CN216793755U - Flow battery system based on underground space - Google Patents

Abstract

The application relates to the technical field of flow batteries, and provides a flow battery system based on underground space, which comprises: the first liquid storage tank is arranged underground and is used for storing a first electrolyte solution; the second liquid storage tank is used for storing a second electrolyte solution, and the second electrolyte solution and the first electrolyte solution are respectively used for generating electrochemical reactions with opposite polarities; and the galvanic pile is respectively communicated with the first liquid storage tank and the second liquid storage tank. The utility model provides a redox flow battery system's based on underground space first liquid storage pot locates the underground, so first liquid storage pot can not occupy subaerial space, and this just makes redox flow battery system's the stock solution container that is used for storing electrolyte solution can not occupy the ground space to save redox flow battery system's occupation of land space, saved occupation of land cost.

Description

A flow battery system based on underground space

technical field

The present application relates to the technical field of flow batteries, and in particular, to an underground space-based flow battery system.

Background technique

The flow battery system is a new type of electric energy storage and high-efficiency conversion device, which has the characteristics of large storage capacity, long life, high efficiency, non-toxic and environmentally friendly. The flow battery system includes two electrolyte reservoirs, a stack, and electrolyte inlet and outlet pipelines for transporting electrolyte. Among them, the two electrolyte reservoirs are respectively used for containing the positive electrolyte and the negative electrolyte.

The energy of the electrolyte of the flow battery determines the power of the flow battery, so the volume of the reservoir of the flow battery is usually large to hold more electrolyte, so that the energy of the electrolyte is more, so the flow The volume of the battery system is usually relatively large, resulting in a large footprint and high cost of the flow battery system.

Utility model content

The embodiments of the present application provide a flow battery system based on an underground space, which can reduce the footprint of the flow battery system, thereby reducing the footprint cost. The specific plans are as follows:

Embodiments of the present application provide a flow battery system, including:

a first liquid storage tank, the first liquid storage tank is arranged underground and is used for storing the first electrolyte solution;

a second liquid storage tank for storing a second electrolyte solution, where the second electrolyte solution and the first electrolyte solution are respectively used for electrochemical reactions with opposite polarities;

The electric stack is respectively communicated with the first liquid storage tank and the second liquid storage tank.

The first liquid storage tank of the flow battery system based on the underground space provided by the embodiment of the present application is arranged underground, so the first liquid storage tank does not occupy space on the ground, which makes the flow battery system for storing electrolytes The liquid storage container of the solution does not occupy the floor space, thereby saving the floor space and cost of the flow battery system.

Optionally, the flow battery system further includes:

A first liquid storage chamber, the first liquid storage chamber is an underground space, and the first liquid storage tank is set in the first liquid storage chamber.

In this embodiment, by setting the first liquid storage chamber, it is more convenient for the first liquid storage tank to be installed underground. The setting of the first liquid storage chamber can also provide better space for maintenance, which is more convenient for maintenance and more convenient for the flow battery system. Other components are arranged in the first liquid storage chamber.

Optionally, a manual detection space is provided between the first liquid storage tank and the inner side wall of the first liquid storage chamber, and a first manual detection channel is provided between the manual detection space and the ground.

After the manual detection channel is set in this embodiment, the detection personnel can enter the manual detection space from the manual detection channel, so that the first liquid storage tank can be maintained and tested from the outside of the first liquid storage tank in the manual detection space.

Optionally, the flow battery system further includes a control system, a liquid leakage detection device is provided at the bottom of the first liquid storage chamber, the liquid leakage detection device is located outside the first liquid storage tank, and is connected with the first liquid storage tank. The control system is communicatively connected.

In this embodiment, a liquid leakage detection device is provided at the bottom of the first liquid storage chamber, which can quickly detect the leakage of the first liquid storage tank, so as to facilitate timely maintenance by operators and reduce adverse consequences caused by leakage.

Optionally, an anti-corrosion layer is provided on the inner wall of the first liquid storage chamber.

In this embodiment, an anti-corrosion layer is arranged on the inner wall of the first liquid storage chamber, so that when the first liquid storage tank leaks, the chamber wall of the first liquid storage chamber will not be corroded or damaged, and will not pass through the first liquid storage tank. The wall of the liquid storage chamber is immersed into the ground, so that the leakage of the liquid can be better prevented from immersing into the ground and destroying the ecological environment.

Optionally, a liquid conveying channel is provided between the first liquid storage tank and the ground.

In this embodiment, the provision of the liquid delivery channel makes it easier to input the electrolyte solution into the first liquid storage tank, or to extract the electrolyte solution from the first liquid storage tank, which improves the convenience of accessing the electrolyte solution.

Optionally, the electric stack is arranged in an underground space, and a power cable leading to the ground is electrically connected to the electric stack.

In this embodiment, the electric stack is arranged in the underground space, so that the distance between the electric stack and the first liquid storage tank can be set relatively close, so that the connection between the electric stack and the first liquid storage tank is more convenient through pipelines. In addition, the stack is placed in the underground space, thanks to the better thermal conductivity of the underground soil and rock walls, the heat generated during the operation of the stack can be released in time, so that the temperature of the stack is not easily affected by excessively high In addition, the temperature difference in the underground space changes very little, and the temperature is relatively stable, so that the working environment of the stack is not easy to be too low, so that the stack can operate more reliably and is conducive to the thermal management of the stack.

In addition, since the height difference between the electric stack arranged underground and the first liquid storage tank is small, the work required by the circulating pump can also be effectively reduced, and the energy storage efficiency of the flow battery system is improved. By arranging the stack in the underground space, the floor space and cost of the flow battery can be further reduced.

Optionally, a second manual detection channel is provided between the underground space where the electric stack is located and the ground, and the power cable is located in the second manual detection channel.

