Electrode particle optical image sequence acquisition method and in-situ optical cell characterization method

Abstract

The invention relates to the technical field of image processing and optical detection, in particular to an electrode particle optical image sequence acquisition method and an in-situ optical cell characterization method. When an optical imaging system is adopted to collect an optical image sequence of an electrode particle image at a to-be-detected battery pole piece of an in-situ battery module arranged at a three-dimensional displacement platform, the method comprises the following steps: establishing a scanning path point set of the three-dimensional displacement platform; driving the three-dimensional displacement platform to sequentially move to each scanning path point in the scanning path point set point by point, and constructing a target spatial database based on recognition of the target electrode particles; setting the number of cycles, performing traversal imaging on all the target electrode particles in the target spatial database, and constructing an optical image sequence of all the target electrode particles, thereby remarkably improving the image quality and the reliability of observation data.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery testing, in particular to an electrode particle optical image sequence acquisition method and an in-situ optical battery characterization method. BACKGROUND

[0002] Batteries are the core power source of electric vehicles and portable electronic devices. In order to further improve their performance, it is necessary to deeply understand the working mechanism of electrode materials at the microscopic level. In order to optimize battery materials and break through the rate performance bottleneck, it is particularly necessary to observe the lithium ion insertion / extraction dynamics, phase change behavior and their correlation with macroscopic electrochemical performance in real time at the single particle level. However, electrode materials exhibit complex heterogeneity and dynamic changes during operation and cycling, making it difficult to accurately and visually track and quantify them using traditional electrochemical methods.

[0003] In the face of this problem, a variety of advanced in-situ characterization techniques have been developed and applied, such as in-situ transmission electron microscopy, in-situ scanning electron microscopy, transmission X-ray microscopy, scanning confocal Raman microscopy, etc. Among them, in-situ transmission electron microscopy and in-situ scanning electron microscopy can provide extremely high spatial resolution for observing the microstructure evolution of materials; transmission X-ray microscopy based on a synchrotron radiation source has strong penetration ability and chemical analysis function; scanning confocal Raman microscopy can provide rich molecular fingerprint information. These techniques can observe single particles to some extent, but they all have certain limitations, i.e., they are costly, complex to operate, difficult to prepare samples, may cause beam damage, slow imaging speed, and require harsh geometric structures of the battery, etc. Therefore, existing in-situ characterization techniques have deficiencies in cost, operation, and maintaining sample integrity. SUMMARY

[0004] To solve certain or some defects of the prior art, the present disclosure provides an electrode particle optical image sequence acquisition method and an in-situ optical battery characterization method.

[0005] According to an electrode particle optical image sequence acquisition method of the present application, when an optical imaging system is used to acquire an optical image sequence of electrode particle images at a battery electrode sheet to be tested of an in-situ battery module disposed at a three-dimensional displacement platform, the method comprises,

[0006] establishing a set of scanning path points of the three-dimensional displacement platform;

[0007] driving the three-dimensional displacement platform to move to each scanning path point in the set of scanning path points in sequence, and based on the identification of the target electrode particle, constructing a target space database;

[0008] Set the number of iterations, perform traversal imaging of all target electrode particles in the target spatial database, and construct an optical image sequence of all target electrode particles.

[0009] In this invention, an in-situ battery module containing the sample (i.e., the battery electrode to be tested) is fixed on a three-dimensional displacement platform. The platform scans different positions of the sample point by point. Specifically, after placing the experimental sample, the platform moves the sample to determine if there are target particles within the imaging area. If no target particles are found, the platform moves to the next position. If target particles are present, the platform's position coordinates are recorded, and the target particle image is cropped (to reduce data volume). The center position of the target particle in the cropped image is recorded. The platform then moves to the next position. After all scans are completed, the three-dimensional coordinates of several target particles, the image center coordinates, and the corresponding serial numbers of the target particles are obtained, thus establishing a set of scanning path points for the three-dimensional displacement platform. Data acquisition then begins. According to the process, at the start of acquisition, the 3D displacement platform is moved to the position of the target particle. At this time, the image of the cropped particle n will be displayed in the image acquisition frame. The z-axis movement in the 3D displacement platform is used to achieve automatic focusing and find the z-axis coordinate corresponding to the best focal point. The 3D displacement platform moves the sample to this z-axis coordinate, so that the image update in the acquisition frame is kept at the clearest focal length. The image at this time is then acquired and stored, and the z-axis coordinate of particle n in the target particle coordinate table is updated. Next, it moves to the position of target particle n+1 and executes the next acquisition step. Assuming that the acquisition of images of particles 1 to n is completed, it is considered one acquisition cycle. The number of cycles is preset, and all target electrode particles in the target spatial database are traversed and imaged to construct an optical image sequence of all target electrode particles.

[0010] Preferably, the expression for the set of scanned path points P is: ;

[0011] in, This represents the i-th scan path point in the set of scan path points P. , and Indicates scanning path points The x-axis displacement, y-axis displacement, and z-axis displacement.

[0012] The present invention first initializes the system to ensure that the scanning path covers the entire sample area to be tested. The scanning path point set is obtained through pre-scanning to identify and record the initial spatial state of all target particles.

[0013] Preferably, the three-dimensional displacement platform is driven to move sequentially point by point to each scanning path point in the set of scanning path points. Based on the identification of the target electrode particles, a target spatial database is constructed, including acquiring the original image of the current field of view through an optical imaging system when the three-dimensional displacement platform moves to any scanning path point in the set of scanning path points.

