A bifunctional structured flow battery electrode mat
By combining carbon cloth and carbon felt in a carbon fiber structure to form a symmetrical structure and pre-assembling it with glue, the problems of strength and active area of carbon fiber felt in vanadium redox flow batteries are solved, improving energy conversion efficiency and reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HONGYAO GREEN ENERGY DEVELOPMENT (JIANGSU) CO LTD
- Filing Date
- 2025-07-31
- Publication Date
- 2026-07-14
Smart Images
Figure CN224501914U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of vanadium redox flow battery technology, and in particular to a dual-functional flow battery electrode felt. Background Technology
[0002] Vanadium redox flow batteries (VRFBs) are a type of high-capacity energy storage battery, mainly composed of a pump, a storage tank, and a stack. The stack is mainly assembled from current collectors, bipolar plates, electrodes, and a separator.
[0003] Carbon fiber felt electrodes are a key component of vanadium redox flow batteries, and their performance directly affects the energy efficiency of the flow battery.
[0004] In traditional technologies, the performance optimization of carbon fiber felt electrodes can be achieved in two ways: 1. To reduce contact resistance, a certain compression ratio of the electrode felt is required, which leads to a decrease in the porosity of the electrode felt, a larger internal mass transfer resistance, and a greater consumption of mass transfer resistance energy; 2. To meet the mass transfer requirements inside the fuel cell stack, additional pump consumption is required, which reduces the energy efficiency of the system.
[0005] To overcome these two problems, recent improvements to carbon felt or bipolar plates mainly involve creating flow channels on the surface of the bipolar plate or creating grooves or flow channels on the surface of the electrode felt to reduce the resistance inside the stack. However, adding flow channels to the surface of the bipolar plate reduces the strength of the bipolar plate, making it prone to short circuits in the battery. This necessitates increasing the thickness of the flow channel bipolar plate. The method to increase the thickness is usually to attach an additional flow channel plate to the surface of the bipolar plate, but this method carries the risk of flow channel collapse during long-term operation. For example, Chinese patent "A porous carbon felt structure" (patent number: CN119419301A) uses multiple channels on the carbon felt plate to reduce electrode felt resistance, but this reduces the strength and active area of the carbon felt. Chinese patent "Preparation method and system of carbon felt electrode with flow channel" (patent number: CN116072890A) uses a carving method to carve flow channels on the surface of porous carbon fiber felt. Although this method can improve the mass transfer of electrolyte inside the stack, it reduces the strength of the carbon felt, and the carving method is inefficient and costly. Chinese patent "A microchannel carbon felt design for improving the performance of flow batteries" (patent number: CN116053499A) uses microchannels set on one side of the carbon felt plane, which can reduce the pressure drop inside the stack, but cutting the carbon felt causes a significant reduction in the strength of the carbon felt.
[0006] Therefore, how to reduce contact resistance, ensure mass transfer efficiency, and also maintain the strength and active area of the electrode felt has become a problem that needs to be solved by those in the field. Summary of the Invention
[0007] In order to overcome the shortcomings of the prior art, the purpose of this utility model is to provide a dual-functional structure flow battery electrode felt that can reduce contact resistance, ensure mass transfer efficiency, and at the same time ensure the strength and active area of the electrode felt.
[0008] The objective of this utility model is achieved through the following technical solution:
[0009] According to an embodiment of this disclosure, a dual-function flow battery electrode felt is provided, including a proton exchange membrane, with carbon fiber structures disposed on opposite sides of the proton exchange membrane, and bipolar plates disposed on the side of each carbon fiber structure facing away from the proton exchange membrane; wherein, the carbon fiber structure includes carbon cloth and carbon felt.
[0010] As a preferred embodiment, the thickness of the carbon fiber structure falls within the range of 4.2~4.5μm or 2.0~2.5μm.
[0011] As a preferred embodiment, the compression ratio of the carbon fiber structure is 30%.
[0012] As a preferred option, the two carbon cloths located on both sides of the proton exchange membrane are arranged symmetrically with the proton exchange membrane as the center.
[0013] As a preferred option, the two carbon felts on both sides of the proton exchange membrane are arranged symmetrically with the proton exchange membrane as the center.
[0014] As a preferred embodiment, the pore size of the carbon cloth is larger than that of the carbon felt.
[0015] As a preferred embodiment, in the carbon fiber structure, the carbon cloth surface near the edge is bonded to carbon felt with adhesive.
