RECOVERY PROCESSING METHOD FOR SPENT BATTERY ELECTRODE PLATE

Abstract

Disclosed is a method for recovering and processing a retired battery electrode plate. The method includes disassembling a retired battery to obtain an electrode plate, energizing two ends of the electrode plate until a binder on the electrode plate is heated and melted, and then separating out an electrode material and a current collector, and when the electrode plate is a negative electrode plate, ball milling the separated electrode material, winnowing the ball-milled material to obtain graphite, subjecting the graphite to an alkali treatment, adding the graphite, which has been subjected to the alkali treatment, and an aggregate to softened asphalt, and stirring same to obtain conductive asphalt. The two ends of the electrode are energized, such that the binder is melted into liquid to flow out of the current collector, and the electrode material is stripped off the electrode plate.

Claims

1. A method for recycling an electrode plate of a decommissioned battery, comprising: S1: disassembling a decommissioned battery to obtain the electrode plate, electrifying both ends of the electrode plate until a binder on the electrode plate is heated and melted, and then separating out an electrode material and a current collector; S2: when the electrode plate is a negative plate, ball-milling the electrode material, performing winnowing on a ball-milled material to obtain graphite, and subjecting the graphite to alkali treatment; and S3: adding the graphite after the alkali treatment in step S2 and an aggregate into a softened asphalt, and stirring a resulting material to obtain a conductive asphalt.

2. The method according to claim 1, wherein in step S1, when the electrode plate is a positive plate, the electrode material is one of lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium cobalt oxide or lithium manganate.

3. The method according to claim 1, wherein in step S1, a power supply for the electrifying has a voltage of 12 V to 72 V and a current of 1 A to 5 A.

4. The method according to claim 1, wherein in step S1, the binder on the electrode plate is heated and melted at a temperature ranging from 180? C. to 250? C.

5. The method according to claim 1, wherein in step S1, the electrifying lasts for 10 minutes to 60 minutes.

6. The method according to claim 1, wherein in step S2, the alkali used for the alkali treatment has a concentration of 0.1 mol/L to 1 mol/L.

7. The method according to claim 1, wherein in step S2, the ball-milled material has a particle size of 11 ?m to 18 ?m.

8. The method according to claim 1, wherein in step S2, the alkali used for the alkali treatment is one or more of sodium hydroxide, potassium hydroxide, aqueous ammonia, quaternary ammonium hydroxide or tetramethylammonium hydroxide.

9. The method according to claim 1, wherein in step S3, a dosage of the graphite is 1% to 10% of a mass of the asphalt.

10. The method according to claim 1, wherein in step S3, the aggregate is selected from one or more of AC-9, AC-13, AC-16, AC-19, AC-26 or AC-31.

11. The method according to claim 3, wherein in step S1, the electrifying lasts for 10 minutes to 60 minutes.

12. The method according to claim 6, wherein in step S2, the alkali used for the alkali treatment is one or more of sodium hydroxide, potassium hydroxide, aqueous ammonia, quaternary ammonium hydroxide or tetramethylammonium hydroxide.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0027] The present disclosure will be further explained with reference to the accompanying drawings and embodiments hereinafter, where:

[0028] FIG. 1 is a process flowchart of Embodiment 1 of the present disclosure;

[0029] FIG. 2 is a schematic diagram showing two heating structures of a positive plate and a negative plate of the present disclosure;

[0030] FIG. 3 is a diagram showing a relationship between a doping amount of graphite and a conductive performance of conductive asphalt in Embodiment 1 of the present disclosure; and

[0031] FIG. 4 is a diagram showing a relationship between the doping amount of the graphite and a melting time of ice and snow in Embodiment 1 of the present disclosure.

DETAILED DESCRIPTION

[0032] The concepts and the technical effects produced of the present disclosure will be clearly and completely described in conjunction with the embodiments and the accompanying drawings so as to sufficiently understand the objects, the features and the effects of the present disclosure. Obviously, the described embodiments are merely some embodiments of the disclosure, rather than all the embodiments. Other embodiments obtained by those skilled in the art without going through any creative effort shall all fall within the protection scope of the disclosure.