[0014] The system determines whether target electrode particles exist in the original image. If not, it controls the 3D displacement platform to move to the next scanning path point. If they exist, it uses the current order n of the target electrode particle as the corresponding target electrode particle number and the coordinates of the current scanning path point as the platform coordinates of the corresponding target electrode particle. And the image coordinates of the target electrode particles in the original image. As the image center coordinates of the corresponding target electrode particles;

[0015] The identification of all target electrode particles, number n, and platform coordinates. Image center coordinates and the corresponding target image Construct the target space database Q;

[0016] in, ;

[0017] in, This represents the nth data entry in the target spatial database Q.

[0018] This invention, after traversing all predetermined locations, integrates the serial numbers, initial platform coordinates, initial image center coordinates, and associated cropped images of all successfully identified target particles to form an initial target spatial database. By establishing this database and introducing visual feedback and motion compensation mechanisms in subsequent acquisition cycles, high-throughput, high-precision, and long-term stable automatic observation can be achieved. Specifically, before the experiment officially begins, a pre-scanning process is executed to identify and record the initial spatial state of all target particles to construct the target spatial database, which improves the efficiency of subsequent data acquisition and correction.

[0019] Preferably, for any target electrode particle, the corresponding original image is cropped to obtain a sub-image region containing the corresponding target electrode particle, which is then used as the corresponding target image. ;

[0020] In this context, the image coordinates of the feature points or centroids of the target electrode particles in the original image are used as the corresponding image center coordinates. .

[0021] By cropping the original image, the amount of data can be reduced and the data can be simplified to avoid unnecessary waste of computing power. Then, the image coordinates of the feature points or centroids of the target electrode particles in the original image are recorded, and the serial number of the target particles and the coordinates of the image center are collected.

[0022] Preferably, a set number of iterations is used to perform traversal imaging of all target electrode particles in the target spatial database, constructing an optical image sequence of all target electrode particles, including...

[0023] In a single traversal loop, all target electrode particles in the target spatial database Q are sequentially traversed and imaged.

[0024] For any target electrode particle, the target image acquired in each traversal cycle corresponds to that target electrode particle. This is an optical image sequence corresponding to the target electrode particles.

[0025] Preferably, in a single traversal cycle, traversal imaging of any target electrode particle includes,

[0026] Retrieve the corresponding platform coordinates from the target space database Q. Control the three-dimensional displacement platform to move to the corresponding position;

[0027] Based on planar position compensation, the x-axis compensation amount and y-axis compensation amount of the three-dimensional displacement platform are obtained;

[0028] Based on focus compensation, the z-axis compensation amount of the three-dimensional displacement platform is obtained;

[0029] Platform coordinates based on x-axis compensation, y-axis compensation, and z-axis compensation. Perform an update and control the 3D displacement platform to move to the updated platform coordinates. At this location, complete the corresponding target image. The collection.

[0030] Preferably, based on planar position compensation, the x-axis compensation and y-axis compensation of the three-dimensional displacement platform are obtained, including:

[0031] Control the 3D displacement platform to move to the previous platform coordinates. At this point, focus compensation is performed to obtain the z-axis compensation amount of the three-dimensional displacement platform;

[0032] Z-axis offset of a three-dimensional displacement platform controlled by Z-axis compensation;

[0033] Acquire the first raw image;

[0034] Based on the feature points or centroids of the target electrode particles, the image coordinates of the first original image and the corresponding image center coordinates The deviation is used to obtain the x-axis compensation amount. and y-axis compensation amount ;

[0035] Based on x-axis compensation amount and y-axis compensation amount Control the x-axis and y-axis offset of the three-dimensional displacement platform;

[0036] Acquire a second original image, and obtain the corresponding target image based on cropping of the second original image. .

[0037] This invention transforms image calibration from "post-processing" to "real-time intervention" by real-time detection and adjustment during the acquisition process, thereby obtaining stable optical image sequences, improving image quality, and ensuring the reliability of long-term observation.

[0038] As a preferred option, focus compensation is achieved based on an external calibration laser.

[0039] This invention transforms the minute displacement of a sample in the Z-axis direction into linear movement of a laser spot on the detector plane, thereby achieving nanometer-level precision displacement sensing and feedback control.

[0040] As a preferred method, focus compensation is achieved based on the gradient extreme focal length calibration algorithm.

[0041] This invention provides a focus calibration method based on image sharpness, also known as contrast-detection autofocus. It is a passive, self-contained calibration method that eliminates the need for additional laser sources and feedback optical paths, directly utilizing information from the imaging optical path itself for focus determination. The core principle of this method is that when the sample is at its optimal focal plane, the local contrast or high-frequency components (i.e., edge information) of its optical image are richest, resulting in the clearest image. In situations where high optical path simplicity is required or additional lasers cannot be introduced, the image information itself serves as a feedback signal, achieving fully automatic and adaptive focus maintenance, effectively improving the overall contrast and usability of the image sequence.

[0042] The present invention also provides an in-situ optical cell characterization method, which uses the above-mentioned optical image sequence acquisition method to acquire optical image sequences of electrode particles during the working process of the battery electrode sheet under test; and based on the processing of the optical image sequence, in-situ characterization of the battery electrode sheet under test is achieved.

[0043] This invention enables fully automated and synchronized control from electrochemical stimulation to optical response acquisition, greatly improving the repeatability, reliability, and throughput of experiments. Attached Figure Description

[0044] Figure 1This is a schematic diagram of the composition of the in-situ optical cell characterization device in this embodiment.

