Bypass current suppression device and flow battery

Abstract

The present invention provides a bypass current suppression device and a liquid flow battery. The bypass current suppression device includes an infusion structure, an opening and closing piece, and a magnetic piece. The infusion structure is provided with an inlet and an outlet. The infusion structure is provided with a first chamber connected to the inlet, a second chamber connected to the outlet, and a drainage hole connected to the first chamber and the second chamber. The opening and closing piece is movably arranged in the second chamber, and the magnetic piece is arranged on the infusion structure. The opening and closing piece can close the drainage hole under the action of the magnetic force provided by the magnetic piece, so that the electrolyte cannot flow into the second chamber of the infusion structure through the drainage hole inside the infusion structure. The opening and closing piece can open the drainage hole under the action of the pressure of the electrolyte in the first chamber, thereby realizing the intermittent flow of the electrolyte between the battery stacks, cutting off the bypass current channel between the battery stacks, and effectively suppressing the generation of bypass current between the battery stacks.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage batteries, and in particular, relates to a bypass current suppression device and a liquid flow battery. Background Art

[0002] As a new type of battery technology, flow batteries have gained widespread attention for their advantages such as high efficiency, safety and reliability, long cycle life, and flexible structural design. Since the electrolytes of each group of batteries in the flow battery stack are connected, and there is a certain potential difference between them due to the difference in the body or the uneven distribution of the electrolyte, bypass current will inevitably be generated. Bypass current exists not only between the groups of batteries in the stack, but also between different stacks connected by electrolyte, and it exists both when the system is running and in standby mode, thus causing a significant decrease in the coulombic efficiency and energy efficiency of the flow battery. Flow batteries are often used for large-scale energy storage. Usually, a single stack contains dozens of single batteries connected in series, and a single system also requires several or even dozens of stacks connected in series. Therefore, the negative impact of bypass current on the performance of flow batteries cannot be ignored.

[0003] At present, in order to reduce the impact of bypass current between different battery stacks, the bypass resistance is increased by increasing the length of the pipeline outside the battery stack and reducing the cross-sectional area of ​​the pipeline, thereby reducing the bypass current. However, the increase in pipeline length and the reduction in pipeline cross-sectional area will not only require an increase in pump power, but also reduce the efficiency of the flow battery, increase pipeline costs, and significantly increase the volume occupied by the system. Summary of the invention

[0004] Based on the above problems existing in the prior art, an embodiment of the present invention aims to provide a bypass current suppression device to solve the problem in the prior art that bypass current exists between different stacks of liquid flow batteries, resulting in reduced coulombic efficiency and energy efficiency of the liquid flow batteries.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a bypass current suppression device, including an infusion structure, an opening and closing piece and a magnetic piece, the infusion structure is provided with an inlet and an outlet, the infusion structure is provided with a first chamber connected to the inlet, a second chamber connected to the outlet, and a drainage hole connecting the first chamber and the second chamber, the opening and closing piece is movably arranged in the second chamber, and the magnetic piece is arranged on the infusion structure; the opening and closing piece can close the drainage hole under the action of the magnetic force provided by the magnetic piece, so that the first chamber is not connected to the second chamber; the opening and closing piece can open the drainage hole under the action of the pressure of the electrolyte in the first chamber, so that the first chamber is connected to the second chamber.

[0006] Furthermore, the infusion structure includes a tube shell and an annular tube neck arranged inside the tube shell, the annular tube neck divides the inside of the tube shell into the first chamber and the second chamber, the annular hole of the annular tube neck constitutes the drainage hole, one end of the tube shell is provided with the liquid inlet, and the other end of the tube shell is provided with the liquid outlet.

[0007] Furthermore, the opening and closing member includes a metal flap hinged on the annular tube neck.

[0008] Furthermore, an insulating layer is provided on at least one side surface of the opening and closing member.

[0009] Furthermore, the bypass current suppression device also includes a buffer component for limiting the flipping angle of the opening and closing member, and the buffer component includes a base arranged in the second chamber and an elastic member arranged on the base.

[0010] Furthermore, a step structure is provided in the annular hole of the annular tube neck, the magnetic component is embedded in the annular hole of the annular tube neck, and the magnetic component is supported on the end surface of the step structure away from the opening and closing component.

[0011] Furthermore, an annular pad is provided on the end surface of the step structure facing the opening and closing member.

