JP2022049831A - Lithium-ion battery recycling method and recycling equipment - Google Patents

Abstract

To improve the recovery amount of lithium contained in a lithium-ion battery.SOLUTION: A lithium-ion battery recycling method includes a first discharge step S102 of discharging a lithium ion battery through a load in a first resistance range to increase the amount of lithium contained in a positive electrode active material, a second discharge step S104 of further discharging the lithium ion battery through the load in a second resistance range lower than the first resistance range to further increase the amount of lithium contained in the positive electrode active material, and a recovery step S108 of recovering the positive electrode active material from the lithium ion battery after the second discharge step S104.SELECTED DRAWING: Figure 3

Description

The present invention relates to a method for recycling a lithium ion battery and a recycling facility.

Conventionally, lithium ion batteries have been widely used in mobile devices such as smart phones, hybrid vehicles, electric vehicles, and the like. In recent years, lithium-ion batteries have also attracted attention as large-capacity batteries for stationary power sources in buildings, offices, and power plants. Such lithium-ion batteries contain various substances that are desired to be reused, and various methods for recovering reusable substances from used lithium-ion batteries have been proposed. For example, Patent Document 1 describes lithium ions dispersed in a lithium ion battery by immersing the lithium ion battery in a conductive liquid containing an electrolyte to discharge the charge remaining in the lithium ion battery. It is disclosed that the lithium recovery amount is maximized by concentrating the inside of the positive electrode active material.

Japanese Unexamined Patent Publication No. 2012-074247

However, even if the method of Patent Document 1 is used, the lithium contained in the lithium ion battery may not be sufficiently recovered. The present invention has been made in view of this problem, and an object of the present invention is to improve the recovery amount of lithium contained in a lithium ion battery.

The method for recycling a lithium ion battery according to one aspect of the present invention includes a first discharging step of discharging the lithium ion battery through a load in the first resistance value range to increase the amount of lithium contained in the positive electrode active material. A second discharge step of further discharging the lithium ion battery through a load in the second resistance value range lower than the first resistance value range to further increase the amount of lithium contained in the positive electrode active material, and a second. It includes a recovery step of recovering the positive electrode active material from the lithium ion battery after the discharge step.

Even with a used lithium-ion battery, the voltage may be high at the initial stage of discharge, and the current value tends to increase. For this reason, sparks may occur. First, since the lithium ion battery is discharged through a load in the first resistance value range having a relatively high resistance value in the first discharge step, lithium contained in the positive electrode active material is prevented from excessively increasing the current value. The amount of can be increased to some extent. The voltage of the lithium ion battery drops to some extent due to the discharge in the first discharge step. Next, the amount of lithium contained in the positive electrode active material can be further increased by further discharging the lithium ion battery through a load in the second resistance value range lower than the first resistance value range. This makes it possible to improve the amount of lithium recovered from the positive electrode active material. Further, since the voltage of the lithium ion battery is lowered to some extent by the discharge in the first discharge step, even if the lithium ion battery is discharged through a load in the second resistance value range lower than the first resistance value range. It prevents the current value from becoming excessively large. This prevents the generation of sparks.

In the first discharge step, the first load having the first resistance value may be used, and in the second discharge step, the second load having the second resistance value lower than the first resistance value may be used. ..

Further, at the time of switching from the first discharge step to the second discharge step, the lithium ion battery may be discharged with both the first load and the second load connected to the lithium ion battery in parallel. ..

If the first load and the lithium ion battery are electrically disconnected at the time of switching from the first discharge step to the second discharge step, the discharge of the lithium ion battery is interrupted, so that the voltage of the lithium ion battery may rise again. If a second load having a low resistance value and a lithium ion battery are electrically connected in this state, the current value may become excessively large. On the other hand, when switching from the first discharge process to the second discharge process, the lithium ion battery is discharged with both the first load and the second load connected to the lithium ion battery in parallel. For example, since the discharge of the lithium-ion battery is not interrupted, the voltage of the lithium-ion battery does not rise again. Therefore, it is prevented that the current value becomes excessively large at the time of switching.

