In-situ electrochemical common combined test device and test method based on double-window detection

Abstract

The invention discloses an in-situ electrochemical common combined test device and method based on double-window detection, the device comprises an upper cover body and a lower cover body which is hermetically connected below the upper cover body, a battery is installed between the upper cover body and the lower cover body, two wiring assemblies are hermetically installed below the lower cover body, and the two wiring assemblies are in contact with two poles of the battery. The battery is connected with an external circuit; a window A for X-ray transmission is installed in the center of the upper cover body, a window B for laser transmission is installed in the center of the lower cover body, and a lifting assembly for height adjustment is installed below the lower cover body. According to the invention, the same-batch test characterization of the positive electrode material and the negative electrode material of the total battery can be realized, the problem that the existing test device can only test single polarity is solved, and positive electrode in-situ XRD measurement and CT diffractometer measurement are realized during charging and discharging of the battery; and a powerful and reliable technical platform and data support are provided for revealing a complex failure mechanism of the battery in situ, analyzing a reaction mechanism and guiding the material design of the long-life battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to an in-situ electrochemical common-use testing device based on double-window detection and a testing method. BACKGROUND

[0002] With the rapid development of electrochemical energy storage technology, the research of new battery systems such as lithium ion batteries and sodium ion batteries has deepened from macroscopic performance evaluation to microscopic mechanism analysis. In order to dynamically capture the complex structural evolution, interface reaction and failure mechanism of batteries during operation, the combination of multiple in-situ / working condition characterization technologies has become a hot spot and inevitable trend in frontier research. Raman spectroscopy, X-ray diffraction and computed tomography (CT) can provide dynamic information of battery materials under real working conditions from different scales such as molecular vibration, crystal structure and three-dimensional morphology, which provides indispensable data support for building accurate battery reaction models and designing next-generation high-performance battery materials.

[0003] However, despite the urgent demand, current soft-pack batteries still face a series of severe technical bottlenecks, which seriously restrict their scientific research output and practical application efficiency. These bottlenecks mainly manifest in the following aspects: ① single function: traditional in-situ testing devices usually only support a single technology (such as Raman or XRD), making it difficult to realize the same batch testing and characterization of positive and negative materials of the whole battery. ② poor practicability: the current device is difficult to adapt to different brands and models of commercial spectrometers or diffractometers, limiting its versatility. ③ insufficient compatibility: the structural design of the existing device does not fully consider the combined use of multiple characterization technologies, such as the spatial conflict between Raman light path and X-ray path, the contradiction between battery sealing and light / transmission requirements, etc., leading to signal interference or resolution decline, making it difficult to compatible with various technical testing scenarios and common-use data acquisition. ④ complex device: the cumbersome assembly process not only reduces the experimental efficiency, but also introduces many uncertainties (such as uneven sealing pressure, electrode displacement), affecting the reproducibility and reliability of the data. ⑤ high cost: based on the physical properties of laser and X-ray, it is necessary to select a mold window material that has both mechanical strength and laser / X-ray transmittance. Precise machining and customized design result in high cost of a single device, making it difficult to popularize and promote in laboratories. SUMMARY

[0004] The application discloses a double-window detection-based in-situ electrochemical common combined testing device and a testing method, and can realize batch testing and characterization of positive and negative materials of a full battery, solves the problem that existing testing devices can only test single polarity, realizes in-situ XRD measurement of the positive electrode during battery charging and discharging, and can realize real-time observation of phase structure changes of the electrode material; when the testing device is used, the chemical structure, phase and morphology, crystallization and other information of the negative electrode can be obtained by inverting the battery, and the structures such as the electrode, the separator and the electrolyte in the battery can be clearly displayed in a CT diffractometer, thereby providing a strong and reliable technical platform and data support for in-situ revealing of complex failure mechanisms of the battery, analysis of reaction mechanisms and guidance of long-life battery material design.

[0005] The application is realized by the following technical schemes:

[0006] The application discloses a double-window detection-based in-situ electrochemical common combined testing device, which comprises an upper cover body and a lower cover body sealingly connected below the upper cover body, and a battery is arranged between the two cover bodies, two wiring assemblies are sealingly arranged below the lower cover body, the two wiring assemblies are in contact with two poles of the battery, and the two wiring assemblies are used for connecting the battery with an external circuit, a window A for transmitting X-rays is arranged at the center of the upper cover body, a window B for penetrating laser is arranged at the center of the lower cover body, and a lifting assembly for adjusting the height is arranged below the lower cover body.

[0007] As a further scheme, the upper cover body is a disc structure provided with a first through hole in the middle, and the first through hole is used for mounting the window A, and the upper cover body is further provided with threads for connecting with the lower cover body.

[0008] As a further scheme, the material of the window A is beryllium, diamond, boron nitride or polyimide film.

[0009] As a further scheme, the material of the upper cover body can penetrate the X-rays emitted by a CT testing device.

[0010] As a further scheme, the material of the upper cover body is any one or a combination of polyether ether ketone, polytetrafluoroethylene, polyethylene, polyethylene, polycarbonate or polystyrene.

