PROCESSING METHOD FOR BATTERY

The present disclosure provides a processing method for a battery including an exterior body and an electrode body. The exterior body includes a case main body including a bottom wall, an opening that faces the bottom wall, and side walls that extend from the bottom wall to the opening, and a lid body that seals the opening of the case main body. This processing method includes a cutting step of, when a posture in which the lid body is positioned directly above in a vertical direction and the side walls extend along the vertical direction is defined as a normal posture, cutting the exterior body in a posture other than the normal posture along the opening.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Japanese Patent Application No. 2022-175523 filed on Nov. 1, 2022. The entire contents of this application are hereby incorporated herein by reference.

BACKGROUND OF THE DISCLOSURE

The present disclosure relates to a processing method for a battery.

A battery typically includes an exterior body and an electrode body accommodated in the exterior body. The exterior body includes a case main body including a bottom wall, an opening that faces the bottom wall, and side walls that extend from the bottom wall to the opening, and a lid body that seals the opening of the case main body. The exterior body is unified in a manner that the lid body is joined (for example, joined by welding) to a periphery of the opening of the case main body.

In order to reduce wastes and use resources effectively, used batteries are conventionally collected and recycled. In regard to this, for example, Japanese Patent No. 7120578 describes that a part joined by welding between a case main body and a lid body is cut by end mill machining or laser irradiation, an electrode body is extracted from the case main body, and a valuable metal such as Ni or Co is collected as a resource.

SUMMARY

According to examinations by the present inventor, however, when the exterior body is opened by the end mill machining or the laser irradiation, a foreign substance such as cutting trash is easily mixed into the case main body from a cutting opening surface if the exterior body is cut along the opening in a normal posture in which the lid body is positioned directly above in a vertical direction and the side walls extend along the vertical direction. As a result, the ignition due to short-circuiting between positive and negative electrodes of the electrode body may occur.

The present disclosure has been made in view of the above circumstances and a main object of the present disclosure is to provide a processing method for a battery in which a foreign substance is not easily mixed into a case main body when an exterior body is opened.

The present disclosure provides a processing method for a battery that includes an exterior body and an electrode body accommodated in the exterior body, and the exterior body includes: a case main body including a bottom wall, an opening that faces the bottom wall, and side walls that extend from the bottom wall to the opening; and a lid body that seals the opening of the case main body. The processing method includes a cutting step of, when a posture in which the lid body is positioned directly above in a vertical direction and the side walls extend along the vertical direction is defined as a normal posture, cutting the exterior body in a posture other than the normal posture along the opening.

In a conventional method in which the exterior body is cut in the normal posture, since a cutting opening surface faces directly upward, cutting trash is easily mixed into the case main body. By contrast, when the exterior body is cut along the opening in the posture other than the normal posture, mixing of a foreign substance such as cutting trash to the inside of the case main body from the cutting opening surface can be suppressed compared to the conventional method. As a result, short-circuiting between positive and negative electrodes can be suppressed and the risk of the ignition can be suppressed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, some preferred embodiments of a technique disclosed herein will be described with reference to the drawings. Meanwhile, matters other than those particularly mentioned in the present specification and necessary for implementing the present disclosure (for example, general configurations and manufacturing processes of a battery which do not characterize the present disclosure) can be ascertained as a design matter of one skilled in the art based on the conventional art in the relevant field. The present disclosure can be implemented on the basis of the disclosure of the present specification and common technical knowledge in the relevant field.

Note that in the present specification, “battery” is a term that refers to a general power storage device that is capable of extracting electric energy, and refers to a concept encompassing a primary battery and a secondary battery. In addition, in the present specification, the term “secondary battery” refers to a general power storage device that is capable of being charged and discharged repeatedly, and refers to a concept encompassing a so-called storage battery (chemical battery) such as a lithium ion secondary battery, and a physical battery such as a lithium ion capacitor.

