System and method for separating active material and substrate of positive plate of lithium battery

Abstract

The invention discloses a system and a method for separating an active material and a substrate of a lithium battery positive plate. The system comprises a material separator, a mesh belt conveyor, dewatering and drying equipment, a vibrating screen classifier, water circulation equipment, filtering equipment, a dryer and washing equipment, the material separator is used for separating positive electrode powder on a lithium battery positive plate from a substrate aluminum foil, the separated positive electrode powder presents three different particle size ranges, and the separated positive electrode powder is respectively defined as sheet-shaped positive electrode powder, large-particle positive electrode powder and small-particle positive electrode powder according to the sequence of the particle sizes from large to small; the mesh belt conveyor filters out flaky positive electrode powder from the reaction liquid and conveys the flaky positive electrode powder to dewatering and drying equipment for dewatering and drying treatment; filtering out large-particle positive electrode powder by the filtering equipment, and filtering out small-particle positive electrode powder by the residual reaction liquid in the washing equipment; the washing equipment is connected to the reaction tank through the water circulation equipment. According to the invention, the waste lithium battery positive plate active material and the substrate can be separated and recycled in a clean, efficient and high-grade manner.

Description

Technical Field

[0001] The present invention relates to the technical field of recycling and treatment of waste lithium batteries, and particularly relates to a separation system and method for the active material and the substrate of a lithium battery positive electrode sheet. Background Art

[0002] With the development of global electrification, new energy has shown explosive growth. The resulting waste lithium batteries not only contain a large amount of precious metals but also a large amount of toxic substances. If waste lithium batteries cannot be properly disposed of, it will not only cause waste of resources but also serious environmental pollution. Among them, the positive electrode sheet of a lithium battery contains various high-value metals and is the component with the highest cost and the highest recycling economic value in a lithium battery. Clean, efficient, and high-grade separation and recycling of the active material and the substrate of the waste lithium battery positive electrode sheet is the key part of realizing the recycling of waste lithium-ion power batteries.

[0003] The invention with the publication number CN219168518U discloses a method for treating a positive electrode sheet by means of pole piece crushing. The inventions with the publication numbers CN 112599877 B, CN 114473769 A, and CN 215541461 U propose to separate the active material and the aluminum foil by means of mechanical grinding; the invention with the publication number CN116216674A proposes to separate the materials by acid leaching the positive electrode sheet, the invention with the publication number CN115863813A proposes to recycle the positive electrode material of a lithium iron phosphate manganese battery by means of high-temperature plasma technology, and the inventions with the publication numbers CN114639887A, CN110767956A, and CN116177516A propose to strip the materials and the current collector by means of soaking the positive electrode sheet with an organic solvent. However, the foregoing technical solutions all have unacceptable defects at present. For example, it is very difficult to completely separate by mechanical stripping methods, resulting in difficult subsequent impurity removal; high-temperature heat treatment has high energy consumption and generates a large amount of waste gas; acid leaching and alkali leaching have complex processes, low recovery rates, and difficult treatment of waste liquid; organic solvents are toxic and expensive, and the cost is relatively high, etc. Summary of the Invention

[0004] The purpose of the present invention is to propose a separation system and method for the active material and the substrate of a lithium battery positive electrode sheet, which can clean, efficiently, and highly grade separate and recycle the active material and the substrate of the waste lithium battery positive electrode sheet.

[0005] To achieve the above technical purpose, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention discloses a separation system for the active material and the substrate of a lithium battery positive electrode sheet, and the separation system includes a material separator, a mesh belt conveyor, a water removal and drying device, a vibrating screen, a water circulation device, a filtering device, a dryer, and a washing device;

[0007] The material separator uses the reaction liquid in the reaction tank to soak and ultrasonically treat the positive electrode sheet of the lithium battery, separating the positive electrode powder on the positive electrode sheet of the lithium battery from the substrate aluminum foil. The separated positive electrode powder presents three different particle size ranges, which are defined as flaky positive electrode powder, large particle positive electrode powder, and small particle positive electrode powder in order from largest to smallest particle size;

[0008] The mesh belt conveyor is connected between the material separator and the water removal and drying equipment, and is used to filter out the flaky positive electrode powder from the reaction liquid and transport it to the water removal and drying equipment for water removal and drying treatment;

[0009] The vibrating screen adopts a two-layer structure. Its inlet is located on the upper layer and is connected to the outlet of the water removal and drying equipment. The upper layer outlet is connected to the aluminum foil recovery device, and the lower layer outlet is connected to the positive electrode powder recovery device;

[0010] The filtration equipment is connected to the reaction tank and filters the reaction liquid containing positive electrode powder transported from the reaction tank. The filtered large particle positive electrode powder is directly sent to the dryer for drying, and the remaining reaction liquid enters the washing equipment to further filter out the small particle positive electrode powder; The washing equipment includes a positive electrode powder outlet and a reaction liquid outlet. The positive electrode powder outlet is connected to the dryer, and the reaction liquid outlet is connected to the reaction tank through a water circulation device.