[0045] Figure 2 This is an overall schematic diagram of the in-situ optical cell characterization device in this embodiment.

[0046] Figure 3 This is a schematic diagram of a vibration isolation device in this embodiment.

[0047] Figure 4 This is a schematic diagram of the in-situ test mold in this embodiment.

[0048] Figure 5 This is an exploded view of the in-situ test mold in this embodiment.

[0049] Figure 6 This is an exploded view of the temperature-controlled in-situ battery module in this embodiment.

[0050] Figure 7 This is a cross-sectional schematic diagram of the temperature-controlled in-situ battery module in this embodiment.

[0051] Figure 8 This is a cross-sectional schematic diagram of the temperature-controlled in-situ battery module in this embodiment.

[0052] Figure 9 This is a schematic diagram of the temperature control module in this embodiment.

[0053] Figure 10 This is a schematic diagram of the optical path in this embodiment.

[0054] Figure 11 This is another schematic diagram of the optical path in this embodiment.

[0055] Figure 12 This is a comparison chart of the electrochemical performance of the in-situ battery module and the standard coin cell in this embodiment.

[0056] Figure 13 This is a comparison of the imaging effects of the optical system imaging and SEM imaging in this embodiment.

[0057] Figure 14 This is a schematic diagram of 65 particle image sequences acquired simultaneously using the optical image sequence acquisition method for electrode particles disclosed herein.

[0058] Figure 15 This is a schematic diagram illustrating the characterization of the lithium cobalt oxide phase transition process using an in-situ optical cell characterization method disclosed herein. Detailed Implementation

[0059] To further understand the content of this invention, the invention will be described in detail with reference to the embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0060] like Figure 1 , Figure 2 As shown, this disclosure provides an in-situ optical battery characterization device, which includes a support base 100, an in-situ battery module and an optical imaging system disposed at the support base 100. The in-situ battery module is used to connect to a battery comprehensive tester to simulate the battery working process, and the optical imaging system is used to acquire images of electrode particles at the electrode sheet of the battery under test during the working process of the in-situ battery module.

[0061] The above methods enable the construction of a rapid, low-cost imaging platform for visualizing and quantifying ion dynamics at the single-particle level. Furthermore, the introduction of a three-dimensional displacement platform allows for the acquisition of multiple particles from the same battery unit, characterizing spatial heterogeneity on the same electrode and providing more comprehensive guidance for battery design and optimization. The support base 100 primarily provides the stable environment required for the experiment. The electrode sample to be tested is placed in the in-situ battery module, which provides the pressure, gas, and temperature environment required for normal battery operation, ensuring the normal electrochemical performance of the electrode materials. The in-situ battery module performs real-time acquisition and calibration of optical images through an image acquisition unit and image calibration system, enabling long-term, rapid, and stable monitoring and analysis.

[0062] like Figure 3 As shown in this disclosure, the bearing base 100 includes a vibration isolation device and a bearing platform 330. The vibration isolation device includes an elastic component 310 and a viscous damping component 320. The elastic component 310 is used to suspend the bearing platform 330. The viscous damping component 320 includes silicone oil and a damping member 321 immersed in the silicone oil. The damping member 321 is fixedly connected to the bearing platform 330.

[0063] By integrating all modules onto a support base 100 that provides a stable vibration isolation environment for optical experiments, the support stage 330 integrates all modules used for optical experiments, and the vibration isolation device reduces the impact of mechanical vibration on experimental accuracy through reasonable design and optimization, thereby reducing the impact on the entire in-situ optical cell characterization device.

[0064] The design of the suspension platform 330 via the elastic component 310 effectively isolates common low-frequency vibrations (1Hz to 10Hz) in buildings, such as interference from people walking, equipment operation, or environmental noise, thereby reducing interference from the laboratory building to experiments. The elastic component 310 can use steel springs, which have good anti-creep properties and can bear heavy loads for a long time without deformation, making them suitable for long-term experimental needs. The viscous damping component can further improve the vibration isolation performance. By immersing the damping element in silicone oil, vibration reduction in all six degrees of freedom (including translation and rotation) is achieved. To achieve better results, a sphere is selected for the damping element, and high-viscosity silicone oil is selected. This design effectively reduces the coupling phenomenon between different degrees of freedom of vibration and optimizes the vibration attenuation efficiency, performing particularly well in the frequency range of 1Hz to 10Hz. This vibration isolation device is not only inexpensive but also superior in performance, especially in isolating low-frequency vibrations. The design of the bearing base 100 using this vibration isolation device is also highly flexible, and can be adjusted according to different requirements of load, spring constant and damping coefficient to adapt to different experimental environments.

[0065] like Figure 4 , 5 As shown in this disclosure, the in-situ battery module includes a room temperature in-situ battery module;

[0066] The ambient temperature in-situ battery module includes a main housing 410, one end of which is fixed to a base 420 by screws, and the other end of which is fixed to a cover plate 430 by screws.

[0067] A transparent substrate 440 is disposed between the base 420 and the main housing 410, and a first sealing ring is disposed between the transparent substrate 440 and the main housing 410; a second sealing ring is disposed between the cover plate 430 and the main housing 410.

[0068] One end of the main housing 410 forms a first battery cavity 411 for filling electrolyte. Inside the first battery cavity 411, in a direction away from the one end, the battery electrode to be tested, the insulating membrane, the auxiliary electrode and the sliding first metal pressure block 450 are arranged in sequence.

