An electrochemical cell for in-situ testing of slurry batteries with adjustable flow channels

Abstract

The present invention belongs to the field of electrochemical technology and discloses an electrochemical cell for in-situ testing of slurry batteries with adjustable flow channels. The cell is suitable for in-situ Raman and X-ray diffraction characterization of slurry batteries and includes a rotating base, an upper sealing ring, a window adjustment plate, a flow channel plate, a battery separator, a negative electrode, a negative electrode current collector, a lower sealing ring, a base, an inlet / outlet plate, an inlet / outlet sealing ring, and an inlet / outlet pipe. The present invention can conveniently change the shape of the slurry flow channel and adjust the width of the slurry flow channel in situ; a multi-directional observation window is provided on the top of the electrochemical cell, and the window type is adjusted by rotation to adapt to different characterization instruments. The slurry in different areas is selected for observation by adjusting the window position. Raman laser or X-rays are directly irradiated onto the slurry electrode through the window to achieve in-situ signal acquisition. The present invention has profound significance for clarifying the charge and discharge mechanism of slurry batteries and realizing their potential for large-scale energy storage applications.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemistry, and in particular relates to an electrochemical cell for in-situ testing of a slurry battery. Background Art

[0002] Slurry batteries are an emerging electrochemical energy storage technology in which all or part of the electrodes are in a slurry state. Slurry electrodes are composed of active material particles, a conductive agent, and an electrolyte. They convert electrical energy into chemical energy through redox reactions, achieving the storage and release of electrical energy. The electrode slurry preparation process for slurry batteries is simple, eliminating the need for the complex preparation processes of traditional lithium-ion battery electrodes, such as coating and drying. Moreover, the semi-solid electrode slurry is easy to recycle, reducing production and reuse costs. In addition, compared with traditional flow batteries, slurry batteries not only achieve the decoupling of battery capacity and power, but also have an active material content that is not limited by its own solubility in the electrolyte, resulting in a significant increase in battery energy density. Therefore, slurry batteries have application prospects in large-scale energy storage. In the process of slurry battery research, advances in characterization technology are crucial to the optimization of slurry battery performance and the development of new system slurry batteries.

[0003] Raman spectroscopy and X-ray diffraction techniques are commonly used characterization methods in materials chemistry research. They have the advantages of fast analysis speed, high repeatability, and the ability to perform non-destructive qualitative and quantitative analysis of materials. Raman spectroscopy can directly obtain the structure, composition, and chemical bond state of slurry electrodes by detecting molecular vibrations. X-ray diffraction analysis uses the diffraction effect of X-rays in crystalline materials to analyze the structure of materials. By measuring the diffraction angle position and the integrated intensity of the spectral lines, qualitative and quantitative analysis of compounds can be performed. It has important scientific significance and application value for clarifying the deionization / intercalation process of active substances and then inferring the electrochemical reaction mechanism of slurry batteries.

[0004] Currently, the two test technologies mentioned above have two types of characterization: in-situ and ex-situ. Since the active material of the slurry battery exists in a flowing semi-solid slurry, the ex-situ characterization is prone to cause problems such as electrolyte solvent volatilization, system contamination, and damage to the active material structure during the sample preparation process, affecting the accuracy of the test results. In addition, due to the differences in the charge and discharge states of different batteries, there are certain errors in the ex-situ characterization results. In contrast, in-situ characterization can synchronously collect the test signals of the material during the battery charge and discharge process, thereby obtaining real-time information on the material structure and composition changes, and the spectrum is more accurate. At present, the more common in-situ battery testing devices are button-type and flange-type, but they do not have internal slurry flow channels and circulation devices, and cannot meet the operation requirements of slurry batteries. Therefore, it is imperative to design an in-situ testing device that matches the slurry battery system. Summary of the Invention

