CN116068316B

CN116068316B - Application of chromatic aberration technology in detecting state of energy storage device

Info

Publication number: CN116068316B
Application number: CN202310088789.XA
Authority: CN
Inventors: 魏涛; 苏源惠
Original assignee: University of Jinan
Current assignee: University of Jinan
Priority date: 2023-02-03
Filing date: 2023-02-03
Publication date: 2023-09-29
Anticipated expiration: 2043-02-03
Also published as: CN116068316A

Abstract

The invention belongs to the technical field of detection of states of energy storage devices, and particularly relates to application of a chromatic aberration technology in detection of states of different parts of an energy storage device. The color difference technology is applied to detecting the state of the energy storage device, and an in-situ color test is carried out on any area of the energy storage device along with charge and discharge, a current collector and temperature change by using a color meter to obtain the color data change of the tested area of the energy storage device, so that the state change of any area of the energy storage device is evaluated by using the color difference technology. The detection method based on the color difference technology can intuitively and accurately verify the state change of the energy storage electrode material in the energy storage device in real time in the charge-discharge process, namely the provided color signal and the color difference change can accurately, quickly and in-situ reflect the charge-discharge state change of the energy storage electrode material, so that a new path is provided for the performance supervision and evaluation of the energy storage material in the energy storage device, and the detection method is a detection method with a very good application prospect.

Description

Application of chromatic aberration technology in detecting state of energy storage device

Technical Field

The invention belongs to the technical field of detection of states of energy storage devices, and particularly relates to application of a chromatic aberration technology in detection of states of different parts of an energy storage device.

Background

The development of socioeconomic and scientific technology has put higher demands on energy storage systems, and how to realize efficient and low-cost storage and conversion of energy into strategic support for promoting energy structure transformation and optimizing power production and consumption mode transformation is also one of research hotspots in the current energy storage field. Common and widely studied energy storage systems are lithium ion batteries, sodium ion batteries, nickel cadmium batteries, supercapacitors, and the like. Among them, the energy storage electrode material is a key for the use and development of energy storage systems, and is attracting attention. At present, besides the need of further exploring novel high-performance energy storage devices, the supervision, detection, evaluation and analysis of the operation of the energy storage devices are also key to realizing the efficient, rapid and stable development of the energy storage devices. There are still many worth of further exploring problems. On the one hand, it is difficult to maintain perfect electrical performance of these energy storage devices all the time, and after use, they often suffer from degradation, failure, etc. of components such as electrolytes, electrodes, etc., which means that their energy storage capacity is reduced. If the failure part of each component is positioned in time, the failure reason is eliminated, and the energy storage element with reduced performance can be timely and purposefully avoided or repaired; on the other hand, in order to develop thermal management test techniques and analytical models to study and monitor thermal behavior of lithium ion batteries and the like, it is necessary to face the problem that energy storage devices such as lithium ion batteries are prone to fire or explosion caused by overcharging, short-circuiting, thermal runaway and the like.

Over the past several decades, many approaches have been developed to explore the electrical performance, failure mechanisms, and safety issues of energy storage devices. Among them, electrical signal characterization is the most basic detection method and has been widely used to characterize its current, voltage, power, capacity, stability, etc. In addition, X-ray tomography and neutron scattering methods are used to characterize the internal structure of packaged commercial lithium batteries, and ultrasound imaging techniques are developed to study the wetting process and interface stability of the pouch cells. However, in view of the current trend of large-scale application of batteries and supercapacitors and increasing importance of people on safety problems, the detection technology cannot simultaneously and efficiently meet performance evaluation and thermal supervision of energy storage devices. Therefore, aiming at the demand of more accurate and safer energy storage equipment, it is necessary to explore a novel advanced technology of rapid, sensitive, economical, in-situ and nondestructive detection.

Disclosure of Invention

Aiming at the problems existing in the prior art, the invention aims to provide an application of a chromatic aberration technology in detecting the state of an energy storage device. The application can solve the defect that the existing test method can not test various states and performances of the energy storage device in real time and simultaneously.

In order to achieve the above purpose, the invention discloses the following technical scheme:

the color difference technology is applied to detecting the state of the energy storage device, and an in-situ color test is carried out on any area of the energy storage device along with charge and discharge, a current collector and temperature change by using a color meter to obtain the color data change of the tested area of the energy storage device, so that the state change of any area of the energy storage device is independently evaluated by using the color difference technology. The specific method adopted is as follows:

(1) Testing any portion of the energy storage device using a color meter;

(2) Recording the obtained color data, and realizing real-time nondestructive characterization of states of different components of the energy storage device by analyzing the change degree of the color data.

Further, the color meter may be a desk-top spectrocolorimeter, a hand-held spectrocolorimeter, an on-line spectrocolorimeter, a spectrophotometer (e.g., a spectrophotometer using a 0 °/45 ° measurement structure or a d/8 integrating sphere measurement structure, etc.), a photoelectric integrating colorimeter, a spectral scanning color difference meter, a digital image capturing method, a spectral imaging technique, etc., all of which utilize the same, similar or different principles to acquire a color data set.

Further, the energy storage device is an energy storage system with ion transfer or valence state transition. More preferably, the energy storage device with ion transfer or valence transition is a metal ion battery system, a negative ion battery system, aqueous and organic supercapacitors, nickel cadmium batteries, metal/sulfur batteries or flexible polymer energy storage device.