In this embodiment, the energized cable is led to the ground through the second manual detection channel, so that the operator can detect the energized cable through the second manual detection channel. In addition, the operator can also reach the location of the stack from the second manual detection channel. underground space for inspection and maintenance of the stack, etc.

Optionally, an air flow channel is provided between the underground space where the electric stack is located and the ground, and the air flow channel is arranged separately from the second manual detection channel.

The gas flow channel can discharge the hydrogen and other gases generated during the redox reaction of the stack to prevent explosion, improve the safety, and ensure the normal operation of the stack.

Optionally, the electric stack is set on the ground, the first liquid storage tank is provided with a liquid outlet, the electric stack is provided with a liquid inlet communicated with the liquid outlet, and the liquid outlet is provided on the stack. The height difference between the port and the liquid inlet is not more than 10 meters.

In this embodiment, the electric stack is arranged on the ground, which is more convenient to detect and maintain the electric stack, and the installation of the electric stack is also simpler. The height difference between the liquid outlet on the first liquid storage tank and the liquid inlet on the stack is not more than meters, and the height difference is relatively small, so that the electrolyte solution in the first liquid storage tank can also be easily pumped into the stack.

Optionally, the side wall of the first liquid storage chamber is in contact with the side wall of the first liquid storage tank to support the side wall of the first liquid storage tank.

Since the first liquid storage chamber supports the side wall of the first liquid storage tank, the side wall of the first liquid storage tank can be made thinner, so that the consumables and production costs of the first liquid storage tank can be reduced. At the same time, the structural stability of the first liquid storage tank can also be better guaranteed.

Optionally, the first liquid storage tank is a plastic tank, and the material of the plastic tank includes at least one of polyvinyl chloride, polypropylene, and polytetrafluoroethylene.

When the first liquid storage tank is a plastic tank, the chemical stability of the first liquid storage tank is better, the weight is lighter, the cost is lower, and the manufacturing is more convenient.

Optionally, the anti-corrosion layer is any one of epoxy anti-corrosion layer, phenolic resin anti-corrosion layer, silicon-titanium oxide composite anti-corrosion layer, and polyvinyl chloride free foam board.

Description of drawings

1 is a schematic structural diagram of an example of an underground space-based flow battery system provided by an embodiment of the present application;

2 is a schematic structural diagram of another example of an underground space-based flow battery system provided by an embodiment of the present application;

3 is a schematic structural diagram of yet another example of an underground space-based flow battery system provided by an embodiment of the present application;

FIG. 4 is a schematic structural diagram of another example of the flow battery system based on the underground space provided by the embodiment of the present application.

The symbols in the figure are:

110, the first liquid storage chamber; 111, the liquid delivery channel; 113, the artificial detection space; 114, the first manual detection channel; 120, the first liquid storage tank; 130, the electric stack; Two artificial detection channels; 134, bipolar plate; 135, collector plate; 136, end plate; 137a, positive electrode; 137b, negative electrode; 137c, ion exchange membrane; 138, liquid inlet pipe; 138a, circulating pump; 139 140, the second liquid storage chamber; 150, the second liquid storage tank; 160, the power conversion system; 161, the power conversion system for charging; 162, the power conversion system for discharging; 170, the control system; 180, battery detection sensor;

10. Ground; 20. Wind power generation system; 30. Solar power generation system; 40. External power grid.

Detailed ways

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application. Wherein, in the description of the embodiments of the present application, unless otherwise stated, “/” means or means, for example, A/B can mean A or B; “and/or” in this document is only a description of the associated object The association relationship of , indicates that there can be three kinds of relationships, for example, A and/or B, can indicate that A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "plurality" refers to two or more than two.

Hereinafter, the terms "first", "second" and "third" are only used for descriptive purposes, and should not be understood as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first", "second", "third" may expressly or implicitly include one or more of that feature.

With the intensification of energy crisis and environmental pollution, renewable energy power generation such as wind power generation and photovoltaic power generation has developed rapidly. A large proportion of wind power generation and photovoltaic power generation have been connected to the grid, but the wind power generation volume changes with the change of wind speed and wind direction, and there are seasonal characteristics, and the power generation volume varies in different regions and seasons; At the same time, the fluctuation of temperature also has an impact on photovoltaic power generation. Generally, the maximum power is distributed at noon during the daytime in spring and winter. It can be seen that the power generation of new energy sources such as wind power and photovoltaics is highly volatile, unpredictable, and uncontrollable, which makes the grid dispatching difficult and greatly restricts the development of wind power and photovoltaics.

When a large number of new energy sources are integrated into the power grid, the fluctuation of the power grid will increase, and the security of the power grid may be affected. Therefore, large-scale energy storage technology and wind power generation technology can be combined to improve the controllability of wind power output power and facilitate the scheduling of power grid peak regulation and frequency regulation.

The existing large-scale energy storage technologies are mainly electrochemical energy storage and pumped water energy storage. The pumped hydro storage technology is mature and safe, but it has disadvantages such as being greatly restricted by the geographical environment and inflexible in the form of electricity storage, which makes it impossible to popularize and apply pumped hydro energy storage on a large scale.

Electrochemical energy storage is generally divided into lithium batteries, lead-acid batteries and flow batteries. The safety of lithium batteries is low; lead-acid batteries have low power, and the charging and discharging process will consume metal electrodes, resulting in power reduction and low life. Flow batteries can convert electrical energy into chemical energy and store it in the electrolyte. According to research, the electrolyte solutions of all-vanadium flow batteries and iron-chromium flow batteries can be recycled repeatedly, with high safety and long life. and good charging and discharging characteristics, so it is more and more used in new energy fields such as wind power and power grid peak regulation and frequency regulation.

Below, the principle of the flow battery is briefly introduced with reference to the accompanying drawings.

As shown in FIG. 1 and FIG. 4 , the flow battery mainly includes components such as a liquid storage tank, an electric stack 130 , a pipeline system, and a circulating pump 138 a.