[0005] The purpose of the present invention is to address the shortcomings of existing characterization technologies and provide an electrochemical cell for in-situ testing of slurry batteries with adjustable flow channels, so as to meet the needs of synchronously collecting Raman or X-ray diffraction signals of active substances with different reaction degrees in the electrode slurry during the charge and discharge process of the slurry battery, and obtain more accurate information on the structure and composition changes of the electrode materials.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides an electrochemical cell for in-situ testing of a slurry battery with adjustable flow channels, comprising a base, on which a negative electrode current collector, a negative electrode, a battery separator, and a flow channel plate are sequentially arranged; a lower sealing ring is arranged between the flow channel plate and the base, and the negative electrode current collector, the negative electrode, and the battery separator are all located within the lower sealing ring;

[0008] A window adjustment plate, a rotating base, and an upper sealing ring are provided on the flow channel plate; the window adjustment plate can be inserted into the rotating base and rotate relative to the rotating base; an upper sealing ring is provided in the annular space enclosed by the window adjustment plate, the rotating base, and the flow channel plate; the window adjustment plate is provided with a Raman window, a first XRD window, and a second XRD window; an adjustment column is further provided on the upper surface of the window adjustment plate for driving the window adjustment plate to rotate relative to the rotating base;

[0009] The flow channel plate is composed of a first plate and a second plate, wherein the first plate and the second plate are spaced apart and the edges of the opposing surfaces thereof correspond in shape, so that a slurry flow channel of a certain shape is formed between the first plate and the second plate, and the slurry flow channel is used for the circulation of the positive electrode slurry;

[0010] Threaded racks are respectively distributed on the side of the first plate and the side of the second plate, and the threaded racks are threadedly connected to the adjustment knob; by turning the adjustment knob, the first plate and the second plate can be controlled to move toward or away from each other, thereby changing the distance between the first plate and the second plate, thereby adjusting the width of the slurry flow channel;

[0011] The rotating base, the upper sealing ring, the lower sealing ring and the base are fixedly connected, and inlet / outlet plates are respectively provided on both sides of the flow channel plate, the upper part of the inlet / outlet plate is fixed to the rotating base, and the lower part is fixed to the base; the inlet / outlet sealing ring is padded between the inlet / outlet plate and the upper sealing ring, the flow channel plate and the lower sealing ring; the inlet / outlet plate and the inlet / outlet sealing ring are sealed with inlet / outlet pipes; the two inlet / outlet pipes are respectively connected to the two ends of the slurry flow channel, one serving as an inlet pipe and the other as an outlet pipe, so as to realize the inflow and outflow of positive electrode slurry.

[0012] Furthermore, the window adjustment plate is a circular plate structure, the diameter of its upper half is larger than the diameter of its lower half; the rotating base is a plate structure with a circular inner hole, the thickness of which is the same as the thickness of the upper half of the window adjustment plate; the inner diameter of the rotating base matches the diameter of the upper half of the window adjustment plate, so as to enable the window adjustment plate to be inserted into the rotating base.

[0013] Furthermore, the contact portions between the upper sealing ring and the window adjustment plate and the flow channel plate are coated with vacuum grease.

[0014] Furthermore, the material of the Raman window is one of quartz, borosilicate glass, sapphire, and polymethyl methacrylate; the material of the first XRD window is metallic beryllium, and the material of the second XRD window is polyimide.

[0015] Furthermore, the Raman window, the first XRD window and the second XRD window are evenly distributed on the window adjustment plate.

[0016] Furthermore, the Raman window, the first XRD window and the second XRD window are uniformly distributed in the circumferential direction at equal angles.

[0017] Furthermore, the shape of the slurry flow channel is one of a straight line, a meander, an S-shaped structure, an interdigitated shape, and a bionic structure.

[0018] Furthermore, mounting brackets are respectively connected to both sides of the base, and the mounting brackets are fixedly connected to the adjusting knob at the height of the flow channel plate.

[0019] Furthermore, the fixed connection among the rotating base, the upper sealing ring, the lower sealing ring and the base is one of bolt connection, rivet connection, punch riveting, hook connection and bite seam connection.