[0011] Further, the separation system adopts a two-layer split design. The upper layer equipment includes a material separator, a water removal and drying equipment, and a vibrating screen. The lower layer equipment includes a supplementary liquid medicine system, a filtration equipment, a washing equipment, a dryer, and a water circulation equipment. The upper and lower layers are separated by a support frame.

[0012] Further, the material separator includes a reaction tank, an ultrasonic vibration plate, an industrial heating rod, a liquid level sensor, a temperature sensor, and a concentration detection sensor;

[0013] The ultrasonic vibration plate is installed on the inner side wall of the reaction tank to ultrasonically treat the positive electrode sheet of the lithium battery in the reaction tank;

[0014] The industrial heating rod is immersed in the reaction tank to heat the reaction liquid;

[0015] The liquid level sensor, temperature sensor, and concentration detection sensor are respectively used to measure the liquid level, temperature, and concentration of the reaction liquid.

[0016] Further, the first end of the mesh belt conveyor is located in the reaction tank, and the positive electrode sheet of the lithium battery is located on it; The second end of the mesh belt conveyor penetrates through the water removal and drying equipment and extends to the end of the water removal and drying equipment.

[0017] Further, the water removal and drying equipment includes a water removal machine and a tunnel dryer;

[0018] The water remover includes a box body, an industrial hot air blower, and a number of hot air pipes distributed on the inner wall of the box body; the mesh belt conveyor penetrates the box body, and the industrial hot air blower blows hot air at a preset temperature into the hot air pipes at a set wind speed. The hot air blows through the air holes on the hot air pipes onto the flaky positive electrode powder and aluminum foil on the mesh belt conveyor. After removing the surface moisture on the aluminum foil and flaky positive electrode powder, the aluminum foil and flaky positive electrode powder are sent into a tunnel dryer for drying.

[0019] Further, the filtering device is a drum screen.

[0020] Further, the washing device uses a plate filter press.

[0021] Further, the separation system further includes a supplementary liquid medicine system, which is connected to the reaction tank.

[0022] In a second aspect, the present invention discloses a method for separating the active material of a lithium battery positive electrode sheet from a substrate, and the method includes the following steps:

[0023] Add water and reaction liquid medicine to the reaction tank of the material separator in sequence until the liquid level and liquid medicine concentration in the reaction tank reach the corresponding set values; heat the reaction tank until the mixed liquid in the reaction tank reaches the set temperature;

[0024] Feed the positive electrode sheet material into the reaction tank of the material separator at a set feeding speed and place it on the mesh belt conveyor. After being soaked in the mixed liquid and assisted by ultrasonic vibration, the positive electrode powder on the positive electrode sheet is gradually separated from the substrate aluminum foil; the separated positive electrode powder presents three different particle size ranges, which are defined as flaky positive electrode powder, large particle positive electrode powder, and small particle positive electrode powder in the order from large to small particle size; the large particle and small particle positive electrode powders pass through the mesh belt conveyor and fall to the lower layer of the separation tank, and the flaky positive electrode powder remains on the mesh of the mesh belt conveyor, leaves the separation tank together with the aluminum foil and enters the water remover to remove the surface moisture;

[0025] Send the flaky positive electrode powder and aluminum foil with surface moisture removed into a tunnel dryer for drying, and the dried material falls onto the screen of a vibrating screen;

[0026] The screen starts to vibrate, and the flaky positive electrode powder is broken into small flakes under the vibration and collision of the screen, passes through the mesh holes of the screen and falls to the lower layer of the vibrating screen, and further enters the positive electrode powder recovery bag; the aluminum foil remains on the upper layer of the screen and is transported to the aluminum foil recovery bag;

[0027] Monitor the content of positive electrode powder in the reaction tank. When the preset content is reached, transfer the reaction liquid mixed with positive electrode powder to a filter screen to filter out large particle positive electrode powder, and send the remaining filtrate to a washing device to filter out small particle positive electrode powder; the filtered large particle positive electrode powder and small particle positive electrode powder are sent to a drying device for drying, and after drying, they are sent into the positive electrode powder recovery bag. The reaction liquid after two-stage filtration passes through a water circulation device and returns to the reaction tank again.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] The separation system and method for the active material of the lithium battery cathode plate and the substrate of the present invention have a simple process, and have the advantages of environmental protection, cleanliness, high efficiency, high quality, etc., and can maximize the recycling value and economic value of the recycled materials. Brief Description of the Drawings