Further, the color data change of the tested area of the energy storage device is obtained, and the color change of different parts of the tested energy storage device is expressed and recorded in the form of numbers and the like by adopting a color standard; wherein the color standard is one or more of CIEXYZ, CIELAB, CIELUV, CIEUVW, YUV, HSL/HSV, RGB, CMYK and other color models.

The color difference data is data for quantifying the degree of change of color in a certain direction. The color difference data may be in the form of data based on any color model and obtained by any one of processing and calculation methods, and is not limited to a certain color difference formula. The color difference calculation formula may be a color difference formula specified by the CIE mechanism or may be a color difference formula specifically specified by the person based on the use requirement.

The invention detects the electric performance operation state of the energy storage device through the color signal and the color difference change, and simultaneously monitors the temperature of the energy storage device, which has important significance for realizing the efficient operation of the energy storage and conversion process of the energy storage device.

The states of the energy storage device comprise running/non-running states, voltage changes, capacity changes (one or more of stabilization, lifting, descending and failure), selection of different current collectors, changes of various related states such as component temperature changes and the like.

The invention can realize the detection content of the energy storage device through the application, and comprises the following steps:

(1) Real-time detection of the overall working and running states of all components of the energy storage device is realized, for example: determination of the operational/non-operational state, voltage change, capacity change (stabilization, lifting and attenuation);

(2) The method has the advantages that the energy storage device is independently evaluated at any position, and for example, the normal area, the performance attenuation area and the complete damage area existing on the energy storage material can be distinguished;

(3) The energy storage device is distinguished by using different materials as current collectors to change the colors of the electrode materials, and the influence of the current collectors on the electrical properties of the energy storage materials is independently evaluated by using color difference values.

(4) And in the non-operation and operation states, monitoring the temperature change of the energy storage device components such as the energy storage material, the shell, the diaphragm and the like, and realizing the monitoring of the heat correlation performance of the energy storage device.

The basic principle of the invention is as follows:

during the operation of the energy storage device, i.e. during the charging and discharging process, the material and the environment in which it is located are subject to continuous dynamic changes. For any electrode material and its environment, one or more of the following changes must occur during operation, including but not limited to: (1) embedding and extracting of carriers; (2) adsorption and desorption of carriers; (3) valence state change of the electrode material; (4) structural changes (e.g., crystal structure changes, crystal form transformations, crystal structure collapse, etc.) of the electrode material; (5) generating byproducts; (6) failure of the electrode material (breakage or fall-off of the electrode material, denaturation of the electrode material, etc.), and the like. Any one or more of these changes in temperature occur for all components of the energy storage device, which may result in a change in color of the electrode or other component.

By using a color meter, these colors and the degree of change in color can be accurately measured and calculated. Specifically, the colorimeter measures light source data, i.e., reflectance spectra, of the sample at each wavelength, which is then converted to color data based on a color model. The common color models are mainly CIEXYZ, CIELAB, CIELUV, CIEUVW, YUV, HSL/HSV, RGB, CMYK and the like. Further, the data may be compared and calculated in different color spaces, and theoretically, all color spaces and calculations for measuring the degree of color change are applicable to the present invention.

Compared with the prior art, the invention has the advantages that:

(1) The detection method based on the color difference technology can intuitively and accurately verify the state change of the energy storage electrode material in the energy storage device in real time in the charge-discharge process, namely the provided color signal and the color difference change can accurately, quickly and in-situ reflect the charge-discharge state change of the energy storage electrode material, thereby providing a new path for the performance supervision and evaluation of the energy storage material in the energy storage device, and being a detection method with very good application prospects;

(2) The detection method based on the color difference technology is suitable for various test conditions, can realize the detection of the overall state change of each component of the energy storage device, and can also realize the independent detection of the state change of any region of each component.

(3) The detection method based on the color difference technology can distinguish the color change of the current collectors of different materials selected by the energy storage device, and independently evaluate the influence of the current collectors on the electrical performance of the energy storage material according to the color difference value.

(4) The detection method based on the color difference technology can directly represent the temperature change of the energy storage material in the working/non-working state, thereby realizing the monitoring of the temperature change of the electrode material;

(5) The invention provides an in-situ color difference testing technology suitable for various complex conditions, and the detection method can synchronously realize the detection of the charge and discharge states of an energy storage device, the detection of the performance degradation/failure of any area of an electrode, the detection of the influence of different current collectors on the performance of the electrode and the detection of the temperature change of different components;

(6) The detection method has wide application range, and can be applied to ion transfer or valence state conversion energy storage devices such as metal (lithium, sodium, magnesium, aluminum and the like) ion battery systems, anion battery systems, water system and organic system super capacitors, nickel-cadmium batteries, metal (lithium, sodium, magnesium, aluminum and the like)/sulfur batteries, flexible polymer energy storage devices and the like;

(7) The detection method is suitable for various energy storage device structures such as button cells, soft package cells and the like, and has wide practical application prospect.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. Embodiments of the present invention are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is Ni (OH) obtained in example 1 ₂ A charge-discharge process curve of the electrode in a voltage range of 0-0.5V;