[0020] Furthermore, the rotating base, the upper sealing ring, the lower sealing ring and the base are respectively provided with circular through holes at the four corners, and the four fixing bolts are inserted into the circular through holes and fixed with nuts; and the flow channel plate is respectively provided with long holes at the four corners, and the length direction of the long holes extends along the moving direction of the first plate body and the second plate body, and the width of the long holes matches the diameter of the fixing bolts.

[0021] Furthermore, the adjustment column, the window adjustment plate, the rotating base, the base, and the mounting frame are made of one of polytetrafluoroethylene, polymethyl methacrylate, polyethylene terephthalate, polycarbonate, and polyformaldehyde resin; the negative electrode current collector is made of one of aluminum, copper, titanium, nickel, and stainless steel; and the upper sealing ring and the lower sealing ring are made of one of silicone, nitrile rubber, isoprene rubber, and ethylene propylene rubber.

[0022] The beneficial effects of the present invention are:

[0023] (1) The present invention can change the shape of the slurry flow channel by replacing the flow channel plate, thereby exploring the real-time information of the changes in the material structure and composition of the electrode slurry during the battery charging and discharging process in the flow channels of different shapes; it can also adjust the width of the slurry flow channel in situ, change the electrode flow rate and the inlet and outlet pressure drop, affect the local flow distribution and ion transport dynamics of the slurry in the flow channel, and change the electrode reaction efficiency of the slurry battery to realize the collection of real-time information on the changes in the slurry electrode material structure and composition under different reaction conditions as the battery charges and discharges; therefore, it can meet the requirements of in-situ testing of slurry batteries under various working conditions.

[0024] (2) The present invention can adjust the observation window type in situ without disassembling the device, and select a matching observation window according to different characterization methods, avoiding multiple assembly of different electrochemical cells when performing different characterization tests, thereby improving test accuracy and repeatability.

[0025] (3) The present invention can adjust the observation window position in multiple directions, so as to realize in-situ Raman and XRD characterization of the electrode slurry at different positions in the flow channel, thereby exploring the reaction degree of active substances at different positions in the flow channel and studying the electrochemical reaction efficiency of flow channels with different structures.

[0026] (4) The present invention uses sealing rings and mechanical connections simultaneously during the assembly process, which can achieve long-term effective sealing, adapt to the long charging and discharging time of slurry batteries, and improve the accuracy of in-situ Raman and XRD test results.

[0027] (5) The device of the present invention has a simple structure and is easy to disassemble and assemble. It can be operated in various working conditions such as a glove box and is suitable for in-situ Raman and XRD testing of various types of slurry batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A front view of an electrochemical cell for in-situ testing of a slurry battery provided by the present invention.

[0030] Figure 2 This is a left view of the electrochemical cell for in-situ testing of a slurry battery provided by the present invention.

[0031] Figure 3 A top view of the electrochemical cell for in-situ testing of a slurry battery provided by the present invention.

[0032] Figure 4 This is a top view of the flow channel plate in the slurry battery in-situ test electrochemical cell provided by the present invention.

[0033] Figure 5 This is the constant current charge and discharge curve of the semi-solid lithium slurry battery in Experimental Example 1 when the flow channel spacing is adjusted to 2.5 mm and the in-situ Raman spectrum on the slurry inlet side.

[0034] Figure 6 This is the constant current charge-discharge curve and in-situ Raman spectrum of the slurry outlet side of the semi-solid lithium slurry battery in Experimental Example 1 when the flow channel spacing is adjusted to 5.0 mm.

[0035] Figure 7 This is the constant current charge-discharge curve and in-situ XRD spectrum of the slurry inlet side of the semi-solid lithium slurry battery in Experimental Example 2 when the flow channel spacing is adjusted to 2.5 mm.

