Anti-reflux all-vanadium redox flow electricity storage system

Abstract

The utility model discloses an anti-countercurrent all-vanadium redox flow electricity storage system, which comprises an all-vanadium redox flow electricity storage device, an all-vanadium redox flow electricity storage device, an all-vanadium redox flow electricity storage device and an all-vanadium redox flow electricity storage device, and the anti-reflux device is connected between the all-vanadium redox flow electricity storage device and the transformer in series and is used for controlling the all-vanadium redox flow electricity storage device to be disconnected from the transformer when detecting that the current flows to the transformer. According to the application, the anti-reflux device is arranged, so that the anti-reflux device can be used for accurately detecting whether the current reflux phenomenon occurs in the all-vanadium redox flow electricity storage device or not, and when the current reflux phenomenon occurs, the all-vanadium redox flow electricity storage device is controlled to be disconnected from the transformer in time, so that the damage to the all-vanadium redox flow electricity storage device caused by the reflux phenomenon can be prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, and particularly relates to a vanadium redox flow energy storage system with reverse current prevention. Background Art

[0002] The vanadium redox flow battery is a renewable energy storage technology, which has the advantages of high energy density, long service life, easy expansion and maintenance, etc., and is therefore widely used in fields such as power systems, data centers, and distributed energy.

[0003] However, when the existing vanadium redox flow battery stores energy, when the external grid voltage is greater than the voltage of the energy storage system, a reverse current phenomenon is likely to occur, which will damage the vanadium redox flow battery and the external grid. Summary of the Utility Model

[0004] In view of this, the utility model provides a vanadium redox flow energy storage system with reverse current prevention, mainly aiming to solve the problem that when the existing vanadium redox flow battery stores energy, the reverse current damages the vanadium redox flow battery.

[0005] To solve the above problems, the present application provides a vanadium redox flow energy storage system with reverse current prevention.

[0006] The vanadium redox flow energy storage system is connected to a transformer, and the vanadium redox flow energy storage system includes:

[0007] A vanadium redox flow energy storage device, the input end of which is electrically connected to the output end of the transformer;

[0008] A reverse current prevention device, which is connected in series between the vanadium redox flow energy storage device and the transformer, and is used to control the disconnection of the vanadium redox flow energy storage device from the transformer when it detects that the current of the vanadium redox flow energy storage device flows towards the transformer.

[0009] Optionally, the vanadium redox flow energy storage system with reverse current prevention further includes:

[0010] A first power detection device, which is connected in series between the vanadium redox flow energy storage device and the transformer, and is used to detect the power flowing into the vanadium redox flow energy storage device, obtain a first power value, and send the first power value to the energy management system;

[0011] A second power detection device, which is connected in series between the load and the transformer, and is used to detect the power flowing into the load, obtain a second power value, and then send the second power value to the energy management system;

[0012] The energy management system is electrically connected to the first power detection device, the second power detection device, and the anti-counterflow device, and is configured to determine whether current counterflows occur based on the received first power value and second power value, and send a cut-off signal to the anti-counterflow device when current counterflows occur;

[0013] The anti-counterflow device is further configured to receive the cut-off signal sent by the energy management system and control the disconnection of the all-vanadium redox flow energy storage device from the transformer based on the cut-off signal.

[0014] Optionally, the anti-counterflow device includes:

[0015] A current detection module, which is connected in series between the all-vanadium redox flow energy storage device and the transformer and is electrically connected to the control module, is configured to detect the current flow direction signal of the energy storage system and send the current flow direction signal to the control module;

[0016] The control module is configured to receive the current flow direction signal sent by the current detection module, determine whether current counterflows occur according to the current flow direction signal, and send a control signal to the counterflow blocking module when it is determined that current counterflows occur;

[0017] The counterflow blocking module is controlled and connected to the control module, and is configured to receive the control signal sent by the control module and control the disconnection of the all-vanadium redox flow energy storage device from the transformer based on the control signal

[0018] Optionally, the all-vanadium redox flow energy storage device includes: a bidirectional converter and a battery management system BMS;

[0019] The input end of the bidirectional converter serves as the input end of the all-vanadium redox flow energy storage device, and is electrically connected to the transformer through the anti-counterflow device; the output end is electrically connected to the stack; the communication end is respectively communicatively connected to the battery management system BMS and the energy management system EMS.

[0020] Optionally, the all-vanadium redox flow energy storage device further includes: a positive and negative circulation pump, an auxiliary system;

[0021] The positive and negative circulation pump and the auxiliary system are respectively electrically connected to the input end of the bidirectional converter.

