Electrolytic solution recovery method for power storage device

Abstract

To more reliably recover an electrolyte in recycling of a power storage device.SOLUTION: The method of collecting electrolytic solution 15 of rechargeable lithium ion battery 10 includes an installation step S2 and a hole forming step S3. In the installation step S2, the rechargeable lithium ion battery 10 is installed inside the chamber 110 so that the projecting pin 161 is positioned directly below the 42a of the hole opening portion of the case 41. In the hole forming step S3, the table 140 is lowered and inserted into the 42a of the hole forming portion.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for recovering an electrolyte from an electricity storage device. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2013-4299 discloses a recycling method for separating lithium-ion secondary batteries in order to recover valuable metals. Recycling lithium-ion secondary batteries requires the removal of the electrolyte solution injected inside the lithium-ion secondary battery. The method disclosed in this publication involves opening a through-hole in a sealing plate that seals the lithium-ion secondary battery container, then placing the lithium-ion secondary battery in a vacuum dryer to evaporate the electrolyte solution. This is said to remove the electrolyte solution from inside the lithium-ion secondary battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-4299 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, the inventors of the present application wish to recover the electrolyte more efficiently when recycling electricity storage devices. [Means for solving the problem]

[0005] The method for recovering electrolyte from an electricity storage device disclosed herein includes the steps of preparing an electricity storage device in which an electrode body and an electrolyte are housed inside a case, an installation step of installing the electricity storage device inside a sealed chamber, and a step of reducing the pressure inside the chamber and, in the reduced pressure atmosphere, drilling a hole in the bottom of the case installed inside the chamber in the installation step.

[0006] According to this method for recovering an electrolyte solution, the electrolyte solution can be recovered more efficiently when recycling an electricity storage device. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of a lithium ion secondary battery 10. As shown in FIG. [Figure 2] FIG. 2 is a schematic vertical cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a schematic diagram of the electrode body 20. As shown in FIG. [Figure 4] FIG. 4 is a vertical cross-sectional view of the lithium ion secondary battery 10. As shown in FIG. [Figure 5] FIG. 5 is a schematic diagram showing an electrolyte recovery device 100 according to the first embodiment. [Figure 6] FIG. 6 is a flowchart showing the procedure for recovering the electrolyte solution 15. [Figure 7] FIG. 7 is an enlarged view of the vicinity of the protruding pin 161 when the protruding pin 161 penetrates the hole portion 42a. [Figure 8] FIG. 8 is a diagram showing an electrolyte recovery device 100B according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] The disclosure herein is explained below. Unless otherwise specified, the disclosure herein is not intended to limit the invention described in the claims of this application. Each drawing is a schematic representation and does not necessarily reflect the actual product. Furthermore, components and parts that perform the same function are appropriately designated by the same reference numerals, and redundant explanations will be omitted.

[0009] Disclosed herein is a method for recovering an electrolyte from an electricity storage device. In the disclosed method for recovering an electrolyte from an electricity storage device, for example, a lithium ion secondary battery is used as the electricity storage device. The electrode body of the lithium ion secondary battery has, for example, a positive electrode current collector made of aluminum or an aluminum alloy and a negative electrode current collector made of copper or a copper alloy.

[0010] First Embodiment <Lithium-ion secondary battery 10> FIG. 1 is a perspective view of a lithium-ion secondary battery 10. FIG. 2 is a schematic longitudinal sectional view taken along line II-II in FIG. 1. FIG. 3 is a schematic view of an electrode assembly 20. FIG. 2 illustrates a state in which the interior of the lithium-ion secondary battery 10 is exposed along one wide surface of a substantially rectangular parallelepiped case 41. FIG. 2 also illustrates a partially cutaway partial sectional view of the electrode assembly 20. The lithium-ion secondary battery 10 illustrated in FIG. 2 is a so-called sealed battery in which the case 41 housing the electrode assembly 20 is sealed. In this embodiment, the case 41 is a metal case having a substantially rectangular parallelepiped shape. In the drawings, the symbol X indicates the long side direction of the case 41. The symbol Y (see FIG. 1) indicates the short side direction perpendicular to the long side direction. The symbol Z indicates the height direction perpendicular to the short side direction and the long side direction. The structure of the case 41 is not limited to this form. For example, the case 41 may be a so-called bag-shaped laminate case that covers the electrode assembly 20.

[0011] As shown in FIG. 2, the lithium-ion secondary battery 10 includes an electrode assembly 20 and a case 41. The case 41 includes a case body 41a having an opening 41a1, a sealing plate 41b that closes the opening 41a1 of the case body 41a, a positive electrode terminal 50, and a negative electrode terminal 60. The sealing plate 41b is an example of a lid according to the present invention. The case body 41a houses the electrode assembly 20. Internal terminals 55, 65 and external terminals 51, 61 are attached to the sealing plate 41b via a gasket 70 and an insulator 80. In this embodiment, the internal terminal 55 is connected to the positive electrode current collector 21a of the electrode assembly 20. The external terminal 51 is connected to the internal terminal 55 and constitutes the positive electrode terminal 50 on the outside of the case 41. The internal terminal 65 is connected to the negative electrode current collector 22a of the electrode assembly 20 (see FIG. 3). The external terminal 61 is connected to the internal terminal 65 and forms a negative terminal 60 outside the case 41 .

[0012] <Electrode body 20> As shown in FIG. 3 , in the electrode assembly 20, a positive electrode element 21 and a negative electrode element 22 face each other with a separator interposed therebetween. The positive electrode element 21 includes a positive electrode current collector 21a and a positive electrode active material layer 21b formed on the positive electrode current collector 21a and containing a positive electrode active material. The negative electrode element 22 includes a negative electrode current collector 22a and a negative electrode active material layer 22b formed on the negative electrode current collector 22a and containing a negative electrode active material. The positive electrode element 21 and the negative electrode element 22 may each be sheet-shaped. In this case, the positive electrode element may be, for example, a sheet-shaped member in which the positive electrode active material layers 21b are formed on both sides of the positive electrode current collector 21a made of metal foil with a predetermined width and thickness. The negative electrode element may be a sheet-shaped member in which the negative electrode active material layers 22b are formed on both sides of the negative electrode current collector 22a made of metal foil with a predetermined width and thickness. The sheet-like positive electrode element 21 is called a positive electrode sheet, and the sheet-like negative electrode sheet is called a negative electrode sheet.

