Treatment vessel of lithium ion secondary battery

Abstract

To stably separate molten metal such as aluminum and a non-molten material from a lithium ion secondary battery.SOLUTION: A treatment vessel of a lithium ion secondary battery is used when housing a lithium ion secondary battery and performing heating treatment at a temperature higher than the fusion point of aluminum, and has a body part housing a lithium ion secondary battery, and an openable / closable lid part, where the body part has a first opening for separating molten aluminum to the outside of the vessel on a bottom thereof, the lid part has one or a plurality of second openings on a top face, and a plurality of cylindrical support parts are provided outside the bottom face of the body part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a treatment container for a lithium ion secondary battery. [Background technology]

[0002] Methods for incinerating used lithium-ion secondary batteries and separating and recovering valuable materials are known. For example, Patent Document 1 discloses a molten metal collection container used in an incinerator that incinerates lithium-ion secondary batteries containing a metal that melts at 700°C to 1000°C at a temperature higher than the melting point of the metal, the container having a shape that receives the lithium-ion secondary batteries and that receives the molten metal that flows out from the lithium-ion secondary batteries, the inner surface of the container having a sticking-inhibiting surface that inhibits the molten metal from sticking, and a support member for the lithium-ion secondary batteries that protrudes upward from the inner bottom surface of the container so as to form a support portion that supports the lithium-ion secondary batteries at a position higher than the inner bottom surface of the container and a storage portion that stores the molten metal.

[0003] Furthermore, for example, Patent Document 2 discloses a method for recovering valuables from lithium ion batteries, which includes a melting and separation step in which used lithium ion batteries, which use at least aluminum as a constituent material of the battery case, are heated at a temperature of 660°C or higher to melt the aluminum material, thereby separating the molten aluminum material from the non-molten material that constitutes the battery main body, and a crushing step in which the non-molten material obtained in the melting and separation step is crushed to obtain a crushed product, wherein in the melting and separation step, the used lithium ion batteries placed on a mesh body are heated at a temperature of 660°C or higher, thereby melting the aluminum material and causing it to drop through the mesh of the mesh body, and leaving the non-molten material that constitutes the battery main body on the mesh body, thereby separating the molten aluminum material from the non-molten material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-138996 [Patent Document 2] Patent No. 6268130 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of one embodiment of the present invention is to stably and efficiently separate molten metal such as aluminum from non-molten material from a lithium-ion secondary battery. In particular, the present invention provides a technology that enables stable heat treatment even in the state of a module (or pack) that is an assembly of multiple lithium-ion secondary battery cells. [Means for solving the problem]

[0006] A first aspect of the present invention is A treatment container for lithium ion secondary batteries that contains lithium ion secondary batteries and is used when performing heat treatment at a temperature higher than the melting point of aluminum, The battery pack has a main body that houses a lithium-ion secondary battery and an openable and closable lid. the main body has a first opening at its bottom for separating molten aluminum out of the container; the lid portion has one or more second openings on its top surface; The treatment container for lithium ion secondary batteries has a plurality of cylindrical support parts provided on the outside of the bottom surface of the main body.

[0007] A second aspect of the present invention is In the treatment container for lithium ion secondary batteries according to the first aspect, the lid portion is also provided with a plurality of the support portions.

[0008] A third aspect of the present invention is In the treatment container for lithium ion secondary batteries according to the first aspect, the lid is configured to cover at least a part of a side surface of the main body.

[0009] A fourth aspect of the present invention is In the treatment container for a lithium ion secondary battery according to the first aspect, the first opening has a slit shape.

[0010] A fifth aspect of the present invention is In the treatment container for lithium ion secondary batteries according to the fourth aspect, the intersection of the longitudinal direction of the first opening and the longitudinal direction of the support part of the main body part is located on the bottom surface of the main body part.

[0011] A sixth aspect of the present invention is a method for manufacturing a semiconductor device comprising: In the treatment container for a lithium ion secondary battery according to the first aspect, the second opening has a circular or elliptical shape.