[0011] As a further scheme, the inner diameter of the first through hole is larger than the size of a light source emitted by an XRD device.

[0012] As a further scheme, the inner diameter of the first through hole is 80±5 mm, and the diameter of the XRD window is 18±2 mm.

[0013] As a further scheme, the lifting assembly comprises a lifting base and a lifting circular table threadedly connected above the lifting base, the top of the lifting circular table is a platform and is used for being inserted into the third groove, and the lifting base is used for being connected with an XRD diffractometer goniometer.

[0014] As a further option, the diameter of the lifting base is 84±10mm; the diameter of the lifting platform is 32±

[0015] 10mm;

[0016] As a further solution, the lifting base is equipped with symmetrically positioned through holes, No. 4 grooves, positioning pin holes, magnetic discs, and screws;

[0017] As a further option, the middle part of the lifting base is also provided with a connecting part that is threadedly connected to the lifting platform.

[0018] As a further embodiment, the wiring assembly includes a terminal block and a terminal nut connected to one side, an externally fitted No. 3 sealing ring, one end of the terminal block passes through the No. 3 through hole and contacts one electrode of the battery, and the No. 3 sealing ring seals the terminal block and the No. 3 through hole.

[0019] As a further option, the terminal block is made of at least one of stainless steel and its alloys;

[0020] As a further option, the material of the terminal nut is polyetheretherketone or polytetrafluoroethylene;

[0021] As a further option, the hole diameter of the terminal nut is 3±2mm; the diameter of the terminal post is 3±2mm and the length is 20±10mm.

[0022] As a further embodiment, the lower cover body includes a lower cover body, which is a disc structure with a No. 2 through hole at the center. The No. 2 through hole is used to seal the installation window B. A No. 3 groove is provided at the center of one side of the lower cover body, and a No. 1 groove and a No. 2 groove for installing the battery are provided on the other side. The two ends of the No. 2 groove are respectively provided with a No. 3 through hole and a No. 4 through hole for installing the wiring assembly. The wiring assembly is sealed to the lower cover body and contacts the two poles of the battery for conduction.

[0023] As a further embodiment, the material of the lower cover body is capable of penetrating X-rays emitted by CT testing equipment;

[0024] As a further option, the material of the lower cover body is any one or more combinations of polyetheretherketone, polytetrafluoroethylene, polyethylene, polyethylene, polycarbonate or polystyrene.

[0025] As a further option, both groove No. 1 and groove No. 3 are circular grooves;

[0026] As a further option, the second groove is used to bond the first sealing ring and then connect it to the threaded connection of the upper cover body;

[0027] As a further option, the inner diameter of the No. 1 sealing ring is 10±2mm, the outer diameter is 15±2mm, and the thickness is 4±2mm.

[0028] As a further embodiment, the window B includes a second sealing ring, quartz glass and a sealing cover arranged sequentially from top to bottom. After the quartz glass and the second sealing ring are pressed together on the top of the sealing cover, it is fixedly connected to the second through hole.

[0029] As a further option, the sealing cover has a frustum structure and a symmetrical through groove on the side away from the lower cover body;

[0030] As a further embodiment, the inner diameter of window B is larger than the size of the light source emitted by the Ramman device;

[0031] As a further embodiment, the inner diameter of window B is 80±5mm, and the diameter of the light-transmitting hole is 6±2mm.

[0032] As a further option, quartz glass can be replaced with calcium fluoride glass, sapphire glass, or silicon glass.

[0033] This invention also provides an in-situ electrochemical common-mode test method based on dual-window detection, comprising the following steps:

[0034] S1. Prepare the soft-pack battery: Prepare the necessary materials for the battery at room temperature.

[0035] S2. Assemble the pouch battery: Under inert gas conditions, assemble the positive electrode material and the negative electrode material into a pouch battery.

[0036] S3. Assemble the in-situ device: Under inert gas conditions, place the soft-pack battery between the upper and lower covers, and connect the terminal nuts, terminals, and external wiring.

[0037] S4. In-situ electrochemical test: Connect the blue electric channel, record the initial voltage, start the test at the same time, record the voltage at the end of the test, and continue the test.

[0038] As a further option, the in-situ electrochemical testing in S4 includes in-situ XRD detection, in-situ...

[0039] Raman CT scan and in situ CT scan.

[0040] The features and beneficial effects of this invention are as follows:

[0041] The testing device:

[0042] The in-situ electrochemical common-use testing device based on dual-window detection proposed in this application enables simultaneous batch testing and characterization of positive and negative electrode materials in full-cell batteries. This solves the problem that existing testing devices can only test a single polarity, resulting in higher integration and avoiding increased testing costs caused by using multiple devices, thereby reducing testing costs. The testing device achieves in-situ XRD measurement of the positive electrode during battery charging and discharging by adjusting the height of the lifting component, enabling real-time observation of phase structure changes in the electrode material. When using this testing device, the chemical structure, phase and morphology, crystallization, and other information of the negative electrode can be obtained by inverting the battery. Furthermore, the internal structures of the battery, such as electrodes, separators, and electrolytes, can be clearly displayed in a CT diffractometer. This provides a powerful and reliable technical platform and data support for in-situ revelation of complex battery failure mechanisms, analysis of reaction mechanisms, and guidance for the design of long-life battery materials. It is more versatile and has a wider range of applications.