[0030] Figure 1 is a schematic structural diagram of the separation system for the active material of the lithium battery cathode plate and the substrate of the present invention;

[0031] Figure 2 is a process flow diagram of the separation of the active material of the lithium battery cathode plate and the substrate of the present invention;

[0032] Figure 3 is a schematic diagram of the positive electrode powder after the separation of the active material of the lithium battery cathode plate and the substrate of the present invention;

[0033] Figure 4 is a schematic diagram of the third-party test results of the positive electrode powder recovered after separation of the present invention. Detailed Description of the Invention

[0034] The following further describes the embodiments of the present invention in detail with reference to the accompanying drawings.

[0035] The present invention discloses a separation system for the active material of the lithium battery cathode plate and the substrate. The separation system includes a material separator, a mesh belt conveyor, a water removal and drying device, a vibrating screen, a water circulation device, a filtering device, a dryer and a washing device;

[0036] The material separator uses the reaction liquid in the reaction tank to soak and ultrasonically treat the lithium battery cathode plate, separates the positive electrode powder on the lithium battery cathode plate from the substrate aluminum foil, and the separated positive electrode powder presents three different particle size ranges, which are defined as flaky positive electrode powder, large particle positive electrode powder and small particle positive electrode powder in order from large to small particle size;

[0037] The mesh belt conveyor is connected between the material separator and the water removal and drying device, and is used to filter out the flaky positive electrode powder from the reaction liquid and transport it to the water removal and drying device for water removal and drying treatment;

[0038] The vibrating screen adopts a two-layer structure, its inlet is located on the upper layer and is connected to the outlet of the water removal and drying device, the upper layer outlet is connected to the aluminum foil recovery device, and the lower layer outlet is connected to the positive electrode powder recovery device;

[0039] The filtration device is connected to the reaction tank and filters the reaction liquid containing positive electrode powder delivered from the reaction tank. The large-particle positive electrode powder filtered out is directly sent to a dryer for drying, and the remaining reaction liquid enters a washing device to further filter out small-particle positive electrode powder. The washing device includes a positive electrode powder outlet and a reaction liquid outlet. The positive electrode powder outlet is connected to the dryer, and the reaction liquid outlet is connected to the reaction tank through a water circulation device.

[0040] See Figure 1 , the separation system of the present invention adopts a split design with upper and lower layers. The upper-layer equipment mainly includes a material separator 1, a water remover 2, a tunnel dryer 3, and a vibrating screen 4. The lower-layer equipment mainly includes a supplementary liquid medicine system 5, a filtration device 7, a washing device 8, a drying device 10, and a water circulation device 6. The upper and lower layers are separated by a support frame 11.

[0041] The material separator 1 is composed of a separation tank, a mesh belt conveyor, an ultrasonic vibrating plate, an industrial heating rod, a liquid level sensor, a temperature sensor, a concentration detection sensor, etc. The mesh belt conveyor of the material separator 1 passes through the water remover 2 and extends out of the end of the water remover 2. The water remover 2 is connected to the material separator 1. The water remover is composed of an upper box body, a lower box body, an industrial hot air blower, and a number of hot air pipes, etc. The filtration device 7 can adopt a filtration screening device, such as a drum screen, etc. The washing device 8 can adopt a filter press, and the specific form can be one of a plate and frame filter press, a belt filter press, etc.; the drying device 10 can be one of a vibrating fluidized bed, a tunnel dryer, a flash dryer, etc.

[0042] Based on the above-mentioned separation system, the present invention discloses a method for separating the active material of a lithium battery positive electrode sheet from a substrate, as Figure 2 shown, the separation process is divided into feeding, separation, water removal and drying, screening and recovery, filtration, drying, recovery and packaging, etc.

[0043] Feeding process: It includes feeding water into the reaction tank, supplementing liquid medicine to the reaction tank, and feeding the electrode sheet material into the reaction tank. Finally, the reaction tank contains a mixed reaction liquid. Specifically, the water circulation device 6 first adds water to the reaction tank of the material separator 1. After the liquid level in the reaction tank reaches the set value, the supplementary liquid medicine system 5 adds reaction liquid medicine to the reaction tank of the material separator 1. After the concentration of the reaction liquid medicine in the reaction tank reaches the set value, the reaction tank starts to heat the mixed liquid in the reaction tank to the set temperature.

