Method and system for cascade recovery and reuse of waste lithium-ion batteries

Abstract

The present invention relates to the technical field of waste battery recycling and reuse, and discloses a method and system for the cascade recycling and reuse of waste lithium-ion batteries. The method first collects characteristic information of waste lithium-ion batteries, classifies them according to the degree of battery aging, designs differentiated discharge schemes for different levels, and obtains first discharge data through precise adaptive discharge. The waste batteries are then disassembled and classified according to the characteristics of the positive and negative electrode materials, and corresponding recycling and reuse schemes are determined to obtain regenerated positive and negative electrode materials. New batteries are prepared using the recycled materials and tested to obtain second discharge data. By comparing with the first discharge data, the feasibility of recycling the waste batteries is evaluated. The present invention can realize integrated processing of graded diagnosis, cascade discharge, and customized recycling based on the differentiated characteristics of waste batteries and materials, maximize the residual value of the batteries, and improve the level of resource utilization of waste batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of waste battery recycling and reuse, and more particularly to a method and system for cascade recycling 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, a core component of new energy vehicles, continues to grow rapidly. However, the lifespan of lithium-ion batteries is generally 3-8 years, and the large amount 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 resource utilization is a critical issue that needs to be addressed.

[0003] A Chinese patent with authorization publication number CN110176647B discloses a cascaded method for the utilization of waste lithium-ion battery negative electrode materials. This method uses the inverse relationship between capacity retention and the percentage of non-water-soluble lithium in the graphite negative electrode as the basis for classification. Different recycling processes are designed based on the different capacity retention rates of lithium batteries. Combined with electrochemical data such as retained capacity obtained during the cascaded recycling process of battery cells, a cascaded lithium extraction process is designed for waste batteries with varying degrees of aging. Li is extracted from the graphite in the waste lithium battery negative electrode using pure water leaching at room temperature, reducing recycling costs and increasing reuse value. However, this method primarily targets 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] Chinese patent application CN109346741B discloses a method for recycling waste lithium battery cathode materials. This method utilizes a unique three-phase, one-step reaction system, achieving high cobalt, nickel, manganese, and lithium leaching efficiencies in a single step for waste cathode materials of any composition. However, this method fails to account for the diverse properties of waste batteries and materials, applying the same treatment method to 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, and it is difficult to carry out graded treatment based on the differences in waste batteries and material properties, so as 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 cascade recovery and reuse of waste lithium-ion batteries, which can realize the integrated processing of graded diagnosis, cascade 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 for waste lithium-ion batteries include:

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

[0010] Disassembling 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 based on the second characteristic information, and determining recycling plans corresponding to each performance level; recycling and regenerating the positive electrode materials and negative electrode materials of each performance level according to the recycling plans to obtain regenerated positive electrode materials and regenerated negative electrode materials;

[0011] A new type of lithium-ion battery is prepared using recycled positive electrode materials and recycled negative electrode materials. The new type of lithium-ion battery is subjected to charge and discharge tests to obtain second discharge data. The first discharge data is compared with the second discharge data to evaluate the feasibility of recycling the used batteries.

[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] Classifying the used lithium-ion batteries into different aging levels based on the first characteristic information includes:

[0014] Calculate the capacity retention rate of used lithium-ion batteries based on battery capacity parameters;

[0015] Calculate the voltage decay rate of used lithium-ion batteries based on battery voltage parameters;

[0016] Calculate the service life coefficient of used lithium-ion batteries based on battery service life parameters;

[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 divided into L1, L2, L3, and L4;

[0018] According to the battery aging coefficient θ L , the aging grade 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 When <θ3, it is classified as L2 level, 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] Furthermore, 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;

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

[0025] For L1 level batteries, a constant current discharge method 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. When the first voltage drops to the preset first termination voltage, the discharge is stopped to obtain the L1 level target discharge curve.

[0026] For L2 batteries, a segmented constant current discharge method is adopted. The real-time voltage of the L2 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 target discharge curve; where AM1>AM2>AM3;

[0027] For L3 level batteries, a constant voltage and constant current two-stage discharge method 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 a constant voltage discharge. When the third current drops to 0.05C, the discharge is stopped to obtain the L3 level target discharge curve.

[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] Furthermore, 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 precise 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, perform precise adaptive discharge on the L1 waste lithium-ion battery to obtain L1 discharge data, and obtain the first discharge specific capacity, first cycle life and first self-discharge rate of the L1 battery based on the L1 discharge data;

[0032] According to the L2 target discharge curve, perform precise adaptive discharge on the L2 waste lithium-ion battery to obtain L2 discharge data, and obtain the first discharge specific capacity, first cycle life and first self-discharge rate of the L2 battery based on the L2 discharge data;

[0033] According to the L3 target discharge curve, perform precise adaptive discharge on the L3 waste lithium-ion battery to obtain L3 discharge data, and obtain the first discharge specific capacity, first cycle life and first self-discharge rate of the L3 battery based on the L3 discharge data;

[0034] According to the L4 target discharge curve, perform precise adaptive discharge on the L4 waste lithium-ion battery to obtain L4 discharge data, and obtain the first discharge specific capacity, first cycle life and first self-discharge rate of the L4 battery based on 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 rate 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 classification of the positive electrode material and the negative electrode material into different performance levels according to the second characteristic information includes:

[0038] Calculate the morphology integrity index IM based on the material morphology information;

[0039] Calculate the component retention index IC based on the material composition information;

[0040] Calculate the structural integrity index IS based on the material structure information;

[0041] The material performance index IP is obtained by weighted averaging the morphology integrity index IM, composition retention index IC and 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] Further, 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 level P1, where IP1 is the first performance threshold;

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

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

[0047] Further, 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 and 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 、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 ; Set the performance index threshold θ P , if P R ≥θ P , it is determined that the recycling of used batteries is feasible.

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

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

[0053] Discharge module: used to design differentiated target discharge curves for each aging level of batteries. Based on the differentiated target discharge curves, accurate adaptive discharge is performed on waste lithium-ion batteries of each aging level to obtain first discharge data.