[0022] Optionally, the current detection module includes a current sensor.

[0023] Optionally, the counterflow blocking module includes a smart circuit breaker

[0024] In the present application, a vanadium redox flow energy storage system with anti-counterflow function can accurately detect whether current counterflow occurs in the vanadium redox flow energy storage device by setting an anti-counterflow device. When current counterflow occurs, it can timely control the disconnection between the vanadium redox flow energy storage device and the transformer, thereby preventing damage to the vanadium redox flow energy storage device caused by the counterflow phenomenon.

[0025] The above description is only an overview of the technical solution of the present utility model. In order to understand the technical means of the present utility model more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present utility model more obvious and understandable, the specific embodiments of the present utility model are specifically exemplified below. Brief Description of the Drawings

[0026] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered as limiting the present utility model. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0027] Figure 1 It is a schematic diagram of a vanadium redox flow energy storage system with anti-counterflow function according to an embodiment of the present application. Detailed Description of the Embodiments

[0028] Reference is made herein to the various aspects and features of the present application with reference to the accompanying drawings.

[0029] It should be understood that various modifications can be made to the embodiments applied herein. Therefore, the above description should not be considered as a limitation, but only as an example of the embodiments. Those skilled in the art will think of other modifications within the scope and spirit of the present application.

[0030] The drawings included in the specification and constituting a part of the specification show the embodiments of the present application, and together with the general description of the present application given above and the detailed description of the embodiments given below, are used to explain the principles of the present application.

[0031] These and other features of the present application will become apparent from the following description of the preferred forms of the embodiments given by way of non-limiting example with reference to the accompanying drawings.

[0032] It should also be understood that although the present application has been described with reference to some specific examples, those skilled in the art can surely implement many other equivalent forms of the present application.

[0033] When combined with the accompanying drawings, in view of the following detailed description, the above and other aspects, features and advantages of the present application will become more obvious.

[0034] Specific embodiments of the present application will be described hereinafter with reference to the accompanying drawings; however, it should be understood that the embodiments claimed are merely examples of the present application and can be implemented in various ways. Well-known and / or repetitive functions and structures are not described in detail to avoid obscuring the present application with unnecessary or redundant details. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but are merely a basis and representative basis for the claims to teach those skilled in the art to use the present application in substantially any suitable detailed structure in a variety of ways.

[0035] This specification may use the phrases "in one embodiment", "in another embodiment", "in yet another embodiment", or "in other embodiments", all of which may refer to one or more of the same or different embodiments according to the present application.

[0036] An embodiment of the present application provides a vanadium redox flow energy storage system with reverse current prevention. The vanadium redox flow energy storage system is connected to a transformer, and the vanadium redox flow energy storage system is as Figure 1 shown, including: a vanadium redox flow energy storage device 1 and a reverse current prevention device 2. The input end of the vanadium redox flow energy storage device 1 is electrically connected to the output end of the transformer 3. The reverse current prevention device 2 is connected in series between the vanadium redox flow energy storage device 1 and the transformer 3, and is used to control the disconnection of the vanadium redox flow energy storage device from the transformer when it detects that the current of the vanadium redox flow energy storage device flows towards the transformer. In this embodiment, by setting the reverse current prevention device, it is possible to accurately detect whether a reverse current phenomenon occurs in the vanadium redox flow energy storage device by using the reverse current prevention device, and when a reverse current occurs, timely control the disconnection of the vanadium redox flow energy storage device from the transformer, thereby preventing damage to the vanadium redox flow energy storage device caused by the reverse current phenomenon.

[0037] In this embodiment, the vanadium redox flow energy storage device 1 specifically includes: a bidirectional converter 1-1, positive and negative liquid tanks, an electrolytic stack 1-2, positive and negative circulation pumps 1-3, an auxiliary system 1-4, and a BMS battery management system 1-5. Among them, the input end of the bidirectional converter 1-1 is used as the input end of the vanadium redox flow energy storage device and is electrically connected to the transformer 3 through the reverse current prevention device 2. The output end of the bidirectional converter 1-1 is electrically connected to the electrolytic stack 1-2. The communication end of the bidirectional converter 1-1 is respectively communicatively connected to the BMS battery management system 1-5 and the EMS energy management system 5. Specifically, the bidirectional converter, BMS, and EMS are communicatively connected using an Ethernet port and based on the Modbus-tcp protocol. In this embodiment, the positive and negative circulation pumps 1-3 and the auxiliary system 1-4 are respectively electrically connected to the input end of the bidirectional converter.