The liquid storage tank includes a first liquid storage tank 120 and a second liquid storage tank 150, which are respectively used for containing the positive electrolyte solution and the negative electrode electrolyte solution. The piping system is used to communicate the liquid storage tank and the stack 130 , and the circulation pump 138 a is used to make the electrolyte solution flow between the liquid storage tank and the stack 130 .

As shown in FIG. 1 , the flow battery may include one stack 130 , and as shown in FIG. 4 , the flow battery may also include multiple stacks 130 .

As shown in FIG. 1 , the stack 130 may include one or more stack units, adjacent stack units are separated by bipolar plates 134 , and current collector plates 135 are provided on both sides of the stack 130 respectively. 135 is used for connecting with an external circuit to conduct current introduction or extraction, an end plate 136 is provided on the outer side of the current collecting plate 135, and the end plate 136 is used for fixing a plurality of stack units. The stack unit includes a positive electrode 137a and a negative electrode 137b, and an ion exchange membrane 137c is provided between the positive electrode 137a and the negative electrode 137b.

The stack 130 is the main place for electrode reaction, and the electrode area of the stack 130 and the number of stack units determine the output power of the flow battery. The electrolyte solution is the energy storage medium, and the concentration and volume of the electrolyte solution determine the energy storage capacity of the flow battery, which makes the design of the flow battery more flexible.

The electrode of the flow battery only provides a reaction interface for the active material, and does not perform electrochemical reaction itself. The positive and negative active materials are usually stored in the electrolyte in an ionic state, and are placed in the positive and negative storage tanks respectively. During the charging and discharging process, the electrolyte enters the stack 130 through the circulating pump 138a, and a redox reaction occurs on the electrode surface to realize the mutual conversion of chemical energy and electrical energy.

In the following, the energy storage principle of the flow battery is briefly introduced by taking the all-vanadium flow battery as an example.

离子(5价钒离子)，负极电解液包括V²⁺离子(2价钒离子)和V³⁺离子(3价钒离子)，钒离子通过电解质溶液的方式存储于储液罐中，系统通过循环泵138a使电解质溶液进入电堆130内发生氧化还原反应。As shown in Figure 1 and Figure 4, the electrical energy in the all-vanadium redox flow battery is stored in the acid electrolyte of different valence vanadium ions in the form of chemical energy. The positive electrolyte includes VO ²⁺ ions (tetravalent vanadium ions) and

ions (5-valent vanadium ions), the negative electrolyte includes V ²⁺ ions (2-valent vanadium ions) and V ³⁺ ions (3-valent vanadium ions), and the vanadium ions are stored in the liquid storage tank through the electrolyte solution, and the system passes The circulation pump 138a enables the electrolyte solution to enter the stack 130 for redox reaction.

As shown in FIG. 1 and FIG. 4 , under the action of the circulating pump 138a, the positive electrolyte solution flows into the area where the positive electrode is located in the stack 130, and then flows out from the stack 130 after the reduction reaction of the positive electrode occurs, and flows into the first storage solution The negative electrode electrolyte solution flows into the area where the negative electrode is located in the stack 130, and then flows out from the stack 130 after the negative electrode undergoes an oxidation reaction, and flows into the second liquid storage tank 150, and the cycle proceeds. The ion exchange membrane 137c allows ions to pass under the action of the concentration difference and the potential difference, and the ion exchange membrane 137c blocks the electrolytes of the positive and negative electrodes 137b to avoid self-discharge.

The above-mentioned positive electrode 137a and negative electrode 137b may be porous electrodes, and the active material (ie, the ions included in the electrolyte) undergoes a redox reaction on the surface of the porous electrodes, and current is collected and conducted through the bipolar plate 134, so that the ions stored in the electrolyte solution. Chemical energy is converted into electrical energy. The principle of the iron-chromium flow battery and the all-vanadium flow battery is similar, and will not be repeated here.

Compared with other energy storage mechanisms, all-vanadium flow batteries and iron-chromium flow batteries have many technical advantages, especially in terms of manufacturing cost, full cycle life, energy efficiency and safety. However, the energy density of these two flow batteries is relatively low, about 20Wh/L to 30Wh/L. In the actual use process, the energy density of the flow battery is lower than the theoretical value, about less than 20Wh/L. Therefore, in order to store more electricity, more electrolyte solution is needed, which makes the liquid storage of the flow battery system. Tanks are often bulky, resulting in a large floor space.

Therefore, the present application provides a flow battery system, which uses underground space to place the flow battery system, which can reduce the floor space of the flow battery system, thereby reducing the floor space cost, and can greatly reduce the cost of the flow battery system. Reduce the reliance of flow batteries on ground space.

As shown in FIG. 2 to FIG. 4 , the underground space-based flow battery system provided by the embodiment of the present application includes: a first liquid storage tank 120 , a second liquid storage tank 150 , and an electric stack 130 .

The first liquid storage tank 120 is arranged underground and is used to store the first electrolyte solution, the second liquid storage tank 150 is used to store the second electrolyte solution, and the second electrolyte solution and the first electrolyte solution are respectively used to generate electricity with opposite polarities. For chemical reaction, the stack 130 is communicated with the first liquid storage tank 120 and the second liquid storage tank 150 respectively.

In the embodiment of the present application, the first liquid storage tank 120 is arranged underground, which means that the first liquid storage tank 120 is located under the ground as a whole. The first liquid storage tank 120 may be buried underground, or the first liquid storage tank 120 may also be placed in a space provided underground.

In the embodiment of the present application, the second electrolyte solution may be a positive electrode electrolyte solution, and the first electrolyte solution may be a negative electrode electrolyte solution, or the second electrolyte solution may be a negative electrode electrolyte solution, and the first electrolyte solution may be a positive electrode electrolyte solution.

The above-mentioned second liquid storage tank 150 may be installed on the ground or underground. In order to further reduce the floor space of the flow battery system, the second liquid storage tank 150 may be arranged underground.