[0012] A seventh aspect of the present invention is In the treatment container for lithium ion secondary batteries according to the first aspect, the second opening has an opening ratio of 2% to 20% of the area of ​​the entire upper surface of the lid.

[0013] An eighth aspect of the present invention is The treatment container for lithium ion secondary batteries according to the first aspect, wherein the inner wall of the main body is coated with alumina. [Effects of the Invention]

[0014] According to one embodiment of the present invention, it is possible to stably and efficiently separate molten metal such as aluminum from non-molten material from a lithium ion secondary battery. In particular, the lithium ion secondary battery can be stably heat-treated even when the battery is in the form of a module which is an assembly of multiple cells or a pack having multiple modules. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1(a) is a schematic diagram (plan view) showing an example of a processing container 10 for a lithium ion secondary battery according to the first embodiment of the present invention, and FIG. 1(b) is a side view of FIG. 1(a). [Figure 2]FIG. 2 is a flowchart showing an example of a method for treating a lithium ion secondary battery according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a schematic diagram showing an example of a case in which a lithium ion secondary battery 20 is arranged in a container 10 according to the first embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] <Insights gained by the inventor> First, the findings of the inventors will be explained.

[0017] For example, when lithium-ion secondary batteries are placed in a container such as that described in Patent Document 1 and incinerated, it has been found that a large amount of other battery materials are mixed into the molten metal such as aluminum, making it difficult to separate them.

[0018] Furthermore, for example, when a certain amount or more of lithium ion secondary batteries are placed on a mesh as described in Patent Document 2 and then transported or handled, it has been found that the use of the mesh makes it easy for the lithium ion secondary batteries to become unstable during handling such as transportation, and the terminals may come into contact with a conductive object (such as a container), causing a short circuit and resulting in sudden heat generation or fire. Furthermore, no consideration is given to the efficiency of recovering the unmelted material remaining on the mesh.

[0019] The inventors conducted extensive research into the above-mentioned problems. As a result, they discovered a processing container having a main body for housing a lithium-ion secondary battery and an openable lid. The main body has a first opening at the bottom for separating molten aluminum outside the container, the lid has one or more second openings on the top surface, and multiple cylindrical supports on the outside bottom surface of the main body. This facilitates the flow of molten metal, such as aluminum, out of the container, while other battery materials (especially black mass) remain inside the container. In other words, the container has holes in the bottom, allowing materials that would pass through a mesh to remain inside the container. Furthermore, this prevents sudden heat generation and fire due to terminal contact during storage and transportation before heating and when placed in a heating furnace. Furthermore, it also enables the efficient recovery of unmelted battery materials remaining on the bottom.

[0020] Furthermore, if a lithium-ion secondary battery is subjected to a heat treatment while it is in the form of a module, which is an assembly of multiple cells, or a pack containing multiple modules, the internal pressure inside the treatment container may increase, potentially causing the lid to blow off. By using the treatment container described above, the atmosphere and internal pressure inside the container can be appropriately controlled, even when the lithium-ion secondary battery is housed in the treatment container in the form of a module or pack and subjected to a heat treatment, enabling a stable heat treatment. Here, the term "lithium-ion secondary battery" as used herein includes three units: a cell, a module, and a pack. A cell is the smallest unit that functions as a battery by itself. In contrast, a module is a case in which multiple cells are connected together, and a pack is a case in which multiple modules are connected together.

[0021] [Details of the embodiment of the present invention] Next, an embodiment of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0022] In this specification, "A to B" means a numerical range of "A or more and B or less."

[0023] <First embodiment of the present invention> (1) Lithium-ion secondary battery treatment container First, a lithium-ion secondary battery treatment container 10 (hereinafter simply referred to as container 10) used in this embodiment will be described. The container 10 is used to store lithium-ion secondary batteries 20 containing aluminum and to perform heat treatment at a temperature higher than the melting point of aluminum (for example, 660°C or higher and 1000°C or lower). Considering the heating temperature of the heat treatment, the container 10 is preferably made of, for example, SUS304.