Further, the load is a variable resistance load, and the variable resistance load may be adjusted so that the resistance value becomes lower in the second discharge step than in the first discharge step.

Even when a variable resistance load is used in this way, the resistance value continuously decreases when switching from the first discharge process to the second discharge process, and the discharge of the lithium ion battery is not interrupted. The voltage does not rise again. Therefore, it is prevented that the current value becomes excessively large.

Further, the lithium ion battery recycling facility according to one aspect of the present invention is a first discharge that discharges the lithium ion battery through a load in the first resistance value range to increase the amount of lithium contained in the positive electrode active material. The step and the second discharge step of further discharging the battery through the load in the second resistance value range lower than the first resistance value range to further increase the amount of lithium contained in the positive electrode active material are executed. It includes a possible discharge device and a recovery device for recovering the positive electrode active material from the lithium ion battery.

The discharge device has a first load having a first resistance value for the first discharge step and a second load having a second resistance value lower than the first resistance value for the second discharge step. And may be provided.

Further, the discharge device discharges the lithium ion battery in a state where both the first load and the second load are connected to the lithium ion battery in parallel at the time of switching from the first discharge step to the second discharge step. It may be configured in.

Further, the load is a variable resistance load, and the discharge device includes a control unit configured to adjust the variable resistance load so that the resistance value is lower in the second discharge step than in the first discharge step. May be good.

According to the present invention, it is possible to improve the recovery amount of lithium contained in the lithium ion battery.

A block diagram schematically showing the configuration of a recycling facility for a lithium ion battery according to a first embodiment of the present invention. Block diagram showing the configuration of the discharge device of the recycling facility Flow chart showing the recycling method by the recycling equipment Graph showing the resistance value of the load of the discharge device A block diagram schematically showing the configuration of the discharge device according to the second embodiment of the present invention. Graph showing the resistance value of the load of the discharge device A block diagram schematically showing the configuration of the discharge device according to the third embodiment of the present invention. A block diagram schematically showing the configuration of the discharge device according to the fourth embodiment of the present invention. A block diagram schematically showing the configuration of the discharge device according to the fifth embodiment of the present invention. A block diagram schematically showing the configuration of the discharge device according to the sixth embodiment of the present invention.

As shown in FIG. 1, the lithium ion battery recycling equipment 10 of the first embodiment of the present invention includes a discharge device 12, a disassembly device 14, and a recovery device 16. The discharge device 12 has a first discharge step of discharging the lithium ion battery 18 through a load in the first resistance value range to increase the amount of lithium contained in the positive electrode active material, and a first resistance value range. It is possible to carry out a second discharge step of further discharging the lithium ion battery 18 through a load in the lower second resistance range to further increase the amount of lithium contained in the positive electrode active material. More specifically, as shown in FIG. 2, the discharge device 12 is based on the first load 24 of the first resistance value for the first discharge step and the first resistance value for the second discharge step. It also comprises a second load 26, which has a lower second resistance value.

The first load 24 is, for example, a resistor. The first resistance value range is, for example, 1 k to 1000 kΩ. The second load 26 is also, for example, a resistor. The second resistance value range is, for example, 0.001 to 0.5Ω. If the resistance value is in the second resistance value range, the second load 26 may be a conductor such as a wire rod for wiring or a printed wiring instead of the resistor.

The discharge device 12 further includes a switch 28 for turning on / off the connection between the second load 26 and the lithium ion battery 18, and a voltmeter 30 for detecting the voltage of the lithium ion battery 18. .. With the switch 28 turned off, only the first load 24 is connected to the lithium ion battery 18, whereby the first discharge step is executed. Further, the second load 26 is connected to the lithium ion battery 18 in a state where the switch 28 is ON, whereby the second discharge step is executed. Further, the discharge device 12 is a lithium ion battery in a state where both the first load 24 and the second load 26 are connected in parallel to the lithium ion battery 18 at the time of switching from the first discharge step to the second discharge step. It is configured to discharge 18. In the first embodiment, the first load 24 is connected to the lithium ion battery 18 together with the second load 26 also in the second discharge step after switching from the first discharge step to the second discharge step. ing. The total resistance value of the first load 24 and the second load 26 connected to the lithium ion battery 18 in parallel is close to the resistance value of only the second load 26, and is within the second resistance value range. be. The total resistance value of the first load 24 and the second load 26 is slightly lower than the resistance value of the second load 26 alone.