[0044] Separation process: The positive electrode sheet material is conveyed to the reaction tank of the material separator at a set feeding speed and placed on the mesh belt conveyor. After being soaked in the mixed liquid and assisted by ultrasonic vibration, the positive electrode powder on the positive electrode sheet is gradually separated from the substrate aluminum foil. The separated positive electrode powder presents three different particle size ranges, which are defined as flaky positive electrode powder, large particle positive electrode powder, and small particle positive electrode powder in the order from large to small particle size. The large particle and small particle positive electrode powders pass through the mesh belt conveyor and fall to the lower layer of the separation tank, while the flaky positive electrode powder remains on the mesh of the mesh belt conveyor.

[0045] Water removal and drying process: The flaky positive electrode powder and the aluminum foil leave the separation tank together and enter the water remover. In the water remover 2, the industrial hot air blower blows hot air at a certain temperature into the hot air pipe at a set wind speed. The hot air blows through the air holes on the hot air pipe towards the flaky positive electrode powder and the aluminum foil on the mesh belt conveyor, removing most of the moisture on the aluminum foil and the flaky positive electrode powder. Subsequently, it enters the tunnel dryer 3 for drying. The temperature inside the cavity of the tunnel dryer 3 reaches the set drying temperature, and the flaky positive electrode powder and the aluminum foil on the conveyor belt of the dryer are quickly dried under the action of high temperature. The dried materials fall onto the screen of the vibrating screen.

[0046] Screening and recycling process: Through the vibration of the vibrating screen 4, the flaky positive electrode powder breaks into small flakes under the vibration and collision of the screen, passes through the mesh holes of the screen and falls to the lower layer of the vibrating screen, and further enters the positive electrode powder recovery bag; the aluminum foil remains on the upper layer of the screen and is transported to the aluminum foil recovery bag.

[0047] The filtration process and the drying process are set for the large particle positive electrode powder and the small particle positive electrode powder. After a period of separation reaction, a certain amount of large particle and small particle positive electrode powders accumulate in the reaction tank of the material separator 4 and need to be centrally processed. By monitoring the content of the positive electrode powder in the reaction tank, when the preset content is reached, the reaction liquid mixed with the positive electrode powder is transported to the filter screen 7 to filter out the large particle positive electrode powder, and the remaining filtrate is sent to the washing device 8 to filter out the small particle positive electrode powder; the filtered large particle positive electrode powder and small particle positive electrode powder are sent to the drying device 10 for drying, and after drying, they are sent into the positive electrode powder recovery bag. The reaction liquid after two-stage filtration returns to the reaction tank through the water circulation device.

[0048] Recovery and packaging: Recover the materials in the positive electrode powder recovery bag and the aluminum foil recovery bag.

[0049] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments as well as all changes and modifications falling within the scope of the present application.

[0050] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to cover these modifications and variations.

Claims

1. A separation system for the active material of a lithium battery cathode plate and a substrate, characterized in that The separation system includes a material separator, a mesh belt conveyor, a water removal and drying device, a vibrating screen, a water circulation device, a filtering device, a dryer, and a washing device; The material separator uses the reaction liquid in the reaction tank to soak and ultrasonically treat the positive electrode sheet of the lithium battery, separating the positive electrode powder on the positive electrode sheet of the lithium battery from the substrate aluminum foil. The separated positive electrode powder presents three different particle size ranges, which are defined as flaky positive electrode powder, large particle positive electrode powder, and small particle positive electrode powder in order from largest to smallest particle size; The mesh belt conveyor is connected between the material separator and the water removal and drying device, and is used to filter out the flaky positive electrode powder from the reaction liquid and transport it to the water removal and drying device for water removal and drying treatment; The vibrating screen adopts a two-layer structure. Its inlet is located on the upper layer and is connected to the outlet of the water removal and drying device. The upper layer outlet is connected to the aluminum foil recovery device, and the lower layer outlet is connected to the positive electrode powder recovery device; The filtering device is connected to the reaction tank and filters the reaction liquid containing positive electrode powder transported from the reaction tank. The filtered large particle positive electrode powder is directly sent to the dryer for drying, and the remaining reaction liquid enters the washing device to further filter out the small particle positive electrode powder; The washing device includes a positive electrode powder outlet and a reaction liquid outlet. The positive electrode powder outlet is connected to the dryer, and the reaction liquid outlet is connected to the reaction tank through a water circulation device.

