JP2024043461A - Recycling system, recycling method, electrode manufacturing method, and battery manufacturing method - Google Patents

Abstract

To provide a recycling system and a recycling method capable of collecting reusable niobium titanium oxide from an electrode containing niobium titanium oxide, and to provide a method of manufacturing an electrode and a method of manufacturing a battery that use niobium titanium oxide collected by the system or method.SOLUTION: There is provided a recycling system 100 that includes: a water dispersion device 1 that disperses an electrode containing niobium titanium oxide in water; a solid-liquid separation device 2 that separates niobium titanium oxide from the electrode dispersed in water; and a first heat treatment device 3 that performs heat treatment of the separated niobium titanium oxide.SELECTED DRAWING: Figure 1

Description

Embodiments relate to a recycling system, a recycling method, an electrode manufacturing method, and a battery manufacturing method.

In lithium ion secondary batteries, a lithium-containing metal oxide is used as the positive electrode active material, and carbon is mainly used as the negative electrode. There is little research into recycling the negative electrode, and research and development is mainly focused on recycling the positive electrode.

By the way, the development of secondary batteries equipped with negative electrodes containing niobium titanium oxide is underway, and in order to increase the recycling rate of these secondary batteries, there is a need to realize the recycling of negative electrodes containing niobium titanium oxide.

International Publication No. WO2020/090690 JP 2019-130474 A

The problems to be solved are a recycling system and recycling method that can recover reusable niobium titanium oxide from electrodes containing niobium titanium oxide, and the production of electrodes using the niobium titanium oxide recovered by these systems or methods. An object of the present invention is to provide a method and a method for manufacturing a battery.

According to the embodiment, there is provided a water dispersion device for dispersing electrodes containing niobium titanium oxide in water, a solid-liquid separation device for separating niobium titanium oxide from the electrodes dispersed in water, and a step for heat-treating the separated niobium titanium oxide. 1. A recycling system is provided, including a heat treatment device.

Further, according to the embodiment, a step of dispersing an electrode containing niobium titanium oxide in water, a step of separating niobium titanium oxide from the electrode dispersed in water, and a step of performing a first heat treatment on the separated niobium titanium oxide A recycling method is provided, including.

Furthermore, according to another embodiment, a step of subjecting a battery including a positive electrode and a negative electrode containing niobium titanium oxide to a third heat treatment;
a step of treating the battery with an acidic solvent;
separating niobium titanium oxide from a battery treated with an acidic solvent;
and subjecting the separated niobium titanium oxide to a first heat treatment.

Further, according to another embodiment, a third heat treatment device that performs a third heat treatment on a battery including a positive electrode and a negative electrode containing niobium titanium oxide;
an acid treatment device for treating the battery subjected to the third heat treatment with an acidic solvent;
a solid-liquid separator that separates niobium titanium oxide from batteries treated with an acidic solvent;
and a first heat treatment device that performs a first heat treatment on the separated niobium titanium oxide.

According to another embodiment, a method for manufacturing an electrode is provided, in which the electrode is manufactured using niobium titanium oxide recovered by the recycling method according to the embodiment.

Further, according to another embodiment, a method for manufacturing a battery is provided, including a step of manufacturing an electrode using niobium titanium oxide recovered by the recycling method according to the embodiment, and a step of manufacturing a battery including the electrode. Ru.

FIG. 1 is a schematic diagram showing an example of a recycling system according to a first embodiment. 2 is a flowchart showing an example of a recycling method using the recycling system of FIG. 1. FIG. The schematic diagram showing another example of the recycling system of a 1st embodiment. 4 is a flowchart showing an example of a recycling method using the recycling system of FIG. 3. A schematic diagram showing an example of a recycling system according to a second embodiment. 6 is a flowchart showing an example of a recycling method using the recycling system of FIG. 5. FIG. 7 is a schematic diagram showing another example of the recycling system of the second embodiment. 8 is a flowchart showing an example of a recycling method using the recycling system of FIG. 7. FIG. 2 is a partially cutaway perspective view showing an example of a battery that is subjected to a recycling process of the system or method according to an embodiment. FIG. 9 is an enlarged sectional view of section A in FIG. 9; The schematic diagram which shows yet another example of the recycling system of 2nd Embodiment. 12 is a flowchart showing an example of a recycling method using the recycling system of FIG. 11 .

(First embodiment)
A recycling system and recycling method according to a first embodiment will be described below with reference to the drawings. In the first embodiment, niobium titanium oxide is recovered and regenerated from an electrode containing niobium titanium oxide. The electrode containing niobium titanium oxide is not limited to one that has been used and then disposed of, but may also be one that has been kept unused or disposed of due to circumstances such as non-standardization. That is, the state of use of the electrode does not matter. The electrode is also called a treated electrode.

FIG. 1 schematically shows an example of a recycling system for recovering niobium titanium oxide from an electrode (electrode to be treated) containing niobium titanium oxide. The recycling system 100 includes a water dispersion device 1 , a solid-liquid separation device 2 disposed downstream of the water dispersion device 1 , and a first heat treatment device 3 disposed downstream of the solid-liquid separation device 2 . The object to be treated is transported to a water dispersion device 1, a solid-liquid separation device 2, and a first heat treatment device 3 in this order by a conveyor, a slurry pump (not shown), or the like. Therefore, the recycling system 100 may include a conveyor that conveys the object to be treated.

The water dispersion device 1 is for dispersing an electrode containing niobium titanium oxide (hereinafter referred to as a TNO electrode) in water. When a TNO electrode is immersed in water, it can be separated into a current collector and other components, and dispersed in water. This water dispersion tends to occur when the TNO electrode contains a water-soluble or water-dispersible binder. Niobium titanium oxide does not easily deteriorate when it comes into contact with water. Therefore, by dispersing the TNO electrode in water, the TNO electrode can be disassembled without damaging the niobium titanium oxide. The water dispersion device 1 is not particularly limited as long as it includes a container capable of containing water for dispersing the TNO electrode. For example, a mixing tank equipped with a stirring blade may be used. To facilitate the dismantling of the TNO electrode, the water dispersion device 1 can be equipped with a pulverizer for pulverizing the TNO electrode.

A slurry in which TNO electrodes are dispersed in water is supplied to the solid-liquid separator 2 from the water dispersion device 1 . The solid-liquid separator 2 is for separating a current collector and niobium titanium oxide into solid-liquid from a slurry in which TNO electrodes are dispersed in water. Niobium titanium oxide has a higher density than other materials constituting the electrode, so it is suitable for separation using density differences. Further, since the current collector foil made of aluminum or the like is larger than the niobium titanium oxide, the size can be used for separation. Examples of the solid-liquid separator 2 include a sedimentation separator, a cyclone, and a sieve.