[0054] Recycling module: used to disassemble discharged waste lithium-ion batteries to obtain positive electrode materials and negative electrode materials, extract second characteristic information of the positive electrode materials and negative electrode materials, classify the positive electrode materials and negative electrode materials into different performance levels based on the second characteristic information, and determine the recycling plan corresponding to each performance level; according to the recycling plan, the positive electrode materials and negative electrode materials of each performance level are recycled and regenerated 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 evaluate the feasibility of recycling used batteries.

[0057] An electronic device includes 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 recycling and reuse of waste lithium-ion batteries is implemented.

[0058] A computer-readable storage medium stores a computer program, which, when executed, implements the above-mentioned method for cascade recycling 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 scheme for recycling and reusing 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 cascade 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 utilization rate of residual value; 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 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 recovery, 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

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

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

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

[0068] Figure 7 This 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 provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0070] Example 1

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

[0072] Step S1000: collecting first characteristic information of used lithium-ion batteries, classifying the used lithium-ion batteries into different aging levels based on the first characteristic information, designing differentiated target discharge curves for batteries of each aging level, and performing precise adaptive discharge on the used lithium-ion batteries of each aging level based on 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, where the first characteristic information includes a battery type parameter, a battery capacity parameter, a battery voltage parameter, and a battery usage time parameter;

[0075] Specifically, step S1100 involves comprehensive information collection on used lithium-ion batteries, laying the foundation for subsequent classification and processing. The battery type reflects the battery's material system and structural characteristics. Common lithium-ion battery types include lithium iron phosphate batteries, ternary material batteries, and lithium manganese oxide batteries. Battery capacity is a key indicator of a battery's energy storage capacity, typically expressed in ampere-hours (Ah) or watt-hours (Wh). Different battery types vary significantly in their material systems, structural characteristics, and performance parameters, necessitating classification, identification, and processing. Battery capacity directly determines the battery's service life and range. Battery type and capacity information can be quickly obtained using barcode or radio frequency identification technology; this information is typically printed on the battery casing. A professional voltage meter is used to measure the battery's open circuit voltage and load voltage to obtain the battery voltage parameters. The open circuit voltage reflects the battery's state of charge, while the load voltage reflects the battery's output capacity. Together, these two determine the battery's remaining charge level. By reviewing usage records or process cards, the battery's service life can be determined. The length of service time is often closely related to the battery's aging. By collecting characteristic information from multiple dimensions and parameters, it is possible to evaluate battery status from perspectives such as capacity, voltage, and usage time, identify its potential value, and thus implement targeted policies based on its characteristics. This information is collected through a variety of methods such as barcode scanning, radio frequency identification, voltage measurement, and data query. Data is obtained through a combination of automatic recognition and manual entry to ensure comprehensive and accurate information, providing a reliable basis for tiered processing.

[0076] Step S1200: classifying the used 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, calculating the capacity retention rate of the used lithium-ion battery based on the battery capacity parameter as the first decision variable for aging grade classification;

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

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

[0081] Step S1240, 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 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 the battery is less than 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 When the battery is less than 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 its performance is severely degraded.

[0086] Specifically, step S1200 performs battery aging classification based on comprehensive collection of battery characteristic information, through quantitative analysis and comprehensive assessment. The capacity retention rate, which is the ratio of actual capacity to initial capacity, measures the degree of battery capacity decay relative to its initial state and provides a direct indicator of battery health. A higher capacity retention rate indicates less capacity decay and less severe battery aging. The voltage decay rate, which is the difference between the initial voltage and the actual voltage divided by the initial voltage, provides another perspective on the performance degradation caused by battery aging. A higher voltage decay rate indicates more severe degradation of the battery's active materials, a greater increase in internal resistance, and a more significant decrease in charge and discharge capacity. The usage duration coefficient, which is the actual usage time divided by the rated service life, reflects the actual usage intensity and aging risk of the battery. The longer the usage time, approaching or even exceeding the rated service life, the higher the probability of battery failure due to aging. Finally, the capacity retention rate, voltage decay rate, and usage duration coefficient can be comprehensively evaluated using a weighted summation method to classify the battery into four grades. L1 batteries have excellent performance across all indicators, exhibit the least degradation, and possess the highest residual value and potential for further utilization. L2 and L3 batteries are moderately aged and require further screening and repair. L4 batteries are severely aged and unusable, requiring only recycling. Scientific aging grading allows for rapid identification of battery status and value, providing a reference for decision-making in subsequent testing, repair, further utilization, and material recycling. This improves disposal efficiency, extends the battery value chain, and enables categorized policy implementation and targeted utilization.

[0087] The calculation of the battery aging coefficient by combining the capacity retention rate, voltage decay rate and 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 duration 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 Sensitivity to the aging coefficient. The larger the α value, the greater the V d Small changes in will lead to large changes in the aging coefficient;

[0094] β: Voltage decay rate threshold, indicating the critical point of voltage decay rate. d When β is exceeded, battery aging is accelerated;

[0095] γ: The influence coefficient of the usage time coefficient, which controls the usage time coefficient T u Sensitivity to the aging coefficient, the larger the γ value, the greater the T u Small changes in will lead to large changes in the aging coefficient;

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

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

[0098] In this formula, the capacity retention rate C r When θ increases, L Increase, indicating that the battery is in a healthier state; the voltage decay rate V d When θ increases, L Decrease, indicating that the battery is aging; the usage time coefficient T u When increasing: θ LA decrease indicates an increased risk of aging. The formula incorporates 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 through nonlinear transformation enables a more accurate assessment of battery status. By adjusting the parameters α, β, γ, and δ, customized assessments can be performed for different battery types and usage environments.

[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 squared 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 and validation sets to prevent overfitting.

[0107] Parameter determination: After obtaining the optimal parameter values, perform the final fitting on the entire data.

