Electrochemical parameter testing device

Abstract

The invention discloses a testing device for testing electrochemical parameters. The testing device comprises a pressure applying assembly, a to-be-tested sample containing assembly, a testing assembly and a control unit, the to-be-tested sample containing assembly comprises a plurality of testing cavities and liquid containing cavities which are arranged in one-to-one correspondence with the testing cavities; the liquid accommodating cavity and the test cavity are in liquid communication and solid-phase separation; the pressure applying assembly comprises a plurality of pressure pushing pieces which are in one-to-one correspondence with the testing cavities, and the pressure pushing pieces can be in compression joint with the samples to be tested in the corresponding testing cavities and can apply pressure to the samples to be tested. The testing device disclosed by the invention is provided with a plurality of testing stations, and can test a plurality of samples to be tested at the same time, so that the testing efficiency is improved, and meanwhile, the testing error is reduced. Meanwhile, the electrochemical test of a solid material and the electrochemical test of each material in a liquid battery can be covered.

Description

Technical Field

[0001] The present application relates to the field of testing technology, and in particular to a testing device for testing electrochemical parameters. Background Art

[0002] With the rapid development of new energy technologies, lithium-ion batteries and solid-state batteries have become the main direction of current and future energy development. Among them, various types of electrode materials, diaphragm materials and solid electrolytes have become the hot spots and focuses of related research. The development and screening of suitable electrode materials, diaphragm materials and solid electrolytes have become an important part of battery development and production.

[0003] For these potentially useful materials, testing of electrochemical parameters is essential. Current testing devices generally perform single-point testing on a single material. This is not only inefficient, but if multiple tests are required, the test error may also increase due to different test parameters. Summary of the invention

[0004] In order to solve the above problems, the present application discloses a testing device, which may include multiple testing stations and can test multiple samples at the same time.

[0005] The test device for testing electrochemical parameters disclosed in the present application may include: a pressure-applying component, a component for holding a sample to be tested, a test component and a control unit; wherein the component for holding the sample to be tested includes a plurality of test cavities, each of which can accommodate a sample to be tested; the pressure-applying component includes a plurality of pressure push pieces corresponding to the test cavities one by one, the pressure push pieces can press the samples to be tested in the corresponding test cavities, and can apply pressure to the samples to be tested; the test component can be electrically connected to the samples to be tested through the pressure push pieces, and can perform an electrochemical test on at least one of the samples to be tested; the control unit is electrically connected to the pressure-applying component and the test component, and the control unit can drive the pressure-applying component and can control the test component to perform an electrochemical test on at least one sample to be tested.

[0006] According to some embodiments of the present application, the pressure-applying assembly further includes a drive motor electrically connected to the control unit; and a hydraulic unit transmission-connected to the drive motor and the pressure-applying assembly; wherein the drive motor drives the hydraulic unit and pushes the pressure push plate to move through the hydraulic unit.

[0007] According to some embodiments of the present application, the sample holding component further includes: a plurality of liquid containing cavities, which are arranged one-to-one corresponding to the plurality of test cavities; wherein the liquid containing cavities are in liquid communication with the corresponding test cavities and are solid-phase blocked.

[0008] According to some embodiments of the present application, the sample holding component to be tested also includes: a permeable film; a conducting hole is arranged between the liquid containing cavity and the corresponding test cavity, and the permeable film is sealed on the conducting hole; wherein, the liquid containing cavity and the corresponding test cavity are in liquid communication through the permeable film.

[0009] According to some embodiments of the present application, the permeable film is arranged on the inner wall of the liquid containing chamber and seals the conducting hole; and / or, the permeable film is arranged on the inner wall of the test chamber and seals the conducting hole; preferably, a thermal insulation pad is arranged on one or more inner walls of the liquid containing chamber.

[0010] According to some embodiments of the present application, the pressure push piece includes a pressure state and a retracted state. When in the pressure state, the pressure push piece can apply pressure to the sample to be tested, and the liquid in the test cavity can enter the liquid containing cavity through the permeable membrane; when in the retracted state, the pressure push piece can be retracted in the direction opposite to the force application direction, and the liquid in the liquid containing cavity can enter the test cavity through the permeable membrane.

[0011] According to some embodiments of the present application, a first pole piece is arranged on the surface of the pressure push plate opposite to the sample to be tested, a second pole piece is arranged at the bottom end of the test cavity, and the sample to be tested is connected between the first pole piece and the second pole piece to form a battery module to be tested; preferably, the test component includes an electrochemical workstation, the electrochemical workstation is electrically connected to the control unit, and the electrochemical workstation is electrically connected to the first pole piece and the second pole piece, and the electrochemical workstation performs corresponding electrochemical tests on the battery module to be tested according to the control signal of the control unit.

[0012] According to some embodiments of the present application, the testing device also includes a temperature control component, which is electrically connected to the control unit, and the control unit can control the heating or cooling of the temperature control component; the temperature control component includes an incubator, a heating unit, a cooling unit and a heat preservation unit; the sample holding component to be tested is arranged in the incubator, and the outer walls of the multiple test cavities are sequentially coated with the heating unit, the heat preservation unit and the cooling unit from the inside to the outside, and the heat preservation unit is provided at the bottom of the multiple test cavities.

[0013] According to some embodiments of the present application, the testing device also includes a data monitoring component, which is electrically connected to the control unit, and the control unit can obtain monitoring data of the data monitoring component; the data monitoring component includes a fixed temperature sensor and a non-fixed temperature sensor; the non-fixed temperature sensor is fixedly connected to the pressure push piece and can move along the inner wall of the test cavity with the pressure push piece; the fixed temperature sensor is fixed on the inner wall of the test cavity and is arranged near the bottom of the test cavity; preferably, the data monitoring component also includes a pressure sensor, and the pressure-applying assembly also includes a mounting seat and an insulating gasket, the pressure sensor is arranged between the mounting seat and the insulating gasket, and the pressure push piece is arranged on the other side of the insulating gasket.

[0014] According to some embodiments of the present application, the control unit includes one or more of a CPU, an MCU and a PLC; preferably, the electrochemical parameters include one or more of conductivity, tortuosity, diffusion coefficient and exchange current density; preferably, the test component is capable of performing electrochemical tests on a plurality of the samples to be tested, wherein the plurality of the samples to be tested are the same or different, and the plurality of the electrochemical tests are the same or different.

[0015] The test device for testing electrochemical parameters disclosed in the present application is equipped with multiple test chambers for synchronously testing multiple samples to be tested at the same time, and is equipped with corresponding multiple liquid containing chambers, and can add electrolyte to test the electrochemical properties of the material. It can simultaneously realize solid material parameter testing and liquid battery simulation testing, covering a wider range of material testing. At the same time, the ability to test multiple samples to be tested at the same time improves the test efficiency. And it can provide the same test parameters for each sample to be tested, reducing the test error.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present application will be further described in the form of exemplary embodiments, which will be described in detail by way of the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

[0018] Figure 1 is an exemplary structural diagram of a testing device for testing electrochemical parameters according to some embodiments of the present application;

[0019] Figure 2 is an exemplary structural diagram of a liquid containing chamber according to some embodiments of the present application;

[0020] Figure 3is an exemplary equivalent circuit diagram of a battery according to some embodiments of the present application;

[0021] Figure 4 The conductivity test results under different pressures are shown;

[0022] Figure 5 The tortuosity test results at different pressures at the test temperature are shown;

[0023] Figure 6 The diffusion coefficient test results under the test temperature and test pressure are shown;

[0024] Figure 7 The exchange current density test results at different SOCs are shown. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0026] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by technicians in the technical field of this application. The terms used in this application and in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The words "including" or "comprising" and the like used in this application mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The terms "and / or" or "and / or" used in this application include any and all combinations of one or more related listed items.