[0024] 1(a) and 1(b) are schematic diagrams showing an example of a container 10 used in this embodiment, with FIG. 1(a) being a plan view seen from above and FIG. 1(b) being a side view. As shown in FIGS. 1(a) and 1(b), the container 10 has a main body 11 that houses a lithium-ion secondary battery 20 and a lid 12 that can be opened and closed by being attached to and detached from the main body 11. Note that FIG. 1(a) shows a state in which the lid 12 is detached from the main body 11 (open state), and FIG. 1(b) shows a state in which the lid 12 is attached to the main body 11 (closed state).

[0025] 1(a), the main body 11 has a first opening 13 at the bottom. The first opening 13 is a hole for separating molten aluminum that flows out of the lithium-ion secondary battery 20 during the heat treatment to the outside of the container 10. This allows stable separation of the aluminum from other battery materials.

[0026] The shape and number of the first openings 13 are not critical as long as they can adequately recover the molten aluminum and maintain the necessary bottom strength. However, a hole size large enough to allow a 10 mm diameter sphere to pass through is preferred. The first openings 13 can be formed in easily processable shapes such as circles, ellipses, and polygons. For example, they can be slit-shaped as shown in FIG. 1(a). In this case, the width is preferably 10 mm to 50 mm. As shown in FIG. 1(a), the first openings 13 are preferably slits extending along the long side of the main body 11 and arranged at a predetermined interval. By providing such first openings 13 at the bottom, the strength of the container 10 can be maintained while enabling the separation of the molten aluminum and the battery materials. The bottom of the main body 11 is not particularly limited as long as the molten aluminum flows out of it. It may be a flat surface parallel to the floor or may be inclined toward the first openings 13. From the perspective of efficiently separating the molten aluminum, it is preferred that the first openings 13 be formed at the lowest position of the bottom.

[0027] The area of ​​the first openings 13 (or the total area of ​​the first openings 13 if there are multiple first openings 13) is preferably 1% or more and 10% or less of the bottom area of ​​the main body 11. If the total area of ​​the first openings 13 is less than 1% of the bottom area, it may be difficult to separate the molten aluminum outside the container 10. In contrast, by making the total area of ​​the first openings 13 1% or more of the bottom area, it becomes easier to separate the molten aluminum outside the container 10. On the other hand, if the total area of ​​the first openings 13 exceeds 10% of the bottom area, the strength of the container 10 may decrease. In contrast, by making the total area of ​​the first openings 13 10% or less of the bottom area, the strength of the container 10 can be maintained.

[0028] The long side a of the main body 11 is preferably, for example, 1500 mm or more and 3000 mm or less, the short side b is preferably, for example, 1000 mm or more and 2000 mm or less, and the depth d is preferably, for example, 300 mm or more and 500 mm or less. The above numerical ranges are sizes that allow the lithium ion secondary batteries 20 to be treated to be heat-treated even when they are in the form of a module or a pack. In addition, the thickness of the bottom and sides of the main body 11 is preferably a thickness that allows the strength of the container 10 to be maintained during the heat treatment.

[0029] As shown in FIG. 1(b), a plurality of cylindrical support portions 15 (two in this embodiment) are provided on the outer bottom surface of the main body portion 11. The support portions 15 serve as fork pockets when transporting the container 10 using a forklift or the like, for example. This allows the container 10 to be easily transported. Furthermore, as shown in FIG. 1(a), it is preferable that the first openings 13 are arranged so as to avoid the areas where the support portions 15 are provided.

[0030] As shown in FIG. 1(a), when first opening 13 has a slit shape in a plan view seen from above, it is preferable that its longitudinal direction intersect (or be perpendicular to) the longitudinal direction of support portion 15. In other words, it is preferable that the intersection of the longitudinal direction of first opening 13 and the longitudinal direction of support portion 15 is located on the bottom surface. This makes it easier to maintain the strength of container 10. Furthermore, deformation of container 10 during heat treatment is suppressed, making it easier to reuse container 10. Note that support portion 15 may be provided parallel to the longitudinal direction of first opening 13, or may be provided in multiple directions (for example, in the long side direction and short side direction of main body portion 11).