[0108] Step S1300: Designing differentiated target discharge curves for batteries of each aging level; 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;

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

[0110] Step S1310: Discharging the L1 battery using a constant current discharge method, marking the real-time voltage of the L1 battery as a first voltage, using AM1 times the rated capacity as the discharge current, and stopping the discharge when the first voltage drops to a preset first termination voltage, thereby obtaining an L1 target discharge curve;

[0111] Step S1320: For the L2 battery, a segmented constant current discharge method is adopted. The real-time voltage of the L2 battery is marked as a second voltage. First, AM2 times the rated capacity is used as the discharge current. When the second voltage drops to a first critical voltage, the current is automatically switched to AM3 times the rated capacity as the discharge current. When the second voltage drops to a preset second termination voltage, the discharge is stopped, thereby obtaining the L2 target discharge curve; wherein AM1>AM2>AM3;

[0112] Step S1330: For the L3 battery, a constant voltage and constant current two-stage discharge method is adopted. The real-time voltage of the L3 battery is marked as a third voltage, and the real-time current of the L3 battery is marked as a third current. The battery is first discharged at a constant current. When the third voltage drops to a second critical voltage, the battery is automatically switched to a constant voltage discharge. When the third current drops to 0.05C, the discharge is stopped, thereby obtaining an L3 target discharge curve.

[0113] In step S1340, a pulse discharge mode is used to discharge the L4 battery, and the real-time voltage of the L4 battery is marked as a fourth voltage. When the fourth voltage drops to a preset fourth termination voltage, the discharge is stopped to obtain an L4 target discharge curve.

[0114] Specifically, step S1300 comprehensively assesses the battery's aging status and designs differentiated discharge plans and target curves for batteries of varying aging levels. The core concept is "tailoring the approach to each battery's health," employing appropriate discharge strategies based on the battery's health status. This approach aims to fully release residual energy and improve resource efficiency, while also avoiding improper discharge methods that exacerbate battery aging and cause irreversible damage. By matching appropriate discharge rates, switching mechanisms, and termination conditions, a precise discharge model is constructed, generating differentiated target discharge curves to guide subsequent adaptive discharge control.

[0115] For L1-level batteries, due to their optimal health, 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 complete 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 already experienced mild aging, their capacity and voltage have declined, and the use of a single constant current rate is no longer appropriate. In order to strike a balance between efficient discharge and slowing down 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 (e.g., 3.0V), it is promptly switched to a lower AM3 rate (e.g., 0.2C) until the second voltage drops to the second termination voltage (e.g., 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, it is possible to ensure a certain discharge efficiency while maximally delaying capacity attenuation. 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 no longer 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 and 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 changes in the third current (i.e., the real-time current of the L3 level battery) are 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. In addition, too small a current may induce dangers such as dendrites. The two-stage discharge process, first constant current and then constant voltage, allows for quicker energy release when the battery is at a high charge. Later, the system switches to constant voltage mode, discharging at a low current under a regulated voltage to fully utilize the remaining capacity until the battery stabilizes. This effectively mitigates risks such as overcharge and over-discharge. This results in the L3 target discharge curve, guiding the automatic switching and precise control of the two-stage discharge.

[0118] For L4 level batteries, their aging is very serious, and their capacity and voltage decay are huge. Traditional continuous constant current or constant voltage discharge is no longer applicable and may cause safety hazards. Step S1340 adopts a pulse discharge mode, which reduces the continuous discharge stress and delays battery degradation through periodic short-term discharge and shelving. Control the decrease in the pulse current to the fourth voltage (i.e., the real-time voltage of the L4 level battery). When it drops to the fourth termination voltage (such as 2.0V), stop discharging. After standing for a period of time, pulse discharge is performed again. This cycle continues until the battery voltage stabilizes within a safe range. Make full use of the driving force generated during the pulse discharge process to intermittently promote the insertion and extraction 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 standing time, the energy release rate and charge and discharge stress can be flexibly controlled. While recovering as much energy as possible, irreversible damage such as electrolyte drying and electrode powdering caused by continuous discharge can be avoided. The L4 level target discharge curve is thus 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 both energy utilization and battery safety, and is usually determined based on the battery material system and aging characteristics. For example, for the ternary material system, it is recommended to set the termination voltage to 2.5-2.7V and the critical voltage 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 to 2.5-2.8V. The choice of discharge rate must take into account both the battery's 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 tailor-made discharge plan can achieve precise control and optimal matching of the discharge process while respecting individual battery differences, taking into account both resource recycling and battery health maintenance, maximizing the residual value of the battery and 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 is 3.2V, and the second critical voltage is 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. This demonstrates that differentiated discharge plans can fully account for the characteristics of different aging batteries, providing targeted solutions that maximize battery health while improving energy efficiency and extending their remaining lifespan. This creates favorable conditions for battery recycling and green remanufacturing. This precise discharge approach is not only technically feasible but also economically effective, possessing broad application prospects.

[0121] In the battery world, C is the unit of rated capacity. For example, if a battery has a capacity of 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 charge and discharge currents; the C rate can be used to uniformly describe the charge and discharge 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. They have 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 an even lower AM3 rate (such as 0.2C). This can ensure a certain discharge efficiency while reducing the impact and damage of the voltage drop on the electrode material.

[0129] The design of AM1>AM2>AM3 is based on consideration of battery health and a balance between discharge efficiency and battery protection. Higher discharge rates improve discharge efficiency, but also increase battery stress and accelerate battery aging. Appropriately reducing the discharge rate for batteries at varying degrees of aging can minimize battery aging while maintaining the necessary energy release efficiency and preserving its residual value.

[0130] Step S1400 , performing precise adaptive discharge on waste lithium-ion batteries of various aging levels according to differentiated target discharge curves 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, taking a weighted average of the first discharge specific capacities of the L1, L2, L3, and L4 level batteries to obtain the first discharge specific capacity in the overall first discharge data; taking a weighted average of the first cycle life of the L1, L2, L3, and L4 level batteries to obtain the first cycle life in the overall first discharge data; taking a weighted average of the first self-discharge rates of the 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 a battery can discharge per unit mass or volume, and is an important indicator for evaluating battery energy density. 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 greater the number of cycles, the longer the battery's service life. Self-discharge refers to the capacity loss caused by 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 greater the battery's ability to retain a charge.

[0138] Step S1400 is to implement precise 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 to release the residual energy 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 is calculated based on the L1 discharge data, that is, the discharge capacity per unit mass or volume of the L1 battery, in mAh / g or mAh / cm 3 By repeatedly charging and discharging at a constant current and recording the number of cycles, the first cycle life data for the L1 battery is obtained. After a period of rest, such as 30 days, the decrease in open-circuit voltage is measured to estimate the first self-discharge rate, which is the percentage of L1 battery capacity loss per unit time.

