Visual transparent flow battery stack without charging and discharging
By designing a visual transparent liquid flow battery stack without charging and discharging, and using high-transparent materials and aqueous gelatin solution, the problem of difficulty in accurately simulating the flow of electrolyte in the prior art is solved, and intuitive optimization of the stack structure is achieved, improving the stack performance and saving costs.
Patent Information
- Application Number
- CN202510085563.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-20
- Publication Date
- 2025-05-13
AI Technical Summary
It is difficult for existing flow battery stacks to accurately simulate the electrolyte flow during design and assembly, resulting in a large difference between design and actual testing. The traditional optimization methods are relatively traditional and lack intuitive visualization tools.
Design a visual transparent liquid flow battery stack without charging and discharging. It uses high transparent acrylic or PC board material to make transparent end plates, transparent electrode frames and transparent runners, and is sealed by a silicone pad. Combined with an aqueous gelatin solution with the same dynamic viscosity as the electrolyte, and add TiO2 to make its color white, making it easy to intuitively observe the flow of the electrolyte.
It realizes intuitive observation of the flow and distribution of electrolyte inside the stack, can quickly identify the dead zone and uneven distribution of the flow, promote the optimization of the stack structure, improve the performance of the stack, and saves time and cost of design and assembly.
Smart Images
Figure CN119994132A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of liquid flow batteries, and in particular to a visible transparent liquid flow battery stack that does not require charging or discharging. Background Art
[0002] Liquid flow battery is an energy storage technology that works by generating electrical energy based on chemical reactions. During the battery charging process, the chemical reaction converts the stored energy into electrical energy and generates a voltage between the electrodes; during the discharge process, the battery releases the stored energy, the chemical reaction reverses, and the electrical energy is converted into chemical energy. The biggest difference between liquid flow batteries and other batteries is that their electrolytes exist in the form of fluids and can be circulated through an external flow system. This feature makes liquid flow batteries widely used in many industries such as energy storage, electricity, aerospace, and transportation.
[0003] The stack structure is the core component of the flow battery, and its design and preparation have a crucial impact on the performance of the flow battery. Most of the known flow battery stack end plates are made of structural steel, and the electrode frame is mostly made of injection-molded and moldable engineering plastics. At the same time, the flow battery stack needs to be connected to a liquid storage tank, a magnetic pump, a pipeline, a BMS battery management system, a PCS energy storage converter, etc. to circulate the electrolyte and charge and discharge the stack. Before designing and assembling the flow battery stack, most simulation software such as Ansys, Comsol, and Matlab are used to simulate the flow of electrolyte in the electrode frame, flow channel, and electrode, but the software calculation results are normalized and ignore too many unpredictable problems in actual assembly. The simulation results are often very different from the actual situation after the stack is assembled and tested. The simulation results are normalized and stable, but when the flow battery stack is fed with electrolyte, the stack has "gas storage", which will cause a large number of bubbles in the electrode frame and flow channel that cannot be discharged. On the other hand, the roughness of the machining surface of the flow channel and the electrode frame will be greatly affected by manual and machine work. For example, the gas storage inside the flow channel, the cyclone formed inside the electrode frame, and the stack inlet pressure cannot be intuitively reflected in the software, which leads to inconsistency between the results of the design phase and the performance of the actual stack test.
[0004] At present, the optimization and innovation methods of flow battery stacks are relatively traditional. The potential technology is to use a certain stack as a benchmark and compare the performance by adjusting one of the factors such as the electrode frame structure, flow channel structure, electrode porosity, electrolyte viscosity, temperature, etc., while keeping other factors unchanged. Developing a transparent flow battery stack that can be visually operated without charging and discharging is of great significance to improving the performance and maintainability of flow batteries. Summary of the invention
[0005] In order to solve the above technical problems, the present invention provides a visual transparent liquid flow battery stack that does not require charging and discharging, and the technical solution is as follows:
[0006] A visual transparent liquid flow battery stack that does not require charging and discharging. The transparent stack includes a transparent end plate and a transparent electrode frame. The hard contact part between the transparent end plate and the transparent electrode frame is sealed with a silicone pad, and the remaining parts are fixedly connected with fasteners. The electrode area is provided with a liquid inlet, a liquid outlet and a transparent flow channel.
[0007] During the test, the transparent battery stack is connected to the magnetic pump and the liquid storage tank by pipes in sequence.
[0008] Furthermore, the liquid storage barrel is filled with a gelatin aqueous solution having the same dynamic viscosity as the electrolyte.