[0043] The testing method:

[0044] The testing method of this application can couple in-situ Raman spectroscopy, in-situ X-ray diffraction and in-situ X-ray tomography non-destructive characterization techniques to achieve simultaneous characterization of the composition, physical properties, crystal structure and three-dimensional structure of electrode materials. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is an exploded view of the in-situ electrochemical common-use test device based on dual-window detection as described in an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the lower cover body according to an embodiment of the present invention. Figure 1 ;

[0048] Figure 3 This is a schematic diagram of the lower cover body according to an embodiment of the present invention. Figure 2 ;

[0049] Figure 4 This is an exploded view of the lifting assembly described in an embodiment of the present invention;

[0050] Figure 5 This is a schematic diagram of the lifting base described in an embodiment of the present invention. Figure 1 ;

[0051] Figure 6 This is a schematic diagram of the lifting base described in an embodiment of the present invention. Figure 2;

[0052] Figure 7 This is a schematic diagram of the sealing cap according to an embodiment of the present invention;

[0053] Figure 8 This is an exploded view of the wiring assembly described in an embodiment of the present invention;

[0054] Figure 9 The in-situ XRD results of the lithium iron phosphate cathode in Example 1 of this invention from the initial state to the charging state;

[0055] Figure 10 for Figure 9 A magnified view of a portion of the image;

[0056] Figure 11 The in-situ XRD results of the graphite negative electrode in Embodiment 2 of the present invention during the first cycle from the charging state to the discharging state.

[0057] Figure 12 for Figure 11 A magnified view of a portion of the image;

[0058] Figure 13 This is the in-situ Raman result of the graphite negative electrode in Embodiment 3 of the present invention during the first cycle from the discharge state to the charge state;

[0059] Figure 14 for Figure 13 A magnified view of a portion of the image;

[0060] Figure 15 This is a spatial resolution measurement image of a soft-pack battery subjected to CT testing according to Embodiment 4 of the present invention;

[0061] Figure 16 This is a schematic diagram of the three-dimensional reconstruction of the soft-pack battery tested by CT in Embodiment 4 of the present invention;

[0062] Figure 17 This is a schematic diagram of the coronal plane of the soft-pack battery in Embodiment 4 of the present invention;

[0063] Figure 18 This is an enlarged cross-sectional view of Embodiment 4 of the present invention.

[0064] Explanation of reference numerals in the attached figures:

[0065] 1-Upper cover; 11-Through hole No. 1; 2-Lower cover; 21-Lower cover body; 22-Through hole No. 2; 23-Through hole No. 3; 24-Through hole No. 4; 25-Groove No. 1; 26-Sealing ring No. 1; 27-Groove No. 2; 28-Groove No. 3; 3-Battery; 4-Lifting assembly; 41-Lifting base; 411-Through hole; 412-Groove No. 4; 413-Positioning pin hole; 414-Magnetic disc; 415-Connecting part; 42-Lifting platform; 5-Sealing cover; 51-Through groove; 6-Wiring assembly; 61-Wiring nut; 62-Wiring post; 63-Sealing ring No. 3; 7-Sealing ring No. 2; 8-Quartz glass. Detailed Implementation

[0066] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below, and embodiments of the present invention will be provided, but this does not limit the scope of the present invention.

[0067] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0068] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0069] Definitions:

[0070] Ramman: Raman spectroscopy.

[0071] In-situ electrochemical common-use testing device based on dual-window detection, such as Figures 1 to 8As shown, it includes an upper cover 1 and a lower cover 2 sealed below it, with a battery 3 installed between the two. Two wiring assemblies 6 are sealed below the lower cover 2, and the two wiring assemblies 6 are in contact with the two poles of the battery 3 for connecting the battery 3 to an external circuit. A window A for transmitting X-rays is installed at the center of the upper cover 1, and a window B for transmitting lasers is sealed at the center of the lower cover 2. A lifting assembly 4 for adjusting the height is installed below the lower cover 2.

[0072] The upper cover 1 is a disc structure with a through hole 11 in the middle. The through hole 11 is used to install window A, which is used to transmit X-rays. The upper cover 1 is also provided with threads for connecting with the lower cover 2.

[0073] The inner diameter of the first through hole 11 is larger than the size of the light source emitted by the XRD equipment.

[0074] In some embodiments, the inner diameter of the first through hole 11 is 80±5mm, the diameter of the XRD window is 18±2mm, the length of the soft-pack battery is 35-40mm, the width is 30-35mm, and the thickness is 0.6mm±4mm.

[0075] The window A is made of materials such as beryllium, diamond, boron nitride, and polyimide film.

