Lithium battery lithium extraction device and lithium battery lithium extraction method

Abstract

The invention provides a lithium battery lithium extraction device and a lithium battery lithium extraction method.The lithium battery lithium extraction device comprises a feeding module, a pyrolysis stripping module, a separation and collection module and an ultrasonic piezoelectric lithium extraction module, and lithium battery pole pieces are conveyed to the pyrolysis stripping module through the feeding module; the pyrolysis stripping module is used for pyrolyzing a lithium battery pole piece to strip lithium iron phosphate positive electrode powder through coordination and cooperation of the heating and auxiliary air system and the turnover mechanism, and the separation and collection module is used for separating the stripped lithium iron phosphate positive electrode powder from an aluminum current collector and collecting the lithium iron phosphate positive electrode powder. The ultrasonic piezoelectric lithium extraction module is used for triggering a piezoelectric effect through ultrasonic waves, micro-vibration is generated and acts on the lithium iron phosphate positive electrode powder, and lithium ions are dissociated from the lithium iron phosphate positive electrode powder. The lithium iron phosphate positive electrode powder can be stripped in a pyrolysis mode, lithium ions are dissociated from the lithium iron phosphate positive electrode powder in combination with an ultrasonic piezoelectric mode, and the lithium iron phosphate positive electrode powder stripping method has the advantages of being rapid and thorough in lithium iron phosphate positive electrode powder stripping, good in lithium extraction effect, high in lithium extraction efficiency and the like.

Description

Technical Field

[0001] The present disclosure relates to the technical field of lithium battery processing, and particularly to a lithium extraction device and a lithium extraction method for lithium batteries. Background Art

[0002] In recent years, with the development of the new energy vehicle and energy storage industries, the usage of lithium batteries has increased significantly. Correspondingly, the number of retired lithium batteries has also increased substantially. Implementing material recycling and regeneration technologies for retired lithium batteries will help prevent and control the pollution of waste batteries, relieve the shortage pressure of battery materials (such as lithium), and promote the healthy development of China's lithium battery industry.

[0003] Taking lithium iron phosphate batteries as an example, in the recycling and processing of retired lithium iron phosphate batteries, how to effectively separate lithium iron phosphate cathode powder from aluminum current collectors and efficiently extract lithium elements from lithium iron phosphate is one of the key technical problems. In related technologies, mechanical crushing methods and chemical leaching methods are mostly used. However, the mechanical crushing method and chemical leaching method often have problems such as complex operation, low efficiency, and heavy pollution, and it is difficult to meet the industrial requirements. More importantly, it is difficult to completely separate the cathode powder and the current collector by using the mechanical crushing method, while a large amount of acid-base solutions need to be used in the chemical leaching method, which brings environmental pollution risks and increases the processing cost. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the related technologies, the purpose of the present disclosure is to provide a lithium extraction device and a lithium extraction method for lithium batteries to solve various problems in the related technologies.

[0005] The first aspect of the present disclosure provides a lithium extraction device for lithium batteries, including: A feeding module, including a feeding chamber and a feeding mechanism, and feeding the lithium battery electrode sheets to be processed into the feeding chamber through the feeding mechanism; A pyrolysis and stripping module, including a pyrolysis and stripping chamber, a heating and auxiliary air system, and a turning mechanism. The pyrolysis and stripping chamber is communicated with the feeding chamber, and the heating and auxiliary air system cooperates with the turning mechanism to strip the lithium iron phosphate cathode powder and aluminum current collectors from the lithium battery electrode sheets. Among them, the heating and auxiliary air system is used to provide high-temperature hot air to the pyrolysis and stripping chamber to decompose the binder in the lithium battery electrode sheets, and the turning mechanism is used to turn the lithium battery electrode sheets in the stripping chamber; A cooling and preliminary separation module, used to cool and preliminarily separate the mixed material of the stripped lithium iron phosphate cathode powder and aluminum current collectors to obtain a material containing lithium iron phosphate cathode powder; A separation and collection module, used to separate and collect the separated lithium iron phosphate cathode powder from the material containing lithium iron phosphate cathode powder obtained in the cooling and preliminary separation module; and The ultrasonic piezoelectric lithium extraction module is used to generate micro-vibrations through the ultrasonic-induced piezoelectric effect and act on the lithium iron phosphate cathode powder to dissociate lithium ions therefrom.

[0006] In some examples of the first aspect, in the feeding module, the feeding mechanism includes a spiral feeding rod and a feeding guide plate. The feeding rod is arranged along the feeding cavity. Driven by a driving motor, the feeding rod transfers the lithium battery electrode sheet to be processed from the input end of the feeding cavity to the output end of the feeding cavity. The feeding guide plate is arranged at the output end of the feeding cavity and is used to guide the lithium battery electrode sheet into the pyrolysis and stripping cavity of the pyrolysis and stripping module.

[0007] In some examples of the first aspect, the heating and auxiliary air system includes: a heating plate and a hot air tank. The heating plate is used to provide a high-temperature heat source and generate high-temperature hot air. The hot air tank is used to introduce the high-temperature hot air generated by the heating plate into the pyrolysis and stripping cavity to pyrolyze the lithium battery electrode sheet transported in the pyrolysis and stripping cavity, and control the inlet air flow rate of the high-temperature hot air flowing through the hot air tank through an internal air valve and an air guiding plate.

[0008] In some examples of the first aspect, the binder is polyvinylidene fluoride (PVDF), and the temperature range of the high-temperature hot air is 450 °C to 650 °C.

[0009] In some examples of the first aspect, to control the temperature of the high-temperature hot air and match the corresponding inlet air flow rate, the corresponding relationship between the inlet air flow rate and temperature of the high-temperature hot air is set under different feeding flow rates of the lithium battery electrode sheet: When the feeding flow rate is 0.5 kg / min to 1 kg / min, the inlet air flow rate is (T - 450) / 450 + 1 m³ / s, where T is the temperature of the high-temperature hot air; When the feeding flow rate is 1 kg / min to 10 kg / min, the inlet air flow rate is (T - 450) / 450 + 1.5 m³ / s, where T is the temperature of the high-temperature hot air; When the feeding flow rate is 10 kg / min to 30 kg / min, the inlet air flow rate is (T - 450) / 450 + 2 m³ / s, where T is the temperature of the high-temperature hot air.

[0010] In some examples of the first aspect, the flipping mechanism includes a drum, a drum driving unit, and a drum feeding chute. The drum is provided with a discharge hopper. Driven by the drum driving unit, the drum flips to flip the lithium battery electrode sheet during pyrolysis. The drum feeding chute adopts a spiral structure, driving the lithium battery electrode sheet to gradually advance in the drum and being continuously affected by high-temperature pyrolysis and air flow during flipping, accelerating the decomposition of the binder.

[0011] In certain examples of the first aspect, the lithium extraction device for lithium batteries is further configured with a gas distribution system, the gas distribution system includes an intake pipeline and a gas distribution pipeline, a protective gas is introduced through the intake pipeline and transported to the gas distribution pipeline, and the protective gas is evenly distributed in the feeding chamber of the feeding module and the pyrolysis stripping chamber of the pyrolysis stripping module through the gas distribution holes on the gas distribution pipeline.

[0012] In certain examples of the first aspect, the cooling and preliminary separation module includes: a cooling chamber, a blowing component, a suction hopper, and a main air duct. By inputting low-temperature air flow into the cooling chamber, the physical properties of the lithium iron phosphate cathode powder and the aluminum current collector change, facilitating separation. The suction hopper is located above the cooling chamber and communicates with the main air duct, and the blowing component is used to blow the lithium iron phosphate cathode powder into the suction hopper and the main air duct.

[0013] In certain examples of the first aspect, the separation and collection module includes: an analyzer and a linear sieve. Among them, the analyzer is used to separate the lithium iron phosphate cathode powder and the aluminum current collector, and the linear sieve is used to further separate the lithium iron phosphate cathode powder separated from the analyzer.

[0014] In certain examples of the first aspect, the ultrasonic piezoelectric lithium extraction module includes: an ultrasonic piezoelectric reaction chamber, an injector, an ultrasonic generator, an ultrasonic transducer, and a piezoelectric generator. The piezoelectric generator uses a surface piezoelectric coating. The injector is used to inject liquid into the ultrasonic piezoelectric reaction chamber. The ultrasonic generator transmits ultrasonic waves to the piezoelectric generator through the ultrasonic transducer, exciting the piezoelectric generator to generate a piezoelectric effect, directly acting on the lithium iron phosphate cathode powder in the liquid phase, triggering the release of lithium ions, gradually dissociating and dissolving to form a lithium solution. In certain examples of the first aspect, the lithium extraction device for lithium batteries further includes: an automatic loading system located at the front end of the feeding module, and / or a lithium solution screening module located at the rear end of the ultrasonic piezoelectric lithium extraction module.