The first heat treatment device 3 heat-treats the niobium titanium oxide separated by the solid-liquid separator 2. Examples of the heat treatment apparatus include a furnace, a rotary kiln, and the like.

A recycling method using the recycling system 100 described above will be described with reference to FIG. 2. The recycling method shown in FIG. 2 includes a water dispersion step S1, a solid-liquid separation step S2, and a first heat treatment step S3.
(Water dispersion step S1)
The TNO electrode is supplied to the water dispersion device 1 and is immersed in water in the water dispersion device 1. As a result, the TNO electrode is dispersed in water and separated into a metal piece such as a current collector and an electrode material containing niobium titanium oxide. The TNO electrode is sent to the next step S2 in a state where it is dispersed in water. Here, as the solvent for dispersion, an aqueous liquid such as a mixed liquid of water and an organic substance may be used instead of water. Examples of organic substances include at least one selected from the group consisting of alcohol (for example, ethanol), acetonitrile, and acetone.
(Solid-liquid separation step S2)
For example, a sedimentation separator is used to remove metal debris from a slurry in which TNO electrodes are dispersed in water. By means of sedimentation separation, it is also possible to remove materials having a lower density than niobium titanium oxide (for example, carbon materials). After removal, the slurry is sieved to remove foreign matter. Next, the niobium titanium oxide is separated from the slurry using a cyclone. By washing the separated niobium titanium oxide with water, residual ions (for example, salts such as electrolytes (salts containing P or F)) and water-soluble materials (for example, water-soluble binders) are removed. The water-washed niobium titanium oxide is transported to the next step S3.
(First heat treatment step S3)
A first heat treatment is performed on the water-washed niobium titanium oxide. As a result, the capacity of the niobium titanium oxide can be recovered, so that the niobium titanium oxide can be reused. Furthermore, if a carbon material is attached to the surface of the particles of niobium titanium oxide, this carbon material can be removed by the first heat treatment. The first heat treatment can be performed in the atmosphere at a temperature of 600° C. or more and 1200° C. or less for 24 hours or less. A more preferable range of treatment time is 1 hour or more and 24 hours or less. If the treatment temperature is low or the treatment time is short, it becomes difficult to sufficiently recover the capacity of the niobium titanium oxide. On the other hand, if the treatment temperature is high or the treatment time is long, the niobium titanium oxide may cause excessive grain growth and the characteristics may deteriorate.

In order to adjust the particle size of the niobium titanium oxide that has been subjected to the first heat treatment, the niobium titanium oxide may be crushed.

According to the recycling system and recycling method described above, reusable niobium titanium oxide can be recovered from the electrode.

Next, another example of the recycling system and recycling method of the first embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 schematically shows another example of a recycling system for recovering niobium titanium oxide from an electrode containing niobium titanium oxide. FIG. 4 is a flowchart of a recycling method using the recycling system shown in FIG.

The recycling system 101 shown in FIG. 3 has the same configuration as the recycling system 100 shown in FIG. 1 except that the second heat treatment device 4 is disposed upstream of the water dispersion device 1 of the recycling system 100 shown in FIG.

The second heat treatment device 4 will be described. The second heat treatment device 4 applies heat treatment to the TNO electrode. This makes it possible to remove organic matter from the TNO electrode. The organic matter is, for example, an organic solvent, a carbon material, a binder, etc. If the binder is water-soluble or water-dispersible, the binder can be removed by dissolving or dispersing it in water in the water dispersion step S1, so that the second heat treatment device 4 can be omitted. Examples of the second heat treatment device 4 include a furnace, a rotary kiln, etc.

A recycling method using the recycling system shown in FIG. 3 will be explained with reference to FIG. 4. The recycling method shown in FIG. 4 is performed in the same manner as the recycling method shown in FIG. 2, except that the second heat treatment step S4 is performed before the water dispersion step S1.

The second heat treatment step S4 can be performed, for example, in the atmosphere. The heat treatment temperature can be in the range of 300°C or higher and 900°C or lower. Preferably, the temperature is 400°C to 600°C. This is because by carrying out the process at a temperature below the melting point of the aluminum used as the current collector, the size of the aluminum pieces can be increased, making it easier to separate them in subsequent steps. Further, the processing time can be set in a range of 15 minutes or more and 6 hours or less. If the heat treatment temperature is low or the heat treatment time is short, organic substances may not be removed from the TNO electrode and may remain. On the other hand, if the heat treatment temperature is high or the heat treatment time is long, the metal material such as the current collector may melt, making it difficult to separate the metal material and the niobium titanium oxide.

After cooling the niobium titanium oxide that has been subjected to the second heat treatment, it is desirable to perform a water dispersion step S1 on the cooled niobium titanium oxide. Thereby, in the water dispersion step S1, it is possible to prevent bumping and generation of a large amount of steam due to a sudden increase in the temperature of the water. As a result, problems such as powder flying up can be avoided, making it possible to perform work more safely. It is desirable to cool the niobium titanium oxide to, for example, 100° C. or lower.

The water dispersion step S1 and subsequent steps can be performed in the same manner as the recycling method shown in FIG. 2.

According to the recycling system and recycling method described above, it becomes possible to recover reusable niobium titanium oxide from the electrode.

Although the electrode to be recycled is not particularly limited as long as it contains niobium titanium oxide, one example will be described below.

The electrode can include a current collector and an active material-containing layer. The active material-containing layer may be laminated or formed on one or both sides of the current collector. The active material-containing layer can include an active material and optionally a conductive agent and a binder.

The active material includes niobium titanium oxide. An example of niobium titanium oxide is monoclinic niobium titanium oxide. Monoclinic niobium titanium oxide is characterized by having a highly stable crystal structure, excellent resistance to water, acids and alkalis, and high density. An example of monoclinic niobium titanium oxide is a compound represented by Li _x Ti _1-y M1 _y Nb _2-z M2 _z O _7+δ . Here, M1 is at least one selected from the group consisting of Zr, Si, and Sn. M2 is at least one selected from the group consisting of V, Ta, and Bi. The respective subscripts in the composition formula are 0≦x≦5, 0≦y<1, 0≦z<2, and −0.3≦δ≦0.3. A specific example of the monoclinic niobium titanium oxide is Li _x Nb ₂ TiO ₇ (0≦x≦5). The density of Li _x Nb ₂ TiO ₇ (0≦x≦5) is 4.34 g/cm ³ .

Another example of the monoclinic niobium titanium oxide is a compound represented by Li _x Ti _1-y M3 _y+z Nb _2-z O _7-δ , where M3 is at least one selected from Mg, Fe, Ni, Co, W, Ta, and Mo. The subscripts in the composition formula are 0≦x≦5, 0≦y<1, 0≦z<2, and −0.3≦δ≦0.3.

Niobium titanium oxide may contain inevitable impurities. Examples of unavoidable impurities include K, Na, Si, and P.

