Device and method for testing distribution of flow battery electrolyte on surface of carbon felt

Abstract

The invention belongs to the technical field of electrolyte detection, and particularly relates to a device and method for testing distribution of a flow battery electrolyte on the surface of a carbon felt.The device for testing distribution of the flow battery electrolyte on the surface of the carbon felt.The device comprises a detection cavity, a circulating pump, a cooling water bath kettle, a heating water bath kettle and a thermal infrared imager; a second liquid storage tank is installed at the top of the heating water bath kettle, the output end of the detection cavity is connected with an input end pipeline of a circulating pump, an output end pipeline of the circulating pump is connected with a control valve, and two input ends of the control valve are connected with input end pipelines of the first liquid storage tank and the second liquid storage tank. Through cooperation of the detection cavity, the thermal infrared imager, the circulating pump and the defoaming mechanism, direct and real-time detection of electrolyte distribution is realized by utilizing temperature field change generated by circulation of cold and hot electrolyte and combining a temperature sensor and thermal infrared image analysis, and the problems of indirect and inaccurate detection in the prior art are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrolyte detection, and in particular relates to testing equipment and a method for testing the distribution of electrolyte of a flow battery on a carbon felt surface. Background Art

[0002] With the development of society, liquid flow batteries, as a long cycle life and high safety energy storage technology, are widely used in renewable energy storage, grid frequency and peak regulation and other fields. They achieve energy conversion through the redox reaction of electrolyte on the surface of carbon felt. Therefore, the uniformity of electrolyte distribution on the electrode surface directly affects the energy density, power density and efficiency of the battery.

[0003] However, in the existing technology, due to the internal sealing of the liquid flow battery, it is difficult to directly observe the flow characteristics of the electrolyte on the carbon felt surface. It mainly relies on macroscopic fluid mechanics model simulation or indirect means such as flow sensors and pressure drop measurements to infer. It lacks intuitive and real-time surface distribution information and cannot accurately reflect the microscopic distribution of the electrolyte in the microporous structure of the carbon felt, making it difficult to effectively optimize the battery design and affecting the improvement of battery performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a test device and method for the distribution of liquid flow battery electrolyte on the carbon felt surface, which solves the problem in the prior art that the electrolyte distribution detection is indirect, inaccurate, lacks real-time performance, and is difficult to meet the requirements of battery optimization design.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: providing a test device for the distribution of liquid flow battery electrolyte on the surface of carbon felt, comprising a detection chamber, a circulation pump, a refrigeration water bath, a heating water bath and an infrared thermal imager, wherein a liquid storage tank 1 is installed inside the refrigeration water bath, a liquid storage tank 2 is installed on the top of the heating water bath, the output end of the detection chamber is connected to the input end pipe of the circulation pump, the output end pipe of the circulation pump is connected to a control valve, the two input ends of the control valve are connected to the input end pipes of the liquid storage tank 1 and the liquid storage tank 2, the output end pipe of the liquid storage tank 2 is connected to a defoaming mechanism, the pipe at the output end of the liquid storage tank 1 and the pipe at the output end of the defoaming mechanism are connected to the input pipe of the detection chamber, and an anti-backflow mechanism is installed in the pipe at the output end of the liquid storage tank 1 and the pipe at the output end of the defoaming mechanism;

[0006] The detection cavity includes a base plate, a shell, a plywood, a carbon felt, a polyethylene sheet and an infrared temperature measuring hole. The front end of the base plate is bolted with the shell. Two stacked plywoods are installed between the base plate and the shell. Carbon felt and a temperature sensor are installed between the two plywoods. A polyethylene sheet is embedded in the front end of the plywood. Nine infrared temperature measuring holes distributed in a rectangular shape are opened on the outer wall of the shell.

[0007] The infrared thermal imager is located at the front end of the housing;

[0008] A flow controller is installed on the pipeline between the output end of the circulation pump and the input end of the control valve.

[0009] Optionally, the detection cavity further includes an outflow groove, a mounting groove and an inflow groove, and the opposite surfaces of the two splints are provided with an outflow groove, a mounting groove and an inflow groove, the outflow groove is located above the mounting groove and is connected to the mounting groove, the inflow groove is located below the mounting groove and is connected to the mounting groove, and the carbon felt is located between the two mounting grooves.

[0010] Optionally, a liquid outlet pipe and a liquid inlet pipe are fixedly connected to the side wall of the shell, the liquid outlet pipe corresponds to the port position of the output end of the outflow trough, the liquid inlet pipe corresponds to the port position of the input end of the inflow trough, the output end of the liquid outlet pipe is connected to the input end pipeline of the circulation pump, and the input end of the liquid inlet pipe is connected to the output end pipeline of the liquid storage tank and the defoaming mechanism.

[0011] Optionally, a sealing ring is fixedly installed between the base plate and the shell, and a bolt connecting the base plate and the shell passes through the sealing ring.

[0012] Optionally, the control valve includes a shell 1, a ball valve, a flow groove and a turning handle. The shell 1 is fixedly connected between the output pipe of the circulation pump and the input pipes of liquid storage tank 1 and liquid storage tank 2. A ball valve is movably installed inside the shell 1. The flow groove is fixedly connected inside the ball valve. The top of the ball valve is fixedly connected to the turning handle. The rotational resistance between the turning handle and the shell 1 is greater than the flow thrust of the liquid through the flow groove.

