Waste battery discharging equipment and discharging method

Abstract

The invention discloses waste battery discharging equipment and a discharging method. The waste battery discharging equipment comprises a cutting device, a first discharging battery, a crushing device and a second discharging battery, and the cutting device, the first discharging battery, the crushing device and the second discharging battery are sequentially arranged. The waste battery discharging method comprises the following steps: S1, cutting a waste battery to expose electrolyte of the waste battery; s2, discharging the waste battery for the first time by using a first discharging battery; s3, crushing the waste batteries discharged for the first time by using a crusher; and S4, discharging the crushed waste battery for the second time by using a second discharging battery. Compared with the prior art, the method provided by the invention adopts two times of discharging, and for the first time, rapid discharging is performed by exposing and neutralizing electrolyte, so that the electric quantity of the waste battery is rapidly reduced; then crushing the waste battery to expose a battery cell which is not fully discharged in the waste battery, and discharging for the second time; the discharging mode is high in discharging efficiency and thorough in discharging.

Description

Technical Field

[0001] The invention relates to the technical field of waste lithium battery recycling, and in particular to a waste battery discharging device and a discharging method. Background Art

[0002] With the vigorous development of new energy vehicles, the use of various lithium batteries is increasing day by day, and the amount of scrapped lithium batteries is also increasing rapidly. At present, the mainstream processes for lithium battery recycling in China are wet recycling, pyrometallurgical recycling and biological recycling. In order to improve the recycling efficiency, lithium batteries need to be pre-processed, such as discharging, crushing, sorting, etc.

[0003] Used lithium batteries still carry a certain amount of electricity before they are disassembled and crushed. The positive and negative poles of the battery can easily come into contact and cause a short circuit. The short-circuit current will cause the internal temperature of the battery to rise sharply. The crushing behavior will lead to the synthesis and release of heat, toxic and corrosive compounds, and the loss of theoretically recyclable components (such as electrolytes and polymers), leading to combustion or even explosion.

[0004] The existing method of discharging used batteries is generally to place the used batteries in a salt water pool, use the conductive salt water to short-circuit the used batteries, and use the salt water to cool the used batteries to avoid thermal runaway. However, this method has a low discharge efficiency, and often some cells are not discharged to a safe voltage below 1.0 volts. Technicians have found that the cells located in the center of the battery module are not easily exposed to the conductive salt water, and are more likely to be incompletely discharged.

[0005] Moreover, during the crushing process, although the crusher is under inert gas protection, these battery cells with a lot of residual power are still prone to thermal runaway, posing a safety hazard to the crusher, exhaust system and subsequent pyrolysis system. Summary of the invention

[0006] The purpose of the present invention is to overcome the above technical deficiencies and propose a waste battery discharge device and a discharge method to solve the technical problem that the existing waste battery discharge method is difficult to fully discharge all the cells, not only has low discharge efficiency and long discharge time, but also puts forward high requirements on the gas protection of the crusher.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a waste battery discharging device, comprising: a cutting device, the cutting device is used to cut the waste battery to expose the electrolyte of the waste battery; a first discharge cell, the first discharge cell has a first conductive solution, the first conductive solution is alkaline, and is used to neutralize the acidic electrolyte; a crushing device, the crushing device is used to crush the waste battery discharged by the first discharge cell; a second discharge cell, the second discharge cell has a second conductive solution, and is used to completely discharge the waste battery crushed by the crushing device; the cutting device, the first discharge cell, the crushing device and the second discharge cell are arranged in sequence.

[0008] In some embodiments, the first discharge battery includes a water trough and a chain conveyor belt, the water trough is filled with a first conductive solution, the chain conveyor belt extends from the cutting device to the crushing device, and the middle part of the chain conveyor belt is located in the water trough to drive the waste batteries to be immersed in the first conductive solution.

[0009] In some embodiments, it also includes an enclosed hood, an exhaust pump, an exhaust pipe and an exhaust gas treatment tower. The cutting device, the first discharge battery, the crushing device and the second discharge battery are all arranged in the enclosed hood. The exhaust pipe connects the enclosed hood and the exhaust gas treatment tower. The exhaust pump is set on the exhaust pipe to draw the exhaust gas generated in the enclosed hood into the exhaust gas treatment tower for treatment.