The above-mentioned first liquid storage tank 120 may be a metal tank, a plastic tank, etc., or may be a tank body made of other materials. When the first liquid storage tank 120 is a plastic tank, the chemical stability of the first liquid storage tank 120 is better, the weight is lighter, the cost is lower, and the manufacturing is more convenient.

Specifically, the material of the first liquid storage tank 120 may be at least one of polyvinyl chloride, polypropylene, and polytetrafluoroethylene, and the plastic tank may also be made of other materials with relatively stable chemical properties, which are not specifically limited in this application.

The shape of the first liquid storage tank 120 may be cylindrical, truncated, cubic, etc., and may also be other regular or irregular shapes.

The depth of the first liquid storage tank 120 in the ground can be selected according to the local geothermal temperature rise curve. Specifically, when the flow battery is an all-vanadium flow battery, the temperature of the environment where the first liquid storage tank 120 is located is selected at 15° C. Between ~35°C, when the flow battery is an iron-chromium flow battery, the temperature of the environment where the first liquid storage tank 120 is located is selected to be between 45°C and 70°C.

For the material, shape and arrangement of the second liquid storage tank 150, reference may be made to the first liquid storage tank, which will not be repeated here.

The first liquid storage tank 120 of the flow battery system provided in the embodiment of the present application is set underground, so the first liquid storage tank 120 does not occupy space on the ground, which makes the flow battery system for storing electrolyte solution. The liquid storage container does not occupy the floor space, thereby saving the floor space of the flow battery system and saving the cost of the floor space.

In the present application, the first liquid storage tank 120 is set underground. Thanks to the better thermal conductivity of the underground soil and rock wall, the heat generated during the operation of the flow battery system can be released in time, so that the first liquid storage tank 120 is stored in the first liquid storage tank 120. The temperature of the electrolyte solution is not easy to be too high. In addition, the first liquid storage tank 120 located underground has little heat exchange with the atmosphere, so the temperature difference of the environment where the first liquid storage tank 120 is located is not easy to change greatly with the change of the atmospheric temperature, that is, the first liquid storage tank 120 is not easily changed. The temperature difference of the environment where the tank 120 is located changes little, and the temperature is relatively stable. When the ground temperature is low, the temperature of the electrolyte solution in the first liquid storage tank 120 located underground is not too low. In this way, it can better ensure that the electrolyte solution works in a stable ambient temperature, so that the chemical properties of the electrolyte solution are more stable, so that the flow battery system is more stable and reliable, and the energy consumption for temperature control of the electrolyte solution can also be reduced.

In one embodiment, as shown in FIGS. 2 to 4 , the flow battery system may further include: a first liquid storage chamber 110 , the first liquid storage chamber 110 is an underground space, and a first liquid storage tank 120 It is arranged in the first liquid storage chamber 110 .

The above-mentioned first liquid storage chamber 110 may be a cave located underground, and the cave may be a rock cave or an earth cave.

When the first liquid storage chamber 110 is an underground soil hole, the first liquid storage chamber 110 can be formed by drilling a hole with a pile driver, and the inner wall of the soil hole can be compacted, so that the structure of the first liquid storage chamber 110 can be formed. Better stability.

The size of the first liquid storage chamber 110 can be determined according to the capacity (energy storage capacity) of the flow battery. The greater the volume of electrolyte solution that can be stored in the liquid storage tank 120, the greater the capacity of the flow battery.

The shape of the first liquid storage chamber 110 may be cylindrical, cubic, truncated, etc., and may also be any other regular or irregular shape. Those skilled in the art can design the shape and size of the first liquid storage chamber 110 according to the actual situation, which is not specifically limited in this application.

The shape of the first liquid storage chamber 110 may correspond to the shape of the first liquid storage tank 120. For example, when the first liquid storage tank 120 is cylindrical, the first liquid storage chamber 110 may also be cylindrical. When the first liquid storage tank 120 is in the shape of a cube, the first liquid storage chamber 110 can also be in the shape of a cube, so that the space of the first liquid storage chamber 110 can be more fully utilized, so that the first liquid storage tank 120 can store more The more electrolyte solution improves the energy storage capacity of the flow battery system.

Optionally, as shown in FIG. 2 , a liquid conveying channel 111 may be provided between the first liquid storage tank 120 and the ground, and the above-mentioned liquid conveying channel 111 may be a pipe, through which the first liquid storage tank 120 can be sent to the first liquid storage tank 120 . The electrolyte solution is added to the electrolyte solution, or the electrolyte solution is drawn out from the first liquid storage tank 120 .

The end of the liquid delivery channel 111 leading to the ground 10 may be provided with a cover. When the electrolyte solution needs to be extracted or added, the cover may be opened. After the extraction or addition, the cover may be closed.

As shown in FIG. 2 and FIG. 4 , a liquid inlet pipe 138 and a liquid outlet pipe 139 may be provided between the above-mentioned stack 130 and the first liquid storage tank 120 , and the liquid inlet pipe 138 is used for connecting the liquid in the first liquid storage tank 120 The electrolyte solution flows into the stack 130, the liquid outlet pipe 139 is used to flow the reacted electrolyte solution in the stack 130 into the first liquid storage tank 120, and the liquid inlet pipe 138 and the liquid storage pipe are two separate pipes. .

A circulation pump 138a may be provided on the liquid inlet pipe 138 and/or the liquid outlet pipe 139, and the electrolyte solution in the first liquid storage tank 120 can flow into the stack 130 through the circulation pump 138a, and flow out from the stack 130 into the first storage tank. liquid tank 120. The circulating pump 138a can be electrically connected with a power cable leading to the ground 10, the circulating pump 138a is connected to the power supply on the ground 10 through the power cable, and the circulating pump 138a can also be connected in communication with the control system 170, so that the control system 170 can The on-off and the rotational speed of the circulating pump 138a are controlled.

