Step recycling and reusing method and system for waste lithium ion batteries

Abstract

The invention relates to the technical field of waste battery recycling and reusing, and discloses a waste lithium ion battery cascade recycling and reusing method and system.The method comprises the steps that firstly, feature information of waste lithium ion batteries is collected, grading is conducted according to the aging degrees of the batteries, differentiated discharging schemes are designed according to different grades, and discharging is conducted according to the different grades; obtaining first discharge data through precise self-adaptive discharge; and disassembling the waste battery, and determining a corresponding recycling scheme according to characteristic grading of the positive and negative electrode materials to obtain regenerated positive and negative electrode materials. Preparing a new battery by utilizing the regenerated material, testing to obtain second discharge data, and comparing the second discharge data with the first discharge data to evaluate the feasibility of recycling the waste battery; according to the method, the integrated treatment of grading diagnosis, cascade discharge and customized recovery can be realized according to the differentiation characteristics of the waste batteries and materials, the residual value of the batteries is excavated to the maximum extent, and the resource utilization level of the waste batteries is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste battery recovery and reuse, and more specifically, to a method and system for cascade recovery and reuse of waste lithium-ion batteries. Background Art

[0002] With the rapid development of the electric vehicle industry, the production and usage of lithium-ion batteries, as the core components of new energy vehicles, continue to grow rapidly. However, the service life of lithium-ion batteries is generally 3-8 years, and the generation of a large number of waste lithium-ion batteries poses a serious threat to resources and the environment. How to efficiently and economically recycle waste lithium-ion batteries and achieve sustainable use of resources is an important issue that needs to be solved urgently.

[0003] A Chinese patent with the authorization announcement number CN110176647B discloses a method for the cascade utilization of waste lithium-ion battery negative electrode materials. This method uses the inverse relationship between the capacity retention rate and the percentage of non-water-soluble lithium in the graphite negative electrode to the total lithium as the classification basis, designs different recycling processes according to the different capacity retention rates of lithium batteries, combines the electrochemical data such as the retention capacity obtained in the cascade recycling process of the battery cells, designs a cascade lithium extraction process for waste batteries with different degrees of aging, and uses pure water to extract Li from the negative electrode graphite of waste lithium batteries at room temperature to reduce the recycling cost and increase the reuse value. However, this method is mainly aimed at negative electrode materials, and does not involve the recycling of positive electrode materials, making it difficult to achieve efficient recovery of all components of waste lithium battery materials.

[0004] A Chinese patent with the authorization announcement number CN109346741B discloses a method for recycling waste positive electrode materials of lithium batteries. The method constructs a unique three-phase one-step reaction system, which can achieve a high one-step reaction leaching efficiency of cobalt, nickel, manganese and lithium for waste positive electrode materials of any composition. However, the method does not take into account the differences in the performance of waste batteries and materials, and uses the same treatment method for waste batteries and materials in different states, making it difficult to maximize the residual value of waste batteries.

[0005] In summary, the existing technology lacks a systematic and comprehensive integrated tiered recycling method for waste lithium batteries. It is difficult to carry out graded treatment according to the differences in waste batteries and material properties, and to achieve efficient recycling and high-value utilization of all component materials of waste batteries. Summary of the invention

[0006] In order to overcome the above-mentioned defects of the prior art, the present invention provides a method and system for the tiered recovery and reuse of waste lithium-ion batteries, which can realize the integrated processing of graded diagnosis, tiered discharge, and customized recovery according to the differentiated characteristics of waste batteries and materials, maximize the residual value of batteries, and improve the level of resource utilization of waste batteries.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] The cascade recovery and reuse methods of waste lithium-ion batteries include:

[0009] Collecting first characteristic information of waste lithium-ion batteries, dividing the waste lithium-ion batteries into different aging levels according to the first characteristic information, designing differentiated target discharge curves for batteries of each aging level, and performing precise adaptive discharge on the waste lithium-ion batteries of each aging level according to the differentiated target discharge curves to obtain first discharge data;

[0010] Disassembling the discharged waste lithium-ion batteries to obtain positive electrode materials and negative electrode materials, extracting second characteristic information of the positive electrode materials and the negative electrode materials, classifying the positive electrode materials and the negative electrode materials into different performance levels according to the second characteristic information, and determining a recycling scheme corresponding to each performance level; recycling and regenerating the positive electrode materials and the negative electrode materials of each performance level according to the recycling scheme to obtain a regenerated positive electrode material and a regenerated negative electrode material;

[0011] A new type of lithium-ion battery is prepared by using recycled positive electrode materials and recycled negative electrode materials, and a charge and discharge test is performed on the new type of lithium-ion battery to obtain second discharge data; the first discharge data is compared with the second discharge data to judge the feasibility of recycling the waste battery.

[0012] Furthermore, the first characteristic information includes a battery type parameter, a battery capacity parameter, a battery voltage parameter, and a battery usage time parameter;

[0013] The method of classifying the waste lithium-ion batteries into different aging levels according to the first characteristic information includes:

[0014] Based on the battery capacity parameters, calculate the capacity retention rate of waste lithium-ion batteries;

[0015] Based on the battery voltage parameters, the voltage decay rate of the waste lithium-ion battery is calculated;

[0016] Based on the battery usage time parameters, calculate the usage time coefficient of the waste lithium-ion battery;

[0017] The battery aging coefficient is calculated by combining the capacity retention rate, voltage decay rate and usage time coefficient. L , the aging levels of used lithium-ion batteries are classified into L1, L2, L3, and L4;

[0018] According to the battery aging coefficient θ L , the aging level classification of waste lithium-ion batteries includes:

[0019] When θ3≤θ LWhen ≤1, it is classified as L1 level, and θ3 is the third aging threshold;

[0020] When θ2≤θ L <θ3, it is classified as L2, and θ2 is the second aging threshold;

[0021] When θ1≤θ L <θ2, it is classified as L3, θ1 is the first aging threshold, θ3>θ2>θ1;

[0022] When 0<θ L When <θ1, it is classified as L4.

[0023] Further, the differentiated target discharge curves include an L1-level target discharge curve, an L2-level target discharge curve, an L3-level target discharge curve, and an L4-level target discharge curve;

[0024] The differentiated target discharge curves designed for each aging level of the battery include:

[0025] For L1 level batteries, a constant current discharge mode is used for discharge, the real-time voltage of the L1 level battery is marked as the first voltage, AM1 times the rated capacity is used as the discharge current, and the discharge is stopped when the first voltage drops to a preset first termination voltage, and the L1 level target discharge curve is obtained;

[0026] For L2 level batteries, a segmented constant current discharge method is adopted, and the real-time voltage of the L2 level battery is marked as the second voltage. First, AM2 times the rated capacity is used as the discharge current. When the second voltage drops to the first critical voltage, the current is automatically switched to AM3 times the rated capacity as the discharge current. When the second voltage drops to the preset second termination voltage, the discharge is stopped to obtain the L2 level target discharge curve; wherein, AM1>AM2>AM3;

[0027] For L3 level batteries, a two-stage discharge method of constant voltage and constant current is adopted. The real-time voltage of the L3 level battery is marked as the third voltage, and the real-time current of the L3 level battery is marked as the third current. The battery is discharged at a constant current first. When the third voltage drops to the second critical voltage, the battery is automatically switched to constant voltage discharge. When the third current drops to 0.05C, the discharge is stopped, and the target discharge curve of L3 level is obtained.

[0028] For L4 level batteries, pulse discharge is adopted for discharge, and the real-time voltage of the L4 level battery is marked as the fourth voltage. When the fourth voltage drops to the preset fourth termination voltage, the discharge is stopped to obtain the L4 level target discharge curve.

[0029] Further, the first discharge data includes a first discharge specific capacity C1, a first cycle life N1 and a first self-discharge rate S1;

[0030] The performing accurate adaptive discharge on waste lithium-ion batteries of various aging levels to obtain first discharge data includes:

[0031] According to the L1 target discharge curve, accurate adaptive discharge is performed on the L1 waste lithium-ion battery to obtain L1 discharge data, and the first discharge specific capacity, first cycle life and first self-discharge rate of the L1 battery are obtained according to the L1 discharge data;

[0032] According to the L2 target discharge curve, accurate adaptive discharge is performed on the L2 waste lithium-ion battery to obtain L2 discharge data, and the first discharge specific capacity, first cycle life and first self-discharge rate of the L2 battery are obtained according to the L2 discharge data;

[0033] According to the L3 target discharge curve, accurate adaptive discharge is performed on the L3 waste lithium-ion battery to obtain L3 discharge data, and the first discharge specific capacity, first cycle life and first self-discharge rate of the L3 battery are obtained according to the L3 discharge data;

[0034] According to the L4 target discharge curve, accurate adaptive discharge is performed on the L4 waste lithium-ion battery to obtain L4 discharge data, and the first discharge specific capacity, first cycle life and first self-discharge rate of the L4 battery are obtained according to the L4 discharge data;

[0035] The first discharge specific capacities of L1, L2, L3, and L4 level batteries are weighted averaged to obtain the first discharge specific capacity C1 in the overall first discharge data; the first cycle life of L1, L2, L3, and L4 level batteries are weighted averaged to obtain the first cycle life N1 in the overall first discharge data; the first self-discharge rates of L1, L2, L3, and L4 level batteries are weighted averaged to obtain the first self-discharge rate S1 in the overall first discharge data.

[0036] Furthermore, the second characteristic information includes material morphology information, material composition information and material structure information;

[0037] The method of classifying the positive electrode material and the negative electrode material into different performance levels according to the second characteristic information includes:

[0038] Based on the material morphology information, the morphology integrity index IM is calculated;

[0039] Based on the material composition information, the component retention index IC is calculated;

[0040] Based on the material structure information, the structural integrity index IS is calculated;

[0041] The material performance index IP is obtained by taking the weighted average of the morphology integrity index IM, the component retention index IC and the structural integrity index IS;

[0042] The cathode material and the anode material are classified into different performance levels according to the material performance index IP.

[0043] Furthermore, the classification of the cathode material and the anode material into different performance levels according to the material performance index IP includes:

[0044] When IP1 < IP ≤ 100%, it is classified as P1 level, where IP1 is the first performance threshold;

[0045] When IP2 < IP ≤ IP1, it is classified as P2 level, where IP2 is the second performance threshold and IP1 > IP2;

[0046] When 0 < IP ≤ IP2, it is classified as P3 level.

[0047] Furthermore, the second discharge data includes the second discharge specific capacity C2, the second cycle life N2, and the second self-discharge rate S2;

[0048] The comparison of the first discharge data with the second discharge data to evaluate the feasibility of recycling used batteries includes:

[0049] Compare the first discharge specific capacity C1 with the second discharge specific capacity C2, and calculate the capacity recovery rate η of the new lithium-ion battery C ; Compare the first cycle life N1 with the second cycle life N2, and calculate the cycle life improvement rate η of the new lithium-ion battery N ; Compare the first self-discharge rate S1 with the second self-discharge rate S2, and calculate the self-discharge control coefficient η of the new lithium-ion battery S ;

[0050] Comprehensively consider the capacity recovery rate η of the new lithium-ion battery C 、cycle life improvement rate η N and self-discharge control coefficient η S , calculate the performance evaluation index P of the new lithium-ion battery R ; Set the performance index threshold θ P , if P R ≥θ P , then it is determined that the recycling of used batteries is feasible.