[0027] The terms "including", "having" and their cognates used in this application are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0028] It should be noted that the terms "first", "second", "third", etc. used in this application are only used to distinguish descriptions and should not be understood as indicating or implying relative importance. When a component is referred to as being "fixed to", "mounted on" or "disposed on" another component, it can be directly on the other component or there can also be other components centered. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there can be other components centered at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0029] Some preferred embodiments of the present application are described below. It should be noted that the following description is for the purpose of illustration and is not intended to limit the scope of protection of the present application. The steps involved in the present application can be performed accurately in sequence, or various steps can be processed in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or one or more operations can be removed from these processes.

[0030] The present application discloses a testing device for testing electrochemical parameters, which is equipped with multiple testing chambers and corresponding multiple liquid containing chambers. Electrolyte can be added to test the electrochemical properties of materials, thereby achieving both electrochemical testing of solid materials and liquid battery simulation testing, expanding the range of material testing, and providing more accurate test results.

[0031] The test device provided in the present application may include a pressure component, a sample holding component to be tested, a test component and a control unit. The sample holding component to be tested may include a test cavity, and each test cavity may respectively accommodate a sample to be tested. The sample to be tested may include a lithium-ion battery or a solid electrolyte composed of a lithium battery separator prepared based on various materials. The material may exemplarily include polymers such as polyethylene (PE), polypropylene (PP), polyimide (PI), etc. for lithium battery separators or their composites or surface modified / coated or added with additives, lithium ion oxides such as LLZO, LLTO, LAGP, LATP, LBSPO, LPO, Li4SiO4, Li2ZnTi3O8, etc. for solid electrolytes, lithium ion sulfides such as Li2S, LiPS, LPSC, LiPON, etc., lithium ion phosphates Li3PO4, LiFePO4, etc., lithium ion halides such as LiCl, LiBr, etc., polymers such as poly (ethylene oxide) (PEO)-based polymers, etc., or composite materials composed of one or more materials. The test cavity can be provided by a hollow cylindrical body with one end open, for example, a cylinder, a square body, etc. The sample to be tested can be placed in the hollow cylindrical body and an electrochemical parameter test can be performed. In some feasible embodiments, the sample to be tested can be a block or a powder / particle. When the sample to be tested is a block, it can be modified into a shape that matches the inner diameter or cross-section of the test cavity, such as the same size and shape. In this way, under certain test conditions that require pressure testing, the sample to be tested will not undergo radial deformation due to pressure, thereby affecting the test results. When the sample to be tested is a powder / particle, there is no specific requirement for its shape. Multiple test cavities can accommodate multiple samples to be tested at the same time, so that parallel tests can be completed at the same time, thereby improving test efficiency.

[0032] The test sample holding component may also include a plurality of liquid containing chambers. They may be arranged in a one-to-one correspondence with the plurality of test chambers. An example may be that when the test chamber is a hollow cylindrical body as described above, the liquid containing chamber may be an annular chamber surrounding the peripheral wall of the test chamber, and the outer wall of the test chamber serves as the inner wall of the annular chamber. The liquid containing chamber may contain electrolyte, and is liquid-phase connected to the test chamber and solid-phase blocked. For example, a through hole is provided on the outer wall of the test chamber, and a diaphragm may be provided at the through hole to prevent the test sample from entering the liquid containing chamber and allow the electrolyte to enter and exit the test chamber, so as to participate in the composition of the liquid battery together with the test sample.

[0033] The pressure-applying assembly may include a plurality of pressure push pieces corresponding one to one with the test chamber. The pressure push piece may be disposed at the top end of the test chamber, for example, an open end, and reciprocate under external drive, for example, move along the axial direction of the test chamber toward the bottom end of the test chamber to apply pressure to the sample to be tested. A feasible implementation may be that the shape of the pressure push piece is the same as the cross-section of the test chamber. In this way, when pressure is applied to the sample to be tested, the sample to be tested will not partially overflow from the gap between the pressure push piece and the test chamber due to pressure, thereby affecting the test result. The power of all the pressure push pieces may come from a pneumatic pressure system or a hydraulic system, and the synchronous movement of the pressure push pieces is achieved through a diverter valve.

[0034] The temperature control component can be arranged around the sample holding component to be tested. For example, the temperature control component can include a heating / cooling / insulation unit surrounding each test cavity. A heating layer prepared by various heating coils such as resistance wires or induction coils embedded in various heat-conducting materials can be used as a heating unit, a cooling layer prepared by air-cooling pipes, liquid-cooling pipes, etc. embedded in various heat-conducting materials can be used as a cooling unit, and a heat-insulating layer prepared by various heat-insulating materials such as polyurethane foam, ceramic fiber, etc. can be used as an insulation unit. The temperature of the sample to be tested is regulated by controlling the on and off of the resistance wire / induction coil and the gas flow / coolant flow in the cooling pipe. The insulation unit isolates the heat exchange between the outside world and the sample to be tested to keep the temperature stable.

[0035] The data monitoring component may include a sensor for sensing the environmental data of the sample to be tested during the test, such as pressure, temperature, degree of deformation, etc. Exemplarily, the pressure can be measured by a pressure sensor arranged on the pressure push sheet. For example, the pressure sensor can be arranged on the bottom side of the pressure push sheet facing the sample to be tested. In this way, when the pressure push sheet presses against the sample to be tested, the pressure sensor is under pressure to obtain pressure data. The temperature can be obtained by a temperature probe arranged on the inner wall of the test cavity or the bottom side of the pressure push sheet, which is in direct contact with the sample to be tested, thereby obtaining temperature data. The degree of deformation can be measured by a displacement sensor, which can be used to obtain the displacement data of the pressure push sheet, thereby determining the height change of the sample to be tested compared to before pressure is applied.

[0036] The test component can be used to apply test electrical parameters to the test sample holding component and obtain feedback electrical parameters. For example, the bottom of the test cavity and the pressure push plate are both provided with electrode plates, and the test component can be electrically connected to the electrode plates through wires and send down corresponding voltages or currents. At the same time, the returned voltage V or current I signal is collected.

[0037] The control unit can be electrically connected to the pressure component, the data monitoring component, the temperature adjustment component, and the test component, and can be implemented in a wired manner (for example, a wire, etc.) or a wireless manner (for example, Bluetooth, infrared, etc.). The control unit transmits control signals to the above components. For example, a rotation instruction (for example, including a rotation speed, etc.) can be sent to the driving motor of the pneumatic pressure system or hydraulic system of the pressure component, and a heating or cooling instruction can be sent to the heating unit or cooling unit of the temperature adjustment component. At the same time, the control unit can confirm the electrochemical parameters based on the data received from the above components. For example, the control unit can determine the conductivity, tortuosity, diffusion coefficient, exchange current density and other parameters of the sample to be tested at different pressures and temperatures based on the received voltage / current data combined with pressure, temperature, cross-sectional data of the sample to be tested, etc.

[0038] The test device disclosed in this application has multiple test chambers and multiple corresponding liquid containing chambers. It can not only perform electrochemical tests on solid samples added to the test chamber, but also simulate liquid batteries. By adding electrolyte into the test chamber, electrochemical tests of electrode materials, electrolyte materials, etc. in liquid batteries can be realized, expanding the range of material testing. At the same time, multiple test chambers can be tested simultaneously, which can not only realize related tests of different materials and improve test efficiency; multiple parallel tests of the same material can also be performed simultaneously, improving test accuracy.