Niobium titanium oxide may contain lithium ions.

Niobium titanium oxide can be in the form of particles.

The conductive agent is blended to improve current collection performance and suppress contact resistance between the active material and the current collector. Examples of conductive agents include vapor grown carbon fibers (VGCF), carbon nanotubes, carbon blacks such as acetylene black, and carbonaceous materials such as graphite. One of these may be used as a conductive agent, or a combination of two or more may be used as a conductive agent. Alternatively, instead of using a conductive agent, the surface of the active material particles may be coated with carbon or an electronically conductive inorganic material.

The binder can fill gaps between the active materials and bind the active materials and the current collector. Examples of binders include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorine rubber, styrene butadiene rubber, polyacrylic acid compounds, imide compounds, carboxymethyl cellulose. ; CMC), and salts of CMC. One of these may be used as a binder, or a combination of two or more may be used as a binder. When a water-soluble or water-dispersed binder such as an emulsion is used, TNO can be recovered according to the flow shown in FIG. 2.

As an example, the active material, conductive agent, and binder in the active material-containing layer may be mixed in proportions of 68% by mass or more and 96% by mass or less, 2% by mass or more and 30% by mass or less, and 2% by mass or more and 30% by mass or less, respectively.

For the current collector, a material is used that is electrochemically stable at a potential at which lithium (Li) is inserted into and removed from the active material. Examples of the current collector are copper, nickel, stainless steel, aluminum, and aluminum alloy. The thickness of the current collector is, for example, 5 μm or more and 20 μm or less.

Further, the current collector can include a portion on the surface of which no active material-containing layer is formed. This part acts as a current collection tab.

The recycling system of the first embodiment described above includes a water dispersion device that disperses electrodes containing niobium titanium oxide (electrodes to be treated) in water, and a solid-liquid separation device that separates niobium titanium oxide from the electrodes dispersed in water. and a first heat treatment device for heat treating the separated niobium titanium oxide. Further, according to the recycling method of the first embodiment, the steps of dispersing the electrode containing niobium titanium oxide (electrode to be treated) in water, separating the niobium titanium oxide from the electrode dispersed in water, and separating the niobium titanium oxide from the electrode dispersed in water are performed. and a step of subjecting the niobium titanium oxide to a first heat treatment. Therefore, according to the first embodiment, reusable niobium titanium oxide can be recovered from the electrode.
(Second embodiment)
A recycling system and recycling method according to a second embodiment will be described below with reference to the drawings. In the second embodiment, niobium titanium oxide is recovered and regenerated from a battery including an electrode (electrode to be treated) containing niobium titanium oxide as a negative electrode. The battery is not limited to one that has been used and disposed of, but may also be one that has been stored unused or disposed of due to circumstances such as non-standardization. In other words, the state of use of the battery does not matter. The battery is also called a battery to be treated.

Figure 5 shows an outline of an example of a recycling system for recovering niobium titanium oxide from treated batteries. The recycling system 102 shown in Figure 5 has a similar configuration to the recycling system 100 shown in Figure 1, except that it is equipped with a discharge treatment device 5 upstream of the water dispersion device 1 of the recycling system 100 shown in Figure 1, and a separation device arranged downstream of the discharge treatment device 5. The separation device includes an exterior separation device 6, a positive and negative electrode separation device 7 arranged downstream of the exterior separation device 6, and a chamber 8 in which the exterior separation device 6 and the positive and negative electrode separation device 7 are housed. The recycling system 102 and a recycling method using the recycling system 102 will be described with reference to Figures 5 and 6.

A discharge treatment S5 is performed on the battery to be treated using the discharge treatment device 5. The discharge treatment device 5 is not particularly limited as long as it can discharge the battery. Examples of the discharge processing device 5 include a charging/discharging device, a resistor, and the like. If the battery still has usable remaining capacity, there is a risk that it will self-discharge or short-circuit, causing a spark to fly and ignite. Therefore, it is necessary to sufficiently discharge the battery through the positive and negative electrodes so that no usable residual capacity remains. Specifically, the battery is discharged by connecting the battery to a charging/discharging device or by attaching an appropriate resistor to the battery. It is desirable to discharge the battery sufficiently until the voltage falls below the voltage at which the battery has no usable remaining capacity. The battery that has been subjected to the discharge treatment S5 by the discharge treatment device 5 is sent to the exterior separation device 6 for exterior separation S6.

The exterior separation device 6 is housed in the chamber 8 together with the positive and negative electrode separation device 7 . The inside of the chamber 8 is preferably a low oxygen atmosphere such as a nitrogen atmosphere. This prevents the electrolyte and the like from coming into contact with air when the battery is disassembled, making work safer. The exterior separation device 6 is for opening the exterior member of the battery by cutting or the like, and taking out the electrode group inside the exterior member to the outside. As the exterior separation device 6, for example, a cutter, cutter, cutter, etc. can be used. The electrode group taken out from the battery by the exterior separation S6 using the exterior separation device 6 is transported to the positive and negative electrode separation device 7 in order to perform positive and negative electrode separation S7.

The positive and negative electrode separation device 7 is for separating the electrode group into a positive electrode, a separator, and a negative electrode. The electrode group can be obtained as a stacked body in which a positive electrode and a negative electrode are laminated with a separator interposed therebetween, such as a positive electrode, a separator, a negative electrode, a separator, and a positive electrode, or a wound body in which the positive electrode, separator, and negative electrode are wound. For example, in the case of an electrode group using continuous separators, a device having a mechanism for winding up the separators is used as the positive and negative electrode separation device 7. In this way, a positive electrode and a negative electrode can be separated on the front and back sides of the separator. By separating the positive and negative electrodes in advance in this manner, the members constituting the positive and negative electrodes do not mix, and can be effectively recycled. The negative electrode taken out from the electrode group by the positive and negative electrode separation device 7 is transported to the water dispersion device 1. The negative electrode may be crushed before being supplied to the water dispersion device 1. Thereby, dispersion of the negative electrode into water can be promoted. The positive electrode taken out from the electrode group by the positive and negative electrode separator 7 is subjected to recycling treatment separately from the negative electrode.

The negative electrode supplied to the water dispersion device 1 is subjected to the same treatment as in the first embodiment described with reference to FIGS. 1 and 2. Note that the separation device may be divided into the exterior separation device 6 and the positive and negative electrode separation device 7 as described above, but it may also be a device that combines the two functions of exterior separation and positive and negative electrode separation.

The recycling system and recycling method described above make it possible to safely recover reusable niobium titanium oxide from batteries.

The second embodiment is not limited to the forms shown in FIGS. 5 and 6, but may be, for example, the forms shown in FIGS. 7 and 8. FIG. 7 schematically shows an example of a recycling system for recovering niobium titanium oxide from a battery to be treated. Further, FIG. 8 shows a flowchart of the recycling method shown in FIG. 7.