[0051] A stepped recycling and reuse system for used lithium-ion batteries, which is used to implement the above-mentioned stepped recycling and reuse method for used lithium-ion batteries. The system includes:

[0052] An aging level classification module: used to collect the first characteristic information of the used lithium-ion battery, and classify the used lithium-ion battery into different aging levels according to the first characteristic information;

[0053] Discharge module: used to design differentiated target discharge curves for batteries of each aging level, and to perform precise adaptive discharge on waste lithium-ion batteries of each aging level according to the differentiated target discharge curves to obtain first discharge data;

[0054] Recycling module: used to disassemble the discharged waste lithium-ion batteries to obtain positive electrode materials and negative electrode materials, extract the second characteristic information of the positive electrode materials and the negative electrode materials, classify the positive electrode materials and the negative electrode materials into different performance levels according to the second characteristic information, and determine the recycling scheme corresponding to each performance level; according to the recycling scheme, recycle and regenerate the positive electrode materials and negative electrode materials of each performance level to obtain regenerated positive electrode materials and regenerated negative electrode materials;

[0055] Regeneration module: used to prepare new lithium-ion batteries using recycled positive electrode materials and recycled negative electrode materials;

[0056] Comparison module: used to perform charge and discharge tests on new lithium-ion batteries to obtain second discharge data; compare the first discharge data with the second discharge data to judge the feasibility of recycling used batteries.

[0057] An electronic device comprises a memory, a central processing unit and a computer program stored in the memory and executable on the central processing unit. When the central processing unit executes the computer program, the above-mentioned method for cascade recovery and reuse of waste lithium-ion batteries is implemented.

[0058] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed, implements the above-mentioned method for cascade recovery and reuse of waste lithium-ion batteries.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] The present invention proposes a fully integrated recycling and reuse scheme for waste lithium-ion batteries, which covers the entire closed-loop process from battery grading, adaptive discharge, disassembly, material recovery, and re-preparation, thus realizing the systematic and cascaded utilization of waste batteries; the battery aging characteristics are graded and treated, and differentiated optimal discharge schemes are designed for batteries with different aging degrees, so as to maximize the extraction of residual battery power and improve the residual value utilization rate; the performance of the recovered positive and negative electrode materials is graded and evaluated, and customized regeneration schemes are matched to ensure the performance of the recycled materials to the greatest extent, so as to realize the high-value utilization of the materials; the actual discharge performance of the new battery is used to match the The comparative evaluation of original batteries builds a quantifiable and evaluable basis for decision-making on the reuse of waste batteries, providing a feasibility demonstration method for the battery recycling industry; the integrated process opens up various links such as waste battery recycling, discharge, material extraction, and reuse, and realizes the efficient recycling of waste lithium-ion battery resources. It has significant environmental and economic benefits, and is of great significance to promoting the development of the battery recycling industry; the strategy of cascade discharge and differentiated utilization can fully tap the residual value of batteries with different degrees of aging and maximize resource utilization efficiency. Compared with the one-size-fits-all extensive recycling method, it can produce greater economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0062] Figure 1 The present invention is a flow chart showing the principle of the method for recycling and reusing waste lithium-ion batteries in stages;

[0063] Figure 2 A flow chart of a method for classifying waste lithium-ion batteries into different aging levels according to first characteristic information in the method for cascade recovery and reuse of waste lithium-ion batteries of the present invention;

[0064] Figure 3 A flow chart of a method for designing a differentiated target discharge curve in the method for cascade recovery and reuse of waste lithium-ion batteries of the present invention;

[0065] Figure 4 A flow chart of a method for obtaining first discharge data in the method for cascade recovery and reuse of waste lithium-ion batteries of the present invention;

[0066] Figure 5A flow chart of a method for classifying positive electrode materials and negative electrode materials into different performance levels according to second characteristic information in the method for cascade recovery and reuse of waste lithium-ion batteries of the present invention;

[0067] Figure 6 A flow chart of a method for comparing first discharge data with second discharge data to judge the feasibility of recycling the waste lithium-ion battery in the cascade recycling and reuse method of the present invention;

[0068] Figure 7 It is a functional module diagram of the waste lithium-ion battery cascade recovery and reuse system in the present invention. DETAILED DESCRIPTION

[0069] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0070] Example 1

[0071] See also Figure 1 As shown, this embodiment provides a method for recycling and reusing waste lithium-ion batteries in stages, including:

[0072] Step S1000, collecting first characteristic information of the waste lithium-ion batteries, dividing the waste lithium-ion batteries into different aging levels according to the first characteristic information, designing differentiated target discharge curves for batteries of each aging level, and performing precise adaptive discharge on the waste lithium-ion batteries of each aging level according to the differentiated target discharge curves to obtain first discharge data;

[0073] Furthermore, step S1000 includes:

[0074] Step S1100, receiving waste lithium-ion batteries to be processed, and collecting first characteristic information of the waste lithium-ion batteries, wherein the first characteristic information includes battery type parameters, battery capacity parameters, battery voltage parameters, and battery usage time parameters;

[0075] Specifically, step S1100 is to collect comprehensive information on waste lithium-ion batteries, laying the foundation for subsequent classification and processing. The battery type reflects the material system and structural characteristics of the battery. Common lithium-ion battery types include lithium iron phosphate batteries, ternary material batteries, lithium manganese oxide batteries, etc. Battery capacity is a key indicator for measuring the energy storage capacity of the battery, usually expressed in ampere-hours (Ah) or watt-hours (Wh). There are large differences in the material system, structural characteristics, and performance parameters of different types of batteries, so they need to be classified, identified, and processed. Battery capacity directly determines the battery's service life and mileage. The battery type and capacity information is quickly obtained through barcode or radio frequency identification technology, which is usually printed on the battery shell label. Use a professional voltage measuring instrument to measure the open circuit voltage and load voltage of the battery to obtain the battery voltage parameters; the open circuit voltage reflects the battery's state of charge, and the load voltage reflects the battery's output capacity. The two together determine the remaining power level of the battery. By consulting the usage records or process cards, the service life of the battery can be learned. The length of the usage time is often closely related to the degree of battery aging. By collecting characteristic information in multiple dimensions and parameters, the battery status can be evaluated from the perspectives of capacity, voltage, and usage time, and its potential value can be identified, so that policies can be tailored to the specific needs. The collection of this information requires the use of multiple means such as barcode scanning, radio frequency identification, voltage measurement, and data query. Data is obtained through a combination of automatic identification and manual entry to ensure that the information is comprehensive and accurate, providing a reliable basis for grading processing.

[0076] Step S1200, classifying the waste lithium-ion batteries into different aging levels according to the first characteristic information;

[0077] Furthermore, if Figure 2 As shown, step S1200 includes:

[0078] Step S1210, based on the battery capacity parameter, calculating the capacity retention rate of the waste lithium-ion battery as the first decision variable for aging grade classification;

[0079] Step S1220, based on the battery voltage parameter, calculating the voltage decay rate of the waste lithium-ion battery as a second decision variable for aging grade classification;

[0080] Step S1230, based on the battery usage time parameter, calculating the usage time coefficient of the waste lithium-ion battery as the third decision variable for aging level classification;

[0081] Step S1240, the battery aging coefficient is calculated by combining the capacity retention rate, the voltage decay rate and the usage time coefficient. L , the aging levels of used lithium-ion batteries are divided into L1, L2, L3, and L4.

[0082] When θ3≤θ L When ≤1, it is classified as L1, indicating that the battery is basically not aged and has good performance. θ3 is the third aging threshold;

[0083] When θ2≤θ L When <θ3, it is classified as L2, indicating that the battery is slightly aged but the performance is acceptable. θ2 is the second aging threshold.

[0084] When θ1≤θ L <θ2, it is classified as L3, indicating that the battery is moderately aged and the performance is significantly degraded. θ1 is the first aging threshold, and θ3>θ2>θ1;

[0085] When 0<θ L When <θ1, it is classified as L4, indicating that the battery is severely aged and the performance is seriously degraded.

[0086] Specifically, step S1200 is to classify the aging of the battery through quantitative analysis and comprehensive judgment based on the comprehensive collection of battery characteristic information. The capacity retention rate is equal to the ratio of the actual capacity to the initial capacity. It measures the degree of attenuation of the battery capacity relative to the initial state and is an intuitive reflection of the battery's health status. The higher the capacity retention rate, the smaller the capacity attenuation and the lighter the battery aging. The voltage decay rate is equal to the difference between the initial voltage and the actual voltage divided by the initial voltage, which reflects the performance degradation caused by battery aging from another perspective. The greater the voltage decay rate, the more serious the degradation of the battery active material, the greater the increase in internal resistance, and the more obvious the decrease in charging and discharging capacity. The use time coefficient is equal to the actual use time divided by the rated service life, which reflects the actual use intensity and aging risk of the battery. The longer the use time, the closer to or even more than the rated life, the higher the probability of aging failure of the battery. Finally, the three variables of capacity retention rate, voltage decay rate, and use time coefficient can be comprehensively judged by weighted summation to divide the battery into four levels. Among them, L1 batteries have excellent indicators, the least aging, and the highest residual value and cascade utilization potential; L2 and L3 are moderately aged and need further screening and repair; L4 is severely aged and cannot be used any longer, and can only be recycled. Through scientific aging classification, the battery status and value can be quickly identified, providing decision-making references for subsequent testing, repair, cascade utilization, material recycling and other links, improving disposal efficiency, extending the battery value chain, and achieving classified policies and precise utilization.

[0087] The calculation of the battery aging coefficient by combining the capacity retention rate, the voltage decay rate and the usage time coefficient includes:

[0088]

[0089] in:

[0090] Cr : Capacity retention rate. The higher the capacity retention rate, the lighter the battery aging;

[0091] V d : Voltage decay rate. The greater the voltage decay rate, the more serious the battery aging;

[0092] T u : Usage time coefficient. The longer the usage time, the higher the probability of battery aging;

[0093] α: Voltage attenuation rate influence coefficient, controls the voltage attenuation rate V d The sensitivity of the aging coefficient is as follows: the larger the α value, the greater the V d Small changes in will result in large changes in the aging coefficient;

[0094] β: Voltage decay rate threshold, indicating the critical point of voltage decay rate. d When it exceeds β, battery aging accelerates;

[0095] γ: The influence coefficient of the usage time coefficient, which controls the usage time coefficient T u The sensitivity of the aging coefficient is as follows: the larger the γ value, the higher the T u Small changes in will result in large changes in the aging coefficient;

[0096] δ: Use duration coefficient threshold, indicating the critical point of the use duration coefficient. u When δ is exceeded, the risk of battery aging increases significantly.

[0097] The general value range of α is between 1 and 10. This range can moderately adjust the impact of voltage decay rate on aging. If it is too small, it is insensitive, and if it is too large, it is too sensitive. The general value range of β is between 0.1 and 0.3. According to experience, when the voltage decay rate exceeds the range of 0.1-0.3, battery aging is significantly accelerated. The general value range of γ is between 1 and 10. Similar to α, this range can reasonably adjust the impact of usage time on aging. The general value range of δ is between 0.7 and 0.9. When the battery usage time exceeds 0.7 to 0.9 of the rated life, the aging risk increases significantly.

[0098] In this formula, the capacity retention rate C r When the L Increase, indicating that the battery is in a healthier state; voltage decay rate V d When the L Decrease, indicating that the battery is aging; the usage time coefficient T u When increasing: θ LDecrease indicates an increase in aging risk. The formula introduces exponential and square root operations to more comprehensively reflect the impact of various battery characteristics at different aging stages. Combining three different aging decision variables together, through nonlinear transformation, it can make a more accurate assessment of the battery status. Customized assessments of batteries of different types and usage environments can be performed by adjusting parameters α, β, γ, and δ.

[0099] Parameters α, β, γ, δ fitting process:

[0100] By collecting a large amount of experimental data and historical usage data of different batteries, these parameters can be fitted:

[0101] Data collection: Conduct tracking tests on batteries of different types and under different usage conditions, and record data such as capacity retention rate, voltage decay rate, and usage time.

[0102] Data cleaning: remove abnormal data points to ensure data quality.

[0103] Parameter initialization: Give initial guess values ​​for α, β, γ, and δ.

[0104] Loss function definition: Define a loss function, such as mean square error (MSE), to evaluate the effect of fitting parameters.