[0039] The above-mentioned testing device is exemplarily described below with reference to the accompanying drawings. Figure 1 , Figure 1 is an exemplary structural diagram of a test device according to some embodiments of the present application. Figure 1 As shown, where:

[0040] The pressure applying assembly may include a driving motor 3, a hydraulic unit electrically connected to the driving motor 3, and a pressure push piece transmission-connected to the hydraulic unit. The driving motor 3 may drive the hydraulic unit and thereby push the pressure push piece 20 to move. Figure 1As shown in , the hydraulic unit may include a hydraulic oil tank 1, a hydraulic pump 2, a flow meter 4, a three-position four-way reversing valve 5, a pressure gauge 6, a diverter valve 7 and a hydraulic cylinder 10 connected in sequence. Among them, the hydraulic cylinder 10 and the pressure push plate 20 can be connected to each other by force transmission components. For example, the hydraulic oil rod of the hydraulic cylinder 10 can be directly connected to the pressure push plate 20 by welding, riveting, threaded connection, etc., and the hydraulic oil rod can directly serve as the force transmission connecting rod. The hydraulic oil rod of the hydraulic cylinder 10 can also be connected to the pressure push plate 20 through an intermediate piece such as a straight rod, and the intermediate piece serves as the force transmission component. The drive motor 3 is connected to the hydraulic pump 2 in a transmission manner, and the hydraulic pump 2 receives the mechanical energy delivered by the drive motor 3 and converts it into hydraulic energy, which is then transmitted to the hydraulic cylinder 10 after subsequent components. The hydraulic cylinder 10 converts the hydraulic energy into mechanical energy so that the hydraulic oil rod performs linear reciprocating motion. The pressure push plate 20 can therefore move toward the sample to be tested contained in the test cavity, thereby pressing the pressure of the sample to be tested. In some embodiments, the drive motor 3 can be connected to a control unit (eg, Figure 1 The computing device 15 (e.g., an industrial computer, a laptop computer, a desktop computer, a tablet computer, an intelligent mobile device such as a smart phone, a controller such as a microcontroller, a programmable logic controller, etc.) can be used as a control unit. By sending an instruction to control the rotation speed of the motor to the drive motor 3, the extension speed of the hydraulic oil rod of the hydraulic oil cylinder 10 can be controlled when the oil circuit is connected, so as to control the pressure of the pressure push plate 20.

[0041] The three-position four-way reversing valve 5 can realize pressure supply, pressure maintenance and pressure release by controlling the working position state. For example, when the three-position four-way reversing valve 5 is in the left position, the entire oil circuit is connected, and the hydraulic pump 2 applies hydraulic energy to the hydraulic cylinder 10 driven by the drive motor 3. When the three-position four-way reversing valve 5 is in the middle position, the entire oil circuit is maintained, and the pressure applied by the pressure push plate 20 remains stable. When the three-position four-way reversing valve 5 is in the right position, the hydraulic oil rod of the hydraulic cylinder 10 retracts and the pressure is unloaded. In some embodiments, the three-position four-way reversing valve 5 can also be electrically connected to the computing device 15 to receive a control signal to change the working position state.

[0042] The diverter valve 7 is connected to the hydraulic cylinder 10 via a hydraulic oil pipe 8, which can be used for synchronization of the hydraulic cylinder 10 to ensure synchronous movement of the hydraulic oil rods of the multiple hydraulic cylinders 10 corresponding to the multiple test chambers.

[0043] The temperature control assembly may include a temperature box 9 and a heating unit 21, a heat preservation unit 31 and a cooling unit 26 that surround the test cavity 22 in sequence. Exemplarily, the heating unit 21 and the cooling unit 26 may be composed of heating elements such as electric heating wires, resistance wires, induction coils, etc. embedded in a heat-conducting layer made of a heat-conducting material such as a polymer, and cooling elements such as air-cooling pipes and liquid-cooling pipes. In another example, the heating unit 21 may be a layered product such as an electric heating film, and the cooling unit 26 may be an air-cooling pipe or a liquid-cooling pipe directly attached to the outer surface of the heating unit 21. In some embodiments, the heating unit 21 may include a resistance wire, and the temperature increase operation of the sample to be tested is completed by heating the resistance wire. Among them, the resistance wire may be segmented, for example, divided into two or more sections, each section is connected to a different external power supply to realize a separate power supply. In this way, different positions of the sample to be tested can be heated. The cooling unit 26 may include a liquid cooling pipe. The liquid cooling pipe is connected to an external cooling source, and liquid is introduced from the bottom and discharged from the top. The cooling rate of the sample to be tested is precisely controlled by controlling the flow rate / flow of the coolant. The computing device 15 can also control the heating unit 21 and the cooling unit 26. For example, the computing device 15 is electrically connected to the external power supply of the heating unit 21 and the external cooling source of the cooling unit 26. The heating unit 21 and the cooling unit 26 are controlled by controlling the power switch and power supply current of the external power supply and the opening and closing of the external cooling source and the flow / flow rate of the coolant (for example, by the degree of opening and closing of the valve). The heat preservation unit 31 may include a heat insulation layer made of heat insulation material. For example, glass wool, ceramic fiber, aluminum silicate fiber, polyurethane foam, polystyrene foam, polyethylene foam, vacuum insulation board, etc. can be used to prepare the heat preservation unit 31. The heat preservation unit 31 can be used to block the test cavity 22, the heating unit 21 from heat exchange with the outside, and maintain the internal temperature of the test cavity 22 stable. At the same time, a heat preservation unit 31 is also provided at the bottom of each test cavity 22 to block the heat exchange at the bottom of the test cavity 22.

[0044] The incubator 9 has a cavity 13 inside, which can be used to place a test cavity 22 (such as Figure 1 ). For example, a bracket 12 may be provided inside the incubator 9, such as a square bracket, a profile bracket, a square rack, a welding rack, or other racks capable of achieving any supporting function. The bracket 12 may include a top platform A, a base B, and a support rod connecting the top platform A and the base B. The bracket 12 may be provided inside the incubator 9 by welding, bonding, screw connection, etc., and a plurality of test chambers 22 may also be installed on the base B of the bracket 12 based on the same or similar connection method. Figure 1The two test chambers 22 shown in the figure can be placed on the base 25 through the grooves provided on the base 25, and the base 25 is fixedly connected to the base B through screw connection to complete the installation of the test chamber 22. At the same time, the hydraulic cylinder 10 in the pressure assembly can be installed on the top platform A. Similarly or similarly, the hydraulic cylinder 10 can first be installed on a mounting plate, and the mounting plate is then installed on the top platform A through the mounting flange 11, for example, by Figure 1 The top platform A has a through hole, and the hydraulic oil rod of the hydraulic oil cylinder 10 can pass through the through hole to connect with the pressure push piece 20.

[0045] The incubator 9, as part of the temperature control assembly, also achieves a heat preservation effect. Exemplarily, the incubator 9 can be made of a heat-insulating material such as a ceramic heat-insulating board to ensure the internal temperature and reduce heat loss. In addition, the incubator 9 can establish a gas passage with the outside, through which operations such as vacuuming can be achieved to convert the inside of the incubator 9 into a vacuum environment or to introduce a protective gas operation to provide an inert environment.