The recycling system 103 shown in FIG. 7 includes a discharge treatment device 5 disposed upstream of the water dispersion device 1 of the recycling system 101 shown in FIG. 3, an exterior separation device 6 disposed downstream of the discharge treatment device 5, and an exterior It has the same configuration as the recycling system 101 except that it includes a positive and negative electrode separation device 7 arranged downstream of the separation device 6, and a chamber 8 in which the exterior separation device 6 and the positive and negative electrode separation device 7 are accommodated.

Therefore, the recycling system 103 shown in FIG. 7 and the recycling method shown in FIG. 8 make it possible to safely recover reusable niobium titanium oxide from batteries.

The batteries to be recycled are not particularly limited as long as they contain electrodes containing niobium titanium oxide. Examples of batteries include batteries with aqueous electrolytes and batteries with non-aqueous electrolytes. In addition, the batteries may be single batteries (single cells), assembled batteries, or battery packs.

An example of a battery (secondary battery) will be described with reference to FIGS. 9 and 10. FIG. 9 is a partially cutaway perspective view showing a non-aqueous electrolyte secondary battery, which is an example of a battery. FIG. 10 is an enlarged sectional view of section A of the non-aqueous electrolyte secondary battery shown in FIG. As shown in FIG. 9, the nonaqueous electrolyte battery 20 includes a rectangular cylindrical metal container 21 with a bottom, a flat electrode group 22, a metal sealing plate 23, a negative terminal 24, and a positive terminal 25. include. A flat electrode group 22 is housed in a metal container 21 . The flat electrode group 22 includes a negative electrode 26, a positive electrode 27, and a separator 28. The electrode group 22 has a structure in which a negative electrode 26 and a positive electrode 27 are spirally wound into a flat shape with a separator 28 interposed therebetween. Although a wound type electrode group will be described here, the electrode group may be a laminated type electrode group in which a plurality of negative electrodes 26, separators 28, and positive electrodes 27 are laminated. As shown in FIG. 10, the negative electrode 26 includes a negative electrode current collector 26a and a negative electrode active material-containing layer 26b supported on the negative electrode current collector 26a. As shown in FIG. 10, the positive electrode 27 includes a positive electrode current collector 27a and a positive electrode active material-containing layer 27b supported on the positive electrode current collector 27a. The electrode group 22 holds an electrolyte (not shown). The opening of the metal container 21 is sealed with a metal sealing plate 23. The metal container 21 and the sealing plate 23 constitute an exterior member.

As shown in FIG. 9, the metal sealing plate 23 is provided with a negative electrode terminal 24. A negative electrode current collector tab 29 is electrically connected to the negative electrode terminal 24. The negative electrode current collector tab 29 is electrically connected to the negative electrode current collector 26a of the negative electrode 26. The positive electrode terminal 25 is fixed to the metal sealing plate 23 via an insulating member 30. A positive electrode current collector tab 31 is electrically connected to the positive electrode terminal 25. The positive electrode current collector tab 31 is electrically connected to the positive electrode current collector 27a of the positive electrode 27.

An example of the negative electrode 26 is the TNO electrode described in the first embodiment. The positive electrode active material contained in the positive electrode 27 includes, for example, Li or a compound capable of intercalating and deintercalating Li ions. Furthermore, the positive electrode current collector 27a may include, for example, metal foil.

For the separator 28, for example, a porous film, a synthetic resin nonwoven fabric, a solid electrolyte layer, etc. can be used.

For example, an aqueous electrolyte, a non-aqueous electrolyte, etc. can be used as the electrolyte. Non-aqueous electrolytes are prepared, for example, by dissolving electrolyte salts such as lithium salts in organic solvents. Aqueous electrolytes are prepared, for example, by dissolving electrolyte salts such as lithium salts in aqueous solvents. Examples of electrolyte salts include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroarsenate (LiAsF ₆ ), and trifluoromethane. Lithium salts such as lithium sulfonate (LiCF ₃ SO ₃ ) and lithium bistrifluoromethylsulfonylimide (LiN(CF ₃ SO ₂ ) ₂ ) may be mentioned.

The exterior member illustrated in FIGS. 9 and 10 is made of metal, but is not limited to this. For example, a laminate film or the like may be used as the exterior member. Further, the shape of the exterior member is not particularly limited. The shape of the exterior member may be, for example, flat (thin), square, cylindrical, coin, button, or the like. The exterior member can be appropriately selected depending on the battery dimensions and the intended use of the battery.

The recycling system and recycling method of the second embodiment described above recovers niobium titanium oxide from the electrode according to the first embodiment after separating the electrode from the battery. It can be recovered from.

Still another example of the second embodiment will be described with reference to FIGS. 11 and 12. FIG. 11 schematically shows an example of a recycling system for recovering niobium titanium oxide from a battery to be treated. The recycling system 104 shown in FIG. 11 includes a discharge treatment device 5, a third heat treatment device 10, a crushing device 11, an acid treatment device 12, and a solid-liquid separation device arranged downstream of the discharge treatment device 5 in the following order. 2. A first heat treatment device 3 is provided. The objects to be treated are transported through the discharge treatment device 5, the third heat treatment device 10, the pulverization device 11, the acid treatment device 12, the solid-liquid separation device 2, and the first heat treatment device 3 in this order by a conveyor, a slurry pump (not shown), or the like. transported to. Therefore, the recycling system 104 may include a conveyor for conveying the object to be treated. FIG. 12 shows an example of the flow of a recycling method using the recycling system 104.
(Discharge treatment step S10)
A discharge treatment S10 is performed on the battery to be treated using the discharge treatment apparatus 5. The discharge treatment device 5 and the discharge treatment S10 are as described in the first embodiment. The battery that has been subjected to the discharge treatment S10 by the discharge treatment apparatus 5 is sent to the third heat treatment apparatus 10 for third heat treatment S11.
(Third heat treatment step S11)
Before performing the third heat treatment S11, packaging separation S6 may be performed using the packaging separation device 6. The exterior separation device 6 and exterior separation S6 are as described in the first embodiment.

The third heat treatment apparatus 10 will be explained. The third heat treatment device 10 heat-treats the battery that has been subjected to the discharge treatment S10. The battery may or may not have an exterior member. The third heat treatment allows organic substances to be removed from the battery to be treated. Examples of the organic substance include an organic solvent, a carbon material, and a binder. As a result, it is possible to avoid environmental pollution and danger caused by organic substances, and to promote separation of the current collector from the positive electrode and the negative electrode. Examples of the third heat treatment apparatus 10 include a furnace, a rotary kiln, and the like.