[0013] For example, the electrode assembly 20 may be a so-called wound electrode assembly. The electrode assembly 20 is composed of a positive electrode sheet 21 as a positive electrode element, a negative electrode sheet 22 as a negative electrode element, and separator sheets 31 and 32 as separators. The positive electrode sheet 21, the first separator sheet 31, the negative electrode sheet 22, and the second separator sheet 32 ​​are each long strip-shaped members that are stacked and wound with their length and width directions aligned. The electrode assembly 20 is housed in a case 41 while covered with an insulating film (not shown) or the like.

[0014] <Positive electrode sheet 21> The positive electrode sheet 21 has a positive electrode current collector 21a with a predetermined width and thickness, and positive electrode active material layers 21b containing a positive electrode active material formed on both sides thereof, except for an unformed portion 21a1 set at a constant width at one end of the width direction. A plurality of positive electrode tabs 21t are intermittently provided in the unformed portion 21a1 at predetermined positions along the longitudinal direction of the positive electrode sheet 21. Each of the plurality of positive electrode tabs 21t protrudes in the width direction of the positive electrode sheet 21. In this embodiment, the positions at which the plurality of positive electrode tabs 21t are provided are determined so that the positions of the plurality of positive electrode tabs 21t are aligned in a wound state.

[0015] For the positive electrode current collector 21a, a material having required resistance properties such as electrolyte resistance and oxidation resistance is used, taking into consideration the operating potential at the positive electrode. In lithium-ion secondary batteries, for example, aluminum or an aluminum alloy containing aluminum as the main material is generally used for the positive electrode current collector 21a. In the sheet-like positive electrode element 21, aluminum or an aluminum foil containing aluminum as the main material can be used for the positive electrode current collector 21a. For the positive electrode active material contained in the positive electrode active material layer 21b, a material that can release charge carriers during charging and absorb charge carriers during discharging is used.

[0016] For example, in the lithium-ion secondary battery 10, the positive electrode active material layer 21b releases lithium ions during charging and absorbs lithium ions during discharging. Examples of the positive electrode active material include lithium transition metal composite materials. Various positive electrode active materials other than lithium transition metal composite materials have been proposed, and unless otherwise specified, the positive electrode active material is not limited to lithium transition metal composite materials. The positive electrode active material layer 21b may be formed by applying and drying an electrode mixture slurry. In this embodiment, a positive electrode protective layer 21p is provided on the edge of the positive electrode active material layer 21b on the positive electrode current collector 21a (unformed portion 21a1). The positive electrode protective layer 21p is a layer that protects the unformed portion 21a1 and may be a layer containing an inorganic filler (e.g., alumina).

[0017] <Negative electrode sheet 22> The negative electrode sheet 22 has a negative electrode current collector 22a with a predetermined width and thickness, and a negative electrode active material layer 22b containing a negative electrode active material formed on both sides thereof, except for an unformed portion 22a1 set at a constant width on one edge in the width direction. In this embodiment, a plurality of negative electrode tabs 22t are intermittently provided in the unformed portion 22a1 at predetermined positions along the longitudinal direction of the negative electrode sheet 22. Each of the plurality of negative electrode tabs 22t protrudes in the width direction of the negative electrode sheet 22. In this embodiment, the positions at which the plurality of negative electrode tabs 22t are provided are determined so that the positions of the plurality of negative electrode tabs 22t are aligned in a wound state.

[0018] The negative electrode current collector 22a is made of a material having the required resistance properties, such as electrolyte resistance and oxidation resistance, taking into consideration the operating potential of the negative electrode. For example, in the lithium-ion secondary battery 10, copper or a copper alloy containing copper as the main material is generally used for the negative electrode current collector 22a. In the sheet-like negative electrode element 22, copper or a copper foil containing copper as the main material may be used for the negative electrode current collector 22a. The negative electrode active material contained in the negative electrode active material layer 22b is made of a material that can absorb charge carriers during charging and release the charge carriers during discharging. For example, in a lithium-ion secondary battery, a material such as natural graphite is used that can absorb lithium ions during charging and release the absorbed lithium ions during discharging. Generally, various negative electrode active materials have been proposed in addition to natural graphite, and the material is not particularly limited. The negative electrode active material layer 22b may be formed by, for example, applying a mixture of the negative electrode active material, a conductive material, a binder, and the like in a solvent, and then drying the mixture.

[0019] The separator sheets 31, 32 may be, for example, porous resin sheets that have the required heat resistance and allow electrolytes to pass through. Various separator sheets 31, 32 have been proposed, and there is no particular limitation. The separator sheets 31, 32 may have a functional layer, such as an adhesive layer or a heat-resistant layer (HRL), on the surface of a substrate made of a porous resin sheet. The heat-resistant layer is a layer containing, for example, an inorganic filler such as alumina, silica, boehmite, magnesia, or titania, and a binder such as PVdF. The heat-resistant layer may also serve as an adhesive layer.

[0020] Here, as shown in FIG. 3, the width Ln of the negative electrode active material layer 22b is formed wider than the width Lp of the positive electrode active material layer 21b, for example. The widths Ls of the separator sheets 31 and 32 are wider than the negative electrode active material layer 22b. That is, as shown in FIG. 3, Lp < Ln < Ls. The positive electrode sheet 21, the first separator sheet 31, the negative electrode sheet 22, and the second separator sheet 32 are aligned in the length direction and are stacked and wound in order. Here, the negative electrode active material layer 22b covers the positive electrode active material layer 21b with the separator sheets 31 and 32 interposed therebetween. The negative electrode active material layer 22b is covered with the separator sheets 31 and 32. The positive electrode tab 21t of the positive electrode current collector 21a and the negative electrode tab 22t of the negative electrode current collector 22a are provided so as to protrude from the separator sheets 31 and 32 in opposite directions in the width direction. The positive electrode protective layer 21p faces the edge of the negative electrode sheet 22 on the side opposite to the side where the negative electrode tab 22t is provided, via the separator sheets 31 and 32.

[0021] As shown in FIG. 2, the electrode body 20 is in a flat state along a plane including the winding axis WL (see FIG. 3) so as to be accommodated in the case body 41a of the case 41. Along the winding axis WL of the electrode body 20, the positive electrode tab 21t is disposed on one side and the negative electrode tab 22t is disposed on the opposite side. Here, as an example of the electrode body 20, a wound electrode body in which the positive electrode sheet 21, the first separator sheet 31, the negative electrode sheet 22, and the second separator sheet 32 are stacked and wound is illustrated. The configuration of the electrode body 20 is not limited to such a wound electrode body. Although not shown, the electrode body 20 may be, for example, a so-called laminated electrode body in which a positive electrode sheet and a negative electrode sheet having a predetermined shape are stacked with a separator sheet interposed therebetween.

