Recycling system of waste lithium iron battery

Abstract

The utility model relates to the technical field of lithium battery recycling, in particular to a recycling system of waste lithium iron batteries, which comprises an automatic cutting machine, a feeding port of the automatic cutting machine, a cutting bin and a conveying pipeline are sequentially communicated from top to bottom, the conveying end of the conveying pipeline is a discharging port, and a shunting conveying belt is arranged below the discharging port. The flow dividing conveying belt comprises a first conveying belt and a second conveying belt, the starting end of the first conveying belt is located below the discharging port, the other end of the first conveying belt is located above a feeding port of the crusher, the crusher is connected with the airflow refrigerator and the pyrolyzing furnace, and the pyrolyzing furnace is connected with the horizontal winnowing machine; the horizontal winnowing machine is respectively connected with the separation tank and the pickle liquor tank, the pickle liquor tank is connected with the ultrafiltration, nanofiltration and reverse osmosis separation device, and the ultrafiltration, nanofiltration and reverse osmosis separation device is respectively connected with the lithium precipitation tank and the iron precipitation tank. By using the recycling system provided by the utility model, each element of the waste lithium iron battery can be effectively recycled, and the recycling efficiency is high.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery recycling technology, specifically to a recycling system for waste lithium iron phosphate batteries. Background Technology

[0002] As a novel chemical power source, lithium-ion batteries exhibit unparalleled advantages in the electronics industry, boasting an extremely high market share, accounting for over 80% of the consumer electronics market and becoming the primary energy pillar for these products. In recent years, lithium battery technology has made continuous breakthroughs, with energy density steadily increasing. This has led to explosive growth in demand for lithium-ion batteries in emerging fields such as new energy vehicles and energy storage, resulting in a significant year-on-year increase in lithium-ion battery production and sales. However, in actual use, lithium-ion batteries typically undergo only 500-1000 charge-discharge cycles, with a lifespan of 3-5 years. Discarded lithium-ion batteries contain metals such as iron, nickel, manganese, and lithium, and improper disposal can easily cause serious pollution and resource waste.

[0003] There are several recycling technologies for spent lithium iron phosphate (LFP) batteries. One method involves degumming the positive electrode after discharge by heating and soaking it in N-methyl-2-pyrrolidone solvent, followed by centrifugation to separate the aluminum foil and lithium iron phosphate. Another method involves degumming the positive electrode after discharge by aerobic / anaerobic calcination or alternating hot and cold soaking, followed by soaking in sodium hydroxide solution to remove aluminum, thus obtaining lithium iron phosphate powder. These methods are mostly wet processes or a combination of wet and pyrometallurgical methods, primarily focusing on the recovery of lithium iron phosphate powder. They fail to perform detailed classification and recycling of iron and lithium elements, and do not fully explore the potential value of materials such as aluminum foil, resulting in incomplete recycling. Utility Model Content

[0004] To address the shortcomings of existing technologies in recycling waste lithium iron phosphate batteries, which lack precise methods and fail to effectively classify and recycle the aluminum, iron, and lithium elements, this invention provides a recycling system for waste lithium iron phosphate batteries.

[0005] The technical solution of this utility model is as follows:

[0006] A recycling system for waste lithium iron phosphate batteries includes an automatic cutting machine. The automatic cutting machine's feed inlet, cutting chamber, and transport pipe are connected sequentially from top to bottom. Cutting blades are horizontally arranged inside the cutting chamber, and fixed grippers are installed above the cutting blades. The transport pipe ends at the discharge outlet, and a diversion conveyor belt is installed below the discharge outlet. The diversion conveyor belt includes a first transmission belt and a second transmission belt. The starting end of the first transmission belt is below the discharge outlet, and the other end of the first transmission belt is above the feed inlet of a crusher. The crusher is connected to an airflow chiller and a pyrolysis furnace, respectively. The pyrolysis furnace is connected to a horizontal air classifier, which is connected to a separation tank and an acid leaching tank. The acid leaching tank is equipped with a heating device and a stirring device. The acid leaching tank is connected to an ultrafiltration / nanofiltration / reverse osmosis separation device, which is connected to a lithium precipitation tank and an iron precipitation tank, respectively.

[0007] Furthermore, a slide rail is laid above the automatic cutting machine, allowing the robotic arm to extend and slide within the slide rail.