FIG.1is a perspective view of a battery100to be subjected to a process disclosed herein.FIG.2is a schematic longitudinal cross-sectional view taken along line II-II inFIG.1. In the following description, reference signs L, R, F, Rr, U, and D in the drawings respectively denote left, right, front, rear, up, and down. In addition, reference signs X and Y in the drawings respectively denote a short side direction and a long side direction of the battery100, and a reference sign Z denotes a vertical direction. Note that in the drawings below, the members and parts with the same operation are denoted by the same reference signs and the overlapping description may be omitted or simplified.

As shown inFIG.2, the battery100includes an exterior body10, a blind rivet16, an electrode body20, a positive electrode terminal30, a negative electrode terminal40, a positive electrode current collecting unit50, a negative electrode current collecting unit60, a positive electrode internal insulating member70, and a negative electrode internal insulating member80. Although not illustrated, the battery100in this case further includes an electrolyte solution. In this case, the battery100is a nonaqueous electrolyte secondary battery. Note that the structure of the battery100may be similar to that in the related art and is not particularly limited. In addition, the blind rivet16, the positive electrode internal insulating member70, and the negative electrode internal insulating member80are not always necessary, and can be omitted partially or entirely in another embodiment.

The exterior body10is a housing that accommodates the electrode body20. As shown inFIG.1, the external shape of the exterior body10is a flat and bottomed cuboid shape (rectangular shape) in this case. A conventionally used material can be used for the exterior body10, without particular limitations. The exterior body10is preferably made of metal, and is formed of a metal material with small weight and high thermal conductivity, such as aluminum, an aluminum alloy, iron, or an iron alloy. In this case, the exterior body10is made of aluminum.

As shown inFIG.2, the exterior body10includes a case main body12having an opening12h, and a lid body (sealing plate)14that covers the opening12h. The exterior body10is unified in a manner that the lid body14is joined (for example, joined by welding) to a periphery of the opening12hof the case main body12. Joining with the lid body14can be performed by welding such as laser welding. The opening12hof the case main body12is hermetically covered (sealed).

As shown inFIG.1, the case main body12includes a bottom wall12a, a pair of long side walls12bextending from the bottom wall12aand facing each other, a pair of short side walls12cextending from the bottom wall12aand facing each other, and the opening12hfacing the bottom wall12a(seeFIG.2). The short side wall12cis smaller in area than the long side wall12b. The bottom wall12aand the opening12hare substantially rectangular in shape. Note that in the present specification, “substantially rectangular shape” is a term encompassing, in addition to a perfect rectangular shape (rectangle), for example, a shape whose corner connecting a long side and a short side of the rectangular shape is rounded, a shape whose corner includes a notch, and the like. The long side wall12band the short side wall12care examples of a side wall extending from the bottom wall12ato the opening12h.

The lid body14is a plate-shaped member that seals the opening12hof the case main body12. As shown inFIG.2, the lid body14is attached to the case main body12so as to cover the opening12h. The lid body14is substantially rectangular in shape in a plan view. The lid body14is fitted to the opening12hand faces the bottom wall12aof the case main body12. The lid body14is provided with a gas discharge valve17, two terminal extraction holes18and19, and a liquid injection hole15.

The gas discharge valve17is configured to fracture when pressure inside the exterior body10reaches a predetermined value or more and discharge a gas in the exterior body10to the outside. The terminal extraction holes18and19are formed in both end parts of the lid body14in the long side direction Y. The terminal extraction holes18and19penetrate the lid body14in the vertical direction Z. The liquid injection hole15is a hole for injecting the electrolyte solution after the lid body14is assembled to the case main body12. As shown inFIG.2, the liquid injection hole15penetrates the lid body14in the vertical direction Z. The liquid injection hole15is sealed by the blind rivet16. The liquid injection hole15is one example of a penetration hole provided to the lid body14.