The aforementioned control system 170 may also be referred to as a battery management system (Battery Management System, BMS for short).

Valves may be provided on the liquid inlet pipeline 138 and the liquid storage pipeline, and each valve is connected to the control system 170 through a cable, and the control system 170 controls the opening and closing state of each pipeline through the valve.

The communication manner between the second liquid storage tank 150 and the stack 130 may refer to the first liquid storage tank 120 , and details are not described herein again.

Optionally, a temperature sensor and a flow rate sensor may be provided in the stack 130, and the control system 170 may obtain flow rate data of the flow rate sensor in the stack 130, and control the working state of the circulating pump 138a according to the flow rate data, so as to adjust the flow rate. The stack 130 may include a temperature control device, and the control system 170 may acquire temperature data of a temperature sensor in the stack 130 and control the operation of the temperature control device of the stack 130 according to the temperature data, so that the stack 130 maintains a normal working temperature.

Taking the first electrolyte solution stored in the first liquid storage tank 120 as the positive electrode electrolyte solution as an example, the circulating flow process of the positive electrode electrolyte solution is: The liquid pipeline 138 flows into the area where the positive electrode is located in the stack 130 to carry out the reduction reaction, and the reacted positive electrolyte solution flows out from the liquid outlet pipeline 139 under the action of the circulating pump 138a and flows into the first liquid storage tank 120 and into the first liquid storage tank 120. The positive electrolyte solution in a storage tank 120 has chemical energy and can be discharged.

In order to improve the power of the flow battery system, as shown in FIG. 4 , the flow battery system may include a plurality of electric stacks 130 , and the plurality of electric stacks 130 are respectively communicated with the first liquid storage tank 120 . The output power of the stack 130 may range from 1KW to 250KW, and those skilled in the art can select the required output power of the stack 130 according to actual requirements.

By arranging the first liquid storage chamber 110 in this embodiment, it is more convenient for the first liquid storage tank 120 to be installed underground.

For the all-vanadium redox flow battery, when the operating temperature is lower than 10°C, the V ²⁺ ions and V ³⁺ ions on the negative side will precipitate, and when the temperature is higher than 40°C, the VO ²⁺ ions on the positive side will occur. Thermal precipitation. It can be seen that the flow battery system also has certain requirements on the ambient temperature, therefore, the temperature control requirements in the liquid storage tank are relatively high.

In addition, since the electrolyte solution is rich in acid, alkali, or heavy metal ions, when the liquid storage tank for storing the electrolyte solution leaks, it is easy to quickly flow to the surroundings and cause great pollution to the environment. In the embodiment of the present application, the first liquid storage tank 120 is arranged in the first liquid storage chamber 110 underground. Even if the first liquid storage tank 120 leaks, most of the leaked electrolyte solution is located in the first liquid storage chamber 110 and does not leak. Larger leakage is easy to occur, therefore, it is not easy to cause pollution to the environment.

In one embodiment, as shown in FIG. 2 and FIG. 3 , the flow battery system may further include a power conversion system 160 , the power conversion system 160 is arranged on the ground 10 , and the power conversion system 160 is electrically connected to the stack 130 . The conversion system 160 is used to electrically connect with the external power grid 40 for power transmission.

The power conversion system 160 may include, but is not limited to, transformers, converters, rectifiers, and the like.

In one embodiment, an anti-corrosion layer may be provided on the inner wall of the first liquid storage chamber 110 .

It can be understood that the material of the anti-corrosion layer should be a material that is not easy to chemically react with acid, alkali, heavy metal ions, etc., for example, the anti-corrosion layer can be epoxy anti-corrosion layer, phenolic resin anti-corrosion layer, silicon titanium oxide Any one of composite anti-corrosion layer and polyvinyl chloride free foam board, but not limited to this.

In this embodiment, an anti-corrosion layer is provided on the inner wall of the first liquid storage chamber 110, so that when the first liquid storage tank 120 leaks, the chamber wall of the first liquid storage chamber 110 will not be corroded or damaged, and no corrosion will occur. The chamber wall of the first liquid storage chamber 110 is immersed into the ground, so that the leakage of liquid can be better avoided from immersing into the ground and damaging the ecological environment.

In one embodiment, a liquid leakage detection device may be provided at the bottom of the first liquid storage chamber 110, the liquid leakage detection device is located outside the first liquid storage tank 120, and the liquid leakage detection device and the control system of the flow battery system 170 communication connections.

The above-mentioned control system 170 may be installed in a place such as an operation room that is convenient for operators to check in time. The control system 170 can monitor the working state of the flow battery in real time, which is beneficial to maintenance.

The liquid leakage detection device is connected in communication with the control system 170. When the liquid leakage detection device detects liquid leakage, it sends a liquid leakage signal to the control system 170. After receiving the liquid leakage signal, the control system 170 can send a prompt message to remind the operator Check and repair.

The liquid leakage detection device may be a point type liquid leakage sensor, a belt-shaped (also called wire or rope type) liquid leakage sensor, or other devices capable of detecting liquid leakage, which are not specifically limited in this application.

In this embodiment, a liquid leakage detection device is provided at the bottom of the first liquid storage chamber 110, which can quickly detect the leakage of the first liquid storage tank 120, so as to facilitate timely maintenance by operators and reduce adverse consequences caused by leakage .

In one embodiment, the side wall of the first liquid storage chamber 110 and the side wall of the first liquid storage tank 120 may be in contact to support the side wall of the first liquid storage tank 120 .

In this embodiment, the inner side wall of the first liquid storage chamber 110 is in contact with the outer side wall of the first liquid storage tank 120 , and the inner side wall of the first liquid storage chamber 110 supports the outer side wall of the first liquid storage tank 120 .

