Device and method for suppressing leakage current of public pipeline of flow battery

Abstract

The invention discloses a leakage current suppression device for a common pipeline of a flow battery, which is applied to a common electrolyte manifold of a flow battery stack, and the manifold is used for connecting a plurality of battery units in the stack with an external electrolyte storage tank; the leakage current suppression device for the common pipeline of the flow battery comprises a plurality of floating electrodes and a potential dissipation region, due to the conductivity and contact with electrolyte, when leakage current tries to pass through, the floating electrodes are like the same passive and passively responsive electrode. And according to the potential of the local electrolyte, charges can be adsorbed or released, so that an induced potential is formed on the surface of the electrolyte. Due to the existence of the induced potential, the potential distribution of the electrolyte in the area near the floating electrode can be locally changed, so that the electrolyte tends to be flat. Visually speaking, the floating electrode'breaks' the long-distance continuous potential gradient in the manifold into a plurality of small sections, and the potential gradient of each small section is remarkably reduced, so that the total leakage current is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of current suppression devices, and in particular to a device and method for suppressing leakage current in the common pipe of a flow battery. Background Technology

[0002] Flow batteries are a promising large-scale energy storage technology. Their core component is the battery stack, which is charged and discharged by pumping externally stored liquid electrolyte. In the design of flow battery stacks, common inlet and outlet manifolds (i.e., current collectors or manifolds) are typically used to distribute the electrolyte to each cell. However, because the electrolyte in these common manifolds is conductive, and there are potential differences between the cells within the stack, this leads to the formation of a bypass current, or "leakage current," within the common manifold.

[0003] Leakage current can have a series of negative effects, including: leakage current is a non-dissipative energy source, which directly leads to a decrease in battery charging and discharging efficiency; unwanted electrochemical reactions of the electrolyte occur in the manifold, accelerating battery self-discharge; long-term leakage may lead to an imbalance of components between different electrolyte storage tanks; leakage current may cause corrosion of manifold materials or decomposition side reactions of the electrolyte, affecting battery life and safety.

[0004] Existing methods for suppressing leakage current mainly include: extending the manifold length, reducing the manifold cross-sectional area to increase resistance; using non-conductive diaphragms or segmented flow path designs; or using complex control systems. However, these methods often have limitations, such as increased voltage drop, complex fluid management, high manufacturing costs, or the need for additional energy input. Therefore, the industry still needs a simple, efficient, and easy-to-implement leakage current suppression solution that requires no external energy support. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is that leakage current suppression methods have problems such as large voltage drop and complex fluid management.

[0006] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes a leakage current suppression device for a common pipeline of a flow battery, which is applied to the common electrolyte manifold of a flow battery stack. The manifold is used to connect multiple battery cells in the stack to an external electrolyte storage tank. The leakage current suppression device for the common pipeline of the flow battery includes multiple floating electrodes and a potential dissipation region. The floating electrodes and potential dissipation regions are spaced apart along the length of the common electrolyte manifold inside the manifold, directly contacting the electrolyte flowing through the manifold, while not being electrically connected to external circuits or any battery cells of the stack, and are in an electrically floating state.

[0007] In a preferred embodiment of the leakage current suppression device for the common pipeline of the flow battery described in this invention: the floating electrode and the potential dissipation region are made of a conductive material that is resistant to electrolyte corrosion, and the material is selected from at least one of graphite, carbon felt, porous carbon material, platinum, gold, platinum alloy, and gold alloy.

[0008] In a preferred embodiment of the leakage current suppression device for the common pipeline of the flow battery described in this invention: the shape of the floating electrode and the potential dissipation zone is selected from one of the following: plate-shaped, mesh-shaped, porous block-shaped, fiber bundle-shaped, and filled granular.

[0009] In a preferred embodiment of the leakage current suppression device for the common pipeline of the flow battery described in this invention: the floating electrode and the potential dissipation region are uniformly or non-uniformly distributed along the length of the manifold, and their spacing and quantity are optimized according to the voltage of the battery stack, the conductivity of the electrolyte, and the geometric dimensions of the manifold.

[0010] In a preferred embodiment of the leakage current suppression device for the common pipeline of the flow battery described in this invention: the floating electrode and the potential dissipation region are fixed inside the manifold by a bracket and an embedded structure; The floating electrode and potential dissipation region are integrated with the manifold body using 3D printing technology. The manifold body is made of conductive polymer material, with non-conductive insulators embedded in specific areas to achieve electrical floating.