The blind rivet16is a member that covers the liquid injection hole15of the lid body14. The blind rivet16is typically made of metal. The structure of the blind rivet16may be similar to the conventional structure thereof. The blind rivet16in this case includes an inserted part, a flange part, and an enlarged diameter part. The inserted part has a smaller outer diameter than the liquid injection hole15, and is inserted into the liquid injection hole15. The flange part extends upward from an upper end of the inserted part, and protrudes from the liquid injection hole15to the outside of the exterior body10. The enlarged diameter part extends downward (toward an opposite side of the inserted part) from a lower end of the inserted part, and has a larger outer diameter than the liquid injection hole15. The blind rivet16is fixed by caulking to the lid body14by the flange part and the enlarged diameter part. In the structure of the battery100including the blind rivet16, a clearance is secured between the lid body14and the electrode body20.

The electrode body20includes a positive electrode and a negative electrode. In this case, the electrode body20is a wound electrode body in which the positive electrode with a band shape and the negative electrode with a band shape are stacked via a separator with a band shape and wound using a winding axis as a center in the long side direction. The external shape of the electrode body20is a flat shape. However, the electrode body20may be a laminated electrode body in which a positive electrode with a square shape and a negative electrode with a square shape are laminated on each other in an insulated state. In this case, the wound electrode body20is accommodated inside the exterior body10so that the winding axis is substantially parallel to the long side direction Y. However, the wound electrode body20may be accommodated inside the exterior body10so that the winding axis is substantially parallel to the vertical direction Z. However, the number of electrode bodies20accommodated in the exterior body10may be one, or two or more (plural).

The positive electrode includes a positive electrode current collector and a positive electrode mixture layer fixed onto the positive electrode current collector. The positive electrode current collector is formed of a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. The positive electrode current collector in this case is made of aluminum. The positive electrode mixture layer typically contains a positive electrode active material (for example, a lithium transition metal complex oxide) capable of reversibly storing and releasing charge carriers, and a binder (for example, polyvinylidene fluoride (PVdF)).

The negative electrode includes a negative electrode current collector and a negative electrode mixture layer fixed onto the negative electrode current collector. The negative electrode current collector is formed of a conductive metal such as copper, a copper alloy, nickel, or stainless steel. The negative electrode current collector in this case is made of copper. The negative electrode mixture layer typically contains a negative electrode active material (for example, carbon material such as graphite) capable of reversibly storing and releasing charge carriers, and a binder (for example, styrene butadiene rubber (SBR) or carboxymethyl cellulose (CMC)).

At one end part (left end part inFIG.2) of the electrode body20in the long side direction Y, a part of the positive electrode current collector (positive electrode tab23) where the positive electrode mixture layer is not formed is exposed. To the positive electrode tab23, a lower end part of the positive electrode current collecting unit50is connected. In addition, at the other end part (right end part inFIG.2) of the electrode body20in the long side direction Y, a part of the negative electrode current collector (negative electrode tab25) where the negative electrode mixture layer is not formed is exposed. To the negative electrode tab25, a lower end part of the negative electrode current collecting unit60is connected.

In this case, the electrolyte solution is a nonaqueous liquid electrolyte (nonaqueous electrolyte solution) containing a nonaqueous solvent and a supporting salt. For example, the nonaqueous solvent includes carbonates such as ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC). The supporting salt is, for example, a fluorine-containing lithium salt such as LiPF6. However, the electrolyte solution may have a solid form (a solid electrolyte) to be integrated with the electrode body20.

As shown inFIG.1andFIG.2, the positive electrode terminal30is disposed at one end part of the lid body14in the long side direction Y (left end part inFIG.1andFIG.2). As shown inFIG.2, the positive electrode terminal30is electrically connected to the positive electrode of the electrode body20through the positive electrode current collecting unit50inside the exterior body10. The positive electrode terminal30is inserted to the terminal extraction hole18and extends to the outside from the inside of the lid body14. The positive electrode terminal30is formed of metal such as aluminum, an aluminum alloy, nickel, or stainless steel. In this case, the positive electrode terminal30is formed of aluminum. The positive electrode terminal30is insulated from the lid body14by the positive electrode internal insulating member70and a gasket90.