FIG. 2 is Ni (OH) obtained in example 1 ₂ A series of reflection spectra of the electrode during charge and discharge;

FIG. 3 is Ni (OH) obtained in example 1 ₂ X, Y, Z value of the electrode in the charge and discharge process changes along with the charge and discharge time;

FIG. 4 shows the Ni (OH) obtained in example 1 ₂ L of electrode in charge-discharge process ^* 、a ^* 、b ^* A change curve of the value along with the charge and discharge time;

FIG. 5 is a schematic diagram of a preferred embodiment of the present inventionExample 1 gives Ni (OH) ₂ L of electrode in charge-discharge process ^* 、u ^* 、v ^* A change curve of the value along with the charge and discharge time;

FIG. 6 shows the Ni (OH) obtained in example 1 ₂ ΔL of electrode in charge-discharge process ^* 、Δa ^* 、Δb ^* A change curve of the value along with the charge and discharge time;

FIG. 7 is a drawing of Ni (OH) obtained in example 1 ₂ ΔL of electrode in charge-discharge process ^* 、Δu ^* 、Δv ^* A change curve of the value along with the charge and discharge time;

FIG. 8 is a drawing of Ni (OH) obtained in example 1 ₂ Delta E of electrode ^* _ab Time profile and ΔE ^* _uv -a time-varying graph;

FIG. 9 shows the Ni (OH) obtained in example 1 ₂ Specific capacity of electrode-MAX (delta E ^* _ab ) A variation graph;

FIG. 10 is a graph showing the charge and discharge process of the graphite button cell obtained in example 2 in the voltage range of 0-2V;

FIG. 11 is a series of reflectance spectra of a graphite electrode of the graphite button cell obtained in example 2 during charge and discharge;

fig. 12 is a graph showing a change in X, Y, Z value with charge and discharge time of the graphite electrode of the graphite coin cell obtained in example 2 during charge and discharge;

FIG. 13 is L during charge and discharge of a graphite electrode of a graphite button cell obtained in example 2 ^* 、a ^* 、b ^* A change curve of the value along with the charge and discharge time;

FIG. 14 is L during charge and discharge of a graphite electrode of a graphite button cell obtained in example 2 ^* 、u ^* 、v ^* A change curve of the value along with the charge and discharge time;

FIG. 15 shows ΔL of graphite electrode of graphite button cell obtained in example 2 during charge and discharge ^* 、Δa ^* 、Δb ^* A change curve of the value along with the charge and discharge time;

FIG. 16 shows ΔL of graphite electrode of graphite button cell obtained in example 2 during charge and discharge ^* 、Δu ^* 、Δv ^* A change curve of the value along with the charge and discharge time;

FIG. 17 shows ΔE of graphite electrode of graphite button cell obtained in example 2 ^* _ab Time profile and ΔE ^* _uv -a time-varying graph;

FIG. 18 shows the specific capacity-MAX (. DELTA.E) of the graphite electrode of the graphite button cell obtained in example 2 ^* _ab ) A variation graph;

FIG. 19 is a graph showing the charge and discharge process of the lithium manganate button cell obtained in example 3 in the voltage range of 3-4.3V;

FIG. 20 is a series of reflectance spectra of a lithium manganate electrode of a lithium manganate button cell obtained in example 3 during charge and discharge;

fig. 21 is a graph showing a change in X, Y, Z value with charge and discharge time of a lithium manganate electrode of the lithium manganate coin cell obtained in example 3 during charge and discharge;

FIG. 22 is L of a lithium manganate electrode of example 3 obtained lithium manganate button cell during charge and discharge ^* 、a ^* 、b ^* A change curve of the value along with the charge and discharge time;

FIG. 23 shows ΔL of a lithium manganate electrode of example 3 obtained lithium manganate button cell during charge and discharge ^* 、Δa ^* 、Δb ^* A change curve of the value along with the charge and discharge time;

FIG. 24 shows ΔE of a lithium manganate electrode of a lithium manganate button cell obtained in example 3 ^* _ab -a time profile;

FIG. 25 is a graph showing the charge and discharge processes of the lithium cobaltate coin cell obtained in example 4 in the voltage range of 2.6-4.3V;

FIG. 26 shows the ΔE of a lithium cobalt oxide electrode of a lithium cobalt oxide coin cell obtained in example 4 ^* _ab -a time profile;

FIG. 27 is a graph showing the charge and discharge process of the lithium iron phosphate coin cell of example 5 over a voltage range of 2.6-3.6V;

FIG. 28 shows ΔE of lithium iron phosphate electrode of lithium iron phosphate button cell obtained in example 5 ^* _ab -time ofA variation graph;

FIG. 29 is a drawing of Ni (OH) obtained in example 6 ₂ Voltage change during 0-0.4V charge-discharge and delta E of normal discharge, partial failure and complete failure part of electrode ^* _ab -a time profile;

FIG. 30 is a graph of ΔE for different portions of an inoperable supercapacitor device obtained in example 7 ^* _ab -a temperature profile;

FIG. 31 shows the specific capacity-. DELTA.E of the supercapacitor device obtained in example 7 ^* _ab -a temperature profile;

FIG. 32 shows Ni (OH) in example 8 using nickel foam as a current collector ₂ L of electrode in charge-discharge process ^* 、a ^* 、b ^* A change curve of the value along with the charge and discharge time;

FIG. 33 shows the result of example 8, which shows Ni (OH) using carbon paper as a current collector ₂ L of electrode in charge-discharge process ^* 、a ^* 、b ^* A change curve of the value along with the charge and discharge time;

FIG. 34 is a drawing showing the result of example 8, ni (OH) with nickel foam as a current collector ₂ Charge-discharge process curve and delta E in voltage range of 0-0.6V of electrode ^* _ab -a time profile;

FIG. 35 is a drawing showing the result of example 8, wherein Ni (OH) was obtained using carbon paper as a current collector ₂ Charge-discharge process curve and delta E in voltage range of 0-0.6V of electrode ^* _ab -a time profile.

