Method for recycling battery materials

Abstract

Method For Recycling Battery Materials A method for recycling battery materials comprises soaking negative current collectors in a first solution for a predetermined soaking time period to obtain separated copper foils and graphite powders, extracting the copper foil from the first solution; drying the copper foil; cleaning the copper foil; extracting the graphite powders from the first solution and drying the graphite powder. The soaking step causes an adhesive between a graphite coating and a copper foil to be dissolved in the first solution such that the graphite coating is separated from the copper foil and to cause the graphite coating to be dispersed into the first solution to form graphite powders. A method according to the present invention enables copper material and graphite material recycling from batteries without cutting or shredding the batteries into fragments and achieves battery materials recycling with high efficiency.

Description

[0001] Method For Recycling Battery Materials

[0002] The present application claims priority to Singapore patent application number 10202400086T filed on 10 January' 2024 and Singapore patent application number 10202401495R filed on 27 May 2024. Hie full content of which are hereby incorporated by reference as if set forth in its entirety herein.

[0003] Technical Field

[0004] The present application relates to battery' recycling technology. In particular, the present application relates to a method for recycling materials from negative current collectors of batteries.

[0005] Background

[0006] Batteries such as lithium batteries have becoming one of the most widely used mobile energy' sources in many industrial and daily life applications. With the usage of batteries greatly increasing, aged and discarded batteries have become a major issue of environmental concern and sustainability of social developments. Industrial players have been endeavoured with continuous efforts in developing effective and practical solutions for battery recycling for the purposes of possible environmental pollutions reduction and better reusage of the precise metals and other materials from the recycled battery' parts.

[0007] Present battery recycling technologies mainly focus on active ingredients recycling and less solution is available for recycling of inactive materials such as copper material and graphite powders from the negative current collectors of batteries. Some known negative current collectors recycling involves complicated and high cost processes of pulverization of both the positive and negative current collectors, for the purposes of obtaining the aluminium and copper materials and by refinery processes. The aluminium material of the positive current collectors is itself consumed as the reducing agent during the refinery' and further, the copper material is mixed with other elements such as nickel and cobalt etc, which require further metallurgical processes of purification before the copper material can be obtained. Such recycling methods also result in high energy consumption, high level of matenal wastes and secondary pollution.

[0008] It is therefore desirable to provide an improved material recycling method to solve at least one of the problems identified above.

[0009] Summary

[0010] According to one aspect, the present invention provides a method for recycling negative current collectors from batteries. In one embodiment, the method comprises extracting cells from batteries, separating negative current collectors from positive current collectors of the cell, soaking the negative current collector in a first solution for a predetermined time period to separate a graphite coating from a copper foil, drying the copper foil, and cleaning the copper foil to remove attachments from the copper foil.

[0011] Preferably, the first solution comprises a 3% to 8%wt hydrochloric acid.

[0012] Preferably, the predetermined time period is 2 minutes to 5 minutes.

[0013] Preferably, the method further comprises subjecting the first solution to a first ultrasonic oscillation, during soaking the negative current collector in the first solution, to separate the graphite coating from the copper foil.

[0014] Preferably, the first ultrasonic oscillation has a power of 600 watts to 1500 watts and a frequency of 30 KHz to 50KHz.

[0015] Preferably, the method further comprises, after socking the negative current collector in the first solution and prior to drying the copper foil, cleaning the copper foil in a second solution to remove residues of the first solution.

[0016] Preferably, the method further comprises subjecting the second solution to a second ultrasonic oscillation during cleaning the copper foil to remove residues of the first solution. Preferably, the second solution is water and the second ultrasonic oscillation has a power of 300 watts to 1500 watts and a frequency 20 KHz to35KHz.

[0017] Preferably, the step of drying the copper foil is implemented under a temperature not exceeding 60 degrees Celsius.

[0018] Preferably, the step of cleaning the copper foil to remove attachments from the copper foil comprises cleaning the copper foil to remove oxides, adhesive particles and carbon powders from the copper foil.

[0019] Preferably, cleaning the copper foil comprises laser ablating the copper foil to remove the oxides, adhesive particles and carbon powers.

[0020] Preferably, the laser ablating is implemented under a cleaning speed of 0.3 - 0.5 second per square centimeter on a surface of the copper foil.