[0031] 1(a), one or more (five in this embodiment) second openings 14 for controlling the atmosphere and internal pressure inside the container during heat treatment are provided on the top surface of the lid 12. This allows the atmosphere and internal pressure inside the container 10 to be appropriately controlled even when lithium ion secondary batteries 20 are stored in the container 10 in a module (or pack) state and subjected to heat treatment, thereby enabling stable heat treatment.

[0032] As shown in FIG. 1(b), it is preferable that the lid portion 12 also has a plurality of support portions 15 (two in this embodiment). This allows the lid portion 12 to be easily transported. Furthermore, as shown in FIG. 1(a), it is preferable that the second openings 14 are arranged so as to avoid the areas where the support portions 15 are provided. Note that the position, direction, and number of the support portions 15 provided on the lid portion 12 are not particularly limited, but it is preferable that they are provided at positions corresponding to the support portions 15 provided on the main body portion 11, as shown in FIG. 1(b).

[0033] As shown in FIG. 1(b), the lid 12 is preferably configured to cover at least a portion of the side surface of the main body 11. As a result, even if a heat treatment is performed using a burner from the side of the container 10, direct flame is unlikely to reach the lithium-ion secondary battery 20, and oxidation (embrittlement) of the negative electrode current collector of the lithium-ion secondary battery 20 can be suppressed. If oxidation (embrittlement) of the negative electrode current collector occurs, there is a risk that the recovery rate of valuable materials (e.g., copper) will decrease in a subsequent process. In contrast, by suppressing oxidation (embrittlement) of the negative electrode current collector, the recovery rate of valuable materials in a subsequent process can be improved.

[0034] The shape of the second openings 14 is preferably, for example, circular or elliptical. This allows gas generated during the heat treatment to be easily released to the outside of the main body 11, making it easier to suppress the occurrence of a deflagration state. For the same reason, it is preferable to provide three or more second openings 14, and more preferably five or more second openings 14. This makes it easier to appropriately control the atmosphere and internal pressure within the container 10.

[0035] The second opening 14 preferably has an opening ratio of 2% to 20% of the total area of ​​the top surface of the lid 12. If the opening ratio is less than 2%, the internal pressure of the container 10 may increase during the heat treatment. In contrast, by setting the opening ratio to 2% or more, it is possible to prevent the internal pressure of the container 10 from increasing during the heat treatment. On the other hand, if the opening ratio exceeds 20%, the oxygen concentration in the container 10 may increase during the heat treatment, which may cause the negative electrode current collector to oxidize (become embrittled). In contrast, by setting the opening ratio to 20% or less, it is possible to appropriately control the oxygen concentration in the container 10 during the heat treatment and prevent the negative electrode current collector from being oxidized (become embrittled). More preferably, the opening ratio is 4% to 15% of the total area of ​​the top surface, and even more preferably 4% to 8%.

[0036] The inner walls (inner sides and inner bottom) of the main body 11 are preferably coated with, for example, alumina, which prevents the molten aluminum from remaining in the container 10 for a long period of time, thereby preventing deterioration and deformation of the container 10.

[0037] (2) Disposal method for lithium-ion secondary batteries Next, a method for treating a lithium ion secondary battery according to this embodiment will be described. The method for treating a lithium ion secondary battery according to this embodiment is a method for heat treating a lithium ion secondary battery 20 containing aluminum at a temperature higher than the melting point of aluminum (for example, 660°C or higher and 1000°C or lower). Fig. 2 is a flowchart showing an example of the method for treating a lithium ion secondary battery according to this embodiment. As shown in Fig. 2, the method for treating a lithium ion secondary battery according to this embodiment includes, for example, an arrangement step S101, a heating step S102, and a recovery step S103.

