A novel electrode structure design and application

Abstract

The application discloses a novel electrode structure design and application and belongs to the technical field of flow battery. In view of the problem that in the existing flow battery, the flow resistance of electrolyte in the electrode material is large, the pump consumption is increased, and thus the integrated system efficiency is reduced, the application provides a novel electrode structure design: the battery electrode is spliced by multiple carbon materials with different thicknesses, and the electrodes with different thicknesses are compressed to the same thickness by using a flow frame, a gasket and a bipolar plate. The method reduces the porosity loss of the carbon material electrode in the compression process, reduces the flow resistance of the electrolyte, improves the pump consumption and does not affect the electrolyte ion conduction resistance in the electrode, so that the system integrated efficiency is improved. The method is simple in operation, easy to realize and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of flow battery technology, and in particular relates to a novel electrode structure design and application. Background Technology

[0002] With the gradual depletion of traditional energy sources and the corresponding environmental problems, the utilization of renewable energy sources such as wind and solar power has attracted widespread attention and developed rapidly. However, the continuous power supply of these two energy sources has become the biggest technical challenge, and energy storage technology is the best solution to this challenge.

[0003] Among existing energy storage technologies, flow batteries are considered an ideal route for large-scale energy storage due to their advantages such as fast response, safe operation, relatively inexpensive materials, long lifespan, and independence of output power and energy storage capacity. Besides electrochemical performance, the most significant factor affecting the efficiency of flow battery systems is the pump consumption of the electrolyte circulation pump. This pump consumption primarily stems from the design of the flow channel piping in the flow battery and the flow resistance of the electrolyte through the graphite felt. The flow resistance of the electrolyte through the graphite felt accounts for over 70% of the total pump consumption, and current patents do not offer solutions to reduce this flow resistance.

[0004] In view of this, this patent proposes a novel electrode structure design and application to reduce the flow resistance of the electrolyte in the graphite felt, reduce pump consumption, and improve system efficiency. Summary of the Invention

[0005] The purpose of this invention is to propose a novel electrode structure design and application, which reduces the compression area of ​​the graphite felt electrode, decreases the porosity loss of the graphite felt, reduces the flow resistance of the electrolyte in the graphite felt, thereby reducing pump consumption and improving the efficiency of the flow battery energy storage system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A novel electrode structure design and application is characterized by being composed of three carbon materials of different thicknesses spliced ​​together, wherein the carbon materials on the left and right sides are thinner than the carbon material on the middle side, and the three electrodes of different thicknesses are compressed to the same thickness by using a flow frame, a sealing gasket, a bipolar plate, and a diaphragm.

[0008] Furthermore, the carbon material is one or more of graphite felt, carbon felt, or carbon cloth;

[0009] Furthermore, the thickness of the left-side carbon material and the right-side carbon material is 1~8mm;

[0010] Furthermore, the thickness of the intermediate carbon material is 2~10mm;

[0011] Furthermore, the fluid flow frame is made of one or more of PP, PE, and PVC, and has a thickness of 1~5mm;

[0012] Furthermore, the sealing gasket is made of one or more of EPDM rubber, silicone, and fluororubber, with a thickness of 1~5mm;

[0013] Furthermore, the bipolar plate is made of one or more of PP, PE, PVDF, and mixed with one or more of vermicular graphite, phosphorescent graphite, and flake graphite;

[0014] Furthermore, the membrane is either an ion exchange membrane or a porous membrane;

[0015] Furthermore, the various thicknesses of the graphite felt are 2 to 8 types;

[0016] The beneficial effects of this invention are:

[0017] 1. The thickness of the graphite felt can be precisely controlled by adjusting the thickness of the fluid flow frame and the gasket, thereby controlling the graphite felt compression rate and thus the felt porosity.

[0018] 2. While ensuring the compression ratio of graphite felt, the loss of graphite felt porosity is reduced by decreasing the compression area of ​​graphite felt electrodes, thereby reducing the flow resistance of electrolyte in graphite felt, thus reducing pump consumption and improving the efficiency of flow battery energy storage system.