The third heat treatment step S11 can be performed, for example, in the atmosphere. The heat treatment temperature can be in the range of 300°C or higher and 900°C or lower. Preferably, the temperature is 400°C to 600°C. This is because by carrying out the process at a temperature below the melting point of the aluminum used as the current collector, the size of the aluminum pieces can be increased, making it easier to separate them in subsequent steps. Further, the processing time can be set in a range of 15 minutes or more and 6 hours or less. If the heat treatment temperature is low or the heat treatment time is short, organic substances may remain without being removed from the battery to be treated. On the other hand, if the heat treatment temperature is high or the heat treatment time is long, the metal material such as the current collector may melt, making it difficult to separate the metal material and the niobium titanium oxide.

After the third heat treatment S11, the battery to be treated may be cooled if necessary. Examples of cooling include air cooling and water cooling.
(Crushing process S12)
It is desirable to perform pulverization S12 on the battery to be treated that has been subjected to the third heat treatment. Thereby, in the acid treatment S13 performed in the subsequent step, it is possible to promote dissolution of the positive electrode in the acidic solvent. As a result, the positive electrode can be easily removed from the battery to be treated. Although the crushing device 11 is not particularly limited, for example, a crusher using shear stress (for example, a hammer mill) can be used. Note that the pulverization S12 may be omitted.
(Acid treatment step S13)
An acid treatment S13 is performed on the battery to be treated which has been subjected to the crushing step S12 as necessary. Examples of the acid treatment include immersing the battery to be treated in an acidic solvent, shaking the battery to be treated in the acidic solvent, and subjecting the battery to be treated to ultrasonic treatment in an acidic solvent. Each process may be performed alone or a plurality of processes may be combined. When a battery to be treated is subjected to an acid treatment, metal materials such as a current collector and a terminal (for example, Al, Al alloy) and a positive electrode active material are dissolved in an acidic solvent. On the other hand, niobium titanium oxide has high acid resistance and therefore does not dissolve in acidic solvents. As a result, most of the battery to be treated is dissolved in the acidic solvent and removed, a solid mainly composed of niobium titanium oxide is dispersed in the acidic solvent, and a portion of the solid is precipitated in the acidic solvent. Note that the positive electrode active material dissolved in the acidic solvent can be regenerated through a separate recycling process.
The acidic solvent can be, for example, an aqueous solution containing at least one of nitric acid or sulfuric acid. Thereby, dissolution of the positive electrode active material and the metal material in the acidic solvent can be promoted. The pH of the solution can be set to 1 or less (but not including 0).

The acid treatment can be carried out while maintaining the temperature of the acidic solvent at room temperature or higher. This can promote dissolution of the positive electrode active material and the metal material in the acidic solvent. However, if the temperature of the acidic solvent is too high, there is a risk that water will evaporate due to the aqueous solution. In addition, there is a risk that niobium titanium oxide will dissolve in the acidic solvent. Therefore, the more preferable temperature range for the acid treatment is from room temperature to 50°C.

The acid treatment device 12 used for the acid treatment is not particularly limited as long as it is equipped with a container capable of containing an acidic solvent for dispersing the treated batteries. For example, a mixing tank equipped with an agitator may be used. In order to facilitate dismantling of the treated batteries, the acid treatment device 12 may be equipped with a pulverizer for pulverizing the treated batteries. The acid treatment may also be performed while applying ultrasound to the treated batteries.

Solid-liquid separation S14 is performed by the solid-liquid separator 2 on the acidic solvent in which a solid mainly composed of niobium titanium oxide is dispersed. The niobium titanium oxide may be washed with water before solid-liquid separation S14. This allows the remaining acidic solvent and the like to be removed.
(Solid-liquid separation step S14)
Niobium titanium oxide is recovered by solid-liquid separation from an acidic solvent in which a solid mainly composed of niobium titanium oxide is dispersed. Examples of solid-liquid separation include sedimentation, centrifugation, filtration, and sieving. Niobium titanium oxide has a higher density than other materials constituting the electrode, so it is suitable for separation using density differences. Examples of this separation include sedimentation and centrifugation.

The solid-liquid separator 2 is supplied with an acidic solvent in which a solid mainly composed of niobium titanium oxide is dispersed from the acid treatment device 12 . The solid-liquid separator 2 is for separating niobium titanium oxide from the acidic solvent into solid-liquid. Examples of the solid-liquid separator 2 include a sedimentation separator, a cyclone, and a sieve.

For example, a sedimentation separator is used to remove metal pieces from an acidic solvent in which solids mainly composed of niobium titanium oxide are dispersed. By means of sedimentation separation, it is also possible to remove materials having a lower density than niobium titanium oxide (for example, carbon materials). After removal, the acidic solvent is sieved to remove foreign substances. Next, the niobium titanium oxide is separated from the acidic solvent using a cyclone. Alternatively, when much of the positive electrode active material etc. is dissolved in the acidic solvent, the niobium titanium oxide can be separated from the acidic solvent using a cyclone without performing sedimentation and sieving.

The solid-liquid separated niobium titanium oxide may be washed with water. Thereby, remaining ions (for example, salts such as electrolytes (salts containing P or F)) can be removed.
After the separation, the niobium titanium oxide is washed with water if necessary and is transported to the next step S15.
(First heat treatment step S15)
In the first heat treatment step S15, first heat treatment is performed by the first heat treatment device 3. Examples of the first heat treatment apparatus include a furnace, a rotary kiln, and the like.

A first heat treatment is performed on the niobium titanium oxide. As a result, the capacity of the niobium titanium oxide can be recovered, so that the niobium titanium oxide can be reused. Further, if an acidic solvent remains on the surface of the particles of niobium titanium oxide, this acidic solvent can be removed by the first heat treatment. The first heat treatment can be performed in the atmosphere at a temperature of 600° C. or more and 1200° C. or less for 24 hours or less. A more preferable range of treatment time is 1 hour or more and 24 hours or less. If the treatment temperature is low or the treatment time is short, it becomes difficult to sufficiently recover the capacity of the niobium titanium oxide. On the other hand, if the treatment temperature is high or the treatment time is long, the niobium titanium oxide may cause excessive grain growth and the characteristics may deteriorate.

In order to adjust the particle size of the niobium titanium oxide that has been subjected to the first heat treatment, the niobium titanium oxide may be pulverized.

According to the recycling system and recycling method described above, it is possible to safely and easily recover reusable niobium titanium oxide from the battery to be treated without performing an operation of separating only the electrodes from the battery to be treated. .
(Third embodiment)
The third embodiment is a method for producing an electrode using the niobium titanium oxide recovered in the first or second embodiment.

The electrode manufacturing method consists of a step of preparing a slurry by dispersing niobium titanium oxide, a conductive agent, and a binder in a solvent, a step of applying the slurry to a current collector, and a step of drying the slurry applied to the current collector. The method includes a step of forming an active material-containing layer by doing this, and a step of pressing the current collector on which the active material-containing layer is formed. After drying, a step of cutting the current collector on which the active material-containing layer is formed may be performed, if necessary. Regarding the niobium titanium oxide, the conductive agent, the binder, and the current collector, the same ones as those described in the first embodiment can be used.