The discharge device 12 further includes a control unit 32. The control unit 32 includes a computer, a digital logic circuit, a relay logic circuit, and the like, and is electrically connected to the switch 28 and the voltmeter 30. In the control unit 32, the switch 28 is turned off (first discharge step) when the voltage V of the lithium ion battery 18 is equal to or higher than the threshold VL, and the switch 28 is turned on (second discharge step) when the voltage V of the lithium ion battery 18 is less than the threshold VL. It is configured to control the switch 28 so as to be. Further, the control unit 32 is configured to emit a signal for notifying by a sound and / or a visual means such as a lamp when the second discharge process is continued for a predetermined time. Further, the discharge device 12 includes an adapter (not shown) for holding the lithium ion battery 18 so that the lithium ion battery 18 is electrically connected to the first load 24 and / or the second load 26. ing.

The lithium ion battery 18 is a laminated type. More specifically, in the lithium ion battery 18, a plurality of unit cells having a positive electrode 20, a separator (not shown), and a negative electrode 22 arranged side by side in this order are laminated in series and housed in a flexible container. It was done. Although the lithium ion battery 18 is drawn in a long shape in the stacking direction of the unit cells in FIG. 2, each unit cell of the lithium ion battery 18 is a plate-like body, and the lithium ion battery 18 is also shown as a whole in FIG. It may be a plate-like body having a shorter dimension in the stacking direction than the shape drawn in.

The positive electrode 20 has a structure in which a layered positive electrode active material portion is formed on the surface of the sheet-shaped positive electrode current collector on the separator side. The positive electrode current collector is, for example, a resin collector of a conductive resin, or a resin collector in which a non-conductive polymer material and a conductive filler are mixed. The non-conductive polymer material is a polyolefin such as polyethylene or polypropylene. The conductive filler is, for example, a carbon material such as acetylene black or a metal such as aluminum. Further, the positive electrode current collector may be a metal current collector such as aluminum foil.

The positive electrode active material portion is a mixture of positive electrode active material particles and an electrolytic solution. The positive electrode active material portion is in a semi-solid state called, for example, a slurry, a funicular, or a pendulum. The positive electrode active material particles are LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiFePO ₄ , a ternary material, and the like. The surface of the positive electrode active material particles may be coated with a coating resin. Further, the positive electrode active material portion may contain a conductive auxiliary agent. The conductive auxiliary agent is, for example, a carbon material such as acetylene black or a metal such as aluminum. The coating resin that coats the positive electrode active material particles may also contain a conductive filler made of the same material as the conductive auxiliary agent. Further, the positive electrode active material portion may contain a binder. The binder is, for example, polyvinylidene fluoride or the like. The electrolytic solution contains an electrolyte and a non-aqueous solvent. The electrolytes are LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , and the like. The non-aqueous solvent is a lactone compound, a cyclic or chain carbonate ester, a chain carboxylic acid ester, a cyclic or chain ether, a phosphoric acid ester, a nitrile compound, an amide compound, a sulfone, a sulfone, or a mixture thereof.

The negative electrode 22 has a structure in which the negative electrode active material portion is formed in a layer on the surface of the sheet-shaped negative electrode current collector on the separator side. The negative electrode current collector is the same as the positive electrode current collector, and is a resin current collector or a metal current collector such as a copper foil. The negative electrode active material portion is a mixture of negative electrode active material particles and an electrolytic solution. The negative electrode active material portion is also in a semi-solid state called, for example, slurry, funicular, or pendulum. The negative electrode active material particles are carbon-based active materials such as graphitizable carbon (hard carbon) and graphite, metals, alloys, or oxides. The surface of the negative electrode active material particles may also be coated with a coating resin. Further, the negative electrode active material portion may also contain the same conductive auxiliary agent as the conductive auxiliary agent contained in the positive electrode active material portion. The coating resin that coats the negative electrode active material particles may also contain a conductive filler made of the same material as the conductive auxiliary agent. Further, the negative electrode active material portion may contain a binder. The binder is an aqueous polymer such as a styrene-butadiene copolymer. The electrolytic solution contained in the negative electrode active material portion is the same as the electrolytic solution contained in the positive electrode active material portion.