[0016] As a preferred embodiment, the proton exchange membrane, carbon cloth, carbon felt, and bipolar plate are arranged in parallel to each other.
[0017] As a preferred embodiment, the specific surface area of the carbon felt is greater than that of the carbon cloth.
[0018] As a preferred embodiment, the thickness of the carbon felt is greater than the thickness of the carbon cloth.
[0019] In summary, compared with the prior art, this utility model has the following beneficial effects:
[0020] 1. This application combines carbon felt and carbon cloth to form a carbon fiber structure; carbon cloth has the characteristics of high mechanical strength and low fluid resistance, and is used to provide flow channel function; carbon felt has high electrochemical reactivity function; the combination of carbon cloth and carbon felt not only ensures the mechanical strength and reactivity of the flow battery electrode felt, but also reduces the internal resistance of the stack and improves the energy conversion efficiency.
[0021] 2. In this application, both carbon cloths and two carbon felts are symmetrical structures centered on the proton exchange membrane, which can balance the internal resistance of the positive and negative electrodes on both sides of the proton exchange membrane.
[0022] 3. In this application, the carbon cloth has large pores and a small compressibility, which is conducive to the transfer of electrode liquid inside the pores, thereby reducing mass transfer resistance; in addition, the carbon cloth has excellent mechanical strength and strong durability, which meets the requirements for long-term operation of flow batteries.
[0023] 4. In this application, carbon cloth and carbon felt are pre-assembled using glue, which reduces the complexity of assembly. Attached Figure Description
[0024] Figure 1 This is an explosion diagram of the electrode felt in Embodiment 1 of this utility model;
[0025] Figure 2 This is an explosion diagram of the electrode felt in Embodiment 2 of this utility model;
[0026] The numbers and letters in the diagram represent the names of the corresponding components:
[0027] 1. Bipolar plate; 2. Carbon cloth; 3. Carbon felt; 4. Proton exchange membrane. Detailed Implementation
[0028] This invention provides a dual-function flow battery electrode felt, including a proton exchange membrane, with carbon fiber structures disposed on opposite sides of the proton exchange membrane, and bipolar plates disposed on the side of each carbon fiber structure facing away from the proton exchange membrane; wherein, the carbon fiber structure includes carbon cloth and carbon felt.
[0029] In this way, the combined electrode of carbon felt and carbon cloth eliminates the need to attach or carve flow channels on the bipolar plate, or to cut the required flow channels or holes on the surface of the carbon felt, thereby reducing production costs and improving mass transfer without altering the structure of the bipolar plate and carbon felt. This application utilizes the high mechanical strength and low fluid resistance of carbon cloth to provide flow channels; it also utilizes the high electrochemical reactivity of carbon felt; combining carbon cloth and carbon felt ensures the mechanical strength and reactivity of the flow battery electrode felt while reducing the internal resistance of the stack and improving energy conversion efficiency.
[0030] Specifically, the thickness range of the carbon fiber structure is 4.2~4.5μm or 2.0~2.5μm.
[0031] Specifically, the compression ratio of the carbon fiber structure is 30%.
[0032] Thus, when the compression ratio is around 30%, both carbon felt and carbon cloth have high electrochemical performance in vanadium electrolyte conversion.
[0033] Specifically, the two carbon cloth sheets located on both sides of the proton membrane are arranged symmetrically with the proton membrane as the center.
[0034] Specifically, the two carbon felts on both sides of the proton membrane are arranged symmetrically with the proton membrane as the center.
[0035] In this way, both carbon cloths and two carbon felts are symmetrical structures centered on the proton exchange membrane, which can balance the internal resistance of the positive and negative electrodes on both sides of the proton exchange membrane.
[0036] Specifically, the pore size of the carbon cloth is larger than that of the carbon felt.
[0037] In this way, the carbon cloth has large pores and a small compressibility, which is conducive to the transfer of electrode liquid inside the pores, thereby reducing mass transfer resistance; in addition, the carbon cloth has excellent mechanical strength and strong durability, which meets the requirements for long-term operation of flow batteries.
[0038] Specifically, in the carbon fiber structure, the carbon cloth surface near the edge is bonded to carbon felt with adhesive.
[0039] In this way, the use of glue for pre-assembly reduces the complexity of assembly; at the same time, the edges of the carbon cloth are glued to the carbon felt to form a two-in-one component, reducing misalignment deviations when assembling the carbon felt and carbon cloth.