Detailed Description

The invention will be further described with reference to the accompanying drawings, it being understood that these examples are not limiting of the inventive content, but are merely illustrative. All modifications and equivalent substitutions to the technical proposal of the invention are included in the protection scope of the invention without departing from the spirit and scope of the technical proposal of the invention.

The reagents or materials used in the present invention may be purchased in conventional manners, and unless otherwise indicated, they may be used in conventional manners in the art or according to the product specifications. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present invention. The preferred methods, materials, and test instruments described herein are illustrative only. The invention will now be further described with reference to the drawings and specific examples.

The color difference technology refers to a method for obtaining a series of color and brightness data through a test sample, and then directly observing, comparing and analyzing the obtained data, or further calculating and processing the obtained data to obtain color difference data so as to accurately analyze the specific degree of color and brightness change. The test data showed consistent rules of variation for different samples, although there were differences in the values of intrinsic color and brightness.

Example 1

The embodiment provides a battery super capacitor material Ni (OH) by a chromatic aberration technology ₂ An application for detecting an operational state of a device, comprising the steps of:

ni (OH) ₂ The electrode material is prepared into a working electrode and is placed in a traditional three-electrode testing system, wherein in the three-electrode testing system, a saturated calomel electrode is used as a reference electrode, a platinum sheet is used as a counter electrode, and 2mol of the electrode material is used as a counter electrode ^-1 The KOH aqueous solution of (2) is an electrolyte.

Super capacitor electrode material Ni (OH) using a three electrode test system with a blue cell test system ₂ Constant current charge and discharge test is carried out, and simultaneously, a color meter is used for measuring Ni (OH) ₂ The electrode material portion of the electrode was tested for color difference variation. The data processing process is as follows:

(1) Testing Ni (OH) using a blue cell testing system ₂ Electrode at 3Ag ^-1 As a result of the change in voltage during charging and discharging, as shown in fig. 1, it can be seen that the voltage gradually increases to 0.6V as the charging process proceeds, and then gradually decreases to 0V as the discharging process proceeds. Measurement of Ni (OH) with a colorimeter ₂ The reflected light profile of the electrode at each wavelength during this process is shown in fig. 2.

(2) The reflected light curve was converted to CIEXYZ tristimulus values using the instrument by equation (1):

where λ is the wavelength of the equivalent monochromatic light. R (λ) and s (λ) are the reflected light spectrum of the sample and the relative spectral power distribution of the light source, respectively.And->Are CIE tristimulus values x, y, and z derived from CIE standard observers. Ni (OH) ₂ The X, Y, Z values of the electrodes during charge and discharge are shown in fig. 3. It can be seen that as the charging process proceeds, the charge is induced in Ni (OH) ₂ The voltage of the electrode is gradually reduced to a minimum value at X, Y, Z while the voltage of the electrode is increased from 0V to 0.6V; then as the discharge process proceeds, i.e. at Ni (OH) ₂ The X, Y, Z value gradually increases from the minimum value back to the initial level as the electrode voltage decreases from 0.6V to 0V. The voltage change trend and X, Y, Z value change trend in the whole charge and discharge process show corresponding consistent and opposite changes, which indicates that the X, Y, Z value change can well reflect the voltage change.

(3) After obtaining the X, Y, Z tristimulus values, the tristimulus values can be converted into CIELAB, CIELUV, RGB and CMYK color space data through a formula. Based on these color space data, only further processing of X, Y, Z values, they can also reflect changes in voltage, such as:

converting X, Y, Z tristimulus values into L of CIELAB color space by formulas (2) and (3) ^* 、a ^* And b ^* Data (L) ^* Has a value ranging from 0 to 100, a ^* And b ^* The range of values of (a) is-128 to +127):

where X, Y and Z are the tristimulus values of CIE XYZ of the sample. X is X _n 、Y _n And Z _n Is the normalized CIE XYZ tristimulus value of the reference white point (X under the use of D65 illuminant _n 、Y _n And Z _n Values 95.047, 100 and 108.883 respectively). L of the sample is obtained by taking the charge-discharge time as the abscissa ^* 、a ^* And b ^* Drawn into the same figure as shown in fig. 4. It can be seen that as the charging process proceeds, L ^* And b ^* Gradually decreases until it reaches a minimum value, and then gradually increases back to the initial level as the discharge process proceeds, which process corresponds well to the reverse direction of the trend of the change in the voltage value of the charge and discharge in fig. 1. a, a ^* The value change is small.