[0013] Optionally, the defoaming mechanism includes a tank body, a conical groove and a thin flow channel, the tank body is located at the front end of the liquid storage tank 2, the liquid inlet pipe of the tank body is fixedly connected between the output end of the liquid storage tank 2 and the top of the outer wall of the tank body, the liquid outlet pipe of the tank body is fixedly connected to the bottom of the outer wall of the tank body away from the liquid inlet pipe, and is connected to the inner cavity of the tank body and the input end of the liquid inlet pipe, the inner wall of the tank body liquid inlet pipe is provided with a conical groove and a thin flow channel, the inner diameter of the tank body liquid inlet pipe is five times the inner diameter of the thin flow channel, and the thin flow channel is connected to the inner cavity of the tank body.

[0014] Optionally, the defoaming mechanism also includes a mounting cylinder, a hydrophobic membrane, an activated carbon filter block, a sealing cover and an exhaust pipe. The mounting cylinder is fixedly connected to the top of the tank body, a hydrophobic membrane is fixedly installed between the mounting cylinder and the tank body, an activated carbon filter block is fixedly installed inside the mounting cylinder, a sealing cover is threadedly installed on the top of the mounting cylinder, and an exhaust pipe is fixedly connected to the top of the sealing cover.

[0015] Optionally, the anti-backflow mechanism includes a shell 2, a spring and a baffle. The shell 2 is installed in the pipe at the output end of the liquid storage tank 1 and the pipe at the output end of the defoaming mechanism. The spring is fixedly installed inside the shell 2, and the baffle is slidably installed inside the shell 2. The end of the spring is fixedly connected to the outer wall of the thin flow channel.

[0016] A method for testing the distribution of a flow battery electrolyte on a carbon felt surface, using any of the above-described testing devices for testing the distribution of a flow battery electrolyte on a carbon felt surface, specifically comprises the following steps:

[0017] S1. Equipment Assembly and Preparation

[0018] S1-1. Install the carbon felt in the detection chamber;

[0019] S1-2. Electrolyte is added to the liquid storage tank 1 and the liquid storage tank 2 respectively;

[0020] S1-3. Place a liquid storage tank in a refrigerated water bath and place the liquid storage tank two in a hot water bath;

[0021] S1-4. Turn on the cooling water bath and the hot water bath to keep the electrolyte temperature in the reservoir tank constant at 20°C ± 2°C and the electrolyte temperature in the reservoir tank two constant at 35°C ± 2°C.

[0022] S1-5. Adjust the infrared thermal imager so that it faces the infrared temperature measurement hole of the detection chamber and connect it to the computer;

[0023] S2. System wetting and exhaust

[0024] S2-1. Operate the control valve to connect the circulation pump and the liquid storage tank;

[0025] S2-2 start the circulation pump and flow controller, control the low-temperature electrolyte to flow through the detection chamber at a first flow rate, the first flow rate is 50 ~ 300mL / min, continue to circulate until the carbon felt is fully wetted and the gas in the system is exhausted;

[0026] S2-3. Monitor the temperature of the carbon felt by the temperature sensor between the two splints until the temperature stabilizes at 20°C ± 0.5°C;

[0027] S3. Hot electrolyte injection and data acquisition

[0028] S3-1. Operate the control valve to switch the circulating pump and the liquid storage tank 2;

[0029] S3-2. When the high-temperature electrolyte is discharged from the second storage tank, the bubbles in the high-temperature electrolyte are removed by the degassing mechanism, and the electrolyte is ensured to flow in one direction by the anti-backflow mechanism;

[0030] S3-3. The high-temperature electrolyte is controlled by a flow controller to flow through the detection chamber at a flow rate of 90 mL / min;

[0031] S3-4. Record the switching time as the initial time, and perform the following operations synchronously from the initial time:

[0032] a. Use an infrared thermal imager to continuously collect infrared thermal images of the carbon felt surface in the test cavity;

[0033] b. Using a temperature sensor to continuously record the temperature change over time at one or more selected test points on the carbon felt;

[0034] S4. Data Analysis

[0035] S4-1. Based on the infrared thermal image collected in step S3, the distribution area of the electrolyte on the carbon felt surface is determined by calculating the spatial gradient of the temperature field, wherein the area with a temperature gradient greater than 2°C / cm is determined to be an electrolyte-rich area, and the area with a temperature gradient less than 0.5°C / cm is determined to be an electrolyte-poor area;

[0036] S4-2. Based on the temperature-time data recorded in step S3, a linear fit is performed on the temperature curve of each test point. The fitting slope is used as the heating rate. The test points with a heating rate greater than 0.3°C / s are determined to be in the high fluidity region, and the test points with a heating rate less than 0.1°C / s are determined to be in the low fluidity region.

[0037] S4-3. Evaluate the uniformity of electrolyte flow based on the distribution ratio of electrolyte-rich and electrolyte-poor areas and the proportion of high-mobility and low-mobility areas. If the area ratio of electrolyte-poor areas is less than 10% and the proportion of low-mobility areas is less than 15%, it is judged to be uniformly distributed.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The test equipment for testing the distribution of liquid flow battery electrolyte on the carbon felt surface of the present invention is provided with a detection chamber, an infrared thermal imager and a flow controller. When in use, the plywood, carbon felt, polyethylene sheet and other structures inside the detection chamber form a sealed test space. The low infrared absorption characteristics of the polyethylene sheet ensure that the infrared thermal imager can accurately collect the temperature field distribution on the carbon felt surface. As cold (20°C) and hot (35°C) electrolytes alternately flow through the detection chamber in a circulation system, the infrared thermal imager records the temperature field changes in real time and reflects the electrolyte distribution through the temperature gradient. For example, when a 4cm×4cm carbon felt is tested at a flow rate of 90mL / min, the infrared thermal image can clearly show the temperature rise rate of each test point (P1>P2>P3>P5>P4), thereby inferring the ion exchange rate, realizing direct and real-time detection of the electrolyte distribution, providing accurate data support for battery optimization, and improving the accuracy and reliability of detection.