In this embodiment, the entire outer side wall of the first liquid storage tank 120 may be in contact with the first liquid storage chamber 110 , so that the entire outer side wall of the first liquid storage tank 120 is covered by the side wall of the first liquid storage chamber 110 support. The shape of the first liquid storage chamber 110 and the shape of the first liquid storage tank 120 can be matched. For example, the first liquid storage chamber 110 is a cylindrical space, and the first liquid storage tank 120 can also be a cylindrical tank body. The side wall of a liquid storage tank 120 can be better supported by the first liquid storage chamber 110 .

Alternatively, a part of the outer side wall of the first liquid storage tank 120 may be in contact with the first liquid storage chamber 110 to partially support the first liquid storage tank 120 , which can also improve the strength of the first liquid storage tank 120 . For example, the first liquid storage tank 120 is a cylindrical tank body, and the first liquid storage chamber 110 is in the shape of a cube. The side walls can support the side walls of the first liquid storage tank 120 that are in contact.

In this embodiment, since the first liquid storage chamber 110 supports the side wall of the first liquid storage tank 120, the side wall of the first liquid storage tank 120 can be made thinner, so that the first liquid storage tank 120 can be made thinner. Consumables and production costs of the liquid storage tank 120, and at the same time, the structural stability of the first liquid storage tank 120 can also be better guaranteed.

In one embodiment, as shown in FIG. 2 , there may be a manual detection space 113 between the first liquid storage tank 120 and the inner side wall of the first liquid storage chamber 110 , and a first detection space 113 is provided between the manual detection space 113 and the ground 10 . A manual detection channel 114 .

After the manual detection channel is provided in this embodiment, the detection personnel can enter the manual detection space 113 from the manual detection channel, so that the first liquid storage tank 120 can be maintained in the manual detection space 113 from the outside of the first liquid storage tank 120 , detection.

In the embodiment of the present application, when the entire outer side wall of the first liquid storage tank 120 is the same as the side wall of the first liquid storage chamber 110 , there is no space between the first liquid storage tank 120 and the first liquid storage chamber 110 for manual detection. The space 113, in this case, the top of the first liquid storage chamber 110 can lead to the ground 10, the top of the first liquid storage chamber 110 has an opening, and the opening at the top of the first liquid storage chamber 110 is covered by a cover body. When repairing the first liquid storage tank 120 , the cover body can be opened, and the first liquid storage tank 120 can be pulled out from the opening at the top of the first liquid storage chamber 110 .

In one embodiment, as shown in FIG. 2 to FIG. 4 , the electric stack 130 may be arranged in an underground space, and the electric power cable 131 leading to the ground 10 is electrically connected to the electric stack 130 .

An anti-corrosion layer may also be provided on the inner wall of the space where the stack 130 is located. The specific material of the anti-corrosion layer may refer to the material of the anti-corrosion layer on the inner wall of the first liquid storage chamber 110, which will not be repeated here.

In this embodiment, the underground depth where the stack 130 is located may be substantially the same as the underground depth where the first liquid storage chamber 110 is located, so that the stack 130 and the first liquid storage chamber 110 are communicated with each other through a pipeline.

Specifically, the underground space for placing the stack 130 may be formed by drilling holes with a pile driver.

The energizing cable 131 connected to the stack 130 may specifically be electrically connected to the above-mentioned power conversion system 160 .

As shown in FIG. 4 , the power conversion system 160 may include a power conversion system 161 for charging and a power conversion system 162 for discharging. The energization cable 131 connected to the stack 130 may include a charging cable and a discharging cable. The charging cable is connected to The charging power conversion system 161 is electrically connected, and the discharging cable is electrically connected to the discharging power conversion system 162 .

In this embodiment, the electric stack 130 is arranged in the underground space, so that the distance between the electric stack 130 and the first liquid storage tank 120 can be set relatively close, so that the distance between the electric stack 130 and the first liquid storage tank 120 is closer. Easy to connect via pipes. In addition, the electric stack 130 is arranged in the underground space, thanks to the better thermal conductivity of the underground soil and rock wall, the heat generated during the operation of the electric stack 130 can be released in time, so that the temperature of the electric stack 130 is not easy to exceed In addition, the temperature difference in the underground space changes very little, and the temperature is relatively stable, so that the working environment of the stack 130 is not easy to be too low, so that the stack 130 can operate more reliably, which is beneficial to the thermal management of the stack 130 .

In addition, since the height difference between the electric stack 130 located underground and the first liquid storage tank 120 is small, the work required by the circulating pump 138a can also be effectively reduced, thereby improving the energy storage efficiency of the flow battery system. By arranging the stack 130 in the underground space, the floor space and cost of the flow battery can be further reduced.

In an optional embodiment, when the stack 130 is arranged in an underground space, the height of the first liquid storage chamber 110 from the ground 10 can be set relatively high, for example, the first liquid storage chamber 110 is from the ground 10 The height of the battery can be not less than 10 meters, so that the electrolyte solution can be less easily affected by the temperature change of the external environment, thereby making the performance of the flow battery system more reliable.

In a specific embodiment, as shown in FIG. 2 , a second manual detection channel 132 may be provided between the underground space where the stack 130 is located and the ground 10 , and the power cable 131 is located in the second manual detection channel 132 .

In this embodiment, the energized cable 131 is led to the ground 10 through the second manual detection channel 132, so that the operator can detect the energized cable 131 through the second manual detection channel 132. In addition, the operator can also detect the energized cable 131 from the second manual detection channel 132. The channel 132 reaches the underground space where the stack 130 is located, so that the stack 130 can be inspected and maintained.

In one embodiment, an air flow channel may be provided between the underground space where the stack 130 is located and the ground 10 , and the air flow channel is provided separately from the second manual detection channel 132 .

The gas flow channel can discharge gas such as hydrogen gas generated during the redox reaction of the stack 130 to prevent explosion, improve safety, and ensure the normal operation of the stack 130 .

In one embodiment, the stack 130 can also be arranged on the ground 10 , the first liquid storage tank 120 is provided with a liquid outlet, the stack 130 is provided with a liquid inlet communicated with the liquid outlet, and the liquid outlet is provided on the stack 130 . The height difference with the liquid inlet is not more than 10 meters.