[0021] Preferably, the laser ablating forms a surface texture on tire copper foil, wherein the surface texture compnses grooves and ridges with a pitch of 10 micrometers.

[0022] Preferably, the laser ablating is implemented by a MOPA (Master Oscillator Power Amplifier) laser.

[0023] According to another aspect, the present invention provides a method for recycling battery materials. In one embodiment, the method comprises a step of soaking battery negative current collectors in a first solution for a predetermined soaking time period, a step of extracting the copper foil of the negative current collectors from the first solution, a step of drying the copper foil and a step of cleaning the copper foil. During the step of soaking the negative current collectors, the adhesive between the copper foil and the graphite coatings on the copper foil is dissolved in the first solution, by which, the graphite coatings are detached and separated from the copper foil and further, the graphite coatings are dispersed into the first solution to form graphite powders. During the step of extracting the copper foil from the first solution, concurrently and / or sequentially, the method 200 further includes a step 260 of extracting the graphite powders from the first solution, and a step 270 of drying the graphite power.

[0024] With the solutions provided by the present application, the present invention enables negative current collectors recycling by effectively obtaining the copper material and graphite material from the negative current collector of batteries. A method according to the present invention enables copper material and graphite material recycling without cutting or shredding the batteries into fragments and achieves copper material recycling with high efficiency.

[0025] Brief Description of Drawings

[0026] The technical solutions and corresponding technical features of the embodiments will be more comprehensively understood in conjunction with the accompanying drawings, in which:

[0027] Fig. 1 is a flow chart showing a method for recycling battery materials according to one embodiment of the present invention:

[0028] Fig. 2 is a flow chart showing an exemplary detailed step of the method shown in Fig. 1;

[0029] Fig. 3 is a flow chart showing an exemplary additional step of the method shown in Fig. 1;

[0030] Fig. 4 is a flow chart showing an exemplary detailed step of the method shown in Fig. 1;

[0031] Fig. 5 is a flow chart showing an exemplary further step of the method shown in Fig. 1;

[0032] Fig. 6 is a flow chart showing an exemplary further step of the method shown in Fig. 5.

[0033] Fig. 7 is a flow chart showing a method for recycling battery materials according to one embodiment of the present invention;

[0034] Fig. 8 is a flow chart showing an exemplary detailed step of the method shown in Fig. 7; Fig. 9 is a flow chart showing an exemplary detailed step of tire method shown in

[0035] Fig. 7;

[0036] Fig. 10 is a flow chart showing an exemplary detailed step of the method shown in Fig. 7;

[0037] Fig. 11 is a flow chart showing an exemplary detailed step of the method shown in Fig. 7.

[0038] Detailed Description

[0039] As shown in Fig. 1, according to one embodiment of the present invention, a method 100 for recycling battery materials from negative current collectors comprises, a step 120 of retracting a cell from a housing of a battery', a step 130 of separating negative current collectors from positive current collectors of the cell, a step 140 of soaking the negative current collector in a first solution for a predetennined time period, to separate a graphite coating from a copper foil, a step 160 of drying the copper foil and a step 170 of cleaning the copper foil to remove attachments from the copper foil.

[0040] Preferably, the first solution comprises a 3% to 8 %wt hydrochloric acid, and tire predetermined time period is 2 minutes to 5 minutes. As shown in Fig. 2, during the step 140 of soaking the negative current collector in a first solution for a predetennined time period to separate a graphite coating from a copper foil, the method 100 may include a step 142 of subject the first solution to a first ultrasonic oscillation e.g. an ultrasonic oscillation having a power of 600 watts to 1500 watts and a frequency of 30 KHz to 50KHz.

[0041] Preferably, as shown in Fig. 3 and with reference to Fig. 1, after the step 140 of socking the negative current collector in the first solution and prior to the step 160 of drying the copper foil, the method 100 may further include a step 150 of cleaning the copper foil in a second solution, to remove residues of the first solution.

[0042] Preferably, ss shown in Fig. 4, the step 150 of cleaning the copper foil in a second solution to remove residues of the first solution may further comprise a step 152 of subjecting the water to a second ultrasonic oscillation during cleaning the copper foil, to remove residues of the first solution. Preferably, the second solution is water, and tire second ultrasonic oscillation has a power of 300 watts to 1500 watts and a frequency of 20 KHz to 35KHz. Preferably the step 160 of drying the copper foil is implemented under a temperature not exceeding 60 degrees Celsius.