The X, Y, Z tristimulus values can also be converted to the CIELUV color space by the formula, which is also a color space that is easily converted from the CIEXYZ color space:

y is the tristimulus value of the color sample, Y _n Is the tristimulus value of the complete diffuse reflector, u' _n And v' _n Is a fully diffuse reflector chromaticity coordinate. (u ', v') is the coordinates of the unified chromaticity diagram of CIELUV (CIE 1976 UCS), and the equations for u 'and v' are as follows:

where x, y are chromaticity coordinates according to the 1931CIE standard observer and coordinate system. The results are shown in FIG. 5, by observing L ^* 、u ^* And v ^* Data change, the degree of change of the color of the sample is changed along with the change of the dataAnd a direct connection is established along with the charge and discharge process. During charging process, L ^* 、u ^* And v ^* The value gradually decreases until the value is reduced to the minimum value, and then gradually rises to return to the initial level along with the progress of the discharging process, and the process can also accurately correspond to the voltage value changing process of charging and discharging.

(4) In addition, the color data of different color spaces can be calculated and converted to obtain the specific variation degree of the color data in a certain direction. Examples of calculations and conversions are provided below:

for the CIELAB color space, a ^* Degree of change of valueb ^* Degree of change of valueL ^* Degree of change of value->The results are shown in FIG. 6. As the charging time progresses, Δl ^* And Deltab ^* The values gradually decrease, and then reach the lowest point at the time when the charging is finished; immediately following, as the discharge process proceeds, Δl ^* 、Δb ^* The values all gradually rose and returned to the original level. a, a ^* The value change is small.

For the CIELUV color space, u ^* Degree of change of valuev ^* Degree of change of valueL ^* Degree of change of value->The results are shown in FIG. 7. As the charging time progresses, Δl ^* 、Δu ^* And Deltav ^* The values gradually decrease, and then reach the lowest point at the time when the charging is finished; immediately following, as the discharge process proceeds, Δl ^* 、Δu ^* And Deltav ^* The values all gradually rose and returned to the original level.

In addition, there are some formulas for calculating color difference, which may be color difference formulas specified by CIE mechanism, or color difference formulas specifically specified by human being based on usage needs, for example: for the CIELAB color space, the change in color difference can be calculated by equation (6):

for the CIELUV color space, the change in color difference can be calculated by equation (7):

the results are shown in FIG. 8. It can be seen that the light source is,and->All rise along with the rise of the voltage and fall along with the fall of the voltage, and the voltage change trend can be well reflected. />And->The trend of (a) corresponds exactly to the trend of the voltage.

(5) At 7Ag ^-1 Is equivalent to Ni (OH) at the current density of (C) ₂ The electrode is subjected to a cyclic charge and discharge test and a color test, the value of the discharge specific capacity of each cycle in the cyclic charge and discharge process is calculated, and N in the process is extractedi(OH) ₂ Maximum value of color change of electrode material at each cycleThe results are shown in FIG. 9. Ni (OH) can be seen ₂ The specific discharge capacity of the electrode material tends to decrease gradually as the charge-discharge cycle progresses. In this process, the trend of the maximum value of the chromatic aberration is completely consistent with it, and also shows a decreasing trend.

The above results show that the obtained color change value can effectively and intuitively reflect the voltage change and the capacity change in the charge and discharge process in real time by testing the color data of the energy storage material or further processing the obtained color data. The various physical quantities (e.g., X, Y, Z, L, a, b, etc.) of the various color spaces may reflect the trend of the electrical signals of voltage, current, power, capacity, etc. of the electrode material to varying degrees.

Example 2

The embodiment provides an application example for detecting the running state of a graphite cathode of a lithium battery in real time by a chromatic aberration technology, which comprises the following steps:

preparing graphite electrode materials into a lithium ion battery negative electrode plate according to a conventional method, then using the lithium plate as a counter electrode according to the conventional method, and assembling the button battery in a glove box. For convenient observation, a hole with the diameter of 8mm is drilled on one side of the graphite electrode material of the button cell, and the button cell is sealed by optical glass.

And (3) performing charge and discharge tests on the button cell under the 0.6C multiplying power by using a blue electric cell test system, and simultaneously testing the graphite electrode material part of the button cell by using a color meter through a perforated electrode shell. The data processing process is as follows:

(1) The change of the voltage of the graphite coin cell battery during the charge and discharge was tested using the blue cell test system, and as shown in fig. 10, it can be seen that the voltage gradually increased to 2V as the charge process progressed, and then gradually decreased to 0V as the discharge process progressed. The reflected light curves of the graphite electrode at each wavelength during this process were also measured using a colorimeter, as shown in fig. 11.

(2) The reflected light curve is converted into CIEXYZ tristimulus values by using an instrument through a formula (1), and X, Y, Z values of the graphite button cell in the charge and discharge processes are shown in fig. 12. It can be seen that as the charging process proceeds, the voltage of the graphite coin cell gradually increases from 0V to 2V while its X, Y, Z value gradually increases to a maximum value; then as the discharge process proceeds, i.e., as the voltage of the graphite electrode drops from 2V to 0V, the X, Y, Z value gradually drops from the minimum value back to the initial level. The voltage change trend and X, Y, Z value change trend in the whole charge and discharge process show corresponding consistent change rules, which shows that the change of X, Y, Z value can well reflect the change of voltage.