[0022] <Case 41> As shown in FIG. 2, the case 41 houses the electrode assembly 20 and the electrolyte solution 15. The case 41 includes a case body 41a, which is a bottomed member having an opening 41a1 on one side opposite the bottom, and in this embodiment has a substantially rectangular parallelepiped shape with one side open. The sealing plate 41b is a plate material attached to the opening 41a1 of the case body 41a. In this embodiment, the case body 41a and the sealing plate 41b are each made of aluminum or an aluminum alloy mainly containing aluminum, from the perspectives of reducing weight and ensuring the required rigidity. Note that the case 41 may house multiple electrode bodies 20.

[0023] The electrolyte solution 15 is accommodated inside the case 41 together with the electrode assembly 20. A portion of the electrolyte solution 15 is impregnated into the electrode assembly 20. The electrolyte solution 15 is, for example, a non-aqueous electrolyte solution containing a non-aqueous solvent (organic solvent) and a supporting salt (electrolyte salt, such as a lithium salt or a sodium salt). Examples of non-aqueous solvents include carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. Examples of supporting salts include fluorine-containing lithium salts such as lithium hexafluorophosphate (LiPF6). The electrolyte solution 15 is typically liquid, but may also be gel-like. In addition, between the case 41 and the electrode assembly 20, there is surplus electrolyte solution 15a that has not completely impregnated the electrode assembly 20 and remains inside the case 41. In this embodiment, surplus electrolyte solution 15a is stored at both ends of the electrode assembly 20 in the long side direction X (gap GP1, described later). In the following description, unless otherwise specified, the term "electrolyte 15" includes "excess electrolyte 15a."

[0024] 4 is a longitudinal cross-sectional view of the lithium-ion secondary battery 10. As shown in FIG. 4, the electrode assembly 20 is in contact with the case 41 in the short side direction Y. In addition, the lower end of the electrode assembly 20 is located relatively close to the lower end of the case 41 in the height direction Z. Therefore, of the excess electrolyte 15a shown in FIG. 2, the portion located to the right of the electrode assembly 20 is relatively less likely to move leftward than the electrode assembly 20. Similarly, of the excess electrolyte 15a, the portion located to the left of the electrode assembly 20 is relatively less likely to move rightward than the electrode assembly 20.

[0025] <Case body 41a> As shown in Fig. 2, the case body 41a has a bottom surface portion 42 constituting a substantially rectangular bottom surface, a pair of wide surface portions 43 and 44 (see Fig. 1), and a pair of narrow surface portions 45 and 46. The bottom surface portion 42 is located below the electrode assembly 20 in the case 41 when viewed from the front of the lithium-ion secondary battery 10 shown in Fig. 2. In this embodiment, the bottom surface portion 42 is the surface facing the sealing plate 41b to which the positive electrode terminal 50 and the negative electrode terminal 60 are attached. The bottom surface portion 42 is located in a position facing a safety valve 41b3, which will be described later.

[0026] The pair of wide surface portions 43, 44 are an example of a pair of wide side surfaces in the present invention. The pair of narrow surface portions 45, 46 are an example of a pair of narrow side surfaces in the present invention. The pair of wide surface portions 43, 44 each rise from a long side of the bottom surface portion 42. The pair of narrow surface portions 45, 46 each rise from a short side of the bottom surface portion 42. An opening 41a1 surrounded by the pair of wide surface portions 43, 44 and the pair of narrow surface portions 45, 46 is formed on one side of the case body 41a.

[0027] As shown in FIG. 2, the case body 41a of the case 41 has a gap GP1 between the electrode assembly 20 and the pair of narrow surface portions 45, 46. In this embodiment, the gap GP1 is formed at both ends of the electrode assembly 20 in the long side direction X. The gap GP1 is a relatively wide gap between the case 41 and the electrode assembly 20. Also, as shown in FIG. 4, the pair of wide surface portions 43, 44 abut against the electrode assembly 20. In this embodiment, the electrode assembly 20 abuts against the pair of wide surface portions 43, 44 in the short side direction Y. Note that other components may be interposed between the electrode assembly 20 and the pair of wide surface portions 43, 44. For example, an insulating film covering the electrode assembly 20 may be interposed between the electrode assembly 20 and the pair of wide surface portions 43, 44. As shown in FIG. 2, in this embodiment, the portion of the bottom surface portion 42 located below the gap GP1 is defined as a perforated portion 42a. Although details will be described later, the perforation portions 42a are portions that make holes for recovering the electrolyte solution 15. In this embodiment, the perforation portions 42a are provided on both ends of the electrode body 20. A method for recovering the electrolyte solution 15 will be described later.

[0028] <Sealing plate 41b> The sealing plate 41b is a lid attached to the opening 41a1 of the case body 41a that houses the electrode assembly 20. In this embodiment, as shown in FIG. 1, the sealing plate 41b is rectangular in plan view. The outer surface 41ba forms the upper surface of the sealing plate 41b. In this embodiment, the outer surface 41ba is provided with a liquid inlet 41b1 and a safety valve 41b3. The liquid inlet 41b1 is closed by attaching a sealing member 41b2 after the sealing plate 41b is attached to the opening 41a1 of the case body 41a and the electrolyte solution 15 is injected into the case body 41a. Note that FIG. 2 shows the state in which the sealing plate 41b is assembled to the opening 41a1 of the case body 41a and welded. In FIG. 2, the sealing member 41b2 is not attached to the sealing plate 41b. The safety valve 41b3 is thin-walled and breaks when the pressure inside the case 41 exceeds a predetermined value. In this embodiment, the safety valve 41b3 is designed to rupture when the pressure inside the case 41 reaches 1.4 MPa or higher. However, the pressure at which the safety valve 41b3 ruptures is not limited to this. The sealing plate 41b forms the top surface of the lithium-ion secondary battery 10, but is not limited to this. For example, the opening 41a1 and the sealing plate 41b may be provided as a pair in the long side direction.

[0029] As shown in FIG. 2, the sealing plate 41b is fitted with a positive electrode terminal 50 and a negative electrode terminal 60 connected to the electrode assembly 20. The positive electrode terminal 50 and the negative electrode terminal 60 are examples of current collector terminal components. The positive electrode terminal 50 includes an external terminal 51 and an internal terminal 55. The negative electrode terminal 60 includes an external terminal 61 and an internal terminal 65. The internal terminals 55, 65 are each attached to the inside of the sealing plate 41b via an insulator 80. The external terminals 51, 61 are each attached to the outside of the sealing plate 41b via a gasket 70. The internal terminals 55, 65 each extend into the case body 41a. The unformed portion 21a1 of the positive electrode current collector 21a and the unformed portion 22a1 of the negative electrode current collector 22a of the electrode assembly 20 are attached to internal terminals 55, 65 attached to both long side portions of the sealing plate 41b.