[0139] Based on the L2 target discharge curve, the L2 battery is subjected to segmented constant current adaptive discharge. The second voltage change is monitored in real time, and the current is automatically switched based on the first critical voltage. Discharge is stopped when the second voltage drops to the second termination voltage. L2 discharge data, including discharge capacity, discharge time, voltage, current, and critical point data, are recorded. Based on this L2 discharge data, the first discharge specific capacity of the L2 battery is calculated. The first cycle life of the L2 battery is obtained through a limited number of segmented charge and discharge cycles, such as 200. The first self-discharge rate of the L2 battery is tested at rest.

[0140] According to the L3 target discharge curve, perform constant voltage and constant current adaptive discharge on the L3 battery. First, discharge at constant current, monitor the change in the third voltage in real time, and automatically switch to constant voltage discharge when the third voltage drops to the second critical voltage. Monitor the change in the third current in real time, and stop discharging when the third current drops to 0.05C. Record the L3 discharge data such as discharge capacity, discharge time, voltage, and current. Based on the L3 discharge data, evaluate the first discharge specific capacity of the L3 battery. Use a small current such as 0.1C to perform 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. 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, cycle life testing 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 capacity of L1, L2, L3, and L4 level batteries is weighted averaged to obtain the overall first discharge specific capacity; the first cycle life of L1, L2, L3, and L4 level batteries is weighted averaged to obtain the overall first cycle life; the first self-discharge rate of L1, L2, L3, and L4 level batteries is weighted averaged to obtain the overall first self-discharge rate.

[0143] Unlike conventional simple and fast discharge, this method can dynamically adjust discharge parameters according to the real-time status of the battery, achieving 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 monitoring the first voltage change in real time, 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 without causing irreversible capacity loss due to overdischarge. For L2-level batteries, segmented constant current adaptive discharge can be implemented. By setting the first critical voltage and judging the downward trend of the second voltage, it automatically switches to a low-rate current, which can release more capacity and prevent electrode damage caused by voltage drops. For L3-level batteries, a constant voltage and constant current coordinated control strategy is adopted. The constant current is first maintained to the second critical voltage and then automatically switches to the constant voltage stage. The decay of the third current is monitored in real time until the current approaches zero and the discharge is terminated. This avoids the hazards of undervoltage and overvoltage and makes full 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 stabilizes within a safe range.

[0144] Throughout the discharge process, detailed records are collected of various battery parameters, including initial voltage, final voltage, average voltage, discharge capacity, average current, discharge time, and number of pulses. Discharge curves for batteries of different aging levels, including voltage and current over time, are also collected. Performance parameters such as discharge capacity, energy, and efficiency are also collected for batteries of different aging levels. Key characteristic points during the differentiated discharge process, such as voltage and current at each segment, and final voltage, are also collected. This provides a rich and comprehensive first-discharge dataset. This first-discharge dataset captures the complete discharge behavior of batteries of four aging levels under differentiated adaptive discharge, providing a crucial basis for comprehensively assessing the residual value of used batteries. In summary, this adaptive discharge method not only discharges battery charge quickly and efficiently, maximizing resource recovery, but also fully accounts for battery aging characteristics, avoiding secondary damage during discharge and preserving the battery's residual value. Through precise discharge and data accumulation, this approach not only supports cascade utilization and green remanufacturing, but also accumulates valuable experience for battery lifecycle management and health diagnostics.

[0145] Step S2000: disassembling 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 based on the second characteristic information, and determining a recycling plan 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 plan to obtain regenerated positive electrode materials and regenerated negative electrode materials;

[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 material oxidation or secondary contamination. 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 breakage. Vacuum suction can remove residual liquid to the maximum extent, which is beneficial for 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 degradation, the external manifestations and microscopic mechanisms of material aging and 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 degradation, 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 material microstructure; by comparing the evolution of the microstructure before and after degradation, the structural origin and internal mechanism of material aging and failure are revealed.

[0151] Material morphology information is primarily obtained through SEM, which visually demonstrates the microscopic morphology of the material surface, such as particle size, shape, and distribution, as well as morphological changes such as volume expansion, cracking, and pulverization caused by charge-discharge cycling, revealing the outward manifestations of material degradation. Material composition information is primarily obtained through XRD, XPS, and ICP-OES, which qualitatively and quantitatively analyze the material's phase composition, chemical valence state, elemental content, and chemical reactions such as phase transitions, dissolution, and deposition induced by the charge-discharge process, elucidating the chemical origins of material degradation. Material structural information is primarily obtained through TEM, Raman, and XAFS, which penetrate down to the lattice scale, characterizing microstructural parameters such as crystal structure, bond lengths and angles, and coordination number, as well as charge-discharge-induced structural distortion, disorder, and reconstruction, revealing the structural roots of material degradation. By systematically collecting and analyzing secondary characteristic information, we can establish the intrinsic correlation between material degradation and morphological, compositional, and structural evolution, and construct a comprehensive understanding of material degradation mechanisms. This provides 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: Classifying the positive electrode material and the negative electrode material into different performance levels based on the second characteristic information, and determining a recycling scheme corresponding to each performance level; recycling and regenerating the positive electrode material and the negative electrode material of each performance level according to the recycling scheme to obtain regenerated positive electrode material and 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 the 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 averaging on the morphology integrity index IM, the component retention index IC, and the structural integrity index IS to obtain a 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 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 pores 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. For example, for a certain batch of waste battery cathode materials, SEM analysis shows that the surface crack area ratio is 5% and the pore area ratio is 3%. Based on this, IM = 92% is calculated, indicating that the surface morphology of this material is relatively complete and the recycling value is high.

[0165] Calculation of the composition retention index IC: Analyze the elemental 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 shift and peak width change; the average grain size and distribution are calculated through TEM image analysis; the defect density of the material is quantitatively calculated in combination with XRD data. Combining the above structural parameters, a structural integrity index IS is constructed to quantitatively evaluate the degree of structural degradation of the material, which serves as the 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 certain 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 Increased 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 appropriate.