[0076] The material of the upper cover 1 is capable of penetrating X-rays emitted by the CT testing equipment. Preferably, the material of the upper cover 1 is any one or a combination of polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), polyethylene (PE), polycarbonate (PC), or polystyrene (PS).

[0077] The lower cover 2 includes a lower cover body 21 that is sealed to the upper cover 1. The lower cover body 21 is a disc structure with a second through hole 22 at its center. The second through hole 22 is used to seal the installation window B, which is used for laser penetration. A third groove 28 is provided at the center of one side of the lower cover body 21, and a first groove 25 for installing a first sealing ring 16 and a second groove 27 for installing a battery 3 are provided on the other side. The two ends of the second groove 27 are respectively provided with a third through hole 23 and a fourth through hole 24 for installing a wiring assembly 6. The wiring assembly 6 is sealed to the lower cover body 21 and contacts the battery 3 for conduction.

[0078] Preferably, both groove 25 and groove 28 are circular grooves.

[0079] In one embodiment, the inner diameter of the first sealing ring 26 is 10±2mm, the outer diameter is 15±2mm, and the thickness is 4±2mm.

[0080] The window B includes a second sealing ring 7, a quartz glass 8, and a sealing cover 5 arranged sequentially from top to bottom. The inner wall of the third groove 28 has internal threads, and the outer wall of the sealing cover 5 also has internal threads. The sealing cover 5 is threaded onto the quartz glass 8 and the second sealing ring 7, and then threadedly connected to the second through hole 22. When the bottom is irradiated by a laser, the laser will penetrate the sealing cover 5, the quartz glass 8, the second sealing ring 7, the third groove 28, the third through hole 23, and the fourth through hole 24.

[0081] In some embodiments, the sealing cap 5 has a frustum structure, and a symmetrical through groove 51 is provided on the side away from the lower cover body 21 to facilitate tightening of the sealing cap and ensure the sealing performance of the sealing cap 5.

[0082] Before testing, a polyimide film is pasted at the bottom of window A on the upper cover to ensure good sealing. The lower cover is sealed by the cooperation of sealing ring 26, sealing ring 7, and sealing ring 63 to ensure overall sealing. Because holes need to be drilled in the aluminum-plastic film during XRD testing of soft-pack batteries, the sealing function prevents water and oxygen from entering and causing battery failure. The internal testing pressure of the testing device is ensured by tightening the threads of the upper cover 1 and the lower cover 2. The testing device has a moderate positive pressure that allows all components (electrodes, separators) to be tightly attached together, ensuring good contact between the electrodes and the electrolyte, thereby ensuring low interfacial impedance and efficient ion / electron conduction.

[0083] The inner diameter of window B is larger than the size of the light source emitted by the Ramman device.

[0084] In some embodiments, the inner diameter of window B is 80±5mm, and the diameter of the light-transmitting hole is 6±2mm.

[0085] The wiring assembly 6 includes a terminal 62 and a terminal nut 61 fixedly connected to one side, and an externally fitted No. 3 sealing ring 63. One end of the terminal 62 passes through the No. 3 through hole 23 and contacts one end of the battery 3. At this time, the No. 3 sealing ring 63 is located between the terminal 62 and the No. 3 through hole 23, sealing the terminal 62 and the lower cover body 21.

[0086] In some embodiments, the terminal block 62 is made of at least one of stainless steel and its alloys.

[0087] In some embodiments, the wiring nut 61 is made of polyetheretherketone or polytetrafluoroethylene.

[0088] In some embodiments, the hole diameter of the terminal nut 61 is 3±2mm; the diameter of the terminal 62 is 3±2mm and the length is 20±10mm.

[0089] The material of the lower cover body 21 is capable of penetrating X-rays emitted by CT testing equipment.

[0090] In some embodiments, the material of the lower cover body 21 is any one or a combination of polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), polyethylene (PE), polycarbonate (PC), or polystyrene (PS).

[0091] In some embodiments, the quartz glass in window B may be replaced with calcium fluoride, sapphire, silicon, etc.

[0092] The materials of sealing ring 26 (No. 1), sealing ring 7 (No. 2), and sealing ring 63 (No. 3) are any one of nitrile rubber, fluororubber, silicone rubber, EPDM rubber, and polytetrafluoroethylene.

[0093] The lifting assembly 4 includes a lifting base 41 and a lifting platform 42 threadedly connected above it. The top of the lifting platform 42 is a platform for insertion into the third groove 28. The lifting base 41 is used to connect to an external XRD diffractometer goniometer.

[0094] In some embodiments, the diameter of the lifting base 41 is 84±10mm; the diameter of the lifting platform 42 is 32±10mm.

[0095] The lifting base 41 is provided with symmetrically positioned through holes 411, groove 412, positioning pin hole 413, magnetic disc 414 and screws. Groove 412, positioning pin hole 413, magnetic disc 414 and screws are used for different models of XRD diffractometers to facilitate connection with XRD diffractometers.