[0046] The sample holding assembly may include a plurality of test chambers 22 (eg Figure 1The invention relates to two test chambers 22 shown in the figure, and a first pole piece 16 disposed at the top of each test chamber 22 and a second pole piece 29 disposed at the bottom of the test chamber 22. The test chamber 22 can be used to accommodate a sample to be tested. In some embodiments, the test chamber 22 can be a hollow cylinder with an opening at one end, such as a cylinder, a cubic cylinder, etc. The pressure push piece 20 can have a size and shape that matches the opening so as to serve as a movable top of the test chamber 22. The bottom end of the test chamber 22 is a closed end of the hollow cylinder. The first pole piece 16 disposed at the top can be connected to the pressure push piece 20 and move with the movement of the pressure push piece 20. Exemplarily, the first pole piece 16 can be disposed on the side of the pressure push piece 20 facing the bottom end (or the sample to be tested) of the test chamber 22, or on the side relative to the surface of the sample to be tested. The second pole piece 29 disposed at the bottom can be fixedly placed at the bottom of the test chamber 22. When the sample to be tested is placed in the test chamber 22, the second pole piece 29 will be in direct contact with the sample to be tested. When the pressure push piece 20 presses against the sample to be tested, the first pole piece 16 will be in direct contact with the sample to be tested. In this way, the first pole piece 16, the sample to be tested and the second pole piece 29 will constitute a battery module to be tested. The feedback parameters (for example, voltage, current, etc.) generated after the battery module to be tested is powered on will participate in determining the electrochemical parameters of the sample to be tested, such as conductivity, tortuosity, diffusion coefficient, exchange current density, etc. The multiple test cavities 22 included in the sample holding assembly to be tested can test multiple samples at the same time, which improves the test efficiency and reduces the test errors caused by multiple separate tests. It should be noted that the first pole piece 16 and the second pole piece 29 are replaceable. For example, the pressure push piece 20 can withdraw from the test cavity 22, and the first pole piece 16 and the second pole piece 29 can be adaptively replaced for different electrochemical parameter test processes and different samples to be tested by manual replacement.

[0047] The sample holding assembly may further include a plurality of liquid containing chambers, and the plurality of liquid containing chambers may be arranged in one-to-one correspondence with the plurality of test chambers. The liquid containing chamber may be used to contain electrolyte. The electrolyte may be part of the electrolyte added to the test chamber 22 to form a liquid battery, and enters the liquid containing chamber due to the pressure change in the test chamber 22. Figure 2 An exemplary schematic diagram of a liquid containing chamber according to some embodiments of the present application is shown, as shown in FIG. Figure 2 As shown, the liquid containing chamber 34 can be attached to the outer peripheral wall of the test chamber 22. For example, the heating unit 21 reserves space near the bottom of the test chamber 22 and does not completely surround the test chamber 22. The reserved gap can be used as the liquid containing chamber 34. In order to prevent the test chamber 22 from having unstable temperature during the test process due to the reserved space, a heat insulating pad can be provided on one or more inner walls of the liquid containing chamber 34 to prevent heat exchange with the test chamber 22, the heating unit 21, etc., so as to keep the temperature of the test chamber 22 stable. Figure 2A heat insulation pad 36 is provided on the contact surface between the liquid containing cavity 34 and the heating unit 21 shown in FIG.

[0048] The liquid (e.g., electrolyte, which can be interchanged in the following content) in the liquid containing chamber 34 can enter and exit the test chamber 22. Exemplarily, a conducting hole is provided between the liquid containing chamber 34 and the corresponding test chamber 22, for example, a conducting hole 35 is provided on the peripheral wall of the test chamber 22. The sample holding assembly to be tested may also include a permeable film 33, which may be sealed on the conducting hole 35. The permeable film 33 may allow the electrolyte to flow between the liquid containing chamber 34 and the test chamber 22, thereby achieving liquid-phase communication between the liquid containing chamber 34 and the corresponding test chamber 22. At the same time, the permeable film 33 will block the sample to be tested (e.g., powder / particles) from passing through, thereby achieving solid phase barrier between the liquid containing chamber 34 and the corresponding test chamber 22. In this way, the free flow of the electrolyte in the two chambers can be guaranteed, while blocking the electrolyte from carrying powder / particles back to the liquid containing chamber 34 to contaminate all electrolytes.

[0049] The permeable film 33 for blocking the conducting hole between the liquid containing chamber 34 and the test chamber 22 can be arranged on the inner wall of the liquid containing chamber 34, such as Figure 2As shown in ; or, the permeable film 33 can be arranged on the inner wall of the upper test cavity 22; or, the permeable film 33 can be arranged on the inner wall of the liquid containing cavity 34 or the inner wall of the test cavity 22. Alternatively, the permeable film 33 can be directly arranged inside the through hole 35. The permeable film 33 can be a microporous membrane, and polymer materials such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyurethane (TPU), polypropylene (PP) and / or inorganic materials such as ceramics, glass, metal elements, metal alloys, etc. can be used to prepare the permeable film 33. Due to the liquid phase circulation effect of the permeable film 33, the electrolyte added to the test cavity 22 during the test process can enter and exit the liquid containing cavity 34, thereby maintaining the appropriate content of the electrolyte in the test cavity 22. Exemplarily, when the test cavity 22 is loaded with the sample to be tested and the electrolyte, it forms a liquid battery with other components (for example, the first pole piece 16 and the second pole piece 29, etc.). During the entire test process of the liquid battery, the pressure push piece 20 can have different states, including a pressure state and a retracted state. When the pressure push piece 20 is in a pressure state, it can apply pressure to the sample to be tested. At this time, the gap between the powder / particles is reduced under the force condition, or the shape of the overall battery module to be tested (for example, the above-mentioned liquid battery) changes, and the electrolyte in the test cavity 22 can enter the liquid containing cavity 34 through the permeable film for accommodation. When the pressure push piece 20 is in a retracted state, that is, the hydraulic cylinder 10 drives the pressure push piece 20 to move in the opposite direction away from the sample to be tested, or it is called moving in the opposite direction of the force applied to the sample to be tested. At this time, the gap between the powder / particles increases and more electrolyte can be accommodated. The liquid in the liquid containing cavity 34 will enter the test cavity 22 through the permeable membrane. Based on this, when the pressure push piece 20 applies different pressures to the sample to be tested, the pressure in the test cavity 22 will also be different. The electrolyte can circulate back and forth in the test chamber 22 and the liquid containing chamber 34 based on different pressures, thereby ensuring that the content of the electrolyte in the test chamber 22 is at an appropriate level during the test process.

[0050] Of course, the liquid containing chamber 34 may be arranged in other ways. One example is that the liquid containing chamber may be arranged on the bracket 12 like the test chamber 22. The liquid containing chamber is in liquid communication with the test chamber 22 through a conducting pipe that passes through the test chamber 22 and the temperature regulating component.

[0051] The test assembly can be electrically connected to the first pole piece 16 and the second pole piece 29 to apply voltage or current to the battery module to be tested. Exemplarily, the test assembly may include an electrochemical workstation 14. The electrochemical workstation 14 can be electrically connected to a control unit (e.g., a computing device 15) to receive a control signal to perform a corresponding electrochemical test on the battery module to be tested. For example, a set voltage or current is applied to the first pole piece 16 and the second pole piece 29 through a wire, and the voltage V, current I, time t and other data fed back are obtained. At the same time, the electrochemical workstation 14 can also transmit the above feedback parameters (e.g., voltage V, current I, time t, etc.) to the computing device 15. In some examples, the test assembly can perform electrochemical tests on multiple samples to be tested at the same time. For example, multiple test chambers 22 are used to place the same or different samples to be tested, and each test chamber 22 performs the same or different electrochemical tests. This improves the test efficiency and saves test time.

[0052] In order to prevent short circuit or safety hazards caused by leakage during the power-on process, an insulating gasket 17 (or referred to as the first insulating member) can be provided between the first pole piece 16 and the pressure push piece 20, and an insulating gasket 17 (or referred to as the second insulating member) can also be provided between the second pole piece 29 and the bottom end of the test cavity 22. For example, rubber gaskets, PET (polyethylene terephthalate) gaskets, PC (polycarbonate) gaskets, etc. The size of the insulating gasket 17 can be the same as or larger than the first pole piece 16 or the second pole piece 29 to achieve the purpose of complete coverage. Alternatively, the first pole piece 16 or the second pole piece 29 can be embedded in the insulating gasket 17 and expose the surface layer to form a component. These are all non-restrictive.