[0105] Optimization algorithm: Use an optimization algorithm (such as gradient descent) to iteratively update the parameters to minimize the loss function.

[0106] Cross-validation: Divide the data into training set and validation set to prevent overfitting.

[0107] Parameter determination: After obtaining the optimal parameter value, the final fitting is performed on the entire data.

[0108] Step S1300, designing a differentiated target discharge curve for each aging level of the battery; the differentiated target discharge curve includes an L1 level target discharge curve, an L2 level target discharge curve, an L3 level target discharge curve, and an L4 level target discharge curve;

[0109] Furthermore, if Figure 3 As shown, step S1300 includes:

[0110] Step S1310, for the L1 level battery, a constant current discharge mode is used for discharge, the real-time voltage of the L1 level battery is marked as a first voltage, AM1 times the rated capacity is used as the discharge current, and the discharge is stopped when the first voltage drops to a preset first termination voltage, so as to obtain an L1 level target discharge curve;

[0111] Step S1320, for the L2 level battery, a segmented constant current discharge mode is adopted, the real-time voltage of the L2 level battery is marked as the second voltage, AM2 times the rated capacity is first used as the discharge current, when the second voltage drops to the first critical voltage, the current is automatically switched, and AM3 times the rated capacity is used as the discharge current, and the discharge is stopped when the second voltage drops to the preset second termination voltage, and the L2 level target discharge curve is obtained; wherein, AM1>AM2>AM3;

[0112] Step S1330, for the L3 level battery, a constant voltage and constant current two-stage discharge mode is adopted, the real-time voltage of the L3 level battery is marked as the third voltage, the real-time current of the L3 level battery is marked as the third current, and the constant current is first discharged. When the third voltage drops to the second critical voltage, it is automatically converted to constant voltage discharge. When the third current drops to 0.05C, the discharge is stopped, and the L3 level target discharge curve is obtained;

[0113] Step S1340, for the L4 level battery, pulse discharge is used for discharge, the real-time voltage of the L4 level battery is marked as the fourth voltage, and the discharge is stopped when the fourth voltage drops to the preset fourth termination voltage, so as to obtain the L4 level target discharge curve.

[0114] Specifically, step S1300 is to design differentiated discharge plans and target curves for batteries of different aging levels based on a comprehensive assessment of the battery aging status. The core idea is to "take measures in accordance with the battery's characteristics". According to the differences in battery health conditions, corresponding discharge strategies are adopted to fully release the residual energy of the battery and improve resource utilization efficiency; at the same time, the battery aging caused by improper discharge methods should be avoided, resulting in irreversible damage. By matching reasonable discharge rates, switching mechanisms, termination conditions, etc., an accurate discharge model is constructed to generate differentiated target discharge curves to guide subsequent adaptive discharge control.

[0115] For L1 level batteries, due to their optimal health status, small capacity attenuation, and low internal resistance increase, they can withstand higher constant current discharge without causing significant capacity loss and life attenuation. Therefore, step S1310 adopts a constant current discharge mode, with AM1 times the rated capacity as the discharge current, which is equivalent to a higher rate of 0.5C, until the first voltage (i.e., the real-time voltage of the L1 level battery) drops to the first termination voltage (such as 2.5V) and stops discharging. In this way, while ensuring higher discharge efficiency and completeness of energy release, over-discharge of the battery caused by excessive discharge can be avoided. At the same time, the first voltage change curve is monitored and recorded in real time as a basis for evaluating the discharge characteristics of the L1 level battery, and is drawn into an L1 level target discharge curve for subsequent adaptive discharge process control.

[0116] For L2 level batteries, since they have been slightly aged, the capacity and voltage have declined, it is not appropriate to use a single constant current rate. In order to find a balance between efficient discharge and slowing down the attenuation, a segmented constant current discharge scheme is designed in step S1320. First, a lower AM2 times rated capacity is used as the discharge current, such as 0.3C. When the second voltage (i.e., the real-time voltage of the L2 level battery) drops to the first critical voltage (such as 3.0V), it is promptly switched to a lower AM3 rate (such as 0.2C) until the second voltage drops to the second termination voltage (such as 2.7V). By adjusting the current size in segments, that is, moderately increasing the current in a high power state to promote energy release; and reducing the current in a low power state to reduce the impact and damage of the voltage drop on the electrode material, the capacity attenuation can be delayed to the maximum extent while ensuring a certain discharge efficiency. At the same time, by recording the change curve of the second voltage during the segmented discharge process, the L2 level target discharge curve is obtained as the control basis for the adaptive segmented constant current discharge.

[0117] For L3 level batteries, their aging degree is further aggravated, and it is not advisable to continue constant current discharge. Step S1330 adopts a two-stage discharge mode of constant voltage and constant current. First, discharge at a smaller rate of constant current. When the third voltage (i.e., the real-time voltage of the L3 level battery) drops to the second critical voltage (such as 3.2V), switch to constant voltage mode in time. In the constant voltage stage, the control voltage is stabilized at 3.2V, and the change of the third current (i.e., the real-time current of the L3 level battery) is monitored. As the polarization of the battery intensifies, the current will gradually decrease. When it drops to a smaller value of 0.05C, it can be considered that the battery has basically been discharged, and the discharge is stopped at this time. The reason for choosing 0.05C as the termination condition is that the current is close to 0 at this time, the active material of the battery has tended to be exhausted, and it is no longer practical to continue discharging, and too small a current may induce dangers such as dendrites. Through the two-stage discharge of constant current first and constant voltage later, energy can be released as soon as possible when the battery is high, and then switched to constant voltage mode in the later stage, with small current discharge under stable voltage, and the residual capacity is fully utilized until the battery is stable; at the same time, the risks of overcharge and over-discharge are effectively avoided. In this way, the L3 target discharge curve is obtained to guide the automatic switching and precise control of the two-stage discharge.

[0118] As for L4 level batteries, their aging is very serious, and the capacity and voltage decay are huge. The traditional continuous constant current or constant voltage discharge is no longer applicable, which may cause safety hazards. Step S1340 adopts a pulse discharge mode, which reduces the continuous discharge stress and delays the battery decay through periodic short-term discharge and shelving. Control the pulse current to the fourth voltage (i.e., the real-time voltage of the L4 level battery) The decline is stopped when it drops to the fourth termination voltage (such as 2.0V), and the pulse discharge is performed again after standing for a period of time, and the cycle is repeated until the battery voltage stabilizes in a safe range. Make full use of the driving force generated during the pulse discharge process, intermittently promote the insertion and removal of residual lithium ions, and slowly release the remaining trace energy of the L4 level battery until the voltage tends to stabilize. By adjusting the pulse width and the standing time, the energy release rate and the charge and discharge stress can be flexibly controlled. While recovering as much energy as possible, the irreversible damage such as electrolyte drying and pole piece powdering caused by continuous discharge can be avoided. Thus, the L4 level target discharge curve is obtained, which is used to guide the automatic execution of pulse discharge.

[0119] In summary, steps S1310 to S1340 construct a comprehensive and systematic differentiated discharge scheme from multiple dimensions such as termination voltage, critical voltage, discharge rate, switching mechanism, and pulse parameters. The setting of termination voltage and critical voltage needs to take into account energy utilization and battery safety, and is usually determined according to the battery material system and aging characteristics. For example, for the ternary material system, it is recommended that the termination voltage be set to 2.5-2.7V and the critical voltage be set to 3.0-3.2V; for the lithium iron phosphate system, the termination voltage can be set to about 2.0V and the critical voltage can be set to 2.5-2.8V. The choice of discharge rate must consider both the battery tolerance and the discharge efficiency. For example, for L1 healthy batteries, a higher rate of more than 0.5C can be used, while L2 and L3 batteries should be reduced to below 0.3C; for highly aged L4 batteries, the pulse current may be reduced to below 0.1C. This way of optimizing the discharge plan in accordance with the individual characteristics of the battery can achieve precise control and optimal matching of the discharge process while respecting the individual differences of the battery, taking into account both resource recycling and battery health maintenance, and can maximize the residual value of the battery, laying the foundation for cascade utilization.

[0120] For example, assuming that the rated capacity of a ternary material battery is 2000mAh, its termination voltage can be set to 2.7V, the first critical voltage to 3.2V, and the second critical voltage to 3.0V. If it is determined to be in L1 healthy state, a constant current discharge of 0.5C can be used, that is, a constant current of 1000mA can be used to discharge to 2.7V; if it is determined to be L2 mild aging, a constant current of 600mA (0.3C) can be used to discharge to 3.2V, and then switch to a constant current of 400mA (0.2C) to 2.7V; if it is determined to be L3 moderate aging, a constant current of 400mA (0.2C) can be used to discharge to 3.0V, and then switch to a constant voltage discharge of 3.0V until the current drops to 100mA (0.05C); if it is determined to be L4 severe aging, a pulse current of 200mA (0.1C) can be used, discharging for 30 seconds each time, standing for 1 minute, and repeating this cycle until the voltage stabilizes below 2.0V. It can be seen that differentiated discharge schemes can fully consider the characteristics of different aged batteries, take targeted measures, and prescribe the right medicine to improve energy efficiency while maintaining battery health to the greatest extent, extending its remaining life, and creating favorable conditions for battery cascade utilization and green remanufacturing. This precise discharge method is not only technically feasible, but also economically effective, and has broad application prospects.

[0121] In the battery field, C is the unit of rated capacity of the battery. For example, if the capacity of a battery is 2000mAh, then 1C represents a current of 2000mA.

[0122] 0.3C and 0.2C indicate the ratio of discharge current to rated capacity:

[0123] 0.3C means the discharge current is 0.3 times the rated capacity. For example, if it is a 2000mAh battery, 0.3C means a discharge current of 600mA (2000mAh×0.3).

[0124] 0.2C means the discharge current is 0.2 times the rated capacity. Similarly, for a 2000mAh battery, 0.2C means a discharge current of 400mA (2000mAh×0.2).

[0125] Batteries of different capacity specifications have different allowable safe charging and discharging currents; the C rate can be used to uniformly describe the charging and discharging requirements of batteries of different capacities.

[0126] It is required that AM1>AM2>AM3. AM1, AM2 and AM3 correspond to the constant current discharge rates of L1 and L2 level batteries respectively. The reasons are as follows:

[0127] L1-level batteries are the batteries in the best health, with small capacity decay and low internal resistance increase. They can withstand higher discharge rates without causing significant capacity loss and life decay. Therefore, a relatively high AM1 rate (such as 0.5C) can be used for constant current discharge.

[0128] L2 batteries are slightly aged batteries, and their capacity and voltage have declined to a certain extent. If a high discharge rate is still used, the capacity loss may be aggravated and the remaining life may be shortened. Therefore, it is necessary to appropriately reduce the discharge rate and adopt a segmented constant current strategy. A lower AM2 rate (such as 0.3C) is used in the first half, and after the voltage drops to a certain critical value, it is further reduced to a lower AM3 rate (such as 0.2C). In this way, while ensuring a certain discharge efficiency, the impact and damage of the voltage drop on the electrode material can be reduced.

[0129] The design of AM1>AM2>AM3 is the result of seeking a balance between discharge efficiency and battery protection based on the consideration of battery health status. The higher the discharge rate, the higher the discharge efficiency, but the greater the stress on the battery, and the faster the aging rate. For batteries with different aging degrees, appropriately reducing the discharge rate can minimize the battery aging rate and maintain its residual value while ensuring the necessary energy release efficiency.

[0130] Step S1400, according to the differentiated target discharge curve, perform precise adaptive discharge on the waste lithium-ion batteries of each aging level to obtain first discharge data; the first discharge data includes a first discharge specific capacity C1, a first cycle life N1 and a first self-discharge rate S1.

