Lossless disassembling method for battery module based on low-temperature brittleness difference

Abstract

The invention relates to the technical field of waste battery recycling, in particular to a battery module lossless disassembling method based on low-temperature brittleness difference, which comprises the following steps: step 1, analyzing material brittleness and formulating a gradient cooling program; 2, local directional cooling and embrittlement control, wherein a low-temperature cooling medium is adopted to conduct directional spraying on the adhesive concentration area, and meanwhile the temperature of the metal current collector is maintained to be higher than the embrittlement temperature of the metal current collector through heat insulation protection; temperature distribution is monitored in real time, cooling parameters are dynamically adjusted, and it is ensured that a target material is completely embrittled; step 3, vibration separation and layered recovery: applying low-frequency vibration to the embrittled battery module to break the embrittled material layer; and sorting materials based on fragment size and density difference, and recovering the complete metal current collector. By means of the steps, it is guaranteed that materials are not damaged in the disassembling process, and lossless disassembling and efficient recycling of the battery module are achieved through accurate control and the efficient sorting process.

Description

Technical Field

[0001] The present invention relates to the technical field of waste battery recycling, and in particular to a non-destructive disassembly method of a battery module based on low-temperature brittleness differences. Background Art

[0002] With the rapid development of new energy vehicles and energy storage industries, the large-scale retirement of power batteries such as lithium-ion batteries has become a global challenge. Battery modules are usually composed of multiple layers of heterogeneous materials such as metal current collectors (such as aluminum foil, copper foil), polymer separators, electrode active materials and organic binders (such as PVDF). Their high bonding strength and complex structure make disassembly and recycling face major technical bottlenecks. Existing disassembly technologies have the following main defects: When the existing technology uses mechanical means such as cutting and crushing to forcibly separate, the metal current collector and polymer material have high toughness at room temperature, which can easily lead to material breakage and fragment mixing (such as aluminum foil and diaphragm fragments interweaving), which seriously reduces the purity of metal recovery. In addition, mechanical impact may damage the electrode active material and affect the direct recycling of positive and negative electrode materials; In addition, when the existing technology softens or decomposes the binder by heating (usually above 200°C), the high temperature will cause the crystal structure of the electrode material to be destroyed (such as the phase change of the ternary material), the electrolyte will volatilize and produce toxic gases (such as HF), and the energy consumption is extremely high. More seriously, the oxidation of the metal collector is aggravated at high temperature, and an oxide layer is formed on the surface, which increases the difficulty of subsequent metallurgical purification; Finally, when strong acid, strong alkali or organic solvent (such as NMP) is used to dissolve the binder, although the material separation can be achieved, the solvent residue will contaminate the electrode active material, and the waste liquid treatment cost accounts for more than 30% of the total recycling cost. In addition, the chemical method is corrosive to the metal current collector (such as the erosion of aluminum foil by acid), which causes the foil to be thinned or even perforated, making it difficult to meet the requirements of direct recycling; In addition, the packaging forms of power battery modules are diverse (such as cylindrical, square, and soft-pack), and the internal adhesive distribution and interlayer bonding strength vary significantly, further requiring disassembly technology to have dynamic adaptation capabilities. Summary of the invention

[0003] Based on the above purpose, the present invention provides a non-destructive disassembly method of a battery module based on low-temperature brittleness difference, comprising the following steps: Step 1: Material brittleness analysis and gradient cooling program formulation: Identify the types of materials that make up the battery module, including metal current collectors, polymer separators, and adhesives; The brittle transition temperature of each material is determined through low-temperature mechanical tests, and a material brittleness database is established; Based on the ranking of the embrittlement temperatures of various materials in the database, design a staged gradient cooling program to preferentially cool materials with higher embrittlement temperatures; Step 2: Localized directional cooling and embrittlement control: Use a low-temperature cooling medium to perform directional spraying on the adhesive concentration area, and at the same time maintain the temperature of the metal current collector above its embrittlement temperature through heat insulation protection; Real-time monitor the temperature distribution and dynamically adjust the cooling parameters to ensure that the target material is completely embrittled; Step 3: Vibration separation and layered recovery: Apply low-frequency vibration to the embrittled battery module to break the embrittled material layer; Sort materials based on the differences in fragment size and density, and recover the intact metal current collector.

[0004] Preferably, the identification of the battery module in step 1 includes: Perform X-ray tomography on the battery module to obtain the spatial distribution of each layer of material; Combine energy spectrum analysis to determine the material composition and match it with a preset material library; The adjustment process of the X-ray scanning parameters includes: Select the X-ray energy according to the material density difference to ensure clear boundaries between adjacent material layers; Adjust the scanning resolution based on the layer thickness range to avoid image overlap.

[0005] Preferably, the low-temperature mechanical test in step 1 includes: Place the material specimen in a temperature-controlled environment and gradually cool it at a preset cooling rate; Apply tensile or impact loads at each temperature point and record the fracture strength and deformation characteristics; Determine the embrittlement critical temperature according to the curve of fracture strength versus temperature; The determination process of the preset cooling rate includes: According to the specimen thickness and thermal conductivity, calculate the internal temperature gradient through heat conduction simulation; Use the temperature gradient not exceeding a set ratio as a constraint condition to inversely deduce the maximum allowable cooling rate.