[0009] Furthermore, a certain proportion of TiO2 is added to the gelatin aqueous solution, and the final mass fraction of gelatin is 11-15%.
[0010] Furthermore, the preparation method of the gelatin aqueous solution is: gradually add gelatin solid particles into hot water and stir until completely dissolved and then cool to room temperature, and finally test the dynamic viscosity to be the same as the electrolyte used in the existing battery stack.
[0011] Furthermore, the transparent end plate, the transparent electrode frame and the transparent flow channel are all made of highly transparent acrylic or PC board materials.
[0012] Preferably, the transparent end plate, the transparent electrode frame and the transparent flow channel are made of highly transparent acrylic plates.
[0013] Furthermore, the silicone pad is an ultra-thin and highly light-transmitting silicone pad.
[0014] Compared with the prior art, the present invention has the following beneficial effects:
[0015] The device of the present invention is used to test the fluidity of the electrode frame and the flow field liquid, whether there are dead zones and places where the liquid flows unevenly, and is used for secondary prediction and verification between theoretical calculations, simulations and actual assembly, making the design more accurate and saving a lot of time and manpower costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a schematic diagram of the structure of the electrode side of the transparent battery stack;
[0017] Figure 2 This is a schematic diagram of the flow channel side structure of the transparent battery stack;
[0018] Figure 3 It is a schematic diagram of the transparent battery stack system;
[0019] Figure 4 This is a schematic diagram of the real-time flow of electrolyte in the channel in the third second after the magnetic pump is started;
[0020] Figure 5 This is a schematic diagram of the real-time flow of electrolyte in the channel at the seventh second after the magnetic pump is started;
[0021] Figure 6 It is a schematic diagram of the real-time flow of electrolyte in the channel after the flow is stabilized;
[0022] Figure 7 This is a schematic diagram of the electrolyte distribution in the electrode area after the flow stabilizes;
[0023] Figure 8 This is a schematic diagram of the real-time flow of electrolyte in the channel in the third second after the magnetic pump is started;
[0024] Fig. 9 This is a schematic diagram of the real-time flow of electrolyte in the channel at the seventh second after the magnetic pump is started;
[0025] Fig.10 It is a schematic diagram of the real-time flow of electrolyte in the channel after the flow is stabilized;
[0026] Fig.11 This is a schematic diagram of the electrolyte distribution in the electrode area after the flow stabilizes.
[0027] Among them: 1. transparent end plate, 2. transparent electrode frame, 3. fastener, 4. liquid inlet, 5. liquid outlet, 6. electrode area, 7. transparent flow channel, 8. transparent battery stack, 9. liquid storage barrel, 10. magnetic pump. DETAILED DESCRIPTION
[0028] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the examples, but the content of the present invention is not limited to the following examples. Unless otherwise specified, the experimental methods used in the present invention are conventional methods, and the experimental equipment, materials, reagents, etc. used can be purchased from chemical companies.
[0029] The present invention is a new type of battery stack that can significantly improve the performance of liquid flow battery stacks. A transparent battery stack is designed that does not require charging and discharging, and only requires one section to be assembled, without the need to assemble the entire battery stack, so that the internal structure of the battery stack and the flow of electrolyte can be intuitively observed. The flow state of each section of the all-vanadium liquid flow battery is basically the same, so only one section needs to be assembled to reflect the flow state of the electrolyte in each section of the entire battery stack. Different battery stacks have different numbers of sections, ranging from 30 sections, 36 sections, 42 sections, and 48 sections.
[0030] Important components in the present invention, such as electrode frames, end plates, and flow field structures, are all made of highly transparent acrylic or PC board materials. The stack is sealed by a rubber pad, and the hard-hard contact part between the transparent end plate 1 and the transparent electrode frame 2 is sealed with a silicone pad to prevent liquid leakage. The sealing material is an ultra-thin highly transparent silicone pad. The present invention can replace electrode frames and flow fields with different flow channel structures, and the smooth flow area and the dead flow area are clear at a glance, so as to intuitively evaluate and improve the stack structure in a targeted manner.