[0040] Specifically, the proton exchange membrane, carbon cloth, carbon felt, and bipolar plate are arranged in parallel to each other.
[0041] Specifically, the specific surface area of the carbon felt is greater than that of the carbon cloth.
[0042] In this way, the carbon felt has a large specific surface area and higher activity.
[0043] Specifically, the thickness of the carbon felt is greater than the thickness of the carbon cloth.
[0044] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0045] Example 1
[0046] like Figure 1 As shown, a dual-function flow battery electrode felt has a core battery unit comprising a bipolar plate 1, a carbon cloth 2, a carbon felt 3, a proton exchange membrane 4, a carbon felt 3, a carbon cloth 2, and a bipolar plate 1 arranged in parallel in sequence.
[0047] In this way, the flow channel and the electrode can achieve dual functions.
[0048] During implementation, carbon cloth and carbon felt can be pre-assembled using adhesives such as hot melt adhesive and double-sided tape.
[0049] In this embodiment, the carbon cloth is placed close to the bipolar plate to achieve the function of opening the flow channel of the bipolar plate.
[0050] Example 2
[0051] like Figure 2 As shown, a dual-function flow battery electrode felt has a core battery unit comprising a bipolar plate 1, a carbon felt 3, a carbon cloth 2, a proton exchange membrane 4, a carbon cloth 2, a carbon felt 3, and the bipolar plate 1 arranged in parallel in sequence.
[0052] In this way, the flow channel and the electrode can achieve dual functions.
[0053] During implementation, carbon cloth and carbon felt can be pre-assembled using adhesives such as hot melt adhesive and double-sided tape.
[0054] In this embodiment, the carbon cloth is placed close to the proton exchange membrane to achieve the function of opening flow channels or dividing holes on the surface of the carbon felt.
[0055] Example 3
[0056] A vanadium redox flow battery system includes a power unit for electrolyte conversion, a capacity unit for storing electrolyte, a pump control unit for delivering electrolyte, a heat exchange unit for thermal efficiency management, and a system control unit.
[0057] Specifically, the capacity unit for storing electrolyte is based on an electric stack to realize the conversion of electrical energy and chemical energy.
[0058] Specifically, the method of constructing a fuel cell stack includes the following steps:
[0059] A. Obtain the core battery pack unit of Example 1 or Example 2;
[0060] B. Connect the core battery pack units from step A in series, and connect the current collector and end plate at the outermost end to form a complete battery stack.
[0061] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this utility model. These are all equivalent modifications and improvements made to the above embodiments based on the essential technology of this utility model, and all of these fall within the protection scope of this utility model.
Claims
1. A dual-functional flow battery electrode felt, characterized in that, It includes a proton exchange membrane, with carbon fiber structures disposed on opposite sides of the proton exchange membrane, and bipolar plates disposed on the side of each carbon fiber structure facing away from the proton exchange membrane; wherein, the carbon fiber structure includes carbon cloth and carbon felt.
2. The dual-functional flow battery electrode felt according to claim 1, characterized in that, The thickness of the carbon fiber structure falls within the range of 4.2~4.5μm or 2.0~2.5μm.
3. The dual-functional flow battery electrode felt according to claim 1, characterized in that, The compression ratio of the carbon fiber structure is 30%.
4. The dual-functional flow battery electrode felt according to claim 1, characterized in that, The two carbon cloth sheets located on both sides of the proton membrane are arranged symmetrically with the proton membrane as the center.
5. The dual-functional flow battery electrode felt according to claim 1, characterized in that, The two carbon felts on both sides of the proton membrane are arranged symmetrically with the proton membrane as the center.
6. The dual-functional flow battery electrode felt according to claim 1, characterized in that, The pores of the carbon cloth are larger than those of the carbon felt.
7. The dual-functional flow battery electrode felt according to claim 1, characterized in that, In the carbon fiber structure, the carbon cloth surface near the edge is bonded to carbon felt with adhesive.
8. The dual-functional flow battery electrode felt according to claim 1, characterized in that, The proton exchange membrane, carbon cloth, carbon felt, and bipolar plate are arranged in parallel to each other.
9. The dual-functional flow battery electrode felt according to claim 1, characterized in that, The specific surface area of the carbon felt is greater than that of the carbon cloth.
10. The dual-functional flow battery electrode felt according to claim 1, characterized in that, The thickness of the carbon felt is greater than the thickness of the carbon cloth.