A positive electrode external conductive member32with a plate shape is fixed on the positive electrode terminal30. The positive electrode external conductive member32is a member that is connected to another battery or an external device via a bus bar or the like. The positive electrode external conductive member32is attached to the lid body14in a state of being insulated from the lid body14by an external insulating member92. The positive electrode external conductive member32is formed of metal such as aluminum, an aluminum alloy, nickel, or stainless steel. In this case, the positive electrode external conductive member32is formed of aluminum.

As shown inFIG.1andFIG.2, the negative electrode terminal40is disposed at the other end part of the lid body14in the long side direction Y (right end part inFIG.1andFIG.2). As shown inFIG.2, the negative electrode terminal40is electrically connected to the negative electrode of the electrode body20through the negative electrode current collecting unit60inside the exterior body10. The negative electrode terminal40is inserted to the terminal extraction hole19and extends to the outside from the inside of the lid body14. The negative electrode terminal40is formed of metal such as copper, a copper alloy, nickel, or stainless steel. In this case, the negative electrode terminal40is formed of copper. The negative electrode terminal40is insulated from the lid body14by the negative electrode internal insulating member80and the gasket90.

A negative electrode external conductive member42with a plate shape is fixed on the negative electrode terminal40. The negative electrode external conductive member42is a member that is connected to another battery or an external device via the bus bar or the like. The negative electrode external conductive member42is attached to the lid body14in a state of being insulated from the lid body14by the external insulating member92. The negative electrode external conductive member42is formed of metal such as copper, a copper alloy, nickel, or stainless steel. In this case, the negative electrode external conductive member42is formed of copper.

The positive electrode current collecting unit50constitutes a conductive path that electrically connects the positive electrode tab23and the positive electrode terminal30. The positive electrode current collecting unit50may be formed of the same metal species as the positive electrode current collector, for example, a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. In this case, the positive electrode current collecting unit50has a substantially L-like shape. The positive electrode current collecting unit50includes a positive electrode first current collecting unit and a positive electrode second current collecting unit. The positive electrode first current collecting unit extends along an inner surface of the lid body14and is connected to the positive electrode terminal30. The positive electrode second current collecting unit extends along the short side wall12cof the case main body12and is connected to the positive electrode tab23.

The negative electrode current collecting unit60constitutes a conductive path that electrically connects the negative electrode tab25and the negative electrode terminal40. The negative electrode current collecting unit60may be formed of the same metal species as the negative electrode current collector, for example, a conductive metal such as copper, a copper alloy, nickel, or stainless steel. In this case, the negative electrode current collecting unit60has a substantially L-like shape. The negative electrode current collecting unit60includes a negative electrode first current collecting unit and a negative electrode second current collecting unit. The negative electrode first current collecting unit extends along the inner surface of the lid body14and is connected to the negative electrode terminal40. The negative electrode second current collecting unit extends along the short side wall12cof the case main body12and is connected to the negative electrode tab25.

The positive electrode internal insulating member70is provided between the inner surface of the lid body14and the electrode body20. The positive electrode internal insulating member70is a member that insulates between the lid body14and the positive electrode current collecting unit50(in detail, the positive electrode first current collecting unit) inside the exterior body10. For example, the positive electrode internal insulating member70is made of a resin material that has resistance against the electrolyte solution to be used and an electrical insulating property and that is capable of elastic deformation. The positive electrode internal insulating member70is favorably made of a polyolefin-based resin such as polypropylene (PP), a fluorinated resin such as tetrafluoroethylene-perfluoroalkoxy ethylene copolymer (PFA), or polyphenylene sulfide (PPS), for example. The positive electrode internal insulating member70is one example of an insulating member.