[0131] Furthermore, if Figure 4 As shown, step S1400 includes:

[0132] Step S1410, performing precise adaptive discharge on the L1 level waste lithium ion battery according to the L1 level target discharge curve to obtain L1 level discharge data, and obtaining a first discharge specific capacity, a first cycle life, and a first self-discharge rate of the L1 level battery according to the L1 level discharge data;

[0133] Step S1420, performing precise adaptive discharge on the L2 level waste lithium ion battery according to the L2 level target discharge curve to obtain L2 level discharge data, and obtaining a first discharge specific capacity, a first cycle life, and a first self-discharge rate of the L2 level battery according to the L2 level discharge data;

[0134] Step S1430, performing precise adaptive discharge on the L3 level waste lithium-ion battery according to the L3 level target discharge curve to obtain L3 level discharge data, and obtaining a first discharge specific capacity, a first cycle life, and a first self-discharge rate of the L3 level battery according to the L3 level discharge data;

[0135] Step S1440, performing precise adaptive discharge on the L4 level waste lithium-ion battery according to the L4 level target discharge curve to obtain L4 level discharge data, and obtaining a first discharge specific capacity, a first cycle life, and a first self-discharge rate of the L4 level battery according to the L4 level discharge data;

[0136] Step S1450, weighted average the first discharge specific capacities of L1, L2, L3, and L4 level batteries to obtain the first discharge specific capacity in the overall first discharge data; weighted average the first cycle life of L1, L2, L3, and L4 level batteries to obtain the first cycle life in the overall first discharge data; weighted average the first self-discharge rates of L1, L2, L3, and L4 level batteries to obtain the first self-discharge rate in the overall first discharge data.

[0137] Specifically, the specific discharge capacity refers to the amount of electricity that can be discharged per unit mass or volume of a battery, and is an important indicator for evaluating the energy density of a battery. The unit is usually mAh / g or mAh / cm 3 . Cycle life refers to the number of times a battery can be repeatedly charged and discharged under specified conditions. The more cycles, the longer the battery life. Self-discharge refers to the capacity loss of the battery due to side reactions in the open circuit state. The self-discharge rate S is usually expressed as a percentage of capacity loss per unit time. The slower the self-discharge, the stronger the battery's charge retention ability.

[0138] Step S1400 implements precise and adaptive discharge control for batteries of different aging levels under the guidance of the target discharge curve. The core is to dynamically adjust the discharge strategy by real-time tracking of the discharge curve, so that the actual discharge process is as close as possible to the target discharge mode, and the residual energy is released to the maximum extent while discharging safely. According to the L1 target discharge curve, constant current adaptive discharge is performed on the L1 battery, and the first voltage change is monitored in real time. When the first voltage drops to the first termination voltage, the discharge is stopped, and the L1 discharge data such as discharge capacity, discharge time, voltage, and current are recorded; and the first discharge specific capacity, that is, the discharge capacity per unit mass or volume of the L1 battery, is calculated based on the L1 discharge data, in mAh / g or mAh / cm 3 By repeatedly charging and discharging at constant current and recording the number of cycles, the first cycle life data of the L1 battery is obtained. After standing for a period of time, such as 30 days, the degree of decrease in the open circuit voltage is measured to estimate the first self-discharge rate, that is, the percentage of loss of L1 battery capacity per unit time.

[0139] According to the L2 target discharge curve, perform segmented constant current adaptive discharge on the L2 battery, monitor the second voltage change in real time, automatically switch the current according to the first critical voltage, stop discharging when the second voltage drops to the second termination voltage, and record the L2 discharge data such as discharge capacity, discharge time, voltage, current and critical point data; calculate the first discharge specific capacity of the L2 battery based on the L2 discharge data. Obtain the first cycle life of the L2 battery through a limited number of segmented charge and discharge cycles, such as 200 times. Test the first self-discharge rate of the L2 battery at rest.

[0140] According to the L3 target discharge curve, perform constant voltage and constant current adaptive discharge on the L3 battery. First, perform constant current discharge, monitor the third voltage change in real time, and automatically switch to constant voltage discharge when the third voltage drops to the second critical voltage. Monitor the third current change in real time, stop discharging when the third current drops to 0.05C, and record the discharge capacity, discharge time, voltage, current and other L3 discharge data; Based on the L3 discharge data, evaluate the first discharge specific capacity of the L3 battery. Use a small current such as 0.1C for a small number of cycles such as 100 to roughly estimate the first cycle life of the L3 battery. Evaluate the first self-discharge rate of the L3 battery through a longer static experiment such as 60 days.

[0141] According to the L4 target discharge curve, pulse adaptive discharge is performed on the L4 battery. By setting the pulse width and intermittent time, short-term discharge and shelving are performed periodically, and the fourth voltage of the battery is monitored in real time until the fourth voltage stabilizes within a safe range (lower than the fourth termination voltage). Discharge is stopped and L4 discharge data such as discharge capacity, discharge time, number of pulses, and voltage waveform of the entire pulse discharge process are recorded; based on the L4 discharge data, the first discharge specific capacity of the L4 battery is analyzed. Considering that the L4 battery has been severely aged, the cycle life test can be omitted, and its first cycle life is recorded as 0. After a longer-term static experiment such as 90 days, the first self-discharge rate of the L4 battery is evaluated.

[0142] The first discharge specific capacities of L1, L2, L3, and L4 level batteries are weighted averaged to obtain the overall first discharge specific capacity; the first cycle life of L1, L2, L3, and L4 level batteries are weighted averaged to obtain the overall first cycle life; the first self-discharge rates of L1, L2, L3, and L4 level batteries are weighted averaged to obtain the overall first self-discharge rate.

[0143] Unlike conventional simple and fast discharge, this method can dynamically adjust the discharge parameters according to the real-time status of the battery to achieve efficient and flexible adaptive discharge. For L1-level batteries, since their performance is close to that of new batteries, they can be automatically discharged in constant current mode. By real-time monitoring of the first voltage change, once the first voltage approaches the safety lower limit (such as 2.7V), the current is cut off in time to ensure that the remaining capacity is fully utilized and irreversible capacity loss is not caused by over-discharge. For L2-level batteries, segmented constant current adaptive discharge can be implemented. By setting the first critical voltage, judging the downward trend of the second voltage, and automatically switching to a low rate current, more capacity can be released and electrode damage caused by voltage drops can be prevented. For L3-level batteries, a constant voltage and constant current collaborative control strategy is adopted. The constant current is first constant to the second critical voltage and then automatically transferred to the constant voltage stage. The attenuation of the third current is monitored in real time until the current is close to 0 before the discharge is terminated. This not only avoids the hazards of undervoltage and overvoltage, but also makes deep use of the remaining energy. For highly aged L4 batteries, pulsed intermittent discharge can be used, with periodic short-term discharge and shelving. The pulse width and intermittent time can be automatically adjusted according to the changes in the fourth voltage until the battery fourth voltage is stabilized within a safe range.

[0144] During the entire discharge process, the various state parameters of the battery are recorded in detail, such as initial voltage, termination voltage, average voltage, discharge capacity, average current, discharge time, and number of pulses; discharge curves of batteries with different aging levels, including data on changes in voltage and current over time; performance parameters such as discharge capacity, energy, and efficiency of batteries with different aging levels; key characteristic point data in the differentiated discharge process, such as segmented point voltage, current, and termination point voltage, etc.; forming rich and detailed first discharge data. The first discharge data covers the complete discharge behavior characteristics of batteries with four aging levels under differentiated adaptive discharge, and is an important basis for comprehensively evaluating the residual value of waste batteries. In short, this adaptive discharge method can not only release battery power quickly and efficiently, maximize resource recycling, but also fully consider the aging characteristics of the battery, avoid secondary damage during the discharge process, and maintain the residual value of the battery. Through precise discharge and data accumulation, it can not only provide support for cascade utilization and green remanufacturing, but also accumulate valuable experience for battery life cycle management and health diagnosis.

[0145] Step S2000, dismantling the discharged waste lithium-ion battery to obtain positive electrode materials and negative electrode materials, extracting second characteristic information of the positive electrode materials and the negative electrode materials, classifying the positive electrode materials and the negative electrode materials into different performance levels according to the second characteristic information, and determining a recycling scheme corresponding to each performance level; recycling and regenerating the positive electrode materials and the negative electrode materials of each performance level according to the recycling scheme to obtain a regenerated positive electrode material and a regenerated negative electrode material;

[0146] Furthermore, step S2000 includes:

[0147] Step S2100, disassembling the discharged waste lithium-ion battery to obtain positive electrode materials and negative electrode materials;

[0148] Step S2200, extracting second characteristic information of the positive electrode material and the negative electrode material, wherein the second characteristic information includes material morphology information, material composition information and material structure information;

[0149] Specifically, the disassembly process must be carried out in an oxygen-free and dust-free environment to avoid oxidation or secondary contamination of materials. The use of automated and sophisticated disassembly equipment can significantly improve disassembly efficiency and material integrity. Hot melt cutting technologies such as laser cutting and plasma cutting can accurately separate the internal structure of the battery to prevent tearing and breaking. Vacuum suction can remove residual liquid to the maximum extent, which is conducive to subsequent material purification. Physical cleaning can preliminarily remove impurities on the surface of the material in preparation for chemical purification. Reasonable sorting, collection, and storage can ensure that different materials are handled separately to avoid cross contamination. Scientific and standardized battery disassembly is a key link in realizing the utilization of the entire value chain of waste batteries.

[0150] Step S2200 is based on material extraction and uses advanced material characterization and analysis techniques to deeply explore the morphology, composition and structural evolution of battery materials during long-term use, accurately evaluate the degree and mechanism of material aging and degradation, and provide a scientific basis for material graded recycling and customized regeneration. Scanning electron microscopy (SEM) is used to characterize the surface morphology of positive and negative electrode materials, and microscopic morphological images of the materials are obtained as material morphological information; by comparing the morphological changes before and after decay, the external manifestations and microscopic mechanisms of material aging failure are judged; X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES) and other testing methods are used to analyze the phase composition, element content, etc. of positive and negative electrode materials to obtain qualitative and quantitative material composition information; by comparing the changes in composition before and after decay, the chemical changes and reaction mechanisms during the material aging process are judged; transmission electron microscopy (TEM), Raman spectroscopy (Raman), X-ray absorption fine structure (XAFS) and other characterization methods are used to analyze the crystal structure, bonding mode, coordination environment, etc. of positive and negative electrode materials to obtain key information reflecting the microstructure of the material; by comparing the evolution of the microstructure before and after decay, the structural origin and internal mechanism of material aging failure are revealed.

[0151] Material morphology information is mainly obtained through SEM, which can intuitively present the microscopic morphology of the material surface, such as the size, shape, distribution of particles, and morphological changes such as volume expansion, cracking, and pulverization caused by charge and discharge cycles, revealing the external manifestations of material performance degradation. Material composition information is mainly obtained through XRD, XPS, and ICP-OES, which can qualitatively and quantitatively analyze the material's phase composition, chemical valence, element content, and chemical reactions such as phase change, dissolution, and deposition caused by the charge and discharge process, and clarify the chemical origin of material aging. Material structure information is mainly obtained through TEM, Raman, and XAFS, which can go deep into the lattice scale to characterize the material's crystal structure, bond length, bond angle, coordination number and other microstructural parameters, as well as charge and discharge-induced structural distortion, disorder, and reconstruction, revealing the structural roots of material performance degradation. Through systematic collection and in-depth analysis of the second characteristic information, the intrinsic relationship between material performance degradation and morphology, composition, and structural evolution is established, and a comprehensive material aging degradation mechanism is constructed, which can provide theoretical guidance and experimental basis for subsequent material classification and regeneration scheme design. Only on the basis of a deep understanding of material properties can we formulate targeted material recycling and regeneration strategies, maximize the restoration of its physical and chemical properties, and achieve high-value cascade utilization.