According to the third embodiment, since the electrode is manufactured using the niobium titanium oxide recovered in the first or second embodiment, it is possible to manufacture the electrode with a high recycling rate.
(Fourth embodiment)
The fourth embodiment relates to a method for manufacturing a battery. The method for manufacturing a battery includes a step of manufacturing an electrode group including the electrode manufactured in the third embodiment as a negative electrode, a step of housing the electrode group in an exterior member, and a step of causing the electrode group housed in the exterior member to retain an electrolyte. and a step of sealing the exterior member. The electrode group is produced, for example, by arranging a separator between a positive electrode and a negative electrode. The shape of the electrode group is not particularly limited, and for example, a positive electrode, a separator, and a negative electrode are stacked, a positive electrode, a separator, and a negative electrode are wound into a flat or cylindrical shape, and a positive electrode, a separator, and a negative electrode are formed into a 99. You can use something that is bent. Examples of the electrolyte include the same ones as those described in the second embodiment.

According to the fourth embodiment, since the electrode manufactured using the niobium titanium oxide recovered in the first or second embodiment is used, it is possible to manufacture a battery with a high recycling rate.

The battery manufactured by the method of the fourth embodiment may be used as an assembled battery or incorporated into a battery pack. The battery according to the embodiment is suitably used in applications that require excellent cycle performance when drawing a large current. Specifically, it can be used as a power source for a digital camera, or as a battery for a vehicle such as a two- or four-wheeled hybrid electric vehicle, a two- or four-wheeled electric vehicle, an assisted bicycle, a railway vehicle (for example, a train), or a stationary battery. Used as a battery. In particular, it is suitably used as an on-vehicle battery mounted on a vehicle.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the embodiments described below.
Example 1
Niobium titanium oxide was recycled from a battery (hereinafter referred to as a treated battery) having a TNO electrode as a negative electrode and a metal can as an exterior member, using the recycling system 103 shown in FIG. 7 and the procedure shown in FIG. 8.

The batteries to be treated that were incorporated in the waste module were separated and only the batteries to be treated were taken out. This taken out battery was set in a charging/discharging device as the discharge treatment device 5, and discharge treatment was performed at a current value of 1C. At this time, after reaching the discharge reference voltage of this battery of 1.5 V, additional discharge was performed for an additional 5 minutes. The battery subjected to this discharge treatment was set in an exterior separation device 6 installed in a chamber 8 set in a nitrogen atmosphere, and the exterior member (can) was cut to take out the electrode group. Further, this electrode group was applied to a positive and negative electrode separator 7 provided in a chamber 8 to separate it into a positive electrode, a separator, and a negative electrode.

The separated negative electrode was placed in a second heat treatment device 4 maintained at 600° C. to remove organic substances contained in the negative electrode. The heat treatment time was 60 minutes. After the powder containing niobium titanium oxide obtained here was cooled to 100° C. or lower, it was dispersed in water using a water dispersion device 1. Thereafter, it was put into a solid-liquid separator 2, large aluminum pieces were removed using a coarse mesh, and niobium titanium oxide was separated using a cyclone. Thereafter, ions remaining in the niobium titanium oxide were removed by washing with water. The niobium titanium oxide was represented by Nb ₂ TiO ₇ .

A portion of the niobium titanium oxide obtained here was taken, and 80% by mass of niobium titanium oxide was mixed with 10% by mass of acetylene black as a conductive agent and 10% by mass of CMC as a binder, and these were kneaded with a water solvent to prepare a slurry. The slurry was applied to an aluminum foil, and then dried and pressed to prepare an electrode. A coin-shaped cell was made using the obtained electrode, and the capacity of the niobium titanium oxide was confirmed to be 237 mAh/g.

The remaining niobium titanium oxide, a portion of which has been taken out as described above, is put into the first heat treatment device 3 and heat treated at 900°C for 30 minutes in the atmosphere to remove and reactivate the remaining organic matter. Regenerated niobium titanium oxide was obtained. A coin-shaped cell was produced using this regenerated niobium titanium oxide in the same manner as described above, and the capacity was confirmed to be 265 mAh/g, confirming that the capacity of the niobium titanium oxide had been recovered.
(Example 2-3)
Recycling treatment was carried out in the same manner as in Example 1, except that the temperature and time of the first heat treatment and the second heat treatment were changed as shown in Table 1. Further, when the capacity of the niobium titanium oxide was confirmed in the same manner as in Example 1, it was confirmed that the capacity was recovered by the first heat treatment as shown in Table 1.
(Example 4)
Using the recycling system 102 shown in FIG. 5, niobium titanium oxide was recycled for the battery to be treated that was incorporated into the waste module according to the procedure shown in FIG. 6.

Discharge treatment S5, exterior separation S6, and positive and negative electrode separation S7 were performed in the same manner as in Example 1.

The separated negative electrode was immersed in water using a water dispersion device 1 to separate the negative electrode into aluminum foil and electrode material. Next, in solid-liquid separation S2, large aluminum foils were removed using a sieve. Subsequently, in solid-liquid separation S2, large foreign substances (such as aluminum foil that could not be removed in the previous step) were removed from the slurry containing the electrode material using a coarse mesh, and then niobium titanium oxide was separated using a cyclone. Thereafter, the niobium titanium oxide was washed with water to remove remaining ions and water-soluble binder (CMC). The niobium titanium oxide was represented by Nb ₂ TiO ₇ . A part of the niobium titanium oxide obtained here was taken out, and 10 mass% of acetylene black as a conductive agent and 10 mass% of CMC as a binder were added to 80 mass% of niobium titanium oxide, and these were kneaded with a water solvent. A slurry was prepared. After applying the slurry onto an aluminum foil, it was dried and pressed to produce an electrode. A coin-shaped cell was produced using the obtained electrode, and the capacity of the niobium titanium oxide was confirmed to be 228 mAh/g. The niobium titanium oxide obtained here is put into the first heat treatment device 3 and subjected to a first heat treatment at 900°C for 30 minutes in the atmosphere to remove remaining organic matter and reactivate it, thereby producing recycled niobium titanium oxide. Obtained. When the capacity of this regenerated niobium titanium oxide was confirmed in a coin-shaped cell prepared in the same manner as above, it was found to be 266 mAh/g, confirming that the capacity of the niobium titanium oxide had been recovered.

Table 1 shows the temperature and time of the second heat treatment and the first heat treatment, the capacity after the second heat treatment, and the capacity after the first heat treatment in Examples 1-4.