[0015] The second aspect of the present disclosure provides a method for extracting lithium from lithium batteries, which is applied to the lithium extraction device for lithium batteries as described above. The method for extracting lithium from lithium batteries includes the following steps: Using the feeding module to send the lithium battery electrode sheets to be processed into the pyrolysis stripping module; Using the pyrolysis stripping module to provide high-temperature hot air through the heating and auxiliary air system, pyrolyzing the lithium battery electrode sheets to strip out the lithium iron phosphate cathode powder, and flipping the lithium battery electrode sheets during the pyrolysis process through a flipping mechanism to accelerate the stripping of the lithium iron phosphate cathode powder; Using the cooling and preliminary separation module to cool and preliminarily separate the mixed material of the stripped lithium iron phosphate cathode powder and the aluminum current collector to obtain a material containing the lithium iron phosphate cathode powder; Using a separation and collection module to separate a material containing lithium iron phosphate cathode powder and collect the separated lithium iron phosphate cathode powder; and Using an ultrasonic piezoelectric lithium extraction module to generate a piezoelectric effect through ultrasonic waves, produce micro-vibrations and act on the lithium iron phosphate cathode powder to dissociate lithium ions therefrom.

[0016] As described above, the lithium extraction device and method for lithium extraction from lithium batteries provided by the present disclosure are used for lithium extraction operations on lithium batteries. The lithium extraction device for lithium batteries includes: a feeding module, a pyrolysis and stripping module, a separation and collection module, and an ultrasonic piezoelectric lithium extraction module. Using the feeding module to convey the lithium battery electrode sheet to be processed to the pyrolysis and stripping module, and using the pyrolysis and stripping module to pyrolyze the lithium battery electrode sheet through the coordinated cooperation of a heating and auxiliary air system and a flipping mechanism to strip out the lithium iron phosphate cathode powder, using the separation and collection module to separate the lithium iron phosphate cathode powder and the aluminum current collector stripped out in the pyrolysis and stripping module and collect the lithium iron phosphate cathode powder, and using the ultrasonic piezoelectric lithium extraction module to generate a piezoelectric effect through ultrasonic waves, produce micro-vibrations and act on the lithium iron phosphate cathode powder to dissociate lithium ions therefrom. The present disclosure can strip out the lithium iron phosphate cathode powder by pyrolysis and dissociate lithium ions from the lithium iron phosphate cathode powder in combination with the ultrasonic piezoelectric method. Compared with the related technologies using mechanical crushing methods or chemical leaching methods, it has the advantages of fast and thorough stripping of the lithium iron phosphate cathode powder, good lithium extraction effect and high lithium extraction efficiency. Description of the Drawings

[0017] Figure 1 Shown is a structural block diagram of the lithium extraction device for lithium batteries of the present disclosure.

[0018] Figure 2 and Figure 3 Shown is a schematic structural diagram of the lithium extraction device for lithium batteries of the present disclosure in an embodiment.

[0019] Figure 4 Shown is a front view of the heating and auxiliary air system in an embodiment.

[0020] Figure 5 Shown is a side view of the heating and auxiliary air system in an embodiment.

[0021] Figure 6 Shown is a side view of the hot air tank in the heating and auxiliary air system in an embodiment.

[0022] Figure 7 Shown is a schematic diagram of thermogravimetric analysis and differential thermal analysis using polyvinylidene fluoride PVDF as a binder.

[0023] Figure 8 Shown is a front view of the flipping mechanism in an embodiment.

[0024] Figure 9Shown is a side view of the flipping mechanism in an embodiment.

[0025] Figure 10 Shown is a schematic flow chart of the method for extracting lithium from lithium batteries in an embodiment. Detailed implementation manners

[0026] The following uses specific examples to illustrate the implementation manners of the present disclosure. Those skilled in the art can easily understand other advantages and effects of the present disclosure from the information disclosed in the present disclosure. The present disclosure can also be implemented or applied through other different specific implementation manners. Various details in the present disclosure can also be modified or changed according to different viewpoints and application scenarios without departing from the spirit of the present disclosure. It should be noted that, without conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0027] The following takes the drawings as a reference and details the embodiments of the present disclosure so that those skilled in the art to which the present disclosure pertains can easily implement it. The present disclosure can be embodied in many different forms and is not limited to the embodiments described herein.

[0028] In the description of the present disclosure, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics represented in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. Moreover, the specific features, structures, materials, or characteristics represented can be combined in a suitable manner in any one or a group of embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples represented in the present disclosure and the features of different embodiments or examples.

[0029] In addition, the terms "first" and "second" are only used for the purpose of indication and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of such features. In the description of the present disclosure, the meaning of "a group" is two or more, unless otherwise specifically defined.

[0030] To clearly illustrate the present disclosure, devices irrelevant to the description are omitted, and the same or similar components throughout the specification are given the same reference numerals.

[0031] Throughout the specification, unless otherwise clearly defined and limited, terms such as "provided with" and "connected" shall be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In addition, when it is said that a certain device "comprises" a certain constituent element, unless there is a particularly contrary record, it does not exclude other constituent elements, but means that other constituent elements can also be included.

[0033] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0034] Although in some examples the terms first, second, etc. are used herein to represent various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, the first interface and the second interface, etc. are indicated. Furthermore, as used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context indicates otherwise. It should be further understood that the terms "comprising", "including" indicate the presence of the described features, steps, operations, elements, modules, items, kinds, and / or groups, but do not exclude the presence, occurrence or addition of one or a group of other features, steps, operations, elements, modules, items, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or meaning any one or any combination. Therefore, "A, B or C" or "A, B and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A, B and C". An exception to this definition only occurs when the combination of elements, functions, steps or operations are mutually exclusive in some way.

[0035] The technical terms used herein are only for referring to specific embodiments and are not intended to limit the present disclosure. The singular forms used herein also include the plural forms as long as the statements do not clearly indicate the contrary meaning. The meaning of "including" used in the specification is to embody specific characteristics, regions, integers, steps, operations, elements and / or components, and does not exclude the existence or addition of other characteristics, regions, integers, steps, operations, elements and / or components.

[0036] Although not defined differently, including technical terms and scientific terms used herein, all terms have the same meaning as generally understood by those skilled in the technical field to which this disclosure pertains. Terms defined in commonly used dictionaries are additionally interpreted to have meanings consistent with relevant technical literature and the currently presented messages. Unless otherwise defined, they shall not be over-interpreted as ideal or overly formulaic meanings.

[0037] In related technologies involving lithium extraction from lithium batteries, mechanical crushing methods and chemical leaching methods are often used. However, mechanical crushing methods and chemical leaching methods often have problems such as complex operations, low efficiency, and heavy pollution. For example, it is difficult to completely separate the cathode powder and the current collector using the mechanical crushing method, while the chemical leaching method requires the use of a large amount of acid-base solutions, bringing environmental pollution risks and increasing processing costs.

[0038] In view of this, in the embodiments of the present disclosure, a lithium extraction device and a lithium extraction method for lithium batteries are provided. The lithium iron phosphate cathode powder is peeled off by pyrolysis, and lithium ions are dissociated from the lithium iron phosphate cathode powder by combining the ultrasonic piezoelectric method. Compared with the related technologies using mechanical crushing methods or chemical leaching methods, it has the advantages of rapid and complete peeling of the lithium iron phosphate cathode powder, good lithium extraction effect, and high lithium extraction efficiency.

[0039] The embodiments of the present disclosure provide a lithium extraction device for lithium batteries, including: a feeding module, a pyrolysis peeling module, a separation and collection module, and an ultrasonic piezoelectric lithium extraction module. The feeding module is used to feed the lithium battery electrode sheet to be processed into the pyrolysis peeling module. The pyrolysis peeling module pyrolyzes the lithium battery electrode sheet through the coordinated cooperation of a heating and auxiliary air system and a flipping mechanism to peel off the lithium iron phosphate cathode powder. The separation and collection module separates the peeled lithium iron phosphate cathode powder and the aluminum current collector and collects the lithium iron phosphate cathode powder. The ultrasonic piezoelectric lithium extraction module dissociates lithium ions from the lithium iron phosphate cathode powder by using the ultrasonic piezoelectric method.

[0040] Please refer to Figures 1 to 3 wherein, Figure 1 shows the structural block diagram of the lithium extraction device for lithium batteries of the present disclosure, Figure 2 and Figure 3 shows the structural schematic diagram of the lithium extraction device for lithium batteries of the present disclosure in one embodiment.

[0041] As Figures 1 to 3 shown, the lithium extraction device for lithium batteries of the present disclosure may include: a feeding module 11, a pyrolysis peeling module 13, a cooling and preliminary separation module 15, a separation and collection module 17, and an ultrasonic piezoelectric lithium extraction module 19.

[0042] The feeding module 11 is used to realize the feeding of the lithium battery electrode sheet to be processed.

[0043] In some embodiments, the feeding module 11 may include a feeding chamber 111 and a feeding mechanism.