[0040] The test equipment for the distribution of liquid flow battery electrolyte on the carbon felt surface of the present invention is provided with a defoaming mechanism. The electrolyte discharged from the second liquid storage tank enters the fine flow channel through the conical groove, and the sudden change of the tube diameter is used to break large bubbles into small bubbles. The small bubbles float to the top after entering the tank body with the electrolyte. The hydrophobic membrane on the top of the tank body only allows gas to pass through. The gas is purified by the activated carbon filter block and then discharged from the exhaust pipe, while the electrolyte flows out from the bottom of the tank body. The bubbles in the electrolyte can be effectively removed, and the bubbles are prevented from interfering with the temperature field measurement, thereby ensuring the stability and accuracy of the detection data and improving the credibility of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0042] Figure 1 This is a schematic structural diagram from a first perspective of a testing device for the distribution of electrolyte on a carbon felt surface in a flow battery according to the present invention;

[0043] Figure 2 A schematic structural diagram from a second perspective of a testing device for the distribution of electrolyte on a carbon felt surface in a flow battery according to the present invention;

[0044] Figure 3 This is a schematic diagram of the explosion structure of the detection chamber of the test equipment for the distribution of the electrolyte of the flow battery on the surface of the carbon felt of the present invention;

[0045] Figure 4 for Figure 3 A in the middle is an enlarged structural diagram;

[0046] Figure 5 for Figure 3 Structural diagram from another perspective;

[0047] Figure 6 Schematic diagram of the explosion structure of the control valve of the test equipment for the distribution of the electrolyte of the flow battery on the surface of the carbon felt of the present invention;

[0048] Figure 7 This is an enlarged structural schematic diagram of the defoaming mechanism and the backflow prevention mechanism of the test equipment for the distribution of the electrolyte of the flow battery on the surface of the carbon felt of the present invention;

[0049] Figure 8 for Figure 7 Schematic diagram of the enlarged structure at B in the middle;

[0050] Figure 9 for Figure 7 Schematic diagram of the enlarged structure at C in the middle;

[0051] Figure 10 This is a schematic diagram of the distribution structure of infrared temperature measuring holes on the shell of the test equipment for the distribution of the electrolyte of the flow battery on the surface of the carbon felt of the present invention;

[0052] Figure 11 This is the infrared thermal image and temperature distribution diagram of the present invention when the carbon felt area is 4cm×4cm and the electrolyte flow rate is 90mL / min;

[0053] Figure 12 The infrared thermal image and temperature distribution diagram of the present invention are shown in FIG. 1 , when the carbon felt area is 10 cm×10 cm and the electrolyte flow rate is 846 mL / min.

[0054] Figure 13 This is a graph showing the temperature and time changes at different flow rates for a carbon felt having an area of 10 cm×10 cm according to the present invention.

[0055] In the figure: 1. Detection chamber; 101. Base plate; 102. Housing; 103. Clamping plate; 104. Carbon felt; 105. Polyethylene sheet; 106. Outflow trough; 107. Mounting trough; 108. Inflow trough; 109. Liquid outlet pipe; 110. Liquid inlet pipe; 112. Sealing ring; 113. Infrared temperature measuring hole; 2. Circulation pump; 3. Refrigeration water bath; 4. Heating water bath; 5. Liquid storage tank 1; 6. Liquid storage tank 2; 7. Infrared thermal imager; 8. Flow control Controller; 9. Control valve; 901. Shell 1; 902. Ball valve; 903. Flow trough; 904. Turning handle; 10. Defoaming mechanism; 1001. Tank body; 1002. Conical trough; 1003. Fine flow channel; 1004. Mounting cylinder; 1005. Hydrophobic membrane; 1006. Activated carbon filter block; 1007. Sealing cover; 1008. Exhaust pipe; 11. Backflow prevention mechanism; 1101. Shell 2; 1102. Spring; 1103. Baffle. DETAILED DESCRIPTION

[0056] 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 with reference to 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.

[0057] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0058] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0059] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0060] Example 1

[0061] Reference Figure 1-13 , a test device for the distribution of liquid flow battery electrolyte on the surface of carbon felt, including a detection chamber 1, a circulation pump 2, a refrigeration water bath 3, a heating water bath 4 and an infrared thermal imager 7, a liquid storage tank 1 5 is installed inside the refrigeration water bath 3, a liquid storage tank 2 6 is installed on the top of the heating water bath 4, the output end of the detection chamber 1 is connected to the input end pipe of the circulation pump 2, the output end pipe of the circulation pump 2 is connected to a control valve 9, the two input ends of the control valve 9 are connected to the input end pipes of the liquid storage tank 1 5 and the liquid storage tank 2 6, the output end pipe of the liquid storage tank 2 6 is connected to a defoaming mechanism 10, the pipe at the output end of the liquid storage tank 1 5 and the pipe at the output end of the defoaming mechanism 10 are connected to the input pipe of the detection chamber 1, and an anti-backflow mechanism 11 is installed in the pipe at the output end of the liquid storage tank 1 5 and the pipe at the output end of the defoaming mechanism 10.

[0062] When in use, the refrigeration water bath 3 and the heating water bath 4 maintain the electrolyte temperature of the liquid storage tank 1 5 and the liquid storage tank 2 6 at 20°C and 35°C respectively, forming a temperature difference to reflect the flow distribution through thermal imaging; the circulation pump 2 drives the electrolyte circulation, and the flow controller 8 monitors the flow rate in real time and feeds back to the circulation pump 2 to ensure the stability of the flow rate; the control valve 9 realizes the switching of the electrolyte output.

