank is pressed into the battery stack unit of each battery system by using the gravitational potential energy, and flows through each battery stack unit and then flows back to the low-level electrolyte storage tank; when the electrolyte in the low-level electrolyte storage tank reaches a preset height, the common valve and the lifting pump are opened to lift the electrolyte back to the high-level electrolyte storage tank; the electrolyte continuously flows in the high-level electrolyte storage tank, the low-level electrolyte storage tank and the battery stack unit in turn to form an electrolyte circulation;

[0079] The discharge module is used in the command arrival stage, the common battery system enters the discharge stage, the control system controls the inverter to start the discharge according to the command, and when the circulation pump pressure of each battery system reaches the preset value, the valve is switched to make the electrolyte flow out from the cathode and anode electrolyte storage tanks of each battery stack unit and flow through the battery stack unit to realize the self-circulation of the battery stack unit;

[0080] The control system controls the common battery system valve to return the electrolyte in the high-level electrolyte storage tank to the common battery system electrolyte storage tank; drains the electrolyte in the low-level electrolyte storage tank, and closes the lifting pump and valve; drains the electrolyte in the high-level electrolyte tank, starts the common battery system circulation pump, and waits until the pressure of the common battery system circulation pump reaches a preset value; controls the switch common valve to achieve self-circulation of the common battery system; each battery system discharges to a stop state according to the instructions issued, enters the charging stage, and waits for the next cycle.

[0081] Preferably, the method further comprises, during the circulation of the electrolyte, respectively monitoring the flow current and the liquid level change of the electrolyte by means of a current sensor and a liquid level sensor, so as to achieve dynamic control of the liquid flow energy storage system.

[0082] It is worth noting that the system described in the present invention is based on the same principle as the method described in Example 2, which will not be repeated here.

[0083] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A dynamic energy storage liquid flow circulation control system, characterized in that: The dynamic energy storage liquid flow circulation control system includes an inverter, a control system, a liquid flow energy storage system, a liquid flow circulation system, connecting pipes and a valve group. The liquid flow energy storage system includes multiple single battery systems and a common battery system. The single battery system and the common battery system both include a battery stack unit, an anode electrolyte storage tank, a cathode electrolyte storage tank and a circulation pump; the liquid flow circulation system includes a lifting pump, a low-position anode electrolyte storage tank, a low-position cathode electrolyte storage tank, a high-position anode electrolyte storage tank and a high-position cathode electrolyte storage tank. The valve group includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve and a seventh valve, wherein: The stack unit is connected to the anode electrolyte storage tank and the cathode electrolyte storage tank through a connecting pipe to form an electrolyte circulation loop, and the circulation loop uses a circulation pump to circulate the electrolyte; a sixth valve is provided at the positive and negative electrode outlets of the stack unit, and the stack unit is respectively connected to the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank through the sixth valve and the connecting pipe; A seventh valve is respectively provided at the outlet of the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank, and the seventh valve is used to control the electrolyte to flow to the lifting pump. The low-position anode electrolyte storage tank is connected to the high-position anode electrolyte storage tank through the seventh valve, the lifting pump and the connecting pipe, and the low-position cathode electrolyte storage tank is connected to the high-position cathode electrolyte storage tank through the seventh valve, the lifting pump and the connecting pipe; A fourth valve is provided at the outlet of the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank, which are connected to the inlet of the stack unit through the fourth valve and the connecting pipe, and the fourth valve is used to control the electrolyte to flow to the inlet of the stack unit; The control system coordinates and controls the circulation pump, the lifting pump and the valve group to achieve liquid flow circulation control in the normal operation stage and the command response stage.

2. The dynamic energy storage liquid flow circulation control system according to claim 1 is characterized in that: The circulation loop uses a circulation pump to circulate the electrolyte as follows: A circulation pump is provided at the outlet of the anode electrolyte storage tank and the cathode electrolyte storage tank, and a first valve is provided at the outlet of the circulation pump. Before starting the circulation pump, the first valve is closed first, and the pressure is held until a preset outlet pressure value is reached, and then the circulation pump is started; a second valve is provided at the inlet of the anode electrolyte storage tank and the cathode electrolyte storage tank. The first valve and the second valve are opened to transport the electrolyte from the anode electrolyte storage tank and the cathode electrolyte storage tank to the stack unit, and the electrolyte after participating in the electrochemical reaction is returned to the anode electrolyte storage tank and the cathode electrolyte storage tank for storage.

3. The dynamic energy storage liquid flow circulation control system according to claim 1 is characterized in that: A third valve is also provided at the outlet of the anode electrolyte storage tank and the cathode electrolyte storage tank of the common battery system respectively. The anode electrolyte storage tank of the common battery system is connected to the high-position anode electrolyte storage tank via the third valve, a lifting pump and a connecting pipe, and the cathode electrolyte storage tank of the common battery system is connected to the high-position cathode electrolyte storage tank via the third valve, a lifting pump and a connecting pipe.

4. The dynamic energy storage liquid flow circulation control system according to claim 3 is characterized in that: The lifting pump is used to lift the electrolyte in the low-positioned anode electrolyte storage tank and the anode electrolyte storage tank of the common battery system to the high-positioned anode electrolyte storage tank, and to lift the electrolyte in the low-positioned cathode electrolyte storage tank and the cathode electrolyte storage tank of the common battery system to the high-positioned cathode electrolyte storage tank.