[0043] Preferably, as shown in Fig. 5, the step 170 of cleaning the copper foil to remove attachments from the copper foil comprises a step 172 of cleaning the copper foil to remove oxides, adhesive particles and carbon powders from the copper foil. More preferably, as shown in Fig. 6, the step 172 of cleaning oxides, adhesive particles and carbon powders from the copper foil comprises a step 174 of laser ablating the copper foil to remove the oxides, adhesive particles and carbon powers.

[0044] Preferably, the laser may be a MOPA laser, and laser ablating the copper foil is implemented under a cleaning speed of 0.3 to 0.5 second per square centimeter on a surface of the copper foil. The laser ablating forms a surface texture on the copper foil upon completion of the laser ablation, and the surface texture comprises grooves and ridges with a pitch of 10 micrometers between the grooves and ridges.

[0045] As shown in Fig. 7, according to another embodiment of the present invention, a method 200 for recycling battery materials comprises, a step 220 of soaking battery' negative current collectors in a first solution for a predetermined soaking time period, a step 230 of extracting the copper foil of the negative current collectors from the first solution, a step 240 of drying the copper foil and a step 250 of cleaning the copper foil, such that the copper material is recycled from the negative current collectors.

[0046] Negative current collectors may be obtained from used and / or discarded batteries upon the batteries being fully discharged and disassembled, by separating the negative current collectors from the battery housing.

[0047] During the step 220 of soaking the negative current collectors, the adhesive betw een the copper foil and the graphite coatings on the copper foil is dissolved in the first solution, by which, the graphite coatings are detached and separated from the copper foil and further, the graphite coatings are dispersed into the first solution to form graphite powders.

[0048] Dunng the step 230 of extracting the copper foil from the first solution, concurrently and / or sequentially, the method 200 further includes a step 260 of extracting the graphite powders from the first solution, and a step 270 of drying the graphite power, such that the graphite material is recycled from the negative current collectors.

[0049] The first solution may comprise NMP (N-Methyl-2-Pyrrolidone), and the NMP has a temperature between 70 degrees Celsius to 90 degrees Celsius during soaking the negative current collectors, and the step 220 of soaking the negative current collectors is implemented for a predetermined soaking time period of 40 minutes to 60 minutes.

[0050] Preferably, the NMP has a temperature between 75 degrees Celsius to 85 degrees Celsius during soaking the negative current collectors, and the predetermined soaking time period is 45 minutes to 55 minutes, which results in better reduction of the strength and degradation of the adhesive by the NMP, and dissolution of the adhesive into the NMP.

[0051] Preferably, as shown in Fig. 8, during the step 200 of soaking the negative current collectors, the method 200 further comprises a step 222 of subjecting the first solution to an ultrasonic oscillation for a predetermined processing time, to improve the effect of detachment and separation of the graphite coating from the copper foil. Preferably, the ultrasonic oscillation has a power of 300 watts to 800 watts and a frequency of 30 KHz to 50KHz frequency, and the predetermined processing time is 5 to 15 minutes. More preferably, the ultrasonic oscillation has a power of 400 watts to 600 watts and a frequency of 35 KHz to 45KHz frequency, and the predetermined processing time is 7 to 12 minutes, which results in improved separation effect of the graphite coatings from the copper foils.

[0052] Preferably, the step 240 of drying the copper foil is implemented in a step 242 under a baking temperature of 200 degrees Celsius to 230 degrees Celsius, and under a slight negative pressure of e.g. -10 Pa to -30 Pa, to remove residues of the NMP from the copper foils. More preferably, the negative pressure is in a range of -10 Pa to -25 Pa, and the baking temperature is in a range of 210 degrees Celsius to 230 degrees Celsius.

[0053] Preferably, the step 250 of cleaning the copper foil comprises a step 252 of laserablating the copper foil to clean the surface of the copper foil. The laser-ablating the copper foil maybe implemented by a MOPA laser and under a laser beam scanning speed of 0.3 to 0.5 second per square centimeter over a surface of the copper foil. More preferably, the laser has a laser beam scanning speed of 0.35 to 0.45 second per square centimeter over a surface of the copper foil.