Embodiment 1

[0033] A method for recycling an electrode plate of a decommissioned battery, referring to FIG. 1, includes the following steps of: [0034] (1) dismantling a battery after deep discharge, classifying a case, a positive plate, a diaphragm and a negative plate of the battery respectively by manual sorting, heating the positive plate and the negative plate to 180? C. by internal resistances of the electrode plates under the action of 12 V and an applied current of 1 A respectively, and keeping heating for 10 minutes, so that a positive material was separated from an aluminum foil, and a negative material (including graphite and a small amount of PVDF) was separated from a copper foil; [0035] (2) transferring the exfoliated negative material to a ball mill for ball-milling at 200 r/min for 6 hours to obtain a ball-milled material with a particle size of 11 ?m to 18 ?m, pouring the ball-milled material into a horizontal winnower mill, and sorting the material at a rotating speed of 1,000 r/min, where the material close to the horizontal winnower mill was graphite and the material far from the horizontal winnower mill was PVDF; a purity of graphite obtained by this sorting method was over 98%, and a recycling rate of graphite was 95%; [0036] (3) adding the graphite into 0.1 mol/L NaOH solution and soaking for 30 minutes, alkalizing functional groups on a surface of the graphite, and then washing and drying; and [0037] (4) heating purchased industrial asphalt at 170? C., adding graphite which accounts for 1% of a mass of the asphalt after the asphalt was softened, then adding an AC-9 aggregate, a dosage of the asphalt being 5% of a dosage of the aggregate, and uniformly mixing with a stirrer to obtain conductive asphalt.

[0038] FIG. 2 is a schematic diagram showing two heating structures of positive and negative plates. In this figure, the upper and lower parts of FIG. a on the left are positive and negative plates of an external power supply. The positive and negative plates are in contact with the positive material, the aluminum foil is disposed between the positive materials. The upper and lower parts on the right are positive and negative plates of the external power supply. The positive and negative plates are in contact with the negative material, the copper foil is disposed between the negative materials. In this figure, FIG. b on the left shows a roller electrode. Upper and lower rollers are respectively connected with different electrodes respectively, the positive material and the aluminum foil are disposed between the rollers, the upper and lower rollers on the right are connected with different electrodes respectively, and the negative material and the copper foil are disposed between the rollers.

Embodiment 2

[0039] A method for recycling an electrode plate of a decommissioned battery includes the following steps of: [0040] (1) dismantling a battery after deep discharge, classifying a case, a positive plate, a diaphragm and a negative plate of the battery respectively by manual sorting, heating the positive plate and the negative plate to 190? C. by internal resistances of the electrode plates under the action of 36 V and an applied current of 1 A respectively, and keeping heating for 10 minutes, so that a positive material was separated from an aluminum foil, and a negative material (including graphite and a small amount of PVDF) was separated from a copper foil; [0041] (2) transferring the exfoliated negative material to a ball mill for ball-milling at 200 r/min for 6 hours to obtain a ball-milled material with a particle size of 11 ?m to 18 ?m, and separating the graphite from the PVDF by winnowing according to a density difference; a purity of graphite obtained by this sorting method was over 98%, and a recycling rate of graphite was 95%; [0042] (3) adding the graphite into 0.2 mol/L NaOH solution and soaking for 30 minutes, alkalizing functional groups on a surface of the graphite, and then washing and drying; and [0043] (4) heating purchased industrial asphalt at 170? C., adding graphite which accounts for 2% of a mass of the asphalt after the asphalt was softened, then adding an AC-13 aggregate, a dosage of the asphalt being 5% of a dosage of the aggregate, and uniformly mixing with a stirrer to obtain conductive asphalt.

Embodiment 3

[0044] A method for recycling an electrode plate of a decommissioned battery includes the following steps of: [0045] (1) dismantling a battery after deep discharge, classifying a case, a positive plate, a diaphragm and a negative plate of the battery respectively by manual sorting, heating the positive plate and the negative plate to 200? ? C. by internal resistances of the electrode plates under the action of 36 V and an applied current of 5 A respectively, and keeping heating for 30 minutes, so that a positive material was separated from an aluminum foil, and a negative material (including graphite and a small amount of PVDF) was separated from a copper foil; [0046] (2) transferring the exfoliated negative material to a ball mill for ball-milling at 200 r/min for 6 hours to obtain a ball-milled material with a particle size of 11 ?m to 18 ?m, and separating the graphite from the PVDF by winnowing according to a density difference; a purity of graphite obtained by this sorting method was over 98%, and a recycling rate of graphite was 95%; [0047] (3) adding the graphite into 0.1 mol/L KOH solution and soaking for 30 minutes, alkalizing functional groups on a surface of the graphite, and then washing and drying; and [0048] (4) heating purchased industrial asphalt at 170? ? C., adding graphite which accounts for 4% of a mass of the asphalt after the asphalt was softened, then adding an AC-16 aggregate, a dosage of the asphalt being 5% of a dosage of the aggregate, and uniformly mixing with a stirrer to obtain conductive asphalt.