[0012] Furthermore, the magnetic member is a first magnet, and the opening and closing member is provided with a second magnet.

[0013] Further, the magnetic member is an electromagnet, and the bypass current suppression device further includes a current regulating device for regulating the current intensity passing through the electromagnet and a controller for controlling the current intensity of the current regulating device according to the electrolyte flow rate, and the current intensity I passing through the electromagnet satisfies the following formula:

[0014] I = (kQδ / N)*(ρs' / (μ0S 3 )) 1 / 2 ;

[0015] Where, I is the current intensity passing through the electromagnet, in A; N is the number of turns of the electromagnet coil;

[0016] μ0 is the vacuum magnetic permeability, and its value is 4π*10 -7 kg·m / (s 2 A 2 );s' is the magnetic circuit cross-sectional area of ​​the electromagnet, unit is m 2 ; δ is the air gap length, in m; k is the magnetic enhancement coefficient, which is 1.5~10; Q is the average flow rate of electrolyte per unit time (tT, t) in the tube shell, in m 3 / s, where t is the current time, T is the preset time period, and ρ is the electrolyte density in kg / m 3 ; S is the force area of ​​the opening and closing member facing the first cavity side squeezed by the electrolyte, the unit is m 2 .

[0017] Another object of an embodiment of the present invention is to provide a liquid flow battery to solve the problem in the prior art that there is a bypass current between different battery stacks of the liquid flow battery, resulting in a decrease in the coulombic efficiency and energy efficiency of the liquid flow battery.

[0018] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a liquid flow battery, including the bypass current suppression device provided by any of the above-mentioned embodiments.

[0019] Compared with the prior art, the one or more technical solutions in the embodiments of the present invention have at least one of the following beneficial effects:

[0020] In the bypass current suppression device and liquid flow battery in the embodiments of the present invention, after the electrolyte enters the first chamber of the infusion structure through the inlet of the infusion structure, the opening and closing piece can close the drainage hole under the action of the magnetic force provided by the magnetic piece, so that the electrolyte cannot flow into the second chamber of the infusion structure through the drainage hole inside the infusion structure. As the electrolyte continues to accumulate in the first chamber, when the pressure of the electrolyte in the first chamber on the opening and closing piece is greater than the magnetic force of the magnetic piece on the opening and closing piece, the opening and closing piece can open the drainage hole under the action of the pressure of the electrolyte in the first chamber. At this time, the electrolyte in the first chamber can quickly flow into the second chamber through the drainage hole to realize the circulation of the electrolyte. In this process, the pressure of the electrolyte in the first chamber on the opening and closing piece gradually decreases until the opening and closing piece can re-close the drainage hole under the action of the magnetic force provided by the magnetic piece, thereby blocking the circulation of the electrolyte between the first chamber and the second chamber. Such a cycle, while ensuring the total flow supply of electrolyte, realizes the intermittent flow of electrolyte between battery stacks, cuts off the bypass current channel between battery stacks, and effectively suppresses the generation of bypass current between battery stacks. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 A schematic diagram of the structure of a bypass current suppression device provided in Embodiment 1 of the present invention;

[0023] Figure 2A schematic side view of the bypass current suppression device provided in the first embodiment of the present invention;

[0024] Figure 3 A schematic cross-sectional view of the bypass current suppression device provided in Embodiment 1 of the present invention;

[0025] Figure 4 An exploded view of a bypass current suppression device provided in Embodiment 1 of the present invention;

[0026] Figure 5 A schematic cross-sectional view of a bypass current suppression device provided in Embodiment 2 of the present invention;

[0027] Figure 6 An exploded view of a bypass current suppression device provided in Embodiment 2 of the present invention;

[0028] Figure 7 A schematic diagram of the bypass current suppression device provided in an embodiment of the present invention being connected to a fuel cell stack.

[0029] Among them, the reference numerals in the figure are:

[0030] Infusion structure; 11-tube housing; 12-annular tube neck; 13-first chamber; 14-second chamber; 15-liquid discharge hole; 16-liquid inlet; 17-liquid outlet; 18-opening; 2-opening and closing member; 3-magnetic member; 4-hinged member;

[0031] 5-buffer assembly; 51-base; 52-elastic member;

[0032] 6-ring pad; 7-wire; 8-second magnet; 9-step structure;

[0033] 10-bypass current suppression device; 20-cell stack; 30-positive electrode liquid storage tank; 40-negative electrode liquid storage tank. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] It should be noted that when an element is referred to as "connected to" or "set on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly specified and specifically defined. In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0036] Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, when the phrases "in one embodiment," "in some embodiments," or "in some of these embodiments" appear in various places throughout the specification, not all references are to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner.