[0053] Other data required for determining the electrochemical parameters of the sample to be tested, such as pressure, temperature, deformation degree of the sample to be tested, etc., can be acquired by the data monitoring component. The data monitoring component can include a pressure sensor for detecting the pressure applied by the pressure push sheet 20 to the sample to be tested. Figure 1 An exemplary solution is shown, in which the pressure sensor 18 is arranged between the pressure push piece 20 and the insulating gasket 17 through the mounting seat 19. For example, the pressure sensor 18 is embedded in the mounting seat 19 and the sensing surface is exposed, and is arranged between the mounting seat 19 and the insulating gasket 17. The pressure push piece 20 will be located on the other side of the insulating gasket 17 opposite to the side in contact with the first pole piece 16. Any pressure sensor suitable for a hydraulic system can be used as the pressure sensor 18. Another example can be that the pressure sensor 18 can be a patch pressure sensor, a flexible pressure sensor or a thin film pressure sensor, without the mounting seat 19, and the position fixation and pressure measurement are completed by the pressure fitting between the pressure push piece 20 and the insulating gasket 17.

[0054] The data monitoring assembly may also include a temperature sensor / temperature probe for detecting the temperature of the sample to be tested placed in the test cavity 22. In some embodiments, the data monitoring assembly may include a non-fixed temperature sensor 32 that moves with the pressure push piece 20 and a fixed temperature sensor 24 that is arranged at a predetermined position on the inner wall of the test cavity 22. The non-fixed temperature sensor 32 may include a patch-type temperature sensor, which may be directly attached to the surface of the sample to be tested, and move in position while the pressure push piece 20 moves against the sample to be tested and deforms. The non-fixed temperature sensor 32 may also be a mobile temperature probe, which may be inserted into the interior of the sample to be tested, and move in position while the pressure push piece 20 moves against the sample to be tested and deforms. The non-fixed temperature sensor 32 may also be connected to the pressure push piece 20 through other intermediate components. For example, an insulating sensor arrangement sheet. The insulating sensor arrangement sheet is C-shaped, one end of which may be connected to the pressure push piece 20, and one end of which is used to install the non-fixed temperature sensor 32. The non-fixed temperature sensor 32 may be attached to the inner wall of the test cavity 22. After the setting is completed, when the pressure push piece 20 moves, it will drive the insulating sensor arrangement piece to move, thereby driving the non-fixed temperature sensor 32 to move along the inner wall of the test cavity 22. The fixed temperature sensor 24 can be fixedly installed on the inner wall of the test cavity 22. For example, Figure 1 As shown, the fixed temperature sensor 24 can be a temperature probe, and a through hole is provided in the part near the bottom of the test cavity 22, and the through hole passes through the heating unit 21, the cooling unit 31 and the insulation unit 26 covering the outer wall of the test cavity 22. The temperature probe extends into the interior of the test cavity 22 through the through hole and protrudes from the inner wall of the test cavity 22. A sealing ring 28 is provided in the through hole to prevent temperature leakage. In another exemplary embodiment, the fixed temperature sensor 24 can be directly fixedly installed on the inner wall of the test cavity 22 to achieve temperature measurement at a fixed position.

[0055] The data monitoring component may also include a displacement sensor 30 for detecting the degree of deformation of the sample to be tested placed in the test cavity 22, or detecting the displacement of the pressure push piece 20. In some embodiments, the displacement sensor 30 may include an optical displacement sensor, which is disposed on the bottom surface of the top platform A of the bracket 12 (for example, the side facing the base B). Exemplarily, the displacement sensor 30 may be a laser ranging sensor, which is disposed within the range of the positive projection of the pressure push piece 20 on the bottom surface of the top platform A of the bracket 12. In this way, the displacement sensor 30 can accurately obtain the displacement of the pressure push piece 20, thereby obtaining the degree of deformation of the sample to be tested, for example, height change.

[0056] The data monitoring component may further include a data collector 27 . The data collector 27 may be electrically connected to the above-mentioned various sensors, and receive the electrical signals sent by the sensors and convert them into digital signals, which are then transmitted to the computing device 15 .

[0057] The computing device 15 can be electrically connected to the above-mentioned pressure component, data monitoring component, temperature adjustment component, test component, etc. to perform signal transmission and parameter calculation. Exemplarily, the computing device 15 can be electrically connected to the drive motor 3 and the three-position four-way reversing valve 5 in the pressure component to control the rotation of the drive motor 3 and control the working position state of the three-position four-way reversing valve 5 to achieve pressure application, pressure maintenance and pressure unloading operations. The computing device 15 can also be electrically connected to the heating unit 21 and the cooling unit 31 in the temperature adjustment component to control the working state and power of the heating unit 21 and the cooling unit 31. The computing device 15 can also be electrically connected to the data acquisition device 27 in the data monitoring component to receive real-time temperature, pressure, and displacement data to enter the operation of the pressure component and the temperature adjustment component based on these data to achieve precise pressure control and temperature control. At the same time, precise pressure control can enable different samples to be tested to achieve different densities or porosities, so that the electrochemical parameters of the samples to be tested under different densities / porosities can be determined. An exemplary pressure / temperature control process may be that the computing device 15 controls the three-position four-way reversing valve 5 to be in the left position and controls the driving motor 3 to rotate, driving the hydraulic pump 2 to apply power to the hydraulic cylinder 10. When the pressure monitored by the pressure sensor 18 is equal to the preset pressure or the sample to be tested reaches the specified porosity, the computing device 15 controls the three-position four-way reversing valve 5 to be in the middle position so that the pressure or porosity is maintained at a stable value. When the entire test is completed, the computing device 15 controls the three-position four-way reversing valve 5 to be in the right position so that the hydraulic oil rod of the hydraulic cylinder 10 retracts and unloads the pressure. At the same time, when the pressure loading is completed, the computing device 15 can control the temperature control component to cool or heat the sample to be tested. When the temperature difference between the temperature at the monitoring point of the non-fixed temperature sensor 32 and the temperature monitored at the monitoring point of the fixed temperature sensor 24 is less than 0.5°C, the computing device 15 can control the temperature control component to stop working.

[0058] The porosity involved in the above description can be determined based on the following exemplary process:

[0059] The test density of the sample to be tested can be first determined based on the following formula 1:

[0060]

[0061] Wherein, m represents the total mass of the sample to be tested, in g; H represents the height of the sample to be tested, in cm; S represents the cross-sectional area of ​​the test cavity 22, i.e., the cross-sectional area of ​​the sample to be tested, in cm 2 ;

[0062] The porosity ε can be determined based on the following formula 2:

[0063]

[0064] Among them, ρ T Indicates the true density of the sample to be tested.

[0065] The test device disclosed in the present application has multiple test chambers to perform tests under the same conditions at the same time, eliminating the influence of environmental variables and reducing test errors. At the same time, the test device can test electrochemical parameters related to materials at different temperatures and pressures, with high pressure control accuracy and more uniform and rapid heating. Moreover, the electrochemical parameters related to materials under different densities / porosities can be tested through precise pressure control.

[0066] The present application also discloses a method for using the above test device, which may include the following exemplary steps.

[0067] Step 1: The computing device 15 generates corresponding test steps and corresponding electrode sheet (e.g., the first electrode sheet 16 and the second electrode sheet 29) materials according to the relevant parameters of the test material to be tested (i.e., the aforementioned sample to be tested) specified by the external instruction. At the same time, the relevant parameters involved in the test process, such as pressure, temperature, etc., can be adjusted based on external data.