[0010] In some embodiments, the crushing device has a nitrogen protection module to provide a nitrogen protection environment when the used batteries are crushed.

[0011] In some embodiments, the water tank is a multi-layer structure, wherein the innermost layer is made of fiberglass.

[0012] In a second aspect, the present invention also provides a method for discharging waste batteries, using waste battery discharging equipment, including the following steps: S1, cutting the waste batteries to expose the electrolyte of the waste batteries; S2, using a first discharge battery to perform a first discharge on the waste batteries; S3, using a crusher to crush the waste batteries that have been discharged for the first time; S4, using a second discharge battery to perform a second discharge on the crushed waste batteries.

[0013] In some embodiments, when the used battery is discharged for the first time in step S2, the pH value of the first conductive solution is maintained greater than 10.

[0014] In some embodiments, a nitrogen protection environment is provided when the waste batteries are crushed in step S3, and the oxygen concentration of the nitrogen protection environment is less than 8%.

[0015] In some embodiments, during the second discharge of the crushed waste batteries in step S4, acid or alkali is added to the second conductive solution to adjust the pH value of the second conductive solution.

[0016] In some embodiments, the first discharge and the second discharge are both 3-6 hours.

[0017] Compared with the prior art, the waste battery discharge method provided by the present invention adopts two discharges. The first discharge is carried out by exposing and neutralizing the electrolyte to quickly discharge and quickly reduce the power of the waste battery; then the waste battery is crushed to expose the internal battery cells that have not been fully discharged, and then the second discharge is carried out; this discharge method not only has high discharge efficiency, but also discharges thoroughly, and it is not easy to have battery cells with a large amount of residual power. At the same time, it can also reduce the gas protection requirements of the crusher and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a waste battery discharge device provided by an embodiment of the present invention; Figure 2 The present invention is a flowchart of a method for discharging a waste battery provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] In order to solve the technical problem that the existing discharge method of waste batteries is difficult to fully discharge all the battery cells, not only the discharge efficiency is low, the discharge takes a long time, but also puts high requirements on the gas protection of the crusher, the present invention provides a waste battery discharge device and a discharge method, which can realize the rapid discharge of waste batteries, not only with high discharge efficiency but also thorough discharge.

[0021] See also Figure 1 , Figure 1 1 is a schematic diagram of the structure of a waste battery discharge device in an embodiment of the present invention, wherein the waste battery discharge device comprises a cutting device 1, a first discharge cell 2, a crushing device 3 and a second discharge cell 4. The cutting device 1, the first discharge cell 2, the crushing device 3 and the second discharge cell 4 are arranged in sequence.

[0022] The cutting device 1 is used to cut the waste battery to expose the electrolyte of the waste battery. It is easy to understand that for the waste battery that is already damaged enough, the cutting device 1 can be skipped and the first discharge battery 2 can be directly discharged. For the intact waste battery or the waste battery with only a small amount of damage, it is necessary to cut it through the cutting device 1 to fully expose the electrolyte.

[0023] The first discharge cell 2 has a first conductive solution, which is alkaline and is used to neutralize the acidic electrolyte. The crushing device 3 is used to crush the waste batteries discharged by the first discharge cell 2. The second discharge cell 4 has a second conductive solution to completely discharge the waste batteries crushed by the crushing device 3.

[0024] In some embodiments, the first discharge cell 2 includes a water tank 21 and a chain plate conveyor belt 22. The water tank 21 is filled with a first conductive solution. The chain plate conveyor belt 22 extends from the cutting device 1 to the crushing device 3. The middle part of the chain plate conveyor belt 22 is located in the water tank 21 to drive the waste batteries to be immersed in the first conductive solution. The continuous conveyor belt 22 drives the waste batteries to move slowly in the water tank 21. The waste conductive solution quickly discharges the waste batteries and absorbs the heat generated by the waste batteries. At the same time, the alkaline first conductive solution also neutralizes the electrolyte and quickly eliminates the electrical energy of the waste batteries. The first discharge solution can be configured with low-concentration salt water and alkali solution. The alkaline first conductive solution also controls the discharge speed. The stronger the alkalinity, the slower the discharge speed, and the weaker the alkalinity, the faster the discharge speed.