[0063] The detection chamber 1 includes a substrate 101, an outer shell 102, a splint 103, a carbon felt 104, a polyethylene sheet 105 and an infrared temperature measuring hole 113. The outer shell 102 is installed on the front bolt of the substrate 101. Two stacked splints 103 are installed between the substrate 101 and the outer shell 102. The carbon felt 104 and a temperature sensor are installed between the two splints 103. The temperature sensor model is a PT100 armored coupler instrument patch type. The polyethylene sheet 105 is embedded in the interior of the front splint 103. Nine infrared temperature measuring holes 113 distributed in a rectangular shape are opened on the outer wall of the outer shell 102.

[0064] When in use, the base plate 101 and the housing 102 are fixed by bolts, and the sealing ring 112 ensures that the detection chamber is sealed to prevent electrolyte leakage. The mounting groove 107 between the two clamping plates 103 is used to fix the carbon felt 104. The inflow groove 108 and the outflow groove 106 constitute the electrolyte flow channel to simulate the actual battery flow field; the low infrared absorption characteristics of the polyethylene sheet 105 allow the infrared thermal imager 7 to capture the surface temperature of the carbon felt 104 through it. The nine infrared temperature measuring holes 113 correspond to the nine test points on the surface of the carbon felt 104 ( Figure 12 P1-P9 in ), realizing synchronous acquisition of multi-point temperature field.

[0065] The infrared thermal imager 7 is located at the front end of the housing 102 .

[0066] Infrared thermal imager 7, model FLIRT640, has a temperature measurement range of -20°C to 150°C, a resolution of 640×480, and a frame rate of 30Hz. It faces infrared temperature measurement port 113 in housing 102 and connects to a computer via a USB 3.0 interface to collect real-time temperature data on the surface of carbon felt 104. During use, infrared thermal imager 7 captures a real-time thermal image of the carbon felt 104 surface through infrared temperature measurement port 113. The temperature sensor simultaneously records the temperature and time data at each test point. Flow controller 8 converts the flow rate into an electrical signal and feeds it back to circulation pump 2, achieving closed-loop flow control and ensuring stable experimental conditions.

[0067] A flow controller 8 is installed on the pipeline between the output end of the circulation pump 2 and the input end of the control valve 9.

[0068] The flow controller 8 is model FC-300, with an accuracy of ±0.5%, which monitors the flow rate data in real time and feeds back the flow rate data to the circulation pump 2 to form a closed-loop control.

[0069] Compared with the prior art, the testing equipment and method for the distribution of electrolyte in a flow battery on a carbon felt surface provided by the present invention solve the problems in the prior art of indirect, inaccurate and lacking real-time detection of electrolyte distribution, which makes it difficult to meet the requirements of battery optimization design.

[0070] The detection chamber 1 also includes an outflow groove 106, a mounting groove 107 and an inflow groove 108. The opposite surfaces of the two splints 103 are provided with an outflow groove 106, a mounting groove 107 and an inflow groove 108. The outflow groove 106 is located above the mounting groove 107 and is connected to the mounting groove 107. The inflow groove 108 is located below the mounting groove 107 and is connected to the mounting groove 107. The carbon felt 104 is located between the two mounting grooves 107.

[0071] During use, the electrolyte enters from the inlet groove 108, flows through the carbon felt 104, and is discharged from the outlet groove 106. The flow channel structure is consistent with the actual battery, ensuring the authenticity of the test environment; the installation groove 107 limits the compression rate of the carbon felt 104, simulating the compaction state inside the battery, and avoiding test deviations caused by structural differences.

[0072] The side wall of the shell 102 is fixedly connected with a liquid outlet pipe 109 and a liquid inlet pipe 110. The liquid outlet pipe 109 corresponds to the port position of the output end of the outflow groove 106, and the liquid inlet pipe 110 corresponds to the port position of the input end of the inflow groove 108. The output end of the liquid outlet pipe 109 is connected to the input end pipeline of the circulation pump 2, and the input end of the liquid inlet pipe 110 is connected to the output end of the liquid storage tank 5 and the output end pipeline of the defoaming mechanism 10.

[0073] When in use, the liquid inlet pipe 110 and the liquid outlet pipe 109 form an electrolyte circulation loop to ensure that the electrolyte continues to flow through the carbon felt 104. The port corresponds to the flow channel position to avoid flow stagnation caused by dead corners in the flow channel and ensure that the electrolyte is evenly covered on the surface of the carbon felt 104.

[0074] A sealing ring 112 is fixedly installed between the substrate 101 and the housing 102 , and bolts connecting the substrate 101 and the housing 102 pass through the sealing ring 112 .

[0075] The sealing ring 112 is deformed by the bolts and fills the gap between the substrate 101 and the housing 102 to form a liquid-tight seal, thereby preventing leakage of electrolyte from affecting the safety of the experiment and the accuracy of the data.

[0076] The control valve 9 includes a shell 901, a ball valve 902, a flow groove 903 and a turning handle 904. The shell 901 is fixedly connected between the output pipe of the circulation pump 2 and the input pipes of the liquid storage tank 5 and the liquid storage tank 2 6. The ball valve 902 is movably installed inside the shell 901. The flow groove 903 is fixedly connected inside the ball valve 902. The top of the ball valve 902 is fixedly connected to the turning handle 904. The rotational resistance between the turning handle 904 and the shell 901 is greater than the flow thrust of the liquid through the flow groove 903.

[0077] During use, the ball valve 902 is rotated by turning the handle 904, so that the flow groove 903 is aligned with the pipeline of the liquid storage tank 1 5 or the liquid storage tank 2 6 to realize the switching of hot and cold electrolytes; the resistance design prevents the ball valve 902 from rotating automatically due to liquid pressure, avoiding the invalidation of experimental data caused by the wrong switching of the flow path.