[0068] Step 2: The operator replaces the electrode sheet according to the recommendation of the computing device 15 and completes the overall installation of the test device and starts it.

[0069] Step three, the computing device 15 controls the driving motor 3 to drive the hydraulic pump 2 and controls the three-position four-way electronic reversing valve 5 to control the hydraulic cylinder 10 to apply pressure to the tested material, and the pressure sensor 18 monitors the pressure applied by the hydraulic cylinder 10 to the tested material; when the pressure monitored by the pressure sensor 18 reaches the set pressure value or the porosity reaches the specified value, the computing device 15 controls the three-position four-way electronic reversing valve 5 to be in the middle position.

[0070] Step 4: The computing device 15 controls the heating unit 21 to heat the material under test, or controls the cooling unit 31 to cool the material under test. The temperature sensor (including the fixed temperature sensor 24 and the non-fixed temperature sensor 32) monitors the temperature inside the material under test. When the temperature inside the material under test reaches the set temperature value, the computing device 15 controls the heating unit 21 or the cooling unit 31 to adjust the temperature of the material under test until the temperature stabilizes at the set temperature value.

[0071] Step 5: The computing device 15 sends the automatically generated test steps to the electrochemical workstation 14, and the electrochemical workstation 14 completes the test according to the test steps.

[0072] Step 6: The computing device 15 completes the test data call (for example, obtains relevant test data from the electrochemical workstation 14 and the data collector 27), and completes the parameter calculation of the tested material at the specified pressure and specified temperature according to the built-in data processing method and parameter processing method.

[0073] Step 7: Repeat steps 4 to 6 until all tests at the specified temperature are completed.

[0074] Step 8: Repeat steps 3 to 7 until all tests under the specified pressure are completed.

[0075] Step 9: The computing device 15 controls the driving motor 3 to drive the hydraulic pump 2 and controls the three-position four-way electronic reversing valve 5 to control the hydraulic cylinder 10 to unload the pressure applied to the tested material until the pressure push piece exits the test cavity 22. The test process ends after the test cavity 22 is cleared.

[0076] For different electrochemical parameters, the calculation device 15 can automatically calculate according to the following corresponding processes.

[0077] For the conductivity test, a platinum metal sheet can be used as the first electrode 16, and a lithium metal sheet can be used as the second electrode 29. When the test device is installed, the computing device 15 can control the pressure component to apply a specified pressure or porosity to the material under test, and control the temperature adjustment component to adjust the temperature of the material under test to a specified temperature T. The temperature T of the point that needs to be monitored by the non-fixed temperature sensor is f and the temperature T monitored by the fixed temperature sensor monitoring point g The temperature difference is less than 0.5° C. Subsequently, the electrochemical workstation 14 completes the test of the resistance R of the material under test, and the calculation device 15 calculates the material conductivity σ based on the received data according to Formula 3:

[0078]

[0079] Where H represents the height of the material to be tested, in cm; A represents the cross-sectional area of ​​the test cavity 22, i.e., the cross-sectional area of ​​the material to be tested, in cm 2 ; R represents the ohmic internal resistance of the material being measured, in Ω. The height H of the material being measured can be determined based on the following formula 4:

[0080] H=H0-L-2×H j -H d -2×H jy -H t (4)

[0081] Wherein H0 represents the installation height of the displacement sensor 30, in cm; L represents the measurement distance (i.e., the measured displacement) of the displacement sensor 30, in cm; H jH is the thickness of the first pole piece 16, in cm; d Indicates the installation thickness of the mounting seat 19, in cm; H jy Indicates the thickness of the insulating gasket 17, in cm; H t represents the thickness of the pressure push sheet 20, in cm. If it is the first time to apply pressure, the height H of the test material can be directly determined according to the displacement measured by the displacement sensor 30, for example, by subtracting the displacement measured by the displacement sensor 30 from the original height of the tested material before the pressure is applied. After a test is completed, the computing device 15 can control and adjust the pressure and temperature until the test under all test conditions is completed.

[0082] For the tortuosity test, a platinum metal sheet can be used as the first electrode sheet 16, and a lithium metal sheet can be used as the second electrode sheet 29 to construct a symmetrical electrode. When the test device is installed, the computing device 15 can control the pressure component to apply a specified pressure or porosity to the material under test, and control the temperature adjustment component to adjust the temperature of the material under test to a specified temperature T. The temperature T of the point where the non-fixed temperature sensor is required to monitor the temperature f and the temperature T monitored by the fixed temperature sensor monitoring point g The temperature difference is less than 0.5°C. Then, the electrochemical workstation 14 completes the diffusion resistance R d In the test, the computing device 15 calculates the material tortuosity τ according to the received data based on Formula 5:

[0083]

[0084] After a test is completed, the computing device 15 may control and adjust the pressure and temperature until the test under all test conditions is completed.

[0085] For the diffusion coefficient test, a platinum metal sheet can be used as the first electrode 16, and a lithium metal sheet can be used as the second electrode 29. When the test device is installed, the computing device 15 can control the pressure component to apply a specified pressure or porosity to the material under test, and control the temperature adjustment component to adjust the temperature of the material under test to a specified temperature T. The temperature T of the point that needs to be monitored by the non-fixed temperature sensor f and the temperature T monitored by the fixed temperature sensor monitoring point g The temperature difference is less than 0.5°C. Then, the electrochemical workstation 14 completes the diffusion coefficient D based on the test process transmitted by the computing device 15. sTest: 1. Use the specified rate to charge to the cut-off voltage V1 with the constant current and constant voltage charging strategy, and let it stand for a period of time; 2. Use the specified rate to discharge with the constant current discharge strategy for a specified time, and let it stand for 0.5h; 3. Cycle step 2 until the discharge cut-off voltage V2 is reached; 4. Let it stand for a period of time; 5. Use the specified rate to discharge with the constant current charging strategy for a specified time, and let it stand for 0.5h; 6. Cycle step 2 until the discharge cut-off voltage V1 is reached; 7. Calculate the diffusion coefficient D based on the following formula 6 s :

[0086]

[0087] Among them, D s represents the solid phase diffusion coefficient, ∈ represents the current pulse time, n M Indicates the number of moles of the material being tested, V M represents the molar volume of the material being tested, A represents the contact area between the electrode and the electrolyte, ΔE s represents the steady-state voltage change, ΔE t After a test is completed, the computing device 15 can control and adjust the pressure and temperature until the test under all test conditions is completed.

[0088] For the exchange current density test, a platinum metal sheet can be used as the first pole piece 16, and a lithium metal sheet can be used as the second pole piece 29. When the test device is installed, the computing device 15 can control the pressure component to apply a specified pressure or porosity to the material under test, and control the temperature adjustment component to adjust the temperature of the material under test to a specified temperature T. The temperature T of the point that needs to be monitored by the non-fixed temperature sensor f and the temperature T monitored by the fixed temperature sensor monitoring point g The temperature difference is less than 0.5°C. Subsequently, the electrochemical workstation 14 completes the test of the exchange current density i0 based on the test process transmitted by the computing device 15: 1. Charge to the cut-off voltage V1 using a constant current and constant voltage charging strategy at a specified rate and let it stand for a period of time; 2. Use the electrochemical workstation to test the electrochemical impedance spectrum; 3. Figure 3 The circuit shown relates the different processes occurring in the battery; 4. Calculate the exchange current density i0 according to the following equation 7:

[0089]

[0090] Among them, R2 represents the charge transfer internal resistance, R Frepresents the universal gas constant, T represents the temperature, F represents the Faraday constant, A represents the contact area between the electrode and the electrolyte, and S represents the effective surface area of ​​the electrochemical reaction; 5. Adjust the SOC of the button battery tested in step 2 to 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 0% in sequence; let it stand for 1 hour; cycle steps 2-3 to complete a test. After the test is completed, the computing device 15 can control and adjust the pressure and temperature until the test under all test conditions is completed.