[0038] In this embodiment, the backflow prevention device 2 specifically includes: a current detection module, a control module, and a backflow blocking module. The current detection module is connected in series between the all-vanadium redox flow energy storage device and the transformer and is electrically connected to the control module, and is used for detecting the current flow direction signal of the energy storage system and sending the current flow direction signal to the control module. The control module is used for receiving the current flow direction signal sent by the current detection module, determining whether current backflow occurs according to the current flow direction signal, and sending a control signal to the backflow blocking module when it is determined that current backflow occurs. The backflow blocking module is connected to the control module in a controlled manner and is used for receiving the control signal sent by the control module and controlling the disconnection of the all-vanadium redox flow energy storage device and the transformer based on the control signal. Among them, the control module can adopt a programmable logic controller (PLC). The current detection module can be a current sensor. The backflow blocking module can be an intelligent circuit breaker.

[0039] The all-vanadium redox flow energy storage system in this embodiment further includes: a first power detection device 4 and a second power detection device 5. The first power detection device 4 is connected in series between the all-vanadium redox flow energy storage device 1 and the transformer 3. Specifically, the first power detection device 4 is connected in series between the input end of the bidirectional converter 1-1 and the backflow prevention device 2. The first power detection device 4 is used for detecting the power flowing into the all-vanadium redox flow energy storage device, obtaining a first power value, and sending the first power value to the energy management system 6. The second power detection device 5 is connected in series between the load 7 and the transformer 1, that is, connected in series between the load 7 and the backflow prevention device 2, and is used for detecting the power flowing into the load, obtaining a second power value, and then sending the second power value to the energy management system 6. The energy management system 6 is electrically connected to the first power detection device 4, the second power detection device 5, and the backflow prevention device 2, and is used for determining whether current backflow occurs based on the received first power value and second power value, and sending a cut-off signal to the backflow prevention device when current backflows; the backflow prevention device is further used for receiving the cut-off signal sent by the energy management system and controlling the disconnection of the all-vanadium redox flow energy storage device and the transformer based on the cut-off signal. In this embodiment, when the second power value detected by the second power detection device 5 is greater than or equal to the first power value detected by the first power detection device 4, it is determined that the all-vanadium redox flow energy storage device operates normally and no current backflow occurs. On the contrary, when the second power value detected by the second power detection device 5 is less than the first power value detected by the first power detection device 4, that is, when the power flowing into the load is less than the power flowing into the all-vanadium redox flow energy storage device, it indicates that a current backflow phenomenon occurs, and thus the all-vanadium redox flow energy storage device can be controlled to be disconnected from the transformer. In this embodiment, the first power detection device can be a bidirectional power meter. The second power detection device can specifically be a high-precision power meter.

[0040] In this embodiment, by setting up the first power detection device and the second power detection device, it is possible to more accurately predict whether there is a current reverse flow based on the first power value and the second power value. Thus, when it is predicted that a current reverse flow is about to occur, the all-vanadium redox flow energy storage device can be timely controlled to disconnect from the transformer, thereby avoiding the impact of the current reverse flow on the external power grid and preventing damage to the all-vanadium redox flow energy storage device caused by the reverse flow phenomenon.

[0041] In this embodiment, the all-vanadium redox flow battery / all-vanadium redox flow energy storage device is a redox battery with vanadium as the active substance in a circulating liquid state. Its charge and discharge working principles involve electrode reactions and internal electrochemical reactions. During the charging process, the tetravalent vanadium ions (VO2+) in the positive electrode electrolyte are oxidized to pentavalent vanadium ions (VO2+), losing one electron, and at the same time, two hydrogen ions (H+) are generated. While the trivalent vanadium ions (V3+) in the negative electrode electrolyte gain one electron and are reduced to divalent vanadium ions (V2+), consuming one hydrogen ion. At this time, the hydrogen ions migrate from the positive electrode to the negative electrode. During the discharging process, the situation is reversed. The pentavalent vanadium ions (VO2+) in the positive electrode electrolyte gain one electron and are reduced to tetravalent vanadium ions (VO2+), consuming two hydrogen ions at the same time. While the divalent vanadium ions (V2+) in the negative electrode electrolyte lose one electron and are oxidized to trivalent vanadium ions (V3+), generating one hydrogen ion at the same time. At this time, the hydrogen ions migrate from the negative electrode to the positive electrode. The internal electrochemical reaction in the battery is manifested as the migration of hydrogen ions inside, while an electric current is generated in the external circuit, thus converting the chemical energy stored in the solution into electrical energy. Generally speaking, the charge and discharge process of the all-vanadium redox flow battery is a complex process involving changes in the valence state of vanadium ions, electron gain and loss, and hydrogen ion migration. Through these processes, the conversion between chemical energy and electrical energy is achieved.