[0019] 3. In this invention, only the thickest part of the graphite felt requires a large amount of compression, avoiding the need for a large amount of compression for the entire felt, thus reducing the cost of graphite felt. Moreover, this method is simple to operate and has strong practicality.

[0020] 4. This paper proposes an optimized solution for graphite felt, providing a new approach to reducing system pump consumption; Attached Figure Description

[0021] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below.

[0022] Figure 1 This is a schematic diagram of the graphite felt before compression in the embodiment;

[0023] Figure 2 This is a schematic diagram of the graphite felt after it has been compressed in the embodiment; Detailed Implementation

[0024] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention.

[0025] Example 1

[0026] like Figure 1 As shown, the electrode material is graphite felt with a porosity of 92%. The thickness of the graphite felt on the left side is 3 mm, the thickness of the graphite felt on the middle side is 6 mm, the thickness of the graphite felt on the right side is 3 mm, the thickness of the fluid flow frame is 2 mm, the thickness of the gasket is 1 mm, the thickness of the bipolar plate is 1 mm, the thickness of the diaphragm is 55 μm, and the compression ratio of the graphite felt on the middle side is 50%. Figure 1 It is assembled in a certain way. Figure 1 The structure will be compressed into a mirror image, and the compressed shape will be like... Figure 2 As shown, the thickness of the three types of graphite felt after compression is 3mm.

[0027] Permeability is calculated using the following Kozeny-Carmen formula.

[0028]

[0029] Where d is the average diameter of the carbon fibers in the porous electrode. Electrode porosity, For the undetermined coefficients in the relation, their values ​​are expressed as follows: =5.55 or =4.28 is the most common value. In this example, carbon fiber dendrites with a porosity of 10 μm and a porosity of 92% are used. With a value of 5.55, after determining the above parameters, the Comsol Multiphysics software was used for simulation to construct a two-dimensional model. In the material options, porous materials were constructed for graphite felt domains with different post-compression heights. Electrolyte was selected as the fluid. The porosity and permeability of graphite felt at different post-compression heights were calculated and assigned values. The physics field was selected as fluid flow - single-phase flow - laminar flow, and the porous medium domain was enabled. The inlet boundary was selected as fully developed flow-rate condition, and the corresponding flow rate and post-compression inlet height were set. The inlet and outlet pressure values ​​were calculated, and the pressure loss value was obtained by subtracting them, which was 10.51 kPa.

[0030] Example 2

[0031] like Figure 1 As shown, the electrode material is graphite felt with a porosity of 92%. The thickness of the graphite felt on the left side is 4 mm, the thickness of the graphite felt on the middle side is 6 mm, the thickness of the graphite felt on the right side is 5 mm, the thickness of the fluid flow frame is 2 mm, the thickness of the gasket is 1 mm, the thickness of the bipolar plate is 1 mm, the thickness of the diaphragm is 55 μm, the compression rate of the graphite felt on the left side is 25%, the compression rate of the graphite felt on the middle side is 50%, and the compression rate of the graphite felt on the right side is 40%. According to... Figure 1 It is assembled in a certain way. Figure 1 The structure will be compressed into a mirror image, and the compressed shape will be like... Figure 2As shown, the thickness of the three graphite felts after compression is 3mm, and the pressure loss after simulation using COMSOL software is 15.12kPa.

[0032] Comparative Example 1

[0033] The structure is the same as in Example 1, except that the electrode material is graphite felt with a porosity of 92% and an overall thickness of 6mm. The thicknesses of the gasket, bipolar plate, and diaphragm are also the same as in Example 1. The morphology after compression is the same. Figure 2 Similarly, the thickness of the compressed graphite felt is 3 mm, and the compression rate is 50%. Using the same calculation method, the pressure loss value is 19.99 kPa. Compared to Example 1, the pressure loss increases by 90.2%, and compared to Example 2, the pressure loss increases by 32.2%.