[0031] In addition, since the current vanadium liquid flow battery stack electrolyte uses V 3+ With VO 2+ The blue-green electrolyte with mixed valence states, if the vanadium sulfate electrolyte is pumped into the battery stack through a high-lift magnetic pump, the color of the electrolyte and the black electrode are very close, and it is impossible to visually observe the uniformity of the electrolyte flowing in the electrode. In order to be more intuitive and convenient to observe, for the present invention, a gelatin aqueous solution with the same dynamic viscosity as the electrolyte is developed at the same time, and a certain proportion of TiO2 is added to the gelatin aqueous solution to make its color more intuitive white. The gelatin aqueous solution purchases gelatin solid particles, gradually adds hot water to stir until completely dissolved, and then cools to room temperature. Finally, the dynamic viscosity is tested to be similar to the electrolyte used in the existing battery stack. The gelatin concentration is 11-15%. If the concentration exceeds this range, the viscosity will be too low, or the viscosity will be too high to flow.
[0032] In summary, this kind of battery stack whose internal structure and liquid flow can be observed intuitively from the outside of the battery stack, and 5 electrode frames with different flow channel structures are assembled by combining fine carving technology, and the liquid flow battery stack products are upgraded by the present invention. The flow of electrolyte can be observed intuitively from the outside, and the speed of the smooth flow area and the dead flow area can be adjusted to balance them. This battery stack pre-evaluates the rationality of the electrode frame, flow channel, and overall structure, which not only reduces the probability of failure in battery stack development, but also greatly shortens the assembly time because only one section needs to be assembled, saving a lot of material costs and precious time in the experimental stage.
[0033] The design principle of the present invention is as follows:
[0034] 1. System composition:
[0035] It includes a transparent battery stack 8, two magnetic pumps 10, two liquid storage barrels 9, and a number of pipeline valves. The two sets of structures are symmetrical face to face, and only half of them need to be assembled. Figure 3 shown.
[0036] 2. Stack materials and processing methods:
[0037] In this embodiment, the transparent end plate 1, the transparent electrode frame 2, and the transparent flow channel 7 are all made of a highly transparent acrylic plate that is finely carved.
[0038] 3. Application method:
[0039] The liquid storage barrel 9 of the present invention is filled with a fluid with a dynamic viscosity similar to that of the electrolyte. After the magnetic pump 10 pumps the electrolyte into the transparent battery stack 8, the flow of the fluid in the electrode frame and the flow channel can be observed, and the distribution of the electrolyte on the electrode side of the battery stack can be observed at the same time (without charging and discharging). See Example 1 and Comparative Example 1 for practical problems that can be solved by the present invention.
[0040] Example 1 Flow of electrolyte in the transparent battery stack of the present invention
[0041] pass Figure 4 to Figure 7 Visual observation shows that for product A battery stack, after the flow stabilizes, there is gas accumulation at the top of many flow channels. This phenomenon is that when the electrolyte flows in a narrow channel, it not only has to overcome the friction resistance of the inner wall of the channel, but also has to overcome the gravity of the liquid itself. In addition, due to the unreasonable design of the electrode frame, not only the amount of liquid supplied in each channel is different, and many flow channels cannot be filled with electrolyte, but also the flow and distribution of the electrolyte in the electrode area are extremely uneven. This unevenness will be the main reason for the large polarization internal resistance of the battery stack.
[0042] Comparative Example 1
[0043] By assembling the transparent battery stack 8, it can be found that the problem in Example 1 is that the design of the electrode frame and the flow channel is unreasonable. By redesigning and optimizing the electrode frame and increasing the width between the flow channels, the problems of flow dead zones and gas accumulation in the flow channels can be greatly reduced.
[0044] It can be seen from Example 1 and Comparison 2 that the present invention can intuitively observe the unreasonable problems or problems that need to be optimized inside the A battery stack. Targeted adjustments can significantly improve the structural problems, which not only balances the distribution of the electrolyte and reduces the polarization internal resistance of the battery stack, but also significantly improves the performance of the battery stack.
[0045] The transparent battery stack of the present invention that does not require charging and discharging solves the following problems of the traditional flow battery stack:
[0046] ① After the traditional liquid flow battery stack is assembled, it is impossible to understand the operation of the electrolyte inside the stack, and it is impossible to understand the distribution of the electrolyte in the electrode area. When designing the stack, it can only rely on traditional Ansys, Comsol, Matlab and other software simulation to improve the structure.
[0047] ② The transparent battery stack of the present invention only needs to assemble one section to evaluate the flow and distribution of the electrolyte, avoiding the long spare parts preparation period and initial performance test time required for assembling dozens of experimental stacks, while saving experimental costs.
[0048] ③ The present invention does not require charging and discharging, which greatly reduces the risk of electric shock for experimenters during work.