[0152] Step S2300, according to the second characteristic information, the positive electrode material and the negative electrode material are respectively divided into different performance levels, and a recycling scheme corresponding to each performance level is determined; the positive electrode material and the negative electrode material of each performance level are recycled and regenerated according to the recycling scheme to obtain a regenerated positive electrode material and a regenerated negative electrode material;

[0153] Furthermore, if Figure 5 As shown, step S2300 includes:

[0154] Step S2310, calculating the morphology integrity index IM based on the material morphology information;

[0155] Step S2320, calculating a component retention index IC based on the material component information;

[0156] Step S2330, calculating the structural integrity index IS based on the material structure information;

[0157] Step S2340, performing weighted average on the morphology integrity index IM, the component retention index IC and the structure integrity index IS to obtain the material performance index IP;

[0158] Step S2350: classify the positive electrode material and the negative electrode material into different performance levels according to the material performance index IP.

[0159] The classification of positive electrode materials and negative electrode materials into different performance levels according to the material performance index IP includes:

[0160] When IP1 < IP ≤ 100%, the material properties are optimal and classified as P1 level, where IP1 is the first performance threshold.

[0161] When IP2 < IP ≤ IP1, the material properties are second-best and classified as P2 level, where IP2 is the second performance threshold and IP1 > IP2.

[0162] When 0 < IP ≤ IP2, the material properties are relatively poor and classified as P3 level.

[0163] Specifically:

[0164] Calculation of the morphology integrity index IM: Observe the surface morphology of the material using a scanning electron microscope (SEM) to obtain a series of SEM images. Process the SEM images using image analysis software to extract defect information such as holes and cracks on the material surface. Based on parameters such as area ratio and length, quantitatively evaluate the degree of surface defects of the material, and establish the morphology integrity index IM as the morphological basis for performance grade classification. The higher the IM value, the more complete the surface morphology of the material, the more stable the microstructure, and the greater the potential for recycling and reuse. For example, for a certain batch of waste battery cathode materials, SEM analysis shows that the surface crack area ratio is 5% and the hole area ratio is 3%. Based on this, IM = 92% is calculated, indicating that the surface morphology of this material is relatively complete and has a high recycling value.

[0165] Calculation of the composition retention index IC: Analyze the element content of the material using techniques such as X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma optical emission spectroscopy (ICP-OES). Compare the key element content of the material with the original value and quantitatively calculate the retention rate of each element. Based on the weighted average of the element retention rate and element importance, obtain the composition retention index IC as the chemical basis for performance grade classification; the higher the IC value, the more stable the chemical composition of the material, the more active substances are retained, and the greater the recycling value of the material. For example, for a certain batch of ternary cathode materials, XRF measures that the retention rates of nickel, cobalt, and manganese elements are 95%, 92%, and 97% respectively. Assuming the importance weights of the three elements are 0.4, 0.3, and 0.3 respectively, then IC = 0.4×95% + 0.3×92% + 0.3×97% = 94.9%, indicating that the chemical composition retention degree of the material is very high, the loss of active substances is very small, and the recycling value of the material is large.

[0166] Calculation of the structural integrity index IS: X-ray diffraction (XRD), transmission electron microscopy (TEM) and other means are used to characterize the crystal structure of the material. The degree of lattice distortion is calculated based on the diffraction peak displacement and peak width change; the average grain size and distribution are calculated by TEM image analysis; the defect density of the material is quantitatively calculated in combination with the XRD data. Based on the above structural parameters, the structural integrity index IS is constructed to quantitatively evaluate the degree of structural degradation of the material as a physical basis for the performance grade classification; the higher the IS value, the more stable the crystal structure of the material, the better the microstructure integrity, and the greater the material regeneration potential. For example, for a waste battery graphite negative electrode, XRD analysis shows that its interlayer spacing increases from the original 0.3354nm to 0.3358nm, and the lattice expansion rate is 0.12%; TEM observation shows that its average grain size decreases from the original 10μm to 8μm; the defect density decreases from the original 10 3 cm -2 Increase to 10 5 cm -2 Based on this calculation, IS=85%, indicating that the material structure has been significantly degraded but can still be repaired, and regeneration measures such as surface modification are advisable.

[0167] At the macro level, the macro integrity of the material is mainly reflected through the material morphology information. The morphology integrity index IM can be obtained by weighted average of parameters such as fracture ratio and degree of pulverization. It intuitively reflects the degree of physical damage suffered by the material during mechanical disassembly. The larger the IM value, the more complete the material morphology and the better the physical properties. At the micro level, the focus is on the chemical properties of the material. The component retention index IC is calculated by comprehensively calculating the element content, stoichiometric ratio, impurity content and other parameters of the surface and bulk of the material. The closer the IC value is to 100%, the more stable the chemical composition of the material, the closer it is to the original state, and the higher the value. The structural integrity index IS takes into account both the macro morphology and the micro structure, and is evaluated through characterization data such as XRD spectrum, lattice parameters, specific surface area, porosity, and agglomeration state. The larger the IS, the higher the integrity of the material in terms of crystal structure, pore structure, specific surface area, etc., the more active sites are retained, and the better the electrochemical performance.

[0168] Finally, the three sub-indicators of IM, IC, and IS are added and averaged according to certain weights to obtain a comprehensive material performance index IP. IP is a multidimensional evaluation index that takes into account morphology, composition, and structure, and can more comprehensively reflect the performance status of the material. The higher the IP, the better the comprehensive performance of the material and the greater its recycling value. Based on this, the materials are divided into three levels: when the IP is between IP1 (such as 90%) and 100%, the material has excellent performance indicators and has extremely high recycling value, and is classified as P1, which should be recycled first; when the IP is between IP2 (such as 70%) and IP1, the material performance is slightly degraded but can still be used, and is classified as P2, which should be selectively recycled; and when the IP is lower than IP2, the material has been severely deteriorated and has a low recycling value, and is classified as P3, and it is recommended to be discarded or recycled.

[0169] For P1-grade materials, since their morphology, composition, and structure are all kept at their best, and the performance index IP is close to 100%, they have the highest recycling value. Priority should be given to their direct recycling and reuse, and they should be re-prepared into electrode materials after appropriate treatment for the production of new batteries. First, the P1-grade positive and negative materials are recycled separately, and after preliminary screening and cleaning to remove surface impurities, they are deeply sorted according to the type of materials. For example, for ternary positive electrode materials, physical methods such as gravity and magnetic separation can be used for purification and separation; for graphite negative electrode materials, screening, airflow classification and other means can be used for enrichment. The high-purity P1-grade positive and negative electrode materials obtained by sorting are then fine-tuned through surface modification, coating and other links to improve the conductivity, cycle stability and other properties of the materials. For example, the surface of the ternary positive electrode is coated to construct a core-shell structure, which can effectively inhibit the interface side reactions and improve the rate performance. Moderate doping of the graphite negative electrode can improve the first coulomb efficiency and improve the rate performance. The P1-level regenerated positive and negative materials obtained in this way have regular morphology, controllable composition, stable structure, and comprehensive performance comparable to or even exceeding that of the original materials. They can be directly used in battery electrode manufacturing to achieve cascade utilization. This method is simple in process, low in cost, high in added value, and can retain material performance to the greatest extent. It is the preferred solution for P1-level material recycling.

[0170] For P2-level materials, the morphology, composition, and structure have degraded to a certain extent, and the performance index IP has decreased but is still above the threshold. It has the potential for recycling and reuse, but it needs to be treated differently according to the material type and aging characteristics. Further identification can be made based on the material type, aging characteristics, etc., and high-value P2-level materials can be selected for priority recycling. For those that cannot be directly used, refining and regeneration can be considered. For example, for ternary positive electrode materials, if the morphology is not obviously damaged, the main components are intact, the structure is basically stable, and only the surface has slight coating damage and residual alkali accumulation, then de-coating, chemical cleaning and other methods can be used to remove surface impurities and restore the bulk activity. After treatment, it is modified by appropriate coating and mixed with P1-level positive electrode materials to prepare secondary battery positive electrodes with excellent performance. For graphite negative electrodes, if its layered structure is basically intact, only the surface SEI film is thickened and the electrolyte remains, high-temperature carbonization, chemical etching and other means can be used to remove the accumulated passivation film and impurities on the surface, expose the fresh graphite layer, and restore the fast charging and discharging ability. After treatment, it can be mixed with P1-level negative electrode to obtain stable negative electrode materials. However, for P2-level materials with serious morphological collapse, component dissolution, and structural collapse, the cost-effectiveness of direct physical recycling and reuse is relatively low. At this time, hydrometallurgical processes can be given priority. Through chemical methods of dissolution and precipitation, the material components can be recovered and resynthesized. The obtained ternary precursor or negative electrode graphitized intermediate is then sintered and doped to prepare a stable regenerated material. In this way, on the basis of recycling most of the material components, harmful impurities can be removed, the material components can be adjusted, and the crystal structure can be repaired, so that the low-cost P2-level materials can be "reborn".

[0171] For P3 grade materials, the morphology, composition and structure of the materials have been seriously degraded, the integrity has been destroyed, the materials have been "completely changed", the IP index is low, and there is not much practical significance for continuing to use them electrochemically. However, as the "ore" of metals and carbon, they still have recycling value, so metallurgical means such as smelting and roasting should be adopted to melt and reduce under high temperature conditions, directly precipitate metal elements and carbon raw materials, and make them into battery-grade metal salts, carbon materials, etc. after deep processing to achieve value re-creation. For example, for the ternary positive electrode, it is first crushed and leached, and the nickel, cobalt and manganese therein are fully dissolved with an acid solution to obtain a metal ion solution. After extraction, crystallization and sintering, high-purity nickel sulfate, cobalt sulfate, manganese sulfate and other metal salts can be obtained, which are then used for downstream material synthesis. The residue is further roasted and activated to obtain high specific surface area carbon powder, which is used as a conductive filler, etc. For the graphite negative electrode, it will undergo carbon precipitation and graphitization under high temperature pyrolysis conditions, and can be directly reduced to highly oriented graphite, accompanied by impurity gasification and volatilization, ash analysis, and automatic purification. The obtained high-purity graphite can be used in the fields of negative electrode conductive agent, thermal conductive filler, etc. after being crushed and screened. Although the P3-level material can not be directly recycled to obtain battery-grade materials, it can achieve the efficient separation and recycling of valuable elements, turning "waste" into treasure. Compared with the end-of-life disposal of landfill and incineration, it can greatly reduce the environmental load and resource consumption, and has good economic and social benefits.

[0172] In summary, differentiated recycling strategies should be adopted for waste battery materials of different performance levels. For P1-level materials, priority should be given to direct physical reuse, and their original performance advantages should be retained as much as possible; for P2-level materials, policies should be implemented according to the materials, and high-value materials should be selected for priority recycling, and those that are difficult to directly use should be recycled and resynthesized by chemical methods; for P3-level materials, the focus should be on the separation of valuable elements and the utilization of raw materials, and a cascade cycle should be achieved through metallurgical smelting and reduction. Such a hierarchical recycling system can fully match the characteristics of materials, give full play to the expertise of each link, and maximize benefits while efficiently transforming resources, contributing to the virtuous cycle of the battery industry and environmental protection. This is of great significance for promoting resource conservation and recycling, and supporting the sustainable development of the new energy industry.

[0173] The calculation of the morphology integrity index IM includes:

[0174]

[0175] in:

[0176] IM: morphology integrity index, ranging from 0% to 100%, the higher the value, the more complete the material surface morphology.

[0177] w C : Surface crack area, expressed in mm 2, use image analysis software to extract from SEM images and calculate the area of ​​cracks on the total surface; reflect the degree of defects on the material surface, the larger the crack area, the lower the integrity of the material;

[0178] w P : Surface hole area, expressed in mm 2 , image analysis software is also used to analyze the holes and calculate the total area of ​​the holes; the presence of holes will also affect the integrity of the material. The larger the area, the more incomplete the material.