[0091] The following is a further description of the test process of the test device disclosed in the present application in conjunction with the embodiments. It should be noted that the following embodiments are only used to illustrate the present application and are not used to limit the scope of protection claimed in the present application.

[0092] Example 1 - Conductivity Test

[0093] The radius of the test cavity 22 in Example 1 is equal to 5 mm.

[0094] 1)1 Take a certain amount of sulfide solid electrolyte lithium phosphorus sulfur chlorine (LPSC) and test its weight, then put it into the test cavity 22, the platinum metal sheet is used as the first pole piece 16, and the lithium metal sheet is used as the second pole piece 29. After the pressure sensor 18 is installed on the mounting seat 19, the insulating gasket 17 and the mounting seat 19 are sequentially installed into the test cavity 22. The test cavity 22 is placed in the groove of the base 25.

[0095] 2) Start the test device and select the test parameter as conductivity test on the computing device 15. Set the pressure to 25MPa, 40MPa, 55MPa, 60MPa, 75MPa, 80MPa, 100MPa, 115MPa, 130MPa, 145MPa and 160MPa, and the temperature to 25°C.

[0096] 3) The computing device 15 controls the driving motor 3 so that the hydraulic oil rod pushes the pressure push piece 20 at a speed of 0.1 mm / s. When the pressure monitored by the pressure sensor 18 has a difference of 10% from the preset value, the speed of the pressure push piece 20 is reduced to 0.05 mm / s until the pressure stabilizes at 25 MPa. Let stand for 10 minutes.

[0097] 4) After the temperature of the thermostat is stabilized at 25°C by the computing device 15, the computing device controls the heating unit 21 and the cooling unit 31 until the temperature T of the monitoring point of the non-fixed temperature sensor 32 reaches 25°C. f The temperature T monitored by the fixed temperature sensor 24 monitoring points g The temperature difference is less than 0.5℃, and T f and T g If the error from the set temperature value of 25°C is less than 0.5°C, the heating or cooling of the object being measured will be stopped.

[0098] 5) The electrochemical workstation 14 tests the electrochemical impedance spectrum of the solid electrolyte to obtain the resistance R of the solid electrolyte ions.

[0099] 6) Calculate conductivity

[0100] 7) Repeat steps 3)-6) until all tests under pressure or porosity and temperature conditions are completed.

[0101] The test results are as follows Figure 4 shown.

[0102] Example 2 - Tortuosity Test

[0103] 1) A certain amount of graphite particles with a particle radius of 13.8 microns mixed with a conductive agent and a composite electrolyte membrane with a porosity of 0.42 are placed in the test cavity 22 in the order of graphite-membrane-graphite, and LiPF6 electrolyte is injected into the test cavity 22. A platinum metal sheet is used as the first pole piece 16, and a lithium metal sheet is used as the second pole piece 29. After the pressure sensor 18 is installed on the mounting seat 19, the insulating gasket 17 and the mounting seat 19 are installed in the test cavity 22 in sequence. The test cavity 22 is placed in the groove of the base 25.

[0104] 2) Start the test device and select the test parameter as tortuosity test on the computing device 15. Set the pressure to 25 MPa, 40 MPa, 55 MPa, 60 MPa, 75 MPa, 80 MPa, 100 MPa, 115 MPa, 130 MPa, 145 MPa and 160 MPa, and the temperature to 25°C.

[0105] 3) The computing device 15 controls the driving motor 3 so that the hydraulic oil rod pushes the pressure push piece 20 at a speed of 0.1 mm / s. When the pressure monitored by the pressure sensor 18 has a difference of 10% from the preset value, the speed of the pressure push piece 20 is reduced to 0.05 mm / s until the pressure stabilizes at 25 MPa. Let stand for 10 minutes.

[0106] 4) After the temperature of the thermostat is stabilized at 25°C by the computing device 15, the computing device controls the heating unit 21 and the cooling unit 31 until the temperature T of the monitoring point of the non-fixed temperature sensor 32 reaches 25°C. f The temperature T monitored by the fixed temperature sensor 24 monitoring points g The temperature difference is less than 0.5℃, and T f and T g If the error from the set temperature value of 25°C is less than 0.5°C, the heating or cooling of the object being measured will be stopped.

[0107] 5) The electrochemical workstation 14 tests the electrochemical impedance spectrum of the solid electrolyte and obtains the diffusion impedance R of the graphite material d .

[0108] 6) Calculate tortuosity

[0109] 7) Repeat steps 3)-6) until all tests under pressure or porosity and temperature conditions are completed.

[0110] The tortuosity test results at different pressures at 25°C are as follows: Figure 5 shown.

[0111] Example 3 - Diffusion coefficient test

[0112] 1) A certain amount of graphite particles with a particle radius of 13.8 microns mixed with a conductive agent and a composite electrolyte membrane with a porosity of 0.42 are placed in the test cavity 22 in the order of graphite-membrane-graphite, and LiPF6 electrolyte is injected into the test cavity 22. A platinum metal sheet is used as the first pole piece 16, and a lithium metal sheet is used as the second pole piece 29. After the pressure sensor 18 is installed on the mounting seat 19, the insulating gasket 17 and the mounting seat 19 are installed in the test cavity 22 in sequence. The test cavity 22 is placed in the groove of the base 25.

[0113] 2) Start the test device and select the test parameter as tortuosity test on the computing device 15. Set the pressure to 25 MPa, 40 MPa, 55 MPa, 60 MPa, 75 MPa, 80 MPa, 100 MPa, 115 MPa, 130 MPa, 145 MPa and 160 MPa, and the temperature to 25°C.

[0114] 3) The computing device 15 controls the driving motor 3 so that the hydraulic oil rod pushes the pressure push piece 20 at a speed of 0.1 mm / s. When the pressure monitored by the pressure sensor 18 has a difference of 10% from the preset value, the speed of the pressure push piece 20 is reduced to 0.05 mm / s until the pressure stabilizes at 25 MPa. Let stand for 10 minutes.

[0115] 4) After the temperature of the thermostat is stabilized at 25°C by the computing device 15, the computing device controls the heating unit 21 and the cooling unit 31 until the temperature T of the monitoring point of the non-fixed temperature sensor 32 reaches 25°C. f The temperature T monitored by the fixed temperature sensor 24 monitoring points g The temperature difference is less than 0.5℃, and T f and T g If the error from the set temperature value of 25°C is less than 0.5°C, the heating or cooling of the object being measured will be stopped.

[0116] 5) The electrochemical workstation 14 completes the diffusion coefficient D of the material being testeds Test: 1. Use 0.1C current to charge with constant current and constant voltage charging strategy to a cut-off voltage of 1.28V, and let it stand for a while; 2. Use 0.05C current to discharge with constant current strategy for 12min, and let it stand for 0.5h; 3. Cycle step 2 until the discharge cut-off voltage reaches 0.09V; 4. Let it stand for a while; 5. Use 0.1C current and constant voltage charging strategy to charge for a specified time, and let it stand for 0.5h; 6. Cycle step 5 until the charge cut-off voltage reaches 0.65V; 7. Calculate the diffusion coefficient:

[0117] The diffusion coefficient at 25°C and 55 MPa is Figure 6 shown.