[0030] The internal terminals 55, 65 are made of metal. For example, aluminum or an aluminum alloy may be used as the positive electrode internal terminal 55 in order to improve the bonding strength with the positive electrode tab 21t. For example, copper or a copper alloy may be used as the negative electrode internal terminal 65 in order to improve the bonding strength with the negative electrode tab 22t and because it has the required resistance such as electrolyte resistance and oxidation resistance.

[0031] The external terminals 51, 61 are made of metal. The metal used for the external terminals 51, 61 is appropriately selected depending on the type of external connection component, such as a bus bar. Examples of materials that can be used for the external terminals 51, 61 include aluminum, aluminum alloys, copper, and copper alloys. The external terminals 51, 61 may be formed by joining multiple metals together using dissimilar metal joining. Although not shown, a mounting hole is formed in the sealing plate 41b. An insulator 80 is attached to the inside of the mounting hole, and a gasket 70 is attached to the outside of the sealing plate 41b. One of the internal terminals 55, 65 and the external terminals 51, 61 has a shaft, which is inserted into the mounting hole with the gasket 70 and the insulator 80 interposed therebetween. The internal terminals 55, 65 and the external terminals 51, 61 are joined by the shaft inserted into the mounting hole.

[0032] The gasket 70 and the insulator 80 are preferably made of a material having excellent chemical resistance and weather resistance. In this embodiment, the gasket 70 is made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA). The material used for the gasket 70 is not limited to PFA. For example, polypropylene (PP), polyethylene (PE), polyphenylene sulfide resin (PPS), etc. may be used for the gasket 70. The insulator 80 is made of polyphenylene sulfide resin (PPS). The material used for the insulator 80 is not limited to PPS.

[0033] During manufacturing, the lithium-ion secondary battery 10 has the positive electrode terminal 50 and the negative electrode terminal 60 attached to the sealing plate 41b with the gasket 70 and the insulator 80 attached to the sealing plate 41b. Next, the positive electrode tab 21t is joined to the internal terminal 55 of the positive electrode terminal 50, and the negative electrode tab 22t is joined to the internal terminal 65 of the negative electrode terminal 60, thereby attaching the electrode body 20 to the sealing plate 41b. Next, the electrode body 20 is inserted into the case body 41a from the opening 41a1, and the sealing plate 41b is attached to the opening 41a1 (see FIG. 1) of the case body 41a. At this time, the winding axis WL (see FIG. 3) of the electrode body 20 is arranged along the long side direction X of the case body 41a. The positive electrode tab 21t of the electrode body 20 faces the narrow surface portion 45. The negative electrode tab 22t faces the narrow surface portion 46. 2, the peripheral edge of sealing plate 41b is joined to the edge of opening 41a1 of case body 41a. This joining may be achieved, for example, by continuous welding without any gaps. This welding may be achieved, for example, by laser welding.

[0034] Various structures can be employed for the internal terminals 55, 65, the external terminals 51, 61, the gasket 70, and the insulator 80. For example, the internal terminals 55, 65, the external terminals 51, 61, the gasket 70, and the insulator 80 may have an appropriate structure depending on the structure of the electrode assembly 20 to be housed. In addition, one of the positive electrode terminal 50 and the negative electrode terminal 60 may be provided with a mechanism (CID (Current Interrupt Device)) that interrupts current when internal pressure increases due to gas generated therein during overcharge.

[0035] Incidentally, the inventors of the present application would like to efficiently recover the electrolyte solution 15 when an electricity storage device, such as this lithium ion secondary battery 10, in which the electrode body 20 and the electrolyte solution 15 are accommodated inside the case 41 is discarded. A method for efficiently recovering the electrolyte solution 15 from the lithium ion secondary battery 10 has not yet been established.

[0036] Fig. 5 is a schematic diagram showing the electrolyte solution recovery device 100. Fig. 6 is a flowchart showing the procedure for recovering the electrolyte solution 15.

[0037] The method for recovering an electrolyte solution from an electricity storage device proposed here includes an installation step S2 and a hole-making step S3, as shown in Fig. 6. The installation step S2 is a step of installing the electricity storage device inside a sealed chamber 110 (see Fig. 5). In the installation step S2, a lithium-ion secondary battery 10 serving as the electricity storage device is installed in a predetermined position in a predetermined orientation. In the hole-making step S3, the pressure inside the chamber 110 is reduced, and a hole is made in the reduced-pressure atmosphere in the lower part (bottom surface portion 42 in the example shown in Fig. 5) of the case 41 installed inside the chamber 110 in the installation step S2.

[0038] Here, the lower part of case 41 is determined by the attitude of the electricity storage device when holes are drilled in hole drilling step S3. Here, the lower part of case 41 is a portion of case 41 of the electricity storage device that faces downward when holes are drilled in hole drilling step S3.

[0039] According to this electrolyte recovery method, the interior of the chamber 110 is depressurized, and a hole is drilled in the lower part (bottom surface 42) of the case 41 installed inside the chamber 110 in the installation step S2 in the depressurized atmosphere. Therefore, when the hole is drilled in the lower part (bottom surface 42) of the case 41, the pressure inside the case 41 is higher than the pressure outside the case 41. Furthermore, when the hole is drilled in the lower part of the case 41, excess electrolyte 15a accumulates around the hole. Therefore, the pressure difference between the pressure inside the case 41 and the pressure outside the case 41 allows the excess electrolyte 15a accumulated in the lower part of the case 41 to be efficiently discharged to the outside (inside the chamber 110). Furthermore, at this time, if the electrode assembly 20 is impregnated with the electrolyte 15 (excluding the excess electrolyte 15a), the gas accumulated in the space partitioned by the electrolyte 15 inside the electrode assembly 20 may be maintained at a high pressure. After the excess electrolyte 15a accumulated in the lower part of the case 41 is discharged, the inside of the case 41 is reduced in pressure to the same level as the inside of the chamber 110. The electrolyte 15 impregnated in the electrode body 20 is pushed out of the electrode body 20 by the gas accumulated in the space partitioned by the electrolyte 15 inside the electrode body 20, and is discharged into the case 41. The electrolyte 15 discharged into the case 41 is discharged from the hole opened in the lower part of the case 41. In this way, according to the electrolyte recovery method proposed here, the electrolyte 15 impregnated in the electrode body 20 is also efficiently recovered.

[0040] The device that embodies the electrolyte recovery method and the electrolyte recovery method will be described in more detail below.