Specifically, the liquid outlet on the first liquid storage tank 120 can be communicated with the liquid inlet on the stack 130 through a pipeline. After the electrolyte solution in the first liquid storage tank 120 flows out from the liquid outlet, it flows into the stack through the pipeline. 130 for the oxidation/reduction reaction.

The height difference between the liquid outlet on the first liquid storage tank 120 and the liquid inlet on the stack 130 may be 1 meter, 3 meters, 5 meters, 8 meters, or 10 meters, etc., but is not limited thereto.

In this embodiment, the electric stack 130 is arranged on the ground 10 , which is more convenient for the detection and maintenance of the electric stack 130 , and the installation of the electric stack 130 is also simpler. The height difference between the liquid outlet on the first liquid storage tank 120 and the liquid inlet on the stack 130 is not more than 10 meters, and the height difference is relatively small. In this way, the electrolyte solution in the first liquid storage tank 120 can also be relatively It is easily drawn into the stack 130 .

In one embodiment, as shown in FIG. 2 , the flow battery system may further include a second liquid storage chamber 140 located underground and separated from the first liquid storage chamber 110 , and the second liquid storage tank 150 is provided in the first liquid storage chamber 140 . in the second liquid storage chamber 140 .

For the specific arrangement of the second liquid storage chamber 140 and the second liquid storage tank 150 , reference may be made to the first liquid storage chamber 110 and the first liquid storage tank 120 , which will not be repeated here.

In another embodiment, the first liquid storage tank 120 and the second liquid storage tank 150 may both be placed in the first liquid storage chamber 110. In this case, the first liquid storage chamber 110 may be set relatively large, To accommodate two liquid storage tanks at the same time, making the flow battery system simpler.

In a specific embodiment, the first liquid storage chamber 110 and the second liquid storage chamber 140 may both be holes surrounded by soil, and the first liquid storage chamber 110 and the second liquid storage chamber 140 are two different holes. The physical volume is between 5 cubic meters and 100 cubic meters. After measuring according to the local heat temperature rise curve, the depth range of the hole from the ground 10 to 10 meters is 10 meters to 50 meters, which can meet the temperature of the soil cave between 15 ° C and 35 ° C. between. The diameter of the holes is 1.5 meters, the volume range of the electrolyte solution that can be filled in each hole is designed to be 17000L to 88000L, and the energy density of the electrolyte solution is 30Wh/L, so each hole can store 510KWh-2550KWh electric energy. In this example, the storage capacity of the flow battery can be improved by increasing the number of liquid storage chambers to store more electrolyte solution.

The setting method of the first liquid storage chamber 110 and the second liquid storage chamber 140 when they are rock caverns can refer to the soil cavern, which will not be repeated here.

In another specific embodiment, the first liquid storage chamber 110 and the second liquid storage chamber 140 can also be caves, and the inner cavity of the cave can be irregularly shaped. 10 The depth range is 180 meters to 220 meters, which can meet the cave temperature of about 50 ℃. The physical volume of the cave can be 5 cubic meters to 100,000 cubic meters, the height is 80 meters, and the maximum width is 60 meters. The inner layer of the cave is coated with an anti-corrosion layer, and the anti-corrosion layer is made of epoxy anti-corrosion paint to prevent the electrolyte solution in the first liquid storage tank 120 and the second liquid storage tank 150 from leaking and corroding the rock wall.

The materials of the first liquid storage tank 120 and the second liquid storage tank 150 are shaped PTFE or PP or PVC material. The first liquid storage tank 120 and the second liquid storage tank 150 may be formed by splicing sheet plastics, so as to facilitate the generation of large liquid storage tanks.

The electric stack 130 is placed in the underground space, and the electric stack 130 is located between the first liquid storage tank 120 and the second liquid storage tank 150 . This arrangement can effectively reduce the pump work and improve the energy storage efficiency of the system.

Below, the charging and discharging process of the flow battery system is briefly introduced.

As shown in FIG. 2 and FIG. 3 , when the flow battery system is charging, the high-voltage alternating current of the external power grid 40 or the electricity generated by the new energy power plant (wind power plant or solar power plant) is converted into direct current with a stable voltage through the power conversion system 160, For example, the electricity generated by the wind power generation system 20 or the solar power generation system 30 is converted into DC power with a stable voltage through the power conversion system 160 , and then transmitted to the positive and negative terminals of the stack 130 through the power cable 131 . Specifically, after the control system 170 receives the charging instruction signal, it controls the power conversion system 160 to pass the converted direct current to the stack 130, and the control system 170 controls the rotor of the circulating pump 138a to rotate, and obtains the rotational speed of the rotor of the circulating pump 138a. , to perform speed feedback control, so that the positive and negative electrolyte solutions enter the stack 130 through the pipeline at a stable and controllable flow rate to participate in the charging chemical reaction of the flow battery.

For the convenience of reading the figure clearly, the power cables between the various devices are omitted in FIG. 3 .

Taking an all-vanadium redox flow battery as an example, during charging, the stack 130 oxidizes tetravalent vanadium ions in the positive electrolyte solution to pentavalent vanadium ions, and reduces trivalent vanadium ions in the negative electrode electrolyte solution to divalent vanadium ions. The specific chemical equation of the charging process is:

positive electrode:

Negative: V ³⁺ +e ^- → V ²⁺

Overall response:

The State of Charge (SOC) of a battery refers to the percentage of the current remaining capacity of the battery to the rated capacity when the battery is fully charged, and can be expressed as:

The value of SOC ranges from 0 to 1. The larger the SOC, the more power the battery stores.

The first liquid storage tank 120 and the second liquid storage tank 150 can be placed with an electric quantity detection sensor 180 , a temperature sensor, a concentration detector, a pressure sensor, etc. The device may be communicatively connected to the control system 170 through a communication cable.