[0118] Example 4 - Exchange current density test

[0119] 1) A certain amount of graphite particles with a particle radius of 13.8 microns mixed with a conductive agent and a composite electrolyte membrane with a porosity of 0.42 are placed in the test cavity 22 in the order of graphite-membrane-graphite, and LiPF6 electrolyte is injected into the test cavity 22. A platinum metal sheet is used as the first pole piece 16, and a lithium metal sheet is used as the second pole piece 29. After the pressure sensor 18 is installed on the mounting seat 19, the insulating gasket 17 and the mounting seat 19 are installed in the test cavity 22 in sequence. The test cavity 22 is placed in the groove of the base 25.

[0120] 2) Start the test device and select the test parameter as tortuosity test on the computing device 15. Set the pressure to 25 MPa, 40 MPa, 55 MPa, 60 MPa, 75 MPa, 80 MPa, 100 MPa, 115 MPa, 130 MPa, 145 MPa and 160 MPa, and the temperature to 25°C.

[0121] 3) The computing device 15 controls the driving motor 3 so that the hydraulic oil rod pushes the pressure push piece 20 at a speed of 0.1 mm / s. When the pressure monitored by the pressure sensor 18 has a difference of 10% from the preset value, the speed of the pressure push piece 20 is reduced to 0.05 mm / s until the pressure stabilizes at 25 MPa. Let stand for 10 minutes.

[0122] 4) After the temperature of the thermostat is stabilized at 25°C by the computing device 15, the computing device controls the heating unit 21 and the cooling unit 31 until the temperature T of the monitoring point of the non-fixed temperature sensor 32 reaches 25°C. f The temperature T monitored by the fixed temperature sensor 24 monitoring points g The temperature difference is less than 0.5℃, and T f and T g If the error from the set temperature value of 25°C is less than 0.5°C, the heating or cooling of the object being measured will be stopped.

[0123] 5) The electrochemical workstation 14 completes the test of the exchange current density i0 of the tested material: 1. Use a current of 0.1C to charge to a cut-off voltage of 0.65V using a constant current and constant voltage charging strategy, and let it stand for a period of time; 2. Use the electrochemical workstation to test the electrochemical impedance spectrum; 3. The measured electrochemical impedance spectrum is measured according to Figure 3 The circuit shown relates the different processes occurring within the battery, where L1 is 552nH, R1 is 705μΩ, R2 is 147μΩ, and R3 is 157μΩ. Calculate the exchange current density; 4. Adjust the SOC of the battery formed by the test material in step 2 to 95%, 90%, 80%, 70%, 50%, 30%, 20%, 10%, and 5% in sequence; let it stand for 1 hour; cycle steps 2-3, and measure the exchange current density at different SOCs as follows: Figure 7 shown.

[0124] The present application has described the basic concepts. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0125] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or multiple times in different positions in the present application does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0126] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this application, multiple features are sometimes combined into one embodiment or its description. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0127] Finally, it should be understood that the embodiments described in this application are only used to illustrate the principles of the embodiments of the present application. Other variations may also fall within the scope of the present application. Therefore, as an example and not a limitation, the alternative configurations of the embodiments of the present application may be considered to be consistent with the teachings of the present application. Accordingly, the embodiments of the present application are not limited to the embodiments explicitly introduced and described in the present application.

Claims

1. A device for testing electrochemical parameters, characterized in that: The testing device comprises: a pressure-applying component, a test sample holding component, a testing component and a control unit; wherein, The test sample holding component comprises a plurality of test cavities, each of which can accommodate a corresponding test sample; The pressure-applying assembly includes a plurality of pressure push pieces corresponding to the test cavities one by one, and the pressure push pieces can press the samples to be tested in the corresponding test cavities and apply pressure to the samples to be tested; The test assembly can be electrically connected to the sample to be tested through the pressure push piece, and can perform an electrochemical test on at least one of the samples to be tested; The control unit is electrically connected to the pressure-applying component and the testing component. The control unit can drive the pressure-applying component and can control the testing component to perform an electrochemical test on the at least one sample to be tested.

2. The testing device according to claim 1, characterized in that: The pressure applying component also includes: a drive motor electrically connected to the control unit; and A hydraulic unit, transmission-connected to the drive motor and transmission-connected to the pressure-applying assembly; Wherein, the driving motor drives the hydraulic unit, and pushes the pressure push plate to move through the hydraulic unit.

3. The testing device according to claim 1, characterized in that: The sample holding component further comprises: a plurality of liquid containing cavities, which are arranged corresponding to the plurality of test cavities one by one; wherein the liquid containing cavities are in liquid communication with the corresponding test cavities and are separated by solid phase.

4. The testing device according to claim 3, characterized in that: The sample holding assembly to be tested also includes: a permeable film; a conducting hole is arranged between the liquid containing cavity and the corresponding test cavity, and the permeable film is sealed on the conducting hole; wherein the liquid containing cavity and the corresponding test cavity are in liquid communication through the permeable film.

5. The testing device according to claim 4, characterized in that: The permeable film is arranged on the inner wall of the liquid containing cavity and seals the conducting hole; And / or, the permeable film is arranged on the inner wall of the test cavity and seals the conducting hole; Preferably, a heat insulating pad is provided on one or more inner walls of the liquid containing cavity.

6. The testing device according to claim 4, characterized in that: The pressure push piece includes a pressure-applying state and a retracted state. When in the pressure-applying state, the pressure push piece can apply pressure to the sample to be tested, and the liquid in the test cavity can enter the liquid containing cavity through the permeable membrane; when in the retracted state, the pressure push piece can be retracted in a direction opposite to the force-applying direction, and the liquid in the liquid containing cavity can enter the test cavity through the permeable membrane.

7. The testing device according to claims 1-6, characterized in that: A first pole piece is arranged on the surface of the pressure push piece opposite to the sample to be tested, a second pole piece is arranged at the bottom of the test cavity, and the sample to be tested is connected between the first pole piece and the second pole piece to form a battery module to be tested; Preferably, the test component includes an electrochemical workstation, which is electrically connected to the control unit and electrically connected to the first pole piece and the second pole piece, and the electrochemical workstation performs corresponding electrochemical tests on the battery module to be tested according to the control signal of the control unit.

8. The testing device according to claim 1, characterized in that: It also includes a temperature control component, which is electrically connected to the control unit, and the control unit can control the temperature control component to heat or cool down; the temperature control component includes an incubator, a heating unit, a cooling unit and a heat preservation unit; the sample holding component to be tested is arranged in the incubator, and the outer walls of the multiple test cavities are sequentially coated with the heating unit, the heat preservation unit and the cooling unit from the inside to the outside, and the heat preservation unit is provided at the bottom of the multiple test cavities.

9. The testing device according to claim 1, characterized in that: It also includes a data monitoring component, which is electrically connected to the control unit, and the control unit can obtain monitoring data of the data monitoring component; The data monitoring component includes a fixed temperature sensor and a non-fixed temperature sensor; the non-fixed temperature sensor is fixedly connected to the pressure push piece and can move along the inner wall of the test cavity with the pressure push piece; the fixed temperature sensor is fixed on the inner wall of the test cavity and is arranged close to the bottom of the test cavity; Preferably, the data monitoring component also includes a pressure sensor, the pressure-applying component also includes a mounting seat and an insulating gasket, the pressure sensor is arranged between the mounting seat and the insulating gasket, and the pressure push plate is arranged on the other side of the insulating gasket.

10. The testing device according to claim 1, characterized in that: The control unit includes one or more of a CPU, an MCU and a PLC; Preferably, the electrochemical parameters include one or more of conductivity, tortuosity, diffusion coefficient and exchange current density; Preferably, the test component is capable of performing electrochemical tests on a plurality of the samples to be tested, wherein the plurality of the samples to be tested are the same or different, and the plurality of the electrochemical tests are the same or different.

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