Experimental device

Abstract

An experimental device is used for testing the lithium ion transference number of a lithium ion battery and comprises a first shell and a placement table, an accommodating groove is formed in the first shell, and a first positioning groove is formed in the bottom wall of the accommodating groove; the placing table is contained in the containing groove, a second positioning groove is formed in the end face of the placing table, the first positioning groove is opposite to the second positioning groove, the first positioning groove is used for containing the first lithium sheet, and the second positioning groove is used for containing the second lithium sheet. The symmetrical lithium battery prepared by the experimental device is good in symmetry.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to an experimental device. Background Art

[0002] The purpose of the lithium ion migration number experiment of lithium batteries is to evaluate the ion transport capacity of the electrolyte in the lithium battery and further evaluate the electrochemical performance of the lithium battery. By measuring the migration number of ions, important parameters such as the ionic conductivity, electrochemical stability, and lithium ion transport performance of the electrolyte can be further studied. These parameters have an important influence on the performance of the battery, including the energy density, charge and discharge rate, and battery life of the battery. Therefore, through the lithium ion migration number experiment of lithium batteries, we can gain an in-depth understanding of the ion transport mechanism of the electrolyte and the electrochemical performance of the battery, providing important experimental basis and guidance for improving and optimizing the performance of the battery.

[0003] The lithium ion migration number test of lithium batteries is usually carried out using lithium symmetric batteries. The lithium symmetric batteries prepared by existing experimental devices have poor symmetry, resulting in large deviation values ​​of experimental data. Utility Model Content

[0004] The utility model aims to provide an experimental device to solve the problem of poor symmetry of lithium symmetrical batteries prepared by the existing experimental device.

[0005] In order to achieve the purpose of the utility model, the utility model provides the following technical solutions:

[0006] The utility model provides an experimental device for testing the lithium ion migration number of a lithium ion battery, comprising:

[0007] The first housing is provided with a receiving groove, and the bottom wall of the receiving groove is provided with a first positioning groove;

[0008] The placing table is received in the receiving groove, and a second positioning groove is provided on the end surface of the placing table. The first positioning groove is opposite to the second positioning groove. The first positioning groove is used to receive the first lithium sheet, and the second positioning groove is used to receive the second lithium sheet.

[0009] In one embodiment, the first shell and the placement table are both conductive components, and the experimental device also includes an insulating sleeve, which is accommodated in the accommodating groove. The insulating sleeve has a center hole, which is connected to the first positioning groove, and the placement table is accommodated in the center hole.

[0010] In one embodiment, the first shell, the placement table and the insulating sleeve are all rotating bodies that are rotationally symmetrical around a first axis, the insulating sleeve is slidingly connected to the inner circumferential wall of the accommodating groove in the axial direction of the first axis, and the placement table is slidingly connected to the inner circumferential wall of the center hole in the axial direction of the first axis.

[0011] In one embodiment, the experimental device further includes a second shell, the second shell is connected to the placement table, the second shell is also connected to the first shell, the first shell and the second shell are spaced apart, and the second shell is a conductive component.

[0012] In one embodiment, the placement platform is movably connected to the second shell in the axial direction of the first axis.

[0013] In one embodiment, the placement platform includes a placement portion and a connecting rod that are coaxially connected, the second positioning groove is opened on the end surface of the placement portion away from the connecting rod, the outer peripheral surface of the end of the connecting rod away from the placement portion is provided with a first thread, the second shell is provided with a mounting hole, the inner peripheral wall of the mounting hole is provided with a second thread, and the first thread and the second thread are matched and connected.

[0014] In one embodiment, a first groove is formed on an end surface of the first shell facing the second shell, and / or a second groove is formed on an end surface of the second shell facing the first shell;

[0015] The experimental device further comprises a sealing member, wherein the sealing member is partially received in the first groove and / or partially received in the second groove.

[0016] In one embodiment, the first shell includes a coaxially connected column portion and a disk portion, the disk portion is arranged on the outer circumferential surface of the column portion, and the experimental device also includes a fastener, which connects the disk portion and the second shell.

[0017] In one embodiment, the fastener includes a screw, a nut and a gasket, the gasket is arranged between the disk body and the second shell, the screw passes through the disk body, the gasket and the second shell, and the nut is connected to the screw.