As shown inFIG.2, the positive electrode internal insulating member70in this case includes a base part70aand a protrusion part70b. In this case, the base part70aand the protrusion part70bare integrally molded. The base part70ais disposed between the lid body14and the positive electrode first current collecting unit and extends along the inner surface of the lid body14. The protrusion part70bprotrudes to a side of the electrode body20compared to the base part70a. As shown inFIG.2, in the long side direction Y, the protrusion part70bis provided on a side of the center of the lid body14compared to the base part70a. In the structure of the battery100including the positive electrode internal insulating member70with the protrusion part70b, the clearance is secured between the lid body14and the electrode body20.

As shown inFIG.2, the negative electrode internal insulating member80is disposed symmetrical to the positive electrode internal insulating member70with respect to the long side direction Y of the electrode body20. A specific structure of the negative electrode internal insulating member80may be similar to that of the positive electrode internal insulating member70. The negative electrode internal insulating member80is a member that insulates between the lid body14and the negative electrode current collecting unit60(in detail, the negative electrode first current collecting unit) inside the exterior body10. In this case, similarly to the positive electrode internal insulating member70, the negative electrode internal insulating member80includes a base part80adisposed between the lid body14and the negative electrode first current collecting unit, and a protrusion part80bthat protrudes to a side of the electrode body20compared to the base part80a.

<Processing Method for Battery100>

A processing method in the present embodiment is a method for opening the exterior body10of the battery100that is collected from a market. Note that the collected battery100may be in an unused state or a used state. The collected battery100may be in a state where the battery cannot be used due to overcharge, overdischarge, or the like and discharge is impossible.

The processing method in the present embodiment includes a voltage checking step (step S1), a discharge processing step (step S2), a hole working step (step S3), a deactivation processing step (step S4), a drainage step (step S5), and a cutting step (step S6) in this order. In addition, another step can be included at any stage.FIG.3is a schematic view of the battery100in the hole working step (step S3),FIG.4is a schematic view of the battery100in the drainage step (step S5), andFIGS.5A to5Care schematic views of the battery100in the cutting step (step S6).

In the voltage checking step (step S1), the collected battery100is connected to a charging and discharging device and the voltage (voltage at collection) is checked. Note that in the present step, the battery100(in detail, the exterior body10) is typically in a normal posture in which the lid body14is positioned directly above in the vertical direction Z, and the long side walls12band short side walls12cextend along the vertical direction Z. However, the battery100may be, for example, in a fallen posture to be described below other than the normal posture.

In many case, the collected battery100has a voltage. If the collected battery100has the voltage, a discharge process is preferably performed before the cutting step (step S6). Thus, the process advances to step S2. However, when the collected battery100does not have the voltage, the discharge is impossible, or the like, the discharge process can be omitted. Thus, step S2may be omitted and the process may advance to step S3, or steps S2to S5may be omitted and the process may advance to step S6.

In the discharge processing step (step S2), the battery100is compulsively discharged to reduce the voltage of the battery100. Thus, the safety in the operations in the following steps can be increased. In detail, the risks of the occurrence of a large quantity of gas in the deactivation processing step (step S4) and the ignition due to short-circuiting between the positive and negative electrodes in the cutting step (step S6) can be reduced. Note that in the present step, the battery100(in detail, the exterior body10) is typically in the normal posture. However, the battery100may be, for example, in the fallen posture to be described below other than the normal posture.

The discharge process can be performed in a manner similar to the conventional one. In many cases, the collected batteries100vary in state of charge (SOC). Thus, a discharge condition in the present step such as a discharge rate and an attainment voltage at constant current discharge (CC discharge) and a holding voltage and a holding time at constant voltage discharge (CV discharge) is preferably adjusted as appropriate depending on the voltage of the battery100at the collection. From the viewpoint of increasing the safety in the operations in the following steps, it is preferable that a residual voltage be made as low as possible. Therefore, the discharge process is preferably performed until the residual voltage of the battery100becomes about 0.5 V or less, for example, substantially 0 V. Then, the process advances to step S3.