According to the recycling system of at least one of these embodiments or examples, there is provided a water dispersion device for dispersing electrodes containing niobium titanium oxide in water, and a solid-liquid separation device for separating niobium titanium oxide from the electrodes dispersed in water. and a first heat treatment device that heat-treats the separated niobium titanium oxide, so that reusable niobium titanium oxide can be recovered from the electrode or the battery.
(Example 5)
Recycling of niobium titanium oxide was carried out for a battery (hereinafter referred to as a treated battery) equipped with a TNO electrode as a negative electrode and using a metal can as an exterior member.

The batteries to be treated that were incorporated in the waste module were separated and only the batteries to be treated were taken out. This removed battery was set in a charging/discharging device, and discharge treatment was performed at a current value of 1C. At this time, after reaching the discharge reference voltage of this battery of 1.5 V, additional discharge was performed for an additional 5 minutes. The battery subjected to this discharge treatment was placed in a third heat treatment device maintained at 600°C. The heat treatment time was 60 minutes (1 hour). After the powder containing niobium titanium oxide obtained here was cooled to 25° C. or lower, it was immersed in an acid aqueous solution for 1 hour. The acid aqueous solution was a nitric acid aqueous solution with a pH of 1, and was maintained at 40°C. Thereafter, the niobium titanium oxide was separated using a cyclone. Thereafter, ions remaining in the niobium titanium oxide were removed by washing with water. The niobium titanium oxide was represented by Nb ₂ TiO ₇ .

A portion of the niobium titanium oxide obtained here was taken, and 80% by mass of niobium titanium oxide was mixed with 10% by mass of acetylene black as a conductive agent and 10% by mass of CMC as a binder, and these were kneaded with a water solvent to prepare a slurry. The slurry was applied to an aluminum foil, and then dried and pressed to prepare an electrode. A coin-shaped cell was made using the obtained electrode, and the capacity of the niobium titanium oxide was confirmed to be 231 mAh/g.

The remaining niobium titanium oxide, a portion of which was taken out as described above, was put into a first heat treatment apparatus, and a first heat treatment was performed at 900° C. for 60 minutes in the atmosphere to obtain a regenerated niobium titanium oxide. A coin-shaped cell was produced using this regenerated niobium titanium oxide in the same manner as described above, and the capacity was confirmed to be 255 mAh/g, confirming that the capacity of the niobium titanium oxide had been recovered.
(Example 6)
Recycling of niobium titanium oxide was carried out for a battery (hereinafter referred to as a treated battery) equipped with a TNO electrode as a negative electrode and using a metal can as an exterior member.

After performing discharge treatment, third heat treatment, acid treatment, and solid-liquid separation in the same manner as in Example 5, except that a sulfuric acid aqueous solution with a pH of 1 was used as the acid aqueous solution while being maintained at 40°C, niobium titanium oxide was prepared. When the capacity was confirmed in the same manner as in Example 5, it was 235 mAh/g.

The remaining niobium titanium oxide, which had been removed as described above, was subjected to the first heat treatment in the same manner as in Example 5 to obtain regenerated niobium titanium oxide. A coin-type cell was produced using this regenerated niobium titanium oxide in the same manner as described above, and the capacity was confirmed to be 253 mAh/g, confirming that the capacity of the niobium titanium oxide had been restored.

Table 2 shows the temperature and time of the third heat treatment and the first heat treatment, the capacity after the third heat treatment, and the capacity after the first heat treatment in Examples 5 and 6.

As shown in Table 2, according to the recycling method of the embodiment, the battery to be treated that includes a positive electrode and a negative electrode containing niobium titanium oxide is subjected to a third heat treatment, the battery to be treated is subjected to an acid treatment, and the battery to be treated is subjected to an acid treatment. This process involves separating niobium titanium oxide from the treated battery and subjecting the separated niobium titanium oxide to a first heat treatment. It is possible to safely and easily recover and regenerate materials from the battery to be treated.

Inventions related to embodiments will be additionally described below.

(1) A water dispersion device that disperses an electrode containing niobium titanium oxide in water;
A recycling system comprising: a solid-liquid separation device that separates the niobium titanium oxide from the electrode dispersed in the water; and a first heat treatment device that heat-treats the separated niobium titanium oxide.

(2) The recycling system according to (1), further including a second heat treatment device that heat-treats the electrode before water dispersion.

(3) The recycling system according to (2), further including a separation device that separates the electrode from a battery containing the electrode as a positive electrode and a negative electrode.

(4) The recycling system according to (1), further comprising a separation device that separates the electrode from a battery containing the electrode as a positive electrode and a negative electrode.

(5) dispersing an electrode comprising niobium titanium oxide in water;
separating the niobium titanium oxide from the electrode dispersed in water;
and subjecting the separated niobium titanium oxide to a first heat treatment.

(6) The recycling method according to (5), further comprising a step of subjecting the electrodes to a second heat treatment prior to the aqueous dispersion step.

(7) The recycling method according to (6), which includes a step of separating the electrode from a battery containing the electrode as a positive electrode and a negative electrode, before the second heat treatment step.

(8) The recycling method according to (5), further comprising a step of separating the electrode from a battery containing the electrode as a positive electrode and a negative electrode, prior to the aqueous dispersion step.

(9) A method for manufacturing an electrode, comprising manufacturing an electrode using niobium titanium oxide recovered by the recycling system or recycling method according to any one of (1) to (8).

(10) manufacturing an electrode using the niobium titanium oxide recovered by the recycling system or recycling method according to any one of (1) to (8);
A method for manufacturing a battery, comprising the step of manufacturing a battery including the electrode.