[0036] In the above figure: 1: adjustment column, 2: window adjustment plate, 3: Raman window, 4: rotating base, 5: upper sealing ring, 6: inlet / outlet screw, 7: inlet / outlet plate, 8: inlet / outlet sealing ring, 9: inlet / outlet pipe, 10: flow channel plate, 11: positive electrode slurry, 12: negative electrode current collector, 13: base, 14: negative electrode, 15: diaphragm, 16: lower sealing ring, 17: mounting bracket, 18: adjustment knob, 19: fixing bolt, 20: first XRD window, 21: second XRD window, 22: long hole. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0038] like Figures 1 to 3As shown, the present invention relates to an electrochemical cell for in-situ testing of a slurry battery with adjustable flow channel, which can be suitable for in-situ Raman and X-ray diffraction characterization of a slurry battery, including a rotating base 4, an upper sealing ring 5, a window adjustment plate 2, a flow channel plate 10, a battery separator 15, a negative electrode 14, a negative electrode current collector 12, a lower sealing ring 16, a base 13, an inlet / outlet plate 7, an inlet / outlet sealing ring 8, and an inlet / outlet pipe 9.

[0039] The window adjustment plate 2, rotating base 4, and upper sealing ring 5 are all located on the flow channel plate 10. The window adjustment plate 2 is a circular plate with a larger diameter at the top than at the bottom, and the two halves form a right-angled step transition. The rotating base 4 is a plate with a square outer surface and a circular inner surface, and its thickness is the same as that of the upper half of the window adjustment plate 2. The inner diameter of the rotating base 4 matches the diameter of the upper half of the window adjustment plate 2, allowing the upper half of the window adjustment plate 2 to fit snugly within the rotating base 4 and allowing the window adjustment plate 2 to rotate relative to the rotating base 4. After the window adjustment plate 2 is inserted into the rotating base 4, the upper sealing ring 5 is placed in the annular space formed by the window adjustment plate 2, rotating base 4, and flow channel plate 10 to seal the adjustable observation mechanism from the flow channel plate 10. Furthermore, a suitable amount of vacuum grease is applied to the contact areas between the upper sealing ring 5, the window adjustment plate 2, and the flow channel plate 10 to ensure rotation of the window adjustment plate 2 and adjustment of the flow channel plate 10.

[0040] The window adjustment plate 2 is provided with three observation windows, namely the Raman window 3, the first XRD window 20 and the second XRD window 21. The materials of the Raman window 3, the first XRD window 20 and the second XRD window 21 have high signal transmittance and high mechanical strength, and can withstand the high liquid pressure during the operation of the slurry battery. When performing in-situ Raman testing, the Raman window 3 can be made of quartz, borosilicate glass, sapphire, polymethyl methacrylate and other materials according to the different absorption of light in a specific wavelength band by the window material under different incident waves. When performing in-situ XRD testing, in order to avoid the window affecting the penetration of X-rays and the interference of the X-ray diffraction signal of the window material itself, the first XRD window 20 uses metal beryllium and the second XRD window 21 uses polyimide.

[0041] As a preferred embodiment, the Raman window 3, the first XRD window 20, and the second XRD window 21 are evenly distributed on the window adjustment plate 2. In this embodiment, the Raman window 3, the first XRD window 20, and the second XRD window 21 are all rectangular, with their length directions arranged along the radial direction of the window adjustment plate 2, and the three are evenly distributed circumferentially at equal angles, that is, the angle between two adjacent observation windows is 120°.

[0042] The upper surface of the window adjustment plate 2 is also provided with an adjustment column 1, typically located near the edge of the plate. This column 1 is used to propel the plate 2 in rotation relative to the rotating base 4 and upper sealing ring 5. During in-situ testing, depending on the test method, the adjustment column 1 is held and the window adjustment plate 2 is rotated to select the appropriate observation window for different characterization instruments. Furthermore, depending on the desired test location, the adjustment column 1 is held and the window adjustment plate 2 is rotated to select the appropriate test location, allowing observation of different areas of the slurry. Raman laser light or X-rays are then irradiated directly onto the slurry electrodes through the corresponding observation windows, enabling in-situ signal acquisition.

[0043] like Figure 4 As shown, the flow channel plate 10 is composed of a first plate body 10-1 and a second plate body 10-2. The first plate body 10-1 and the second plate body 10-2 are spaced apart, and the edges of the opposing surfaces thereof correspond in shape, so that a slurry flow channel of a certain shape is formed between the first plate body 10-1 and the second plate body 10-2. The slurry flow channel extends from one side of the flow channel plate 10 to the other side and is used for the circulation of the positive electrode slurry 11. The shape of the slurry flow channel can be a straight line, a meander, an S-shape, an interdigital shape, a biomimetic structure, etc., and its shape can be changed according to test requirements.