[0006] Preferably, the design of the gradient cooling program in step 1 includes: Establish a geometric model of the battery module and assign thermal conductivity properties to each material; Simulate the temperature field distribution at different cooling rates through finite element analysis; Take the temperature field uniformity as the optimization goal and iteratively adjust the cooling rate and holding time.

[0007] Preferably, the control process of the directional spraying in step 2 includes: Obtain the surface temperature distribution of the battery module in real time through an infrared thermal imager; Calculate the injection angle and flow rate of the cooling medium according to the temperature distribution difference; Cover the heat insulation film on the metal current collector area, and the reflectivity of the heat insulation film is determined by matching the metal heat capacity and the surface radiation coefficient.

[0008] Preferably, the selection of the low-temperature cooling medium in step 2 includes: Select a medium with a boiling point lower than the embrittlement temperature according to the embrittlement temperature of the target material and the boiling point of the medium; Calculate the cooling efficiency through the matching relationship between the latent heat of vaporization of the medium and the heat capacity of the material; The calculation of the cooling efficiency includes: Calculate the total heat absorption required according to the heat capacity of the material and the target temperature drop; Combine the medium flow rate and the latent heat of vaporization to determine the heat absorption capacity per unit time.

[0009] Preferably, the determination of the parameters of the low-frequency vibration in step 3 includes: Calculate the vibration energy threshold according to the fracture strength and the interfacial bonding force of the embrittled material; Dynamically adjust the vibration frequency and amplitude based on the statistical results of the fragment size distribution. Specifically, it includes: using a laser particle size analyzer to collect the particle size data of the fragments in real time, classifying the particle size distribution into adhesive powder, separator fragments and metal foil, and calculating the real-time proportion of each type of fragment. When the proportion of the adhesive powder exceeds the preset powder generation threshold, according to the negative feedback relationship between the powder generation rate and the vibration amplitude, reduce the vibration amplitude proportionally to inhibit the generation of ultrafine particles. When the proportion of the intact sheet structure in the metal foil fragments is lower than the preset integrity standard, based on the elastic modulus characteristics of the metal current collector, gradually increase the vibration frequency to enhance the interlayer shear separation effect. By real-time monitoring the deformation characteristics of the metal fragments during the vibration process, combined with the plastic deformation limit of the metal material, dynamically correct the upper threshold of the vibration parameters; The adjustment relationship between the vibration amplitude and the powder proportion is established through a calibration experiment, and the integrity of the metal current collector is maintained as a constraint condition during the calibration process; The adjustment direction of the vibration frequency is determined based on the test results of the interfacial bonding strength between the separator and the metal layer, ensuring that the vibration energy is concentrated on the embrittled material layer.

[0010] Preferably, the process of sorting materials based on the fragment size and density difference in step 3 includes: Set the initial parameters of the air flow sorting device according to the fragment density and aerodynamic characteristics difference; Record the fragment movement trajectory through high-speed photography and analyze the separation critical velocity of fragments with different densities; Adjust the air flow angle and velocity distribution based on the critical velocity.

[0011] Preferably, the recovery of the complete metal current collector in step 3 specifically includes: Immerse the separated metal foil in a constant-temperature liquid, and make the residual electrode material fall off due to the difference in thermal expansion coefficients; Determine the liquid temperature according to the balance relationship between the interfacial stress and the adhesion force; Remove the micron-sized dust on the metal surface by electrostatic adsorption.

[0012] Preferably, the process of applying low-frequency vibration to the embrittled battery module in step 3 further includes: Set a pressure sensor on the surface of the vibration table to monitor the change of the interlayer separation force in real time; Judge the peeling state of the adhesive layer according to the separation force curve; Stop vibrating when the separation force drops to a preset threshold to avoid metal damage.

[0013] Advantages of the present invention: Through means such as precise temperature control, low-temperature embrittlement difference, directional cooling and vibration separation, the battery module can be disassembled efficiently and without damage, while ensuring the complete recovery of key materials. This non-destructive disassembly not only helps to improve the recovery efficiency, reduce resource waste, but also reduces environmental pollution, and has significant economic and environmental benefits. Description of the Drawings

[0014] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only those of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 It is the process flow chart of the method of the present invention; Figure 2 It is the process flow chart of the control process of the directional spraying in step 2 of the method of the present invention; Figure 3 It is the process flow chart of the process of sorting materials based on the difference in fragment size and density in step 3 of the method of the present invention. Detailed Embodiments

[0016] The present invention will be described in detail below in conjunction with the drawings and specific embodiments. At the same time, it should be noted here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments. For some well-known technologies, those skilled in the art can also adopt other alternative methods for implementation; and the drawings are only for more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0017] See also Figures 1 - 3 , an embodiment of the present invention provides a non-destructive disassembly method for battery modules based on low-temperature brittleness differences. In step 1, the brittle transition temperature of each material is determined by accurately identifying materials such as metal current collectors, polymer separators and adhesives in the battery module and conducting low-temperature mechanical tests. A material brittleness database is established to provide a scientific basis for subsequent low-temperature treatment. Based on this database, a phased gradient cooling program is designed to ensure that materials with higher brittle temperatures are cooled first to optimize the disassembly efficiency. The implementation effect of this stage can ensure that the embrittlement of the material occurs in the ideal temperature range during the disassembly process, avoid damage to the internal structure of the battery, and create the best conditions for the subsequent separation process.