[0037] Embodiment 1

[0038] Please also read Figures 1 to 4, the bypass current suppression device provided by the first embodiment of the present invention is now described. The bypass current suppression device provided by the first embodiment of the present invention includes an infusion structure 1, an opening and closing member 2 and a magnetic member 3. The infusion structure 1 is provided with an inlet 16 and an outlet 17. The infusion structure 1 is provided with a first chamber 13 connected to the inlet 16, a second chamber 14 connected to the outlet 17, and a drainage hole 15 connecting the first chamber 13 and the second chamber 14. The opening and closing member 2 is movably arranged in the second chamber 14, and the magnetic member 3 is arranged on the infusion structure 1. The opening and closing member 2 can close the drainage hole 15 under the action of the magnetic force provided by the magnetic member 3, so that the first chamber 13 and the second chamber 14 are not connected. When the bypass current suppression device is installed in the liquid circuit of the liquid flow battery, after the electrolyte enters the first chamber 13 of the liquid infusion structure 1 through the liquid inlet 16 of the liquid infusion structure 1, due to the blocking effect of the opening and closing member 2, the electrolyte cannot flow into the second chamber 14 of the liquid infusion structure 1 through the drainage hole 15 inside the liquid infusion structure 1, and the electrolyte will continue to accumulate in the first chamber 13 until the force for opening the opening and closing member 2 (the pressure of the electrolyte in the first chamber 13 on the opening and closing member 2) is greater than the force for closing the opening and closing member 2 (the pressure of the magnetic member 3 on the opening and closing member 2). ), the opening and closing member 2 can open the drainage hole 15 under the pressure of the electrolyte in the first chamber 13, so that the first chamber 13 is connected to the second chamber 14, and the electrolyte in the first chamber 13 can quickly flow into the second chamber 14 through the drainage hole 15, and flow out from the outlet 17 of the infusion structure 1. In this process, the pressure of the electrolyte in the first chamber 13 on the opening and closing member 2 is gradually reduced until the opening and closing member 2 can reclose the drainage hole 15 under the magnetic force provided by the magnetic member 3, so that the first chamber 13 is not connected to the second chamber 14. In this way, on the basis of ensuring the total flow supply of the electrolyte, the intermittent flow of the electrolyte between the battery stacks is realized, the bypass current channel between the battery stacks is cut off, thereby interrupting the electrolyte flow network between the battery stacks, and effectively suppressing the generation of bypass current between the battery stacks. In the later stage of charging and discharging, in order to eliminate concentration polarization and improve the performance of the battery stack, the electrolyte supply can be increased.

[0039] It should be noted that Figure 3 The bypass current suppression device is shown as being installed horizontally. In fact, the bypass current suppression device can also be installed vertically or obliquely. In addition to the pressure of the electrolyte in the first chamber 13 on the opening and closing member 2 and the magnetic force of the magnetic member 3 on the opening and closing member 2, there may be other forces that affect the opening and closing of the opening and closing member 2, such as the gravity of the opening and closing member 2, but the opening and closing principles of the opening and closing member 2 are similar. As the electrolyte continues to accumulate in the first chamber 13, the force used to open the opening and closing member 2 will increase until it is greater than the force used to close the opening and closing member 2 and open the opening and closing member 2, and then the opening and closing member 2 will close again to achieve intermittent flow of the electrolyte.

[0040] In addition, the bypass current suppression device provided in the embodiment of the present invention utilizes the change in electrolyte fluid pressure in the first chamber 13 to directly act on the opening and closing member 2. In addition to being able to control the intermittent delivery of the electrolyte, it can also enhance the sensitivity to the electrolyte flow rate and pressure, and can effectively avoid the water hammer effect.