[0044] The feeding chamber 111 may be horizontally arranged and have an input end and an output end opposite to the input end. Exemplarily, the feeding chamber 111 is integrally cylindrical.

[0045] The feeding mechanism may include a spiral feeding rod 113 with a driving motor and a feeding guide plate. The spiral feeding rod 113 is provided with continuous spiral feeding blades along its length direction. The spiral feeding rod 113 is arranged along the length direction of the feeding chamber 111. The head end of the spiral feeding rod 113 is arranged at the feeding end of the feeding chamber 111, and the feeding guide plate may be arranged at the end of the spiral feeding rod 113. In some embodiments, the feeding guide plate is designed to have a certain guiding inclination angle, which is beneficial to guiding the lithium battery electrode sheet into the pyrolysis and stripping module 13.

[0046] The spiral feeding rod 113 rotates under the drive of the driving motor, and is used to transfer the lithium battery electrode sheet to be processed from the input end of the feeding chamber 111 to the output end of the feeding chamber 111 and guide the lithium battery electrode sheet into the pyrolysis and stripping module through the feeding guide plate. Among them, the design of the spiral feeding rod 113 needs to ensure that the lithium battery electrode sheet enters the next step at an appropriate speed and streamline path, reducing the transportation resistance.

[0047] In some embodiments, a feeding cover plate and a feeding valve may be arranged at the input end of the feeding chamber 111. The feeding cover plate can be opened and closed. When the feeding cover plate is opened, a feeding port can be formed, and the lithium battery electrode sheet to be processed is sent into the feeding chamber 111 through the feeding port. The feeding valve is used to control the feeding and stopping of the lithium battery electrode sheet.

[0048] In some embodiments, the feeding module 11 further includes a gas distribution system 115. The gas distribution system 115 includes an intake pipeline 114 and a gas distribution pipeline. A protective gas is introduced through the intake pipeline and transported to the gas distribution pipeline. The protective gas is evenly distributed in each area of the feeding chamber 111 through the gas distribution holes on the gas distribution pipeline, forming a stable oxygen-deficient environment. The lithium battery electrode sheet in the feeding chamber 111 is covered by the protective gas, which can ensure that the lithium iron phosphate cathode powder in the lithium battery electrode sheet does not oxidize. Exemplarily, the protective gas includes but is not limited to argon, nitrogen, helium, neon, krypton, etc. or a combination thereof.

[0049] In some embodiments, the gas distribution system has an automatic feedback function and can adjust the gas flow according to the feeding situation to maintain a stable internal gas concentration. Exemplarily, the gas distribution system includes a gas detector, which can be disposed in the feeding chamber 111 for real-time monitoring of the concentration of the protective gas during the feeding process, so that the gas distribution system can automatically adjust the gas distribution amount according to the detection result of the gas detector to ensure the stability of the oxygen-deficient environment in the feeding chamber 111. At the same time, the feeding speed of the lithium battery electrode is controlled by controlling the rotation speed of the spiral feeding rod 113 to avoid oxidation of the lithium battery electrode.

[0050] When applying the foregoing feeding module 11 to feed the lithium battery electrode, the feeding cover plate at the input end of the feeding chamber 111 is opened, and the lithium battery electrode is placed into the feeding chamber 111 and enters the feeding position through automatic or manual operation to ensure that the feeding amount per time is within the set range to maintain uniform and stable transportation; the feeding cover plate is closed to keep the feeding chamber 111 in a sealed state, and the feeding valve is moderately opened to control the feeding flow rate of the lithium battery electrode. These lithium battery electrodes are gradually introduced into the spiral feeding rod 113, and the spiral feeding rod 113 drives the lithium battery electrodes to gradually advance in the feeding chamber 111. During this process, the rotation speed of the spiral feeding rod 113 is controlled to ensure that the electrodes are not blocked or stacked; the feeding rod transports the electrodes to the feeding guide plate to prepare for the next step of guiding them into the pyrolysis and peeling module 13; at the same time, the gas distribution system 115 is started, and the protective gas is introduced through the intake pipe and transported to the gas distribution pipe, and is dispersed through each gas distribution hole on the gas distribution pipe. The protective gas slowly diffuses and covers the inside of the feeding chamber 111 to form a stable oxygen-deficient environment. Among them, the gas flow rate and distribution of the protective gas can be precisely adjusted through the regulating valve of the gas distribution system to ensure that the oxygen concentration in the cavity remains at a low level and avoid oxidation of the electrode material. The lithium battery electrode stably enters the feeding chamber, and the gas distribution system continues to operate to provide coverage of the protective gas for each batch of lithium battery electrodes entering, ensuring that the lithium iron phosphate cathode powder is not oxidized. Moreover, the feeding speed and the protective gas flow rate are coordinated to ensure that the gas fully covers the electrodes and there is no oxidation risk.

[0051] In some embodiments, the lithium battery lithium extraction device further includes an automatic loading system. The automatic loading system is disposed at the front end of the feeding chamber 111 in the feeding module 11. The automatic loading system can accurately send the lithium battery electrode into the feeding chamber 11 through intelligent control to ensure the uniformity and stability of the feeding amount of the lithium battery electrode, reduce manual intervention and improve the feeding efficiency.

[0052] The pyrolysis and peeling module 13 is used to perform pyrolysis treatment on the lithium battery electrode to peel off the lithium iron phosphate cathode powder and the aluminum current collector in the lithium battery electrode.

[0053] In some embodiments, the pyrolytic stripping module 13 may include a pyrolytic stripping chamber, a heating and auxiliary air system, and a flipping mechanism.

[0054] The pyrolytic stripping chamber 131 may be horizontally arranged, having an input end and an output end opposite to the input end. The input end is connected to the feeding chamber 111 of the feeding module, such that the pyrolytic stripping chamber 131 communicates with the feeding chamber 111. Exemplarily, the pyrolytic stripping chamber 131 is integrally cylindrical.

[0055] The heating and auxiliary air system cooperates with the flipping mechanism to strip the lithium iron phosphate cathode powder and aluminum current collector from the lithium battery electrode sheet. Among them, the heating and auxiliary air system is used to supply high-temperature hot air to the pyrolytic stripping chamber to decompose the binder in the lithium battery electrode sheet, and the flipping mechanism is used to flip the lithium battery electrode sheet in the stripping chamber.

[0056] As Figure 2 and 3 shown, the heating and auxiliary air system may be arranged between the pyrolytic stripping chamber and the feeding chamber of the feeding module. Please refer to Figure 4 and Figure 5 , among which, Figure 4 shows a front view of the heating and auxiliary air system in an embodiment, Figure 5 shows a side view of the heating and auxiliary air system in an embodiment.

[0057] In some embodiments, the heating and auxiliary air system 133 may include a heating housing 1331 and a heating plate 1332 and a hot air tank 1333 arranged in the heating housing 1331.

[0058] The heating housing 1331 may be horizontally arranged and integrally cylindrical.

[0059] The heating plate 1332 is arranged in the central area of the heating housing 1331, and is used to provide a high-temperature heat source and generate high-temperature hot air. In some embodiments, the heating plate 1332 is a plate-like structure, and the number of heating plates 1332 may be multiple. The multiple heating plates 1332 are arranged on a heating plate rotating groove 1330, and may be stacked on each other to form a circle, and a material conveying port 1334 is left in the center of the heating housing 1331. The lithium battery electrode sheet conveyed from the feeding mechanism of the feeding module 11 is conveyed into the pyrolytic stripping chamber 131 through the material conveying port 1334.

[0060] The hot air tank 1333 is arranged on the periphery of the heating plate 1332, and is used to introduce the high-temperature hot air generated by the heating plate 1332 into the pyrolytic stripping chamber 131 to pyrolyze the lithium battery electrode sheet. In some embodiments, as Figure 6As shown, the hot air duct 1333 is a pipe duct structure, and a hot air opening 1335 through which high-temperature hot air passes is provided inside. The number of hot air ducts 1333 is multiple, and the multiple hot air ducts 1333 are evenly arranged around the outside of the multiple heating plates 1332. Through the hot air openings 1335 in each hot air duct 1333, the high-temperature hot air generated by the multiple heating plates 1332 is continuously conveyed into the pyrolysis and stripping chamber.

[0061] In addition, the hot air duct 1333 is also internally provided with a wind valve 1336 and a wind guiding plate 1337. Through the wind valve 1336 and the wind guiding plate 1337, the inlet air flow rate of the high-temperature hot air flowing through the hot air opening 1335 can be controlled, so that the high-temperature hot air maintains a stable temperature and air flow, ensuring the efficiency of the stripping process. Exemplarily, by adjusting the opening degree of the wind valve 1336, the inlet air flow rate of the high-temperature hot air can be controlled. Exemplarily, by adjusting the position of the wind guiding plate 1337, the inlet air flow rate of the high-temperature hot air can be controlled. Exemplarily, by simultaneously adjusting the opening degree of the wind valve 1336 and the position of the wind guiding plate 1337, the inlet air flow rate of the high-temperature hot air can be controlled. Of course, by controlling the inlet air flow rate of the high-temperature hot air, the temperature of the high-temperature hot air can also be changed to a certain extent.