[0018] In step 2, the low-temperature cooling medium is sprayed to the adhesive area in a directional manner. At the same time, the temperature of the metal current collector is kept above its embrittlement temperature through thermal insulation measures to avoid unnecessary embrittlement. By monitoring the temperature distribution in real time, the spray angle and flow rate of the cooling medium are dynamically adjusted to ensure that the adhesive area is completely embrittled. This process ensures the uniformity of the embrittlement effect by precisely controlling the cooling process, further ensuring that the disassembly process will not damage the important metal current collector material and ensure recycling efficiency.

[0019] In step 3, the embrittled battery module will be subjected to low-frequency vibration treatment, and the embrittled material layer will break under the action of vibration. Subsequently, the materials are sorted according to the size and density differences of the fragments, and finally the complete metal current collector is recovered. Through the control of low-frequency vibration, the damage to the battery material by excessive mechanical force is avoided, ensuring the efficiency and accuracy of the recycling process. In addition, the difference in fragment size and density allows the sorting process to efficiently and accurately recover the metal current collector, and other waste can be further processed, maximizing the efficiency of disassembly and recycling.

[0020] Step 1 provides a theoretical basis for subsequent cooling and vibration separation through brittleness analysis, step 2 controls the embrittlement process through local directional cooling, and step 3 achieves precise material separation and recycling through vibration and sorting. This series of steps complement each other, not only ensuring that the materials are not damaged during the disassembly process, but also achieving non-destructive disassembly and efficient recycling of battery modules through precise control and efficient sorting processes, which is of great significance to improving the recycling rate and reducing resource waste. At the same time, due to the efficient control and precise adjustment of each step, the overall solution has high environmental protection and economic benefits.

[0021] In a possible implementation, first, by performing X-ray tomography on the battery module, a three-dimensional spatial distribution map of each material layer within the battery module is obtained. X-ray tomography can non-destructively penetrate materials and provide internal structure information of each layer of material, enabling accurate positioning of the boundaries of each material during subsequent disassembly and avoiding misoperations or damage to important components. In this way, the positions, thicknesses of each layer of material in the battery module and the interfaces between materials can be identified, providing important basic data for subsequent cryogenic cooling and vibration separation.

[0022] After obtaining the spatial distribution data of the battery module, the composition of the materials is accurately determined by combining energy spectrum analysis (such as X-ray energy spectrum analysis). Through energy spectrum analysis, the elemental composition of each layer of material can be understood and matched with a preset material library to further confirm the material types. The process of matching with the material library can ensure the accuracy of the disassembly plan, and by identifying different materials, the most suitable cryogenic treatment procedure can be designed according to the embrittlement temperature differences of each material, avoiding material damage or incomplete embrittlement caused by inappropriate temperatures.

[0023] When performing X-ray tomography, the adjustment of parameters is crucial for the imaging quality. First, select appropriate X-ray energy according to the density differences of different materials to ensure that the boundaries of adjacent material layers are clearly visible and avoid blurred or overlapping scanning images caused by materials with similar densities. Second, based on the thickness range of each layer of material in the battery module, adjust the scanning resolution to ensure that the details of each layer of material are clearly presented and avoid inaccurate identification of material distribution caused by image overlap or insufficient resolution.

[0024] Through X-ray scanning and energy spectrum analysis, a comprehensive understanding of the internal distribution, material types and thickness of the battery module can be achieved. This not only improves the accuracy and efficiency during disassembly, but also reduces resource waste or equipment damage caused by improper disassembly. At the same time, by reasonably adjusting the parameters of X-ray scanning, the imaging quality and clarity are ensured, providing a scientific basis for the optimization of subsequent disassembly plans, avoiding possible misoperations during disassembly, and greatly enhancing the success rate and feasibility of battery module disassembly.

[0025] In a possible implementation, first, place the material specimen in a temperature-controlled environment and gradually cool it at a preset cooling rate. This process ensures that the specimen gradually cools to the required test temperature within a predetermined temperature range. By controlling the cooling rate, it can be ensured that the influence of temperature change on the material is uniform and controllable, thus avoiding measurement errors caused by uneven temperature gradients. The control of the cooling rate will directly affect the accuracy of the brittle transition point of the material, so it needs to be determined through precise simulation calculations and experimental verifications.