[0078] The defoaming mechanism 10 includes a tank body 1001, a tapered groove 1002 and a thin flow channel 1003. The tank body 1001 is located at the front end of the liquid storage tank 2 6. The liquid inlet pipe of the tank body 1001 is fixedly connected between the output end of the liquid storage tank 2 6 and the top of the outer wall of the tank body 1001. The liquid outlet pipe of the tank body 1001 is fixedly connected to the bottom of the outer wall of the tank body 1001 away from the liquid inlet pipe, and is connected to the inner cavity of the tank body 1001 and is connected to the input end of the liquid inlet pipe 110. The inner wall of the liquid inlet pipe of the tank body 1001 is provided with a tapered groove 1002 and a thin flow channel 1003. The inner diameter of the liquid inlet pipe of the tank body 1001 is five times the inner diameter of the thin flow channel 1003. The thin flow channel 1003 is connected to the inner cavity of the tank body 1001.

[0079] During use, the high-temperature electrolyte in the liquid storage tank 2 6 enters through the liquid inlet pipe, is first accelerated by the tapered groove 1002, and then further accelerated by the thin flow channel 1003 (the tube diameter is reduced by 5 times), cutting large bubbles into small bubbles; after the small bubbles enter the tank body 1001 with the electrolyte, they rise to the top due to buoyancy, and the electrolyte flows into the detection cavity 1 from the bottom liquid outlet pipe, realizing gas-liquid separation and preventing bubbles from interfering with temperature detection.

[0080] The defoaming mechanism 10 also includes a mounting cylinder 1004, a hydrophobic membrane 1005, an activated carbon filter block 1006, a sealing cover 1007 and an exhaust pipe 1008. The mounting cylinder 1004 is fixedly connected to the top of the tank body 1001. The hydrophobic membrane 1005 is fixedly installed between the mounting cylinder 1004 and the tank body 1001. The activated carbon filter block 1006 is fixedly installed inside the mounting cylinder 1004. The sealing cover 1007 is threadedly installed on the top of the mounting cylinder 1004, and the exhaust pipe 1008 is fixedly connected to the top of the sealing cover 1007.

[0081] During use, the gas in the bubbles at the top of the tank body 1001 enters the installation cylinder 1004 through the hydrophobic membrane 1005, and the activated carbon filter block 1006 adsorbs impurities in the gas. The purified gas is discharged through the exhaust pipe 1008 to avoid bubble residue or environmental pollution and ensure thorough defoaming.

[0082] The anti-backflow mechanism 11 includes a shell 2 1101, a spring 1102 and a baffle 1103. The shell 2 1101 is installed in the pipeline at the output end of the liquid storage tank 15 and the pipeline at the output end of the defoaming mechanism 10. The spring 1102 is fixedly installed inside the shell 2 1101, and the baffle 1103 is slidably installed inside the shell 2 1101. The end of the spring 1102 is fixedly connected to the outer wall of the thin channel 1003.

[0083] When the electrolyte flows in the forward direction, the liquid pressure pushes the baffle 1103 to compress the spring 1102, and the flow channel opens; if reverse flow occurs, the spring 1102 pushes the baffle 1103 to return to its original position, closing the flow channel to prevent the cold electrolyte in the liquid storage tank 1 5 from mixing with the hot electrolyte in the liquid storage tank 2 6, thereby avoiding temperature field interference and ensuring the authenticity and reliability of the test data.

[0084] A method for testing the distribution of a flow battery electrolyte on a carbon felt surface, using any of the above-mentioned testing devices for the distribution of a flow battery electrolyte on a carbon felt surface, specifically comprises the following steps:

[0085] S1. Equipment Assembly and Preparation

[0086] S1-1. The carbon felt 104 having an area of 4cm × 4cm is installed in the detection chamber 1 to ensure that it is in a compressed state in the detection chamber 1, simulating the actual installation conditions within the battery;

[0087] S1-2. Add electrolyte to the reservoir tank 5 and the reservoir tank 6, respectively, to provide hot and cold electrolytes for the circulation system to ensure that the experiment has sufficient test medium;

[0088] S1-3. The liquid storage tank 5 is placed in a refrigerated water bath 3, the liquid storage tank 6 is placed in a hot water bath 4, the electrolyte temperature is maintained constant by the water bath, to establish a stable temperature difference of 20 ℃ and 35 ℃, providing a basis for thermal imaging detection;

[0089] S1-4. Turn on the cooling water bath 3 and the hot water bath 4, so that the electrolyte temperature in the reservoir tank 5 is constant at 20 ℃, the electrolyte temperature in the reservoir tank 6 is constant at 35 ℃, precisely control the temperature to avoid temperature fluctuations leading to distortion of the thermal imaging data, ensuring the reliability of the temperature gradient;

[0090] S1-5 adjust the infrared thermal imager 7 so that it is facing the infrared temperature measuring hole 113 of the detection chamber 1 and connected to the computer to ensure that the infrared thermal imager 7 accurately captures the carbon felt 104 surface temperature signal, and records and stores thermal imaging data in real time by the computer for subsequent analysis;

[0091] S2. System wetting and exhaust

[0092] S2-1. Operate the control valve 9 to connect the circulating pump 2 and the liquid storage tank 5, so that the 20 ℃ low-temperature electrolyte enters the circulation system to prepare for subsequent hot electrolyte injection;

[0093] S2-2. Start the circulation pump 2 and the flow controller 8 to control the low-temperature electrolyte to flow through the detection chamber 1 at a first flow rate of 50 to 300 mL / min. Continuous circulation is performed until the carbon felt 104 is fully wetted and the gas in the system is exhausted. The low-temperature electrolyte flows to fill the pores of the carbon felt 104 and discharge the residual air in the system to avoid interference of bubbles on the electrolyte distribution detection. At the same time, ensure that the carbon felt 104 is completely wetted, simulating the actual operating state of the battery.