[0167] At the macroscopic level, the macroscopic integrity of a material is primarily reflected through its morphological information. The morphological integrity index (IM) is a weighted average of parameters such as the fracture ratio and degree of pulverization. It intuitively reflects the degree of physical damage sustained by the material during mechanical disassembly. A larger IM value indicates a more complete material morphology and better physical properties. At the microscopic level, the focus is on the material's chemical properties. The composition retention index (IC) is a comprehensive calculation of parameters such as the elemental content, stoichiometric ratio, and impurity content of the material's surface and bulk. The closer the IC value is to 100%, the more stable the material's chemical composition, the closer it is to its original state, and the higher its value. The structural integrity index (IS) takes into account both macroscopic and microstructure, and is evaluated through characterization data such as XRD patterns, lattice parameters, specific surface area, porosity, and agglomeration state. A larger IS indicates a higher integrity of the material in terms of crystal structure, pore structure, and specific surface area, more retained active sites, and superior electrochemical performance.

[0168] Finally, the three sub-indicators of IM, IC, and IS are summed up and averaged according to certain weights to obtain a comprehensive material performance index IP. IP is a multi-dimensional 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's various performance indicators are relatively excellent and have extremely high recycling value. They are classified as P1 and should be recycled first; when the IP is between IP2 (such as 70%) and IP1, the material's performance is slightly degraded but can still be used. They are classified as P2 and should be selectively recycled; and when the IP is lower than IP2, the material has been severely deteriorated and has a low recycling value. It is classified as P3 and it is recommended to be discarded or recycled.

[0169] P1-grade materials, due to their optimal morphology, composition, and structure, and performance index (IP) approaching 100%, offer the highest recycling value. Priority should be given to their direct recycling and reuse, where appropriate processing is required to re-formulate them into electrode materials for use in new battery production. P1-grade positive and negative electrode materials are first recovered separately, screened and cleaned to remove surface impurities, and then further sorted based on material type. 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 and airflow classification can be used for enrichment. The resulting high-purity P1-grade positive and negative electrode materials undergo surface modification and coating to fine-tune their properties, such as conductivity and cycle stability. For example, surface coating of the ternary positive electrode to create a core-shell structure can effectively suppress interfacial side reactions and improve rate performance. Appropriate doping of the graphite negative electrode can increase the initial coulombic efficiency and improve rate performance. The resulting P1-grade recycled cathode and anode materials exhibit regular morphology, controllable composition, and stable structure. Their overall performance rivals or even surpasses that of the original materials, allowing them to be directly used in battery electrode manufacturing, achieving cascade utilization. This method is simple, low-cost, and offers high added value, maximizing material performance and making it the preferred option for P1-grade material recycling.

[0170] For P2-grade materials, their morphology, composition, and structure have shown some degradation, and their IP performance index (IP) has declined, but remains above the threshold. These materials have potential for recycling and reuse, but require tailored treatment and differentiated treatment. Further identification based on material type and aging characteristics can prioritize high-value P2-grade materials for recycling, while refining and regeneration can be considered for those that cannot be directly reused. For example, for ternary cathode materials, if their morphology is not significantly damaged, their primary components remain intact, and their structure is generally stable, with only minor surface damage to the coating phase and residual alkali accumulation, methods such as de-coating and chemical cleaning can be used to remove surface impurities and restore bulk activity. After treatment, these materials can be appropriately coated and modified, and then mixed with P1-grade cathode materials to produce high-performance secondary battery cathodes. For graphite anodes, if their layered structure is largely intact, with only a thickened SEI film and residual electrolyte, high-temperature carbonization and chemical etching can be used to remove the accumulated passivation film and impurities, exposing a fresh graphite layer and restoring rapid charge and discharge capability. After treatment, mixing with a P1-grade negative electrode can produce a stable negative electrode material. However, for P2-grade materials with more severe morphological collapse, component dissolution, and structural collapse, direct physical recycling and reuse is less cost-effective. In this case, hydrometallurgical processes can be prioritized, using chemical methods to dissolve and precipitate to achieve recovery and resynthesis of material components. The resulting ternary precursor or negative electrode graphitized intermediate is then sintered and doped to prepare a stable recycled material. This allows the majority of the material components to be recycled, while harmful impurities can be removed, material composition can be regulated, and the crystal structure repaired, giving low-cost P2-grade materials a "new lease of life."

[0171] For P3-grade materials, their morphology, composition, and structure have undergone severe degradation, destroying their integrity beyond recognition. Their IP index is low, making their continued electrochemical use meaningless. However, as metal and carbon "ores," they still have recycling value. Therefore, metallurgical methods such as smelting and roasting should be employed. Melting and reduction at high temperatures directly precipitate the metal and carbonaceous raw materials. These materials can then be further processed into battery-grade metal salts and carbon materials, achieving further value creation. For example, for ternary cathodes, crushing and leaching are performed, followed by acid solution to fully dissolve the nickel, cobalt, and manganese to produce a metal ion solution. Extraction, crystallization, and sintering can produce high-purity metal salts such as nickel sulfate, cobalt sulfate, and manganese sulfate, which can then be used in downstream material synthesis. The residue is further roasted and activated to produce high-surface-area carbon powder, which can be used as a conductive filler. For graphite anodes, high-temperature pyrolysis undergoes reactions such as carbon deposition and graphitization, allowing for direct reduction to highly oriented graphite. This is accompanied by the vaporization and volatilization of impurities and the separation of ash, resulting in automatic purification. The resulting high-purity graphite, after crushing and screening, can be used in a variety of applications, including negative electrode conductive agents and thermal conductive fillers. While this "direct recycling" of P3-grade materials may not yield battery-grade materials, it achieves efficient separation and recycling of valuable elements, turning "waste" into valuable resources. Compared to end-of-life disposal methods such as landfill and incineration, this significantly reduces environmental impact and resource consumption, offering significant economic and social benefits.

[0172] In summary, differentiated recycling strategies should be adopted for waste battery materials of different performance levels. For P1-grade materials, direct physical reuse should be prioritized to preserve their original performance advantages to the greatest extent possible. For P2-grade materials, a tailored approach should be adopted, prioritizing high-value materials for recycling, while chemical recovery and resynthesis should be employed for materials that are difficult to directly utilize. For P3-grade materials, the focus should be on separating valuable elements and utilizing them as raw materials, achieving a cascaded recycling process through metallurgical smelting and reduction. This tiered recycling system fully matches material properties, leverages the expertise of each link, and maximizes benefits while efficiently transforming resources, contributing to a virtuous cycle for 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%, with higher values indicating more complete 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 retained features to overall features;

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

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

[0184] When w C or w P When L increases, the IM value will decrease, indicating that the integrity of the material is reduced and the recycling value is reduced; when L 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 the material. By quantifying various parameters, it can more accurately reflect the actual morphological state of the material. Based on different IM values, different recycling plans can be formulated to optimize resource utilization.