[0026] At each temperature point, a tensile or impact load is applied and the fracture strength and deformation characteristics of the material are recorded. This step is crucial as it directly measures the tensile strength, impact resistance, and deformation characteristics of the material at different temperatures. Through tensile or impact tests, the external forces that the battery module may face during actual disassembly can be simulated. During the test, recording the fracture strength and deformation characteristics can help clarify the brittle behavior of the material and determine its fracture resistance at different temperatures.

[0027] Through the relationship curve between the fracture strength and temperature change, the critical embrittlement temperature can be accurately determined. The critical embrittlement temperature is the critical point at which the material undergoes brittle fracture under low-temperature conditions and usually becomes more fragile as the temperature decreases. By using the experimental data to plot the curve of temperature versus fracture strength, the embrittlement temperature of the material can be clearly marked and provide a reference for the disassembly of the battery module. This temperature will serve as an important operating parameter during the subsequent low-temperature treatment process.

[0028] During the determination of the cooling rate, by analyzing the specimen thickness and thermal conductivity and combining with heat conduction simulation calculations, the temperature gradient of the material at different temperatures can be obtained. According to the heat conduction simulation calculations, it is crucial to ensure that the temperature gradient does not exceed the set ratio. Too fast a cooling rate will cause uneven temperature inside the material, affecting the embrittlement effect. Therefore, it is necessary to inversely deduce the maximum allowable cooling rate so that the temperature gradient remains within a reasonable range, thereby ensuring that the material can reach its embrittlement temperature evenly without generating uneven stress or cracking.

[0029] Through this low-temperature mechanical test, the brittle changes of the battery module material at different temperatures can be accurately evaluated, providing a key basis for disassembly. Reasonable control of the cooling rate ensures the uniformity of temperature change, helps to accurately obtain the critical embrittlement temperature, and avoids data errors caused by uneven cooling. Ultimately, a more efficient and safe disassembly method can be designed based on the critical embrittlement temperature, avoiding material damage caused by improper disassembly operations, improving the disassembly efficiency, and reducing risks. At the same time, the setting of the cooling rate based on simulation calculations makes the experimental process more scientific and controllable, and can ensure the non-destructiveness and high efficiency of the disassembly process to the greatest extent.

[0030] In a possible implementation, first, a geometric model of the battery module needs to be established to ensure that it can accurately reflect the shape, size, and material distribution of each part of the battery module. The establishment of the geometric model is the basis for subsequent temperature field analysis and cooling rate adjustment. When establishing the model, the thermal conductivity property is assigned to each material, and this step is very important because the thermal conductivity differences of different materials will directly affect the heat conduction process. By defining the thermal conductivity of each material, the heat flow distribution of the entire battery module at different cooling rates can be simulated, thereby providing data support for subsequent cooling rate optimization.

[0031] After establishing the geometric model of the battery module, the finite element analysis tool is used to simulate the temperature field distribution under different cooling rates. This step can predict the temperature changes of various parts of the battery module under various cooling rate conditions through numerical simulation. Finite element analysis can help discover temperature non-uniformity problems during the cooling process and analyze the differences in thermal responses of different materials during the cooling process. The uniformity of the temperature field is a key factor in controlling material embrittlement during low-temperature disassembly. The simulation process can effectively identify potential temperature gradient problems and provide a decision-making basis for optimizing the cooling rate and insulation time.

[0032] Taking the uniformity of the temperature field as the optimization goal, the cooling rate and holding time are adjusted iteratively based on finite element analysis. This step aims to ensure a uniform temperature distribution throughout the battery module through multiple optimization adjustments. Too fast or too slow a cooling rate will lead to excessive temperature gradients, which will affect the brittle transition and disassembly effect of the material. Therefore, through multiple adjustments and optimizations, it is ensured that the temperature changes of each part are balanced to avoid local overcooling or overheating.

[0033] In one possible implementation, first, an infrared thermal imager is used to monitor the temperature distribution on the surface of the battery module in real time. This process uses infrared technology to obtain temperature information at various locations on the surface of the battery module, ensuring that the dynamic situation of temperature changes of the battery module during the cooling process can be grasped in a timely manner. The infrared thermal imager can accurately display the distribution of heat on the surface of the battery module, helping operators to find areas with uneven temperatures, especially areas that need to be cooled. The temperature data obtained will serve as the basis for subsequent calculations of the injection angle and flow rate of the cooling medium.

[0034] By analyzing the temperature distribution data obtained in real time, the areas with large temperature differences on the battery module surface are identified. These areas with large temperature differences are usually the parts of the battery module that are prone to brittle fracture. Then, based on these temperature distribution differences, the injection angle and flow rate of the cooling medium are calculated to ensure that the cooling medium can accurately act on the high-temperature areas and achieve the expected cooling effect. In this process, it is necessary to consider the precise control of the injection angle to ensure that the cooling medium can be evenly sprayed on the surface of the battery module, and the injection flow rate needs to be adjusted according to the cooling needs to avoid cooling too fast or too slow.