The above-mentioned electric quantity detection sensor 180 may be a Hall current sensor or other components capable of monitoring electric quantity.

The control system 170 of the flow battery system obtains the data of the power monitoring element, and estimates the SOC of the flow battery to determine whether it is fully charged. When it is determined that it is fully charged, it controls the circulating pump 138a to stop working to prevent overcharging.

After the control system 170 obtains the discharge command, it generates a control signal and controls the operating speed of the circulation pump 138 a, thereby controlling the flow rate of the electrolyte solution flowing into the stack 130 . The electrolyte solution flowing into the stack 130 occurs at the bipolar plate 134 of the stack 130 In the redox reaction, electrons are conducted in the bipolar plate 134 and flow from the negative electrode to the positive electrode after passing through the current collector plate 135, the H ⁺ ions of the positive electrode flow to the negative electrode through the ion exchange membrane 137c, and the formed current is transmitted to the power conversion system through the energized cable 131 160, which is converted into a high-voltage alternating current of the same frequency that is compatible with the external power grid 40 for use by the user terminal, and finally realizes peak-shaving and valley-filling of the power grid and new energy storage. The specific chemical equation of the discharge process is as follows:

positive electrode:

Negative: V ₂ -→V ₃ ⁺ +e ^-

Overall response:

When SOC=0, the control system 170 controls the circulating pump 138a to stop working, and sends out a prompt message that the discharge is finished.

Taking the iron-chromium flow battery as an example, when charging, the stack 130 causes the divalent Fe ions in the positive electrolyte solution to lose electrons and be oxidized to trivalent Fe ions, so that the trivalent chromium ions in the negative electrolyte solution gain electrons and reduce to 2 Chromium ions. The specific chemical equation of the charging process is:

Positive electrode: Fe ²⁺ → Fe ³⁺ +e

Negative electrode: Cr ³⁺ +e→Cr ²⁺

Overall reaction: Fe ²⁺ +Cr ³⁺ →Fe ³⁺ +Cr ²⁺

The specific chemical equation of the discharge process is as follows:

Positive electrode: Fe ³⁺ +e→Fe ²⁺

Negative electrode: Cr ²⁺ →Cr ³⁺ +e

Overall reaction: Fe ³⁺ +Cr ²⁺ →Fe ²⁺ +Cr ³⁺

It should be understood that the above is only to help those skilled in the art to better understand the embodiments of the present application, but is not intended to limit the scope of the embodiments of the present application. Based on the above-mentioned examples, those skilled in the art can obviously make various equivalent modifications or changes, or combinations of any two or any of the above-mentioned embodiments. Such modifications, changes or combined solutions also fall within the scope of the embodiments of the present application.

It should also be understood that the above description of the embodiments of the present application focuses on emphasizing the differences between the various embodiments, and the unmentioned same or similar points can be referred to each other, and are not repeated here for brevity.

It should also be understood that the manners, situations, categories, and divisions of the embodiments in the embodiments of the present application are only for the convenience of description, and should not constitute a special limitation, and the various manners, categories, situations, and features in the embodiments are not contradictory. can be combined.

It should also be understood that, in the various embodiments of the present application, if there is no special description or logical conflict, the terms and/or descriptions between different embodiments are consistent and can be referred to each other, and the technical features in different embodiments New embodiments can be combined according to their inherent logical relationships.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art who is familiar with the technical scope disclosed in the present application can easily think of changes or substitutions. Covered within the scope of protection of this application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (10)

1. A liquid flow battery system based on underground space, characterized in that, comprising: a first liquid storage tank (120), the first liquid storage tank (120) is arranged underground and is used for storing the first electrolyte solution; The second liquid storage tank (150) is used for storing a second electrolyte solution, and the second electrolyte solution and the first electrolyte solution are respectively used for electrochemical reactions with opposite polarities; The electric stack (130) is communicated with the first liquid storage tank (120) and the second liquid storage tank (150) respectively. 2. The flow battery system according to claim 1, wherein the flow battery system further comprises: A first liquid storage chamber (110), the first liquid storage chamber (110) is a space provided underground, and the first liquid storage tank (120) is provided in the first liquid storage chamber (110). 3. The flow battery system according to claim 2, characterized in that, there is a manual detection space (113) between the first liquid storage tank (120) and the inner wall of the first liquid storage chamber (110). ), a first artificial detection channel (114) is provided between the artificial detection space (113) and the ground. 4. The flow battery system according to claim 2, wherein the flow battery system further comprises a control system, a liquid leakage detection device is provided at the bottom of the first liquid storage chamber (110), and the The liquid leakage detection device is located outside the first liquid storage tank (120) and is connected in communication with the control system (170). 5. The flow battery system according to claim 2, wherein an anti-corrosion layer is provided on the inner wall of the first liquid storage chamber (110). 6. The flow battery system according to claim 1, wherein a liquid conveying channel (111) is provided between the first liquid storage tank (120) and the ground. 7. The flow battery system according to any one of claims 1 to 6, wherein the electric stack (130) is arranged in an underground space, and the electric stack (130) is electrically connected with a Power cable (131) to the ground. 8 . The flow battery system according to claim 7 , wherein a second manual detection channel ( 132 ) is provided between the underground space where the electric stack ( 130 ) is located and the ground, and the power cable (131) is located in the second manual detection channel (132). 9 . The flow battery system according to claim 8 , wherein an air flow channel is provided between the underground space where the electric stack ( 130 ) is located and the ground, and the air flow channel and the second manual detection Channels (132) are set separately. 10. The flow battery system according to any one of claims 1 to 6, wherein the electric stack (130) is arranged on the ground, and the first liquid storage tank (120) is provided with a liquid outlet The stack (130) is provided with a liquid inlet communicated with the liquid outlet, and the height difference between the liquid outlet and the liquid inlet is not greater than 10 meters.

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