Waste lithium ion battery recovery system

Abstract

The utility model belongs to the field of new energy, and discloses a waste lithium ion battery recycling system which comprises a shredding unit, a recycling unit and a recycling unit, the drying unit is used for heating the shredded product so as to volatilize the electrolyte, and collecting the volatilized electrolyte and a retained first solid; the hammer breaking unit is used for carrying out breaking operation on the first solid object, so that black powder on the first solid object falls off, and the first solid object is further broken; and the post-processing subsystem is used for sorting the shell, the diaphragm, the pole piece and the black powder in the second solid. According to the system, the shredding unit, the drying unit and the hammer breaking unit are adopted for pre-treating the lithium ion battery, the obtained second solid is used for follow-up sorting, the nitrogen consumption can be effectively reduced, black powder can fall off and be collected as much as possible before material sorting, and the follow-up material sorting difficulty is reduced.

Description

Technical Field

[0001] The utility model relates to the field of new energy, and in particular to a waste lithium-ion battery recycling system. Background Art

[0002] In the existing waste lithium-ion battery recycling process, the waste lithium-ion batteries generally need to be crushed first and then sorted and recycled into various substances.

[0003] First, shredding the material is a common process, as shown in the following:

[0004] CN113426804A discloses a physical separation and enrichment method for resource components of discarded lithium-ion batteries, which involves first shredding, then low-temperature drying, and then magnetic separation and air separation to separate the outer shell and diaphragm.

[0005] The problem with this solution is that direct air separation and magnetic separation after low-temperature drying can easily lead to a large amount of black powder being carried away;

[0006] CN208526928U discloses a device for processing waste lithium-ion batteries, which is first shredded and then crushed.

[0007] The problem with this solution is that crushers are generally high-speed equipment, and the sealing of high-speed equipment is difficult to control and has poor stability. In order to solve the sealing problem, a large flow of inert gas is generally used to maintain an inert environment in the high-speed equipment, and the amount of inert gas used is large.

[0008] Based on this, the technical problem solved in this case is: how to simplify the lithium-ion battery recycling process to reduce nitrogen usage and increase the black powder recovery rate. Utility Model Content

[0009] The purpose of the utility model is to provide a waste lithium-ion battery recycling system, which adopts a shredding unit, a drying unit, and a hammer crushing unit to pre-treat the lithium-ion batteries, and the obtained second solid is used for subsequent sorting. It can effectively reduce the nitrogen consumption, make the black powder fall off and be collected as much as possible before the material is sorted, and reduce the difficulty of subsequent material sorting.

[0010] To achieve the above objectives, the present invention provides the following technical solutions: a waste lithium-ion battery recycling system, comprising:

[0011] Shredding unit: used to shred waste lithium-ion batteries to obtain shredded products;

[0012] Drying unit: heating the shredded product to volatilize the electrolyte, and collecting the volatilized electrolyte and the remaining first solid matter;

[0013] Hammer crushing unit: used for crushing the first solid object to remove the black powder on the first solid object and further crush the first solid object to obtain the first black powder and the second solid object;

[0014] Post-processing subsystem: used to separate the shell, diaphragm, electrode and black powder in the second solid object.

[0015] In the above waste lithium-ion battery recycling system, the shredding unit includes a first double-shaft shredder and a second double-shaft shredder; the material shredding size of the first double-shaft shredder is larger than the material shredding size of the second double-shaft shredder.

[0016] In the above waste lithium-ion battery recycling system, the blade thickness of the first double-shaft shredder is 25-50 mm; the blade thickness of the second double-shaft shredder is 10-25 mm.

[0017] In the above-mentioned waste lithium-ion battery recycling system, the first biaxial shredder, the second biaxial shredder, and the drying unit are each independently connected to an inert gas control module; the inert gas control module is used to maintain an inert gas atmosphere in the corresponding first biaxial shredder, the second biaxial shredder, and the drying unit.

[0018] In the above waste lithium-ion battery recycling system, the first double-shaft shredder, the second double-shaft shredder, and the drying unit are arranged in sequence from top to bottom; a gate valve is provided between the second double-shaft shredder and the drying unit.