[0035] To further optimize the cooling effect, especially in the area of the metal current collector, its surface can be covered with a heat-insulating film. The function of the heat-insulating film is to reduce the heat loss that may occur when the cooling medium is in direct contact with the metal current collector and to reduce the risk of excessive cooling. The reflectivity of the heat-insulating film is precisely determined according to the heat capacity of the metal current collector and the surface radiation coefficient. The heat capacity determines the heat absorption capacity of the metal current collector, while the surface radiation coefficient affects the heat radiation effect of the metal surface. By optimizing the reflectivity of the heat-insulating film, more efficient temperature control can be achieved, making the cooling process more precise and avoiding thermal stress caused by too rapid cooling in the area of the metal current collector.

[0036] Through the real-time monitoring of an infrared thermal imager, the temperature changes of the battery module can be dynamically tracked, the cooling requirements can be accurately judged, and excessive or insufficient cooling can be avoided. By calculating the injection angle and flow rate, it can be ensured that the cooling medium acts precisely on the area to be cooled, thereby reducing the material brittleness difference caused by the temperature difference. Further, by optimizing the reflectivity of the heat-insulating film in the area of the metal current collector, not only the cooling efficiency is improved, but also the structural damage caused by excessive cooling is avoided. Overall, this process greatly improves the accuracy and safety of the disassembly of the battery module, ensures the efficient progress of damage-free disassembly, and reduces the damage risk that may occur during the disassembly process.

[0037] In a possible implementation, in this step, first, the cooling medium is selected according to the embrittlement temperature of the target material and the boiling point of the cooling medium. The embrittlement temperature refers to the temperature at which the material begins to become brittle and may crack at low temperatures, while the boiling point of the cooling medium is the temperature at which the medium changes from a liquid state to a gaseous state. To avoid premature embrittlement of the material during the cooling process, the boiling point of the selected cooling medium must be lower than the embrittlement temperature of the target material. In this way, when the cooling medium contacts the surface of the material, the temperature of the material surface can be effectively reduced, ensuring that the material brittleness difference can play a role within a safe range, thereby achieving the effect of damage-free disassembly.

[0038] The calculation of the cooling efficiency is completed by matching the latent heat of vaporization of the cooling medium with the heat capacity of the material. The latent heat of vaporization of the cooling medium refers to the heat required for the medium to change from a liquid state to a gaseous state, and this process can effectively take away the heat on the surface of the material, thereby reducing the material temperature. The heat capacity of the material determines the temperature change range during the heat absorption process. By matching the two, the heat absorption capacity of the cooling medium per unit time can be evaluated.

[0039] The core of the cooling process is to ensure that the material is cooled below the embrittlement temperature. Based on the heat capacity of the target material and the target temperature drop, the total heat absorption required can be calculated. The relationship between heat capacity and temperature difference determines the amount of heat that the material can absorb within a certain period of time. Therefore, the purpose of calculating the total heat absorption is to ensure that the cooling process can remove sufficient heat so that the material will not be damaged due to overheating during the disassembly process.

[0040] Finally, by combining the flow rate of the cooling medium and the latent heat of vaporization, the heat absorption capacity of the cooling medium per unit time is calculated. The greater the flow rate, the more heat the cooling medium can carry, thereby improving the cooling efficiency. The higher the latent heat of vaporization, the greater the amount of heat that can be removed per unit time. Therefore, the matching relationship between the flow rate and the latent heat is crucial for achieving efficient cooling.

[0041] By selecting a suitable cooling medium, damage to other materials within the battery module due to overcooling can be effectively avoided, and at the same time, failure during the disassembly process caused by insufficient cooling can also be prevented. Precise calculation of the cooling efficiency enables the cooling process to achieve the maximum temperature drop effect in the shortest time, thereby improving the disassembly efficiency and reducing the damage risk. In addition, by controlling the matching relationship between the medium flow rate and the latent heat of vaporization, the uniformity and efficiency of the cooling process are ensured, further enhancing the non-destructiveness and safety of the disassembly process.

[0042] In one possible implementation, first, the threshold value of the vibration energy needs to be calculated based on the fracture strength and interlayer bonding force of the embrittled material. The fracture strength of the embrittled material refers to the maximum stress intensity that the material can withstand when subjected to external forces. Beyond this intensity, the material will fracture or break. The interlayer bonding force, on the other hand, determines the degree of adhesion between different layers. At low temperatures, the embrittlement degree of the material increases. Therefore, for embrittled materials, a suitable vibration energy threshold must be accurately calculated to ensure that the vibration energy reaches a sufficient level to fracture or peel the material without causing excessive damage.

[0043] After obtaining the vibration energy threshold, the next step is to dynamically adjust the vibration frequency and amplitude based on the statistical results of the fragment size distribution. The vibration frequency and amplitude determine the energy characteristics of the vibration wave transmission, and the adjustment of these parameters is crucial for controlling the fragment size distribution. By dynamically adjusting the vibration frequency and amplitude, it can be ensured that fragments of different sizes can be effectively processed, avoiding unnecessary damage caused by excessive or insufficient vibration.