[0034] Example 3

[0035] like Figure 1 As shown, the electrode material is graphite felt with a porosity of 94%. The thickness of the graphite felt on the left side is 3 mm, the thickness of the graphite felt on the middle side is 4 mm, the thickness of the graphite felt on the right side is 3 mm, the thickness of the fluid flow frame is 2 mm, the thickness of the gasket is 1 mm, the thickness of the bipolar plate is 1 mm, the thickness of the diaphragm is 55 μm, and the compression ratio of the middle graphite felt is 25%. Figure 1 It is assembled in a certain way. Figure 1 The structure will be compressed into a mirror image, and the compressed shape will be like... Figure 2 As shown, the thickness of the three types of graphite felt after compression is 3 mm. Simulation using COMSOL software yielded a pressure loss of 6.68 kPa.

[0036] Comparative Example 2

[0037] like Figure 1 As shown, the electrode material is graphite felt with a porosity of 94%, and the overall thickness of the electrode material is graphite felt of 4 mm. The thickness of the gasket, bipolar plate, and diaphragm are the same as in Example 2, and the morphology after compression is the same. Figure 2 Similarly, the thickness of the compressed graphite felt is 3 mm, and the compression rate is 25%. Using the same calculation method, the pressure loss value is 8.35 kPa. Compared to Example 3, the pressure loss increased by 25%.

[0038] Example 4

[0039] like Figure 1 As shown, the electrode material is graphite felt with a porosity of 90%. The thickness of the graphite felt on the left side is 5 mm, the thickness of the graphite felt on the middle side is 8 mm, the thickness of the graphite felt on the right side is 6 mm, the thickness of the fluid flow frame is 3 mm, the thickness of the gasket is 2 mm, the thickness of the bipolar plate is 1 mm, and the thickness of the diaphragm is 55 μm. The compression rate of the graphite felt on the left side is 0%, the compression rate of the graphite felt on the middle side is 37.5%, and the compression rate of the graphite felt on the right side is 25%. According to... Figure 1 It is assembled in a certain way. Figure 1 The structure will be compressed into a mirror image, and the compressed shape will be like... Figure 2 As shown, the thickness of the three graphite felts after compression is 5 mm, and the pressure loss after simulation using COMSOL software is 8.03 kPa.

[0040] Comparative Example 3

[0041] like Figure 1 As shown, the electrode material is a graphite felt with a porosity of 90%, the same as in Example 4. The overall thickness of the electrode material is 8 mm. The thickness of the gasket, bipolar plate, and diaphragm are the same as in Example 2. The morphology after compression is the same as in Example 2. Figure 2 Similarly, the thickness of the compressed graphite felt is 5 mm, the compression rate is 37.5%, and the pressure loss value is 11.59 kPa calculated using the same method. Compared with Example 4, the pressure loss increased by 44.3%.

Claims

1. A novel electrode structure design and application, characterized in that, It is made of various carbon materials of different thicknesses, and multiple electrodes of different thicknesses are compressed to the same thickness by using a flow frame, sealing gasket, bipolar plate and diaphragm.

2. A novel electrode structure design and application according to claim 1, characterized in that: The carbon material is one or more of graphite felt, carbon felt, or carbon cloth.

3. A novel electrode structure design and application according to claim 1, characterized in that: The thickness of the carbon material on the left and right sides is 1~8mm.

4. A novel electrode structure design and application according to claim 1, characterized in that: The thickness of the intermediate carbon material is 2~10mm.

5. A novel electrode structure design and application according to claim 1, characterized in that: The fluid flow frame is made of one or more of PP, PE, and PVC, with a thickness of 1~5mm.

6. A novel electrode structure design and application according to claim 1, characterized in that: The sealing gasket is made of one or more of EPDM rubber, silicone, and fluororubber, with a thickness of 1~5mm.

7. A novel electrode structure design and application according to claim 1, characterized in that: The bipolar plate is made of one or more of PP, PE, PVDF, and mixed with one or more of vermicular graphite, phosphorescent graphite, and flake graphite.

8. A novel electrode structure design and application according to claim 1, characterized in that: The membrane is an ion exchange membrane or a porous membrane.

9. A novel electrode structure design and application according to claim 1, characterized in that: The various thicknesses of graphite felt mentioned are 2 to 8 types.

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