[0069] A spring cavity 412 is provided through the first battery cavity 411 and the other end of the main housing 410. A second metal pressure block 460 is slidably provided in the spring cavity 412. A metal spring is provided between the first metal pressure block 450 and the second metal pressure block 460. A first auxiliary electrode lead-out threaded hole 431 is provided on the cover plate 430 corresponding to the spring cavity 412. A first auxiliary electrode lead-out threaded post is provided at the first auxiliary electrode lead-out threaded hole 431 with thread engagement. The outer diameter of the first auxiliary electrode lead-out threaded post does not exceed the inner diameter of the spring cavity 412.

[0070] The main housing 410 is also provided with an eccentrically axially extending lead-out channel 413 for the first battery electrode to be tested, and the base 420 is provided with a first observation hole 421 at the battery electrode to be tested for cooperation with the optical imaging system.

[0071] In-situ battery modules can form a sealed cavity without participating in electrochemical reactions, providing the pressure, gas, and temperature environment required for normal battery operation and ensuring the normal electrochemical performance of the electrode materials (battery electrodes under test). Figure 12 As shown, the in-situ battery module in this disclosure has almost the same electrochemical performance as a standard coin cell. Meanwhile, the transparent substrate 440, i.e., the transparent glass substrate, located at one end of the sealed cavity facilitates optical observation.

[0072] like Figures 6-8 As shown in this disclosure, the in-situ battery module also includes a temperature-controlled in-situ battery module;

[0073] The temperature-controlled in-situ battery module includes a heat-conducting housing 610 made of metal, and a mounting base 620 is fixed to one end of the heat-conducting housing 610 by screws.

[0074] A transparent baffle 630 is provided between the mounting base 620 and the heat-conducting housing 610, and a third sealing ring is provided between the transparent baffle 630 and the heat-conducting housing 610;

[0075] A second battery cavity 611 for filling electrolyte is formed at one end of the heat-conducting housing 610. Inside the second battery cavity 611, in the direction away from the first end, the battery electrode to be tested, the insulating membrane, the auxiliary electrode, the third metal pressure block and the fourth metal pressure block are arranged sequentially. The third metal pressure block can be, for example, a stainless steel gasket, and the fourth metal pressure block can be, for example, a stainless steel spring sheet, nickel foam, etc.

[0076] A second auxiliary electrode lead-out threaded hole 612 is provided radially on the side wall of the heat-conducting housing 610, and a second auxiliary electrode lead-out threaded post is provided at the second auxiliary electrode lead-out threaded hole 612;

[0077] The heat-conducting housing 610 is also eccentrically provided with a second lead-out channel 613 for the battery electrode under test along the axial direction, and the mounting base 620 corresponds to the second observation hole 621 of the battery electrode under test for cooperation with the optical imaging system.

[0078] According to this disclosure, the heat-conducting housing 610 is made entirely of stainless steel, which has excellent thermal conductivity. The mold also ensures that it forms a sealed cavity without participating in the electrochemical reaction itself. The metal heat-conducting housing 610, including stainless steel, provides excellent thermal conductivity, while the fourth metal pressure block applies sufficient pressure between the upper and lower electrode materials while reducing the internal cavity volume, ensuring that the electrochemical performance of the battery remains unaffected.

[0079] like Figure 9 As shown in this disclosure, the temperature-controlled in-situ battery module is used in conjunction with a temperature control system, which includes...

[0080] A thermocouple temperature sensor is provided at the heat-conducting housing 610. The thermocouple temperature sensor is used to collect the temperature at the heat-conducting housing 610 and send it to a temperature controller.

[0081] A semiconductor cooling chip is disposed on the heat-conducting housing 610, and the cold end of the semiconductor cooling chip is attached to the outer wall of the heat-conducting housing 610.

[0082] A heat exchanger is installed at the hot end of a semiconductor cooling chip, and a cooling medium is circulated within the heat exchanger via a circulating pump.

[0083] The temperature controller is used to control the temperature at the heat-conducting housing 610 based on the measured temperature and set temperature collected by the thermocouple temperature sensor, and by controlling the semiconductor cooling chip and the circulating pump.

[0084] In cooling mode, the temperature control system activates a circulating pump to allow the cooling medium to flow through a heat exchanger attached to the hot end of the thermoelectric cooler, continuously removing heat. A temperature controller dynamically adjusts the current to the thermoelectric cooler for precise cooling. When heating is required, the circulating pump is shut off, and the temperature controller reverses the current flow to the thermoelectric cooler, switching its function from cooling to heating, thus achieving closed-loop temperature control. For investigating the properties of electrode materials at different temperatures, the temperature control module can attach a thermoelectric cooler or electric heating plate to a self-designed and developed temperature-controlled battery mold, using a circulating pump or thermocouple to regulate the temperature, enabling rapid imaging detection and analysis from a minimum of -30 degrees Celsius to a maximum of 60 degrees Celsius.

[0085] like Figure 10 As shown, in this disclosure, the optical imaging system includes a light source 130, a beam splitter 145, an objective lens 150, and a CCD camera 170. The light source 130 is used to generate incident light and transmit it to the electrode of the battery under test through the beam splitter 145 and the objective lens 150. The CCD camera 170 is used to collect the scattered light and reflected light from the glass substrate at the electrode of the battery under test transmitted back through the beam splitter 145.

[0086] In this disclosure, the incident light generated by the light source 130 is weakly coherent light with a wavelength of 660nm. Between the light source 130 and the beam splitter 145, a 4F optical system 141 consisting of two lenses, a pinhole aperture 142, a collimating lens 143, and a converging lens 144 are arranged in sequence.