[0044] Threaded racks are distributed on the side (one side or both sides) of the first plate 10-1 and the side (one side or both sides) of the second plate 10-2. The two rows of threaded racks are respectively engaged with the adjusting knob 18 which is also provided with threads. By turning the adjusting knob 18, the first plate 10-1 and the second plate 10-2 can be controlled to move toward or away from each other, thereby changing the distance between the first plate 10-1 and the second plate 10-2, and realizing the width adjustment of the slurry flow channel. Long holes 22 are respectively provided at the four corners of the flow channel plate 10, that is, two long holes 22 are respectively provided on the first plate 10-1 and the second plate 10-2, and the length direction of the long holes 22 extends along the movement direction of the first plate 10-1 and the second plate 10-2. The width of the long holes 22 matches the diameter of the fixing bolts 19, so that the first plate 10-1 and the second plate 10-2 will not be restricted by the fixing bolts 19 during movement.

[0045] It can be seen that by replacing the flow channel plate 10, the shape of the slurry flow channel can be changed, and real-time information on the changes in the material structure and composition of the electrode slurry during the battery charging and discharging process under different flow channel environments can be collected; by adjusting the knob 18, the width of the slurry flow channel can be adjusted in situ, the electrode flow rate and the inlet and outlet pressure drop can be changed, and the local flow distribution and ion transport dynamics of the slurry in the flow channel can be affected, thereby changing the electrode reaction efficiency of the slurry battery and realizing the collection of real-time information on the changes in the slurry electrode material structure and composition during the battery charging and discharging process under different reaction conditions. In short, by replacing the flow channel plate and adjusting the width of the slurry flow channel in situ, the present invention can meet the requirements for in-situ battery testing of slurry batteries under various operating conditions.

[0046] Generally, the total length of the slurry flow channel can be adjusted according to test requirements and is generally within the range of 1-50 cm. The thickness of the flow channel plate 10 is generally selected within the range of 1-5 mm. The material of the flow channel plate 10 is generally selected to have excellent conductivity and no side reaction with the electrolyte, and can be a metal material such as aluminum, copper, titanium, nickel, stainless steel, etc.

[0047] Beneath the flow channel plate 10 are located the battery separator 15, the negative electrode 14, the negative electrode current collector 12, a lower sealing ring 16, and a base 13. The base 13 is located at the very bottom of the electrochemical cell. The lower sealing ring 16 is located between the base 13 and the flow channel plate 10. Inside the lower sealing ring 16, the battery separator 15, the negative electrode 14, and the negative electrode current collector 12 are located, in order from top to bottom. Mounting brackets 17 are located on either side of the base 13. The bottom of the mounting brackets 17 is fixedly connected to the base 13, and the top extends to the height of the flow channel plate 10 and is fixedly connected to the adjustment knob 18.

[0048] Circular through-holes are provided at the four corners of the rotating base 4, upper sealing ring 5, lower sealing ring 16, and base 13. These circular through-holes have the same diameter and are compatible with fixing bolts 19. The electrochemical cell is assembled by inserting four fixing bolts 19 from top to bottom into the circular through-holes at the four corners of the rotating base 4, upper sealing ring 5, lower sealing ring 16, and base 13, and then securing them with nuts. In addition to the aforementioned sealing ring + bolt connection, the present invention can also adopt sealing ring + rivet connection, sealing ring + hole riveting, sealing ring + hook connection, sealing ring + bite seam connection, and other connection methods, all of which can prevent leakage of high-pressure fluid electrodes from the openings.