[0008] Furthermore, the starting end of the second transmission belt is parallel to the starting end of the first transmission belt, and the other end of the second transmission belt is connected to the outer casing recycling bin.

[0009] Furthermore, the crushing chamber of the crusher is sealed to the airflow chiller through the first pipe.

[0010] Furthermore, the discharge port of the crusher is connected to the feed port of the pyrolysis furnace through a second pipe.

[0011] Furthermore, one of the discharge ports of the horizontal air classifier is connected to the separation tank via a third pipe.

[0012] Furthermore, another outlet of the horizontal air classifier is connected to the acid leaching tank via a fourth pipe.

[0013] The beneficial effects of this utility model are as follows:

[0014] Waste lithium iron phosphate batteries do not need to be fully discharged. A continuous supply of low-temperature nitrogen gas to the crusher via an airflow chiller ensures safety during the crushing process. Air separation separates the batteries into a mixture of aluminum foil particles and negative electrode graphite particles, oxidized positive electrode material particles, and copper foil particles, according to their weight. Filtration of the acid leaching solution using ultrafiltration, nanofiltration, and reverse osmosis separation devices effectively separates residual organic macromolecular waste, iron ions, and lithium ions. The waste lithium iron phosphate battery recycling system provided by this invention is simple to operate, avoids organic solvent extraction, and achieves effective recovery of all elements from waste lithium iron phosphate batteries with high recycling efficiency. Attached Figure Description

[0015] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the present invention.

[0017] In the diagram, 1-robotic arm, 2-automatic cutting machine, 3-diversion conveyor belt, 4-airflow chiller, 5-crusher, 6-pyrolysis furnace, 7-horizontal air classifier, 8-separation tank, 9-acid leaching tank, 10-ultrafiltration, nanofiltration and reverse osmosis separation device, 11-lithium precipitation tank, 12-iron precipitation tank. Detailed Implementation

[0018] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0019] Example 1

[0020] For reference Figure 1 A recycling system for waste lithium iron phosphate batteries includes an automatic cutting machine 2. A slide rail is installed above the automatic cutting machine 2, allowing a robotic arm 1 to slide and extend within the rail. The feed inlet, cutting chamber, and transport pipe of the automatic cutting machine 2 are connected sequentially from top to bottom. A cutting blade is horizontally arranged inside the cutting chamber, and a fixed gripper is installed above the cutting blade. The end of the transport pipe is the discharge outlet. A diversion conveyor belt 3 is installed below the discharge outlet. The diversion conveyor belt 3 includes a first transmission belt and a second transmission belt. The starting end of the first transmission belt is below the discharge outlet, and the starting end of the second transmission belt is parallel to the starting end of the first transmission belt. The other end of the second transmission belt is connected to the outer casing recycling... The crushing chamber of the crusher 5 is connected to the airflow chiller 4 via a first pipe. The discharge port of the crusher 5 is connected to the inlet of the pyrolysis furnace 6 via a second pipe. The pyrolysis furnace 6 is connected to the horizontal air classifier 7. One discharge port of the horizontal air classifier 7 is connected to the separation tank 8 via a third pipe. The other discharge port of the horizontal air classifier 7 is connected to the acid leaching tank 9 via a fourth pipe. The acid leaching tank 9 is equipped with a heating device and a stirring device. The acid leaching tank 9 is connected to the ultrafiltration, nanofiltration and reverse osmosis separation device 10. The ultrafiltration, nanofiltration and reverse osmosis separation device 10 is connected to the lithium precipitation tank 11 and the iron precipitation tank 12 respectively.

[0021] The specific usage process is as follows:

[0022] The waste lithium iron phosphate batteries, with their covers facing down, are picked up by robotic arm 1 and moved along a slide rail to the feed inlet of automatic cutting machine 2. They then extend into the cutting chamber of automatic cutting machine 2, where a fixed gripper secures the waste lithium iron phosphate batteries. The cutting blade then horizontally cuts the secured batteries. After the cover is cut off, the fixed gripper releases, and the cut waste lithium iron phosphate batteries fall into the transport pipe. Outside the outlet, workers manually separate the battery cells from the casings. The casings and covers are placed on the second transmission belt of the diversion conveyor 3 and sent to the casing recycling bin. The battery cells are placed on the first transmission belt of the diversion conveyor 3 and sent to crusher 5 for crushing. Simultaneously, a chiller 4 continuously supplies low-temperature nitrogen to crusher 5, ensuring the safety of undischarged battery cells during the crushing process under certain temperature and pressure conditions. After crushing, mixed slag A is obtained.