[0041] Compared with the prior art, the bypass current suppression device provided by the embodiment of the present invention is that after the electrolyte enters the first chamber 13 of the infusion structure 1 through the liquid inlet 16 of the infusion structure 1, the opening and closing member 2 can close the drainage hole 15 under the action of the magnetic force provided by the magnetic member 3, so that the electrolyte cannot flow into the second chamber 14 of the infusion structure 1 through the drainage hole 15 inside the infusion structure 1. As the electrolyte continues to accumulate in the first chamber 13, when the pressure of the electrolyte in the first chamber 13 on the opening and closing member 2 is greater than that of the magnetic member 3, the electrolyte in the first chamber 13 is increased. When the magnetic force of the magnetic part 3 on the opening and closing part 2 is exerted, the opening and closing part 2 can open the drainage hole 15 under the pressure of the electrolyte in the first chamber 13, and the electrolyte in the first chamber 13 can quickly flow into the second chamber 14 through the drainage hole 15 to realize the circulation of the electrolyte. In this process, the pressure of the electrolyte in the first chamber 13 on the opening and closing part 2 is gradually reduced until the opening and closing part 2 can reclose the drainage hole 15 under the magnetic force provided by the magnetic part 3, blocking the circulation of the electrolyte between the first chamber 13 and the second chamber 14. In this way, on the basis of ensuring the total flow supply of the electrolyte, the intermittent flow of the electrolyte between the battery stacks is realized, the bypass current channel between the battery stacks is cut off, and the generation of bypass current between the battery stacks is effectively suppressed.

[0042] Please refer to Figure 1 , Figure 2 and Figure 3 In some embodiments, the infusion structure 1 includes a tube housing 11 and an annular tube neck 12 disposed inside the tube housing 11. The annular tube neck 12 separates the inside of the tube housing 11 into a first chamber 13 and a second chamber 14. The annular tube neck 12 forms a drainage hole 15. One end of the tube housing 11 is provided with a liquid inlet 16, and the other end of the tube housing 11 is provided with a liquid outlet 17. In this embodiment, by providing the annular tube neck 12 at the central position inside the tube housing 11, the annular tube neck 12 can be integrally formed with the tube housing 11. The inner diameter of the cross section of the annular tube neck 12 is smaller than the cross section diameter of the tube housing 11, and the inner diameter of the cross section of the annular tube neck 12 is 30-90% of the inner diameter of the cross section of the tube housing 11. The tube housing 11 and the annular tube neck 12 can be made of, but not limited to, corrosion-resistant metal or hard plastic with surface insulation treatment. Preferably, the tube housing 11 and the annular tube neck 12 can be PVC plastic parts.

[0043] Please refer to Figure 2 , Figure 3 and Figure 4In some embodiments, when the magnetic member 3 is an electromagnet, the opening and closing member 2 includes a metal flap made of a ferromagnetic metal material, and the metal flap is hinged on the annular tube neck 12. Specifically, the metal flap can be connected to the upper right side of the annular tube neck 12 through a hinge 4 such as a loose leaf or a hinge. When the electrolyte is in a static state, due to the magnetic force of the annular electromagnet and the metal flap, the metal flap is in a vertical state and closes the drainage hole 15, so that the first chamber 13 and the second chamber 14 are not connected. When the flow battery starts to work, the electrolyte flows into the first chamber 13 from the liquid inlet 16, but due to the magnetic force, the metal flap is still in a vertical state, and the electrolyte cannot pass through the drainage hole 15 between the first chamber 13 and the second chamber 14, and continuously accumulates on the side of the metal flap facing the first chamber 13. As the pump works for a longer time, the electrolyte accumulated on the side of the metal flap facing the first chamber 13 increases, and the pressure of the electrolyte in the first chamber 13 on the metal flap increases. When the pressure of the electrolyte in the first chamber 13 on the metal flap is greater than the magnetic force, the metal flap suddenly opens, and the electrolyte accumulated in the first chamber 13 quickly flows into the second chamber 14 through the drainage hole 15, and then the pressure of the metal flap on the side facing the first chamber 13 decreases. At the same time, the opened metal flap is closed again by the magnetic force of the electromagnet and its own gravity. In this cycle, while ensuring the total flow supply of the electrolyte, the bypass current channel between the battery stacks is cut off, greatly reducing the bypass current.

[0044] In some of the embodiments, the metal flap and hinge are made of corrosion-resistant materials or have their surfaces treated with corrosion-resistant materials to prevent the metal flap and hinge from being corroded by the electrolyte.

[0045] In some of the embodiments, an insulating layer is provided on at least one side of the metal flap, that is, the insulating layer can be provided on the side of the metal flap facing the first chamber 13, the insulating layer can also be provided on the side of the metal flap away from the first chamber 13, and the insulating layer can also be provided on both sides of the metal flap to avoid the bypass current suppression failure caused by the charge passing through the metal flap when there is electrolyte on both sides of the metal flap.

