Discharge method for preventing internal electrolyte leakage of cylindrical waste battery

Abstract

The application provides a discharge method for preventing internal electrolyte leakage of a cylindrical waste battery, comprising the following steps: (1) heating a wrapping material to obtain a liquid-phase wrapping material; (2) coating the liquid wrapping material on the connection between a metal sheet at a positive electrode tab of the cylindrical waste battery and a battery shell and the connection between a metal sheet at a negative electrode tab and the battery shell, and standing and cooling; (3) immersing the waste battery coated with the wrapping material into a discharge solution for discharging, taking out the waste battery, drying the surface of the waste battery, testing the discharge voltage, confirming complete discharge of the waste battery, removing the wrapping material on the waste battery, and screening and recycling the waste battery. The discharge method fully utilizes the excellent properties of the wrapping material such as paraffin, effectively prevents the pollution of the discharge solution caused by the electrolyte leakage during the discharging process, and reduces the subsequent pollution control.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery recycling, and in particular to a discharging method for preventing internal electrolyte leakage of a cylindrical waste battery. BACKGROUND

[0002] With the improvement of the social technology level and people's living standards, electronic products have become an indispensable part of people's lives, and the most common energy storage device is a portable cylindrical battery. Although the cylindrical battery brings convenience to people's life, the large amount of toxic electrolyte and positive and negative electrode metals contained in the battery will cause irreversible effects on the bodies of various organisms if they flow into the soil and water. Therefore, how to reasonably and effectively treat and recycle waste batteries is an important problem currently faced by society.

[0003] Battery discharging is an indispensable part of the resource utilization process of waste batteries, and a battery that is not completely discharged is extremely prone to cause serious production accidents during disassembly. At present, the discharging method of waste batteries is usually to directly immerse the waste battery in a salt solution for discharging. However, the discharging solution is prone to corrode the positive and negative electrodes during the discharging process, causing the loss of electrolyte. If the electrolyte seeps out and is not handled properly, it will have a serious impact on the environment, and is also not conducive to the storage of the subsequent electrolyte. SUMMARY

[0004] In order to solve the above-mentioned problems, the purpose of the present application is to provide a waste battery discharging method that can effectively prevent the pollution of the discharging solution caused by the seepage of electrolyte during the discharging process, and reduce the subsequent pollution control.

[0005] In order to achieve the purpose of the present application, the present application adopts the following technical solution:

[0006] The present application provides a discharging method for preventing internal electrolyte leakage of a cylindrical waste battery, comprising:

[0007] (1) heating a wrapping material to obtain a liquid phase wrapping material;

[0008] (2) coating the liquid wrapping material at the connection between the metal sheet at the positive tab of the cylindrical waste battery and the battery shell and the connection between the metal sheet at the negative tab and the battery shell, and standing for cooling;

[0009] (3) immersing the waste battery coated with the wrapping material in a discharging solution for discharging, taking out the waste battery and drying its surface, then testing the discharging voltage, confirming that the waste battery is completely discharged, removing the wrapping material on the waste battery, and screening and recycling the waste battery.

[0010] In some embodiments, the wrapping material in step (1) is selected from natural paraffin, polyethylene or polypropylene;

[0011] The natural paraffin is preferred.

[0012] In some embodiments, the temperature for heating the coating material is controlled at 70-150°C.

[0013] The water bath heating method is preferred.

[0014] In some embodiments, in step (2), the waste battery is selected from the retired batteries with no obvious damage in appearance.

[0015] In some embodiments, the coating thickness of the liquid coating material is not less than 2mm, and is preferably 0.3-0.5cm.

[0016] In some embodiments, in step (2), the liquid coating material is cooled to 20-30°C by air cooling or natural cooling.

[0017] Preferably, the air speed during the cooling process is controlled at 0.5-4m / s.

[0018] In some embodiments, in step (3), the waste battery coated with the coating material is soaked at a discharge temperature of 20-40°C for not less than 60min.

[0019] In some embodiments, the discharge solution is selected from a salt solution, and is preferably a sodium chloride aqueous solution.

[0020] In some embodiments, the surface of the removed waste battery is dried by wiping or hot air drying.

[0021] Preferably, the temperature for the hot air drying is 80-120°C, and the time is 30-40min.

[0022] In some embodiments, the coating material on the waste battery is removed by heating.

[0023] Preferably, the heating temperature is above 70°C.

[0024] The technical solution provided by the present application has the following beneficial effects:

[0025] The discharge method provided by the present application fully utilizes the excellent properties of the coating material such as paraffin by coating the coating material at the connection between the metal sheet and the battery shell at the tab, effectively prevents the pollution of the discharge solution by the electrolyte leakage during the discharge process on the basis of ensuring the full discharge of the waste battery, and also reduces the subsequent pollution control. DETAILED DESCRIPTION

[0026] The specific embodiments of the present application are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The term "and / or" as used herein refers to and encompasses any and all combinations of one or more of the associated listed items.