[0094] S2-3. The temperature of the carbon felt 104 is monitored by a temperature sensor between the two splints 103. When the temperature stabilizes at 20°C, confirm that the temperature of the carbon felt 104 is consistent with the low-temperature electrolyte, eliminating the impact of the initial temperature difference on subsequent thermal imaging to ensure a stable data baseline.

[0095] S3. Hot electrolyte injection and data acquisition

[0096] S3-1. Operate the control valve 9 to switch the circulating pump 2 and the liquid storage tank 6, so that the 35 ℃ high temperature electrolyte enters the detection chamber 1, and forms a heat exchange with the low temperature electrolyte on the surface of the carbon felt 104, and the temperature field changes reflect the electrolyte flow distribution;

[0097] S3-2. After the high-temperature electrolyte is discharged from the liquid storage tank 6, the bubbles in the high-temperature electrolyte are removed by the degassing mechanism 10 to avoid abnormal temperature fields caused by bubbles. The anti-backflow mechanism 11 ensures unidirectional flow of the electrolyte, preventing mixing of hot and cold electrolytes, ensuring that the temperature gradient truly reflects the flow state.

[0098] S3-3. The high-temperature electrolyte was controlled by the flow controller 8 at a flow rate of 90 mL / min flowing through the detection chamber 1, and the flow rate was adjusted to simulate different working conditions to study the effect of the flow rate on the electrolyte distribution;

[0099] S3-4. Record the switching time as the initial time, and perform the following operations synchronously from the initial time:

[0100] a. Using an infrared thermal imager 7 to continuously collect infrared thermal images of the surface of the carbon felt 104 in the detection chamber 1, the spatial distribution of the temperature field is recorded in real time, and the electrolyte-rich and depleted areas are visually displayed through the temperature gradient;

[0101] b. Using a temperature sensor to continuously record the temperature change data of one or more selected test points on the carbon felt 104 over time, the electrolyte fluidity is quantified by the slope of the temperature-time curve. A large slope indicates good fluidity, and vice versa.

[0102] S4. Data Analysis

[0103] S4-1. Based on the infrared thermal image acquired in step S3, the distribution area of the electrolyte on the surface of the carbon felt 104 is determined by calculating the spatial gradient of the temperature field. The area with a temperature gradient greater than 2°C / cm is determined to be an electrolyte-rich area, and the area with a temperature gradient less than 0.5°C / cm is determined to be an electrolyte-poor area. The uniformity of the electrolyte distribution on the surface of the carbon felt 104 is quantified to provide a basis for optimizing the battery flow path.

[0104] S4-2. Based on the temperature-time data recorded in step S3, a linear fit is performed on the temperature curve of each test point. The fitting slope is used as the heating rate. The test points with a heating rate greater than 0.3°C / s are determined to be in a high fluidity region, and the test points with a heating rate less than 0.1°C / s are determined to be in a low fluidity region. The flow state of the electrolyte is evaluated by kinetic parameters to identify the flow stagnation region.

[0105] S4-3. Evaluate the uniformity of electrolyte flow based on the distribution ratio of electrolyte-rich and electrolyte-poor areas and the proportion of high-mobility and low-mobility areas. If the area ratio of electrolyte-poor areas is less than 10% and the proportion of low-mobility areas is less than 15%, the flow is considered uniform. Establish a quantitative evaluation standard to provide reference performance indicators for liquid flow battery design.

[0106] Example 2

[0107] The difference between Example 2 and Example 1 is that the area of the detection carbon felt 104 is 10 cm×10 cm, the electrolyte flow rate is 846 mL / min, the low-temperature electrolyte temperature is constant at 20° C., and the high-temperature electrolyte temperature is constant at 35° C.

[0108] Difference after change: Figure 12 As shown in the figure, when the area of carbon felt 104 is increased to 10cm×10cm and the flow rate is increased to 846mL / min, the infrared thermal image shows that the temperature gradient of the edge area of the detection cavity 1 (such as P6 and P9) is significantly smaller than that of the central area, and the heating rate is slower. This is because the migration mechanism of the electrolyte inside the carbon felt 104 changes from diffusion-dominated to turbulent effect-dominated at high flow rates. However, the edge flow channel of the large-sized carbon felt 104 is easily affected by the fixture plate structure, resulting in uneven local flow rate and the formation of a flow stagnation zone. Compared with the small size (4cm×4cm) and low flow rate (90mL / min) of Example 1, Figure 11 As shown, the overall flow uniformity of the electrolyte is improved under this working condition, but there is still an electrolyte-poor area of about 12% in the edge area, which verifies the significant influence of the size and flow velocity of the carbon felt 104 on the flow distribution.

[0109] Example 3

[0110] The difference between Example 3 and Example 1 is that the area of the detection carbon felt 104 is 10 cm×10 cm, the electrolyte flow rate is 252 mL / min, the low-temperature electrolyte temperature is constant at 20° C., and the high-temperature electrolyte temperature is constant at 35° C.

[0111] The difference after the change: Figure 13 As shown, when the area of carbon felt 104 is 10cm×10cm and the flow rate is 252mL / min, the temperature and time curves show obvious fluctuations, especially in the middle area of the detection cavity (such as P3 and P5). The infrared thermal image shows that the heating rate near the inlet (P1, P2) is faster (0.4℃ / s), while the heating rate of P6 and P8 areas far away from the inlet is less than 0.1℃ / s, forming an obvious temperature field unevenness. This is because the diffusion of electrolyte in the micropores of carbon felt 104 is dominant at low flow rates, the flow channel resistance causes the renewal of electrolyte in the distal area to be slow, and the local turbulence effect aggravates the temperature fluctuation. Compared with the high flow rate working condition of Example 2, the area of the electrolyte-poor area under this condition accounts for 18%, and the low fluidity area accounts for more than 20%, which verifies the adverse effect of low flow rate on the uniform distribution of electrolyte and provides a data basis for flow channel optimization.