(11) The niobium titanium oxide is a niobium titanium oxide represented by the general formula Li _x Ti _1-y M1 _y Nb _2-z M2 _z O _7+δ , and a niobium titanium oxide represented by the general formula Li _x Ti _1-y M3 _y+ Contains at least one selected from the group consisting of niobium titanium oxides represented by _z Nb _2-z O _7-δ ,
The M1 is at least one selected from the group consisting of Zr, Si, and Sn, the M2 is at least one selected from the group consisting of V, Ta, and Bi, and the M3 is: at least one selected from the group consisting of Mg, Fe, Ni, Co, W, Ta, and Mo; the x satisfies 0≦x≦5; the y satisfies 0≦y<1; The recycling system or recycling method according to any one of (1) to (10), wherein z satisfies 0≦z<2, and the δ satisfies -0.3≦δ≦0.3.
(12)
a step of subjecting a battery including a positive electrode and a negative electrode containing niobium titanium oxide to a third heat treatment;
treating the battery with an acidic solvent;
separating the niobium titanium oxide from the battery treated with the acidic solvent;
A recycling method comprising the step of subjecting the separated niobium titanium oxide to a first heat treatment.
(13)
The recycling method according to (12), wherein the battery further includes an exterior member.
(14)
The recycling method according to (12) or (13), further comprising, before the step of treating the battery with an acidic solvent, pulverizing the battery that has been subjected to the third heat treatment.
(15)
The recycling method according to any one of (12) to (14), wherein the acidic solvent contains at least one of nitric acid and sulfuric acid.
(16)
A method for manufacturing an electrode, comprising manufacturing an electrode using niobium titanium oxide recovered by the recycling method according to any one of (12) to (15).
(17)
A step of manufacturing an electrode using the niobium titanium oxide recovered by the recycling method according to any one of (12) to (15);
A method for manufacturing a battery, comprising the step of manufacturing a battery including the electrode.
(18)
a third heat treatment device that performs a third heat treatment on a battery including a positive electrode and a negative electrode containing niobium titanium oxide;
an acid treatment device for treating the battery subjected to the third heat treatment with an acidic solvent;
a solid-liquid separator that separates the niobium titanium oxide from the battery treated with the acidic solvent;
a first heat treatment device that performs a first heat treatment on the separated niobium titanium oxide.
(19) The niobium titanium oxide has the general formula Li _x Ti _1-y M1 _y Nb _2-z M2 _z O _7+δ , and the general formula Li _x Ti _1-y M3 _y+ Contains at least one selected from the group consisting of niobium titanium oxides represented by _z Nb _2-z O _7-δ ,
The M1 is at least one selected from the group consisting of Zr, Si, and Sn, the M2 is at least one selected from the group consisting of V, Ta, and Bi, and the M3 is: at least one selected from the group consisting of Mg, Fe, Ni, Co, W, Ta, and Mo; the x satisfies 0≦x≦5; the y satisfies 0≦y<1; The recycling system or recycling method according to any one of (12) to (18), wherein z satisfies 0≦z<2, and the δ satisfies -0.3≦δ≦0.3.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

DESCRIPTION OF SYMBOLS 1... Water dispersion device, 2... Solid-liquid separation device, 3... First heat treatment device, 4... Second heat treatment device, 5... Discharge treatment device, 6... Exterior separation device, 7... Positive and negative electrode separation device, 8... Chamber, DESCRIPTION OF SYMBOLS 10...Third heat treatment device, 11...Crushing device, 12...Acid treatment device, 20...Nonaqueous electrolyte battery, 21...Metal container, 22...Electrode group, 23...Metal sealing plate, 24...Negative electrode terminal, 25... Positive electrode terminal, 26... negative electrode, 26a... negative electrode current collector, 26b... negative electrode active material containing layer, 27... positive electrode, 27a... positive electrode current collector, 27b... positive electrode active material containing layer, 28... separator, 29... negative electrode current collector Tab, 30... Insulating member, 31... Positive electrode current collecting tab, 100, 101, 102, 103... Recycling system, S1... Water dispersion, S2... Solid-liquid separation, S3... First heat treatment, S4... Second heat treatment, S5... Discharge treatment, S6...Exterior separation, S7...Positive and negative electrode separation, S10...Discharge treatment, S11...Third heat treatment, S12...Crushing, S13...Acid treatment, S14...Solid-liquid separation, S15...First heat treatment.

Claims (18)

a water dispersion device for dispersing an electrode containing niobium titanium oxide in water;
A recycling system comprising: a solid-liquid separation device that separates the niobium titanium oxide from the electrode dispersed in the water; and a first heat treatment device that heat-treats the separated niobium titanium oxide. The recycling system according to claim 1, further comprising a second heat treatment device for heat treating the electrode before water dispersion. 3. The recycling system according to claim 2, further comprising a separation device for separating the electrode from a battery including a positive electrode and the electrode as a negative electrode. The recycling system according to claim 1, further comprising a positive electrode and a separation device for separating the electrode from a battery including the electrode as a negative electrode. dispersing an electrode containing niobium titanium oxide in water;
separating the niobium titanium oxide from the electrode dispersed in the water;
A recycling method comprising the step of subjecting the separated niobium titanium oxide to a first heat treatment. The recycling method according to claim 5, further comprising a step of subjecting the electrode to a second heat treatment before the water dispersion step. 7. The recycling method according to claim 6, further comprising a step of separating the electrode from a battery including the electrode as a positive electrode and a negative electrode, before the second heat treatment step. 6. The recycling method according to claim 5, further comprising a step of separating the electrode from a battery including the electrode as a positive electrode and a negative electrode, before the water dispersion step. A method for manufacturing an electrode, comprising manufacturing an electrode using niobium titanium oxide recovered by the recycling method according to any one of claims 5 to 8. A step of manufacturing an electrode using the niobium titanium oxide recovered by the recycling method according to any one of claims 5 to 8;
A method for manufacturing a battery, comprising the step of manufacturing a battery including the electrode. The niobium titanium oxide has the general formula Li _x Ti _1-y M1 _y Nb _2-z M2 _z O _7+δ , and the general formula Li _x Ti _1-y M3 _y+z Nb _{2 -z} O _7-δ Containing at least one selected from the group consisting of niobium titanium oxides,
The M1 is at least one selected from the group consisting of Zr, Si, and Sn, the M2 is at least one selected from the group consisting of V, Ta, and Bi, and the M3 is: at least one selected from the group consisting of Mg, Fe, Ni, Co, W, Ta, and Mo; the x satisfies 0≦x≦5; the y satisfies 0≦y<1; The recycling system according to any one of claims 1 to 4, wherein z satisfies 0≦z<2, and the δ satisfies -0.3≦δ≦0.3. a step of subjecting a battery including a positive electrode and a negative electrode containing niobium titanium oxide to a third heat treatment;
treating the battery with an acidic solvent;
separating the niobium titanium oxide from the battery treated with the acidic solvent;
A recycling method comprising the step of subjecting the separated niobium titanium oxide to a first heat treatment. The recycling method according to claim 12, wherein the battery further includes an exterior member. 13. The recycling method according to claim 12, further comprising the step of pulverizing the battery subjected to the third heat treatment before the step of treating the battery with an acidic solvent. The recycling method according to claim 12, wherein the acidic solvent contains at least one of nitric acid and sulfuric acid. A method for manufacturing an electrode, comprising manufacturing an electrode using niobium titanium oxide recovered by the recycling method according to any one of claims 12 to 15. A step of manufacturing an electrode using the niobium titanium oxide recovered by the recycling method according to any one of claims 12 to 15;
A method for manufacturing a battery, comprising the step of manufacturing a battery including the electrode. a third heat treatment device that performs a third heat treatment on a battery including a positive electrode and a negative electrode containing niobium titanium oxide;
an acid treatment device for treating the battery subjected to the third heat treatment with an acidic solvent;
a solid-liquid separator that separates the niobium titanium oxide from the battery treated with the acidic solvent;
a first heat treatment device that performs a first heat treatment on the separated niobium titanium oxide.