The separator is a microporous film of polyolefin such as polyethylene and polypropylene. The peripheral edge of the separator is held by a frame (not shown). The positive electrode current collector and the negative electrode current collector are installed so as to sandwich the frame. The positive electrode active material portion is housed in a space surrounded by a positive electrode current collector, a separator and a frame. The negative electrode active material portion is housed in a space surrounded by a negative electrode current collector, a separator and a frame.

The dismantling device 14 includes a cutter for cutting and opening the container 34 of the lithium ion battery 18, a take-out device for taking out a unit cell from the container 34, and the like. The recovery device 16 is a peeling device that holds the frame of each unit cell and peels off the positive electrode current collector and the negative electrode current collector on both sides of the frame, and scrapes the positive electrode active material portion and the negative electrode active material portion from the separator. Equipped with a removing device, etc. The recovery device 16 includes a heating device for heating the fixed portion between the positive electrode current collector and the negative electrode current collector and the frame so that the positive electrode current collector and the negative electrode current collector can be easily peeled off. May be good. Further, the recovery device 16 includes a liquid supply device that separates the positive electrode active material portion and / or the negative electrode active material portion from the separator by spraying liquid onto the positive electrode active material portion and / or the negative electrode active material portion on both sides of the separator. May be good.

Next, a method of recycling the lithium ion battery by the lithium ion battery recycling facility 10 will be described with reference to the flowchart shown in FIG. First, the lithium ion battery 18 is set in the discharge device 12. The control unit 32 detects the voltage V of the lithium ion battery 18 by the voltmeter 30, controls the switch 28 so that the switch 28 is turned off when the voltage V is equal to or higher than the threshold value VL, and discharges the lithium ion battery 18. (S102: first discharge step). As a result, as shown in FIG. 4, the positive electrode 20 and the negative electrode 22 of the lithium ion battery 18 are electrically connected via the first load 24 in the first resistance value range having a relatively high resistance value. On the other hand, the positive electrode 20 and the negative electrode 22 of the lithium ion battery 18 are not electrically connected via the second load 26 in the second resistance value range having a relatively low resistance value. Therefore, a certain amount of lithium ions contained in the negative electrode active material portion moves to the positive electrode active material portion of the positive electrode 20 while preventing the current value from becoming excessively large. This makes it possible to increase the amount of lithium contained in the positive electrode active material. In addition, the voltage of the lithium ion battery drops to some extent due to the discharge in the first discharge step S102.

When the voltage V drops below the threshold value VL, the control unit 32 controls the switch 28 so that the switch 28 is turned on to discharge the lithium ion battery 18 (S104: second discharge step). As shown in FIG. 4, the positive electrode 20 and the negative electrode 22 are electrically connected via the second load 26 in the second resistance value range lower than the first resistance value range to further connect the lithium ion battery 18. Discharge. Therefore, the remaining lithium ions contained in the negative electrode active material portion move to the positive electrode active material portion of the positive electrode 20. This makes it possible to further increase the amount of lithium contained in the positive electrode active material. Therefore, it is possible to improve the amount of lithium recovered from the positive electrode active material portion of the positive electrode 20. In the second discharge step S102, the first load 24 is also connected to the battery 18, but the total of the first load 24 and the second load 26 connected to the lithium ion battery 18 in parallel as described above. The resistance value is also in the second resistance value range, which is slightly lower than the resistance value of the second load 26 alone. Further, since the voltage of the lithium ion battery 18 is lowered to less than the threshold value VL due to the discharge in the first discharge step S102, the voltage 26 is passed through the second load 26 in the second resistance value range lower than the first resistance value range. Even if the positive electrode 20 and the negative electrode 22 are electrically connected, the current value is prevented from becoming excessively large. Therefore, no sparks are generated.