[0019] In the above-mentioned waste lithium-ion battery recycling system, the hammer crushing unit includes a hammer crusher and a first screening machine, the hammer crusher is used to crush the first solid matter; the first screening machine is used to screen the material processed by the hammer crusher to obtain a first oversize material and a first undersize material;

[0020] The first oversize material is the second solid material; the first undersize material is the first black powder.

[0021] In the above waste lithium-ion battery recycling system, the post-processing subsystem includes an airflow sorting unit, a crusher, a second screening machine, a grinder, a third screening machine, and a heating furnace;

[0022] The airflow separation unit is used to remove the diaphragm and the shell in the second solid matter to obtain a third solid matter;

[0023] The crusher is used to crush the third solid object to obtain a fourth solid object;

[0024] The second screening machine screens the fourth solid matter to obtain a second oversize material mainly composed of metal particles and a second undersize material mainly composed of black powder;

[0025] The grinder is used to grind the second oversize material to obtain a fifth solid material;

[0026] The third screening machine is used to screen the fifth solid matter to obtain a third oversize material and a third undersize material containing black powder as the main material;

[0027] The heating furnace is used to volatilize VOC in at least one of the first black powder, the second undersize material, and the third undersize material.

[0028] In the above waste lithium-ion battery recycling system, the post-processing subsystem further includes a sorting machine, which can separate different types of metal particles based on the different specific gravities of the metal particles in the third oversize material.

[0029] The second screening machine has a double-layer screen, which includes an upper screen and a lower screen. The specification of the upper screen is 5 to 10 meshes; the specification of the lower screen is 40 to 120 meshes.

[0030] In the above-mentioned waste lithium-ion battery recycling system, the airflow sorting unit includes multiple Z-type airflow sorters connected in sequence; among the multiple Z-type airflow sorters, at least one Z-type airflow sorter is used to sort the shell, and at least one Z-type airflow sorter is used to sort the diaphragm.

[0031] The above-mentioned waste lithium-ion battery recycling system also includes an exhaust gas treatment unit;

[0032] The tail gas treatment unit is used to recover or harmlessly treat the gas output by the shredding unit and the drying unit. At the same time, the tail gas treatment unit is also used to treat the exhaust gas of the heating furnace.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. The utility model adopts the method of first shredding, then heating and then hammering, which can make the material be hammered in a dry and fluffy state, so that the black powder falls off, and the degree of dispersion of each material is higher, which is conducive to the later classification and collection of materials.

[0035] At the same time, the shredding unit can effectively reduce the nitrogen consumption of the system due to its unique low speed characteristics.

[0036] 2. In the preferred solution, a first double-shaft shredder and a second double-shaft shredder are arranged up and down, eliminating the need for mechanical material conveying and reducing nitrogen usage. At the same time, compared with a four-shaft shredder, the service life of the blades is significantly increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural diagram of Example 1. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] Example 1

[0040] refer to Figure 1 A waste lithium-ion battery recycling system, characterized by comprising:

[0041] Shredding unit: used to shred waste lithium-ion batteries to obtain shredded products;

[0042] Drying unit 1: heating the shredded product to volatilize the electrolyte, and collecting the volatilized electrolyte and the remaining first solid matter;

[0043] Hammer crushing unit: used for crushing the first solid object to remove the black powder on the first solid object and further crush the first solid object to obtain the first black powder and the second solid object;

[0044] Post-processing subsystem: used to separate the shell, diaphragm, electrode and black powder in the second solid object.

[0045] This embodiment uses a method of sequentially performing shredding, low-temperature heating, and hammer crushing to recycle waste lithium-ion batteries. The rotational speed of the shredding unit is relatively low, not exceeding 50 r / min, and most of the time not exceeding 20 r / min. The low rotational speed of the equipment means that the inert atmosphere is easier to control, thereby requiring less nitrogen to maintain the inert environment.

[0046] After shredding, the drying unit 1 is used to perform low-temperature heating to remove the electrolyte, and the material is kept in a relatively dry state. Then, the material is hammered by the hammer crushing unit, which can greatly increase the proportion of black powder falling off from the material. This large proportion of black powder has a relatively high purity. Since it has not undergone very fine crushing in the early stage, the content of metal debris mixed in it is low.