Embodiment 4

[0049] A method for recycling an electrode plate of a decommissioned battery includes the following steps of: [0050] (1) dismantling a battery after deep discharge, classifying a case, a positive plate, a diaphragm and a negative plate of the battery respectively by manual sorting, heating the positive plate and the negative plate to 220? ? C. by internal resistances of the electrode plates under the action of 36 V and an applied current of 1 A respectively, and keeping heating for 40 minutes, so that a positive material was separated from an aluminum foil, and a negative material (including graphite and a small amount of PVDF) was separated from a copper foil; [0051] (2) transferring the exfoliated negative material to a ball mill for ball-milling at 200 r/min for 6 hours to obtain a ball-milled material with a particle size of 11 ?m to 18 ?m, and separating the graphite from the PVDF by winnowing according to a density difference; a purity of graphite obtained by this sorting method was over 98%, and a recycling rate of graphite was 95%; [0052] (3) adding the graphite into 0.1 mol/L NH.sub.3.Math.H.sub.2O solution and soaking for 30 minutes, alkalizing functional groups on a surface of the graphite, and then washing and drying; and [0053] (4) heating purchased industrial asphalt at 170? ? C., adding graphite which accounts for 5% of a mass of the asphalt after the asphalt was softened, then adding an AC-19 aggregate, a dosage of the asphalt being 5% of a dosage of the aggregate, and uniformly mixing with a stirrer to obtain conductive asphalt.

Embodiment 5

[0054] A method for recycling an electrode plate of a decommissioned battery includes the following steps of: [0055] (1) dismantling a battery after deep discharge, classifying a case, a positive plate, a diaphragm and a negative plate of the battery respectively by manual sorting, heating the positive plate and the negative plate to 250? C. by internal resistances of the electrode plates under the action of 36 V and an applied current of 1 A respectively, and keeping heating for 10 minutes, so that a positive material was separated from an aluminum foil, and a negative material (including graphite and a small amount of PVDF) was separated from a copper foil; [0056] (2) transferring the exfoliated negative material to a ball mill for ball-milling at 200 r/min for 6 hours to obtain a ball-milled material with a particle size of 11 ?m to 18 ?m, and separating the graphite from the PVDF by winnowing according to a density difference; a purity of graphite obtained by this sorting method was over 98%, and a recycling rate of graphite was 95%; [0057] (3) adding the graphite into 0.1 mol/L tetramethylammonium hydroxide solution and soaking for 30 minutes, alkalizing functional groups on a surface of the graphite, and then washing and drying; and [0058] (4) heating purchased industrial asphalt at 170? ? C., adding graphite which accounts for 10% of a mass of the asphalt after the asphalt was softened, then adding an AC-31 aggregate, a dosage of the asphalt being 5% of a dosage of the aggregate, and uniformly mixing with a stirrer to obtain conductive asphalt.

Comparative Example 1

[0059] In this comparative example, an ordinary asphalt concrete was prepared, which was different from Embodiment 1 in that no graphite was added, and the specific process was as follows:

[0060] heating asphalt at 170? C., adding an AC-9 aggregate after the asphalt was softened, a dosage of the asphalt being 5% of a dosage of the aggregate, and uniformly mixing with a stirrer to obtain asphalt concrete.

Comparative Example 2

[0061] A method for recycling an electrode plate of a decommissioned battery was different from Embodiment 2 in that the alkali treatment of step (3) was not needed, and the specific process was as follows: [0062] (1) dismantling a battery after deep discharge, classifying a case, a positive plate, a diaphragm and a negative plate of the battery respectively by manual sorting, heating the positive plate and the negative plate to 190? ? C. by internal resistances of the electrode plates under the action of 36 V and an applied current of 1 A respectively, and keeping heating for 10 minutes, so that a positive material was separated from an aluminum foil, and a negative material (including graphite and a small amount of PVDF) was separated from a copper foil; [0063] (2) transferring the exfoliated negative material to a ball mill for ball-milling at 200 r/min for 6 hours to obtain a ball-milled material with a particle size of 11 ?m to 18 ?m, and separating the graphite from the PVDF by winnowing according to a density difference; a purity of graphite obtained by this sorting method was over 98%, and a recycling rate of graphite was 95%; and [0064] (3) heating purchased industrial asphalt at 170? ? C., adding graphite which accounts for 10% of a mass of the asphalt after the asphalt was softened, then adding an AC-13 aggregate, a dosage of the asphalt being 5% of a dosage of the aggregate, and uniformly mixing with a stirrer to obtain conductive asphalt.