Further, when the first load 24 and the lithium ion battery 18 are electrically disconnected at the time of switching from the first discharge step S102 to the second discharge step S104, the discharge of the lithium ion battery 18 is interrupted, so that the voltage of the lithium ion battery 18 is reached. May rise again. If the second load 26 having a low resistance value and the lithium ion battery 18 are electrically connected in this state, the current value may become excessively large. On the other hand, in the first embodiment, both the first load 24 and the second load 26 are connected to the lithium ion battery 18 in parallel at the time of switching from the first discharge step S102 to the second discharge step S104. The battery 24 is discharged. That is, since the electrical connection between the first load 24 and the lithium ion battery 18 continues, the discharge of the lithium ion battery 18 is not interrupted, and the voltage of the lithium ion battery 18 does not rise again. Therefore, it is prevented that the current value becomes excessively large. In the first embodiment, both the first load 24 and the second load 26 are used not only at the time of switching from the first discharge step S102 to the second discharge step S104 but also in the subsequent second discharge step S104. Although it is connected to the lithium ion battery 18 in parallel, for example, a switch for turning on / off the connection between the first load 24 and the lithium ion battery 18 is further provided, and after switching to the second discharge step S104, The control unit 32 may control these switches so that the connection between the first load 24 and the lithium ion battery 18 is turned off and the lithium ion battery 18 is discharged only through the second load 26.

Next, in the dismantling device 14, the container 34 of the lithium ion battery 18 is cut and opened by the cutter, and the unit cell is taken out from the container 34 by the taking-out device (S106: dismantling step). Further, in the recovery device 16, the positive electrode current collector and the negative electrode current collector on both sides of the frame are peeled off while the frame of each unit cell is held by the peeling device, and the positive electrode active material portion and the negative electrode are peeled off from both sides of the separator by the scraping device. The active material portion is scraped off (S108: recovery step). The positive electrode active material portion and / or the negative electrode active material portion on both sides of the separator may be sprayed with a liquid by the liquid supply device to separate the positive electrode active material portion and / or the negative electrode active material portion from the separator. By heat-treating (roasting) the separated positive electrode active material portion and / negative electrode active material portion, the conductive auxiliary agent and / or the binder is decomposed and removed. Further, by immersing the positive electrode active material portion in water, particles of the positive electrode active material containing a large amount of lithium can be recovered. Further, it is also possible to immerse the positive electrode active material portion in an acidic aqueous solution such as sulfuric acid to obtain a metal ion solution containing lithium or the like, and further recover the metal such as lithium by a method such as ion exchange, electrolysis, or precipitation separation. .. Further, the particles of the negative electrode active material can be recovered by immersing the negative electrode active material portion in water or an acidic aqueous solution.

Next, a second embodiment of the present invention will be described. As shown in FIG. 5, the discharge device 40 of the second embodiment includes a variable resistance load 42 in place of the first load 24 and the second load 26 of the discharge device 12 of the first embodiment. The switch 28 is not provided. Further, the control unit 32 is electrically connected to the variable resistance load 42, and adjusts the variable resistance load 42 so that the resistance value of the variable resistance load 42 is lower in the second discharge step S104 than in the first discharge step S102. It is configured to do. Since the other configurations are the same as those in the first embodiment, the same components will be designated by the same reference numerals as those in FIGS. 1 to 3, and the description thereof will be omitted.

As shown in FIG. 6, in the first discharge step S102, the control unit 32 adjusts the resistance value of the variable resistance load 42 in the same manner as the resistance value of the first load 24 of the first embodiment. Further, in the second discharge step S104, the control unit 32 adjusts the resistance value of the variable resistance load 42 in the same manner as the resistance value of the second load 26 of the first embodiment. When the variable resistance load 42 is used in this way, the resistance value continuously decreases when switching from the first discharge step S102 to the second discharge step S104, and the discharge of the lithium ion battery 18 is not interrupted. The voltage of the ion battery 18 does not rise again. Therefore, it is prevented that the current value becomes excessively large.