[0062] Using the heating and auxiliary air system, sufficient high-temperature hot air can be provided for the pyrolysis and stripping chamber 131, so that the lithium battery electrode sheet in the pyrolysis and stripping chamber 131 is pyrolyzed, that is, the binder between the lithium iron phosphate cathode powder and the aluminum current collector in the lithium battery electrode sheet is decomposed, thereby stripping the lithium iron phosphate cathode powder.

[0063] In practical applications, the heating plates 1332 in the heating and auxiliary air system are gradually heated up to provide a stable and uniform high-temperature heat source. The high-temperature hot air is introduced into the pyrolysis and stripping chamber 131 through the hot air duct 1333 to ensure uniform temperature distribution. After the lithium battery electrode sheet enters the pyrolysis and stripping chamber 131, it is transported at a set feeding speed. During the transportation process, under the action of high temperature, the binder on the lithium battery electrode sheet is gradually decomposed, so that the lithium iron phosphate cathode powder and the aluminum current collector are effectively separated. During this process, the wind valve 1336 and the wind guiding plate 1337 cooperate to adjust the air flow in the pyrolysis and stripping chamber 131, so that the hot air circulates in the pyrolysis and stripping chamber 131, avoiding local overheating or uneven temperature. Through the uniform distribution of the air flow, all areas on the lithium battery electrode sheet can be fully heated, accelerating the decomposition of the binder and improving the stripping efficiency of the lithium iron phosphate cathode powder. After the air flow is stable, the stripped lithium iron phosphate cathode powder gradually gathers below in the pyrolysis and stripping chamber 131, preparing for subsequent transportation and sorting. During the whole process, the heating and auxiliary air system 133, the wind valve 1336 and the wind guiding plate 1337 cooperate closely to ensure precise control of the temperature and air flow, making the stripping process efficient and stable.

[0064] The binder between the lithium iron phosphate cathode powder and the aluminum current collector can be, for example, polyvinylidene fluoride PVDF. Please refer to Figure 7, which shows a schematic diagram of thermo-gravimetry analysis (TGA) and differential thermal analysis (DTA) using polyvinylidene fluoride (PVDF) as a binder.

[0065] By pyrolyzing the binder to strip the lithium iron phosphate cathode powder, the advantage is to make full use of the high thermal conduction speed of high-temperature hot air to melt the binder (PVDF) between the positive aluminum current collector and the cathode material, and at the same time, sweep and collect the lithium iron phosphate cathode powder through high-temperature hot air blowing to achieve the effect of removing the binder and stripping the powder. To achieve the effect of melting the binder and not damaging the crystal structure of lithium iron phosphate, it is necessary to control the temperature and inlet air flow rate of the high-temperature hot air to reach the decomposition temperature of the binder and sufficient residence time.

[0066] As Figure 7 shown, the corresponding weight change curve with temperature is obtained through TGA, and the corresponding heat change curve with temperature is obtained through DTA. It can be seen that in the TGA weight change curve with temperature, an obvious weight loss peak appears when the temperature is between 450°C and 650°C; in the DTA heat change curve with temperature, an obvious conversion from exothermic to endothermic peak appears when the temperature is between 450°C and 650°C, fully proving that the binder decomposes in this temperature range, and until an obvious and sharp endothermic peak appears at about 700°C, it means that the crystal of lithium iron phosphate is damaged.

[0067] Therefore, in the temperature range of 450°C to 650°C, the effect of melting the binder and not damaging the crystal structure of lithium iron phosphate can be achieved. Therefore, the temperature range of the high-temperature hot air can be controlled between 450°C and 650°C.

[0068] In addition, to control the temperature of the high-temperature hot air and match the corresponding inlet air flow rate, the corresponding relationship between the inlet air flow rate (cubic meters per second or m 3 / s) and temperature (degrees Celsius or °C) of the high-temperature hot air is set under different feeding flow rates (kilograms per minute or kg / m) of the lithium battery electrode sheets.

[0069] In some embodiments, when the feeding flow rate is from 0.5 kg / min to 1 kg / min, the inlet air flow rate is (T - 450) / 450 + 1 m / s, where T is the temperature of the high-temperature hot air.

[0070] In some embodiments, when the feeding flow rate is from 1 kg / min to 10 kg / min, the inlet air flow rate is (T - 450) / 450 + 1.5 m / s, where T is the temperature of the high-temperature hot air.

[0071] In some embodiments, when the feed flow rate is from 10 kg / min to 30 kg / min, the inlet air flow rate is (T - 450) / 450 + 2 m³ / s, where T is the temperature of the high-temperature hot air.

[0072] Please refer to Figure 8 and Figure 9 , where Figure 8 shows the front view of the flipping mechanism in one embodiment, Figure 9 shows the side view of the flipping mechanism in one embodiment.

[0073] As shown in the figure, the flipping mechanism is disposed in the pyrolysis and stripping chamber 131. The flipping mechanism includes a drum 135, a drum driving unit, and a drum feeding chute 137. The drum 135 can be horizontally arranged, having an input end and an output end opposite to the input end. The input end can be provided with a drum feeding guide plate 1351. In some embodiments, the heating and auxiliary air system can cooperate with the drum feeding guide plate 1351. The drum feeding guide plate 1351 is provided with an auxiliary air feeding port, and the heating and auxiliary air system is embedded in the auxiliary air feeding port and then connected to the pyrolysis and stripping chamber 131. Exemplarily, the drum 135 is integrally in a cylindrical shape.

[0074] The drum driving unit is used to drive the drum 135 to flip. In some embodiments, the drum driving unit may further include: a drum driving motor, a drum chain gear 1352, and a drum roller 1353. Among them, the drum driving motor is used to provide driving force. The drum chain gear 1352 is disposed on the outer peripheral surface of the drum 135. The drum roller 1353 is rotatably arranged and is provided with a driving gear. The driving gear of the drum roller 1353 is correspondingly meshed with the drum chain gear 1352, and the drum roller 1353 is controlled by the drum driving motor. For the convenience of the arrangement of the drum roller 1353 and the closer cooperation between the drum roller 1353 and the drum chain gear 1352, in some alternative embodiments, the drum driving unit may further include a drum chute 1354. The drum chute 1354 is disposed on the outer peripheral surface of the drum 135 and corresponds to the drum roller 1353. The drum chain gear 1352 is adjacent to the edge of the drum chute. The drum roller 1353 correspondingly fits on the drum chute 1354. Thus, by driving the drum roller 1353 to rotate through the drum driving motor, the rotating drum roller 1353 drives the drum 135 to flip through the engaged drum chain gear 1352, so that the lithium battery electrode sheets (including the lithium iron phosphate cathode powder and aluminum current collector that have been stripped out) in the drum 135 roll over, and the lithium iron phosphate cathode powder is effectively stripped from the aluminum current collector. Among them, the drum driving motor can achieve forward and reverse rotation. Therefore, the drum 135 can rotate forward, reverse, or rotate forward and reverse alternately under the control of the drum driving motor.

[0075] In some alternative embodiments, components such as the drum drive motor, drum chain teeth 1352, drum chute 1354, and drum roller 1353 in the drum drive unit may be multiple. For example, some of the drum drive motors, drum chain teeth 1352, drum chute 1354, and drum roller 1353 are arranged at the input end of the drum 135, and some of the drum drive motors, drum chain teeth 1352, drum chute 1354, and drum roller 1353 are arranged at the output end of the drum 135, thereby ensuring the smoothness of the drum 135 during flipping.

[0076] The drum guide chute 137 is arranged inside the drum 135 and is used to support the lithium battery electrode sheet and convey and transfer the lithium iron phosphate cathode powder and aluminum current collector that are peeled off. In some embodiments, the drum guide chute 137 adopts a spiral structure. During the process of the drum guide chute 137 flipping along with the drum 135, it drives the lithium battery electrode sheet, the peeled lithium iron phosphate cathode powder, and the aluminum current collector to gradually advance from the input end of the drum 135 towards the output end of the drum 135, and during the flipping process, it is continuously affected by high-temperature pyrolysis and air flow, accelerating the decomposition of the binder.

[0077] Similarly, protective gas is evenly distributed in each area inside the drum 135 through the aforementioned gas distribution system 115 to form a stable oxygen-deficient environment. The lithium battery electrode sheet is covered by the protective gas and undergoes pyrolysis and flipping in the oxygen-deficient environment, which can ensure that the lithium iron phosphate cathode powder in the lithium battery electrode sheet does not oxidize. Exemplarily, the protective gas includes but is not limited to argon, nitrogen, helium, neon, krypton, etc. or a combination thereof. Of course, it can also be achieved by using an independent gas distribution system.