[0047] Through the above operation, the nitrogen usage can be reduced, the black powder recovery efficiency and purity can be improved, and the difficulty of subsequent material classification and collection can be reduced.

[0048] Preferably, the shredding unit includes a first double-shaft shredder 2 and a second double-shaft shredder 3 ; the material shredding size of the first double-shaft shredder 2 is larger than the material shredding size of the second double-shaft shredder 3 .

[0049] The shredding unit of this embodiment can also be selected from other shredders, such as a four-axis shredder. However, after testing, the blade replacement cycle of the four-axis shredder was found to be 60 days. The short blade replacement cycle is due to the structural characteristics of the four-axis shredder itself. The four-axis shredder consists of two sets of coarse blades and two sets of fine blades. The fine blades must cooperate with both the coarse blades and the adjacent fine blades, resulting in a significantly increased wear rate of the fine blades.

[0050] The design of two double-shaft shredders in this embodiment extends the blade change cycle to 120 days. One of the main reasons for the extended blade change cycle is that each double-shaft shredder is independent and there is no mutual engagement between the four sets of blades, so the blade change cycle is significantly extended.

[0051] In another preferred embodiment of this embodiment, the blades of the first biaxial shredder 2 are 25-50 mm thick, and the blades of the second biaxial shredder 3 are 10-25 mm thick. Based on statistics, for example, a 280Ah prismatic aluminum-cased lithium-ion battery with specifications of 175 mm long, 70 mm wide, and 200 mm high can produce shredded products with a size of approximately 30-150 mm after passing through the first biaxial shredder 2, and approximately 20-50 mm after passing through the second biaxial shredder 3. The shredded products are generally relatively fluffy.

[0052] Preferably, the first biaxial shredder 2, the second biaxial shredder 3, and the drying unit 1 are each independently connected to an inert gas control module; the inert gas control module is used to maintain an inert gas atmosphere in the corresponding first biaxial shredder 2, the second biaxial shredder 3, and the drying unit 1.

[0053] Generally speaking, the oxygen content in the operating atmosphere of the first biaxial shredder 2 and the second biaxial shredder 3 is lower than 5 vol%; the oxygen content in the operating atmosphere of the drying unit 1 is lower than 2 vol%;

[0054] By setting an oxygen sensor inside the corresponding equipment, when it senses that the oxygen content exceeds the set value, the inert gas control module is started to replenish nitrogen to replace the gas in the operating atmosphere, so that the oxygen content of the gas in the operating atmosphere is reduced to below the set value.

[0055] Preferably, the first biaxial shredder 2 , the second biaxial shredder 3 , and the drying unit 1 are arranged in sequence from top to bottom; and a gate valve is provided between the second biaxial shredder 3 and the drying unit 1 .

[0056] The material shredded by the first double-shaft shredder 2 can directly fall into the second double-shaft shredder 3. When the material shredded by the second double-shaft shredder 3 accumulates to a certain level, the gate valve is opened and the material is placed in the drying unit 1 for drying.

[0057] As a preferred embodiment of the present invention, the hammer crushing unit includes a hammer crusher 4 and a first screening machine 5. The hammer crusher 4 is used to crush the first solid matter; the first screening machine 5 is used to screen the material processed by the hammer crusher to obtain a first oversize material and a first undersize material.

[0058] The first oversize material is the second solid material; the first undersize material is the first black powder.

[0059] In this embodiment, preferably, the post-processing subsystem includes an airflow sorting unit, a crusher 6, a second screening machine 7, a grinder 8, a third screening machine 9, and a heating furnace 10;

[0060] The airflow separation unit is used to remove the diaphragm and the shell in the second solid matter to obtain a third solid matter;

[0061] Preferably, the airflow separation unit comprises a plurality of Z-type airflow separators 11 connected in sequence; among the plurality of Z-type airflow separators 11, at least one Z-type airflow separator 11 is used for separating the outer shell, and at least one Z-type airflow separator 11 is used for separating the diaphragm.