Note that FIG. 6 shows an example in which the resistance value of the variable resistance load 42 is adjusted in the first discharge step S102 in the same manner as the resistance value of the first load 24 of the first embodiment. The variable resistance load 42 may be adjusted in the first discharge step S102 so that the resistance value continuously decreases as the voltage V of the lithium ion battery 18 detected by the voltmeter 30 decreases. By doing so, the time required for discharging in the first discharging step S102 can be shortened. Further, in the first discharge step S102 and / or the second discharge step S104, the variable resistance load 42 may be adjusted in still another embodiment.

Next, a third embodiment of the present invention will be described. As shown in FIG. 7, the discharge device 50 of the third embodiment selectively selects either the first load 24 or the second load 26 in place of the switch 28 of the discharge device 12 of the first embodiment. It includes a switch 52 installed so as to be electrically connected to the lithium ion battery 18. Since the other configurations are the same as those in the first embodiment, the same components will be designated by the same reference numerals as those in FIGS. 1 to 4, and the description thereof will be omitted. In the discharge device 50, the discharge of the lithium ion battery 18 is temporarily interrupted at the time of switching from the first discharge step S102 to the second discharge step S104, but the switching can be completed in a short time, so that the voltage of the lithium ion battery 18 can be increased. It can be prevented from rising again or suppressed to the extent that there is no practical problem.

Next, a fourth embodiment of the present invention will be described. As shown in FIG. 8, the discharge device 60 of the fourth embodiment includes a first discharge device 62 including a first load 24 and a second discharge device 64 including a second load 26. .. The first discharge device 62 executes the first discharge step S102, and the second discharge device 64 executes the second discharge step S104. Since the other configurations are the same as those in the first embodiment, the same components will be designated by the same reference numerals as those in FIGS. 1 to 4, and the description thereof will be omitted. The discharge device 60 involves the movement of the lithium ion battery 18 when switching from the first discharge step S102 to the second discharge step S104. For this reason, the discharge of the lithium ion battery 18 is temporarily interrupted, but conditions such as the type of the lithium ion battery 18, the discharge time of the first discharge step S102, and the resistance value of the first load 24 of the first discharge device 62 are adjusted. Therefore, it is possible to prevent the voltage of the lithium ion battery 18 from rising again or to suppress it to the extent that there is no practical problem.

Next, a fifth embodiment of the present invention will be described. As shown in FIG. 9, the discharge device 70 of the fifth embodiment replaces the first discharge device 62 and the second discharge device 64 of the fourth embodiment with the first discharge tank 72 and the second discharge tank 74. And have. The first discharge tank 72 executes the first discharge step S102, and the second discharge tank 74 executes the second discharge step S104. Since the other configurations are the same as those in the first embodiment, the same components will be designated by the same reference numerals as those in FIGS. 1, 3 and 4, and the description thereof will be omitted. The first discharge tank 72 contains the discharge liquid in the first resistance value range, and the second discharge tank 74 contains the discharge liquid in the second resistance value range. The discharge liquid contains electrolytes such as sodium chloride and sulfuric acid. The discharge liquid of the first discharge tank 72 and the discharge liquid of the second discharge tank 74 have different electrolyte concentrations and / or types. In the first discharge tank 72 and the second discharge tank 74, the positive electrode tab (not shown) connected to the positive electrode 20 of the lithium ion battery 18 and the negative electrode tab (not shown) connected to the negative electrode 22 come into contact with the discharge liquid. It is configured to hold and accommodate a plurality of lithium ion batteries 18. The discharge device 70 also temporarily interrupts the discharge due to the movement of the lithium ion battery 18 when switching from the first discharge step S102 to the second discharge step S104, but the type of the lithium ion battery 18 and the first discharge step S102 Depending on the conditions such as the resistance value of the first discharge liquid of the first discharge tank 72, the voltage of the lithium ion battery 18 can be prevented from rising again or suppressed to the extent that there is no practical problem. Further, according to the discharge tank, a large number of lithium ion batteries 18 can be discharged at one time.