[0028] The present application provides a method for preventing internal electrolyte leakage of cylindrical waste batteries, comprising:

[0029] (1) heating the wrapping material to obtain liquid phase wrapping material;

[0030] (2) coating the liquid wrapping material at the connection between the metal sheet at the positive tab of the cylindrical waste battery and the battery shell and the connection between the metal sheet at the negative tab and the battery shell, and standing for cooling;

[0031] (3) soaking the waste battery coated with the wrapping material in a discharging solution for discharging, taking out the waste battery and drying the surface of the waste battery, then testing the discharging voltage, confirming that the waste battery is completely discharged, removing the wrapping material on the waste battery, and screening and recycling the waste battery.

[0032] The wrapping material selected in step (1) of the method of the present application can be natural paraffin, polyethylene or polypropylene; paraffin and other materials have the advantages of low melting point, insulation, stable chemical properties, low price, etc., and can be used as the coating material at the connection between the metal at the tab of the waste battery and the shell, and the paraffin and other materials can be used to precisely isolate the connection between the positive and negative tabs and the contact with the discharging salt solution, so that the electrolyte in the waste battery does not flow out during discharging.

[0033] In some specific embodiments, the solid wrapping material paraffin is placed in a beaker, heated to liquid paraffin in a water bath, and the paraffin is evenly coated on the connection between the metal sheet at the positive tab of the battery and the battery shell and the connection between the metal sheet at the negative tab and the battery shell using a rubber bulb dropper, and the paraffin is allowed to cool and solidify after standing for a period of time.

[0034] In some preferred embodiments, the wrapping material is natural paraffin.

[0035] In the method of the present application, the temperature for heating the wrapping material is controlled at 70-150℃; preferably, the water bath heating method can be used to heat the wrapping material.

[0036] In step (2) of the method of the present application, the waste battery is selected from the retired cylindrical battery whose service life has ended and whose appearance has no obvious damage, and the waste battery in the present application includes but is not limited to 18650 type battery.

[0037] In some specific embodiments, the thickness of the liquid coating material applied at the connection between the metal sheet of the tab and the battery shell is not less than 2 mm; preferably, the thickness of the coating is between 0.3-0.5 cm, such as 0.3 cm, 0.4 cm.

[0038] In step (2) of the method of the present application, the liquid coating material is cooled to between 20-30℃ by air cooling to solidify the coating material at the connection between the metal sheet of the tab and the battery shell; preferably, the air cooling speed is controlled to be between 0.5-4 m / s, such as 1 m / s, 2 m / s, 3 m / s.

[0039] In step (3) of the method of the present application, the waste battery coated with the coating material is immersed in a discharging solution for discharging, specifically, the temperature of the battery immersion is between 20-40℃, such as 25℃, 30℃, 35℃; the discharging time is not less than 60 min, preferably between 90-120 min, such as 100 min, 110 min.

[0040] In some specific embodiments, the discharging solution in the method of the present application is selected from a salt solution, such as an aqueous sodium chloride solution, an aqueous potassium chloride solution; preferably, the aqueous sodium chloride solution, and the specific concentration can be selected between 4-8 mol / L.

[0041] In the discharging method of the present application, after the discharging is completed, the waste battery is taken out of the discharging solution, and the residual discharging solution on the surface of the waste battery is wiped or dried by hot air drying, preferably by hot air drying; specifically, the temperature of the hot air drying is between 80-120℃, such as 90℃, 100℃, 110℃, and the time is between 30-40 min, such as 35 min.

[0042] In some specific embodiments, the voltmeter is used to measure the residual voltage of each waste battery, and the voltage of the waste battery is measured at least three times, the voltmeter readings are recorded, and the average value of the readings is taken; when the residual voltage is between 0-0.1 V, it is considered that the battery is completely discharged.

[0043] The discharging method of the present application uses heating to remove the coating material coated on the waste battery, specifically, the coating material can be melted by heating to be removed, and the melted coating material can be reused; more specifically, the heating temperature can be above 70℃, preferably between 70-100℃, such as 80℃, 85℃, 90℃.

[0044] The present application will be further described in the following specific examples, but should not be understood as being limited to the present application.

[0045] The specific experimental steps or conditions not indicated in the examples can be operated according to the corresponding conventional experimental steps or conditions in the technical field. The reagents used are not indicated by the manufacturer, and are conventional reagents available in the field.