[0025] In some embodiments, the water tank 21 is a multi-layer structure, wherein the innermost layer is made of fiberglass reinforced plastics, which has good corrosion resistance and can prevent corrosion and leakage. The outer side is a supporting structure, and a steel plate can be used to support the fiberglass reinforced plastics.

[0026] In some embodiments, the crushing device 3 has a nitrogen protection module to provide a nitrogen protection environment when the waste batteries are crushed to prevent the batteries that are not fully discharged from catching fire.

[0027] In this embodiment, the second discharge cell 4 can adopt the same structure as the first discharge cell 2, except that the second conductive solution is different from the first conductive solution. The second conductive solution uses conductive salt water as a main component, and acid or alkali solution is additionally added to adjust the pH value according to the type of waste batteries.

[0028] In some embodiments, the waste battery discharge equipment further includes a closed cover, an exhaust pump, an exhaust pipe and an exhaust gas treatment tower. The cutting device 1, the first discharge cell 2, the crushing device 3 and the second discharge cell 4 are all arranged in the closed cover, and the closed cover has an inlet for feeding and an outlet for discharging. The exhaust pipe connects the closed cover and the exhaust gas treatment tower, and the exhaust pump is arranged on the exhaust pipe to draw the exhaust gas generated in the closed cover into the exhaust gas treatment tower for treatment. The flue gas generated during the discharge treatment of the waste battery is drawn into the exhaust gas treatment tower by the exhaust pump, and the exhaust gas is treated through alkali washing, acid washing, water washing and other processes to protect the environment and the health of personnel.

[0029] See also Figure 2 The present invention also provides a method for discharging waste batteries, using a waste battery discharging device, comprising the following steps: S1, cutting the waste batteries to expose the electrolyte of the waste batteries. S2, using a first discharge battery 2 to perform a first discharge on the waste batteries. S3, using a crusher 3 to crush the waste batteries that have been discharged for the first time. S4, using a second discharge battery 4 to perform a second discharge on the crushed waste batteries.

[0030] In some embodiments, when the used battery is discharged for the first time in step S2, the neutralization with the acidic electrolyte will continuously consume the alkali solution of the first conductive solution, and the alkali solution needs to be supplemented to keep the pH value of the first conductive solution greater than 10. In other embodiments, the pH value of the first conductive solution can also be adjusted according to the type of battery to obtain a suitable discharge speed.

[0031] In some embodiments, a nitrogen protection environment is provided when the waste batteries are crushed in step S3, and the oxygen concentration of the nitrogen protection environment is less than 8%.

[0032] In some embodiments, when the crushed waste batteries are discharged for the second time in step S4, acid or alkali is added to the second conductive solution to adjust the pH value of the second conductive solution according to the type of the battery.

[0033] In some embodiments, the first discharge and the second discharge are both 3-6 hours.

[0034] In order to better understand the present invention, the following Figure 1 and Figure 2 The technical solution of the present invention is described in detail: When used batteries are damaged by external forces, the insulation performance of the batteries will be reduced, the internal short circuit of the batteries will occur, and thermal runaway will occur. When the battery is in thermal runaway, the electrolyte will decompose the electrolyte interface layer at high temperature, causing the electrolyte to release heat quickly and decompose into high-temperature and flammable gas. This used battery discharge device uses the principle of thermal runaway to quickly discharge used batteries.

[0035] First, the waste battery is cut with a cutting device 1 to expose the electrolyte of the waste battery. At this time, a short circuit occurs inside the waste battery, and the electrical energy is quickly converted into heat energy and accumulated. If not treated, the waste battery will catch fire in a short time and produce a large amount of smoke and other substances. In order to avoid this situation, after the cutting device 1 cuts the waste battery, the waste battery is immediately placed in the first discharge battery 2. It should be noted that in step S1, it is not necessary to cut all the cells in the battery, but only a part of it is cut to expose the electrolyte of the part of the cell.

[0036] The first conductive solution in the first discharge battery 2 can absorb the heat generated by the waste battery to avoid violent fire and combustion. At the same time, the alkaline first conductive solution can also neutralize the acidic electrolyte and quickly eliminate the electric energy of the battery cell. The first conductive solution can also act as a conductor to conduct the uncut battery cell and discharge it. This method of neutralizing the electrolyte of the battery cell can quickly eliminate the electric energy in the battery cell and significantly reduce the electric quantity of each battery cell in the battery in a relatively short time.