Next, a sixth embodiment of the present invention will be described. As shown in FIG. 10, the discharge device 80 of the sixth embodiment includes a discharge tank 82, an electrolytic solution supply unit 84, and a control valve 86. The electrolytic solution supply unit 84 contains an electrolytic solution containing an electrolyte. The control unit 32 is connected to the control valve 86, and the discharge tank 82 is discharged by the control valve 86 so that the resistance value of the discharge liquid in the discharge tank 82 is lower in the second discharge step S104 than in the first discharge step S102. It is configured to adjust the concentration of the electrolyte contained in the liquid. Since the other configurations are the same as those of the first and second embodiments, the same components are designated by the same reference numerals as those in FIGS. 1 to 3, 5 and 6, and the description thereof will be omitted.

For example, as shown in FIG. 6 of the second embodiment, the control unit 32 adjusts the resistance value of the discharge liquid in the same manner as the resistance value of the first load 24 of the first embodiment to perform the first discharge step S102. Execute for a predetermined time. Further, the control unit 32 adjusts the resistance value of the discharge liquid in the same manner as the resistance value of the second load 26 of the first embodiment, and executes the second discharge step S104 for a predetermined time. Even when one discharge tank 82 is used in this way, the resistance value is continuously lowered at the time of switching from the first discharge step S102 to the second discharge step S104 by adjusting the concentration of the electrolyte of the discharge liquid. Can be done. Therefore, since the discharge of the lithium ion battery 18 is not interrupted, the voltage of the lithium ion battery 18 does not rise again. This prevents the current value from becoming excessively large.

Note that FIG. 6 shows an example in which the resistance value of the variable resistance load 42 is adjusted in the first discharge step S102 in the same manner as the resistance value of the first load 24 of the first embodiment. In the first discharge step S102, the concentration of the electrolytic solution of the discharge liquid may be adjusted so that the resistance value continuously decreases. By doing so, the time required for discharging in the first discharging step S102 can be shortened. Further, in the first discharge step S102 and / or the second discharge step S104, the concentration of the electrolytic solution of the discharge liquid may be adjusted in still another embodiment.

Further, the discharge device 60 of the fourth embodiment includes a first discharge device 62 and a second discharge device 64, and the discharge device 70 of the fifth embodiment includes a first discharge tank 72 and a second discharge tank 74. , The discharge device may be configured by combining these. For example, the discharge device may be configured to include a first discharge device 62 and a second discharge tank 74. Further, the discharge device may be configured to include a first discharge tank 72 and a second discharge device 64. Further, the discharge device 40 of the second embodiment or the discharge tank 80 of the sixth embodiment may be used in the first discharge step S102, and the second discharge device 64 or the second discharge tank 74 may be used in the second discharge step S104. ..

Further, FIGS. 2, 5, 7, and 8 of the first to fourth embodiments show an example in which each discharge device performs discharge processing of one lithium ion battery 18, but each discharge device has a plurality of discharge devices. The discharge process of the lithium ion battery 18 may be performed at the same time. For example, a plurality of lithium ion batteries depicted in FIGS. 2, 5, 7, and 8 may be installed in parallel in each discharge device. In this case, a first load, a second load, a switch, a voltmeter, and a variable load of each discharge device are commonly used for discharging a plurality of batteries. Further, each discharge device may be provided with the same number of first load, second load, switch, voltmeter, and variable load as the number of batteries to be discharged at the same time. Further, each discharge device is provided with a plurality of first load, second load, switch, voltmeter, and variable load, which are smaller than the number of batteries to be discharged at the same time, and each first load and second load are provided. Loads, switches, voltmeters, and variable loads may be commonly used for discharging multiple batteries out of all batteries that are simultaneously discharged.