[0049] The main reason for the poor performance of the battery stack is the concentration polarization caused by the uneven distribution of the electrolyte (concentration polarization is due to the uneven distribution of the electrolyte in the electrode area or the existence of dead zones, which leads to uneven electrolyte concentration and causes potential difference. This part of the potential difference causes a large proportion of the internal resistance of the battery stack, thus affecting the performance of the battery stack). The present invention can intuitively observe the flow and distribution of the electrolyte inside the battery stack, and can make timely structural improvements according to the observed adverse conditions at any time. The improvement of the traditional liquid flow battery stack structure is through the assembly of the test battery stack. After the battery stack is assembled, it is necessary to test various original data such as initial performance, single voltage range, OCV range, self-discharge, etc., and guess the cause of poor performance by analyzing cumbersome data.
[0050] The transparent battery stack of the present invention can continuously improve the battery stack structure by observing the flow and distribution of the electrolyte until it is satisfactory. The traditional assembly test battery stack requires material procurement, spare parts processing, assembly, testing, etc., which takes 5 to 6 months. The transparent battery stack of the present invention can save a lot of time for the design and improvement of the battery stack structure and the expensive cost of assembling the experimental battery stack, providing important technical support for technological research and development.
[0051] Application Example 1
[0052] By assembling a transparent battery stack 8 and connecting the magnetic pump 10 and the liquid storage tank 9, the flow and distribution of the electrolyte inside the battery stack can be observed intuitively. In this way, the electrode frame structure can be improved until it is satisfactory, avoiding the long-term preparation and processing of battery stack spare parts, avoiding the high experimental costs and the tedious analysis of raw data to guess the reasons for the poor performance of the battery stack. 2 At a current density of , the energy efficiency is 80.6%, but there is still a lot of room for optimization of the battery stack structure. Through the transparent battery stack of the present invention, 5 electrode frame structures have been changed from initial testing to finalization. At present, the upgraded battery stack has an energy efficiency of 83.6% while keeping the current density unchanged. The energy efficiency has been improved by 3%. This 3% improvement usually takes 1 to 2 years of research and development time to achieve.
[0053] The transparent battery stack of the present invention provides strong support for the technological development of the liquid flow battery energy storage industry.
[0054] Table 1 Comparison of test data of stacks of Example 1 and Comparative Example 1
[0055] CE(%) EE(%) VE(%) Example 1 96.4 80.6 83.6 Comparative Example 1 96.7 83.6 86.5
[0056] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A visual transparent liquid flow battery stack that does not require charging and discharging, characterized in that: The transparent battery stack (8) comprises a transparent end plate (1) and a transparent electrode frame (2). The hard-hard contact portion between the transparent end plate (1) and the transparent electrode frame (2) is sealed with a silicone pad, and the remaining portion is fixedly connected with a fastener (3). The electrode area (6) is provided with a liquid inlet (4), a liquid outlet (5) and a transparent flow channel (7).
2. The transparent liquid flow battery stack without charging and discharging according to claim 1 is characterized in that: During testing, the transparent battery stack (8) is connected to the magnetic pump (10) and the liquid storage tank (9) in sequence through pipelines.
3. The visual transparent liquid flow battery stack without charging and discharging according to claim 2 is characterized in that: The liquid storage barrel (9) is filled with a gelatin aqueous solution having the same dynamic viscosity as that of the electrolyte.
4. The transparent liquid flow battery stack without charging or discharging according to claim 3 is characterized in that: A certain proportion of TiO2 is added to the gelatin aqueous solution, and the final gelatin mass fraction is 11-15%.
5. The visual transparent liquid flow battery stack without charging and discharging according to claim 3 is characterized in that: The preparation method of the gelatin aqueous solution is: gradually add gelatin solid particles into hot water and stir until completely dissolved and then cool to room temperature. Finally, the dynamic viscosity is tested and it is the same as the electrolyte used in the existing battery stack.
6. The visual transparent liquid flow battery stack without charging and discharging according to claim 1 is characterized in that: The transparent end plate (1), the transparent electrode frame (2) and the transparent flow channel (7) are all made of highly transparent acrylic or PC board materials.
7. The visual transparent liquid flow battery stack without charging and discharging according to claim 1 is characterized in that: The transparent end plate (1), the transparent electrode frame (2) and the transparent flow channel (7) are made of highly transparent acrylic plates.
8. The visual transparent liquid flow battery stack without charging and discharging according to claim 1 is characterized in that: The silicone pad is an ultra-thin and highly light-transmitting silicone pad.