[0041] FIG. 5 is a schematic diagram showing an electrolyte solution recovery apparatus 100 according to the first embodiment. In FIG. 5, up, down, left, and right are represented by U, D, L, and R, respectively. Note that up, down, left, and right are merely directions for convenience of explanation and do not limit the installation mode of the electrolyte solution recovery apparatus 100. Although not shown, the direction perpendicular to the up-down direction of the electrolyte solution recovery apparatus 100 (hereinafter simply referred to as the "up-down direction") and the left-right direction of the electrolyte solution recovery apparatus 100 (hereinafter simply referred to as the "left-right direction") is referred to as the front-rear direction of the electrolyte solution recovery apparatus 100 (hereinafter simply referred to as the "front-rear direction"). As shown in FIG. 5, the electrolyte solution recovery apparatus 100 includes a chamber 110, a vacuum pump 120, an open valve 130, and a control device 180. The chamber 110 includes a table 140, an elevating device 150, and a hole-making device 160. The electrolyte recovery device 100 is a device in which a lithium ion secondary battery 10 is installed and which recovers the electrolyte 15.

[0042] The chamber 110 comprises a chamber lid 111 and a chamber body 112. The chamber lid 111 and the chamber body 112 are configured to be openable and closable. When the chamber lid 111 and the chamber body 112 are closed, the chamber 110 is configured to be airtight. Note that the chamber 110 may be provided with, for example, an openable and closable flow channel in the bottom surface 112D of the chamber body 112. The flow channel may be configured to enable recovery of liquid or the like inside the chamber 110.

[0043] The table 140 is a platform on which the lithium-ion secondary battery 10 is placed. The table 140 has a plate-like shape extending in the left-right and front-rear directions. Although not shown, the table 140 is configured to be able to fix the lithium-ion secondary battery 10. The method for fixing the lithium-ion secondary battery 10 is not particularly limited, but the lithium-ion secondary battery 10 may be fixed, for example, by a vice that is openable and closable in the front-rear or left-right directions. Note that the left-right length of the table 140 in this embodiment is shorter than the length of the lithium-ion secondary battery 10 in the long side direction X.

[0044] The lifting device 150 is a device that lifts and lowers the table 140. In this embodiment, the lifting device 150 includes a servo motor 151 and a ball screw 152. One end of the ball screw 152 is connected to the lower end of the table 140, and the other end is connected to the servo motor 151. The servo motor 151 is electrically connected to and controlled by the control device 180. When the control device 180 drives the servo motor 151, the protruding length of the ball screw 152 changes. When the protruding length of the ball screw 152 changes, the vertical position of the table 140 connected to the ball screw 152 changes. In this embodiment, the lower end of the ball screw 152 is located below a mounting plate 162, which will be described later. The number of servo motors 151 and ball screws 152 included in the lifting device 150 is not particularly limited.

[0045] The drilling device 160 is disposed below the table 140. The drilling device 160 includes a protruding pin 161 and an installation plate 162. In this embodiment, the protruding pin 161 is disposed directly below the drilling portion 42a. That is, two protruding pins 161 are disposed side by side along the long side direction X of the lithium ion secondary battery 10. The protruding pins 161 are an example of a drilling tool according to the present invention. The protruding pins 161 have a sharply pointed shape facing upward. Therefore, the protruding pins 161 are configured to be able to pierce the case 41. In this embodiment, the protruding pins 161 are formed from resin. Therefore, even if the protruding pins 161 pierce the case main body 41a, a short circuit does not occur in the electrode body 20 of the lithium ion secondary battery 10. However, the material for forming the protruding pins 161 is not limited to this.

[0046] The mounting plate 162 is a plate on which the protruding pin 161 is mounted. The mounting plate 162 has a hole (not shown) formed therein that is larger than the outer diameter of the ball screw 152 in a plan view, and the ball screw 152 is inserted into the hole. Therefore, even if the protruding length of the ball screw 152 changes, the mounting plate 162 does not move. The shape of the mounting plate 162 is not particularly limited, but it extends, for example, in the left-right and front-rear directions. That is, the mounting plate 162 has a substantially rectangular shape in a plan view. Furthermore, the material from which the mounting plate 162 is formed is not particularly limited.

[0047] The vacuum pump 120 is connected to the chamber 110. The vacuum pump 120 is configured to reduce the pressure inside the chamber 110. Although not shown, a valve or the like may be provided between the chamber 110 and the vacuum pump 120. The vacuum pump 120 is electrically connected to the control device 180 and is controlled by the control device 180.

[0048] Because the chamber 110 is configured to ensure airtightness, when the vacuum pump 120 is driven, the inside of the chamber 110 is reduced in pressure. Here, a reduced pressure state refers to a state of pressure lower than atmospheric pressure, and includes a vacuum state. In this embodiment, when the vacuum pump 120 is driven, the inside of the chamber 110 is reduced in pressure. As described above, the case 41 of the lithium-ion secondary battery 10 is sealed. Therefore, even if the inside of the chamber 110 is reduced in pressure by the vacuum pump 120, the inside of the case 41 is not reduced in pressure. Therefore, in the following description, unless otherwise specified, the "inside of the chamber 110" does not include the space inside the case 41.

[0049] The release valve 130 is connected to the chamber 110. In this embodiment, the release valve 130 is connected to the chamber cover 111. However, the release valve 130 may also be connected to the chamber main body 112. The release valve 130 is a valve that is configured to be openable and closable. When the release valve 130 is opened, the inside of the chamber 110 is connected to the outside of the chamber 110. Therefore, the inside of the chamber 110 is open to the atmosphere. The release valve 130 is electrically connected to the control device 180, and its opening and closing is controlled by the control device 180.

[0050] The control device 180 controls the vacuum pump 120, the release valve 130, and the servo motor 151. The configuration of the control device 180 is not particularly limited. The control device 180 is, for example, a microcomputer. The hardware configuration of the microcomputer is not particularly limited, but may include, for example, an interface (I / F), a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a storage device.

[0051] The above has described the electrolyte solution recovery device 100 according to this embodiment. Next, a description will be given of the steps for recovering the electrolyte solution 15 of the lithium ion secondary battery 10 using the electrolyte solution recovery device 100. Fig. 6 is a flowchart showing the procedure for recovering the electrolyte solution 15.

[0052] The preparation step S1 is a step of preparing a lithium ion secondary battery 10 (electricity storage device) in which an electrode assembly 20 and an electrolyte solution 15 are accommodated inside a case 41. In the preparation step S1, for example, a used lithium ion secondary battery 10 is prepared. Note that the lithium ion secondary battery 10 has a sealed case 41 as described above. At this time, the pressure inside the case 41 is equivalent to atmospheric pressure.