Experimental Example

1. Resistivity Test:

[0065] (1) The conductive asphalt prepared in Embodiments 1 to 5 and Comparative Example 1 was made into Marshall specimens with a diameter of 101.6 mm?63.5 mm, and resistivities of the prepared Marshall specimens were tested by a two-electrode method. A volt ampere characteristic curve was measured by Keithley-2450 SourceMeter, and a scanning voltage ranged from 0 V to 5 V. The results were shown in Table 1.

TABLE-US-00001 TABLE 1 Test results of asphalt resistivity Comparative Embodiment Embodiment Embodiment Embodiment Embodiment Example 1 1 2 3 4 5 Resistivity (? .Math. m) 3.2 ? 10.sup.9 0.97 ? 10.sup.8 6.2 ? 10.sup.7 89 28 21 [0066] (2) On the basis of Embodiment 1, a doping amount of the graphite in step (4) was adjusted to 0 wt % to 6 wt %, and the test result of the resistivity thereof was shown in FIG. 3. It can be seen from FIG. 3 that the higher the doping amount of the graphite is, the lower the resistivity is, indicating that with the increased content of the graphite, the graphite forms a conductive network in the asphalt, and the conductivity of the asphalt is enhanced.

2. Test on Ice and Snow Melting:

[0067] (1) The conductive asphalt was made into specimens of 150 mm?50 mm?20 mm, a plurality of 10 ml of pure water was respectively taken to prepare ice cubes at a low temperature of ?10? C.?1? C., put ice cubes of uniform size and equal mass on the test specimens of Embodiments 1 to 5 and Comparative Example 1 in a thermotank of 0? ? C., and then a voltage of 36 V and a current of 5 A are applied to both sides of the specimens for test on ice and snow melting. The results were shown in Table 2.

TABLE-US-00002 TABLE 2 Test results on ice and snow melting of asphalt Comparative Embodiment Embodiment Embodiment Embodiment Embodiment Example 1 1 2 3 4 5 Melting time (h) >10 >10 9 1.4 2 2.4 [0068] (2) On the basis of Embodiment 1, a doping amount of the graphite in step (4) was adjusted to 0 wt % to 6 wt %, and the test result of the ice and snow melting thereof was shown in FIG. 4. It can be seen from FIG. 4 that with the increased content of the graphite, the melting time of ice and snow becomes shorter. When the doping amount reaches 4 wt %, the thawing time is shortest. After that, with the increased content of the graphite, the melting time increases somewhat. This is because that, according to the calculation based on the formula Q=I.sup.2Rt, when the doping amount of the graphite is small, the conductive asphalt cannot form an effective conductive network, resulting in high resistance and no effective internal current, leading to low heat generation, and conversely, when the amount of graphite is excessive, the resistance is low and the current is high. Therefore, when the doping amount of the graphite is moderate, the heat yield is maximum.

3. Compressive Strength Test

[0069] The conductive asphalt prepared in Embodiments 1 to 5 and Comparative Example 2 was tested for compressive strength by a compressive strength tester, with a compression speed of 12 mm/min and a contact area of 140 cm.sup.2. Table 3 showed the pH and compressive strength test results of Embodiments 1 to 5 and Comparative Example 2 after alkali treatment.

TABLE-US-00003 TABLE 3 pH and compressive strength test results after alkali treatment Comparative Embodiment Embodiment Embodiment Embodiment Embodiment Example 2 1 2 3 4 5 pH 6.3 7.9 8.3 8.1 7.6 8.6 Ultimate compressive 25.8 27.4 28.2 27.8 27.1 26.7 strength (Mpa)

[0070] The embodiments of the present disclosure are described in detail with reference to the drawings above, but the present disclosure is not limited to the above embodiments, and various changes may also be made within the knowledge scope of those of ordinary skills in the art without departing from the purpose of the present disclosure. In addition, in case of no conflict, the embodiments in the application and the features in the embodiments may be combined with each other.