[0179] A T : Total surface area of ​​the material, expressed in mm 2 , measured from SEM images or calculated based on material size, provides a benchmark for defect proportion, reflecting the relative importance of defects in the total surface;

[0180] L R : The retention ratio of the surface feature length, expressed in mm, is used to calculate the length of the features on the material surface (such as edges, surface roughness, etc.), reflecting the integrity of the surface features of the material at the microscopic level;

[0181] L T : The total characteristic length of the material, expressed in mm, is calculated based on the geometric characteristics of the material surface and is used to compare the ratio of the retained features to the overall features;

[0182] α': morphology integrity weighting factor, which is determined by regression analysis based on experimental data and adjusts the weight of the impact of cracks and holes on the overall morphology integrity;

[0183] β': Topographic feature weighting factor, determined by regression analysis based on experimental data, to adjust the effect of surface feature length on integrity.

[0184] When C or P When L increases, the IM value will decrease, indicating that the integrity of the material is reduced and the recycling value is reduced; R When α' and β' increase, the IM value will increase, indicating that the material microstructure is more stable and the recycling potential is enhanced; by adjusting α' and β', the integrity of different materials can be adaptively evaluated, thereby improving the applicability of the formula.

[0185] This formula combines the surface defect area and surface characteristic length to provide a comprehensive evaluation index that helps to determine the recycling potential of materials. By quantifying various parameters, it can more accurately reflect the actual morphological state of the material. According to different IM values, different recycling plans can be formulated to optimize resource utilization.

[0186] Step S3000, using the regenerated positive electrode material and the regenerated negative electrode material to prepare a new lithium-ion battery, performing a charge and discharge test on the new lithium-ion battery to obtain second discharge data; comparing the first discharge data with the second discharge data, evaluating the performance of the new lithium-ion battery, and then judging the feasibility of recycling the waste battery.

[0187] Furthermore, step S3000 includes:

[0188] Step S3100, using the regenerated positive electrode material and the regenerated negative electrode material to prepare a new lithium-ion battery; specifically, using the regenerated positive electrode material and the regenerated negative electrode material obtained in step S2000, refer to the design parameters of existing commercial lithium-ion batteries, such as battery cell thickness, surface capacity, N / P ratio, etc., to prepare a new battery. According to the preset mass percentage of positive electrode active material, conductive agent, and binder, such as 8:1:1, the three substances are mixed evenly to obtain a positive electrode slurry. Then, the slurry is evenly coated on the aluminum foil current collector with a coating tool such as a scraper, and the thickness is controlled to be 100-200μm. After coating, it is placed in an oven at 80℃ and dried for 2h to remove the solvent. After drying, it is rolled with a roller press to reduce the thickness to 50-80μm to obtain a new positive electrode. The preparation of the negative electrode is similar to that of the positive electrode, except that the current collector is replaced with copper foil, and the compacted thickness is smaller, about 30-50μm. When assembling the battery, the prepared new positive electrode and new negative electrode are separated by a diaphragm to prevent the two electrodes from directly contacting and short-circuiting. The diaphragm is usually made of porous polypropylene, polyethylene, etc. A layer of ceramic coating is first applied to the diaphragm, and then rolled with a roller press. The electrodes and diaphragms are stacked in sequence and inserted into the battery casing. After vacuuming, the electrolyte is injected. The electrolyte consists of a high-purity carbonate solvent and a lithium salt. Finally, the mouth is heat-sealed and the tabs are led out to obtain a new lithium-ion battery product. The entire preparation process must be carried out in a dry inert atmosphere such as argon to prevent the battery materials from being contaminated by oxygen and water vapor.

[0189] Using recycled materials extracted from waste batteries to prepare new batteries not only saves resources and shortens the battery manufacturing cycle, but also the preparation process is basically the same as that of conventional lithium-ion batteries. There is no need to redesign the production line, which is easy to promote industrialization. The processing performance, particle size and morphology of recycled materials should be as close as possible to the original materials. The purity and electrochemical properties of recycled materials are key factors affecting the performance of new batteries. The process parameters of coating, rolling and other processes should be optimized to match the characteristics of recycled materials. In short, new lithium-ion batteries should maximize the use of recycled materials and realize the closed-loop circulation of waste batteries while ensuring performance and life.

[0190] Step S3200, performing a standardized charge and discharge test on the new lithium-ion battery to obtain second discharge data; the second discharge data includes a second discharge specific capacity C2, a second cycle life N2, and a second self-discharge rate S2;

[0191] Specifically, step S3200 can comprehensively examine the core indicators of the new battery such as specific capacity, cycle life, self-discharge, etc. through standardized charge and discharge tests, and objectively evaluate its energy storage performance and use value. The so-called standardized charge and discharge test refers to the repeated charge and discharge of the battery at a specified charge and discharge rate (such as 0.5C charge and discharge) under specific environmental conditions (such as temperature 25±2℃, relative humidity 45%~85%) in strict accordance with internationally accepted test specifications and operating procedures until its capacity decays to less than 80% of the rated capacity. Through multiple consecutive charge and discharge cycles and performance characterization, a series of objective and real test data are obtained.

[0192] The second discharge specific capacity refers to the amount of electricity released per unit mass or volume of a new battery during a standard charge and discharge test. It reflects the energy density level of the battery and is the primary indicator for measuring energy storage performance. The higher the specific capacity, the more power the battery can provide at the same mass or volume, which is expected to extend battery life, reduce battery size, and reduce equipment weight. If the specific capacity of the new battery is significantly higher than that of a conventional battery, it means that the cascaded recycled material system has significant advantages and has achieved beneficial improvements in conductivity, structure, etc., so that more lithium ions can be stored and released under the same conditions, thereby increasing the lithium insertion capacity and lithium de-lithium capacity.

[0193] The second cycle life refers to the number of charge and discharge times that a new battery experiences when its capacity or performance decays to a certain level (such as 80% of the initial capacity) during repeated charge and discharge cycles. It reflects the service life and cycle stability of the battery and is an important basis for judging the durability of the battery. The longer the cycle life, the more times the battery can withstand charge and discharge without significant capacity loss, and the longer the service life. This is especially important for power batteries and energy storage batteries, which determine the mileage and replacement cycle of electric vehicles, as well as the economy and reliability of peak and frequency regulation of power grids. If the cycle life of a new battery significantly exceeds that of a conventional battery, it means that the materials obtained by cascade utilization not only have advantages in initial capacity, but also have made great progress in cycle stability. This may be due to the improvement of the purity of recycled materials, the repair of crystal structure, material compounding and coating, thereby inhibiting the capacity decay mechanisms such as lattice collapse, structural collapse, and interface erosion during the cycle, greatly extending the battery life.

[0194] The second self-discharge rate refers to the rate of capacity loss of a new battery during static storage due to factors such as impurity contamination and spontaneous lithium insertion. It reflects the storage performance and charge retention capacity of the battery, which is particularly critical for backup batteries and mobile devices. The lower the self-discharge rate, the longer the battery can maintain a higher state of charge without obvious "power loss", thereby extending the storage period and reducing the maintenance frequency. If the self-discharge rate of a new battery is much lower than that of a conventional battery, it means that the use of recycled materials not only improves the reversibility of charge and discharge, but also suppresses spontaneous side reactions and improves inventory stability. This may be attributed to the reduction of impurity content, the optimization of surface coating, the rational use of additives, etc., thereby reducing factors that induce increased self-discharge such as electrolyte decomposition and transition metal dissolution, allowing the battery to be charged for a long time.

[0195] On the whole, if the specific capacity, cycle life, self-discharge and other indicators of the new battery are significantly better than those of conventional batteries, it can be determined that the materials obtained by cascade utilization have a significant improvement effect on battery performance. On the one hand, the optimization of the activity, conductivity, structure and other aspects of the recycled materials has improved the specific capacity level, reduced the polarization impedance, and laid a material foundation for higher energy density and rate performance. On the other hand, the recycling process effectively removes impurity pollution, repairs lattice defects, and inhibits capacity attenuation inducements such as electrolyte decomposition and metal dissolution, thereby greatly extending the cycle life, reducing the self-discharge rate, and promoting the long life and high stability of the battery. The fundamental reason for these positive changes is that after a series of treatments such as fine disassembly, sorting, repair, and compounding, the structural integrity and electrochemical activity of the materials are restored to a certain extent, the "root cause" of performance attenuation is removed, and the material potential is activated, so that it can be used again in battery manufacturing and reflects excellent comprehensive performance in actual charging and discharging applications. This not only proves the technical feasibility of cascade utilization, realizes the high-value recycling of waste battery materials, and improves resource and energy efficiency; it also shows that the new battery has not only improved in single indicators such as specific capacity, but also achieved overall optimization in multiple performance aspects such as cycle, rate, storage, etc., which will fundamentally enhance the use value of the battery, extend its service life, and promote the green and sustainable development of the battery industry.

[0196] Step S3300, comparing the first discharge data with the second discharge data to judge the feasibility of recycling the waste battery.

[0197] Furthermore, if Figure 6 As shown, step S3300 includes:

[0198] Step S3310, comparing the first discharge specific capacity C1 with the second discharge specific capacity C2, and calculating the capacity recovery rate η of the new lithium-ion battery C ;

[0199] Step S3320, comparing the first cycle life N1 with the second cycle life N2, and calculating the cycle life improvement rate η of the new lithium-ion battery N ;

[0200] Step S3330, comparing the first self-discharge rate S1 with the second self-discharge rate S2, and calculating the self-discharge control coefficient η of the new lithium-ion battery S ;

[0201] Step S3340, comprehensively considering the capacity recovery rate η of the new lithium-ion battery C , cycle life improvement rate η N and self-discharge control coefficient η S , calculate the performance evaluation index P of the new lithium-ion battery R ;

[0202] Step S3350, setting the performance index threshold θ P , if P R ≥θ P , it is judged that the new lithium-ion battery has good performance and the recycling of waste batteries is feasible.

[0203] Specifically, step S3300 is to comprehensively evaluate the effect of recycling the waste batteries through comparative analysis after obtaining the key performance parameters of the waste batteries and the new lithium-ion batteries. C =(C2) / (C1)×100%, η C The closer or more than 100%, it indicates that the capacity of the new lithium-ion battery has been restored to a level close to or exceeding that of the old battery, and its energy storage performance has been effectively restored. N =(N2) / (N1)×100%; η N The larger the value, the greater the cycle stability of the new lithium-ion battery is, and the longer the service life is. S =(S1) / (S2); η S The larger the capacity, the lower the self-discharge rate of the new lithium-ion battery is, and its storage performance is greatly improved. C , cycle life improvement rate η N , self-discharge control coefficient η S The improvement of the performance of new lithium-ion batteries compared with old batteries is quantitatively described from the three perspectives of capacity, life, and self-discharge. C , η N , η S The weighted sum of the three sub-indicators gives a quantitative score of the regeneration effect, namely the performance evaluation index P. R When the performance evaluation index of the new lithium-ion battery P RThe larger the value, the more obvious the comprehensive performance of new lithium-ion batteries is compared with old batteries, and the better the recycling effect is. R When the battery exceeds a certain critical value (e.g. 85%), it can be considered that the waste battery is worth regenerating for secondary utilization; R When it is too low, the input-output ratio of recycling may be difficult to achieve a balance, so it is better to directly recycle the materials and recycle them.

[0204] For example, suppose a batch of used batteries made of ternary materials has an initial capacity of 2500mAh. After 300 cycles, the capacity drops to 1875mAh, and the self-discharge rate is as high as 15% / month, which is no longer suitable. After regeneration, the capacity rises to 2400mAh, and it can be stably cycled for more than 500 times under standard conditions, and the self-discharge rate drops to 5% / month. Based on this, it can be calculated:

[0205] η C =(2400mAh) / (1875mAh)×100%=128%;

[0206] η N =(500) / (300)×100%=167%;

[0207] η S =(15% / month) / (5% / month)=3;

[0208] It can be seen that after the recycling of this batch of waste batteries, the capacity has been restored to a level higher than that of the waste state, the cycle life has been extended by nearly 70%, and the self-discharge rate has been reduced to 1 / 3 of the original. R =0.5η C +0.3η N +0.2η S , we can get:

[0209] P R =0.5×128%+0.3×167%+0.2×3=174.1%;

[0210] The comprehensive performance index of the new lithium-ion battery is as high as 174.1%, indicating that its performance has been greatly improved in all aspects and has full cascade utilization value, and can be used for secondary applications such as energy storage and backup power supply.