[0038] (Placement process S101) The arrangement step S101 is, for example, a step of arranging lithium ion secondary batteries 20 in a container 10. Fig. 3 is a schematic diagram showing an example of a case where a module or pack of lithium ion secondary batteries 20 is arranged in the container 10. The method for treating lithium ion secondary batteries of this embodiment uses the above-mentioned container 10, and therefore, stable heat treatment is possible even when the lithium ion secondary batteries 20 are in the form of a module or pack.

[0039] 3, in the placement step S101, the lithium ion secondary battery 20 is placed in the container 10 (inside the main body 11), and then the lid 12 having the second opening 14 is attached. This makes it possible to appropriately suppress oxidation of the lithium ion secondary battery 20 during the heat treatment.

[0040] (Heating process S102) The heating step S102 is, for example, a step of heating the lithium ion secondary battery 20 and separating molten aluminum flowing out of the lithium ion secondary battery 20 from the container 10 through the first opening 13. A known heating furnace or the like can be used for the heating treatment. The separated aluminum may be collected after the heating treatment in a separate collection container disposed below the container 10, for example.

[0041] In the heating step S102, it is preferable to heat the lithium ion secondary battery 20 in a reducing atmosphere, for example, so that oxidation of various metals contained in the lithium ion secondary battery 20 can be suppressed.

[0042] (Recovery step S103) The recovery step S103 is a step in which, for example, after the heating treatment, the container 10 is removed from the heating furnace, and the battery material from which the aluminum has been separated (metal materials other than aluminum contained in the lithium ion secondary battery 20, etc.) is recovered from inside the container 10.

[0043] The above steps enable stable heat treatment of the lithium ion secondary battery 20. Specifically, the lithium ion secondary battery 20 is heat treated, and the molten aluminum and other battery materials can be stably separated. Note that valuables may be recovered from the battery materials from which the aluminum has been separated by known means such as crushing and separation.

[0044] <Other Embodiments of the Present Invention> Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit of the present invention.

[0045] For example, in the above embodiment, the lid portion 12 is made up of a single member, but the lid portion 12 may be made up of multiple members.

[0046] For example, in the above embodiment, the case where support portion 15 is provided on the upper surface of lid portion 12 has been described, but support portion 15 may be provided on the lower surface of lid portion 12. In this case, it is preferable to provide a recess on the upper edge of the side surface of main body portion 11 so that support portion 15 of lid portion 12 fits into it. [Explanation of symbols]

[0047] 10 Container (processing container) 11 Main body 12 Lid 13 First Opening 14 Second opening 15 Support part 20 Lithium-ion secondary battery S101 Placement process S102 Heating process S103 Recovery process

Claims

1. A treatment container for lithium ion secondary batteries that contains lithium ion secondary batteries and is used when performing heat treatment at a temperature higher than the melting point of aluminum, The battery pack has a main body that houses a lithium-ion secondary battery and an openable and closable lid. the main body has a first opening at its bottom for separating molten aluminum out of the container; the lid portion has one or more second openings on an upper surface; A treatment container for lithium ion secondary batteries, wherein a plurality of cylindrical support portions are provided on the outside of the bottom surface of the main body portion.

2. The treatment container for lithium ion secondary batteries according to claim 1 , wherein the lid portion is also provided with a plurality of the support portions.

3. The treatment container for lithium ion secondary batteries according to claim 1 , wherein the lid portion is configured to cover at least a part of a side surface of the main body portion.

4. The treatment container for lithium ion secondary batteries according to claim 1 , wherein the first opening has a slit shape.

5. The treatment container for lithium ion secondary batteries according to claim 4 , wherein an intersection of a longitudinal direction of the first opening and a longitudinal direction of the support portion of the main body portion exists on a bottom surface of the main body portion.

6. The treatment container for lithium ion secondary batteries according to claim 1 , wherein the second opening has a circular or elliptical shape.

7. The treatment container for lithium ion secondary batteries according to claim 1 , wherein the second opening has an opening ratio of 2% to 20% of the total area of ​​the upper surface of the lid.

8. The treatment container for lithium ion secondary batteries according to claim 1 , wherein the inner wall of the main body is coated with alumina.

Images