5. The dynamic energy storage liquid flow circulation control system according to claim 4 is characterized in that: The normal operation stage includes charging operation and self-balancing operation, wherein the charging operation specifically charges the single battery system; the self-balancing operation specifically includes: The control system closes the first valve and the second valve corresponding to each single battery system, opens the third valve, and starts the lifting pump, so that the electrolyte in the anode electrolyte storage tank of the common battery system is lifted to the high-position anode electrolyte storage tank for connection, and the electrolyte in the cathode electrolyte storage tank of the common battery system is lifted to the high-position cathode electrolyte storage tank; When the high-position anode electrolyte storage tank connection and the electrolyte in the high-position cathode electrolyte storage tank are raised to a preset height, the fourth valve and the fifth valve and the sixth valve corresponding to the liquid flow energy storage system are opened, and the electrolyte in the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank flows into the battery stack unit through the connecting pipe using gravitational potential energy, and flows from the battery stack unit into the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank; When the corresponding liquid levels of the electrolyte in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank reach the preset height, the seventh valve is opened, and the electrolyte after the charging reaction in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank is lifted to the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank by the lifting pump.

6. The dynamic energy storage liquid flow circulation control system according to claim 5, characterized in that: The command response phase is as follows: When the control system receives frequency modulation, peak modulation and discharge instructions, the first valve and the second valve corresponding to each single battery system are opened, and the fifth valve and the sixth valve corresponding to each single battery system are closed, and each single battery system performs self-circulation; The third valve and the sixth valve corresponding to the common battery system are closed, and the second valve corresponding to the common battery system is opened, so that the electrolyte in the high-positioned anode electrolyte storage tank and the high-positioned cathode electrolyte storage tank flows back to the anode electrolyte storage tank and the cathode electrolyte storage tank of the common battery system; When the electrolyte in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank in the liquid circulation operation is emptied, close the lifting pump and the seventh valve; when the electrolyte reflux in the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank is completed, open the first valve corresponding to the common battery system, close the fourth valve and the fifth valve corresponding to the common battery system, and the common battery system performs self-circulation.

7. The dynamic energy storage liquid flow circulation control system according to claim 1, characterized in that: The inverter is used to convert the direct current generated during the discharge process of the battery stack unit into alternating current and provide it to the power grid for use.

8. The dynamic energy storage liquid flow circulation control system according to claim 1, characterized in that: The dynamic energy storage liquid flow circulation control system further includes a voltage sensor, a current sensor and a hydraulic pressure sensor, wherein: The voltage sensor is installed on the battery stack unit. When the single battery system is charged, the control system detects the charge state of each single battery system in real time through the voltage sensor, and adjusts the single battery system with the goal of making the charge state of each single battery system consistent until charging is completed; The current sensor is installed on the inlet and outlet connecting pipes of the circulation pump and the lifting pump to monitor the flow current of the electrolyte; the liquid level sensor is installed in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank to monitor the liquid level changes of the electrolyte in real time.

9. A dynamic energy storage liquid flow circulation control method, characterized in that: The method comprises: The control system receives the charging instruction and charges the single battery system. When the single battery system is charged, the control system detects the charge state of each single battery system in real time through the voltage sensor, and adjusts the single battery system with the goal of making the charge state of each single battery system consistent until the charging is completed; After charging, the control system closes the first valve and the second valve corresponding to each single battery system, opens the third valve, and starts the lifting pump, so that the electrolyte in the anode electrolyte storage tank of the common battery system is lifted to the high-position anode electrolyte storage tank for connection, and the electrolyte in the cathode electrolyte storage tank of the common battery system is lifted to the high-position cathode electrolyte storage tank; When the high-position anode electrolyte storage tank is connected and the electrolyte in the high-position cathode electrolyte storage tank is lifted to a preset height, the fourth valve and the fifth and sixth valves corresponding to the liquid flow energy storage system are opened, and the electrolyte in the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank flows into the battery stack unit through the connecting pipe using gravitational potential energy, and flows from the battery stack unit into the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank; it is used to convert the direct current generated during the discharge of the battery stack unit into alternating current and provide it to the power grid. When the control system receives frequency modulation, peak regulation and discharge instructions, it opens the first and second valves corresponding to each single battery system, closes the fifth and sixth valves corresponding to each single battery system, and each single battery system performs self-circulation; The third valve and the sixth valve corresponding to the common battery system are closed, and the second valve corresponding to the common battery system is opened, so that the electrolyte in the high-positioned anode electrolyte storage tank and the high-positioned cathode electrolyte storage tank flows back to the anode electrolyte storage tank and the cathode electrolyte storage tank of the common battery system; When the electrolyte in the low-position anode electrolyte storage tank and the low-position cathode electrolyte storage tank in the liquid circulation operation is emptied, the lifting pump and the seventh valve are closed; when the electrolyte in the high-position anode electrolyte storage tank and the high-position cathode electrolyte storage tank is refluxed, the first valve corresponding to the common battery system is opened, the fourth valve and the fifth valve corresponding to the common battery system are closed, and the common battery system performs self-circulation; The inverter converts the direct current generated by the discharge of the battery stack unit into alternating current and provides it to the grid until the instruction is completed.

10. A dynamic energy storage liquid flow circulation control method according to claim 9, characterized in that: The method also includes monitoring the flow current and liquid level change of the electrolyte respectively by using a current sensor and a liquid level sensor during the circulation flow of the electrolyte, so as to realize dynamic control of the liquid flow energy storage system.

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