[0211] This case fully demonstrates that by scientifically evaluating the performance improvement effect of new lithium-ion batteries and constructing quantitative indicators, it can provide important basis and reference for the selection of waste battery resource recovery paths and full life cycle management decisions. This is of great significance for extending the battery value chain, improving resource utilization efficiency, and promoting the sustainable development of the battery industry.

[0212] Example 2

[0213] This embodiment provides a waste lithium-ion battery cascade recovery and reuse system based on the embodiment 1, such as Figure 7 As shown, including:

[0214] Aging grade classification module: used to collect the first characteristic information of the waste lithium-ion batteries, and classify the waste lithium-ion batteries into different aging grades according to the first characteristic information;

[0215] Discharge module: used to design differentiated target discharge curves for batteries of each aging level, and to perform precise adaptive discharge on waste lithium-ion batteries of each aging level according to the differentiated target discharge curves to obtain first discharge data;

[0216] Recycling module: used to disassemble the discharged waste lithium-ion batteries to obtain positive electrode materials and negative electrode materials, extract the second characteristic information of the positive electrode materials and the negative electrode materials, classify the positive electrode materials and the negative electrode materials into different performance levels according to the second characteristic information, and determine the recycling scheme corresponding to each performance level; according to the recycling scheme, recycle and regenerate the positive electrode materials and negative electrode materials of each performance level to obtain regenerated positive electrode materials and regenerated negative electrode materials;

[0217] Regeneration module: used to prepare new lithium-ion batteries using recycled positive electrode materials and recycled negative electrode materials;

[0218] Comparison module: used to perform charge and discharge tests on new lithium-ion batteries to obtain second discharge data; compare the first discharge data with the second discharge data to judge the feasibility of recycling used batteries.

[0219] In the aging level classification module, the first characteristic information includes a battery type parameter, a battery capacity parameter, a battery voltage parameter, and a battery usage time parameter; and the classification of waste lithium-ion batteries into different aging levels according to the first characteristic information includes:

[0220] Step S1210, based on the battery capacity parameter, calculating the capacity retention rate of the waste lithium-ion battery as the first decision variable for aging grade classification;

[0221] Step S1220, based on the battery voltage parameter, calculating the voltage decay rate of the waste lithium-ion battery as a second decision variable for aging grade classification;

[0222] Step S1230, based on the battery usage time parameter, calculating the usage time coefficient of the waste lithium-ion battery as the third decision variable for aging level classification;

[0223] Step S1240, the battery aging coefficient is calculated by combining the capacity retention rate, the voltage decay rate and the usage time coefficient. L, the aging levels of used lithium-ion batteries are divided into L1, L2, L3, and L4.

[0224] When θ3≤θ L ≤1, classified as L1, indicating that the battery is basically not aged and has good performance, θ3 is the third aging threshold;

[0225] When θ2≤θ L When <θ3, it is classified as L2, indicating that the battery is slightly aged but the performance is acceptable. θ2 is the second aging threshold.

[0226] When θ1≤θ L <θ2, it is classified as L3, indicating that the battery is moderately aged and the performance is significantly degraded. θ1 is the first aging threshold, and θ3>θ2>θ1;

[0227] When 0<θ L When <θ1, it is classified as L4, indicating that the battery is severely aged and the performance is seriously degraded.

[0228] In the discharge module, the differentiated target discharge curves include an L1 target discharge curve, an L2 target discharge curve, an L3 target discharge curve, and an L4 target discharge curve; and for each aging level of the battery, designing a differentiated target discharge curve includes:

[0229] Step S1310, for the L1 level battery, a constant current discharge mode is used for discharge, the real-time voltage of the L1 level battery is marked as a first voltage, AM1 times the rated capacity is used as the discharge current, and the discharge is stopped when the first voltage drops to a preset first termination voltage, so as to obtain an L1 level target discharge curve;

[0230] Step S1320, for the L2 level battery, a segmented constant current discharge mode is adopted, the real-time voltage of the L2 level battery is marked as the second voltage, AM2 times the rated capacity is first used as the discharge current, when the second voltage drops to the first critical voltage, the current is automatically switched, and AM3 times the rated capacity is used as the discharge current, and the discharge is stopped when the second voltage drops to the preset second termination voltage, and the L2 level target discharge curve is obtained; wherein, AM1>AM2>AM3;

[0231] Step S1330, for the L3 level battery, a constant voltage and constant current two-stage discharge mode is adopted, the real-time voltage of the L3 level battery is marked as the third voltage, the real-time current of the L3 level battery is marked as the third current, and the constant current is first discharged. When the third voltage drops to the second critical voltage, it is automatically converted to constant voltage discharge. When the third current drops to 0.05C, the discharge is stopped, and the L3 level target discharge curve is obtained;

[0232] Step S1340, for the L4 level battery, pulse discharge is used for discharge, the real-time voltage of the L4 level battery is marked as the fourth voltage, and the discharge is stopped when the fourth voltage drops to the preset fourth termination voltage, so as to obtain the L4 level target discharge curve.

[0233] In the discharge module, the first discharge data includes a first discharge specific capacity C1, a first cycle life N1, and a first self-discharge rate S1; and the method of performing precise adaptive discharge on waste lithium-ion batteries of various aging levels according to differentiated target discharge curves includes:

[0234] Step S1410, performing precise adaptive discharge on the L1 level waste lithium ion battery according to the L1 level target discharge curve to obtain L1 level discharge data, and obtaining a first discharge specific capacity, a first cycle life, and a first self-discharge rate of the L1 level battery according to the L1 level discharge data;

[0235] Step S1420, performing precise adaptive discharge on the L2 level waste lithium ion battery according to the L2 level target discharge curve to obtain L2 level discharge data, and obtaining a first discharge specific capacity, a first cycle life, and a first self-discharge rate of the L2 level battery according to the L2 level discharge data;

[0236] Step S1430, performing precise adaptive discharge on the L3 level waste lithium-ion battery according to the L3 level target discharge curve to obtain L3 level discharge data, and obtaining a first discharge specific capacity, a first cycle life, and a first self-discharge rate of the L3 level battery according to the L3 level discharge data;

[0237] Step S1440, performing precise adaptive discharge on the L4 level waste lithium-ion battery according to the L4 level target discharge curve to obtain L4 level discharge data, and obtaining a first discharge specific capacity, a first cycle life, and a first self-discharge rate of the L4 level battery according to the L4 level discharge data;

[0238] Step S1450, weighted average the first discharge specific capacities of L1, L2, L3, and L4 level batteries to obtain the first discharge specific capacity in the overall first discharge data; weighted average the first cycle life of L1, L2, L3, and L4 level batteries to obtain the first cycle life in the overall first discharge data; weighted average the first self-discharge rates of L1, L2, L3, and L4 level batteries to obtain the first self-discharge rate in the overall first discharge data.

[0239] In the recycling module, the second characteristic information includes material morphology information, material composition information and material structure information; and the positive electrode material and the negative electrode material are classified into different performance levels according to the second characteristic information, including:

[0240] Step S2310, calculating the morphology integrity index IM based on the material morphology information;

[0241] Step S2320: Calculate the component retention index IC based on the material composition information;

[0242] Step S2330: Calculate the structural integrity index IS based on the material structure information;

[0243] Step S2340: Perform a weighted average on the morphology integrity index IM, the component retention index IC, and the structural integrity index IS to obtain the material performance index IP;

[0244] Step S2350: Classify the cathode material and the anode material into different performance grades according to the material performance index IP.

[0245] The classifying the cathode material and the anode material into different performance grades according to the material performance index IP includes:

[0246] When IP1 < IP ≤ 100%, the material performance is optimal and it is classified as grade P1, where IP1 is the first performance threshold;

[0247] When IP2 < IP ≤ IP1, the material performance is second-best and it is classified as grade P2, where IP2 is the second performance threshold and IP1 > IP2;

[0248] When 0 < IP ≤ IP2, the material performance is poor and it is classified as grade P3.

[0249] In the comparison module, the second discharge data includes the second discharge specific capacity C2, the second cycle life N2, and the second self-discharge rate S2; the comparing the first discharge data with the second discharge data to evaluate the feasibility of recycling used batteries includes:

[0250] Step S3310: Compare the first discharge specific capacity C1 with the second discharge specific capacity C2, and calculate the capacity recovery rate η of the new lithium-ion battery C ;

[0251] Step S3320: Compare the first cycle life N1 with the second cycle life N2, and calculate the cycle life improvement rate η of the new lithium-ion battery N ;

[0252] Step S3330: Compare the first self-discharge rate S1 with the second self-discharge rate S2, and calculate the self-discharge control coefficient η of the new lithium-ion battery S ;

[0253] Step S3340: Considering comprehensively the capacity recovery rate η of the new lithium-ion battery C , the cycle life improvement rate η N and the self-discharge control coefficient η S , calculate the performance evaluation index P of the new lithium-ion battery R ;

[0254] Step S3350, setting the performance index threshold θ P , if P R ≥θ P , it is judged that the new lithium-ion battery has good performance and the recycling of waste batteries is feasible.

[0255] Example 3

[0256] This embodiment discloses an electronic device, which may include one or more processors and one or more memories, wherein the memories store computer-readable codes, and when the computer-readable codes are executed by the one or more processors, the above-mentioned method for cascade recycling and reuse of waste lithium-ion batteries can be executed.

[0257] The method or system according to the embodiment of the present application can also be implemented with the help of the architecture of an electronic device. The electronic device may include a bus, one or more CPUs, a read-only memory (ROM), a random access memory (RAM), a communication port connected to a network, an input / output component, a hard disk, etc. A storage device in the electronic device, such as a ROM or a hard disk, can store the method for cascade recovery and reuse of waste lithium-ion batteries provided in the present application. The method for cascade recycling and reuse of waste lithium-ion batteries may, for example, include: collecting first characteristic information of waste lithium-ion batteries, dividing the waste lithium-ion batteries into different aging levels according to the first characteristic information, designing differentiated target discharge curves for batteries of each aging level, and performing precise adaptive discharge on waste lithium-ion batteries of each aging level according to the differentiated target discharge curves to obtain first discharge data; disassembling the discharged waste lithium-ion batteries to obtain positive electrode materials and negative electrode materials, extracting second characteristic information of the positive electrode materials and the negative electrode materials, dividing the positive electrode materials and the negative electrode materials into different performance levels according to the second characteristic information, and determining the recycling scheme corresponding to each performance level; recycling and regenerating the positive electrode materials and the negative electrode materials of each performance level according to the recycling scheme to obtain regenerated positive electrode materials and regenerated negative electrode materials; preparing new lithium-ion batteries using the regenerated positive electrode materials and the regenerated negative electrode materials, and performing charge and discharge tests on the new lithium-ion batteries to obtain second discharge data; comparing the first discharge data with the second discharge data to judge the feasibility of recycling the waste batteries.

[0258] Furthermore, the electronic device may also include a user interface. Of course, the architecture disclosed in the present invention is only exemplary, and when implementing different devices, one or more components in the electronic device disclosed in the present invention may be omitted according to actual needs.

[0259] Example 4

[0260] This embodiment discloses a computer-readable storage medium, on which computer-readable instructions are stored. When the computer-readable instructions are executed by a processor, the method for recycling and reusing waste lithium-ion batteries according to the embodiment of the present application described with reference to the above figures can be executed. The storage medium includes, but is not limited to, for example, volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and cache memory (cache), etc. Non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc.