[0078] Therefore, in the pyrolysis and peeling module, the drum in the pyrolysis and peeling chamber is in an oxygen-deficient environment covered by protective gas. On the one hand, through the heating and auxiliary air system, the pyrolysis and peeling chamber is filled with high-temperature hot air to pyrolyze the lithium battery electrode sheet, that is, to decompose the binder between the lithium iron phosphate cathode powder and the aluminum current collector in the lithium battery electrode sheet, thereby peeling off the lithium iron phosphate cathode powder from the lithium battery electrode sheet; on the other hand, during the pyrolysis of the lithium battery electrode sheet, the lithium battery electrode sheet is flipped through the flipping mechanism, which not only enables each part of the lithium battery electrode sheet to undergo pyrolysis under the action of high-temperature hot air, but also makes it more conducive to the effective peeling of the lithium iron phosphate cathode powder from the aluminum current collector during the flipping of the lithium battery. The entire flipping process ensures that each side of the lithium battery electrode sheet can be fully heated by controlling the rotation speed of the drum 135, the inclination angle of the drum guide chute 137, and the air flow intensity, and completes the peeling under appropriate pressure and angle. Under the dual action of rotation and air flow, the peeled lithium iron phosphate cathode powder gradually settles to the bottom of the drum 135 and gradually moves towards the output end of the drum 135, greatly improving the peeling effect and peeling efficiency.

[0079] At the output end of the roller 135, there is a discharging head 1355. During the flipping process of the roller 135, the lithium battery electrode sheet, the stripped lithium iron phosphate cathode powder, and the aluminum current collector are gradually pushed from the input end of the roller 135 towards the output end of the roller 135 through the roller material guiding chute 137, and the stripped lithium iron phosphate cathode powder and the aluminum current collector are output through the discharging hopper 1355. Among them, during the process of gradually pushing the lithium battery electrode sheet, the stripped lithium iron phosphate cathode powder, and the aluminum current collector from the input end of the roller 135 towards the output end of the roller 135 through the roller material guiding chute 137, in the first half of the roller material guiding chute 137, it is mainly the lithium battery electrode sheet. As the lithium battery electrode sheet gradually strips out the lithium iron phosphate cathode powder and the aluminum current collector during the continuous pyrolysis process, in the second half of the roller material guiding chute 137, it is basically the stripped lithium iron phosphate cathode powder and the aluminum current collector. Until finally, the stripped lithium iron phosphate cathode powder and the aluminum current collector are discharged from the discharging hopper 1355.

[0080] In addition, in the flipping mechanism, a material guiding baffle 1356 can also be included. The material guiding baffle 1356 can be arranged at the output end of the roller 135 and adjacent to the discharging hopper 1355, and is used to block and limit the materials (such as lithium battery electrode sheets, stripped lithium iron phosphate cathode powder, and aluminum current collectors) for flipping the roller 135. As described above, in the second half of the roller material guiding chute 137, it is mainly the lithium iron phosphate cathode powder and the aluminum current collector stripped by pyrolysis. Generally, the particles of the lithium iron phosphate cathode powder are smaller than those of the aluminum current collector, and the weight of the lithium iron phosphate cathode powder is lighter than that of the aluminum current collector. If flipped by the roller 135, the lithium iron phosphate cathode powder will fly during the flipping process, which is not conducive to subsequent collection and discharging through the discharging hopper 1355. Therefore, by setting the material guiding baffle 1356, it can play a certain limiting role on the materials, especially for the lithium iron phosphate cathode powder, restricting its flipping range of motion and reducing its flying degree, which is more conducive to subsequent collection and discharging. In some embodiments, the material guiding baffle 1356 has a certain length and is set at a relatively low height. For example, it is lower than the middle boundary line of the roller (i.e., located within the lower half circle of the roller). Of course, the structure and setting position of the material guiding baffle 1356 can still have other variations, which are not limited here.

[0081] In addition, in some embodiments, the pyrolysis stripping module 13 is also provided with a temperature detector for real-time detecting the temperature in the pyrolysis stripping chamber 131 and controlling the heating temperature of the heating plate 1332 according to the detected temperature.

[0082] In some embodiments, the pyrolysis stripping module 13 is also provided with a humidity detector for real-time detecting the humidity in the pyrolysis stripping chamber 131 to prevent abnormal humidity from affecting the physical properties of the lithium iron phosphate cathode powder.

[0083] In some embodiments, the pyrolysis stripping module 13 is further provided with a flame monitor for real-time monitoring of the flame or abnormal temperature conditions during high-temperature operations to ensure the safety of the equipment.

[0084] The cooling and preliminary separation module 15 is used to cool and preliminarily separate the mixed material of the lithium iron phosphate cathode powder and the aluminum current collector stripped out, to obtain the material containing the lithium iron phosphate cathode powder.

[0085] In some embodiments, the cooling and preliminary separation module 14 includes: a cooling chamber 151, a material blowing assembly, a suction hopper 153, and a main air duct 155.

[0086] The cooling chamber 151 is arranged below the pyrolysis stripping module 13, and the stripped lithium iron phosphate cathode powder and aluminum current collector discharged from the discharge hopper 1355 of the drum 135 in the pyrolysis stripping module 13 are transported into the lower cooling chamber 151.

[0087] In some embodiments, a cooling assembly is configured in the cooling chamber 151. By using the cooling assembly, it can be ensured that the cooling chamber 151 is in a low-temperature environment, and the mixed material of the lithium iron phosphate cathode powder and the aluminum current collector can be cooled. In some alternative embodiments, the cooling assembly may include an air-cooling assembly. Through the air-cooling assembly, low-temperature air flow with a lower temperature is input into the cooling chamber 151. The low-temperature air flow fills each area of the cooling chamber 151 to adsorb heat to achieve cooling, and then the gas adsorbed with heat is sent out from the cooling chamber 151. Through the heat exchange of the low-temperature air flow, it can be ensured that the cooling chamber 151 is maintained in the required low-temperature environment. In the low-temperature environment, the physical properties of the lithium iron phosphate cathode powder and the aluminum current collector can change. The physical properties of the lithium iron phosphate cathode powder and the aluminum current collector are different. Therefore, after the physical properties of the lithium iron phosphate cathode powder and the aluminum current collector change respectively, it is more convenient to separate them.

[0088] The material blowing assembly is used to blow off the lithium iron phosphate cathode powder from the mixed material including the stripped lithium iron phosphate cathode powder and aluminum current collector.

[0089] In some embodiments, the material blowing assembly may include a heat-resistant conveyor belt 152 and a blower equipped with a blowing port 154.

[0090] The heat-resistant conveyor belt 152 is used to transport the mixed material of the lithium iron phosphate cathode powder and the aluminum current collector.

[0091] The blower provides the corresponding air flow and outputs it through the blowing port 154.

[0092] As described above, the particles of the lithium iron phosphate cathode powder are relatively small compared to the aluminum current collector, and the weight of the lithium iron phosphate cathode powder is relatively light compared to the aluminum current collector. Therefore, as shown in the figure, the hair dryer can be arranged below the heat-resistant conveyor belt 152, and the air outlet 154 of the hair dryer is arranged upward. Correspondingly, the suction hopper 153 is arranged above the heat-resistant conveyor belt 152 and its opening faces the heat-resistant conveyor belt 152 directly. In this way, the air flow provided by the hair dryer is output upward through the air outlet 154, and the lithium iron phosphate cathode powder placed on the heat-resistant conveyor belt 152 is lifted upward by the air flow and absorbed by the upper suction hopper 153. Here, in fact, the air flow provided by the hair dryer can also play a role in peeling off the lithium iron phosphate cathode powder that was not peeled off before but still adhered to the aluminum current collector. That is, the lithium iron phosphate cathode powder that is blown up and absorbed by the suction hopper includes not only the previously peeled lithium iron phosphate cathode powder but also a part of the lithium iron phosphate cathode powder that is blown off from the aluminum current collector under the action of the air flow.

[0093] As can be seen from the above, most of the materials blown up by the air flow provided by the hair dryer are lithium iron phosphate cathode powder, and there may also be some aluminum current collector mixed in. Therefore, these materials mainly composed of lithium iron phosphate cathode powder that may be mixed with aluminum current collector can be called materials containing lithium iron phosphate cathode powder.

[0094] The suction hopper 153 is communicated with the main air duct 155. The suction hopper 153 is used to collect the materials containing lithium iron phosphate cathode powder and transport them to the separation and collection module 17 through the main air duct 155 for further processing.

[0095] In some embodiments, the cooling and preliminary separation module 15 is configured with a negative pressure assisted separation system. The negative pressure assisted separation system forms a negative pressure in the suction hopper 153 and the main air duct 155 to assist in separating the fine lithium iron phosphate cathode powder from the aluminum current collector and improve the operation efficiency of separation and collection.

[0096] In addition, in some embodiments, there is also a discharge port 156. By using the discharge port 156, the remaining aluminum current collector can be discharged. Subsequently, the aluminum current collector can be further processed by corresponding components for recycling. Exemplarily, the aluminum current collector can be separated into aluminum materials through a vibrating screen.