[0186] Step S3000: Prepare a new lithium-ion battery using the recycled positive electrode material and the recycled negative electrode material, perform a charge and discharge test on the new lithium-ion battery, and obtain second discharge data; compare the first discharge data with the second discharge data to evaluate the performance of the new lithium-ion battery, and then judge the feasibility of recycling the waste battery.

[0187] Furthermore, step S3000 includes:

[0188] Step S3100 uses recycled positive and negative electrode materials to prepare a new lithium-ion battery. Specifically, the recycled positive and negative electrode materials obtained in step S2000 are used to prepare the new battery, referencing the design parameters of existing commercial lithium-ion batteries, such as cell thickness, areal capacity, and N / P ratio. The positive electrode active material, conductive agent, and binder are uniformly mixed according to a predetermined mass ratio, such as 8:1:1, to produce a positive electrode slurry. The slurry is then evenly coated onto an aluminum foil current collector using a coating tool such as a doctor blade, with a thickness of 100-200 μm. After coating, the slurry is dried in an oven at 80°C for 2 hours to remove the solvent. After drying, the slurry is rolled using a roller press to a thickness of 50-80 μm, producing the new positive electrode. The negative electrode preparation is similar to the positive electrode, except that the current collector is replaced with copper foil, and the compacted thickness is smaller, approximately 30-50 μm. During battery assembly, the new positive and negative electrodes are separated by a separator to prevent direct contact and short circuits. Separators are commonly made of porous polypropylene, polyethylene, or other materials. A ceramic coating is applied to the separator, which is then rolled using a roller press. The electrodes and separator are stacked and inserted into the battery casing. After evacuation, an electrolyte consisting of a high-purity carbonate solvent and a lithium salt is injected. Finally, the battery is heat-sealed and the tabs are removed, producing the finished lithium-ion battery. The entire manufacturing process must be carried out in a dry, inert atmosphere, such as argon, to prevent contamination of the battery materials by oxygen and water vapor.

[0189] Using recycled materials extracted from used batteries to create new batteries not only conserves resources and shortens the battery manufacturing cycle, but also utilizes a manufacturing process that is essentially the same as conventional lithium-ion batteries, eliminating the need for redesigned production lines and facilitating industrial expansion. The processing properties, particle size, and morphology of the recycled materials should be as close as possible to those of the original materials. The purity and electrochemical properties of the recycled materials are key factors influencing the performance of the new battery. Process parameters for processes such as coating and roller pressing must be optimized to match the characteristics of the recycled materials. In short, new lithium-ion batteries must maximize the use of recycled materials while ensuring performance and lifespan, achieving a closed-loop recycling of used batteries.

[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, and self-discharge, through standardized charge and discharge tests, and objectively evaluate its energy storage performance and use value. The so-called standardized charge and discharge test means that the battery is repeatedly charged and discharged at a specified charge and discharge rate (such as 0.5C charge and discharge) under specific environmental conditions (such as temperature 25±2°C and relative humidity 45% to 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 is 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 electrical energy 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 cascade 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 deintercalation capacity.

[0193] The second cycle life refers to the number of charge and discharge cycles a new battery undergoes 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 battery's service life and cycle stability and is an important basis for judging battery durability. The longer the cycle life, the more charge and discharge cycles the battery can withstand without significant capacity loss, and the longer its service life. This is especially important for power batteries and energy storage batteries, as it determines the mileage and replacement cycle of electric vehicles, as well as the economy and reliability of peak and frequency regulation of the power grid. If the cycle life of a new battery significantly exceeds that of a conventional battery, it means that the materials obtained through 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 suppressing capacity decay mechanisms such as lattice collapse, structural collapse, and interface erosion during the cycle process, 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 ability of the battery, and is particularly critical for backup batteries and mobile devices. The lower the self-discharge rate, the longer the battery can maintain a high state of charge without obvious "power loss", thereby extending the storage period and reducing the frequency of maintenance. 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, optimization of surface coating, and rational use of additives, thereby reducing factors such as electrolyte decomposition and transition metal dissolution that induce increased self-discharge, allowing the battery to be charged for a long time.

[0195] Overall, if the new battery's specific capacity, cycle life, self-discharge and other indicators are significantly better than those of conventional batteries, it can be determined that the materials obtained through cascade utilization have a significant improvement in battery performance. On the one hand, the optimization of the recycled materials in terms of activity, conductivity, and structure has improved the specific capacity level and reduced polarization impedance, laying the material foundation for higher energy density and rate performance. On the other hand, the recycling process effectively removes impurity contamination, repairs lattice defects, and inhibits capacity decay factors such as electrolyte decomposition and metal dissolution, thereby significantly 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 meticulous disassembly, sorting, repair, and compounding, the structural integrity and electrochemical activity of the materials are restored to a certain extent, removing the "root cause" of performance decay and activating the material's potential, making it reusable in battery manufacturing and demonstrating excellent overall performance in actual charge and discharge 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 individual indicators such as specific capacity, but also achieved overall optimization in multiple performance aspects such as cycle, rate, and storage. This 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: Compare the first discharge data with the second discharge data to determine the feasibility of recycling the used 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: Compare the first cycle life N1 with the second cycle life N2 to calculate the cycle life improvement rate η of the new lithium-ion battery. N ;

[0200] Step S3330: Compare the first self-discharge rate S1 with the second self-discharge rate S2 to calculate 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: Set 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 it is to 100%, it indicates that the capacity of the new lithium-ion battery has recovered 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 compared to the old battery, and the longer the service life. S =(S1) / (S2); η S The larger the value is, 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 From the perspectives of capacity, lifespan, and self-discharge, quantitatively describe the degree of improvement in the performance of new lithium-ion batteries compared to old batteries. C ,η N ,η S The weighted sum of the three sub-indicators gives the quantitative score of the regeneration effect, which is 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 improvement of new lithium-ion batteries compared with old batteries, and the better the recycling effect. R When the battery exceeds a certain critical value (such as 85%), it can be considered that the waste battery is worthy of recycling for secondary utilization; and when P R When the recycling rate is 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, let's assume a batch of used ternary material batteries has an initial capacity of 2500mAh. After 300 cycles, the capacity drops to 1875mAh, with a self-discharge rate of 15% / month, making them no longer suitable for use. After regeneration, the capacity returns to 2400mAh, and under standard conditions, they can be stably cycled for more than 500 times, with a self-discharge rate of 5% / month. Based on this, we can calculate:

[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 the following by substituting into the calculation:

[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 significantly improved in all aspects. It has full value for cascade utilization and can be used for secondary applications such as energy storage and backup power.