2. The separation system of the lithium battery cathode active material and the substrate according to claim 1, wherein The separation system adopts an upper and lower two-layer split design. The upper layer equipment includes a material separator, a water removal and drying device, and a vibrating screen. The lower layer equipment includes a supplementary liquid medicine system, a filtering device, a washing device, a dryer, and a water circulation device. The upper and lower layers are separated by a support frame.

3. The separation system of the lithium battery cathode active material and the substrate according to claim 1, characterized in that, The material separator includes a reaction tank, an ultrasonic vibration plate, an industrial heating rod, a liquid level sensor, a temperature sensor, and a concentration detection sensor; The ultrasonic vibration plate is installed on the inner side wall of the reaction tank to ultrasonically treat the positive electrode sheet of the lithium battery in the reaction tank; The industrial heating rod is immersed in the reaction tank to heat the reaction liquid; The liquid level sensor, temperature sensor, and concentration detection sensor are respectively used to measure the liquid level, temperature, and concentration of the reaction liquid.

4. The separation system of the lithium battery cathode active material and the substrate according to claim 1, wherein The first end of the mesh belt conveyor is located in the reaction tank, and the positive electrode sheet of the lithium battery is located on it; The second end of the mesh belt conveyor penetrates through the water removal and drying device and extends to the end of the water removal and drying device.

5. The separation system of the lithium battery cathode active material and the substrate according to claim 1, wherein, The water removal and drying device includes a water remover and a tunnel dryer; The water remover includes a box body, an industrial hot air blower, and a number of hot air pipes distributed on the inner wall of the box body; The mesh belt conveyor penetrates through the box body. The industrial hot air blower blows hot air at a preset temperature into the hot air pipes at a set wind speed. The hot air blows through the air holes on the hot air pipes onto the flaky positive electrode powder and aluminum foil on the mesh belt conveyor. After removing the surface moisture on the aluminum foil and flaky positive electrode powder, the aluminum foil and flaky positive electrode powder are sent to the tunnel dryer for drying.

6. The separation system for the active material of the lithium battery cathode and the substrate according to claim 1, characterized in that, The filtering device is a drum screen.

7. The separation system of the lithium battery cathode active material and the substrate according to claim 1, characterized in that, The washing device adopts a filter press.

8. The separation system of the lithium battery cathode active material and the substrate according to claim 1, characterized in that, The separation system further includes a supplementary liquid medicine system, which is connected to the reaction tank.

9. A method for separating the active material of the positive electrode plate of a lithium battery from the substrate based on the system according to any one of claims 1-8, characterized in that, The method includes the following steps: Add water and reaction liquid medicine to the reaction tank of the material separator in sequence until the liquid level and liquid medicine concentration in the reaction tank reach the corresponding set values; Heat the reaction tank until the mixed liquid in the reaction tank reaches the set temperature; The positive electrode sheet material is conveyed to the reaction tank of the material separator at the set feeding speed and placed on the mesh belt conveyor. After being soaked in the mixed liquid and assisted by ultrasonic vibration, the positive electrode powder on the positive electrode sheet is gradually separated from the substrate aluminum foil. The separated positive electrode powder presents three different particle size ranges, which are defined as flaky positive electrode powder, large particle positive electrode powder, and small particle positive electrode powder in the order from large to small particle size. The large particle and small particle positive electrode powders pass through the mesh belt conveyor and fall to the lower layer of the separation tank, while the flaky positive electrode powder remains on the mesh of the mesh belt conveyor, leaves the separation tank together with the aluminum foil and enters the water remover to remove the surface moisture. The flaky positive electrode powder and aluminum foil with surface moisture removed are sent into a tunnel dryer for drying, and the dried material falls onto the screen of a vibrating screen. The screen starts to vibrate. The flaky positive electrode powder is broken into small flakes under the vibration and collision of the screen, passes through the mesh holes of the screen and falls to the lower layer of the vibrating screen, and further enters the positive electrode powder recovery bag. The aluminum foil remains on the upper layer of the screen and is transported to the aluminum foil recovery bag. The positive electrode powder content in the reaction tank is monitored. When the preset content is reached, the reaction liquid mixed with the positive electrode powder is transported to a filter screen to filter out the large particle positive electrode powder, and the remaining filtrate is sent to a washing device to filter out the small particle positive electrode powder. The filtered large particle and small particle positive electrode powders are sent into a drying device for drying, and after drying, they are sent into the positive electrode powder recovery bag. The reaction liquid after two-stage filtration returns to the reaction tank through a water circulation device.

Images