[0046] The following examples were tested for the content of fluoride ions (F - ) in the discharged solution by the following method: Inductively coupled plasma mass spectrometry (ICP-MS) is a commonly used technique for detecting the content of fluoride ions in water bodies.

[0047] Example 1

[0048] (1) The paraffin was melted into a liquid under the condition of heating at 80°C in a water bath;

[0049] (2) The used Nanfu waste batteries were selected, and 0.4 cm of liquid paraffin was uniformly coated on the metal sheet at the positive electrode lug of the battery and the connection between the battery shell and the metal sheet at the negative electrode lug by using a rubber bulb dropper. The wind speed was controlled at 1.5 m / s for air cooling until the paraffin solidified.

[0050] (3) The waste battery coated with paraffin (battery voltage 1.02 V) was immersed in 200 mL of 6 mol / L potassium chloride aqueous solution for discharge, and the discharge reaction was carried out at room temperature for 48 h. After the discharge was completed, the waste battery was taken out and the surface was dried with hot air at 80°C, and the voltage after discharge was 0 V.

[0051] The paraffin material on the above waste battery was removed, and the waste battery was screened and recovered.

[0052] Example 2

[0053] (1) The paraffin was melted into a liquid under the condition of heating at 85°C in a water bath;

[0054] (2) The used Nanfu waste batteries were selected, and 0.4 cm of liquid paraffin was uniformly coated on the metal sheet at the positive electrode lug of the battery and the connection between the battery shell and the metal sheet at the negative electrode lug by using a rubber bulb dropper. The wind speed was controlled at 1.5 m / s for air cooling until the paraffin solidified.

[0055] (3) The waste battery coated with paraffin (battery voltage 1.21 V) was immersed in 200 mL of 4 mol / L sodium chloride aqueous solution for discharge, and the discharge reaction was carried out at room temperature for 40 h. After the discharge was completed, the waste battery was taken out and the surface was dried with hot air at 80°C, and the voltage after discharge was 0 V.

[0056] The paraffin material on the above waste battery was removed, and the waste battery was screened and recovered.

[0057] Example 3

[0058] (1) Under the condition of 80℃ water bath heating, paraffin is melted into liquid;

[0059] (2) Select the cylindrical waste battery disassembled from the used electric vehicle, evenly coat 0.4 cm of liquid paraffin on the connection between the metal sheet at the positive electrode tab of the battery and the battery shell and the metal sheet at the negative electrode tab and the battery shell using a rubber head dropper, and cool to paraffin solidification by controlling the air speed to 1.5 m / s air cooling mode;

[0060] (3) The waste battery coated with paraffin (battery voltage 0.72V) is immersed in 200mL, 6mol / L sodium chloride aqueous solution for discharge, and the discharge reaction is carried out at room temperature for 30h. After the discharge is completed, the waste battery is taken out and the surface is dried by hot air at 80℃, and the voltage after discharge is tested to be 0.1V.

[0061] The paraffin material on the above waste battery is removed and the waste battery is screened and recovered.

[0062] Example 4

[0063] (1) Under the condition of 100℃ water bath heating, polyethylene is melted into liquid;

[0064] (2) Select the used Nanshifu waste battery, evenly coat 0.4 cm of liquid polyethylene on the connection between the metal sheet at the positive electrode tab of the battery and the battery shell and the metal sheet at the negative electrode tab and the battery shell using a rubber head dropper, and cool to polyethylene surface solidification by controlling the air speed to 1.5 m / s air cooling mode;

[0065] (3) The waste battery coated with polyethylene (battery voltage 0.75V) is immersed in 200mL, 4mol / L sodium chloride aqueous solution for discharge, and the discharge reaction is carried out at room temperature for 40h. After the discharge is completed, the waste battery is taken out and the surface is dried by hot air at 80℃, and the voltage after discharge is tested to be 0.1V.

[0066] The polyethylene material on the above waste battery is removed and the waste battery is screened and recovered.

[0067] Example 5

[0068] (1) Under the condition of 160℃ heating, polypropylene is melted into liquid;

[0069] (2) Select the used Nanshifu waste battery, evenly coat 0.4 cm of liquid polypropylene on the connection between the metal sheet at the positive electrode tab of the battery and the battery shell and the metal sheet at the negative electrode tab and the battery shell using a rubber head dropper, and cool to polypropylene solidification by controlling the air speed to 1.5 m / s air cooling mode;

[0070] (3) The polypropylene-coated waste battery (battery voltage 1.15V) was immersed in 200 mL of 4 mol / L sodium chloride aqueous solution for discharging, and the discharging reaction was carried out at room temperature for 40 h. After discharging, the waste battery was taken out and the surface was dried with hot air at 80°C, and the voltage after discharging was 0.1V.