(3) After obtaining the X, Y, Z tristimulus values, the X, Y, Z tristimulus values are converted to L of the CIELAB color space by formulas (2) and (3) ^* 、a ^* And b ^* Data as shown in fig. 13. It can be seen that for graphite button cells, L ^* 、a ^* And b ^* The data can also well reflect the change trend of the voltage. As the charging process proceeds, L ^* 、a ^* And b ^* Gradually rising to a maximum value and then gradually falling back to an initial level as the discharge process proceeds, which process corresponds well to the trend of the change in the voltage value of the charge and discharge in fig. 1. Notably, wherein L ^* 、a ^* And b ^* Varying degrees of b are slightly less, but show a consistent upward and downward trend.

After obtaining the XYZ tristimulus values, the XYZ tristimulus values are also converted into L of the CIELUV color space by formulas (4) and (5) ^* 、u ^* And v ^* Data, as shown in fig. 14. It can be seen that for graphite button cells, L ^* 、u ^* And v ^* The data can also well reflect the change trend of the voltage. As the charging process proceeds, L ^* 、u ^* And v ^* Gradually rising to a maximum value and then gradually falling back to the original level as the discharge process proceeds, which process is well suited to the process of FIG. 1The trend of the change of the voltage value of the charge and discharge corresponds.

for the CIELAB color space, Δl ^* 、Δa ^* And Deltab ^* The value changes are shown in fig. 15. It can be seen that as the charging process proceeds, Δl ^* 、Δa ^* And Deltab ^* The values are gradually increased, and then the highest point is reached at the time when the charging is finished; immediately following, as the discharge process proceeds, Δl ^* 、Δa ^* And Deltab ^* The values all gradually decreased and returned to the original level. For the CIELUV color space, ΔL ^* 、Δu ^* And Deltav ^* The result of the value change is shown in fig. 16. As the charging time progresses, Δl ^* 、Δu ^* And Deltav ^* The values are gradually increased, and then the highest point is reached at the time when the charging is finished; immediately following, as the discharge process proceeds, Δl ^* 、Δu ^* And Deltav ^* The values all gradually decreased and returned to the original level.

The color difference calculation is performed on the data of the CIELAB color space and the CIELUV color space by formulas (6) and (7), respectively, and the result is shown in fig. 17. It can be seen that the light source is,and->All rise along with the rise of the voltage and fall along with the fall of the voltage, and the voltage change trend can be well reflected. />And->The trend of (a) corresponds exactly to the trend of the voltage.

(5) The graphite button cell was subjected to a cyclic charge-discharge test while the graphite electrode was subjected to a color test, the value of the specific discharge capacity at each cycle during the cyclic charge-discharge was calculated, and the maximum value of the color change (i.e., color difference) of the graphite electrode material at each cycle during the cycle was extracted, and the result was shown in fig. 18. It can be seen that the specific discharge capacity thereof gradually decreases as the charge-discharge cycle progresses. In this process, the trend of the maximum value of the chromatic aberration is completely consistent with it, and also shows a decreasing trend.

Example 3

The embodiment provides a method for preparing lithium manganate (LiMn) serving as a lithium battery electrode material by using a chromatic aberration technology ₂ O ₄ LMO) is applied to the detection of the running state, comprising the following steps:

preparing an LMO electrode material into an electrode sheet according to a conventional method, and then assembling the button cell in a glove box by taking a lithium sheet as a counter electrode according to the conventional method. For the convenience of observation, a hole of 8mm in diameter was made in one side of the electrode material of the button cell, and sealed with an optical glass.

And (3) performing charge and discharge tests on the LMO button cell under the 0.6C multiplying power by using a blue electric cell test system, and simultaneously testing the electrode material part of the assembled LMO button cell by using a color meter. The data processing process is as follows:

(1) The change in voltage of the LMO coin cell battery during charge and discharge was tested using a blue cell test system, and as shown in fig. 19, it can be seen that the voltage gradually increased to 4.3V as the charge process progressed, and then gradually decreased to 3V as the discharge process progressed. The reflected light curves of the LMO electrode at each wavelength during this process were also measured using a colorimeter, as shown in fig. 20.

(2) The reflected light curve is converted into CIEXYZ tristimulus values by using an instrument through a formula (1), and X, Y, Z values of the LMO button cell in the charge and discharge processes are shown in fig. 21. It can be seen that as the charging process proceeds, its X, Y, Z value gradually increases to a maximum value while the voltage increases from 3V to 4.3V; the X, Y, Z value then gradually drops from the maximum value back to the original level as the discharge process proceeds, i.e. as the voltage drops from 4.3V to 3V. The voltage change trend and X, Y, Z value change trend in the whole charge and discharge process show corresponding consistent changes, which indicates that the X, Y, Z value change can well reflect the voltage change.

(3) After obtaining the X, Y, Z tristimulus values, the X, Y, Z tristimulus values are converted to L of the CIELAB color space by formulas (2) and (3) ^* 、a ^* And b ^* Data, as shown in fig. 22. It can be seen that for LMO button cells, L ^* 、a ^* And b ^* The data can also better reflect the change trend of the voltage. As the charging process proceeds, L ^* Gradually rising to a maximum value and then gradually falling back to the initial level as the discharge process proceeds, which process corresponds well to the trend of the change in the voltage value of the charge and discharge in fig. 1. a, a ^* The value trend is equal to L ^* And is diametrically opposed to the trend of voltage variation. b ^* The degree of variation of (c) is slightly smaller.