[0087] The light source 130 disclosed herein may include a weakly coherent LED to reduce the influence of advanced interference rings and obtain higher imaging quality. In order to reduce the influence of beam energy on the battery electrode sample under test, a longer wavelength of 660 nm is selected, which can minimize the photothermal effect and photochemical damage to sensitive battery materials (especially in the electrolyte environment) and ensure that the observation process does not affect the electrochemical behavior of the material itself. The selection of the light source wavelength can also be varied according to the characteristics of the sample under test. After a series of beam processing components, the beam emitted by the light source 130 is processed and then incident on the glass substrate of the in-situ battery module in the form of parallel light through the objective lens, ensuring that the light spot irradiated on the sample is uniform and collimated parallel light. After that, the incident light is reflected by the upper surface of the glass substrate and used as reference light. The incident light hits the sample particles and excites sample scattered light. The two beams interfere and superimpose and are incident on the camera photosensitive plane through the imaging lens.

[0088] The 4f system 141, composed of two lenses, corrects the diverging beam emitted from the light source 130, while accurately transmitting the intensity distribution on the surface of the light source 130 to the output surface, thus "purifying" and "shaping" the beam. The pinhole aperture 142 filters out high-frequency noise and stray light introduced by uneven LED light emission points or lens edge aberrations, allowing only the central portion with the most uniform energy and flattest wavefront to pass through. The collimating lens 143 and converging lens 144 ensure that the beam is incident on the back focal plane of the objective lens 150 in an ideal state. This series of precise beam processing operations together ensure that the light field illuminating the battery electrode sample under test is highly uniform and collimated parallel light, minimizing optical aberrations and providing a clean background for the detection of weak ion dynamics signals.

[0089] The specific optical path for interference scattering microscopy in this embodiment is as follows: an LED is selected as the light source 130 to reduce the influence of higher-order interference rings and obtain higher imaging quality. To reduce the influence of beam energy on the sample, a longer wavelength of 660nm is selected. The diverging light emitted by the light source is corrected by a 4f system 141 consisting of two 40mm focal length lenses. After passing through a small aperture 142 to select a relatively uniform small area in the beam, it is collimated by a 50mm focal length lens and then converged by a 300mm focal length lens through a beam splitter 145 to the back focal plane of the objective lens 150. The objective lens 150 then incident the sample slide as parallel light. After this, the incident light is reflected by the upper surface of the glass substrate and used as reference light. The incident light hits the sample particles and excites sample scattered light. The two beams interfere and superimpose, and then are incident on the photosensitive plane of the CCD camera through an imaging lens 160 with a focal length of 500mm, completing the imaging.

[0090] like Figure 11 As shown, the light source 130 in this disclosure can also be a laser light source. A lens, a scattering sheet, a fiber optic coupler, an optical fiber, a pinhole aperture 142, a collimating lens 143, and a converging lens 144 are sequentially arranged between the light source 130 and the beam splitter 145. To reduce speckle caused by interference between the optical elements and the battery electrode surface, a high-speed motor drives a glass scattering sheet to scatter the laser light, reducing its spatial coherence while maintaining temporal coherence. The scattered laser light passes through a beam processing assembly and then through an objective lens, incident on the glass substrate of the in-situ battery module as parallel light, ensuring that the light spot irradiating the sample is uniform.

[0091] In a practical optical imaging system, a front-mounted mirror of the beam splitter 145 reflects the light path, facilitating adjustment of the beam's exit angle. A rear-mounted mirror of the beam splitter 145 reflects the light to the back focal plane of the vertically positioned objective lens 150, which uses a 100x magnification oil immersion lens for better imaging. The in-situ battery module is fixed on the sample stage 110 for placement. During testing, the battery integrated tester is connected to the in-situ battery module via alligator clips to provide the electrical signal stimulation required for battery operation.

[0092] In this disclosure, the in-situ battery module is located at a three-dimensional displacement platform 120.

[0093] The three-dimensional displacement platform includes an XYZ three-axis stepper motor and a Z-axis piezoelectric controller. The XYZ three-axis stepper motor has a large stroke and micron-level position control capability. The Z-axis piezoelectric controller, also known as a Z-axis high-precision piezoelectric displacement driver, has a 20μm stroke and a resolution as low as 1nm. Together, they can perform high-precision, large-range scanning of the position of the in-situ battery module.

[0094] This disclosure also provides an in-situ optical cell characterization method. The method uses the above-mentioned in-situ optical cell characterization device to acquire optical image sequences of electrode particles during the operation of the battery electrode sheet under test, and realizes in-situ characterization of the battery electrode sheet under test based on the processing of the image sequence.

[0095] Furthermore, this disclosure also provides a method for acquiring optical image sequences of electrode particles, which includes, when acquiring optical image sequences of electrode particles at the electrode sheet of the battery under test in an in-situ battery module located on a three-dimensional displacement platform 120 using an optical imaging system, the method comprises,

[0096] Establish a set of scanning path points for the 3D displacement platform 120;

[0097] The three-dimensional displacement platform 120 is driven to move point by point to each scanning path point in the set of scanning path points in sequence, and a target spatial database is constructed based on the identification of the target electrode particles;

[0098] Set the number of iterations, perform traversal imaging of all target electrode particles in the target spatial database, and construct an optical image sequence of all target electrode particles.