[0053] The installation step S2 is a step of installing the lithium ion secondary battery 10 (electricity storage device) inside the sealed chamber 110. In the installation step S2, an operator opens the chamber lid 111 of the chamber 110 and installs the lithium ion secondary battery 10 on the table 140. In this embodiment, the lithium ion secondary battery 10 is arranged in a direction such that the left-right direction of the electrolyte solution recovery apparatus 100 coincides with the long side direction X of the lithium ion secondary battery 10 and the up-down direction of the electrolyte solution recovery apparatus 100 coincides with the height direction Z of the lithium ion secondary battery 10. At this time, the pair of wide surface portions 43, 44 and the pair of narrow surface portions 45, 46 of the lithium ion secondary battery 10 are installed so as to be approximately perpendicular to the table 140. Therefore, in the installation step S2, the operator installs the lithium ion secondary battery 10 so that the pair of wide surface portions 43, 44 and the pair of narrow surface portions 45, 46 are approximately perpendicular to the installation surface of the electrolyte solution recovery apparatus 100. That is, the worker places the lithium-ion secondary battery 10 inside the chamber 110 so that the sealing plate 41b is located on the upper surface in the height direction Z. The position of the lithium-ion secondary battery 10 in the long side direction X is determined so that the protruding pin 161 is located directly below the hole 42a. After the lithium-ion secondary battery 10 is placed, the chamber lid 111 is attached to the chamber main body 112. This places the lithium-ion secondary battery 10 inside the chamber 110, and the chamber 110 is sealed.

[0054] The hole drilling process S3 is a process of reducing the pressure inside the chamber 110 and drilling holes in the hole drilling portion 42a of the case 41 installed inside the chamber 110 in the installation process S2 in the reduced pressure atmosphere. In the hole drilling process S3, the portions to drill holes are set in the lower part of the case 41 where the gap between the case 41 and the electrode assembly 20 is wide. In this embodiment, holes are drilled at positions below the gaps GP1 (see FIG. 5 ) formed between the electrode assembly 20 and the pair of narrow surface portions 45, 46. In the hole drilling process S3 of this embodiment, the protruding pin 161 is pressed against the hole drilling portion 42a of the case 41. In the hole drilling process S3, first, the control device 180 closes the release valve 130. In this state, the control device 180 drives the vacuum pump 120. This reduces the pressure inside the chamber 110. In this embodiment, the vacuum pump 120 reduces the pressure inside the chamber 110 until a vacuum is reached. It should be noted that, since the case 41 of the lithium ion secondary battery 10 is sealed, even if the inside of the chamber 110 is evacuated, the pressure inside the case 41 is maintained at a pressure equivalent to atmospheric pressure.

[0055] After the inside of the chamber 110 is evacuated, the control device 180 drives the servo motor 151. The control device 180 drives the servo motor 151 in a direction that shortens the protruding length of the ball screw 152 from the state shown in FIG. 5. That is, the control device 180 moves the table 140 downward. In the installation step S2, the protruding pin 161 was positioned directly below the hole drilling portion 42a, so when the table 140 is moved downward, the protruding pin 161 comes into contact with the hole drilling portion 42a. When the table 140 is further moved downward, the protruding pin 161 penetrates the hole drilling portion 42a.

[0056] FIG. 7 is an enlarged view of the vicinity of the protruding pin 161 when the protruding pin 161 penetrates the perforation portion 42a. As shown in FIG. 7, a through hole h is formed in the perforation portion 42a, penetrating the vertical direction. At this time, excess electrolyte 15a flows out through the through hole h. Furthermore, the formation of the through hole h connects the internal space of the case 41 with the internal space of the chamber 110. As described above, the internal pressure of the case 41 is equal to atmospheric pressure, and the interior of the chamber 110 is in a vacuum state. Therefore, a pressure difference occurs between the internal pressure of the case 41 and the internal pressure of the chamber 110. Because the internal pressure of the case 41 is higher than the internal pressure of the chamber 110, the electrolyte 15 impregnated in the electrode assembly 20 inside the case 41 flows out into the gap GP1, passes through the through hole h, and flows out of the case 41. When the pressure difference between the internal pressure of the case 41 and the internal pressure of the chamber 110 disappears, the outflow of the electrolyte 15 impregnated in the electrode assembly 20 stops. The outflowing electrolyte 15 accumulates on the bottom surface 112D of the chamber main body 112 (see FIG. 5).

[0057] After the hole-making step S3, the release valve 130 is opened. As a result, the pressure inside the chamber 110 and inside the case 41 becomes equal to atmospheric pressure. Furthermore, by opening the openable and closable flow path provided in the chamber 110, the electrolyte solution 15 accumulated in the bottom portion 112D can be collected. After the electrolyte solution 15 is collected, the lithium-ion secondary battery 10 is removed from the chamber 110 and recycled as appropriate. Note that in the series of steps shown in FIG. 6, the pressure inside the chamber 110 and inside the case 41 is equal to or lower than atmospheric pressure. Furthermore, as described above, the safety valve 41b3 (see FIG. 1) ruptures when the pressure inside the case main body 41a becomes equal to or higher than 1.4 MPa. Therefore, in the series of steps shown in FIG. 6, the safety valve 41b3 (see FIG. 1) of the lithium-ion secondary battery 10 is not opened.

[0058] In the embodiment described above, in the hole-making step S3, a hole-making portion 42a is set as a portion of the lower part of the case 41 where a hole is to be made. The hole-making portion 42a is located below the gap GP1. The gap GP1 is a relatively wide portion of the gap between the case 41 and the electrode body 20. Excess electrolyte 15a is stored in the gap GP1. Therefore, by passing the protruding pin 161 through the hole-making portion 42a, the excess electrolyte 15a can be efficiently discharged and collected from the through-hole h.

[0059] In the embodiment described above, the chamber 110 includes the protruding pin 161. In the hole making step S3, the bottom surface portion 42 of the case 41 is pressed against the protruding pin 161 to form a through hole h, thereby enabling the recovery of the electrolyte solution 15. Therefore, the electrolyte solution 15 can be recovered simply by pressing the protruding pin 161. This allows the recovery of the electrolyte solution 15 with a relatively simple configuration.

[0060] In the embodiment described above, the chamber 110 is provided with a protruding pin 161 as a hole-making tool. The protruding pin 161 forms a through hole h in the hole-making portion 42a of the bottom surface portion 42. This makes it possible to form the through hole h in the case 41 with a relatively simple configuration compared to, for example, drilling a hole in the case 41 with a laser cutter or the like.