[0046] Please refer to Figure 2 , Figure 3 and Figure 4In some embodiments, the bypass current suppression device further includes a buffer assembly 5 for limiting the flip angle of the metal flap, the buffer assembly 5 includes a base 51 disposed in the second chamber 14 and an elastic member 52 disposed on the base 51, and the distance between the center of the base 51 and the conical spring and the right side of the annular tube neck 12 is less than the diameter of the metal flap. It should be noted that the elastic member 52 may be, but is not limited to, a conical spring made of corrosion-resistant and non-magnetic 316 stainless steel, and the base 51 may be made of, but is not limited to, corrosion-resistant metal or hard plastic. Preferably, the base 51 may be, but is not limited to, PVC plastic. When the pressure of the electrolyte in the first chamber 13 pushes the metal flap to flip and open the drain hole 15, the elastic member 52 plays a buffering and limiting role on the metal flap, so that the elastic member 52 can limit the opening angle of the metal flap. At the same time, the opened metal flap is reclosed by the elastic force of the conical spring, the magnetic force of the electromagnet, and the gravity of the metal flap itself. In this way, the bypass current channel between the battery stacks is cut off while the total flow of the electrolyte is ensured, thereby significantly reducing the bypass current. In another embodiment, the elastic member 52 may be omitted, and the opening angle of the metal flap may be limited directly by the base 51.

[0047] Please refer to Figure 3 In some embodiments, a step structure 9 is provided in the annular hole of the annular tube neck 12, and the magnetic member 3 is annular in structure. The magnetic member 3 is embedded in the annular hole of the annular tube neck 12, and the magnetic member 3 is supported on the end surface of the step structure 9 facing away from the closing member 2, and the axial length of the annular tube neck 12 is greater than the axial length of the annular magnetic member 3. When the pressure of the electrolyte in the first chamber 13 on the opening and closing member 2 is less than the magnetic force of the magnetic member 3 on the opening and closing member 2, the metal flap is accommodated in the step structure inside the annular tube neck 12 under the magnetic force of the magnetic member 3, which can enhance the stability of the metal flap, so that the metal flap has a good sealing effect on the drainage hole 15. It should be noted that the magnetic part 3 is a first magnet or electromagnet with an annular structure, that is, the first magnet or electromagnet is annular, and the annular first magnet or the annular electromagnet is embedded in the annular hole of the annular tube neck 12, and the outer peripheral surface of the annular first magnet or the annular electromagnet is sealed and connected to the inner wall of the annular hole of the annular tube neck 12, and the surface of the annular first magnet or the annular electromagnet is provided with a waterproof layer, or the annular magnet or the annular first electromagnet is provided with a waterproof cover made of corrosion-resistant material.

[0048] Please refer to Figure 3In some embodiments, an annular pad 6 is provided on the end surface of the step structure 9 facing the metal flap, the sum of the thickness of the annular magnetic member 3, the annular pad 6 and the metal flap is slightly less than the axial length of the annular tube neck 12, and the sum of the thickness of the annular magnetic member 3, the annular pad 6 and the metal flap is 10-50 mm, the thickness of the annular pad 6 is 0.1-5 mm, and the thickness of the metal flap is 0.1-10 mm. The annular pad 6 can be a fluororubber pad, which is glued and fixed to the annular tube neck 12 and / or the step structure 9.

[0049] In the later stage of charge and discharge, in order to eliminate concentration polarization and improve the performance of the battery stack, the electrolyte supply can be increased. During use, the flow rate of the pump will be adjusted according to the battery charging state. When the magnetic part 3 is an electromagnet, the bypass current suppression device also includes a current regulating device for adjusting the current intensity passing through the electromagnet and a controller for controlling the current intensity of the current regulating device according to the electrolyte flow rate, so as to ensure that the above effect can be achieved at different flow rates. Among them, the current intensity I passing through the electromagnet satisfies the following formula:

[0050] I = (kQδ / N)*(ρs' / (μ0S 3 )) 1 / 2 ;

[0051] Where, I is the current intensity passing through the electromagnet, in A; N is the number of turns of the electromagnet coil;

[0052] μ0 is the vacuum magnetic permeability, and its value is 4π*10 -7 kg·m / (s 2 A 2 );s' is the magnetic circuit cross-sectional area of ​​the electromagnet, unit is m 2 ; δ is the air gap length, in m; k is the magnetic enhancement coefficient, which is 1.5~10; Q is the average flow rate of the electrolyte per unit time (tT, t) in the tube shell 11, in m 3 / s, where t is the current moment, T is the preset time period, and ρ is the electrolyte density in kg / m 3 ; S is the force area of ​​the opening and closing member facing the first cavity side squeezed by the electrolyte, the unit is m 2 .