[0097] In some embodiments, the cooling and preliminary separation module 15 can be configured with a conveyor belt at the discharge port 156. The conveyor belt is used to transport the aluminum current collector discharged from the discharge port 156 to the corresponding storage bin to ensure the continuous transmission and automatic collection of materials.

[0098] The separation and collection module 17 is used to separate the materials containing lithium iron phosphate cathode powder obtained in the cooling and preliminary separation module 15 and collect the separated lithium iron phosphate cathode powder.

[0099] In some embodiments, the separation and collection module includes: an analyzer 171 and a straight-line sieve 173.

[0100] The analyzer 171 is used to separate the material containing lithium iron phosphate cathode powder.

[0101] After the material is transported to the analyzer 171 through the main air duct 155, the analyzer 171 uses double-vortex motion to separate the air flow. Among them, the heavier aluminum current collector in the material is affected by the centrifugal force and moves outward and settles, while the lighter lithium iron phosphate cathode powder in the material remains in the air flow and further moves to the straight-line sieve 173.

[0102] In addition, to ensure the safety of the equipment, the main air duct 155 is equipped with a pressure detector and a relief valve for the main air duct. The pressure detector is used to detect the gas pressure in the main air duct 155 in real time, and the relief valve 1551 for the main air duct automatically relieves pressure when the pressure detector detects that the air flow pressure in the main air duct 155 is higher than the set threshold, protecting the stable operation of the equipment.

[0103] The straight-line sieve 173 is arranged below the analyzer 171 and is connected to the analyzer 171, and is used for further separation according to the particle size of the material.

[0104] In some optional embodiments, the straight-line sieve 173 includes a primary screen. Through the primary screen, the material containing lithium iron phosphate cathode powder separated by the analyzer 171 can be screened, the relatively larger aluminum current collector particles can be screened out, and the screened aluminum current collector can be discharged through the aluminum discharge port, and the remaining is the lithium iron phosphate cathode powder.

[0105] In some optional embodiments, the straight-line sieve 173 includes a primary screen and a secondary screen, where the mesh number of the secondary screen is larger than that of the primary screen. Through the primary screen, the material containing lithium iron phosphate cathode powder separated by the analyzer 171 can be screened, the relatively larger aluminum current collector particles can be screened out and discharged, and the remaining material is then screened by the secondary screen. Through the secondary screen, the first-particle lithium iron phosphate cathode powder and the second-particle lithium iron phosphate cathode powder with a smaller particle size than the first particle can be screened out. By setting a screen or multiple screens with different pore sizes, the straight-line sieve 173 can classify and screen the aluminum current collector and the lithium iron phosphate cathode powder, separate particles of different sizes and export them, realizing the precise classification and effective separation of the material.

[0106] The ultrasonic piezoelectric lithium extraction module 19 is used to generate piezoelectric effect through ultrasonic waves, generate micro-vibrations and act on the lithium iron phosphate cathode powder to dissociate lithium ions therefrom.

[0107] In some embodiments, the ultrasonic piezoelectric lithium extraction module 19 includes: an ultrasonic piezoelectric reaction chamber 191, a liquid injector 192, an ultrasonic generator 193, an ultrasonic transducer 194, and a piezoelectric generator 195.

[0108] The ultrasonic piezoelectric reaction chamber 191 is disposed below the separation and collection module 17. Exemplarily, the ultrasonic piezoelectric reaction chamber 191 is generally cylindrical in shape.

[0109] The liquid injector 192 injects liquid into the ultrasonic piezoelectric reaction chamber 191 through a water injection port. Exemplarily, the liquid is water.

[0110] In addition, a liquid level detector may be disposed inside the ultrasonic piezoelectric reaction chamber 191 to detect in real time the liquid level in the ultrasonic piezoelectric reaction chamber 191 using the liquid level detector, and when the detected liquid level is lower than a preset liquid level threshold or liquid level threshold range, trigger the liquid injector 192 to cause the liquid injector 192 to inject liquid into the ultrasonic piezoelectric reaction chamber 191 until the liquid level meets the requirements of the liquid level threshold or liquid level threshold range to ensure that the liquid level always remains at the optimal level and ensure that the synergistic effect of ultrasonic waves and piezoelectric effect in the liquid phase environment reaches the best effect.

[0111] The piezoelectric generator 195 is disposed inside the ultrasonic piezoelectric reaction chamber 191 and is used to generate a piezoelectric effect after being controlled. In some alternative embodiments, the piezoelectric generator 195 may, for example, adopt a piezoelectric bead chain network, and the piezoelectric bead chain network adopts a surface piezoelectric coating or an integrally die-cast structure form. In some alternative embodiments, the piezoelectric coating includes, but is not limited to, one or more of bismuth ferrite, polytetrafluoroethylene (PTFE), quartz, barium titanate, lead zirconate titanate (PZT), polyvinylidene fluoride (PVDF), polymer piezoelectric film, lithium niobate, lead zirconate, perovskite material, sodium polyacrylate, polylactic acid (PLA). The coating can be attached to the surface of the beads by methods such as magnetron sputtering, precipitation, brushing, thermoplastic or gluing to ensure its durability and stability under high-frequency vibration conditions. To prevent the coating from peeling off during long-term use, the piezoelectric bead chain network can also be directly die-cast using one or more of the above materials. It can be seen that the piezoelectric bead chain network adopts a highly durable coating, combined by various methods such as magnetron sputtering and brushing, which greatly improves the anti-wear performance and the service life of the piezoelectric component. However, the piezoelectric generator 195 is not limited to adopting a piezoelectric bead chain network. In other embodiments, the piezoelectric generator 195 may also adopt, but is not limited to, a bead chain, a particle-embedded network, a grid-shaped piezoelectric sheet, or a sheet-like distributed piezoelectric film to adapt to different vibration requirements and hydrodynamic environments.

[0112] By injecting liquid into the ultrasonic piezoelectric reaction chamber 191 through the liquid injector 192, the piezoelectric generator 195 can be partially or completely immersed in the liquid.

[0113] The ultrasonic generator 193 transmits ultrasonic waves to the piezoelectric generator 195 (e.g., a piezoelectric bead chain network) through the ultrasonic transducer 194, exciting the piezoelectric generator 195 to generate the piezoelectric effect, and using the piezoelectric effect to cause the lithium iron phosphate cathode powder to release lithium ions in the liquid phase. Among them, the design of the piezoelectric bead chain network enables the piezoelectric effect to act uniformly on the lithium iron phosphate cathode powder, significantly improving the dissociation efficiency of lithium ions.

[0114] In practical applications, the lithium iron phosphate cathode powder separated and collected by the separation and collection module 17 is sent into the ultrasonic piezoelectric reaction chamber 191, and an appropriate amount of liquid (e.g., water) is injected into the ultrasonic piezoelectric reaction chamber 191 by the injector 192 until the liquid level in the ultrasonic piezoelectric reaction chamber 191 reaches a preset liquid level threshold or liquid level threshold range. At this time, the ultrasonic generator 193 transmits ultrasonic waves to the piezoelectric generator 195 (e.g., a piezoelectric bead chain network) through the ultrasonic transducer 194, exciting the piezoelectric generator 195 to generate the piezoelectric effect, directly acting on the lithium iron phosphate cathode powder in the liquid phase, triggering the release of lithium ions, gradually dissociating and dissolving to form a lithium solution, while the reacted lithium iron phosphate cathode powder is converted into lithium-free lithium iron phosphate.

[0115] Using ultrasonic piezoelectric technology, lithium ions can be extracted from the lithium iron phosphate cathode powder in the liquid phase. Lithium iron phosphate is susceptible to oxidation. The divalent iron in lithium iron phosphate is oxidized to trivalent iron, and the lithium ions are occupied by iron at the position of lithium iron phosphate, so that the lithium ions are extruded from the lithium iron phosphate olivine crystal and dissolved into the water body. Subsequently, through simple solid-liquid separation, lithium-free lithium iron phosphate slag and lithium-rich solution can be obtained. The piezoelectric lithium extraction reaction mainly has three functions. One is that the solid-liquid phase friction piezoelectricity between the piezoelectric material and water enables the surface charge of the piezoelectric material to transfer to the surface of water molecules and easily generates hydroxyl radicals. Hydroxyl radicals have high oxidation activity and can oxidize lithium iron phosphate. The second is that the solid-solid phase friction piezoelectricity between the piezoelectric materials and between the piezoelectric materials and lithium iron phosphate enables the electrons in lithium iron phosphate to directly transfer to the surface of the piezoelectric material. Under the action of the microelectric field force on the surface of the piezoelectric material, the lithium ions migrate out of the intrinsic solid phase and dissolve in the water body. The third is that the solid-gas phase friction piezoelectricity between the piezoelectric material and the oxygen molecules in the water enables the surface charge of the piezoelectric material to transfer to the surface of the oxygen molecules to generate superoxide radicals, oxidize lithium iron phosphate, and release lithium ions into the water.