[0049] Inlet / outlet plates 7 are provided on either side of the flow channel plate 10. The upper portion of the inlet / outlet plate 7 is fixed to the rotating base 4, and the lower portion is fixed to the base 13. An inlet / outlet sealing ring 8 is placed between the inlet / outlet plate 7, the upper sealing ring 5, the flow channel plate 10, and the lower sealing ring 16. Inlet / outlet pipes 9 are sealed between the inlet / outlet plate 7 and the inlet / outlet sealing ring 8. The two inlet / outlet pipes 9 are connected to the two ends of the slurry flow channel of the flow channel plate 10, one serving as the inlet pipe and the other as the outlet pipe, allowing the positive electrode slurry 11 to flow in and out.

[0050] The materials of the adjustment column 1, window adjustment plate 2, rotating base 4, base 13, and mounting bracket 17 should be non-reactive with the electrolyte, including but not limited to a polymer insulating material selected from polytetrafluoroethylene, polymethyl methacrylate, polyethylene terephthalate, polycarbonate, and polyoxymethylene resin. The negative electrode current collector 12 should have excellent conductivity, including but not limited to a metal material selected from aluminum, copper, titanium, nickel, and stainless steel. The upper sealing ring 5 and lower sealing ring 16 should have good elastic deformation and be non-reactive with the electrolyte, including but not limited to a polymer insulating material selected from silicone, nitrile rubber, isoprene rubber, and ethylene propylene rubber. Their thickness should be adjusted according to the required volume of the fluid electrode cavity.

[0051] Taking the semi-solid lithium slurry battery as an experimental example, the structural changes of the polyaniline positive electrode slurry during the charge and discharge process are characterized by in-situ Raman spectroscopy, and the structural changes of the lithium iron phosphate positive electrode slurry during the charge and discharge process are characterized by in-situ X-ray diffraction.

[0052] Experimental Example 1:

[0053] Electrochemical performance testing based on an in-situ electrochemical cell with adjustable flow channels:

[0054] Figure 5 The semi-solid lithium slurry battery with polyaniline as the positive electrode is at 0.2mA / cm 2 The constant current charge-discharge curve and in-situ Raman spectrum when the slurry flow channel spacing is adjusted to 2.5mm under the current density. Figure 5 The test results show that the specific capacity of the semi-solid lithium slurry battery is 72.9 mAh / g, indicating that the semi-solid lithium slurry battery assembled by the device operates normally. The structural changes of the polyaniline inside the inlet slurry during the charge and discharge process were characterized using a laser confocal Raman spectrometer, where the laser wavelength was 532 nm, the laser power was 12.5 mW, and the single spectrum acquisition time was 4 s. The Raman spectrum is shown in the figure below. Figure 5 Curve 1 is the initial state, curve 3 is the state after the first cycle is fully charged, curve 5 is the state after the first cycle is fully discharged, and curves 2 and 4 are the intermediate states of the charging and discharging processes respectively. When fully charged, 1600cm -1The characteristic peaks of the benzene form of polyaniline were significantly weakened, indicating that polyaniline was converted from the benzene form to the quinone form and oxidized. Subsequently, when the battery was fully discharged, the characteristic peaks of the benzene form of polyaniline were significantly strengthened, indicating that polyaniline was converted from the benzene form to the quinone form and reduced. The in situ Raman characterization results clearly demonstrated the structural changes of polyaniline during the charge and discharge process, demonstrating the effectiveness of the in situ Raman testing electrochemical cell.

[0055] Then, the channel spacing was adjusted to 5.0 mm and the current was adjusted to 0.2 mA / cm 2 The above semi-solid lithium slurry battery was subjected to constant current charge and discharge tests and in-situ Raman spectroscopy characterization under current density. The results are as follows Figure 6 As shown. The specific capacity of the semi-solid lithium slurry battery is 65.4mAh / g, indicating that the semi-solid lithium slurry battery assembled by the device operates normally. The structural changes of the polyaniline inside the outlet slurry during the charge and discharge process were characterized using a laser confocal Raman spectrometer, where the laser wavelength is 532nm, the laser power is 12.5mW, and the single spectrum acquisition time is 4s. The Raman spectrum is shown as follows Figure 6 Curve 1 is the initial state, curve 3 is the state after the first cycle is fully charged, curve 5 is the state after the first cycle is fully discharged, and curves 2 and 4 are the intermediate states of the charging and discharging processes respectively. When fully charged, 1600cm -1 The characteristic peak of the benzene form of polyaniline is significantly weakened, indicating that polyaniline is converted from the benzene form to the quinone form and is oxidized. Then the battery is fully discharged, and the characteristic peak of the benzene form of polyaniline is significantly enhanced, indicating that polyaniline is converted from the benzene form to the quinone form and is reduced.