[0044] To achieve precise adjustment of vibration parameters, it is first necessary to collect fragment particle size data in real time through a laser particle size analyzer. The laser particle size analyzer can provide high-precision particle size data to help monitor the fragment size distribution during the disassembly process. Through the analysis of the data, the fragments can be classified into adhesive powder, separator fragments, and metal foil, and classified and processed according to the proportion of each type of fragment. The statistically obtained fragment size distribution can reflect the fragmentation characteristics of the materials during the disassembly process, thereby further optimizing the adjustment of vibration parameters.

[0045] According to the particle size distribution results, the fragments are classified into different categories, such as: adhesive powder, separator fragments, and metal foil. The proportion of each type of fragment will help adjust the frequency and amplitude of vibration to ensure that different types of materials can be properly processed. For example, metal foil may require a higher frequency of vibration, while adhesive powder may require a lower amplitude of vibration to be effectively decomposed.

[0046] By precisely controlling the vibration energy and dynamically adjusting the frequency and amplitude, the target material can be effectively fragmented while reducing the impact on other sensitive materials. The statistics and classification of fragment sizes make the adjustment of vibration parameters more scientific and reasonable, avoiding the problem of overly small fragments or damage to other non-target materials caused by excessive vibration. Generally speaking, this process can effectively improve the disassembly efficiency and ensure the implementation of non-destructive disassembly, reducing both energy waste and improving the integrity of material recycling.

[0047] In a possible implementation, first, according to the differences in the density and aerodynamic characteristics of the fragments, the initial parameters of the air classification device are set. The air classification device utilizes the characteristics of air flow to separate fragments of different densities by adjusting parameters such as the angle and speed of the air flow. Since fragments with a larger density will experience greater resistance in the air flow, while fragments with a smaller density will fly farther or higher in the air flow, by precisely setting the initial parameters of the air flow, effective separation of fragments of different densities can be achieved.

[0048] To accurately understand the motion characteristics of the fragments, it is necessary to record the motion trajectories of the fragments in the air flow through high-speed photography. High-speed photography can capture the details of the fragment motion, thereby analyzing the motion speeds, flight trajectories of fragments of different densities, and their interactions with the air flow. This process is crucial because it can provide real-time data to help analyze the critical speed of fragment separation. The critical speed refers to the minimum speed at which fragments of a certain density start to be separated by the air flow, and this speed determines whether the fragments can be effectively separated.

[0049] By analyzing the high-speed camera data, the separation critical velocity of debris with different densities can be accurately calculated. For debris of different materials and densities, their flying speeds and trajectories will vary. Therefore, an accurate critical velocity is the key to ensuring efficient sorting. Through this analysis, it can be determined what speed each type of debris needs to reach to be separated in the airflow.

[0050] Based on the analyzed critical velocity, further adjust the angle and velocity distribution of the airflow to ensure that debris of different densities can be separated as expected. Adjusting the angle and velocity distribution of the airflow can control the acting force of the airflow on the debris, so that the lighter debris is carried away by the airflow, while the heavier debris will fall into the predetermined collection area. By optimizing the airflow distribution, the sorting accuracy and efficiency can be improved, enabling various types of debris to be optimally processed.

[0051] Through precise airflow sorting technology, the density differences and aerodynamic property differences of the debris are effectively utilized to ensure efficient separation of the debris. By adjusting the angle and velocity distribution of the airflow, debris of different densities can be fully sorted, and debris of different materials can be collected separately, providing convenience for subsequent material recycling and processing. Through this process, the sorting efficiency can be maximized, material mixing can be reduced, and the overall effect and recovery rate of the disassembly process can be improved. In addition, this method can provide customized disassembly solutions for different types of battery modules, significantly enhancing the adaptability and universality of the non-destructive disassembly technology.

[0052] In a possible implementation, first, immerse the metal foil separated by airflow sorting or other means into a constant-temperature liquid. This process utilizes the difference in the coefficient of thermal expansion, using the temperature change to trigger the expansion effect of different materials, thereby promoting the detachment of the metal foil from the electrode material. Due to their different coefficients of thermal expansion, the metal current collector and the electrode material will exhibit different expansion behaviors after heating. The metal foil usually has a lower coefficient of thermal expansion, while the electrode material (such as the active material) expands to a greater extent after heating, resulting in a weakened connection force between the two, and the electrode material can fall off smoothly.

[0053] To ensure the efficiency of this process, the temperature of the liquid must be precisely controlled. In this step, the optimal temperature of the liquid is determined by calculating the balance relationship between the interfacial stress and the adhesion force. The interfacial stress refers to the interaction force between the metal foil and the electrode material due to their different physical properties, while the adhesion force is the adhesion between the two. By adjusting the liquid temperature, at a specific temperature, the adhesion force between the two is reduced, and the electrode material can fall off smoothly, thereby recovering the complete metal foil. This process can ensure the integrity of the metal current collector is not damaged while removing the attached electrode material.