[0116] The most important reaction of piezoelectricity is to generate highly active oxidizing components (hydroxyl radicals, superoxide radicals, hydrogen peroxide, etc.). This piezoelectric reaction is in-situ generated by the piezoelectric material and water. Except for water and the piezoelectric material, no additional chemical substances are added, and the reaction does not require the participation of additional mechanical force, having the advantages of being green, pollution-free, and economical.

[0117] The lithium battery lithium extraction device of the present disclosure may further include a lithium solution screening module located at the rear end of the ultrasonic piezoelectric lithium extraction module.

[0118] The lithium liquid screening module is used to screen the lithium liquid in the ultrasonic piezoelectric lithium extraction module 19.

[0119] In some embodiments, the lithium liquid screening module may include a pole powder screening chamber 181, a lithium liquid collecting hopper 183, a pole powder sieve plate 185, and a lithium liquid discharge port 187.

[0120] The pole powder screening chamber 181 is arranged below the ultrasonic piezoelectric reaction chamber 191, or the pole powder screening chamber 181 is arranged beside and below the ultrasonic piezoelectric reaction chamber 191. Exemplarily, the overall shape of the pole powder screening chamber 181 is cylindrical.

[0121] The lithium liquid collecting hopper 183 is arranged at the bottom of the pole powder screening chamber 181. The lithium liquid collecting hopper 183 is communicated with the pole powder screening chamber 181, and a lithium liquid discharge port 187 is arranged at the bottom of the lithium liquid collecting hopper 183. In some alternative embodiments, the pole powder screening chamber 181 and the lithium liquid collecting hopper 183 are two independent components and are combined together during use. In some alternative embodiments, the pole powder screening chamber 181 and the lithium liquid collecting hopper 183 are integrally formed.

[0122] The pole powder sieve plate 185 is arranged inside the pole powder screening chamber 181 and above the lithium liquid collecting hopper 183, and is used to screen the lithium liquid released from the ultrasonic piezoelectric reaction chamber 191 of the ultrasonic piezoelectric lithium extraction module 19 to screen out the lithium-free iron phosphate particles in the lithium liquid. The lithium liquid from which the lithium-free iron phosphate particles have been screened out flows through the pole powder sieve plate 185 into the lithium liquid collecting hopper 183 and is output through the lithium liquid discharge port 187 at the bottom. Exemplarily, the pole powder sieve plate 185 may be inclined. Exemplarily, the pole powder sieve plate 185 may be horizontally arranged.

[0123] In some embodiments, a sieve chamber gate 189 is further arranged near the pole powder sieve plate 185 in the pole powder screening chamber 181. Through the sieve chamber gate 189, the lithium-free iron phosphate particles remaining on the pole powder sieve plate 185 can be taken out.

[0124] Thus, in the lithium extraction device for lithium batteries of the present disclosure, through the coordinated cooperation among the various modules, the lithium iron phosphate cathode powder can be peeled off by pyrolysis, and lithium ions can be dissociated from the lithium iron phosphate cathode powder by combining with the ultrasonic piezoelectric method.

[0125] In addition, it should be noted that there may be other setting changes in the lithium extraction device for lithium batteries of the present disclosure.

[0126] In some embodiments, the lithium extraction device for lithium batteries may be configured with a quality monitor in one module or some modules, and the flow condition of the material is tracked through the quality monitor to ensure smooth material flow in each module.

[0127] In some embodiments, the lithium extraction device for lithium batteries is configured with an automatic cleaning module to clean the components within the corresponding module. High-pressure water or cleaning gas is used to ensure that each module is clean and unobstructed, thereby extending the service life of the equipment. Exemplarily, the automatic cleaning module can be arranged, for example, within the pyrolysis stripping module to regularly clean the drum within the pyrolysis stripping module. Or, exemplarily, the automatic cleaning module can be arranged, for example, within the separation and collection module to regularly clean the linear screen within the separation and collection module. Exemplarily, the automatic cleaning module can be arranged, for example, within the ultrasonic piezoelectric lithium extraction module to regularly clean the ultrasonic piezoelectric reaction chamber within the ultrasonic piezoelectric lithium extraction module.

[0128] In some embodiments, the lithium extraction device for lithium batteries is configured with an overload protection module. The overload protection module monitors the working loads of key components in real time. If overload or abnormal pressure conditions are detected, it will automatically decelerate or stop the equipment and issue an alarm to protect the device and the materials from damage.

[0129] The lithium extraction device for lithium batteries provided by the embodiments of the present disclosure includes: a feeding module, a pyrolysis stripping module, a separation and collection module, and an ultrasonic piezoelectric lithium extraction module. The feeding module is used to convey the lithium battery electrode sheets to be processed to the pyrolysis stripping module. The pyrolysis stripping module pyrolyzes the lithium battery electrode sheets through the coordinated cooperation of a heating and auxiliary air system and a flipping mechanism to strip out the lithium iron phosphate cathode powder. The separation and collection module separates the lithium iron phosphate cathode powder and the aluminum current collector stripped out in the pyrolysis stripping module and collects the lithium iron phosphate cathode powder. The ultrasonic piezoelectric lithium extraction module generates micro-vibrations through the piezoelectric effect induced by ultrasonic waves and acts on the lithium iron phosphate cathode powder to dissociate lithium ions therefrom. The present disclosure can strip out the lithium iron phosphate cathode powder through pyrolysis and combine the ultrasonic piezoelectric method to dissociate lithium ions from the lithium iron phosphate cathode powder. Compared with the related technologies using mechanical crushing methods or chemical leaching methods, it has the advantages of rapid and thorough stripping of the lithium iron phosphate cathode powder, energy conservation and environmental protection, good lithium extraction effect and high lithium extraction efficiency, low operating cost, and suitability for large-scale applications.

[0130] The embodiments of the present disclosure provide a lithium extraction method for lithium batteries, which is applied to the lithium extraction device as described above.

[0131] Please refer to Figure 10 , which shows the schematic flow diagram of the lithium extraction method for lithium batteries in an embodiment.

[0132] Combined with Figure 1 and Figure 10 , the lithium extraction method for lithium batteries may include the following steps: Step S201, use the feeding module to send the lithium battery electrode sheets to be processed into the pyrolysis stripping module.

[0133] Step S203: Use the pyrolysis peeling module to provide high-temperature hot air through heating and the auxiliary air supply system to pyrolyze the lithium battery electrode sheet to peel off the lithium iron phosphate cathode powder, and use the flipping mechanism to flip the lithium battery electrode sheet during the pyrolysis process to accelerate the peeling of the lithium iron phosphate cathode powder.

[0134] Step S205: Use the cooling and preliminary separation module to cool and preliminarily separate the mixed material of the peeled lithium iron phosphate cathode powder and the aluminum current collector to obtain the material containing the lithium iron phosphate cathode powder. Step 207: Use the separation and collection module to separate the material containing the lithium iron phosphate cathode powder and collect the separated lithium iron phosphate cathode powder.

[0135] Step S209: Use the ultrasonic piezoelectric lithium extraction module to trigger the piezoelectric effect through ultrasonic waves, generate micro-vibrations and act on the lithium iron phosphate cathode powder to dissociate lithium ions therefrom.

[0136] The following details the entire process of applying the lithium extraction method for lithium batteries of the present disclosure to a lithium battery lithium extraction device.

[0137] After the lithium battery lithium extraction device is started, each module starts to operate.

[0138] First, the lithium battery electrode sheet is evenly and continuously fed into the feed chamber of the feed module through the automatic loading system. In the feed chamber, the protective gas is delivered to the inside of the feed chamber and the inside of the pyrolysis peeling chamber through the intake pipe and the air distribution pipe of the air distribution system, so as to form a stable oxygen-deficient environment inside the feed chamber and the inside of the pyrolysis peeling chamber. The lithium battery electrode sheet is gradually introduced into the spiral feed rod, and the spiral feed rod drives the lithium battery electrode sheet to advance step by step in the feed chamber. During this process, the rotation speed of the spiral feed rod is controlled to ensure that the electrode sheet is not blocked or piled up, and the lithium battery electrode sheet is gradually fed into the pyrolysis peeling chamber of the pyrolysis peeling module.

[0139] The lithium battery electrode sheet is fed into the pyrolysis peeling chamber of the pyrolysis peeling module, and the heating and auxiliary air supply system is automatically activated. The heating plate is gradually heated to provide a high-temperature heat source and generate high-temperature hot air. The high-temperature hot air is introduced into the pyrolysis peeling chamber through the hot air groove to uniformly heat the lithium battery electrode sheet to ensure that the binder is fully decomposed and the lithium iron phosphate cathode powder is preliminarily peeled off from the aluminum current collector. At the same time, the driving roller rotates to drive the lithium battery electrode sheet to flip, so that the lithium iron phosphate cathode powder is peeled off from the aluminum current collector.