[0099] Based on the above, by controlling the position of the in-situ battery module, multiple particles from the same battery unit can be collected, achieving the purpose of characterizing spatial heterogeneity and improving measurement efficiency. It is understandable that the behavior of electrode materials on the macroscopic electrode sheet is not uniform; particles at different locations may exhibit different electrochemical activities (i.e., spatial heterogeneity). Traditional observation methods often only focus on individual particles, making it difficult to reflect this overall non-uniformity. By expanding the system's observation capabilities, multiple different single particles can be sequentially moved to the center of the field of view for observation in a single experiment, achieving multiple particle collection from the same battery unit and thus characterizing the spatial heterogeneity on the same electrode sheet.

[0100] Seen in Figure 14 This is a schematic diagram of 65 particle image sequences acquired simultaneously using the optical image sequence acquisition method for electrode particles disclosed herein.

[0101] In this disclosure, the expression for the set of scanned path points P is: ;

[0102] in, This represents the i-th scan path point in the set of scan path points P. , and Indicates scanning path points The x-axis displacement, y-axis displacement, and z-axis displacement.

[0103] In this disclosure, the driven three-dimensional displacement platform 120 moves sequentially point by point to each scanning path point in the set of scanning path points. Based on the identification of the target electrode particles, a target spatial database is constructed, including...

[0104] The three-dimensional displacement platform 120 moves to any scanning path point in the set of scanning path points and acquires the original image of the current field of view through the optical imaging system;

[0105] The system determines whether target electrode particles exist in the original image. If not, it controls the 3D displacement platform 120 to move to the next scanning path point. If they exist, the system uses the current order n of the target electrode particles as the corresponding target electrode particle number and the coordinates of the current scanning path point as the platform coordinates of the corresponding target electrode particle. And the image coordinates of the target electrode particles in the original image. As the image center coordinates of the corresponding target electrode particles;

[0106] The identification of all target electrode particles, number n, and platform coordinates. Image center coordinates and the corresponding target image Construct the target space database Q;

[0107] in, ;

[0108] in, This represents the nth data entry in the target spatial database Q.

[0109] This disclosure describes a method for integrating the serial numbers, initial platform coordinates, initial image center coordinates, and associated cropped images of all successfully identified target particles after traversing all predetermined locations, forming an initial target spatial database. By establishing this database and introducing visual feedback and motion compensation mechanisms in subsequent acquisition cycles, high-throughput, high-precision, and long-term stable automatic observation can be achieved. Specifically, a pre-scanning process is performed before the experiment officially begins to identify and record the initial spatial state of all target particles to construct the target spatial database, which improves the efficiency of subsequent data acquisition and correction.

[0110] In this disclosure, for any target electrode particle, the corresponding original image is cropped to obtain a sub-image region containing the corresponding target electrode particle, which is then used as the corresponding target image. ;

[0111] In this context, the image coordinates of the feature points or centroids of the target electrode particles in the original image are used as the corresponding image center coordinates. .

[0112] By cropping the original image, the amount of data can be reduced and the data can be simplified to avoid unnecessary waste of computing power. Then, the image coordinates of the feature points or centroids of the target electrode particles in the original image are recorded, and the serial number of the target particles and the coordinates of the image center are collected.

[0113] In this disclosure, the step of setting the number of iterations, traversing and imaging all target electrode particles in the target spatial database, and constructing an optical image sequence of all target electrode particles includes:

[0114] In a single traversal loop, all target electrode particles in the target spatial database Q are sequentially traversed and imaged.

[0115] For any target electrode particle, the target image acquired in each traversal cycle corresponds to that target electrode particle. This is an optical image sequence corresponding to the target electrode particles.

[0116] In this disclosure, traversal imaging of any target electrode particle within a single traversal cycle includes,

[0117] Retrieve the corresponding platform coordinates from the target space database Q. Control the three-dimensional displacement platform 120 to move to the corresponding position;

[0118] Based on planar position compensation, the x-axis compensation amount and y-axis compensation amount of the three-dimensional displacement platform 120 are obtained;

[0119] Based on focus compensation, the z-axis compensation amount of the three-dimensional displacement platform 120 is obtained;

[0120] Platform coordinates based on x-axis compensation, y-axis compensation, and z-axis compensation. Perform the update and control the 3D displacement platform 120 to move to the updated platform coordinates. At this location, complete the corresponding target image. The collection.

[0121] Through the above, planar position compensation can better correct the unique plane position of the in-situ battery module, and focus compensation can compensate for the regular directional movement of the battery during charging and discharging. In this disclosure, obtaining the x-axis and y-axis compensation amounts of the three-dimensional displacement platform 120 based on planar position compensation includes controlling the three-dimensional displacement platform 120 to move to the previous platform coordinates. At this point, focus compensation is performed to obtain the z-axis compensation amount of the three-dimensional displacement platform 120;

[0122] The z-axis offset of the three-dimensional displacement platform 120 is controlled based on the z-axis compensation amount;

[0123] Acquire the first raw image;

[0124] Based on the feature points or centroids of the target electrode particles, the image coordinates of the first original image and the corresponding image center coordinates The deviation is used to obtain the x-axis compensation amount. and y-axis compensation amount ;

[0125] Based on x-axis compensation amount and y-axis compensation amount Control the x-axis and y-axis offset of the three-dimensional displacement platform 120;

[0126] Acquire a second original image, and obtain the corresponding target image based on cropping of the second original image. .