[0054] There may be micron-sized dust attached to the metal surface. Such dust not only affects the subsequent recycling and reuse of the metal but may also affect the performance of the current collector. Therefore, the next step is to utilize the principle of electrostatic adsorption to remove the dust on the metal surface through specific electrostatic equipment. Electrostatic adsorption can utilize the charge attraction between the dust particles and the metal surface to remove the tiny particles from the metal surface, thereby ensuring the cleanliness of the metal surface. This process can not only effectively remove the surface dust but also prevent the interference of the dust on the subsequent steps, ensuring the purity of the metal surface.

[0055] Through a series of delicate operations such as temperature-controlled liquid, interfacial stress, and electrostatic adsorption, not only the metal recycling efficiency is improved, but also the integrity of the metal material is maximally protected, laying a foundation for the non-destructive disassembly of the battery module and the efficient recycling of materials.

[0056] In a possible implementation, first, a pressure sensor is equipped on the vibration table to monitor the change of the interlayer separation force of the battery module in real time. By applying low-frequency vibration, the adhesive layer or other bonding layers in the battery module will gradually be subjected to stress, and the pressure sensor can accurately capture the change of the interlayer separation force. As the low-frequency vibration continues, the peeling force of the adhesive gradually changes, and the data monitored by the pressure sensor can provide a basis for subsequent control.

[0057] The data of the interlayer separation force provided by the pressure sensor in real time forms a separation force curve after being processed. According to the change trend of the separation force curve, the peeling state of the adhesive layer can be judged. Generally, when the adhesive layer is close to complete peeling, the separation force will decrease significantly. If it is observed that the separation force gradually tends to be stable or decreases during this process, it indicates that the adhesive layer has been completely peeled, and continuing to apply vibration may cause damage to the metal material. Therefore, the change of the separation force curve becomes an important basis for judging the termination timing of vibration.

[0058] According to the preset separation force threshold, when the separation force curve drops to this threshold, it means that the peeling of the adhesive layer has been completed, and continuing to apply low-frequency vibration will not help further separation but may cause damage to the metal current collector or other materials. Therefore, when the separation force monitored by the sensor drops to this threshold, the system will automatically stop the vibration to ensure that the metal material is not damaged and avoid the physical damage that may be caused by excessive vibration.

[0059] The above steps are interconnected through precise monitoring and control. First, the interlayer separation force is monitored in real time by the pressure sensor on the vibration table, and a separation force curve is formed based on these data. Then, the peeling state of the adhesive layer is judged according to the separation force curve. Finally, when the separation force reaches the preset threshold, the vibration is automatically stopped. This series of steps are closely linked to ensure the effectiveness of the vibration process and the integrity of the metal material.

[0060] The change in the interlayer separation force is monitored by a pressure sensor, and the peeling state is judged according to the separation force curve, so that the stopping timing of the low-frequency vibration can be accurately controlled, thereby ensuring the non-destructive disassembly of the battery module. This method not only improves the disassembly efficiency, but also maximally protects the integrity of the metal current collector, ensuring the high value of the recycled materials and the safety of the operation process.

[0061] This invention covers any alternatives, modifications, equivalent methods and solutions made on the essence and scope of this invention. To enable the public to have a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments of this invention. However, those skilled in the art can fully understand this invention even without the description of these details. In addition, well-known methods, processes, procedures, components and circuits, etc. are not described in detail to avoid unnecessary confusion to the essence of this invention.

[0062] The above are only the preferred embodiments of this invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of this invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of this invention.

Claims

1. A non-destructive disassembly method for a battery module based on the difference in low-temperature brittleness, characterized in that, It includes the following steps: Step 1: Brittle analysis of materials and formulation of gradient cooling program: Identify the types of constituent materials of the battery module, including metal current collectors, polymer separators, and adhesives; Determine the brittle transition temperature points of each material through low-temperature mechanical tests and establish a material brittleness database; Based on the ranking of the embrittlement temperatures of the materials in the database, design a staged gradient cooling program to preferentially cool the materials with higher embrittlement temperatures; Step 2: Local directional cooling and embrittlement control: Directly spray a low-temperature cooling medium on the adhesive concentration area, and at the same time maintain the temperature of the metal current collector above its embrittlement temperature through heat insulation protection; Real-time monitor the temperature distribution and dynamically adjust the cooling parameters to ensure that the target material is completely embrittled; Step 3: Vibration separation and layered recovery: Apply low-frequency vibration to the embrittled battery module to break the embrittled material layer; Sort materials based on the differences in fragment size and density, and recover the intact metal current collector.

2. The non-destructive disassembly method of a battery module based on the difference in low-temperature brittleness according to claim 1, wherein The identification of the battery module described in Step 1 includes: Perform X-ray tomography on the battery module to obtain the spatial distribution of each layer of materials; Determine the material composition by combining energy spectrum analysis and match it with the preset material library; The adjustment process of the X-ray scanning parameters includes: Select the X-ray energy according to the material density difference to ensure clear boundaries between adjacent material layers; Adjust the scanning resolution based on the layer thickness range to avoid image overlap.