[0112] Table 1 is a comparative analysis table of flow battery electrolyte distribution test conditions.

[0113] Table 1

[0114]

[0115]

[0116] As shown in Table 1, the three examples reveal the distribution patterns of electrolyte on the surface of the carbon felt 104 in flow batteries by controlling the area of the carbon felt 104 and the electrolyte flow rate. For a small carbon felt 104 (4 cm × 4 cm) with a low flow rate (90 mL / min), diffusion dominates electrolyte migration, resulting in a relatively uniform temperature field. When the carbon felt 104 area is increased to 10 cm × 10 cm and the flow rate is increased to 846 mL / min, turbulence becomes the dominant factor in migration, improving overall fluidity but still maintaining stagnation zones at the edges. When the carbon felt 104 area is 10 cm × 10 cm and the flow rate is 252 mL / min, diffusion and flow resistance combine to lead to uneven electrolyte distribution, significantly increasing the proportion of lean and low-fluidity areas. This comparative analysis provides an experimental basis for optimizing the size and electrolyte flow rate of the carbon felt 104 in flow batteries, demonstrating that high flow rates and a rational flow channel structure can effectively improve electrolyte distribution uniformity.

[0117] 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 scope of protection of the present invention.

Claims

1. A test device for measuring the distribution of electrolyte in a flow battery on a carbon felt surface, comprising a detection chamber (1), a circulation pump (2), a cooling water bath (3), a heating water bath (4), and an infrared thermal imager (7), wherein a first liquid storage tank (5) is installed inside the cooling water bath (3), and a second liquid storage tank (6) is installed on the top of the heating water bath (4), and characterized in that: The output end of the detection chamber (1) is connected to the input end pipeline of the circulation pump (2), the output end pipeline of the circulation pump (2) is connected to a control valve (9), the two input ends of the control valve (9) are connected to the input end pipelines of the liquid storage tank 1 (5) and the liquid storage tank 2 (6), the output end pipeline of the liquid storage tank 2 (6) is connected to a defoaming mechanism (10), the pipeline at the output end of the liquid storage tank 1 (5) and the pipeline at the output end of the defoaming mechanism (10) are connected to the input pipeline of the detection chamber (1), and the pipeline at the output end of the liquid storage tank 1 (5) and the pipeline at the output end of the defoaming mechanism (10) are both installed with an anti-backflow mechanism (11); The detection chamber (1) comprises a base plate (101), a shell (102), a clamping plate (103), a carbon felt (104), a polyethylene sheet (105) and an infrared temperature measuring hole (113); the front end of the base plate (101) is bolted with the shell (102); two stacked clamping plates (103) are installed between the base plate (101) and the shell (102); a carbon felt (104) and a temperature sensor are installed between the two clamping plates (103); a polyethylene sheet (105) is embedded in the front end of the clamping plate (103); and nine infrared temperature measuring holes (113) distributed in a rectangular shape are opened on the outer wall of the shell (102); The infrared thermal imager (7) is located at the front end of the housing (102); A flow controller (8) is installed on the pipeline between the output end of the circulation pump (2) and the input end of the control valve (9).

2. The testing device for the distribution of electrolyte in a flow battery on a carbon felt surface according to claim 1, characterized in that: The detection chamber (1) further comprises an outflow groove (106), a mounting groove (107) and an inflow groove (108); the two opposite surfaces of the two clamping plates (103) are provided with an outflow groove (106), a mounting groove (107) and an inflow groove (108); the outflow groove (106) is located above the mounting groove (107) and is communicated with the mounting groove (107); the inflow groove (108) is located below the mounting groove (107) and is communicated with the mounting groove (107); and the carbon felt (104) is located between the two mounting grooves (107).

3. The testing device for the distribution of electrolyte in a flow battery on a carbon felt surface according to claim 1, characterized in that: A liquid outlet pipe (109) and a liquid inlet pipe (110) are fixedly connected to the side wall of the housing (102); the liquid outlet pipe (109) corresponds to the port position of the output end of the outflow trough (106); the liquid inlet pipe (110) corresponds to the port position of the input end of the inflow trough (108); the output end of the liquid outlet pipe (109) is connected to the input end pipeline of the circulation pump (2); the input end of the liquid inlet pipe (110) is connected to the output end of the liquid storage tank (5) and the output end pipeline of the defoaming mechanism (10).

4. The testing device for the distribution of electrolyte in a flow battery on a carbon felt surface according to claim 1, characterized in that: A sealing ring (112) is fixedly installed between the base plate (101) and the housing (102), and a bolt connecting the base plate (101) and the housing (102) passes through the sealing ring (112).

5. The testing device for the distribution of electrolyte of a flow battery on a carbon felt surface according to claim 1, characterized in that: The control valve (9) comprises a housing (901), a ball valve (902), a flow groove (903) and a turning handle (904). The housing (901) is fixedly connected between the output pipe of the circulation pump (2) and the input pipes of the liquid storage tank (5) and the liquid storage tank (6). The housing (901) is provided with a ball valve (902) which is movably installed inside. The interior of the ball valve (902) is fixedly connected with the flow groove (903). The top of the ball valve (902) is fixedly connected with the turning handle (904). The rotational resistance between the turning handle (904) and the housing (901) is greater than the flow thrust of the liquid passing through the flow groove (903).