[0096] The middle part of the lifting base 41 is also provided with a connecting part 415 that is threadedly connected to the lifting platform 42. Among them, the fourth groove 412 serves as a limit. The through hole 411 is used to place the wiring nut 61 to prevent interference between the lifting base 4 and the wiring assembly 6.

[0097] In some embodiments, the lifting platform 42 and the lifting base 41 are made of any one or more combinations of polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), polyethylene (PE), polycarbonate (PC), or polystyrene (PS), and the magnetic disc 414 is made of at least one of stainless steel and its alloys.

[0098] In some embodiments, the lifting base 41 supports in-situ XRD measurements on an XRD device, enabling X-ray detection angles of 15° < 2θ < 90°, and real-time observation of phase structure changes in electrode materials during the charging and discharging process of the device.

[0099] The specific adjustment method for the lifting component 4 in the XRD diffractometer is as follows:

[0100] X1. Install lifting assembly 4: Install the lifting base 41 onto the XRD diffractometer goniometer, limit and position it through the fourth groove 412 and the positioning pin hole 413, and then pass the bolt through the through hole 411 to fix it to the XRD diffractometer goniometer.

[0101] X2. Setting the zero point: Connect the lifting stage 42 to the connecting part 415 via a thread. When the lifting stage 42 is adjusted to the middle position of the connecting part 415, use the laser collimation system of the XRD diffractometer to perform height calibration until the sample center is located at the center of the optical path. Set this position as the zero point.

[0102] X3. Install the mold: Place the third groove 28 on the lifting platform 42. At this time, the wiring nut 61 is located in the through hole 411. During the adjustment of the lifting component 4, the lifting component 4 and the wiring component 6 interfere with each other.

[0103] X4. Height Compensation: Rotate to lower the height of the lifting platform 42 until the laser point accurately hits the point where the sample diffraction signal is strongest again.

[0104] X5. Start the experiment: After completing the height compensation, the in-situ XRD test can be started.

[0105] The in-situ electrochemical common-coupled testing method based on dual-window detection includes the following steps:

[0106] S1. Prepare the pouch battery: Under room temperature conditions, prepare all the materials required for the battery.

[0107] S2. Assemble the pouch battery: Under inert gas conditions, place the positive electrode material and negative electrode material in the corresponding positions to assemble the pouch battery.

[0108] S3. Assemble the in-situ device: Under inert gas conditions, place the soft-pack battery between the upper cover 1 and the lower cover 2, connect the wiring nut, the terminal block and the external wiring, and take out the test device from the glove box.

[0109] S4. In-situ electrochemical test: Connect the blue electric channel, record the initial voltage, start the test at the same time, record the voltage at the end of the test, and continue the test.

[0110] The in-situ electrochemical testing in S4 includes in-situ XRD detection, in-situ Raman detection, and in-situ CT detection.

[0111] The pouch cell is normally loaded and placed on a diffractometer to collect diffraction signals of the positive electrode material; the cell is reversed and placed on a Raman spectrometer to collect Raman signals of the negative electrode, and can also be used for in-situ non-destructive characterization of the three-dimensional morphology of the cell. This can be used for the combined characterization of the composition, physical properties, crystal structure and three-dimensional structure of the cell material to be tested.

[0112] Example 1

[0113] An in-situ electrochemical common-mode test method based on dual-window detection includes the following steps:

[0114] A1. Prepare the soft-pack battery: Under room temperature conditions, cut the aluminum-plastic film, copper mesh, aluminum mesh, and glass fiber separator according to the size of the second groove 27 of the lower cover 2 of the test device. Make a hole with a diameter of 18mm on one side of the aluminum-plastic film, and roll the positive electrode material lithium manganese iron phosphate onto the aluminum mesh.

[0115] A2. Assemble the soft-pack battery: At room temperature, in a glove box filled with argon inert gas, place the positive electrode lithium iron phosphate facing the perforated side of the aluminum-plastic film, and roll the negative electrode lithium sheet onto the copper mesh facing the unperforated side.

[0116] A3. Assemble the in-situ device: At room temperature, seal window A with a polyimide film; after pressing the quartz glass and the second sealing ring onto the top of the sealing cover, fix the window B to the second through hole. At room temperature, in a glove box filled with argon inert gas, place the soft-pack battery with the perforated side facing the upper cover 1, and apply sealant to the threads of the upper cover 1 and lower cover 2 for sealing. Connect the terminal nut 61, terminal 62, and external wiring, gently press the terminal 62 to ensure good contact between the terminal and the battery tab, and remove the in-situ device from the glove box.

[0117] A4. In-situ XRD Testing: First, install the lifting base 41 onto the goniometer of the XRD diffractometer. Then, adjust the lifting platform 42 threaded to the middle position of the lifting base 41. Use the laser collimation system of the XRD diffractometer for height calibration, ensuring the sample center is located at the center of the optical path. Set this position as the zero point. Place the third groove 28 on the lifting platform 42 and rotate it to lower the height until the laser point accurately hits the point of strongest diffraction signal in window A again. Connect the external wiring to the blue electric channel, close the XRD diffractometer door lock, record the initial voltage, and simultaneously start the electrochemical test and XRD test. After the XRD test is completed, record the voltage again and continue testing. This testing device can acquire X-ray diffraction spectrum data online during normal charging and discharging.