[0062] More preferably, the Z-type airflow separator 11 for screening the shell and the Z-type airflow separator 11 for screening the diaphragm can be arranged in no particular order. In this embodiment, the heavier shell is preferably sorted by the front Z-type airflow separator 11, and the lighter diaphragm is preferably sorted by the rear Z-type airflow separator 11. When screening the diaphragm, three-stage series Z-type airflow separators can be used; when screening the shell, only one Z-type airflow separator can be selected.

[0063] The third solid is mainly the electrode, and also contains a small amount of uncleaned shell and diaphragm; there is black powder attached to the electrode;

[0064] The crusher 6 is used to crush the third solid matter to obtain a fourth solid matter;

[0065] The fourth solid material is small metal particles and shell particles after crushing, usually copper and aluminum particles, with a crushed size of 2 to 6 mm; in addition, it also contains black powder and a small amount of diaphragm;

[0066] The second screening machine 7 screens the fourth solid matter to obtain a second oversize material mainly composed of metal particles and a second undersize material mainly composed of black powder;

[0067] Preferably, the second screening machine 7 has a double-layer screen, the double-layer screen is an upper screen and a lower screen, the specification of the upper screen is 5-10 mesh; the specification of the lower screen is 40-120 mesh;

[0068] After being crushed by the crusher 6, the black powder on the electrode is further shed and screened by the second screening machine 7. The double-layer screen of the second screening machine 7 screens out a small amount of diaphragm, hard plastic particles, copper and aluminum particles, and black powder. The final screened material is black powder, and a small amount of diaphragm mixed with it will remain on the upper surface of the upper screen of the double-layer screen; most of the hard plastic particles and copper and aluminum particles remain on the upper surface of the lower screen, and a small amount of hard plastic particles and copper and aluminum particles also remain on the upper surface of the upper screen; whether it is the material on the upper surface of the upper screen or the material on the upper surface of the lower screen, it is collectively referred to as the second screened material;

[0069] The second oversize material is ground using a grinder 8 to obtain a fifth solid material;

[0070] The third screening machine 9 is used to screen the fifth solid matter to obtain a third oversize material and a third undersize material with black powder as the main material;

[0071] Preferably, the third oversize material is processed by a separator, and the separator separates different types of metal particles based on the different specific gravities of the metal particles in the third oversize material; copper particles and aluminum particles are obtained after separation;

[0072] The heating furnace 10 is used to volatilize VOC in at least one of the first black powder, the second undersize material, and the third undersize material; the heating temperature of the heating furnace 10 is lower than the pyrolysis temperature of the binder in the black powder;

[0073] In actual production, the first black powder and the second undersize are processed in a separate heating furnace 10. This portion of black powder is then further de-VOCed in subsequent steps. The third undersize black powder, which contains relatively high levels of metallic impurities, can be processed in a separate facility for cracking and other treatments.

[0074] The heating temperature of heating furnace 10 is 250-320°C. At this temperature, the degree of binder decomposition is low, the production of oligomers is low, the risk of exhaust pipe and dust collector blockage is low, and energy consumption is low. The heating furnace 10 temperature of 250-320°C is lower than the conventional high-temperature pyrolysis method of 400-600°C, and has lower energy consumption. The highest boiling point of the solvent in the electrolyte is less than 250°C. At this temperature, the COD value in the black powder can be reduced to below 1000ppm, meeting the requirements of hydrometallurgy. This temperature is also lower than the thermal decomposition temperature of the adhesive PVDF (around 400°C), resulting in low oligomer production and a low risk of pipe and dust collector blockage.

[0075] During the experiment, we obtained the relationship between the heating temperature of the heating furnace 10 and the COD value in the black powder as follows:

[0076] The COD value of the black powder that has not been treated in the heating furnace 10 is 81270 mg / L; when the temperature of the heating furnace 10 is 200°C, the COD value of the black powder is 7705 mg / L; when the temperature of the heating furnace 10 is 230°C, the COD value of the black powder is 2453 mg / L; when the temperature of the heating furnace 10 is 250°C, the COD value of the black powder is 783 mg / L; when the temperature of the heating furnace 10 is 280°C, the COD value of the black powder is 271 mg / L; when the temperature of the heating furnace 10 is 300°C, the COD value of the black powder is 181 mg / L; when the temperature of the heating furnace 10 is 330°C, the COD value of the black powder is 376 mg / L; when the temperature of the heating furnace 10 is 350°C, the COD value of the black powder is 217 mg / L; it can be seen that when the temperature of the heating furnace 10 is around 300°C, the COD content of the black powder is low and meets the requirements, and there is no need to heat to above 400°C, thereby reducing energy consumption.