[0071] The polypropylene material on the above waste battery was removed, and the waste battery was screened and recovered.

[0072] Comparative Example 1

[0073] The discharging was carried out according to the method of Reference Example 2, except that the metal sheet at the connection between the tab and the battery shell was not coated with paraffin wax, and the voltage of the waste battery before discharging was 0.98V.

[0074] Comparative Example 2

[0075] The discharging was carried out according to the method of Reference Example 2, except that the discharging solution was water, and the voltage of the waste battery before discharging was 1.21V, and the voltage of the battery after discharging was 1.21V.

[0076] Comparative Example 3

[0077] The discharging was carried out according to the method of Reference Example 2, except that in step (2), the entire outer wall of the waste battery was coated with liquid paraffin wax, and the voltage of the waste battery before discharging was 0.73V, and the voltage of the waste battery after discharging was 0.73V.

[0078] Comparative Example 4

[0079] (1) The paraffin wax was melted into a liquid under the condition of heating at 85°C water bath;

[0080] (2) The used Nanfu waste battery was selected, and 0.4 cm of liquid paraffin wax was uniformly coated on the connection between the metal sheet at the positive tab and the battery shell and the metal sheet at the negative tab and the battery shell using a rubber bulb dropper. The cooling method was controlled to be air cooling at a wind speed of 1.5 m / s until the paraffin wax solidified.

[0081] (3) The paraffin wax-coated waste battery (battery voltage 0.58V) was immersed in 200 mL of 4 mol / L sodium chloride aqueous solution for discharging, and the discharging reaction was carried out at a temperature of 60°C for 40 h. After discharging, the waste battery was taken out and the surface was dried with hot air at 80°C, and the voltage after discharging was 0V.

[0082] The paraffin wax material on the above waste battery was removed, and the waste battery was screened and recovered.

[0083] The discharging solution in the above example was detected, and the test results were as follows:

[0084]

[0085] As can be seen from the data in the above table, the discharge method provided by the present application can effectively prevent the pollution of the discharge solution caused by the leakage of electrolyte during the discharge process while ensuring complete discharge of the waste battery, and minimizes the subsequent pollution control.

Claims

1. A discharge method for preventing internal electrolyte leakage from a cylindrical spent battery, characterized by, The method comprises: (1) heating a wrapping material to obtain a liquid phase of the wrapping material; (2) coating the liquid wrapping material at the connection between the metal sheet at the positive electrode tab of the cylindrical waste battery and the battery shell and the connection between the metal sheet at the negative electrode tab and the battery shell, and standing for cooling; (3) soaking the waste battery coated with the wrapping material in a discharging solution for discharging, taking out the waste battery and drying the surface of the waste battery, then testing the discharging voltage, confirming that the waste battery is completely discharged, removing the wrapping material on the waste battery, and screening and recycling the waste battery; The wrapping material in step (1) is selected from natural paraffin, polyethylene or polypropylene.

2. The discharge method according to claim 1, characterized by, The wrapping material in step (1) is selected from natural paraffin.

3. The electrical discharge method of claim 2, wherein, The temperature for heating the wrapping material is controlled at 70-150℃.

4. The electrical discharge method of claim 3, wherein, The wrapping material is heated by a water bath heating method.

5. The electrical discharge method according to any one of claims 1 to 4, characterized in that, In step (2), the waste battery is selected from a retired battery with an end of service life and no obvious damage in appearance.

6. The electrical discharge method of claim 5, wherein, The coating thickness of the liquid wrapping material is not less than 2 mm.

7. The electrical discharge method of claim 6, wherein, The coating thickness of the liquid wrapping material is 0.3-0.5 cm.

8. The electrical discharge method of claim 6, wherein, In step (2), the liquid wrapping material is cooled to 20-30℃ by air cooling.

9. The electrical discharge method of claim 8, wherein, The air speed during cooling is controlled at 0.5-4 m / s.

10. The electrical discharge method according to any one of claims 1 to 4, 6 to 9, characterized in that, In step (3), the waste battery coated with the wrapping material is soaked at a discharging temperature of 20-40℃ for not less than 60 min.

11. The electrical discharge method of claim 10, wherein, The discharging solution is selected from a salt solution.

12. The electrical discharge method of claim 11, wherein, The discharging solution is selected from a sodium chloride aqueous solution.

13. The electrical discharge method of claim 11, wherein, The surface of the taken-out waste battery is dried by wiping or hot air drying.

14. The electrical discharge method of claim 13, wherein, The temperature for hot air drying is 80-120℃, and the time is 30-40 min.

15. The electrical discharge method of claim 13, wherein, The wrapping material on the waste battery is removed by heating.

16. The electrical discharge method of claim 15, wherein, The heating temperature is above 70℃.

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