(4) In addition, color data of different color spaces can be calculated and converted to obtain a specific degree of change of the color data in a certain direction. Examples of calculations and conversions are provided below:

for the CIELAB color space, Δl ^* 、Δa ^* And Deltab ^* The value changes are shown in fig. 23. It can be seen that as the charging process proceeds, Δl ^* The value gradually rises, and then reaches the highest point at the time when charging is finished; immediately following, as the discharge process proceeds, Δl ^* The values gradually drop and return to the original level. Δa ^* And Deltab ^* The value trend is equal to DeltaL ^* Diametrically opposite, but Δb ^* The degree of variation of (c) is slightly smaller. Wherein DeltaL ^* 、Δa ^* And Deltab ^* Varying degrees of variation, but show a consistent upward and downward trend. The color difference calculation is performed on the data of the CIELAB color space by the formula (6), and the result is shown in fig. 24. It can be seen that the light source is,the voltage change trend can be well reflected by rising along with the rising of the voltage and falling along with the falling of the voltage. />The trend of (2) corresponds exactly to the trend of the voltage.

Example 4

The embodiment provides a method for preparing lithium manganate (LiCoO) serving as an electrode material of a lithium battery by using a chromatic aberration technology ₂ LCO) includes the following steps:

preparing an LCO electrode material into an electrode sheet by a conventional method, and then assembling the button cell in a glove box by taking the lithium sheet as a counter electrode by the conventional method. For the convenience of observation, a hole of 8mm in diameter was made in one side of the electrode material of the button cell, and sealed with an optical glass.

And (3) performing charge and discharge tests on the LCO button cell under the 0.6C multiplying power by using a blue electric cell test system, and simultaneously testing the electrode material part of the assembled LCO button cell by using a color meter.

The voltage change result of the LCO coin cell during charging and discharging is shown in fig. 25, and it can be seen that the voltage gradually increases from 2.6V to 4.2V during charging and then gradually decreases to 2.6V during discharging. Simultaneously measuring a reflected light curve of the LCO electrode at each wavelength in the process by using a color meter, converting the reflected light curve into CIEXYZ tristimulus values by using the meter through a formula (1), and then converting the CIEXYZ tristimulus values into CIELAB color space data L by using the formula ^* 、a ^* And b ^* . The color difference calculation is performed on the data of the CIELAB color space by the formula (6), and the result is shown in fig. 26. It can be seen that the light source is,the voltage change trend can be well reflected by rising along with the rising of the voltage and falling along with the falling of the voltage.

Example 5

The embodiment provides a method for preparing lithium iron phosphate (LiFePO) serving as an electrode material of a lithium battery by using a chromatic aberration technology ₄ LFP), comprising the following steps:

preparing an LFP electrode material into an electrode sheet according to a conventional method, and then assembling the button cell in a glove box by taking a lithium sheet as a counter electrode according to the conventional method. For the convenience of observation, a hole of 8mm in diameter was made in one side of the electrode material of the button cell, and sealed with an optical glass.

And (3) performing charge and discharge tests on the LFP button cell under the 0.6C multiplying power by using a blue electric cell test system, and simultaneously testing the electrode material part of the assembled LFP button cell by using a color meter.

The voltage change result of the LFP coin cell during charging and discharging is shown in fig. 25, and it can be seen that the voltage gradually increases from 2.6V to 3.6V during charging and then gradually decreases to 2.6V during discharging. Simultaneously, a color meter is used for measuring the reflected light curve of the LFP electrode at each wavelength in the process, the reflected light curve is converted into CIEXYZ tristimulus values through a formula (1) by using the meter, and then the CIEXYZ tristimulus values are converted into CIELAB color space data L through the formula ^* 、a ^* And b ^* 。

The color difference calculation is performed on the data of the CIELAB color space by the formula (6), and the result is shown in fig. 28. It can be seen that the light source is,the voltage change trend can be well reflected by rising along with the rising of the voltage and falling along with the falling of the voltage.

Example 6

The application of detecting any area of the energy storage material through a chromatic aberration technology to distinguish a normal area, a performance attenuation area and a complete damage area comprises the following steps:

(1) Co (OH) that will have a normal region, a performance decay region, and a full damage region, respectively ₂ The composite electrode was placed in a three-electrode test system, wherein Co (OH) as described above was used ₂ The electrode is a working electrode, a saturated calomel electrode is used as a reference electrode, a platinum sheet is used as a counter electrode, and the electrolyte is 2mol L ^-1 Is a KOH aqueous solution of (C).

The blue electric battery test system is used for testing the electrode material at 2Ag ^-1 And the charge and discharge test is carried out under the current density of the electrode, in the process, the normal area, the performance attenuation area and the complete damage area of the electrode are respectively tested by using a color meter, and the voltage curve in the electrochemical test process of the composite electrode is obtained to correspond to the color change curves of different areas in the charge and discharge process, as shown in fig. 29.