[0011] In a preferred embodiment of the common pipeline leakage current suppression device for flow batteries according to the present invention: the common pipeline leakage current suppression device for flow batteries is applicable to the common electrolyte manifold of the stack of vanadium redox flow batteries, zinc-bromine flow batteries or iron-chromium flow batteries; In a strongly acidic oxidizing electrolyte, the floating electrode and potential dissipation region are made of a titanium substrate coated with platinum.

[0012] This invention also proposes a method for suppressing leakage current in the common conduit of a flow battery, comprising the following steps: Inside the common electrolyte manifold of the flow battery stack, multiple electrically floating conductive elements are arranged at intervals along the length of the manifold. The conductive elements are the floating electrodes and potential dissipation regions in the above-mentioned common pipeline leakage current suppression device of the flow battery. The electrolyte flows through the manifold and comes into contact with the electrically floating conductive element; When leakage current flows through the manifold, the electrically floating conductive element induces a potential due to contact with the electrolyte. This induced potential partially cancels the potential gradient of the electrolyte in the manifold, interrupting or weakening the continuous leakage path. The locally high surface area provided by the electrically floating conductive element promotes minute and harmless electrochemical side reactions, dissipates some leakage energy, and does not affect the normal operation of the main battery.

[0013] In a preferred embodiment of the method for suppressing leakage current in the common pipeline of a flow battery according to the present invention, the method further includes a step of determining the optimal spacing and number of floating electrodes through finite element analysis numerical simulation or experimental testing, so as to achieve a balance between leakage current suppression effect and voltage drop. The more floating electrodes there are, the better the leakage current suppression effect and the greater the corresponding voltage drop.

[0014] In a preferred embodiment of the method for suppressing leakage current in the common pipeline of a flow battery according to the present invention, the method further includes a step of etching the surface of the floating electrode, coating it with a non-main reaction catalyst, or preparing a micro / nano structure to optimize the induced potential or local dissipation capability of the floating electrode.

[0015] In a preferred embodiment of the method for suppressing leakage current in the common pipeline of a flow battery according to the present invention: when the floating electrode and the potential dissipation area are plate-shaped, their thickness is 1-3 mm and their size is smaller than the inner diameter of the manifold, and the electrolyte flows from the periphery or surface of the plate-shaped floating electrode and the potential dissipation area; when it is a porous carbon block, it is made of carbon felt or carbon foam and is fixed in the manifold by compression or non-conductive adhesive.

[0016] The beneficial effects of this invention are as follows: By setting floating electrodes and potential dissipation regions, due to their conductivity and contact with the electrolyte, these floating electrodes act as passive, reactive electrodes when leakage current attempts to pass through. Depending on the local electrolyte potential, they adsorb or release charges, thereby forming an induced potential on their surface. The presence of this induced potential locally alters the potential distribution of the electrolyte in the vicinity of the floating electrodes, making it more even. Figuratively speaking, the floating electrodes "break" the long-distance continuous potential gradient within the manifold into several smaller segments, each with a significantly reduced potential gradient, thereby greatly reducing the total leakage current. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein: Figure 1 The overall structural diagram of the leakage current suppression device for the common pipeline of the flow battery is shown. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0020] Reference Figure 1 This embodiment provides a leakage current suppression device for a common pipeline of a flow battery, applied to the common electrolyte manifold 100 of a flow battery stack. The manifold 100 is used to connect multiple battery cells 400 within the stack to an external electrolyte storage tank 500. The device is characterized by including multiple floating electrodes 200 and potential dissipation regions. The floating electrodes 200 and potential dissipation regions are spaced apart inside the common electrolyte manifold 100 along its length and are in direct contact with the electrolyte flowing through the manifold 100. At the same time, they are not electrically connected to any external circuit or any battery cell 400 in the stack and are in an electrically floating state.

[0021] Function: By setting up an electrically floating electrode structure, the potential gradient in the electrolyte can be offset by the induced potential without interfering with the main circuit of the battery, thus blocking the continuous conduction path of leakage current from the source.

[0022] As an optional embodiment, the floating electrode 200 and the potential dissipation region are made of a conductive material that is resistant to electrolyte corrosion. The material is selected from at least one of graphite, carbon felt, porous carbon material, platinum, gold, platinum alloy, gold alloy or conductive polymer material. This ensures that the electrode maintains stable conductivity in a highly corrosive electrolyte environment, avoids device failure due to material corrosion, and ensures the electrode's sensitive response to potential changes in the electrolyte.