[0061] In the embodiment described above, the case 41 has a pair of wide surface portions 43, 44 and a pair of narrow surface portions 45, 46. A gap GP1 is formed between the case 41 and the pair of narrow surface portions 45, 46. The case 41 and the pair of wide surface portions 43, 44 abut against each other. In the perforation step S3, a through hole h is formed in the perforation portion 42a located below the gap GP1. This allows the recovery of the electrolyte solution 15 even when a rectangular lithium-ion secondary battery 10 is used as the electricity storage device, as in this embodiment.

[0062] In the above-described embodiment, in the installation step S2, the lithium-ion secondary battery 10 is installed so that the pair of wide surface portions 43, 44 and the pair of narrow surface portions 45, 46 are approximately perpendicular to the installation surface. Furthermore, through-holes h are formed in the perforated portions 42a below the gaps GP1 formed at both ends of the electrode body 20. Here, depending on the dimensions of the electrode body 20 and the case 41, excess electrolyte 15a arranged in one gap GP1 of the electrode body 20 in the long side direction X may not easily move to the other gap GP1 of the electrode body 20. In cases such as the present embodiment where the pair of wide surface portions 43, 44 are in contact with the case 41, the movement of excess electrolyte 15a may be restricted. However, as in the present embodiment, when the lithium ion secondary battery 10 is placed so that the pair of wide surface portions 43, 44 and the pair of narrow surface portions 45, 46 are substantially perpendicular to the placement surface and the through-hole h is formed in the perforation portion 42a, the excess electrolyte 15a can flow out without moving in the long side direction X. Therefore, since the pair of wide surface portions 43, 44 and the pair of narrow surface portions 45, 46 are substantially perpendicular to the placement surface, the excess electrolyte 15a can be more efficiently collected.

[0063] In the above-described embodiment, the case 41 includes the opening 41a1, the sealing plate 41b, the positive electrode terminal 50, and the negative electrode terminal 60. In the installation step S2, the lithium ion secondary battery 10 is placed inside the chamber 110 so that the sealing plate 41b is placed on the upper surface. At this time, the positive electrode terminal 50 and the negative electrode terminal 60 are placed on the upper surface of the lithium ion secondary battery 10. Here, for example, if the positive electrode terminal 50 and the negative electrode terminal 60 are placed near the lower end of the lithium ion secondary battery 10, the positive electrode terminal 50 and the negative electrode terminal 60 may prevent the electrolyte 15 from leaking out. Therefore, since the positive electrode terminal 50 and the negative electrode terminal 60 are placed on the upper surface, the electrolyte 15 is more likely to leak out of the lithium ion secondary battery 10.

[0064] In the above-described embodiment, the protruding pin 161 is provided as the hole-making tool, but this is not limiting. The hole-making tool may be, for example, a cutting tool that cuts the lower part of the case 41. The cutting tool may be, for example, an end mill or the like. For example, the lower part of the case 41 (hole-making portion 42a) can be cut by three-dimensionally changing the positional relationship between the cutting tool and the lithium-ion secondary battery 10 using a driving device that moves the position of the cutting tool. Even in such a case, as in the above-described embodiment, the electrolyte 15 can be recovered with a relatively simple configuration.

[0065] The above-described embodiment is merely one example of the electrolyte recovery method disclosed herein. The technology disclosed herein can be embodied in various other forms. Other embodiments of the technology disclosed herein will be described below.

[0066] Second Embodiment In the first embodiment described above, a rectangular lithium ion secondary battery 10 is used as the power storage device, but the invention is not limited to this. The power storage device may be, for example, a cylindrical lithium ion secondary battery.

[0067] Fig. 8 is a diagram showing an electrolyte solution recovery apparatus 100B according to a second embodiment. In the electrolyte solution recovery apparatus 100B shown in Fig. 8, a cylindrical lithium ion secondary battery 10B is disposed inside a chamber 110. In the second embodiment, the same reference numerals are used for members and parts that have the same functions as those in the first embodiment, and duplicated descriptions will be omitted or simplified as appropriate.

[0068] The lithium ion secondary battery 10B includes a case 41B and an electrode assembly 20B. The case 41B has a substantially cylindrical shape. The case 41B includes a cylindrical case body 41Ba with a bottom and a lid 41Bb. The case body 41Ba and the lid 41Bb are both made of metal and are insulated from each other. The axial direction of the case 41B is substantially perpendicular to the left-right direction of the electrolyte solution recovery device 100B. The electrode assembly 20B is formed by winding a positive electrode sheet 21 (see FIG. 3), a negative electrode sheet 22 (see FIG. 3), and separator sheets 31 and 32 (see FIG. 3) into a cylindrical shape. The electrode assembly 20B is in contact with the case 41B in the radial direction. The positive electrode current collector 21a and the negative electrode current collector 22a of the electrode assembly 20B are electrically connected to the lid 41Bb and the case body 41Ba, respectively.

[0069] A gap GP2 is formed in the radial center of the cylindrically wound electrode body 20B. The gap GP2 is formed between the electrode body 20B and the case 41B in the radial direction of the case 41B. Therefore, excess electrolyte 15a is stored in the gap GP2 of the case main body 41Ba. Here, the portion of the case main body 41Ba located below the excess electrolyte 15a is defined as a perforated portion 42aB. A protruding pin 161 is disposed directly below the perforated portion 42aB. In the table 140 of this embodiment, a hole 141 is formed at a position that does not overlap with the protruding pin 161 in a plan view.

[0070] As in the first embodiment, in the installation step S2 (see FIG. 6), the lithium ion secondary battery 10B is installed on the table 140. In the installation step S2, as shown in FIG. 8, the lithium ion secondary battery 10B is installed so that the axial direction of the case 41B is approximately perpendicular to the installation surface.

[0071] As in the first embodiment, in the hole making step S3 (see FIG. 6), a hole can be made in the hole making portion 42aB by lowering the table 140. When a hole is made in the hole making portion 42aB, excess electrolyte 15a and the electrolyte 15 impregnated in the electrode body 20 flow out of the case 41B.

[0072] As described above, according to the electrolyte recovery method of this embodiment, the electrolyte 15 can be recovered more efficiently even from a cylindrical lithium ion secondary battery 10B (electricity storage device), as in the first embodiment.

[0073] According to the electrolyte solution recovery method of the present embodiment, the axial direction of the case body 41Ba is approximately perpendicular to the installation surface of the electrolyte solution recovery device 100B. Therefore, compared to when the case body 41Ba is inclined, for example, the electrolyte solution 15 flows out more easily from the perforated portion 42bB.

[0074] The invention disclosed herein has been described in various ways. Unless otherwise specified, the embodiments described herein do not limit the present invention. Furthermore, the embodiments of the invention disclosed herein can be modified in various ways, and each component and each process described herein can be omitted or combined as appropriate, unless a particular problem arises.