[0056] Example 2:

[0057] The channel spacing was adjusted to 2.5 mm, and constant current charge and discharge tests and in-situ X-ray diffraction characterization were performed on the semi-solid lithium slurry battery with lithium iron phosphate as the positive electrode. The results are as follows Figure 7 The specific capacity of the semi-solid lithium slurry battery is 304.4 mAh / g, indicating that the semi-solid lithium slurry battery assembled by the device operates normally. The structural changes of lithium iron phosphate inside the slurry during the charge and discharge process were characterized using an X-ray diffractometer. The XRD spectrum is shown in Figure 7 As shown. Curve 1 represents the initial state, Curve 3 represents the state after the first full charge, Curve 5 represents the state after the first full discharge, and Curves 2 and 4 represent the intermediate states during the charge and discharge processes, respectively. When fully charged, the diffraction peaks of the lithium iron phosphate at positions 25.7°, 29.8°, and 35.7° shift to 26.2°, 31.2°, and 37.1°. This indicates that the interlayer spacing of the lithium iron phosphate decreases, lithium ions are released, and the lithium iron phosphate gradually transforms into FePO4. Subsequently, when the battery is fully discharged, these diffraction peaks return to their initial positions, indicating that lithium ions are reinserted into FePO4 to form lithium iron phosphate.

[0058] According to the above embodiments and experimental examples, it can be seen that the present invention provides an electrochemical cell for in-situ testing of slurry batteries with adjustable flow channels, which can not only meet the operating requirements of slurry batteries, but also synchronously collect Raman or X-ray diffraction signals of active substances with different reaction degrees in the electrode slurry during the battery charging and discharging process. The present invention realizes the replacement of the slurry flow channel shape and the in-situ adjustment of the slurry flow channel width, and can study the influence of different flow channel structures on the reaction state of active substances in slurry batteries during the battery cycle. In addition, the present invention can perform in-situ characterization of slurries at different positions in the flow channel, explore the reaction degree of active substances at different positions in the flow channel, and study the electrochemical reaction efficiency of flow channels with different structures. The present invention also has the advantages of simple structure, easy assembly, accurate test results, and a wide range of applications. It is of profound significance for clarifying the charging and discharging mechanism of slurry batteries and exerting their potential for large-scale energy storage applications.

[0059] The foregoing description is merely an embodiment of the present invention and is not intended to limit the scope of protection of this application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application shall be included within the scope of protection of this application.

Claims

1. A slurry battery in-situ test electrochemical cell with adjustable flow channel, comprising a base, characterized in that: A negative electrode current collector, a negative electrode, a battery separator and a flow channel plate are sequentially arranged on the base; a lower sealing ring is arranged between the flow channel plate and the base, and the negative electrode current collector, the negative electrode and the battery separator are all located within the lower sealing ring; A window adjustment plate, a rotating base, and an upper sealing ring are provided on the flow channel plate; the window adjustment plate can be inserted into the rotating base and rotate relative to the rotating base; an upper sealing ring is provided in the annular space enclosed by the window adjustment plate, the rotating base, and the flow channel plate; the window adjustment plate is provided with a Raman window, a first XRD window, and a second XRD window; an adjustment column is further provided on the upper surface of the window adjustment plate for driving the window adjustment plate to rotate relative to the rotating base; The flow channel plate is composed of a first plate and a second plate, wherein the first plate and the second plate are spaced apart and the edges of the opposing surfaces thereof correspond in shape, so that a slurry flow channel of a certain shape is formed between the first plate and the second plate, and the slurry flow channel is used for the circulation of the positive electrode slurry; Threaded racks are respectively distributed on the side of the first plate and the side of the second plate, and the threaded racks are threadedly connected to the adjustment knob; by turning the adjustment knob, the first plate and the second plate can be controlled to move toward or away from each other, thereby changing the distance between the first plate and the second plate, thereby adjusting the width of the slurry flow channel; The rotating base, the upper sealing ring, the lower sealing ring and the base are fixedly connected, and inlet / outlet plates are respectively provided on both sides of the flow channel plate, the upper part of the inlet / outlet plate is fixed to the rotating base, and the lower part is fixed to the base; the inlet / outlet sealing ring is padded between the inlet / outlet plate and the upper sealing ring, the flow channel plate and the lower sealing ring; the inlet / outlet plate and the inlet / outlet sealing ring are sealed with inlet / outlet pipes; the two inlet / outlet pipes are respectively connected to the two ends of the slurry flow channel, one serving as an inlet pipe and the other as an outlet pipe, so as to realize the inflow and outflow of positive electrode slurry.