[0023] As an optional embodiment, the shape of the floating electrode 200 and the potential dissipation region is selected from one of the following: plate-shaped, mesh-shaped, porous block-shaped, fiber bundle-shaped, or filled granular.

[0024] Optimizing the electrode shape increases the contact area with the electrolyte, thereby improving the potential sensing efficiency; at the same time, it can reduce the resistance to electrolyte flow and avoid excessive system voltage drop caused by device design.

[0025] As an optional embodiment, the floating electrode 200 and the potential dissipation region are uniformly or non-uniformly distributed along the length of the manifold 100. Their spacing and number are optimized according to the voltage of the stack, the conductivity of the electrolyte, and the geometric dimensions of the manifold 100. By designing the electrode distribution parameters in a targeted manner, the best leakage current suppression effect can be achieved in flow battery systems of different specifications, taking into account both suppression efficiency and system compatibility.

[0026] As an optional embodiment, the floating electrode 200 and the potential dissipation region are fixed inside the manifold 100 by a bracket and an embedded structure to ensure stability during electrolyte flow. The floating electrode 200 and the potential dissipation region are integrated with the manifold 100 body using 3D printing technology. The manifold 100 body is made of conductive polymer material, and non-conductive insulators are embedded in specific areas to achieve electrical floating, ensuring the structural stability of the electrode in high-flow-rate electrolyte. At the same time, the integrated manufacturing process improves the sealing of the device and avoids electrolyte leakage. The setting of non-conductive insulators can precisely achieve electrical isolation of the electrodes.

[0027] As an optional embodiment, the device is applicable to the common electrolyte manifold 100 of the stack of vanadium redox flow batteries, zinc-bromine flow batteries, or iron-chromium flow batteries; in strongly acidic oxidizing electrolytes, the floating electrode 200 and the potential dissipation region are made of titanium-based material coated with platinum, so as to realize the adaptability of the device to different types of flow battery systems. By selecting special materials for specific corrosive environments, the service life of the device can be significantly extended.

[0028] A method for suppressing leakage current in the common conduit of a flow battery includes the following steps: Inside the common electrolyte manifold 100 of the flow battery stack, a plurality of electrically floating conductive elements are arranged at intervals along the length of the manifold 100. The conductive elements are the floating electrode 200 and the potential dissipation region in the above-mentioned common pipeline leakage current suppression device of the flow battery. The electrolyte flows through the manifold 100 and comes into contact with the electrically floating conductive element. When leakage current flows through manifold 100, the electrically floating conductive element induces a potential due to contact with the electrolyte. This induced potential partially cancels the potential gradient of the electrolyte in manifold 100, interrupting or weakening the continuous leakage path. By utilizing the locally high surface area provided by electrically floating conductive elements, trace and harmless electrochemical side reactions are promoted, dissipating some leakage energy without affecting the normal operation of the main battery.

[0029] The leakage current is suppressed through a dual mechanism of potential cancellation and energy dissipation, which can both block the leakage path and safely consume the leakage energy without interfering with the main reaction of the battery.

[0030] As an optional embodiment, it also includes the step of determining the optimal spacing and number of floating electrodes 200 through finite element analysis numerical simulation or experimental testing, so as to achieve a balance between leakage current suppression effect and voltage drop. The more floating electrodes 200 there are, the better the leakage current suppression effect and the greater the corresponding voltage drop. This provides a scientific parameter optimization method, which can find the optimal balance between suppression effect and fluid resistance according to actual system requirements, thereby improving the practicality of the method.

[0031] As an optional embodiment, the method also includes etching the surface of the floating electrode 200, coating it with a non-main reaction catalyst, or preparing a micro / nano structure to optimize the induced potential or local dissipation capability of the floating electrode 200; by modifying the surface to enhance the potential sensing sensitivity and energy dissipation efficiency of the electrode, the leakage current suppression effect is further improved, while avoiding interference with the main reaction of the battery.

[0032] As an optional embodiment, when the floating electrode 200 and the potential dissipation area are plate-shaped, their thickness is 1-3 mm and their size is smaller than the inner diameter of the manifold 100. The electrolyte flows around or over the surface of the plate-shaped floating electrode 200 and the potential dissipation area. When it is a porous carbon block, it is made of carbon felt or carbon foam and is fixed in the manifold 100 by compression or non-conductive adhesive. Specific parameter standards are formulated for electrodes of different shapes to ensure that while achieving efficient leakage current suppression, the impact on electrolyte flow is controlled within a reasonable range to ensure normal system operation.