[0037] After the waste battery is discharged by the first discharge cell 2, some cells are still not fully discharged and the residual power is high. These cells are generally located in the center of the battery module and are not in good contact with the first conductive solution. Therefore, the waste battery is completely crushed by the crushing device 3 to completely expose the internal cells. When the crushing device 3 is crushing, nitrogen protection is used. Due to the large-scale discharge of the first discharge cell 2, the requirements for nitrogen protection can be greatly reduced compared with the existing method, and the oxygen concentration only needs to be less than 8%.

[0038] After being crushed by the crushing device 3, the battery enters the second discharge battery 4 for the second discharge, so as to completely discharge the battery cells with high residual power, so that the power of each battery cell is reduced to below the safety line. Then, the battery is conveyed to the subsequent low-temperature drying process by the chain conveyor.

[0039] The waste battery discharge method provided by the present invention adopts two discharges. The first discharge is carried out by exposing and neutralizing the electrolyte to quickly discharge and quickly reduce the power of the waste battery; then the waste battery is crushed to expose the internal battery cells that are not fully discharged, and then the second discharge is carried out; this discharge method not only has high discharge efficiency, but also discharges thoroughly, and it is not easy to have a battery cell with a large amount of residual power, and at the same time, it can reduce the gas protection requirements of the crusher and reduce costs.

[0040] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A waste battery discharge device, characterized in that: include: A cutting device, the cutting device is used to cut the waste battery to expose the electrolyte of the waste battery; a first discharge cell, the first discharge cell having a first conductive solution, the first conductive solution being alkaline to neutralize an acidic electrolyte; A crushing device, the crushing device is used to crush the waste batteries discharged by the first discharge cell; a second discharge battery, wherein the second discharge battery has a second conductive solution to completely discharge the waste batteries after being crushed by the crushing device; The cutting device, the first discharge cell, the crushing device and the second discharge cell are arranged in sequence.

2. The waste battery discharge device according to claim 1, characterized in that: The first discharge battery includes a water trough and a chain conveyor belt, the water trough is filled with the first conductive solution, the chain conveyor belt extends from the cutting device to the crushing device, and the middle part of the chain conveyor belt is located in the water trough to drive the waste battery to be immersed in the first conductive solution.

3. The waste battery discharge device according to claim 1, characterized in that: It also includes a closed cover, an exhaust pump, an exhaust pipe and an exhaust gas treatment tower. The cutting device, the first discharge cell, the crushing device and the second discharge cell are all arranged in the closed cover. The exhaust pipe connects the closed cover and the exhaust gas treatment tower. The exhaust pump is arranged on the exhaust pipe to draw the exhaust gas generated in the closed cover into the exhaust gas treatment tower for treatment.

4. The waste battery discharge device according to claim 1, characterized in that: The crushing device has a nitrogen protection module to provide a nitrogen protection environment when the waste batteries are crushed.

5. The waste battery discharge device according to claim 2, characterized in that: The water tank is a multi-layer structure, wherein the innermost layer is made of fiberglass.

6. A method for discharging waste batteries, characterized in that: Using the waste battery discharge device as described in any one of claims 1 to 5 comprises the following steps: S1. Cutting the waste battery to expose the electrolyte of the waste battery; S2, using the first discharge battery to discharge the used battery for the first time; S3, using the crusher to crush the waste batteries that have been discharged for the first time; S4, using the second discharge battery to discharge the crushed waste battery for the second time.

7. The method for discharging waste batteries according to claim 6, characterized in that: When discharging the used battery for the first time in step S2, the pH value of the first conductive solution is maintained to be greater than 10.

8. The method for discharging waste batteries according to claim 6, characterized in that: In step S3, a nitrogen protection environment is provided when the waste batteries are crushed, and the oxygen concentration of the nitrogen protection environment is lower than 8%.

9. The method for discharging waste batteries according to claim 6, characterized in that: When the crushed waste batteries are discharged for the second time in step S4, acid or alkali is added to the second conductive solution to adjust the pH value of the second conductive solution.

10. The method for discharging waste batteries according to claim 6, characterized in that: The time of the first discharge and the second discharge are both 3-6 hours.

Images