[0211] This case study clearly demonstrates that scientifically evaluating the performance improvements of new lithium-ion batteries and establishing quantitative indicators can provide important evidence and reference for selecting recycling paths for used batteries and making decisions about their full lifecycle management. 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 recycling and reuse system based on embodiment 1, such as Figure 7 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 each aging level of batteries. Based on the differentiated target discharge curves, accurate adaptive discharge is performed on waste lithium-ion batteries of each aging level to obtain first discharge data.

[0216] Recycling module: used to disassemble discharged waste lithium-ion batteries to obtain positive electrode materials and negative electrode materials, extract second characteristic information of the positive electrode materials and negative electrode materials, classify the positive electrode materials and negative electrode materials into different performance levels based on the second characteristic information, and determine the recycling plan corresponding to each performance level; according to the recycling plan, the positive electrode materials and negative electrode materials of each performance level are recycled and regenerated 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 evaluate 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 classifying the used lithium-ion batteries into different aging levels based on the first characteristic information includes:

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

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

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

[0223] Step S1240, 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 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 the battery is less than 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 When the battery is less than 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 its performance is severely 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. Designing differentiated target discharge curves for each aging level of the battery includes:

[0229] Step S1310: Discharging the L1 battery using a constant current discharge method, marking the real-time voltage of the L1 battery as a first voltage, using AM1 times the rated capacity as the discharge current, and stopping the discharge when the first voltage drops to a preset first termination voltage, thereby obtaining an L1 target discharge curve;

[0230] Step S1320: For the L2 battery, a segmented constant current discharge method is adopted. The real-time voltage of the L2 battery is marked as a second voltage. First, AM2 times the rated capacity is used as the discharge current. When the second voltage drops to a first critical voltage, the current is automatically switched to AM3 times the rated capacity as the discharge current. When the second voltage drops to a preset second termination voltage, the discharge is stopped, thereby obtaining the L2 target discharge curve; wherein AM1>AM2>AM3;

[0231] Step S1330: For the L3 battery, a constant voltage and constant current two-stage discharge method is adopted. The real-time voltage of the L3 battery is marked as a third voltage, and the real-time current of the L3 battery is marked as a third current. The battery is first discharged at a constant current. When the third voltage drops to a second critical voltage, the battery is automatically switched to a constant voltage discharge. When the third current drops to 0.05C, the discharge is stopped, thereby obtaining an L3 target discharge curve.

[0232] In step S1340, a pulse discharge mode is used to discharge the L4 battery, and the real-time voltage of the L4 battery is marked as a fourth voltage. When the fourth voltage drops to a preset fourth termination voltage, the discharge is stopped to obtain an L4 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 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, taking a weighted average of the first discharge specific capacities of the L1, L2, L3, and L4 level batteries to obtain the first discharge specific capacity in the overall first discharge data; taking a weighted average of the first cycle life of the L1, L2, L3, and L4 level batteries to obtain the first cycle life in the overall first discharge data; taking a weighted average of the first self-discharge rates of the 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 classification of the positive electrode material and the negative electrode material into different performance levels based on the second characteristic information includes:

[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 structure 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 structure 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 classification of 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 is classified as grade P1, where IP1 is the first performance threshold;

[0247] When IP2 < IP ≤ IP1, the material performance is second and 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 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 comparison of the first discharge data with the second discharge data to evaluate the feasibility of the recycling of 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 C , the cycle life improvement rate η N and the self-discharge control coefficient η S of the new lithium-ion battery, calculate the performance evaluation index P R ;

[0254] Step S3350: Set 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 that may include one or more processors and one or more memories. The memories may store computer-readable code that, when executed by the one or more processors, may implement the above-described method for cascaded recycling and reuse of waste lithium-ion batteries.

[0257] The method or system according to the embodiments of the present application can also be implemented with the aid 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, input / output components, 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 recycling and reuse of waste lithium-ion batteries provided in this 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, classifying the waste lithium-ion batteries into different aging levels based on 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 based on 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 based on the second characteristic information, and determining a recycling plan 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 plan 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; and comparing the first discharge data with the second discharge data to evaluate the feasibility of recycling the waste batteries.

[0258] Furthermore, the electronic device may further 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 having computer-readable instructions stored thereon. 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, volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and cache memory. Non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc.

[0261] In addition, according to the embodiment of the present application, the process described with reference to the flowchart above can be implemented as a computer software program. For example, the present application provides a non-transitory machine-readable storage medium, wherein the non-transitory machine-readable storage medium stores machine-readable instructions, and 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, 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; and performing precise adaptive discharge on the discharged waste lithium-ion batteries. The battery is disassembled to obtain positive electrode materials and negative electrode materials, and second characteristic information of the positive electrode materials and negative electrode materials is extracted. Based on the second characteristic information, the positive electrode materials and negative electrode materials are respectively classified into different performance levels, and a recycling plan corresponding to each performance level is determined; the positive electrode materials and negative electrode materials of each performance level are recycled and regenerated according to the recycling plan to obtain regenerated positive electrode materials and regenerated negative electrode materials; a new lithium-ion battery is prepared using the regenerated positive electrode materials and regenerated negative electrode materials, and the new lithium-ion battery is subjected to charge and discharge tests to obtain second discharge data; the first discharge data is compared with the second discharge data to evaluate the feasibility of recycling the waste battery. When the computer program is executed by a central processing unit (CPU), the above functions defined in the method of the present application are performed.

[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 methods according to the present application. Therefore, the present application also covers recording media that store programs for executing the methods according to the present application.