[0033] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A leakage current suppression device for a common pipeline of a flow battery, characterized in that: A common electrolyte manifold (100) is used in a flow battery stack to connect multiple battery cells (400) in the stack to an external electrolyte storage tank (500). The leakage current suppression device for the common pipeline of the flow battery includes multiple floating electrodes (200) and a potential dissipation region; The floating electrode (200) and the potential dissipation region are spaced apart inside the manifold (100) along the length of the common electrolyte manifold (100), and are in direct contact with the electrolyte flowing through the manifold (100). At the same time, they are not electrically connected to the external circuit and any battery cell (400) of the stack, and are in an electrically floating state.

2. The leakage current suppression device for the common pipeline of a flow battery according to claim 1, characterized in that: The floating electrode (200) and the potential dissipation region are made of a conductive material that is resistant to electrolyte corrosion, the material being selected from at least one of graphite, carbon felt, porous carbon material, platinum, gold, platinum alloy, and gold alloy.

3. The leakage current suppression device for the common pipeline of a flow battery according to claim 1, characterized in that: The shape of the floating electrode (200) and the potential dissipation region is selected from one of the following: plate-shaped, mesh-shaped, porous block-shaped, fiber bundle-shaped, and filled granular.

4. The leakage current suppression device for the common pipeline of a flow battery according to claim 1, characterized in that: The floating electrode (200) and the potential dissipation region are uniformly distributed along the length of the manifold (100), and their spacing and number are optimized according to the voltage of the fuel cell stack, the conductivity of the electrolyte, and the geometric dimensions of the manifold (100).

5. The leakage current suppression device for the common pipeline of a flow battery according to claim 1, characterized in that: The floating electrode (200) and potential dissipation region are fixed inside the manifold (100) by a bracket and an embedded structure; The floating electrode (200) and potential dissipation region are integrated with the manifold (100) body through 3D printing technology. The manifold (100) body is made of conductive polymer material and embedded with non-conductive insulator to achieve electrical floating.

6. The leakage current suppression device for the common pipeline of a flow battery according to claim 1, characterized in that: The leakage current suppression device for the common pipeline of the flow battery is applicable to the common electrolyte manifold (100) of the stack of vanadium redox flow batteries, zinc-bromine flow batteries and iron-chromium flow batteries. In a strongly acidic oxidizing electrolyte, the floating electrode (200) and the potential dissipation region are made of a titanium substrate coated with platinum.

7. A method for suppressing leakage current in the common conduit of a flow battery, characterized in that, Includes the following steps: Inside the common electrolyte manifold (100) of the flow battery stack, a plurality of electrically floating conductive elements are arranged at intervals along the length of the manifold (100). The conductive elements are the floating electrode (200) and potential dissipation region in the common pipeline leakage current suppression device of the flow battery as described in any one of claims 1-6. The electrolyte flows through the manifold (100) and comes into contact with the electrically floating conductive element; When leakage current flows through the manifold (100), the electrically floating conductive element induces a potential due to contact with the electrolyte. This induced potential partially cancels the potential gradient of the electrolyte in the manifold (100), interrupting or weakening the continuous leakage path. The locally high surface area provided by the electrically floating conductive element promotes minute and harmless electrochemical side reactions, dissipates some leakage energy, and does not affect the normal operation of the main battery.

8. The method for suppressing leakage current in the common pipeline of a flow battery according to claim 7, characterized in that: It also includes the step of determining the optimal spacing and number of floating electrodes (200) through numerical simulation of finite element analysis or experimental testing, so as to achieve a balance between leakage current suppression effect and voltage drop. The more floating electrodes (200) there are, the better the leakage current suppression effect and the greater the corresponding voltage drop.

9. The method for suppressing leakage current in the common pipeline of a flow battery according to claim 7, characterized in that: It also includes processing steps such as etching the surface of the floating electrode (200), coating it with a non-main reaction catalyst, or preparing micro / nano structures to optimize the induced potential or local dissipation capability of the floating electrode (200).

10. The method for suppressing leakage current in the common pipeline of a flow battery according to claim 7, characterized in that: When the floating electrode (200) and the potential dissipation region are plate-shaped, their thickness is 1-3 mm and their size is smaller than the inner diameter of the manifold (100). The electrolyte flows from the periphery or surface of the plate-shaped floating electrode (200) and the potential dissipation region. When it is a porous carbon block, it is made of carbon felt or carbon foam and fixed in the manifold (100) by compression or non-conductive adhesive.

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