[0018] In one embodiment, the experimental device further includes a first pole lug and a second pole lug, wherein the first pole lug is connected to the first shell, and the second pole lug is connected to the second shell.

[0019] The utility model is provided with a first shell and a placement table, the first shell is provided with a first positioning groove for accommodating a first lithium sheet, the placement table is provided with a second positioning groove for accommodating a second lithium sheet, the first positioning groove and the second positioning groove are arranged relatively to each other and limit the movement of the first lithium sheet and the second lithium sheet, so that the placement positions of the first lithium sheet and the second lithium sheet are symmetrical, thereby making the prepared lithium symmetrical battery have good symmetry, ensuring that the experimental results will not be affected by the symmetry problem of the lithium battery during the test process, and making the data stability of the experimental results good. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 is an exploded view of an experimental device of an embodiment;

[0022] Figure 2 is a side view of an experimental device of an embodiment;

[0023] Figure 3 is a top view of a first housing of an embodiment;

[0024] Figure 4 is a line graph of the number of lithium ion migration measured using a button battery fixture according to an embodiment;

[0025] Figure 5 The figure is a line graph of the lithium ion migration number measured by using an experimental device according to an embodiment.

[0026] Description of reference numerals:

[0027] 100-experimental device, 10-first shell, 11-accommodating groove, 12-first positioning groove, 13-first groove, 14-column portion, 15-disk portion, 16-first receiving hole, 17-first fastening hole, 20-placing table, 21-second positioning groove, 22-placing portion, 23-connecting rod, 231-first thread, 30-insulating sleeve, 31-center hole, 40-second shell, 41-mounting hole, 42-second groove, 43-second receiving hole, 44-second fastening hole, 50-seal, 60-fastener, 61-screw, 62-nut, 63-gasket, 631-third fastening hole, 70-first pole ear, 80-second pole ear, 90-mounting member, a-first axis. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there can be a central component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time.

[0030] Unless otherwise defined, all technical and scientific terms used in this utility model have the same meaning as those commonly understood by technicians in the technical field of this utility model. The terms used in the specification of this utility model are only for the purpose of describing specific embodiments and are not intended to limit this utility model. The term "and / or" used in this utility model includes any and all combinations of one or more related listed items.

[0031] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0032] When assembling lithium symmetrical batteries, a glove box with lower water and oxygen content is required. However, it is extremely difficult to ensure the symmetry of the lithium sheets on both sides when operating in the glove box, and it is also easy to cause the lithium sheets to shift when sealing the battery. When measuring the lithium ion migration number, it takes a long time to reach a steady state, and the process is not stable.

[0033] For reference Figure 1 and Figure 2 The utility model provides an experimental device 100 for testing the lithium ion migration number of a lithium ion battery, comprising a first shell 10 and a placement table 20. The first shell 10 is provided with a receiving groove 11, and the bottom wall of the receiving groove 11 is provided with a first positioning groove 12. The placement table 20 is received in the receiving groove 11, and the end surface of the placement table 20 is provided with a second positioning groove 21, the first positioning groove 12 and the second positioning groove 21 are opposite, the first positioning groove 12 is used to receive a first lithium sheet, and the second positioning groove 21 is used to receive a second lithium sheet.

[0034] The end surface of the first housing 10 is a flat horizontal end surface, which prevents the experimental device 100 from tilting.

[0035] The cross section of the first housing 10 can be rectangular, circular, etc., without limitation. The bottom wall of the receiving groove 11 can be rectangular, circular, etc., without limitation. The bottom walls of the first positioning groove 12 and the second positioning groove 21 can be rectangular, circular, etc.

[0036] The inner wall of the first positioning groove 12 can be inclined relative to the inner wall of the receiving groove 11, or can be parallel to the inner wall of the receiving groove 11, without limitation. Correspondingly, the inner wall of the second positioning groove 21 can be inclined relative to the inner wall of the receiving groove 11, or can be parallel to the inner wall of the receiving groove 11.

[0037] In one embodiment, the depth of the first positioning groove 12 is h1, and the thickness of the first lithium sheet is h2, which satisfies: 0.9h2≤h1≤0.95h2. When h1<0.9h2, the height of the first lithium sheet protruding from the first positioning groove 12 is too high, and during the process of the first lithium sheet being stressed, it may cause uneven stress on the first lithium sheet itself and cause significant deformation; when h1>0.95h2, the height of the first lithium sheet exposed from the first positioning groove 12 is too small, or the first lithium sheet is not exposed from the first positioning groove 12.