[0118] Test results, such as Figures 9-10 As shown. From Figure 9 The in-situ XRD results of the lithium manganese iron phosphate cathode from its initial state to its charged state are presented visually. A group of 19 data points at different voltages is used to visualize the process. Figure 10 for Figure 9 The magnified view of the part shows that the appearance of new characteristic peaks under overcharge voltage indicates that lithium manganese iron phosphate has undergone a delithiation phase transition, confirming that the in-situ device can collect X-ray diffraction data online during normal charging and discharging.

[0119] Example 2

[0120] An in-situ electrochemical common-mode test method based on dual-window detection includes the following steps:

[0121] B1. Prepare the soft-pack battery: Under room temperature conditions, cut the aluminum-plastic film, copper mesh, aluminum mesh, and glass fiber separator according to the size of the second groove 27 of the lower cover 2 of the test device. Make a hole with a diameter of 18mm on one side of the aluminum-plastic film and roll the negative electrode material graphite onto the copper mesh.

[0122] B2. Assemble the soft-pack battery: At room temperature, in a glove box filled with argon inert gas, place the negative electrode graphite facing the perforated side of the aluminum-plastic film, and roll the positive electrode sodium sheet onto the aluminum mesh facing the unperforated side.

[0123] B3. Assemble the in-situ device: At room temperature, seal window A with a polyimide film; after pressing the quartz glass and the second sealing ring onto the top of the sealing cover, fix the window B to the second through hole. At room temperature, in a glove box filled with argon inert gas, place the soft-pack battery with the perforated side facing the upper cover 1, and apply sealant to the threads of the upper cover 1 and lower cover 2 for sealing. Connect the terminal nut 61, terminal 62, and external wiring, gently press the terminal 62 to ensure good contact between the terminal and the battery tab, and remove the in-situ device from the glove box.

[0124] B4. In-situ XRD Testing: First, install the lifting base 41 onto the goniometer of the XRD diffractometer. Then, adjust the lifting platform 42 to the middle position of the lifting base 41 using the thread. Use the laser collimation system of the XRD diffractometer to perform height calibration, ensuring the sample center is located at the center of the optical path. Set this position as the zero point. Place the third groove 28 on the lifting platform 42 and rotate it to lower the height until the laser point accurately hits the point of strongest diffraction signal in window A again. Connect the external wiring to the blue electric channel, close the XRD diffractometer door lock, record the initial voltage, and simultaneously start the electrochemical test and XRD test. After the XRD test is completed, record the voltage again and continue testing. During normal charging and discharging, this testing device can acquire X-ray diffraction spectrum data online.

[0125] Test results, such as Figure 11 and Figure 12 As shown. Figure 11 This is the in-situ XRD result of the graphite anode during the first cycle from the charging state to the discharging state. A curve is taken for every 0.2V change, and 21 data points at different voltages are plotted together. Figure 12The image is a magnified view of a portion of the image. It can be seen that the initial graphitization intensity is relatively strong. During the gradual discharge process, as sodium ions are inserted, the graphitization intensity weakens, and then the intensity of the charging peak recovers. This also confirms that the in-situ device can collect X-ray diffraction data online during normal charging and discharging.

[0126] Example 3

[0127] An in-situ electrochemical common-mode test method based on dual-window detection includes the following steps:

[0128] C1. Prepare the soft-pack battery: Under room temperature conditions, cut the aluminum-plastic film, copper mesh, aluminum mesh, and glass fiber separator according to the size of the second groove 27 of the lower cover 2 of the test device. A hole with a diameter of 12mm is punched on one side of the aluminum-plastic film, and the negative electrode material graphite is rolled onto the copper mesh.

[0129] C2. Assemble the soft-pack battery: At room temperature, in a glove box filled with argon inert gas, place the negative electrode graphite facing the perforated side of the aluminum-plastic film and the positive electrode sodium sheet facing the unperforated side.

[0130] C3. Assemble the in-situ device: At room temperature, seal window A with a polyimide film; after pressing the quartz glass and the second sealing ring onto the top of the sealing cover, fix the window B to the second through hole. At room temperature, in a glove box filled with argon inert gas, place the soft-pack battery with the perforated side facing the upper cover 1, and apply sealant to the threads of the upper cover 1 and lower cover 2 for sealing. Connect the terminal nut 61, terminal 62, and external wiring, gently press the terminal 62 to ensure good contact between the terminal and the battery tab, and remove the in-situ device from the glove box.

[0131] C4. In-situ Raman test: Place the lower cover 2 of the test device with one side facing upwards, focus the laser at window B of the test device, connect the external wire to the blue electric channel, record the initial voltage, and start the electrochemical test and Raman spectroscopy test at the same time. After the Raman spectroscopy acquisition is completed, record the voltage at the same time and continue to acquire. During the normal charging and discharging process of this in-situ device, it can acquire Raman spectra online.