3. A non-destructive disassembly method for a battery module based on low-temperature brittleness difference according to claim 1, characterized in that, The low-temperature mechanical test described in Step 1 includes: Place the material specimen in a temperature-controlled environment and gradually cool it at a preset cooling rate; Apply tensile or impact loads at each temperature point and record the fracture strength and deformation characteristics; Determine the embrittlement critical temperature according to the change curve of the fracture strength with temperature; The determination process of the preset cooling rate includes: Calculate the internal temperature gradient through heat conduction simulation according to the specimen thickness and thermal conductivity; Use the temperature gradient not exceeding the set ratio as a constraint condition to inversely deduce the maximum allowable cooling rate.

4. A method for nondestructive disassembly of a battery module based on the difference in low-temperature brittleness according to claim 1, characterized in that, The design of the gradient cooling program described in Step 1 includes: Establish a geometric model of the battery module and assign thermal conductivity properties to each material; Simulate the temperature field distribution at different cooling rates through finite element analysis; Take the temperature field uniformity as the optimization goal and iteratively adjust the cooling rate and holding time.

5. The non-destructive disassembly method of battery modules based on low-temperature brittleness difference according to claim 1, characterized in that: The control process of the directional spraying described in Step 2 includes: Real-time obtain the surface temperature distribution of the battery module through an infrared thermal imager; Calculate the spraying angle and flow rate of the cooling medium according to the temperature distribution difference; Cover the metal current collector area with a heat insulation film, and the reflectivity of the heat insulation film is determined by matching the metal heat capacity and surface radiation coefficient.

6. The non-destructive disassembly method of battery modules based on low-temperature brittleness difference according to claim 1, characterized in that: The selection of the low-temperature cooling medium described in Step 2 includes: Select a medium with a boiling point lower than the embrittlement temperature according to the embrittlement temperature of the target material and the boiling point of the medium; Calculate the cooling efficiency through the matching relationship between the latent heat of vaporization of the medium and the heat capacity of the material; The calculation of the cooling efficiency includes: Calculate the total heat absorption required according to the heat capacity of the material and the target temperature drop; Combine the medium flow rate and the latent heat of vaporization to determine the heat absorption capacity per unit time.

7. A non-destructive disassembly method for a battery module based on the difference in low-temperature brittleness according to claim 1, characterized in that, The determination of the parameters of the low-frequency vibration described in Step 3 includes: Calculate the vibration energy threshold according to the fracture strength and interfacial bonding force of the embrittled material; Dynamically adjust the vibration frequency and amplitude based on the statistical results of the fragment size distribution, specifically including: using a laser particle size analyzer to collect the fragment particle size data in real time, classifying the particle size distribution into binder powder, separator fragments, and metal foil, and calculating the real-time proportion of each type of fragment. When the proportion of the binder powder exceeds the preset powder generation threshold, according to the negative feedback relationship between the powder generation rate and the vibration amplitude, reduce the vibration amplitude proportionally to inhibit the generation of ultrafine particles. When the proportion of the intact sheet structure in the metal foil fragments is lower than the preset integrity standard, based on the elastic modulus characteristics of the metal current collector, gradually increase the vibration frequency to enhance the interlayer shear separation effect. By real-time monitoring the deformation characteristics of the metal fragments during vibration and combining with the plastic deformation limit of the metal material, dynamically correct the upper threshold of the vibration parameters; The adjustment relationship between the vibration amplitude and the powder proportion is established through a calibration experiment, and the integrity of the metal current collector is maintained as a constraint condition during the calibration process; The adjustment direction of the vibration frequency is determined based on the test results of the interfacial bonding strength between the separator and the metal layer to ensure that the vibration energy is concentrated in the embrittled material layer.

8. A non-destructive disassembly method for a battery module based on the difference in low-temperature brittleness according to claim 1, characterized in that, The process of sorting materials based on the fragment size and density differences in step 3 includes: Set the initial parameters of the air classification device according to the fragment density and aerodynamic characteristics differences; Record the fragment movement trajectories through high-speed photography and analyze the separation critical velocities of fragments with different densities; Adjust the air flow angle and velocity distribution based on the critical velocity as a benchmark.

9. A method for non-destructive disassembly of a battery module based on the difference in low-temperature brittleness according to claim 1, wherein The specific process of recovering the intact metal current collector in step 3 includes: Immerse the separated metal foil in a constant-temperature liquid to make the residual electrode material fall off through the difference in thermal expansion coefficients; Determine the liquid temperature according to the balance relationship between the interfacial stress and the adhesion force; Remove the micron-level dust on the metal surface through electrostatic adsorption.

10. A non-destructive disassembly method for a battery module based on the difference in low-temperature brittleness according to claim 1, characterized in that, The process of applying low-frequency vibration to the embrittled battery module in step 3 further includes: Set a pressure sensor on the surface of the vibration table to monitor the change of the interlayer separation force in real time; Judge the peeling state of the binder layer according to the separation force curve; Stop the vibration when the separation force drops to the preset threshold to avoid metal damage.

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