[0038] A separator is further arranged between the first lithium sheet and the second lithium sheet. The separator may be any one of a woven membrane, a non-woven membrane (non-woven fabric), a microporous membrane, a composite membrane, a rolled membrane, etc., without limitation.

[0039] In one embodiment, the experimental device 100 further includes a heightening member. If the thickness of the first lithium sheet is too small, the heightening member is disposed on the bottom wall of the first positioning groove 12 and the second positioning groove 21, so that the first lithium sheet and the second lithium sheet can be partially exposed in the first positioning groove 12 and the second positioning groove 21, so that when preparing a lithium symmetrical battery, the first lithium sheet and the second lithium sheet are subjected to the same force, so that the lithium symmetrical battery has good symmetry and the error is less than 0.1%.

[0040] The first lithium sheet and the second lithium sheet are made of high-purity metallic lithium to ensure the accuracy and stability of the test. The surfaces of the first lithium sheet and the second lithium sheet are also polished to remove impurities and oxides to ensure good contact with the electrolyte. The thickness and weight of the first lithium sheet and the second lithium sheet are uniform to ensure the repeatability and comparability of the test results.

[0041] The utility model is provided with a first shell 10 and a placement table 20, the first shell 10 is provided with a first positioning groove 12 for accommodating a first lithium sheet, the placement table 20 is provided with a second positioning groove 21 for accommodating a second lithium sheet, the first positioning groove 12 and the second positioning groove 21 are arranged relatively to each other and limit the movement of the first lithium sheet and the second lithium sheet, so that the placement positions of the first lithium sheet and the second lithium sheet are symmetrical, so that the prepared lithium symmetrical battery has good symmetry, ensuring that the experimental results will not be affected by the symmetry problem of the lithium battery during the test process.

[0042] For reference Figure 1and Figure 2 In one embodiment, the first shell 10 and the placement table 20 are both conductive components. The experimental device 100 also includes an insulating sleeve 30, which is accommodated in the accommodating groove 11. The insulating sleeve 30 has a center hole 31, which is connected to the first positioning groove 12, and the placement table 20 is accommodated in the center hole 31.

[0043] The material of the insulating sleeve 30 can be glass fiber, silicone rubber glass fiber, polytetrafluoroethylene (PTFE), nylon, etc., without limitation.

[0044] The first housing 10 and the placement platform 20 can be made of aluminum, aluminum alloy, copper, copper alloy, iron, etc. The first housing 10 is a conductive member, so that the first housing 10 serves as a current collector and a shell of the battery, simplifying the assembly process of the battery.

[0045] The insulating sleeve 30 is mainly used to isolate the first housing 10 and the placement table 20 to avoid short circuit. At the same time, the center hole 31 can provide a guide for the placement table 20 during the installation of the experimental device 100, so that the second lithium sheet in the second positioning groove 21 and the first lithium sheet in the first positioning groove 12 can be placed smoothly.

[0046] In one embodiment, the first shell 10, the placement table 20 and the insulating sleeve 30 are all rotationally symmetrical bodies around the first axis a, the insulating sleeve 30 is slidably connected to the inner circumferential wall of the accommodating groove 11 in the axial direction of the first axis a, and the placement table 20 is slidably connected to the inner circumferential wall of the center hole 31 in the axial direction of the first axis a.

[0047] The insulating sleeve 30 has a small surface roughness and is tightly matched with the inner peripheral wall of the receiving groove 11 .

[0048] The first shell 10, the placement table 20 and the insulating sleeve 30 are rotationally symmetrical bodies around the first axis a, which can simplify the overall structure of the experimental device 100 and facilitate production and manufacturing. At the same time, it can facilitate assembly by experimenters and improve experimental efficiency.

[0049] In one embodiment, the experimental device 100 further includes a second shell 40 , which is connected to the placement table 20 . The second shell 40 is also connected to the first shell 10 , and the first shell 10 and the second shell 40 are spaced apart. The second shell 40 is a conductive component.

[0050] The second shell 40 and the placement table 20 can be an integrated structure, that is, an integrated structure prepared by an integrated process, and the integrated process can specifically be stamping, casting, etc. The second shell 40 and the placement table 20 can also be a split structure, and the connection method between the second shell 40 and the placement table 20 can be screw connection, clamping connection, etc., without limitation.