Further, in the first to sixth embodiments, the positive electrode active material portion and the negative electrode active material portion of the lithium ion battery 18 are in a semi-solid state containing an electrolytic solution, but the lithium ion battery 18 may be an all-solid lithium ion battery. good. In the unit cell of an all-solid-state lithium-ion battery, a solid electrolyte section is installed between the positive electrode active material section and the negative electrode active material section instead of the separator. The solid electrolyte portion is composed of a sulfide-based solid electrolyte or an oxide-based solid electrolyte that contains lithium and has high conductivity. The positive electrode current collector is, for example, aluminum foil, and the negative electrode current collector is, for example, copper foil. Further, the positive electrode active material portion and the negative electrode active material portion are in a solid state in which particles of a solid electrolyte are mixed instead of the electrolytic solution. The positive electrode active material portion and the negative electrode active material portion may contain the above-mentioned conductive auxiliary agent. Further, the positive electrode active material portion and the negative electrode active material portion may be configured not to contain particles of the solid electrolyte. Particles of the positive electrode active material can be obtained by crushing the positive electrode active material portion of the all-solid-state lithium-ion battery. When the particles of the positive electrode current collector are mixed, the particles of the positive electrode active material can be selected by sieving treatment or the like. The same applies to the negative electrode active material.

Further, although the lithium ion battery 18 is a laminated type in the first to sixth embodiments, the lithium ion battery 18 may be a non-bipolar laminated type or a bipolar laminated type. Further, the lithium ion battery 18 may be composed of only one unit cell. Further, the electrode structure may be a winding type. Further, the shape of the outer container may be square or cylindrical. Further, the outer container may be a metal can.

INDUSTRIAL APPLICABILITY The present invention can be used for recycling lithium contained in a lithium ion battery.

10 Lithium-ion battery recycling equipment 12, 40, 50, 60, 70, 80 Discharging device 14 Dismantling device 16 Recovery device 18 Lithium-ion battery 20 Positive electrode 22 Negative negative 24 First load 26 Second load 28, 52 Switch 30 Voltage Total 32 Control unit 42 Variable resistance load 62 1st discharge device 64 2nd discharge device 72 1st discharge tank 74 2nd discharge tank 82 Discharge tank 84 Electrolyte liquid supply unit 86 Control valve S102 1st discharge process S104 2nd discharge process S106 Disassembly process S108 Recovery process

Claims (8)

The first discharge step of discharging the lithium ion battery through the load in the first resistance value range to increase the amount of lithium contained in the positive electrode active material, and the first discharge step.
A second discharge step of further discharging the lithium ion battery through a load in the second resistance value range lower than the first resistance value range to further increase the amount of lithium contained in the positive electrode active material.
A method for recycling a lithium ion battery, comprising a recovery step of recovering the positive electrode active material from the lithium ion battery after the second discharge step. In claim 1,
Lithium ion in which the first load of the first resistance value is used in the first discharge step, and the second load of the second resistance value lower than the first resistance value is used in the second discharge step. How to recycle batteries. In claim 2,
Lithium that discharges the lithium ion battery in a state where both the first load and the second load are connected to the lithium ion battery in parallel at the time of switching from the first discharge step to the second discharge step. How to recycle ion batteries. In claim 1,
The load is a variable resistance load, and a method for recycling a lithium ion battery in which the resistance value of the variable resistance load is adjusted to be lower in the second discharge step than in the first discharge step. A first discharge step of discharging a lithium ion battery through a load in the first resistance value range to increase the amount of lithium contained in the positive electrode active material, and a second resistance lower than the first resistance value range. A discharge device capable of performing a second discharge step of further discharging the lithium ion battery through a load in the value range to further increase the amount of lithium contained in the positive electrode active material.
A lithium ion battery recycling facility including a recovery device for recovering the positive electrode active material from the lithium ion battery. In claim 5,
The discharge device has a first load having a first resistance value for the first discharge step and a second load having a second resistance value lower than the first resistance value for the second discharge step. With a load of, and equipped with a lithium-ion battery recycling facility. In claim 6,
The discharge device has the lithium ion in a state where both the first load and the second load are connected in parallel to the lithium ion battery at the time of switching from the first discharge step to the second discharge step. Lithium-ion battery recycling facility configured to discharge batteries. In claim 5,
The load is a variable resistance load, and the discharge device has a control unit configured to adjust the variable resistance load so that the resistance value is lower in the second discharge step than in the first discharge step. Equipped with lithium-ion battery recycling equipment.

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