[0042] During the charging process of the all-vanadium redox flow energy storage device, the positive and negative circulation pumps are started to transfer the electrolyte in the electrolyte tank into the stack to occur the above reactions. At the same time, according to the real-time power of the load during the valley electricity period (charging period), the charging power of the system is adjusted to ensure that the total load reaches the design value during the charging process, reducing the demand electricity cost and improving the economic benefit.

[0043] During the discharging process of the all-vanadium redox flow energy storage device, the discharging is carried out according to the above process. At the same time, the system discharges according to the real-time power of the load, adjusts the discharging power to ensure that the discharging power is not greater than the load power, and on the basis of meeting the load application, no reverse current is generated and there is no impact on the power grid.

[0044] The above embodiments are only exemplary embodiments of the present application and are not used to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present application, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present application.

Claims

1. A backflow-proof all-vanadium liquid flow power storage system, characterized in that: The all-vanadium liquid flow electricity storage system is connected to a transformer, and the all-vanadium liquid flow electricity storage system comprises: The input end of the all-vanadium liquid flow electricity storage device is electrically connected to the output end of the transformer; The anti-backflow device is connected in series between the all-vanadium liquid flow electricity storage device and the transformer, and is used to control the all-vanadium liquid flow electricity storage device to be disconnected from the transformer when it is detected that the current of the all-vanadium liquid flow electricity storage device flows to the transformer.

2. The anti-backflow all-vanadium liquid flow electricity storage system according to claim 1, characterized in that: Also includes: A first electric quantity detection device is connected in series between the all-vanadium liquid flow electricity storage device and the transformer, and is used to detect the electric quantity flowing into the all-vanadium liquid flow electricity storage device, obtain a first electric quantity value, and send the first electric quantity value to the energy management system; A second electric quantity detection device is connected in series between the load and the transformer, and is used to detect the electric quantity flowing into the load, obtain a second electric quantity value, and then send the second electric quantity value to the energy management system; The energy management system is electrically connected to the first power detection device, the second power detection device and the backflow prevention device, and is used to determine whether a current backflow occurs based on the received first power value and the second power value, and send a cut-off signal to the backflow prevention device when the current backflows; The backflow prevention device is also used to receive a cut-off signal sent by the energy management system, and control the all-vanadium liquid flow power storage device to be disconnected from the transformer based on the cut-off signal.

3. The anti-backflow all-vanadium liquid flow electricity storage system according to claim 1 or 2, characterized in that: The anti-backflow device comprises: A current detection module is connected in series between the all-vanadium liquid flow energy storage device and the transformer and is electrically connected to the control module, and is used to detect a current flow direction signal of the energy storage system and send the current flow direction signal to the control module; The control module is used to receive the current flow direction signal sent by the current detection module, determine whether current reverse flow occurs according to the current flow direction signal, and send a control signal to the reverse flow blocking module when it is determined that current reverse flow occurs; The backflow blocking module is controllably connected to the control module, and is used to receive a control signal sent by the control module, and control the all-vanadium liquid flow power storage device to be disconnected from the transformer based on the control signal.

4. The anti-backflow all-vanadium liquid flow electricity storage system according to claim 1, characterized in that: The all-vanadium liquid flow power storage device comprises: a bidirectional converter and a battery management system BMS; The bidirectional converter has an input end as the input end of the all-vanadium liquid flow power storage device, which is electrically connected to the transformer through an anti-backflow device; an output end is electrically connected to the battery stack; and a communication end is respectively connected to the battery management system BMS and the energy management system EMS.

5. The anti-backflow all-vanadium liquid flow electricity storage system according to claim 4, characterized in that: The all-vanadium liquid flow electricity storage device also includes: positive and negative electrode circulation pumps and an auxiliary system; The positive and negative electrode circulation pumps and the auxiliary system are electrically connected to the input ends of the bidirectional converter respectively.

6. The anti-backflow all-vanadium liquid flow electricity storage system according to claim 4, characterized in that: The current detection module includes a current sensor.

7. The anti-backflow all-vanadium liquid flow electricity storage system according to claim 1, characterized in that: The reverse flow blocking module includes an intelligent circuit breaker.

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