[0127] By using a 3D displacement platform 120 for real-time detection and adjustment during the acquisition process, correction and image acquisition are performed synchronously. This allows for rapid resolution of any problems that arise, ensuring that the acquired original image sequence is clear and stable from the outset. This not only eliminates a significant amount of tedious post-processing data but, more importantly, ensures the integrity and continuity of long-term experimental data, providing indispensable technical support for studying slow-speed dynamic processes such as lithium-ion battery charging and discharging.

[0128] In this disclosure, focus compensation can be achieved based on an external calibration laser. Specifically, a calibration laser beam is emitted from a calibration laser source; the calibration laser beam reflected from the battery electrode sample under test is guided to an image acquisition camera to form a light spot through a feedback optical path set based on the external calibration laser; the displacement of the target particle in the optical image is calculated by analyzing the movement of the light spot using a computer, and reverse displacement compensation is calculated based on the displacement of the target particle.

[0129] This disclosure also enables focus compensation based on a gradient extremum focal length calibration algorithm. This achieves fully automatic, adaptive focal length maintenance, effectively improving the overall contrast and usability of the image sequence.

[0130] This disclosure also provides an in-situ optical cell characterization method, which uses the aforementioned optical image sequence acquisition method to acquire optical image sequences of electrode particles during the operation of the battery electrode under test; based on the processing of the optical image sequence, in-situ characterization of the battery electrode under test is achieved. This realizes fully automated and synchronized control from electrochemical stimulation to optical response acquisition, greatly improving the repeatability, reliability, and throughput of the experiment.

[0131] This disclosure also provides an in-situ optical characterization method for the dynamic process of a single battery particle, which includes:

[0132] Configure in-situ battery module;

[0133] During the operation of the in-situ battery module, the differential capacity curve, operating voltage and current curve, and optical image sequence of the electrode of the battery under test are collected.

[0134] Based on the differential capacity curve, working voltage and current curves, and optical image sequence at the electrode of the battery under test, dynamic in-situ optical characterization of electrode particles on the electrode of the battery under test in the in-situ battery module is completed.

[0135] Among them, the battery comprehensive tester can simulate the working process of the in-situ battery module and collect the differential capacity curve, working voltage and current curve of the in-situ battery module.

[0136] The optical image sequence of the battery electrode under test is acquired by an optical imaging system. The optical image sequence includes multiple electrode particle images of the electrode particles of the battery electrode under test arranged in time during one working cycle. The first electrode particle image in the optical image sequence corresponds to the electrode particle image of the battery electrode under test in the non-working state.

[0137] Among them, after acquiring the original optical image sequence of the electrode of the battery under test based on the optical imaging system, the optical image sequence is obtained by preprocessing and deep processing of the original optical image sequence.

[0138] The preprocessing of the original optical image sequence includes image stabilization processing of any original electrode particle image in the original optical image sequence based on a feature point matching algorithm.

[0139] In this disclosure, image stabilization processing is performed on any original electrode particle image in the original optical image sequence based on a feature point matching algorithm, including:

[0140] Feature points of each electrode particle image in the original optical image sequence are obtained based on the Hessian matrix; where the determinant expression of the Hessian matrix is, , As a scaling factor, it can be 0.9;

[0141] Based on the coordinate offset values ​​of the feature points between the corresponding original electrode particle image and the first electrode particle image, the corresponding original electrode particle image is translated to complete the image stabilization processing of any original electrode particle image based on the feature point matching algorithm.

[0142] Based on the above, the impact of experimental setup jitter during actual testing on the experimental results can be reduced, thus improving the accuracy of the results. Specifically, the feature point matching algorithm can employ, for example, an accelerated robust feature algorithm.

[0143] The deep processing performed on the original optical image sequence includes,

[0144] For any original electrode particle image, the original electrode particle image of the previous moment in the original optical image sequence is used as the reference frame, and the original electrode particle image is used as the detection frame to obtain the rolling differential image of the original electrode particle image. The rolling differential image corresponding to each original electrode particle image in the original optical image sequence is used as the optical image sequence.

[0145] This disclosure further extracts and enhances useful signals at the algorithmic level and eliminates residual mechanical jitter, ultimately yielding data suitable for precise quantitative analysis. Image signals contain a strong reference light background. The rolling difference algorithm, by differencing the current frame with the previous frame or the average frame within a time window, can significantly suppress invariant background noise, thereby highlighting minute optical contrast changes (such as refractive index and thickness changes) caused by ion embedding / extraction. This makes phase transition fronts (such as "contraction nuclei"), which were previously difficult to detect in the original image, clearly visible. On the other hand, despite real-time calibration, sub-pixel-level high-frequency jitter may still exist. The image stabilization algorithm calculates the global translation vector between frames by detecting the feature point matching relationship between each image and the reference frame, and performs inverse compensation. Through the processing of the optical image sequence by the data processing unit, the true dynamic signal of the sample is amplified and system noise is suppressed, significantly improving the signal-to-noise ratio and resolvability of the image sequence, laying a solid foundation for extracting accurate quantitative information (such as phase transition rate) from optical images.

[0146] The optical system imaging and SEM imaging comparison disclosed herein are as follows: Figure 13 As shown, Figure 13 For optical image acquisition effects, among which, Figure 13 A represents a comparison between the optical image and the SEM image. Figure 13 B represents the change of the optical image over time. Figure 13 The comparison between the imaging effect of the optical imaging system of this disclosure and the SEM effect is shown, demonstrating that the optical system of this disclosure has excellent ability to characterize single particles. Figure 13 B demonstrates the detection of the same particle for up to 220 hours, indicating that the optical system disclosed herein has high stability and can stably detect changes in single or multiple target particles with high sensitivity over long periods of time.