[0051] The second housing 40 can be made of aluminum, aluminum alloy, copper, copper alloy, iron, etc. The second housing 40 is a conductive member, which can act as a current collector and a shell of the battery together with the first housing 10, simplifying the assembly process of the battery.

[0052] The cross section of the second shell 40 can be rectangular, circular, etc., without limitation.

[0053] The first shell 10 and the second shell 40 are spaced apart to avoid short circuit. The second shell 40 is connected to the placement table 20 and can be used to apply pressure to the first lithium sheet and the second lithium sheet.

[0054] In one embodiment, the placement platform 20 is movably connected to the second shell 40 in the axial direction of the first axis a.

[0055] The battery assembly needs to be performed in a glove box, and the placement table 20 and the second shell 40 are movably connected, so that the weight of a single component is reduced, making it easier for experimenters to operate.

[0056] For reference Figure 1 and Figure 2 In one embodiment, the placement table 20 includes a placement portion 22 and a connecting rod 23 that are coaxially connected, the second positioning groove 21 is opened on the end surface of the placement portion 22 away from the connecting rod 23, and the outer peripheral surface of the end of the connecting rod 23 away from the placement portion 22 is provided with a first thread 231, the second shell 40 is provided with a mounting hole 41, and the inner peripheral wall of the mounting hole 41 is provided with a second thread, and the first thread 231 and the second thread are matched and connected.

[0057] The mounting hole 41 may penetrate the second housing 40 in the axial direction of the first axis a, or may be a blind hole, that is, not penetrating the second housing 40 , without limitation.

[0058] The pressure on the lithium sheet can be changed according to the experimental design by adjusting the screwing depth of the connecting rod 23 into the second shell 40, that is, adjusting the matching length of the first thread 231 and the second thread, so as to change the pressure on the lithium sheet, making the operation simple and enabling repeated experiments.

[0059] For reference Figure 2 and Figure 3 In one embodiment, the first housing 10 has a first groove 13 formed on the end surface facing the second housing 40, and / or the second housing 40 has a second groove 42 formed on the end surface facing the first housing 10. The experimental device 100 further includes a sealing member 50, which is partially received in the first groove 13 and / or partially received in the second groove 42.

[0060] The first groove 13 may be communicated with the receiving groove 11 , or may be spaced apart from the receiving groove 11 , without limitation.

[0061] The sealing ring may be a nitrile rubber (NBR) sealing ring, a hydrogenated nitrile rubber (HNBR) sealing ring, a silicone rubber (SIL) sealing ring, a fluorine rubber (VITON) sealing ring, a fluorosilicone rubber (FLS) sealing ring, an ethylene propylene diene rubber (EPDM) sealing ring, a chloroprene rubber (CR) sealing ring, a butyl rubber (IIR) sealing ring, etc., without limitation.

[0062] There can be one seal 50 or two seals. When there is one seal 50, a part of the seal 50 is accommodated in the first groove 13, and the other part is accommodated in the second groove 42. When there are two seals 50, the seals 50 are a first seal 50 and a second seal 50. The first seal 50 is accommodated in the first groove 13, and the second seal 50 is accommodated in the second groove 42. The first seal 50 and the second seal 50 are used together to improve the sealing performance of the experimental device 100, and multiple repeated experiments can be carried out.

[0063] For reference Figure 1 In one embodiment, the first shell 10 includes a coaxially connected column portion 14 and a disk portion 15 , the disk portion 15 is arranged on the outer circumferential surface of the column portion 14 , and the experimental device 100 also includes a fastener 60 , which connects the disk portion 15 and the second shell 40 .

[0064] The first shell 10 can be an integrated structure, that is, the column portion 14 and the disk portion 15 are an integrated structure prepared by an integrated process, and the integrated process can specifically be stamping, casting, etc. The column portion 14 and the disk portion 15 can also be a split structure, and the column portion 14 and the disk portion 15 can be connected by screwing, clamping, bonding, welding, etc., without limitation.

[0065] The fastener 60 can be a threaded member or a clamping member, without limitation.

[0066] There can be multiple fasteners 60, which can be arranged at equal intervals on the disk body 15 and the second shell 40. Specifically, there can be 3, 4, 5, etc. fasteners.