[0132] Test results, such as Figure 13 and Figure 14 As shown. From Figure 13 This study aims to visualize the in-situ Raman spectroscopy results of the graphite anode during its first cycle, transitioning from a discharge to a charge state. The results are obtained by plotting 16 data points at different voltages. Figure 14As can be seen, the initial graphitization is strong, indicating an ordered structure. During gradual discharge, the graphitization weakens with the insertion of sodium ions, indicating a stronger degree of disorder. Then, the peak intensifies after charging, indicating a return to an ordered structure. This confirms that during battery use, normal sample loading and diffraction signal acquisition of the positive electrode material can be performed on a diffractometer; and Raman signal acquisition of the negative electrode can be performed by inverting the battery on a Raman spectrometer.

[0133] Example 4

[0134] An in-situ electrochemical common-mode test method based on dual-window detection includes the following steps:

[0135] D1. Prepare the soft-pack battery: Under room temperature conditions, cut the aluminum-plastic film, copper mesh, aluminum mesh, and glass fiber separator according to the size of the second groove 27 of the lower cover 2 of the test device. Make a hole with a diameter of 18mm on one side of the aluminum-plastic film and roll the positive electrode material lithium manganese iron phosphate onto the aluminum mesh.

[0136] D2. Assemble the soft-pack battery: At room temperature, in a glove box filled with argon inert gas, place the positive electrode lithium iron phosphate facing the perforated side of the aluminum-plastic film, and roll the negative electrode lithium sheet onto the copper mesh facing the unperforated side.

[0137] D3. Assemble the in-situ device: At room temperature, attach window A with polyimide film; after pressing the quartz glass and sealing ring No. 2 onto the top of the sealing cover, fix window B to the through hole No. 2. At room temperature, in a glove box filled with argon inert gas, place the soft-pack battery with the perforated side facing the upper cover 1, and apply sealant to the threads of the upper cover 1 and lower cover 2 for sealing. Connect the terminal nut 61, terminal 62, and external wiring, gently press terminal 62 to ensure good contact between the terminal and the battery tab, and remove the in-situ device from the glove box.

[0138] D4. In-situ CT test: Fix the test device on the CT rotating sample stage of the CT tester, connect the external wire to the blue electric channel to charge to 4.99V, and perform the test in the CT tester.

[0139] Test results, such as Figures 15 to 18 The spatial resolution was measured by edge response analysis. Five points were calibrated, with resolutions of 1.2, 1.3, 1.3, 1.1 and 1.2 μm, respectively, and an average resolution of 1.22 μm, as shown in Table 1. Table 1 shows the spatial resolution measurement results of the in-situ common mold used in this invention for CT testing.

[0140] Table 1

[0141] Edge selection 1 2 3 4 5 Mean value Spatial resolution (pm) 1.2 1.3 1.3 1.1 1.3 1.22

[0142] As can be seen from Table 1, after CT testing using the test mold described in this invention, the analysis results show that the average spatial resolution of the three-dimensional space of the in-situ common mold reached 1.22 μm.

[0143] In summary, the in-situ electrochemical common-use testing device based on dual-window detection proposed in this application can achieve simultaneous batch testing and characterization of positive and negative electrode materials in full-cell batteries. This solves the problem that existing testing devices can only test a single polarity, resulting in higher integration and avoiding the increased testing costs caused by using multiple devices, thereby reducing testing costs. The testing device achieves in-situ XRD measurement of the positive electrode during battery charging and discharging by adjusting the height of the lifting component 4, enabling real-time observation of phase structure changes in the electrode material. When using this testing device, the chemical structure, phase and morphology, crystallization, and other information of the negative electrode can be obtained by inverting the battery. Furthermore, the internal structures of the electrode, separator, and electrolyte can be clearly displayed in a CT diffractometer. This provides a powerful and reliable technical platform and data support for in-situ revelation of complex battery failure mechanisms, analysis of reaction mechanisms, and guidance for the design of long-life battery materials. It is more versatile and has a wider range of applications. The testing method proposed in this application can couple in-situ Raman spectroscopy, in-situ X-ray diffraction, and in-situ X-ray tomography non-destructive characterization techniques to achieve simultaneous characterization of the electrode material's composition, properties, crystal structure, and three-dimensional structure.

[0144] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An in-situ electrochemical common-mode testing device based on dual-window detection, characterized in that: It includes an upper cover and a lower cover that is sealed and connected below it, with a battery installed between the two. Two wiring assemblies are sealed and installed below the lower cover, and the two wiring assemblies are in contact with the two poles of the battery for connecting the battery to an external circuit. A window A for transmitting X-rays is installed at the center of the upper cover, and a window B for transmitting lasers is installed at the center of the lower cover. A lifting assembly for adjusting the height is installed below the lower cover.