[0053] Please refer to Figure 3 and Figure 4, the wire 7 of the electromagnet extends through the opening 18 of the annular tube neck 12 and can be connected to any external power supply with adjustable current. The current intensity passing through the electromagnet is controlled by the controller, so that the magnetic force of the electromagnet can be changed by adjusting the current of the electromagnet, thereby flexibly adapting to changes in the electrolyte flow rate. When the electrolyte flow rate becomes larger, it is necessary to increase the current passed into the electromagnet to increase the magnetic force and ensure that the metal flap can be intermittently closed under the magnetic force of the electromagnet. For example, in the early stage of charging, the flow rate of the electrolyte is small, and a relatively small current is passed into the electromagnet. In the later stage of charging and discharging, while increasing the supply of electrolyte, the current passed into the electromagnet is increased: for example, when charging 0~80% SOC, the electrolyte flow rate is 0.02m 3 / s, the current is 0.5A; when charging 80%~100%, the electrolyte flow rate is 0.025m 3 / s, the current is 0.625A.

[0054] Embodiment 2

[0055] Please refer to Figure 5 and Figure 6 , the difference between the second embodiment and the first embodiment is that, if there is no need to adjust the electrolyte flow rate during the charging and discharging process, the magnetic part 3 can use a first magnet, and install a second magnet 8 with a polarity opposite to that of the first magnet on the opening and closing part 2. At this time, the magnitude of the magnetic force is determined by the thickness of the first magnet and the second magnet 8. Preferably, the first magnet is an annular magnet with a thickness of 6 mm; the second magnet is a circular magnet with a thickness of 3 mm. It should be noted that the first magnet and the second magnet 8 can be corrosion-resistant high-magnetic magnets, such as ultra-high-performance neodymium iron boron magnets; the opening and closing part 2 can be a metal flap made of metal material.

[0056] The embodiment of the present invention further provides a liquid flow battery, which includes the bypass current suppression device provided in any of the above embodiments. Since the liquid flow battery has all the technical features of the bypass current suppression device provided in any of the above embodiments, it has the same technical effect as the bypass current suppression device.

[0057] The following is a related performance test and analysis of the bypass current suppression device provided by the embodiment of the present invention in combination with specific embodiments.

[0058] Experimental Example 1

[0059] For a battery stack 20 with five parallel flow channels equipped with a bypass current suppression device 10, the number of battery cells in a single battery stack is 80, and the electrode area is 4000 cm 2 , output power 62kw, bypass current suppression device is installed on the liquid inlet and outlet pipes of each battery stack, using Figure 7The bypass current suppression device is connected to the battery stack as shown, in which the positive electrode storage tank 30 and the negative electrode storage tank 40 provide electrolyte, and the magnetic part 3 of the bypass current suppression device uses an ultra-high performance Ru-Fe-B magnet to ensure that the installation direction is consistent with the electrolyte flow direction (that is, the opening and closing part 2 is located downstream). The intermittent flow of electrolyte in the flow channel outside the battery stack is achieved, thereby blocking the bypass current network outside the liquid flow battery stack and eliminating the bypass current between the liquid flow battery stacks. An equivalent circuit model is established based on Ohm's law and Kirchhoff's law, and its coulomb efficiency is 95% through simulation.

[0060] Experimental Example 2

[0061] For a battery stack 20 with 10 parallel flow channels equipped with a bypass current suppression device 10, the number of battery cells in a single battery stack is 80, and the electrode area is 4000 cm 2 , output power 62kw, bypass current suppression device is installed on the liquid inlet and outlet pipes of each battery stack, using Figure 7 The bypass current suppression device is connected to the battery stack as shown, in which the positive electrode storage tank 30 and the negative electrode storage tank 40 provide electrolyte, and the magnetic part 3 of the bypass current suppression device uses an ultra-high performance Ru-Fe-B magnet to ensure that the installation direction is consistent with the electrolyte flow direction (that is, the opening and closing part 2 is located downstream). The intermittent flow of electrolyte in the flow channel outside the battery stack is achieved, thereby blocking the bypass current network outside the liquid flow battery stack and eliminating the bypass current between the liquid flow battery stacks. An equivalent circuit model is established based on Ohm's law and Kirchhoff's law, and its coulomb efficiency is 94% through simulation.