[0140] The separated lithium iron phosphate cathode powder and aluminum current collector are transported to the cooling chamber of the cooling and preliminary separation module for cooling, and the cooled material containing the lithium iron phosphate cathode powder is absorbed into the main air duct through the suction hopper.

[0141] The material containing lithium iron phosphate cathode powder is transported to the separation and collection module through the main air duct. The heavier aluminum current collector is automatically separated by the double-vortex motion of the analyzer, and the lighter lithium iron phosphate cathode powder is introduced into the linear sieve for particle size screening.

[0142] The separated lithium iron phosphate cathode powder is automatically transferred to the ultrasonic piezoelectric reaction chamber. The injector 192 injects liquid into the ultrasonic piezoelectric reaction chamber. When the liquid level reaches the standard, the ultrasonic generator transmits ultrasonic waves to the piezoelectric generator (for example, a piezoelectric bead chain net) through the ultrasonic transducer, exciting the piezoelectric generator to generate the piezoelectric effect. To utilize the piezoelectric effect, the lithium iron phosphate cathode powder releases lithium ions in the liquid phase, and the extracted lithium ions dissolve in the liquid to form lithium solution.

[0143] Subsequently, the lithium solution is sent to the cathode powder screening chamber of the lithium solution screening module, and impurities (such as lithium-free iron phosphate particles) in the lithium solution are screened out through the cathode powder sieve plate to obtain a lithium solution meeting the production requirements.

[0144] The above embodiments merely illustrate the principles and effects of the present disclosure, rather than limiting the present disclosure. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present disclosure. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present disclosure should still be covered by the protection scope of the present disclosure.

Claims

1. A lithium battery lithium extraction device, characterized in that: include: A feeding module, comprising a feeding chamber and a feeding mechanism, through which the lithium battery pole pieces to be processed are fed into the feeding chamber; A pyrolysis stripping module, comprising a pyrolysis stripping chamber, a heating and auxiliary air system, and a flipping mechanism, wherein the pyrolysis stripping chamber is connected to the feed chamber, and the heating and auxiliary air system cooperates with the flipping mechanism to strip the lithium iron phosphate positive electrode powder and the aluminum current collector in the lithium battery pole piece, wherein the heating and auxiliary air system is used to provide high-temperature hot air to the pyrolysis stripping chamber to decompose the binder in the lithium battery pole piece, and the flipping mechanism is used to flip the lithium battery pole piece in the stripping chamber; A cooling and initial separation module, used to cool and initially separate the stripped mixture of lithium iron phosphate positive electrode powder and aluminum current collector to obtain a material containing lithium iron phosphate positive electrode powder; A separation and collection module, used for separating the material containing lithium iron phosphate positive electrode powder obtained in the cooling and primary separation module and collecting the separated lithium iron phosphate positive electrode powder; and The ultrasonic piezoelectric lithium extraction module is used to induce the piezoelectric effect through ultrasonic waves, generate micro-vibrations and act on the lithium iron phosphate positive electrode powder to dissociate lithium ions from it.

2. The lithium battery lithium extraction device according to claim 1, characterized in that: In the feeding module, the feeding mechanism includes a spiral feeding rod and a feeding guide plate. The feeding rod is arranged along the feeding chamber. The feeding rod transfers the lithium battery pole pieces to be processed from the input end of the feeding chamber to the output end of the feeding chamber under the drive of the driving motor. The feeding guide plate is arranged at the output end of the feeding chamber, and is used to guide the lithium battery pole pieces into the pyrolysis stripping chamber of the pyrolysis stripping module.

3. The lithium battery lithium extraction device according to claim 1, characterized in that: The heating and auxiliary air system includes: a heating plate and a hot air trough, the heating plate is used to provide a high-temperature heat source and generate high-temperature hot air, the hot air trough is used to introduce the high-temperature hot air generated by the heating plate into the pyrolysis stripping chamber to pyrolyze the lithium battery pole pieces transmitted in the pyrolysis stripping chamber, and control the air inlet flow of the high-temperature hot air flowing through the hot air trough through the built-in air valve and air inlet plate.

4. The lithium battery lithium extraction device according to claim 3, characterized in that: The adhesive is polyvinylidene fluoride (PVDF), and the temperature range of the high-temperature hot air is 450 degrees Celsius to 650 degrees Celsius.

5. The lithium battery lithium extraction device according to claim 4, characterized in that: In order to control the temperature of the high-temperature hot air and match the corresponding air inlet flow rate, the corresponding relationship between the air inlet flow rate and the temperature of the high-temperature hot air under different lithium battery electrode feed flow rates is set: When the feed flow rate is 0.5 kg / min to 1 kg / min, the air flow rate is (T-450) / 450+1 cubic meter / second, where T is the temperature of the high-temperature hot air; When the feed flow rate is 1 kg / min to 10 kg / min, the air flow rate is (T-450) / 450+1.5 cubic meters / second, where T is the temperature of the high-temperature hot air; When the feed flow rate is 10 kg / min to 30 kg / min, the air flow rate is (T-450) / 450+2 cubic meters / second, where T is the temperature of the high-temperature hot air.

6. The lithium battery lithium extraction device according to claim 1, characterized in that: The flipping mechanism includes a roller, a roller driving unit, and a roller material guide chute. The roller is provided with a discharge hopper. The roller is flipped under the drive of the roller driving unit to flip the lithium battery pole piece during the pyrolysis process. The roller material guide chute adopts a spiral line structure to drive the lithium battery pole piece to be gradually advanced in the roller, and is continuously subjected to high-temperature pyrolysis and airflow during the flipping process, thereby accelerating the decomposition of the binder.

7. The lithium battery lithium extraction device according to claim 1, characterized in that: The lithium battery lithium extraction device is also equipped with a gas distribution system, which includes an air intake pipe and an air distribution pipe. The protective gas is introduced through the air intake pipe and transported to the air distribution pipe. The protective gas is evenly distributed in the feed cavity of the feed module and the pyrolysis stripping cavity of the pyrolysis stripping module through the air distribution holes on the air distribution pipe.

8. The lithium battery lithium extraction device according to claim 1, characterized in that: The cooling and initial separation module includes: a cooling chamber, a blowing assembly, a suction hopper, and a main air duct. By inputting a low-temperature airflow into the cooling chamber, the physical properties of the lithium iron phosphate positive electrode powder and the aluminum collector are changed to facilitate separation. The suction hopper is located above the cooling chamber and is connected to the main air duct. The blowing assembly is used to blow the lithium iron phosphate positive electrode powder into the suction hopper and the main air duct.

9. The lithium battery lithium extraction device according to claim 1, characterized in that: The separation and collection module includes: an analyzer and a linear screen, wherein the analyzer is used to separate lithium iron phosphate positive electrode powder and aluminum current collector, and the linear screen is used to further separate the lithium iron phosphate positive electrode powder separated by the analyzer.

10. The lithium battery lithium extraction device according to claim 1, characterized in that: The ultrasonic piezoelectric lithium extraction module includes: an ultrasonic piezoelectric reaction chamber, an injector, an ultrasonic generator, an ultrasonic transducer, and a piezoelectric generator. The piezoelectric generator adopts a surface piezoelectric coating. The injector is used to inject liquid into the ultrasonic piezoelectric reaction chamber. The ultrasonic generator transmits ultrasonic waves to the piezoelectric generator through the ultrasonic transducer to stimulate the piezoelectric generator to produce a piezoelectric effect, which directly acts on the lithium iron phosphate positive electrode powder in the liquid phase, triggering the release of lithium ions, which gradually dissociate and dissolve to form lithium liquid.

11. The lithium battery lithium extraction device according to claim 1, characterized in that: The lithium battery lithium extraction device also includes: an automatic loading system located at the front end of the feeding module, and / or a lithium liquid screening module located at the rear end of the ultrasonic piezoelectric lithium extraction module.

12. A method for extracting lithium from a lithium battery, characterized in that: Applicable to the lithium battery extraction device as described in any one of claims 1 to 11, the lithium battery extraction method comprises the following steps: The lithium battery pole pieces to be processed are fed into the pyrolysis stripping module by using the feeding module; The pyrolysis stripping module is used to provide high-temperature hot air through a heating and auxiliary air system to pyrolyze the lithium battery pole piece to strip out the lithium iron phosphate positive electrode powder, and the lithium battery pole piece is flipped during the pyrolysis process through a flipping mechanism to accelerate the stripping of the lithium iron phosphate positive electrode powder; Using a cooling and initial separation module to cool and initially separate the stripped mixture of lithium iron phosphate positive electrode powder and aluminum current collector to obtain a material containing lithium iron phosphate positive electrode powder; Using a separation and collection module to separate the material containing lithium iron phosphate positive electrode powder and collect the separated lithium iron phosphate positive electrode powder; and The ultrasonic piezoelectric lithium extraction module uses ultrasound to induce the piezoelectric effect, generating micro-vibrations that act on the lithium iron phosphate positive electrode powder to dissociate lithium ions from it.

Images