[0067] The disk is disposed on the outer circumferential surface of the column portion 14 , which can facilitate the experimenter to move and assemble the experimental device 100 .

[0068] For reference Figure 1 In one embodiment, the fastener 60 includes a screw 61, a nut 62 and a gasket 63, the gasket 63 is arranged between the disk body 15 and the second shell 40, the screw 61 passes through the disk body 15, the gasket 63 and the second shell 40, and the nut 62 is connected to the screw 61.

[0069] The gasket 63 mainly serves to isolate the first housing 10 from the second housing 40 to avoid short circuit. The gasket 63 can be rubber, polyethylene terephthalate (PET) insulating gasket 63, nylon insulating gasket 63, polycarbonate (PC) insulating gasket 63, etc., without limitation.

[0070] The disk body 15 is provided with a plurality of first fastening holes 17 , and the second shell 40 is provided with a plurality of second fastening holes 44 . The first fastening holes 17 and the second fastening holes 44 are provided correspondingly. The gasket 63 is provided with a third fastening hole 631 .

[0071] Each screw 61 passes through the first fastening hole 17 , the third fastening hole 631 of the gasket 63 , and the second fastening hole 44 , and is connected and fixed with the corresponding nut 62 .

[0072] The fastener 60 is used to strengthen the structural strength of the experimental device 100 and also to apply pressure to the lithium sheet.

[0073] For reference Figure 1 In one embodiment, the experimental device 100 further includes a first pole tab 70 and a second pole tab 80 , wherein the first pole tab 70 is connected to the first shell 10 , and the second pole tab 80 is connected to the second shell 40 .

[0074] The experimental device 100 further includes a plurality of mounting members 90. A first receiving hole 16 is formed on the first housing 10, a second receiving hole 43 is formed on the second housing 40, the first pole tab 70 is fixed to the first housing 10 through the mounting member 90 and the first receiving hole 16, and the second pole tab 80 is fixed to the second housing 40 through the mounting member 90 and the second receiving hole 43. The mounting member 90 may be a threaded member, and the corresponding first receiving hole 16 and second receiving hole 43 are threaded holes.

[0075] The material of the first electrode tab 70 and the second electrode tab 80 can be aluminum, nickel, copper, copper plated with nickel, etc., without limitation.

[0076] The lengths of the first electrode tab 70 and the second electrode tab 80 should not be too long to avoid accidental short-circuiting of the positive and negative electrodes during operation, thereby causing a short circuit.

[0077] The first pole tab 70 and the second pole tab 80 are disposed on opposite sides of the first axis a in the radial direction to avoid short-circuiting the positive and negative poles by mistake during operation.

[0078] When the first shell 10, the placement table 20 and the second shell 40 are conductive parts, the first pole tab 70 and the first shell 10 and the second pole tab 80 and the second shell 40 are directly connected, and the connection method with the first lithium sheet and the second lithium sheet is indirect connection; when the first shell 10, the placement table 20 and the second shell 40 are not conductive parts, the first pole tab 70 and the second pole tab 80 are directly connected to the first lithium sheet and the second lithium sheet.

[0079] The first pole tab 70 and the second pole tab 80 can connect the battery to an external circuit to achieve current transmission. At the same time, the first pole tab 70 and the second pole tab 80 have good electrical conductivity, which can ensure that the current flows smoothly inside the battery, reduce resistance, and improve the electrical conductivity of the battery.

[0080] In the process of using the experimental device 100 of the utility model, the large deadweight of the experimental device 100 can be stabilized on the desktop during the assembly process, and the first lithium sheet, the diaphragm and the second lithium sheet are added to the receiving groove 11 of the first shell 10 in turn, and finally the first shell 10 and the second shell 40 are fixed by the fastener 60. The operation is simple and stable, and will not cause the lithium sheet to shift, thereby ensuring the symmetry of the first lithium sheet and the second lithium sheet, which can improve the consistency of the experiment and ensure the accuracy of the experiment.