[0147] Seen in Figure 15 This is a schematic diagram illustrating the characterization of the lithium cobalt oxide phase transition process using an in-situ optical cell characterization method disclosed herein.

[0148] It is readily understood that those skilled in the art can combine, split, or reorganize the embodiments provided in this application to obtain other embodiments, all of which do not exceed the protection scope of this application.

[0149] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the embodiments shown are only part of the embodiments of the present invention. The actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for collecting optical image sequence of electrode particles, comprising, when collecting optical image sequence of electrode particle images at a to-be-tested battery electrode sheet of an in-situ battery module placed at a three-dimensional displacement platform (120) by using an optical imaging system, establishing a set of scanning path points of the three-dimensional displacement platform (120); driving the three-dimensional displacement platform (120) to move to each scanning path point in the set of scanning path points in sequence, and constructing a target space database based on identification of target electrode particles; setting a loop number, and performing traversal imaging on all target electrode particles in the target space database to construct an optical image sequence of all target electrode particles. The expression of the set of scanning path points P is The driving of the three-dimensional displacement platform (120) to move to each scanning path point in the set of scanning path points in sequence and the construction of the target space database based on the identification of target electrode particles comprise, acquiring an original image of a current field by the optical imaging system when the three-dimensional displacement platform (120) moves to any scanning path point in the set of scanning path points; 2. The method of collecting a sequence of optical images of electrode particles according to claim 1, characterized in that: The setting of the loop number and the traversal imaging on all target electrode particles in the target space database to construct the optical image sequence of all target electrode particles comprise, ； wherein, denotes the x-axis displacement amount, the y-axis displacement amount, and the z-axis displacement amount of the i-th scan path point in the scan path point set P. , and denotes the x-axis displacement amount, the y-axis displacement amount, and the z-axis displacement amount of the i-th scan path point in the scan path point set P. denotes the x-axis displacement amount, the y-axis displacement amount, and the z-axis displacement amount of the i-th scan path point in the scan path point set P.

3. The method of claim 1, wherein: performing traversal imaging on all target electrode particles in the target space database Q in sequence in a single traversal loop; The traversal imaging on any target electrode particle in a single traversal loop comprises, determining whether the target electrode particle exists in the original image, if not, controlling the three-dimensional displacement platform (120) to move to the next scanning path point, if so, taking the order n of the current target electrode particle as the number of the corresponding target electrode particle, taking the coordinates of the current scanning path point as the platform coordinates of the corresponding target electrode particle and taking the image coordinates of the target electrode particle in the original image as the image center coordinates of the corresponding target electrode particle; with the number n of all the target electrode particles recognized, platform coordinates , image center coordinates , and corresponding target images , a target space database Q is constructed; acquiring an x-axis compensation amount and a y-axis compensation amount of the three-dimensional displacement platform (120) based on plane position compensation; ； wherein, represents the nth data in the target space database Q.

4. The method of acquiring a sequence of optical images of electrode particles according to claim 3, characterized in that: For any target electrode particle, the corresponding original image is cropped to obtain a sub-image region containing the corresponding target electrode particle and taken as the corresponding target image ; wherein the image center coordinates of the target electrode particle are taken as the image coordinates of the feature point or the center of mass of the target electrode particle in the original image .

5. The method of claim 3, wherein: acquiring a z-axis compensation amount of the three-dimensional displacement platform (120) based on focus compensation; The acquisition of the x-axis compensation amount and the y-axis compensation amount of the three-dimensional displacement platform (120) based on the plane position compensation comprises, For any target electrode particle, the target image captured in each traversal cycle for the corresponding target electrode particle as a sequence of optical images of the corresponding target electrode particle.

6. The method of acquiring a sequence of optical images of electrode particles according to claim 5, characterized in that: controlling z-axis deviation of the three-dimensional displacement platform (120) based on the z-axis compensation amount; acquiring corresponding platform coordinates from a target space database Q controlling the three-dimensional displacement platform (120) to move to the corresponding position; acquiring a first original image; implementing focus compensation based on an additional calibration laser. Compensating the platform coordinate based on the x-axis compensation amount, the y-axis compensation amount and the z-axis compensation amount updating the platform coordinate, and controlling the three-dimensional displacement platform (120) to move to the updated platform coordinate where the corresponding target image is completed acquisition.

7. The method of claim 6, wherein: Implementing focus compensation based on a gradient extremum focal length calibration algorithm. Controlling the three-dimensional displacement platform (120) to move to the pre-update platform coordinates At this point, focus compensation is performed, and the z-axis compensation amount of the three-dimensional displacement platform (120) is obtained; The method for collecting optical image sequence of electrode particles according to any one of claims 1-9 is used to collect optical image sequence of electrode particle images in a working process of the to-be-tested battery electrode sheet. Based on processing of the optical image sequence, in-situ characterization of the to-be-tested battery electrode sheet is implemented. based on a deviation of a feature point or a center of mass of the target electrode particle in the first original image from a corresponding image center coordinate , an x-axis compensation amount and a y-axis compensation amount are obtained; Based on the x-axis compensation amount and the y-axis compensation amount , control the x-axis offset and the y-axis offset of the three-dimensional displacement platform (120); acquire a second original image, and acquire a corresponding target image based on cutting of the second original image .

8. The method of claim 6, wherein: ​ 9. The method of claim 6, wherein: ​ 10. In-situ optical battery characterization method, characterized in that: ​ ​

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