[0023] Mixed slag A is sent to pyrolysis furnace 6 for high-temperature roasting to remove electrolyte and positive and negative electrode binders, resulting in mixed slag B. During the high-temperature roasting process, the lithium iron phosphate cathode material is fully oxidized by air. Mixed slag B includes copper foil particles, aluminum foil particles, negative electrode graphite particles, and oxidized cathode material particles. Mixed slag B is then conveyed to a horizontal air classifier 7 for air classification, obtaining a mixture of aluminum foil particles and negative electrode graphite particles, oxidized cathode material particles, and copper foil particles in order of weight. The separated copper can be directly recycled. The mixture of aluminum foil particles and negative electrode graphite particles is fed into a separation tank containing organic solvent through a third pipe via one outlet of the horizontal air classifier 7. Utilizing the density difference between the aluminum foil particles and negative electrode graphite particles, the two are separated and recycled. The oxidized cathode material particles are fed into the acid leaching tank 9 through another outlet of the horizontal air classifier 7 via the fourth pipe. They are heated and stirred in the acid solution to leach out valuable metal elements, yielding an acid leaching solution. This solution then enters the ultrafiltration, nanofiltration, and reverse osmosis separation device 10, where it is filtered through both ultrafiltration and nanofiltration membranes. Ultrafiltration removes residual organic matter and other large molecules, reducing clogging and contamination of subsequent membranes. Nanofiltration retains iron and phosphate ions, which are enriched on the concentrate side, while lithium ions enter the desalination. After further concentration via reverse osmosis, a lithium-containing concentrated solution and a mixed concentrated solution containing other iron ions are obtained. The lithium-containing concentrated solution enters the lithium precipitation tank 11 containing a lithium precipitant, where lithium precipitate is obtained. The mixed concentrated solution containing other iron ions enters the iron precipitation tank 12 containing an alkaline substance, where an iron precipitate is obtained.

[0024] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A recycling system for waste lithium iron phosphate batteries, comprising an automatic cutting machine (2), characterized in that, The feed inlet, cutting chamber and transport pipe of the automatic cutting machine (2) are connected from top to bottom. The cutting chamber is equipped with horizontal cutting blades. A fixed gripper is installed above the cutting blades. The end of the transport pipe is the discharge port. A diversion conveyor belt (3) is installed below the discharge port. The diversion conveyor belt (3) includes a first transmission belt and a second transmission belt. The starting end of the first transmission belt is below the discharge port. The other end of the first transmission belt is above the feed inlet of the crusher (5). The crusher (5) is connected to the airflow chiller (4) and the pyrolysis furnace (6) respectively. The pyrolysis furnace (6) is connected to the horizontal air classifier (7). The horizontal air classifier (7) is connected to the separation tank (8) and the acid leaching tank (9) respectively. The acid leaching tank (9) is equipped with a heating device and a stirring device. The acid leaching tank (9) is connected to the ultrafiltration nanofiltration reverse osmosis separation device (10). The ultrafiltration nanofiltration reverse osmosis separation device (10) is connected to the lithium precipitation tank (11) and the iron precipitation tank (12) respectively.

2. The recycling system for waste lithium iron phosphate batteries as described in claim 1, characterized in that, A slide rail is laid above the automatic cutting machine (2) for the robot arm (1) to slide and extend within the slide rail.

3. The recycling system for waste lithium iron phosphate batteries as described in claim 1, characterized in that, The starting end of the second transmission belt is parallel to the starting end of the first transmission belt, and the other end of the second transmission belt is connected to the outer casing recycling bin.

4. The recycling system for waste lithium iron phosphate batteries as described in claim 1, characterized in that, The crushing chamber of the crusher (5) is sealed to the airflow chiller (4) through the first pipe.

5. The recycling system for waste lithium iron phosphate batteries as described in claim 1, characterized in that, The discharge port of the crusher (5) is connected to the feed port of the pyrolysis furnace (6) through a second pipe.

6. The recycling system for waste lithium iron phosphate batteries as described in claim 1, characterized in that, One outlet of the horizontal air separator (7) is connected to the separation tank (8) via a third pipe.

7. The recycling system for waste lithium iron phosphate batteries as described in claim 6, characterized in that, Another outlet of the horizontal air classifier (7) is connected to the acid leaching tank (9) via a fourth pipe.

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