[0062] Comparative Example 1

[0063] For a battery stack 20 with five parallel flow channels without the bypass current suppression device 10 installed, the number of battery cells in a single battery stack is 80 and the electrode area is 4000 cm 2 , output power 62kw. Based on Ohm's law and Kirchhoff's law, an equivalent circuit model was established, and the coulomb efficiency was 89% through simulation.

[0064] Comparative Example 2

[0065] For a battery stack 20 with 10 parallel flow channels without the bypass current suppression device 10 installed, the number of battery cells in a single battery stack is 80 and the electrode area is 4000 cm 2 , output power 62kw. Based on Ohm's law and Kirchhoff's law, an equivalent circuit model was established, and the coulomb efficiency was 83% through simulation.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A bypass current suppression device, characterized in that: The invention comprises an infusion structure, an opening and closing member and a magnetic member, wherein the infusion structure is provided with an inlet and an outlet, wherein a first chamber connected to the inlet, a second chamber connected to the outlet, and a drainage hole connected to the first chamber and the second chamber are provided inside the infusion structure, wherein the opening and closing member is movably arranged in the second chamber, and the magnetic member is arranged on the infusion structure; the opening and closing member can close the drainage hole under the action of the magnetic force provided by the magnetic member, so that the first chamber and the second chamber are not connected; the opening and closing member can open the drainage hole under the action of the pressure of the electrolyte in the first chamber, so that the first chamber and the second chamber are connected; the magnetic member is an electromagnet, and the bypass current suppression device also comprises a current regulating device for regulating the current intensity passing through the electromagnet and a controller for controlling the current intensity of the current regulating device according to the electrolyte flow rate, and the current intensity I passing through the electromagnet satisfies the following formula: I=(kQδ / N)*(ρs’ / (μ0 S 3 )) 1 / 2 ; Where, I is the current intensity passing through the electromagnet, in A; N is the number of turns of the electromagnet coil; μ0 is the vacuum magnetic permeability, and its value is 4π*10 -7 kg·m / (s 2 A 2 );s' is the magnetic circuit cross-sectional area of ​​the electromagnet, unit is m 2 ; δ is the air gap length, in m; k is the magnetic enhancement coefficient, which is 1.5~10; Q is the average flow rate of electrolyte per unit time (tT, t) in the tube shell, in m 3 / s, where t is the current moment, T is the preset time period, and ρ is the electrolyte density in kg / m 3 ; S is the force area of ​​the opening and closing member facing the first cavity side squeezed by the electrolyte, the unit is m 2 .

2. The bypass current suppression device according to claim 1, characterized in that: The infusion structure includes a tube shell and an annular tube neck arranged inside the tube shell, the annular tube neck divides the inside of the tube shell into the first chamber and the second chamber, the annular hole of the annular tube neck constitutes the drainage hole, one end of the tube shell is provided with the liquid inlet, and the other end of the tube shell is provided with the liquid outlet.

3. The bypass current suppression device according to claim 2, characterized in that: The opening and closing member comprises a metal flap hinged on the annular tube neck.

4. The bypass current suppression device according to claim 1, characterized in that: An insulating layer is disposed on at least one side surface of the opening and closing member.

5. The bypass current suppression device according to claim 1, characterized in that: The bypass current suppression device further comprises a buffer component for limiting the flipping angle of the opening and closing member, and the buffer component comprises a base arranged in the second chamber and an elastic member arranged on the base.

6. The bypass current suppression device according to claim 2, characterized in that: A step structure is provided in the annular hole of the annular tube neck, the magnetic component is embedded in the annular hole of the annular tube neck, and the magnetic component is supported on the end surface of the step structure away from the opening and closing component.

7. The bypass current suppression device according to claim 6, characterized in that: An annular pad is provided on the end surface of the step structure facing the opening and closing member.

8. The bypass current suppression device according to any one of claims 1 to 7, characterized in that: The magnetic part is a first magnet, and the opening and closing part is provided with a second magnet.

9. A liquid flow battery, characterized in that: The bypass current suppression device comprises the bypass current suppression device according to any one of claims 1 to 8.

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