[0075] As described above, this specification includes the disclosures set forth in the following sections.

[0076] Section 1: preparing an electricity storage device in which an electrode assembly and an electrolyte are housed inside a case; an installation step of installing the electricity storage device inside a sealed chamber; a step of reducing the pressure inside the chamber, and drilling a hole in the lower part of the case installed inside the chamber in the installation step in the reduced pressure atmosphere; A method for recovering an electrolyte from an electricity storage device, comprising:

[0077] Section 2: Item 2. The electrolyte recovery method according to item 1, wherein in the step of drilling a hole, the hole is drilled in a portion of the lower part of the case where the gap between the case and the electrode body is large.

[0078] Section 3: the chamber includes a punching tool; Item 3. The method for recovering an electrolyte from an electricity storage device according to item 1 or 2, wherein in the step of drilling a hole, the drilling tool is pressed against a lower portion of the case.

[0079] Section 4: Item 4. The method for recovering electrolyte from an electricity storage device according to Item 3, wherein the hole-making tool is a protruding pin that can be pierced into the case.

[0080] Section 5: the chamber includes a cutting tool capable of cutting the case; Item 3. The method for recovering an electrolyte from an electricity storage device according to item 1 or 2, wherein the step of drilling a hole involves cutting a predetermined position on a lower portion of the case with the cutting tool.

[0081] Item 6: the case having a pair of wide sides and a pair of narrow sides; the case has a gap between the electrode body and each of the pair of narrow side surfaces, The pair of wide side surfaces abut against the electrode body, 6. The method for recovering an electrolyte from an electricity storage device according to any one of items 1 to 5, wherein the step of drilling holes drills holes in the case at positions below the gaps formed between the electrode body and each of the pair of narrow side surfaces.

[0082] Section 7: Item 7. The method for recovering an electrolyte solution from an electricity storage device according to Item 6, wherein the step of installing the electricity storage device installs the electricity storage device so that the pair of wide side surfaces and the pair of narrow side surfaces are substantially perpendicular to an installation surface.

[0083] Section 8: The case is Opening and a lid that closes the opening; a terminal member attached to the lid and the electrode body, Item 8. The method for recovering an electrolyte solution from an electricity storage device according to Item 6 or 7, wherein the placing step places the case inside the chamber so that the lid is placed on an upper surface.

[0084] Section 9: The case has a substantially cylindrical shape, 6. The method for recovering an electrolyte solution from an electricity storage device according to any one of items 1 to 5, wherein the gap is formed between the electrode body and the case in the radial direction of the case.

[0085] Section 10: Item 10. The method for recovering an electrolyte solution from an electricity storage device according to Item 9, wherein the installation step installs the electricity storage device so that the axial direction of the case is approximately perpendicular to an installation surface. [Explanation of symbols]

[0086] 10,10B Lithium-ion secondary battery 15,15a Electrolyte 20,20B electrode body 21 Positive electrode element (positive electrode sheet) 21a Positive electrode current collector 21a1,22a1 Unformed part 21b Positive electrode active material layer 21p positive electrode protective layer 21t Positive electrode tab 22 Negative electrode element (negative electrode sheet) 22a Negative electrode current collector 22b Negative electrode active material layer 22t negative electrode tab 31,32 Separator sheet 41,41B Case 41Bb Lid body 41a, 41B1 Case body 41a1 opening 41b Sealing plate 41b1 Liquid injection hole 41b2 Sealing member 41b3 Safety valve 41ba outer surface 42 Bottom part 42a, 42aB hole drilling section 43,44 Wide surface section 45,46 Narrow side part 50 Positive terminal 51,61 External terminals 55,65 Internal terminal 60 Negative terminal 70 Gasket 80 insulator 100,100B Electrolyte recovery device 110 Chamber 111 Chamber lid 112 Chamber body 112D bottom part 120 Vacuum Pump 130 Release Valve 140 tables 141 holes 150 Lifting device 151 Servo motor 152 Ball screw 160 equipment 161 Protruding pin 162 Installation plate 180 Control Device GP1, GP2 gap S1 Preparation process S2 installation process S3 Drilling process WL winding shaft X long side direction Y Short side direction Z height direction h Through hole

Claims

1. preparing an electricity storage device in which an electrode assembly and an electrolyte are housed inside a case; an installation step of installing the electricity storage device inside a sealed chamber; a step of reducing the pressure inside the chamber, and drilling a hole in the lower part of the case installed inside the chamber in the installation step in the reduced pressure atmosphere; A method for recovering an electrolyte from an electricity storage device, comprising:

2. 2. The electrolyte recovery method according to claim 1, wherein in the hole drilling step, the hole drilling location is set to a location in the lower part of the case where the gap between the case and the electrode body is wide.

3. the chamber includes a punching tool; The method for recovering electrolyte from an electricity storage device according to claim 1 , wherein in the hole drilling step, the hole drilling tool is pressed against a lower portion of the case.

4. The method for recovering electrolyte from an electricity storage device according to claim 3 , wherein the hole-making tool is a protruding pin that can be pierced into the case.

5. the chamber includes a cutting tool capable of cutting the case; The method for recovering electrolyte from an electricity storage device according to claim 1 , wherein the step of drilling a hole comprises cutting a predetermined position on the bottom of the case with the cutting tool.

6. the case having a pair of wide sides and a pair of narrow sides; the case has a gap between the electrode body and each of the pair of narrow side surfaces, The pair of wide side surfaces abut against the electrode body, 2. The method for recovering electrolyte from an electricity storage device according to claim 1, wherein the step of drilling holes drills holes in the case at positions below the gaps formed between the electrode body and each of the pair of narrow side surfaces.

7. The method for recovering electrolyte from an electricity storage device according to claim 6 , wherein the installing step installs the electricity storage device so that the pair of wide side surfaces and the pair of narrow side surfaces are substantially perpendicular to an installation surface.

8. The case is Opening and a lid that closes the opening; a terminal member attached to the lid and the electrode body, The method for recovering electrolyte from an electricity storage device according to claim 6 , wherein the placing step includes placing the case inside the chamber so that the lid is placed on an upper surface thereof.

9. The case has a substantially cylindrical shape, The method for recovering electrolyte from an electricity storage device according to claim 1 , wherein the gap is formed between the electrode body and the case in a radial direction of the case.

10. The method for recovering electrolyte from an electricity storage device according to claim 9 , wherein the step of installing the electricity storage device includes installing the electricity storage device so that an axial direction of the case is substantially perpendicular to an installation surface.

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