2. The electrochemical cell for in-situ testing of a slurry battery with adjustable flow channel according to claim 1, characterized in that: The window adjustment plate is a circular plate structure, the diameter of its upper half is larger than the diameter of its lower half; the rotating base is a plate structure with a circular inner hole, and its thickness is the same as the thickness of the upper half of the window adjustment plate; the inner diameter of the rotating base matches the diameter of the upper half of the window adjustment plate, so as to enable the window adjustment plate to be inserted into the rotating base.

3. The electrochemical cell for in-situ testing of a slurry battery with adjustable flow channel according to claim 1, characterized in that: The contact portions between the upper sealing ring, the window regulating plate and the flow channel plate are coated with vacuum grease.

4. The electrochemical cell for in-situ testing of a slurry battery with adjustable flow channels according to claim 1, characterized in that: The material of the Raman window is one of quartz, borosilicate glass, sapphire, and polymethyl methacrylate; the material of the first XRD window is metal beryllium, and the material of the second XRD window is polyimide.

5. The electrochemical cell for in-situ testing of a slurry battery with adjustable flow channel according to claim 1, characterized in that: The Raman window, the first XRD window and the second XRD window are evenly distributed on the window adjustment plate.

6. The electrochemical cell for in-situ testing of a slurry battery with adjustable flow channels according to claim 1, characterized in that: The shape of the slurry flow channel is one of a straight line, a meander, an S-shaped structure, an interdigitated shape, and a bionic structure.

7. The electrochemical cell for in-situ testing of a slurry battery with adjustable flow channels according to claim 1, characterized in that: Mounting brackets are connected to both sides of the base respectively, and the mounting brackets are fixedly connected to the adjusting knob at the height of the flow channel plate.

8. The electrochemical cell for in-situ testing of a slurry battery with adjustable flow channels according to claim 1, characterized in that: The fixed connection among the rotating base, the upper sealing ring, the lower sealing ring and the base is one of bolt connection, rivet connection, punch riveting, hook connection and bite seam connection.

9. The electrochemical cell for in-situ testing of a slurry battery with adjustable flow channels according to claim 8, characterized in that: The rotating base, the upper sealing ring, the lower sealing ring and the base are respectively provided with circular through holes at the four corners, and the four fixing bolts are inserted into the circular through holes and fixed with nuts; and the flow channel plate is respectively provided with long holes at the four corners, and the length direction of the long holes extends along the moving direction of the first plate body and the second plate body, and the width of the long holes matches the diameter of the fixing bolts.

10. The electrochemical cell for in-situ testing of a slurry battery with adjustable flow channels according to claim 1, characterized in that: The adjustment column, the window adjustment plate, the rotating base, and the base are made of one of polytetrafluoroethylene, polymethyl methacrylate, polyethylene terephthalate, polycarbonate, and polyformaldehyde resin; the negative electrode current collector is made of one of aluminum, copper, titanium, nickel, and stainless steel; the upper sealing ring and the lower sealing ring are made of one of silicone, nitrile rubber, isoprene rubber, and ethylene propylene rubber.

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