[0054] Preferably, the step 270 of drying the graphite powder is implemented in a step 272 under a temperature of 70 degrees Celsius to 90 degrees Celsius and a pressure of -10 Pa to -30 Pa to remove residues of the NMP from the graphite powder.

[0055] Compared to conventional battery7material recycling methods, the solutions provided by the present invention achieves advantageous technical effects of highly efficient recycling of copper foils and graphite powders and with lowered material resources wastes, lowered environmental pollutions as well as lowered energy7consumption. The copper foils and graphite powders obtained also have relatively high purity due to tire implementation of the method of the present invention as described herein.

[0056] This disclosure has been presented for purposes of illustration and description of the embodiments of the present invention, but is not intended to be exhaustive or limiting. For example, while the present invention is presented by making reference to one type of battery as illustrated in the drawings and the description, it should be appreciated that the present invention may be practiced for batteries of various other types, other structures other models and other architectures. Many modifications and variations will be apparent to those of ordinary skilled in the art. Tire example embodiments are chosen and described to explain principles and practical application of the present invention, and to enable those of ordinary skilled in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular technical solution contemplated and described. Further, while some technical details may be omitted from the description and drawings, for the purpose of clarity and conciseness, such omissions are not meant to be understood that the omitted features are necessarily absent or missing in the relevant structures, parts, processes and / or steps, as described herein, for understanding and practicing the invention.

[0057] Thus, although illustrative example embodiments have been described herein with reference to the accompanying drawings, it is to be understood that this description is not limiting and that various other changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the disclosure as sets out and defined the claims appended hereto.

Claims

Claims1. A method for recycling battery materials, the method comprising: soaking negative current collectors in a first solution for a predetermined soaking time period to cause an adhesive between a graphite coating and a copper foil to be dissolved in the first solution such that the graphite coating is separated from the copper foil and to cause tire graphite coating to be dispersed into the first solution to form graphite powders; extracting the copper foil from the first solution; drying the copper foil; and cleaning the copper foil,2. The method as recited in claim 1, further comprising: extracting the graphite powders from the first solution; and drying the graphite powder.

3. The method as recited in claim 2, wherein drying the graphite powder is implemented under a temperature of 70 degrees Celsius to 90 degrees Celsius and a pressure of -10 Pa to -30 Pa to remove residues of the NMP from the graphite powder.

4. The method as recited in any one of claims 1 to 3, wherein the first solution comprises NMP (N-Methyl-2-Pyrrolidone).

5. The method as recited in claim 4, wherein the first solution has a temperature between 70 degrees Celsius to 90 degrees Celsius during soaking the negative current collectors.

6. The method as recited in claim 4, wherein the predetermined soaking time period is 40 minutes to 60 minutes.

7. The method as recited in claim 1, further comprising subjecting the first solution to an ultrasonic oscillation for a predetermined processing time during soaking thenegative current collector in the first solution, to separate the graphite coating from the copper foil.

8. The method as recited in claim 7, wherein the ultrasonic oscillation has a power of 300 watts to 800 watts and a frequency of 30 KHz to 50KHz frequency, and the predetermined processing time is 5 to 15 minutes.

9. The method as recited in claim 1, wherein drying the copper foil is implemented under a baking temperature of 200 degrees Celsius to 230 degrees Celsius and a pressure of - 10 Pa to -30 Pa to remove residues of the NMP from the copper foil .

10. The method as recited in claim 1, wherein cleaning the copper foil comprises cleaning the copper foil to remove oxides, adhesive particles and carbon powders from the copper foil.11 . The method as recited in claim 10, wherein cleaning the copper foil comprises laserablating the copper foil to remove oxides, adhesive particles and carbon powders from the copper foil.

12. The method as recited in claim 11, wherein the laser is a MOPA laser and the laserablating the copper foil is implemented under a laser beam scanning speed of 0.3 - 0.5 second per square centimeter over a surface of the copper foil.

13. The method as recited in claim 12, wherein laser ablating forms a surface texture on the copper foil.

14. The method as recited in claim 13, wherein the surface texture comprises grooves and ridges with a pitch of 10 micrometers between the grooves and ndges.

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