2. The in-situ electrochemical common-mode testing device based on dual-window detection according to claim 1, characterized in that: The upper cover is a disc structure with a through hole in the middle. The through hole is used to install window A. The upper cover is also provided with threads for connecting with the lower cover. Preferably, the material of window A is beryllium, diamond, boron nitride, or polyimide film; Preferably, the material of the upper cover is capable of penetrating X-rays emitted by the CT testing equipment; Preferably, the material of the upper cover is any one or more combinations of polyetheretherketone, polytetrafluoroethylene, polyethylene, polyethylene, polycarbonate or polystyrene.

3. The in-situ electrochemical common-mode testing device based on dual-window detection according to claim 2, characterized in that: The inner diameter of the first through-hole is larger than the size of the light source emitted by the XRD equipment; Preferably, the inner diameter of the first through hole is 80±5mm, and the diameter of the XRD window is 18±2mm.

4. The in-situ electrochemical common-mode testing device based on dual-window detection according to claim 1, characterized in that: The lifting assembly includes a lifting base and a lifting platform threadedly connected above it. The top of the lifting platform is a platform for insertion into the No. 3 groove. The lifting base is used to connect to an external XRD diffractometer goniometer. Preferably, the diameter of the lifting base is 84±10mm; the diameter of the lifting platform is 32±10mm. Preferably, the lifting base is provided with symmetrically positioned through holes, No. 4 grooves, positioning pin holes, magnetic discs, and screws; Preferably, the middle part of the lifting base is also provided with a connecting part that is threadedly connected to the lifting platform.

5. The in-situ electrochemical common-use testing device based on dual-window detection according to claim 1, characterized in that: The wiring assembly includes a terminal block and a terminal nut connected to one side, and an externally fitted No. 3 sealing ring. One end of the terminal block passes through the No. 3 through hole and contacts one electrode of the battery, and the No. 3 sealing ring seals the terminal block and the No. 3 through hole. Preferably, the terminal block is made of at least one of stainless steel and its alloys; Preferably, the material of the terminal nut is polyetheretherketone or polytetrafluoroethylene; Preferably, the hole diameter of the terminal nut is 3±2mm; the diameter of the terminal post is 3±2mm and the length is 20±10mm.

6. The in-situ electrochemical common-mode testing device based on dual-window detection according to claim 1, characterized in that: The lower cover body includes a lower cover body, which is a disc structure with a No. 2 through hole at the center. The No. 2 through hole is used to seal the installation window B. A No. 3 groove is provided at the center of one side of the lower cover body, and a No. 1 groove and a No. 2 groove for installing the battery are provided on the other side. The two ends of the No. 2 groove are respectively provided with a No. 3 through hole and a No. 4 through hole for installing the wiring assembly. The wiring assembly is sealed to the lower cover body and contacts the two poles of the battery for conduction. Preferably, the material of the lower cover body is capable of penetrating X-rays emitted by the CT testing equipment; Preferably, the material of the lower cover body is any one or more combinations of polyetheretherketone, polytetrafluoroethylene, polyethylene, polyethylene, polycarbonate or polystyrene; Preferably, both groove No. 1 and groove No. 3 are circular grooves; Preferably, the second groove is used to bond the first sealing ring and then connect it to the upper cover via a threaded connection; Preferably, the inner diameter of the No. 1 sealing ring is 10±2mm, the outer diameter is 15±2mm, and the thickness is 4±2mm.

7. The in-situ electrochemical common-mode testing device based on dual-window detection according to claim 6, characterized in that: The window B includes a second sealing ring, quartz glass and a sealing cover arranged sequentially from top to bottom. After the quartz glass and the second sealing ring are pressed together on the top of the sealing cover, it is fixedly connected to the second through hole. Preferably, the sealing cover has a frustum structure and a symmetrical through groove is provided on the side away from the lower cover body; Preferably, the inner diameter of window B is larger than the size of the light source emitted by the Ramman device; Preferably, the inner diameter of window B is 80±5mm, and the diameter of the light-transmitting hole is 6±2mm.

8. The in-situ electrochemical common-mode testing device based on dual-window detection according to claim 7, characterized in that: Quartz glass can be replaced with calcium fluoride glass, sapphire glass, or silicon glass.

9. The test method of the in-situ electrochemical common-mode test device based on dual-window detection according to any one of claims 1 to 8, characterized in that: Includes the following steps: S1. Prepare the soft-pack battery: Prepare the necessary materials for the battery at room temperature. S2. Assemble the pouch battery: Under inert gas conditions, assemble the positive electrode material and the negative electrode material into a pouch battery. S3. Assemble the in-situ device: Under inert gas conditions, place the soft-pack battery between the upper and lower covers, and connect the terminal nuts, terminals, and external wiring. S4. In-situ electrochemical test: Connect the blue electric channel, record the initial voltage, start the test at the same time, record the voltage at the end of the test, and continue the test.

10. The in-situ electrochemical common-mode test method based on dual-window detection according to claim 9, characterized in that: The in-situ electrochemical testing in S4 includes in-situ XRD detection, in-situ Raman detection, and in-situ CT detection.

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