[0263] In addition, the parts of the above 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 above-described specific embodiments further illustrate the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is merely a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection 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 the used lithium-ion batteries, the first characteristic information including a battery type parameter, a battery capacity parameter, a battery voltage parameter, and a battery usage time parameter; classifying the used lithium-ion batteries into different aging levels based on the first characteristic information, the aging levels being L1, L2, L3, and L4, where L1 indicates that the battery has essentially no aging, L2 indicates that the battery is slightly aged, L3 indicates that the battery is moderately aged, and L4 indicates that the battery is severely aged; designing a differentiated target discharge curve for the batteries of each aging level, and performing precise adaptive discharge on the used lithium-ion batteries of each aging level based on the differentiated target discharge curve to obtain first discharge data; The differentiated target discharge curves designed for each aging level of the battery include: For L1 level batteries, a constant current discharge method 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. When the first voltage drops to the preset first termination voltage, the discharge is stopped to obtain the L1 level target discharge curve. For L2 batteries, a segmented constant current discharge method is adopted. The real-time voltage of the L2 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 target discharge curve; where AM1>AM2>AM3; For L3 level batteries, a constant voltage and constant current two-stage discharge method 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 a constant voltage discharge. When the third current drops to 0.05C, the discharge is stopped to obtain the L3 level target discharge curve. For L4 level batteries, a pulse discharge method is used 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; Disassembling 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, wherein the second characteristic information includes material morphology information, material composition information, and material structure information; classifying the positive electrode materials and the negative electrode materials into different performance levels based on the second characteristic information, and determining a recycling plan corresponding to each performance level; and recycling and regenerating the positive electrode materials and the negative electrode materials of each performance level according to the recycling plan to obtain regenerated positive electrode materials and regenerated negative electrode materials; A new type of lithium-ion battery is prepared using recycled positive electrode materials and recycled negative electrode materials. The new type of lithium-ion battery is subjected to charge and discharge tests to obtain second discharge data. The first discharge data is compared with the second discharge data to evaluate the feasibility of recycling the used batteries.

2. The method for recycling and reusing waste lithium-ion batteries according to claim 1, wherein: Classifying the used lithium-ion batteries into different aging levels based on the first characteristic information includes: Calculate the capacity retention rate of used lithium-ion batteries based on battery capacity parameters; Calculate the voltage decay rate of used lithium-ion batteries based on battery voltage parameters; Calculate the usage duration coefficient of used lithium-ion batteries based on battery usage time parameters; The battery aging coefficient is calculated by combining the capacity retention rate, voltage decay rate and usage time coefficient. L , classify the aging levels of used lithium-ion batteries; According to the battery aging coefficient θ L , the aging grade 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 When <θ3, it is classified as L2 level, 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 1, wherein: 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 used lithium-ion batteries of each aging level to obtain the first discharge data includes: According to the L1-level target discharge curve, perform precise adaptive discharge on L1-level used lithium-ion batteries to obtain L1-level discharge data, and obtain the first discharge specific capacity, the first cycle life, and the first self-discharge rate of L1-level batteries based on the L1-level discharge data; According to the L2-level target discharge curve, perform precise adaptive discharge on L2-level used lithium-ion batteries to obtain L2-level discharge data, and obtain the first discharge specific capacity, the first cycle life, and the first self-discharge rate of L2-level batteries based on the L2-level discharge data; According to the L3-level target discharge curve, perform precise adaptive discharge on L3-level used lithium-ion batteries to obtain L3-level discharge data, and obtain the first discharge specific capacity, the first cycle life, and the first self-discharge rate of L3-level batteries based on the L3-level discharge data; According to the L4-level target discharge curve, perform precise adaptive discharge on L4-level used lithium-ion batteries to obtain L4-level discharge data, and obtain the first discharge specific capacity, the first cycle life, and the first self-discharge rate of L4-level batteries based on the L4-level discharge data; Perform weighted averaging on the first discharge specific capacities of L1, L2, L3, and L4-level batteries to obtain the first discharge specific capacity C1 in the overall first discharge data; perform weighted averaging on the first cycle lives of L1, L2, L3, and L4-level batteries to obtain the first cycle life N1 in the overall first discharge data; perform weighted averaging on the first self-discharge rates of L1, L2, L3, and L4-level batteries to obtain the first self-discharge rate S1 in the overall first discharge data.

4. The method for recycling and reusing waste lithium-ion batteries according to claim 1, wherein: The classifying the positive electrode material and the negative electrode material into different performance levels according to the second characteristic information includes: Calculate the morphology integrity index IM based on material morphology information; Calculate the composition retention index IC based on material composition information; Calculate the structure integrity index IS based on material structure information; Perform weighted averaging on the morphology integrity index IM, the composition retention index IC, and the structure integrity index IS to obtain the material performance index IP; Classify the positive electrode material and the negative electrode material into different performance levels according to the material performance index IP.

5. The method for recycling and reusing waste lithium-ion batteries according to claim 4, characterized in that: The classifying the positive electrode material and the negative electrode 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.

6. 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; Comparing the first discharge data with the second discharge data to judge the feasibility of recycling the used battery includes: Compare the first discharge specific capacity C1 and 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 and the second self-discharge rate S2 to calculate the self-discharge control coefficient η of the new lithium-ion battery S ; 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 , it is determined that the recycling of used batteries is feasible.

7. A waste lithium-ion battery cascade recovery and reuse system, which is used to implement the waste lithium-ion battery cascade recovery and reuse method according to any one of claims 1 to 6, 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 each aging level of batteries. Based on the differentiated target discharge curves, accurate adaptive discharge is performed on waste lithium-ion batteries of each aging level to obtain first discharge data. Recycling module: used to disassemble discharged waste lithium-ion batteries to obtain positive electrode materials and negative electrode materials, extract second characteristic information of the positive electrode materials and negative electrode materials, classify the positive electrode materials and negative electrode materials into different performance levels based on the second characteristic information, and determine the recycling plan corresponding to each performance level; according to the recycling plan, the positive electrode materials and negative electrode materials of each performance level are recycled and regenerated 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 evaluate the feasibility of recycling used batteries.

8. 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 according to any one of claims 1 to 6 is implemented.

9. 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 recycling and reuse of waste lithium-ion batteries according to any one of claims 1 to 6.

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