[0261] In addition, according to the implementation mode of the present application, the process described in the above reference flowchart can be implemented as a computer software program. For example, the present application provides a non-transitory machine-readable storage medium, the non-transitory machine-readable storage medium stores machine-readable instructions, the machine-readable instructions can be executed by a processor to execute instructions corresponding to the method steps provided in the present application, for example: collecting first characteristic information of waste lithium-ion batteries, dividing the waste lithium-ion batteries into different aging levels according to the first characteristic information, designing differentiated target discharge curves for batteries of each aging level, performing precise adaptive discharge on waste lithium-ion batteries of each aging level according to the differentiated target discharge curves, and obtaining first discharge data; for the discharged waste lithium-ion batteries, The battery is disassembled to obtain positive electrode materials and negative electrode materials, and the second characteristic information of the positive electrode materials and the negative electrode materials is extracted. According to the second characteristic information, the positive electrode materials and the negative electrode materials are respectively divided into different performance levels, and the recycling scheme corresponding to each performance level is determined; the positive electrode materials and the negative electrode materials of each performance level are recycled and regenerated according to the recycling scheme to obtain regenerated positive electrode materials and regenerated negative electrode materials; the regenerated positive electrode materials and the regenerated negative electrode materials are used to prepare a new lithium-ion battery, and the new lithium-ion battery is charged and discharged to test to obtain the second discharge data; the first discharge data is compared with the second discharge data to judge the feasibility of recycling the waste battery. When the computer program is executed by the central processing unit (CPU), the above functions defined in the method of the present application are executed.

[0262] The methods, systems, and devices of the present application may be implemented in many ways. For example, the methods, systems, and devices of the present application may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above order of steps for the method is for illustration only, and the steps of the method of the present application are not limited to the order specifically described above unless otherwise specified. In addition, in some embodiments, the present application may also be implemented as programs recorded in a recording medium, which include machine-readable instructions for implementing the method according to the present application. Therefore, the present application also covers recording media storing programs for executing the method according to the present application.

[0263] In addition, the parts of the above-mentioned technical solutions provided in the embodiments of the present application that are consistent with the implementation principles of the corresponding technical solutions in the prior art are not described in detail to avoid excessive redundancy.

[0264] The specific implementation modes as described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation mode of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for recycling and reusing waste lithium-ion batteries, characterized in that: The method comprises: Collecting first characteristic information of waste lithium-ion batteries, dividing the waste lithium-ion batteries into different aging levels according to the first characteristic information, designing differentiated target discharge curves for batteries of each aging level, and performing precise adaptive discharge on the waste lithium-ion batteries of each aging level according to the differentiated target discharge curves to obtain first discharge data; Disassembling the discharged waste lithium-ion batteries to obtain positive electrode materials and negative electrode materials, extracting second characteristic information of the positive electrode materials and the negative electrode materials, classifying the positive electrode materials and the negative electrode materials into different performance levels according to the second characteristic information, and determining a recycling scheme corresponding to each performance level; recycling and regenerating the positive electrode materials and the negative electrode materials of each performance level according to the recycling scheme to obtain a regenerated positive electrode material and a regenerated negative electrode material; A new type of lithium-ion battery is prepared by using recycled positive electrode materials and recycled negative electrode materials, and a charge and discharge test is performed on the new type of lithium-ion battery to obtain second discharge data; the first discharge data is compared with the second discharge data to judge the feasibility of recycling the waste battery.

2. The method for recycling and reusing waste lithium-ion batteries according to claim 1, characterized in that: The first characteristic information includes a battery type parameter, a battery capacity parameter, a battery voltage parameter, and a battery usage time parameter; The method of classifying the waste lithium-ion batteries into different aging levels according to the first characteristic information includes: Based on the battery capacity parameters, calculate the capacity retention rate of waste lithium-ion batteries; Based on the battery voltage parameters, the voltage decay rate of the waste lithium-ion battery is calculated; Based on the battery usage time parameters, calculate the usage time coefficient of the waste lithium-ion battery; The battery aging coefficient is calculated by combining the capacity retention rate, voltage decay rate and usage time coefficient. L , the aging levels of used lithium-ion batteries are classified into L1, L2, L3, and L4; According to the battery aging coefficient θ L , the aging classification of waste lithium-ion batteries includes: When θ3≤θ L When ≤1, it is classified as L1 level, and θ3 is the third aging threshold; When θ2≤θ L <θ3, it is classified as L2, and θ2 is the second aging threshold; When θ1≤θ L <θ2, it is classified as L3, θ1 is the first aging threshold, θ3>θ2>θ1; When 0<θ L When <θ1, it is classified as L4.

3. The method for recycling and reusing waste lithium-ion batteries according to claim 2, characterized in that: The differentiated target discharge curves include an L1-level target discharge curve, an L2-level target discharge curve, an L3-level target discharge curve, and an L4-level target discharge curve; The differentiated target discharge curves designed for each aging level of the battery include: For L1 level batteries, a constant current discharge mode is used for discharge, the real-time voltage of the L1 level battery is marked as the first voltage, AM1 times the rated capacity is used as the discharge current, and the discharge is stopped when the first voltage drops to a preset first termination voltage, and the L1 level target discharge curve is obtained; For L2 level batteries, a segmented constant current discharge method is adopted, and the real-time voltage of the L2 level battery is marked as the second voltage. First, AM2 times the rated capacity is used as the discharge current. When the second voltage drops to the first critical voltage, the current is automatically switched to AM3 times the rated capacity as the discharge current. When the second voltage drops to the preset second termination voltage, the discharge is stopped to obtain the L2 level target discharge curve; wherein, AM1>AM2>AM3; For L3 level batteries, a two-stage discharge method of constant voltage and constant current is adopted. The real-time voltage of the L3 level battery is marked as the third voltage, and the real-time current of the L3 level battery is marked as the third current. The battery is discharged at a constant current first. When the third voltage drops to the second critical voltage, the battery is automatically switched to constant voltage discharge. When the third current drops to 0.05C, the discharge is stopped, and the target discharge curve of L3 level is obtained. For the L4-level battery, pulse discharge is used for discharging. The real-time voltage of the L4-level battery is marked as the fourth voltage. When the fourth voltage drops to the preset fourth cut-off voltage, the discharge stops, and the L4-level target discharge curve is obtained.

4. The method for recycling and reusing waste lithium-ion batteries according to claim 3, characterized in that: The first discharge data includes the first discharge specific capacity C1, the first cycle life N1, and the first self-discharge rate S1. Performing precise adaptive discharge on the waste lithium-ion batteries of each aging level to obtain the first discharge data including: According to the L1-level target discharge curve, performing precise adaptive discharge on the L1-level waste lithium-ion batteries to obtain the L1-level discharge data, and obtaining the first discharge specific capacity, the first cycle life, and the first self-discharge rate of the L1-level battery based on the L1-level discharge data. According to the L2-level target discharge curve, performing precise adaptive discharge on the L2-level waste lithium-ion batteries to obtain the L2-level discharge data, and obtaining the first discharge specific capacity, the first cycle life, and the first self-discharge rate of the L2-level battery based on the L2-level discharge data. According to the L3-level target discharge curve, performing precise adaptive discharge on the L3-level waste lithium-ion batteries to obtain the L3-level discharge data, and obtaining the first discharge specific capacity, the first cycle life, and the first self-discharge rate of the L3-level battery based on the L3-level discharge data. According to the L4-level target discharge curve, performing precise adaptive discharge on the L4-level waste lithium-ion batteries to obtain the L4-level discharge data, and obtaining the first discharge specific capacity, the first cycle life, and the first self-discharge rate of the L4-level battery based on the L4-level discharge data. Performing weighted average on the first discharge specific capacities of the L1, L2, L3, and L4-level batteries to obtain the first discharge specific capacity C1 in the overall first discharge data; performing weighted average on the first cycle lives of the L1, L2, L3, and L4-level batteries to obtain the first cycle life N1 in the overall first discharge data; performing weighted average on the first self-discharge rates of the L1, L2, L3, and L4-level batteries to obtain the first self-discharge rate S1 in the overall first discharge data.

5. The method for recycling and reusing waste lithium-ion batteries according to claim 1, characterized in that: The second characteristic information includes material morphology information, material composition information, and material structure information. The classifying the cathode material and the anode material into different performance levels according to the second characteristic information includes: Based on the material morphology information, calculating the morphology integrity index IM. Based on the material composition information, calculating the composition retention index IC. Based on the material structure information, calculating the structure integrity index IS. Performing weighted average on the morphology integrity index IM, the composition retention index IC, and the structure integrity index IS to obtain the material performance index IP. Classifying the cathode material and the anode material into different performance levels according to the material performance index IP.

6. The method for recycling and reusing waste lithium-ion batteries according to claim 5, characterized in that: The classifying the cathode material and the anode material into different performance levels according to the material performance index IP includes: When IP1 < IP ≤ 100%, it is classified as P1 level, where IP1 is the first performance threshold. When IP2 < IP ≤ IP1, it is classified as P2 level, where IP2 is the second performance threshold and IP1 > IP2. When 0 < IP ≤ IP2, it is classified as P3 level.

7. The method for recycling and reusing waste lithium-ion batteries according to claim 1, characterized in that: The second discharge data includes the second discharge specific capacity C2, the second cycle life N2, and the second self-discharge rate S2. The comparison of the first discharge data with the second discharge data to judge the feasibility of recycling the waste battery includes: Compare the first discharge specific capacity C1 with the second discharge specific capacity C2 to calculate the capacity recovery rate η of the new lithium-ion battery C ; Compare the first cycle life N1 with the second cycle life N2, and calculate the cycle life improvement rate η of the new lithium-ion battery N ; Compare the first self-discharge rate S1 with the second self-discharge rate S2, and calculate the self-discharge control coefficient η of the new lithium-ion battery S ; Comprehensive consideration of the capacity recovery rate η of new lithium-ion batteries C , cycle life improvement rate η N and self-discharge control coefficient η S , calculate the performance evaluation index P of the new lithium-ion battery R ; Set the performance index threshold θ P , if P R ≥θ P , it is determined that the recycling of used batteries is feasible.

8. A system for recycling and reusing waste lithium-ion batteries, which is used to implement the method for recycling and reusing waste lithium-ion batteries according to any one of claims 1 to 7, characterized in that: The system comprises: Aging grade classification module: used to collect the first characteristic information of the waste lithium-ion batteries, and classify the waste lithium-ion batteries into different aging grades according to the first characteristic information; Discharge module: used to design differentiated target discharge curves for batteries of each aging level, and to perform precise adaptive discharge on waste lithium-ion batteries of each aging level according to the differentiated target discharge curves to obtain first discharge data; Recycling module: used to disassemble the discharged waste lithium-ion batteries to obtain positive electrode materials and negative electrode materials, extract the second characteristic information of the positive electrode materials and the negative electrode materials, classify the positive electrode materials and the negative electrode materials into different performance levels according to the second characteristic information, and determine the recycling scheme corresponding to each performance level; according to the recycling scheme, recycle and regenerate the positive electrode materials and negative electrode materials of each performance level to obtain regenerated positive electrode materials and regenerated negative electrode materials; Regeneration module: used to prepare new lithium-ion batteries using recycled positive electrode materials and recycled negative electrode materials; Comparison module: used to perform charge and discharge tests on new lithium-ion batteries to obtain second discharge data; compare the first discharge data with the second discharge data to judge the feasibility of recycling used batteries.

9. An electronic device comprising a memory, a central processing unit, and a computer program stored in the memory and executable on the central processing unit, characterized in that: When the central processing unit executes the computer program, the method for cascade recovery and reuse of waste lithium-ion batteries described in any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which, when executed, implements the method for cascade recovery and reuse of waste lithium-ion batteries according to any one of claims 1 to 7.

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