[0081] The experimental device 100 of the utility model is used to perform steady-state current method test and calculate the lithium ion migration number through the obtained data: the first step is to perform electrochemical impedance spectroscopy (EIS) test to measure R0; the second step is to apply a small and constant potential difference Δ (generally about 10mV) to the experimental device 100, record the change of current over time, and record the current values ​​before and after the voltage is applied, which are I0 and I ss ; The third step is to conduct electrochemical impedance spectroscopy test after entering the steady state to measure R ss ; Step 4: Calculate the lithium ion migration number by using the formula:

[0082]

[0083] Figure 4 This is a data graph of the lithium ion migration number measured using an existing button battery fixture. Figure 5 1 is a data graph of the lithium ion migration number measured using the experimental device 100 of the present invention. Figure 4 It can be seen that after the clamp reaches the steady state time, there are many violent fluctuations, which is extremely unstable. The lithium ion migration numbers of the five tests are 0.467, 0.483, 0.511, 0.241, and 0.203, respectively. The calculated variance is 0.021496, and the consistency of the data is poor. Figure 5 It can be seen that after the experimental device 100 of the present invention reaches the steady-state time, the fluctuation of the data is very small, the overall data curve is stable, the lithium ion migration numbers of the five tests are 0.162, 0.175, 0.211, 0.148, and 0.160, respectively, and the calculated variance is 0.000586. The experimental data has good consistency and high repeatability.

[0084] By comparing the data graphs of the lithium ion migration number, it can be obtained that the data of the lithium ion migration number measured using the experimental device 100 of the utility model is more stable, the experimental repeatability is high, and the experimental device 100 of the utility model has a simple structure and is easy to operate, which is beneficial for experimenters to assemble and test in the glove box, thereby improving the experimental efficiency.

[0085] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" are based on the orientation or positional relationship described 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 referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0086] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. An experimental device for testing the lithium ion migration number of a lithium ion battery, characterized in that: include: The first housing is provided with a receiving groove, and the bottom wall of the receiving groove is provided with a first positioning groove; The placing table is accommodated in the containing groove, and the end surface of the placing table is provided with a second positioning groove, the first positioning groove and the second positioning groove are opposite to each other, the first positioning groove is used to accommodate the first lithium sheet, and the second positioning groove is used to accommodate the second lithium sheet.

2. The experimental device according to claim 1, characterized in that: The first shell and the placement table are both conductive components. The experimental device also includes an insulating sleeve, which is accommodated in the accommodating groove. The insulating sleeve has a center hole, which is connected to the first positioning groove, and the placement table is accommodated in the center hole.

3. The experimental device according to claim 2, characterized in that: The first shell, the placement table and the insulating sleeve are all rotating bodies with rotational symmetry around a first axis. The insulating sleeve is slidably connected to the inner circumferential wall of the accommodating groove in the axial direction of the first axis, and the placement table is slidably connected to the inner circumferential wall of the center hole in the axial direction of the first axis.

4. The experimental device according to claim 3, characterized in that: The experimental device further includes a second shell, the second shell is connected to the placement table, the second shell is also connected to the first shell, the first shell and the second shell are spaced apart, and the second shell is a conductive component.

5. The experimental device according to claim 4, characterized in that: The placement platform is movably connected to the second shell in the axial direction of the first axis.

6. The experimental device according to claim 5, characterized in that: The placement platform includes a placement portion and a connecting rod that are coaxially connected, the second positioning groove is opened on the end surface of the placement portion away from the connecting rod, the outer peripheral surface of one end of the connecting rod away from the placement portion is provided with a first thread, the second shell is provided with a mounting hole, the inner peripheral wall of the mounting hole is provided with a second thread, and the first thread and the second thread are matched and connected.

7. The experimental device according to claim 4, characterized in that: The end surface of the first shell facing the second shell is provided with a first groove, and / or the end surface of the second shell facing the first shell is provided with a second groove; The experimental device further comprises a sealing member, wherein the sealing member is partially received in the first groove and / or partially received in the second groove.

8. The experimental device according to claim 4, characterized in that: The first shell includes a coaxially connected column and a disk, wherein the disk is disposed on the outer circumferential surface of the column. The experimental device also includes a fastener, wherein the fastener connects the disk and the second shell.

9. The experimental device according to claim 8, characterized in that: The fastener includes a screw, a nut and a gasket, wherein the gasket is arranged between the disk body and the second shell, the screw passes through the disk body, the gasket and the second shell, and the nut is connected to the screw.

10. The experimental device according to claim 4, characterized in that: The experimental device further includes a first pole lug and a second pole lug, wherein the first pole lug is connected to the first shell, and the second pole lug is connected to the second shell.

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