[0077] In addition, this embodiment may further include an exhaust gas treatment unit 12;

[0078] The tail gas treatment unit 12 is used to recover or harmlessly treat the gas output by the shredding unit, the drying unit, and the heating furnace.

Claims

1. A waste lithium-ion battery recycling system, characterized in that: include: Shredding unit: used to shred waste lithium-ion batteries to obtain shredded products; Drying unit: heating the shredded product to volatilize the electrolyte, and collecting the volatilized electrolyte and the remaining first solid matter; Hammer crushing unit: used for crushing the first solid object to remove the black powder on the first solid object and further crush the first solid object to obtain the first black powder and the second solid object; Post-processing subsystem: used to separate the shell, diaphragm, electrode and black powder in the second solid object.

2. The waste lithium-ion battery recycling system according to claim 1, characterized in that: The shredding unit includes a first double-shaft shredder and a second double-shaft shredder; the material shredding size of the first double-shaft shredder is larger than the material shredding size of the second double-shaft shredder.

3. The waste lithium-ion battery recycling system according to claim 2, characterized in that: The blade thickness of the first double-shaft shredder is 25 to 50 mm; the blade thickness of the second double-shaft shredder is 10 to 25 mm.

4. The waste lithium-ion battery recycling system according to claim 2, characterized in that: The first biaxial shredder, the second biaxial shredder, and the drying unit are each independently connected to an inert gas control module; the inert gas control module is used to maintain an inert gas atmosphere in the corresponding first biaxial shredder, the second biaxial shredder, and the drying unit.

5. The waste lithium-ion battery recycling system according to claim 2, characterized in that: The first double-shaft shredder, the second double-shaft shredder and the drying unit are arranged in sequence from top to bottom; a gate valve is provided between the second double-shaft shredder and the drying unit.

6. The waste lithium-ion battery recycling system according to claim 2, characterized in that: The hammer crushing unit includes a hammer crusher and a first screening machine, wherein the hammer crusher is used to crush the first solid matter; the first screening machine is used to screen the material processed by the hammer crusher to obtain a first oversize material and a first undersize material; The first oversize material is the second solid material; the first undersize material is the first black powder.

7. The waste lithium-ion battery recycling system according to claim 1, characterized in that: The post-processing subsystem includes an airflow separation unit, a crusher, a second screening machine, a grinder, a third screening machine, and a heating furnace; The airflow separation unit is used to remove the diaphragm and the shell in the second solid matter to obtain a third solid matter; The crusher is used to crush the third solid object to obtain a fourth solid object; The second screening machine screens the fourth solid matter to obtain a second oversize material mainly composed of metal particles and a second undersize material mainly composed of black powder; The grinder is used to grind the second oversize material to obtain a fifth solid material; The third screening machine is used to screen the fifth solid matter to obtain a third oversize material and a third undersize material containing black powder as the main material; The heating furnace is used to volatilize VOC in at least one of the first black powder, the second undersize material, and the third undersize material.

8. The waste lithium-ion battery recycling system according to claim 7, characterized in that: The post-processing subsystem further includes a separator, which separates different types of metal particles based on the different specific gravities of the metal particles in the third oversize material; The second screening machine has a double-layer screen, which includes an upper screen and a lower screen. The specification of the upper screen is 5 to 10 meshes; the specification of the lower screen is 40 to 120 meshes.

9. The waste lithium-ion battery recycling system according to claim 7, characterized in that: The airflow sorting unit includes a plurality of Z-type airflow sorters connected in sequence; among the plurality of Z-type airflow sorters, at least one Z-type airflow sorter is used for sorting the shell, and at least one Z-type airflow sorter is used for sorting the diaphragm.

10. The waste lithium-ion battery recycling system according to any one of claims 1 to 9, characterized in that: Also includes an exhaust gas treatment unit; The tail gas treatment unit is used to recover or harmlessly treat the gas output by the shredding unit and the drying unit.

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