6. The testing device for the distribution of electrolyte of a flow battery on a carbon felt surface according to claim 1, characterized in that: The defoaming mechanism (10) comprises a tank body (1001), a tapered groove (1002) and a thin flow channel (1003); the tank body (1001) is located at the front end of the second liquid storage tank (6); the liquid inlet pipe of the tank body (1001) is fixedly connected between the output end of the second liquid storage tank (6) and the top of the outer wall of the tank body (1001); the liquid outlet pipe of the tank body (1001) is fixedly connected to the far end of the tank body (1001); The bottom of the outer wall on the side away from the liquid inlet pipe is communicated with the inner cavity of the tank body (1001) and is connected to the input end of the liquid inlet pipe (110). The inner wall of the liquid inlet pipe of the tank body (1001) is provided with a tapered groove (1002) and a thin flow channel (1003). The inner diameter of the liquid inlet pipe of the tank body (1001) is five times the inner diameter of the thin flow channel (1003). The thin flow channel (1003) is communicated with the inner cavity of the tank body (1001).

7. The testing device for the distribution of electrolyte of a flow battery on a carbon felt surface according to claim 1, characterized in that: The defoaming mechanism (10) further comprises a mounting cylinder (1004), a hydrophobic membrane (1005), an activated carbon filter block (1006), a sealing cover (1007) and an exhaust pipe (1008); the mounting cylinder (1004) is fixedly connected to the top of the tank body (1001); the hydrophobic membrane (1005) is fixedly installed between the mounting cylinder (1004) and the tank body (1001); the activated carbon filter block (1006) is fixedly installed inside the mounting cylinder (1004); the sealing cover (1007) is threadedly installed on the top of the mounting cylinder (1004); and the exhaust pipe (1008) is fixedly connected to the top of the sealing cover (1007).

8. The testing device for the distribution of electrolyte of a flow battery on a carbon felt surface according to claim 1, characterized in that: The anti-backflow mechanism (11) comprises a second shell (1101), a spring (1102) and a baffle (1103); the second shell (1101) is installed in the pipeline at the output end of the first liquid storage tank (5) and the pipeline at the output end of the defoaming mechanism (10); the spring (1102) is fixedly installed inside the second shell (1101); the baffle (1103) is slidably installed inside the second shell (1101); the end of the spring (1102) is fixedly connected to the outer wall of the thin flow channel (1003).

9. A method for testing the distribution of electrolyte in a flow battery on a carbon felt surface, characterized in that: The test device for the distribution of the flow battery electrolyte on the carbon felt surface according to any one of claims 1 to 8 specifically comprises the following steps: S1. Equipment Assembly and Preparation S1-1. The carbon felt (104) is installed in the detection chamber (1); S1-2. Electrolyte is added to each of the liquid storage tanks 1 (5) and 2 (6); S1-3. The liquid storage tank (5) is placed in a refrigerated water bath (3), and the liquid storage tank (6) is placed in a hot water bath (4); S1-4. Turn on the cooling water bath (3) and the hot water bath (4) to keep the electrolyte temperature in the storage tank (5) constant at 20°C ± 2°C and the electrolyte temperature in the storage tank (6) constant at 35°C ± 2°C. S1-5 adjust the infrared thermal imager (7) so that it is facing the infrared temperature measuring hole (113) of the detection chamber (1) and connected to the computer; S2. System wetting and exhaust S2-1 operating control valve (9) connected to the circulation pump (2) and the liquid storage tank (5); S2-2. Start the circulation pump (2) and the flow controller (8), control the low-temperature electrolyte to flow through the detection chamber (1) at a first flow rate, the first flow rate is 50 to 300 mL / min, and continue to circulate until the carbon felt (104) is fully wetted and the gas in the system is exhausted; S2-3. The temperature of the carbon felt (104) is monitored by a temperature sensor between the two splints (103) until the temperature stabilizes at 20°C ± 0.5°C; S3. Hot electrolyte injection and data acquisition S3-1 operation control valve (9) switching connected to the circulation pump (2) and the liquid storage tank two (6); S3-2. After the high-temperature electrolyte is discharged from the second storage tank (6), the bubbles in the high-temperature electrolyte are removed by a defoaming mechanism (10), and the electrolyte is ensured to flow in one direction by an anti-backflow mechanism (11); S3-3. The high-temperature electrolyte is controlled by a flow controller (8) to flow through the detection chamber (1) at a flow rate of 90 mL / min; S3-4. Record the switching time as the initial time, and perform the following operations synchronously from the initial time: a. Using an infrared thermal imager (7) to continuously collect infrared thermal images of the surface of the carbon felt (104) within the detection cavity (1); b. using a temperature sensor to continuously record the temperature change data of one or more selected test points on the carbon felt (104) over time; S4. Data Analysis S4-1. Based on the infrared thermal image collected in step S3, the distribution area of the electrolyte on the surface of the carbon felt (104) is determined by calculating the spatial gradient of the temperature field, wherein the area with a temperature gradient greater than 2°C / cm is determined to be an electrolyte-rich area, and the area with a temperature gradient less than 0.5°C / cm is determined to be an electrolyte-poor area; S4-2. Based on the temperature-time data recorded in step S3, a linear fit is performed on the temperature curve of each test point. The fitting slope is used as the heating rate. The test points with a heating rate greater than 0.3°C / s are determined to be in the high fluidity region, and the test points with a heating rate less than 0.1°C / s are determined to be in the low fluidity region. S4-3. Evaluate the uniformity of electrolyte flow based on the distribution ratio of electrolyte-rich and electrolyte-poor areas and the proportion of high-mobility and low-mobility areas. If the area ratio of electrolyte-poor areas is less than 10% and the proportion of low-mobility areas is less than 15%, it is judged to be uniformly distributed.

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