It can be seen that for Co (OH) having both normal, performance decay and complete damage regions ₂ For the composite electrode, the voltage gradually increases to 0.45V as the charging process proceeds, and then gradually decreases to 0V as the discharging process proceeds. While the three areas vary too much in color. For the normal area, the color difference can reach 1.59 at most, and is higher than the other two areas in the whole charge and discharge process; the variation of the chromatic aberration of the performance attenuation area is lower than that of the normal area; the discoloration of the fully damaged area is substantially insignificant. The variation degree of the chromatic aberration can be well corresponding to the charge-discharge performance, and the normal area, the performance attenuation area and the complete damage area on the same electrode can be effectively distinguished.

Example 7

The embodiment provides an application example for detecting the color change of components of an energy storage device, such as a stainless steel shell, an electrode material, a diaphragm and the like, along with the temperature change by a color difference technology, which comprises the following steps:

(1) And (3) raising the ambient temperature, and carrying out color test on the stainless steel shell, the NiCo-LDH electrode material and the diaphragm in a non-operation state to obtain color change trends at different temperatures, as shown in figure 30. It can be seen that the color differences of the stainless steel shell, the NiCo-LDH electrode material and the diaphragm all rise obviously along with the rise of the temperature, which indicates that the color differences can well reflect the change of the temperature.

(2) The super capacitor device is assembled by using NiCo-LDH and active carbon as electrodes, potassium hydroxide as electrolyte and button battery shells. For the convenience of observation, a hole of 8mm in diameter was made in one side of the electrode material of the button cell, and sealed with an optical glass.

The super capacitor device was subjected to charge and discharge test, the NiCo-LDH electrode was subjected to color test, and then the ambient temperature was raised, and the capacity change and color change (color difference) of the device during the temperature rise were recorded) A trend of color change during the test at different temperatures was obtained as shown in fig. 31. With the rise of temperature, the capacity of the device gradually rises, and the color difference is formedAnd the temperature is gradually increased, so that the influence of the temperature change in the operation process of the device on the performance of the device can be well reflected by the chromatic aberration.

Example 8

The present embodiment provides an example of application of the chromatic aberration technique to detection of the operation states of energy storage devices using different current collectors, the research method of which is similar to that of example 1, wherein Ni (OH) ₂ The current collectors of the electrodes were nickel foam and carbon paper, respectively.

Ni (OH) using foam nickel and carbon paper as current collector ₂ L of electrode material in one charge-discharge cycle ^* 、a ^* And b ^* The value changes are shown in FIGS. 32 and 33, and it can be seen that L is the same for both ^* 、a ^* And b ^* The numerical values and the corresponding variation degrees are different, which means that the color difference technology can also well analyze the current collector selected by the energy storage device. L as the charge and discharge process proceeds ^* 、a ^* And b ^* The values all exhibit a consistent trend of rising followed by falling or a trend of falling followed by rising. Calculate it and further convert the data into color difference dataAs shown in FIGS. 34 and 35, as charging proceeds, the color difference of both is +.>All rise, with the progress of discharge, the color difference of both is +.>All decrease and show consistent change rules. This shows that the color data can well reflect the trend of the change in the electrical properties of the energy storage device despite the different current collectors. />

Claims

1. The application of the color difference technology in detecting the state of the energy storage device is characterized in that a color meter is used for carrying out in-situ color test on any area of the energy storage device along with charge and discharge, a current collector and temperature change, data processing is carried out, and color data change of the tested area of the energy storage device is obtained, so that the state change of any area of the energy storage device is evaluated by the color difference technology;

the data processing process comprises the following steps:

detecting a reflected light curve of the area at each wavelength during the state change by using the color meter;

converting the reflected light curve obtained in the step (1) into CIE tristimulus values X, Y and Z by using an instrument according to the following formula (1):

；

wherein, in the formula (1), lambda is the wavelength of equivalent monochromatic light; r (λ) and s (λ) are the reflected light spectrum of the sample and the relative spectral power distribution of the light source, respectively; x ̅ (λ), y ̅ (λ) and Z ̅ (λ) are CIE tristimulus values X, Y and Z derived by CIE standard observers;

(3) After the tristimulus values X, Y and Z are obtained, the tristimulus values X, Y and Z can be converted into CIELAB, CIELUV, CIEUVW, YUV, HSL/HSV, RGB or CMYK color space data;

the energy storage device is based on carrier transfer or element valence state conversion;

the state change is one or more of an operating/non-operating state, a voltage change, a capacity change, a current collector change, and a temperature change.

2. The use according to claim 1, wherein the color meter is a spectrocolorimeter, a spectrophotometric color meter, a photoelectric integral color meter, a spectroscanning color difference meter, a digital camera method or a spectral imaging technique.

3. The use of claim 1, wherein the method of obtaining a change in color data of the area to be tested of the energy storage device is to digitally express and record the color of the tested energy storage device using a color standard.

4. The use of claim 1, wherein the capacity change is one or more of a stabilization, a lifting, a lowering and a failure of capacity.

5. The use according to claim 1, characterized in that the current collector is changed to a different material as electrode current collector.

6. The use according to claim 1, wherein the change in temperature is a change in temperature of an electrode of the energy storage device or a different component of the electrolyte, which is detectable by this technique.

7. The use according to claim 1, wherein the detection of any area is such that the color difference technique allows independent electrical and/or thermal performance detection of any area of the electrodes, electrolytes and other components of the energy storage device.