As shown inFIG.3, in the hole working step (step S3), a hole h through which a liquid flows into the exterior body10is made at the exterior body10. The hole h has the size such that the liquid typically can flow into the exterior body10but the electrode body20cannot be extracted. The number of holes h may be one, or two or more (plural). However, if the collected battery100already has a hole (for example, the gas discharge valve17has been fractured) and the like, the present step may be omitted and the process may advance to step S4.

The hole h can be made at the exterior body10by a tool such as a drill or a gimlet. An atmosphere when the hole h is made is preferably an inert gas atmosphere. Note that in the present step, the battery100(in detail, the exterior body10) is typically in the normal posture. However, the battery100may be, for example, in the fallen posture to be described below other than the normal posture.

Although not particularly limited, when the battery100includes the liquid electrolyte (nonaqueous electrolyte solution), it is preferable that the hole h be made at a part that is positioned above the exterior body10in the vertical direction Z. For example, if the battery100(in detail, the exterior body10) is in the normal posture, it is preferable that the hole h be made at the lid body14. Thus, it is possible to prevent the nonaqueous electrolyte solution from spilling from the exterior body10when the hole h is made.

It is preferable that the hole h be made at a part apart from the positive electrode terminal30and the negative electrode terminal40, for example, a position of the gas discharge valve17provided to the lid body14as shown inFIG.3. As described above, the gas discharge valve17is configured to fracture when the pressure inside the exterior body10reaches the predetermined value or more. Thus, the gas discharge valve17is the weakest part of the exterior body10where the hole h can be made easily. Therefore, the hole h can be made with a relatively small power. As shown inFIG.3, the hole h may be larger than the gas discharge valve17, for example. The part where the hole h is made may be another part of the exterior body10, for example, a part of the lid body14other than the gas discharge valve17, and the bottom wall12a, the long side wall12b, and the short side wall12cof the case main body12. Then, the process advances to step S4.

In the deactivation processing step (step S4), a conductive liquid (deactivation processing liquid) such as a saline solution is fed into the exterior body10from the hole h of the exterior body10, so that the battery100is deactivated. As the method of feeding the deactivation processing liquid into the exterior body10, the deactivation processing liquid may be injected into the exterior body10from the hole h or the exterior body10itself may be immersed in the deactivation processing liquid, for example. Note that in the present step, the battery100(in detail, the exterior body10) is typically in the normal posture. However, when the exterior body10itself is immersed in the deactivation processing liquid, for example, the battery100may be, for example, in the fallen posture to be described below other than the normal posture.

The deactivation process (typically, saline solution process) may be performed in a manner similar to the conventional one. A deactivation processing condition such as a processing time, the concentration of a processing agent (salt (sodium chloride) or the like), or the electric conductivity of the deactivation processing liquid may be adjusted as appropriate depending on the residual voltage of the battery100. Thus, the battery100can be completely discharged and deactivated. Then, the process advances to step S5.

In the drainage step (step S5), the deactivation processing liquid that has flowed into the exterior body10in the deactivation processing step (step S4) is drained. In the present embodiment, as shown inFIG.4, for example, the exterior body10is set to an inversion posture, that is, the battery100(in detail, the exterior body10) is inverted so that the hole h or the lid body14will face directly downward in the vertical direction Z. Thus, as shown by an arrow inFIG.4, the deactivation processing liquid is drained from the hole h quickly and the present step can be performed efficiently in a short time. However, the battery100may be, for example, in the fallen posture to be described below other than the inversion posture depending on the position of the hole h or the like. Then, the process advances to step S6.

In the cutting step (step S6), the exterior body10is cut along the opening12h. In the present embodiment at this time, the battery100(in detail, the exterior body10) is in a posture other than the normal posture. Note that in the present specification, “posture other than normal posture” is a concept encompassing, except for the posture in which the lid body14faces directly upward in the vertical direction Z, an upward inclined posture (not shown) in which the lid body14faces upward obliquely in the vertical direction Z, the fallen posture (seeFIGS.5A and5B) in which the lid body14faces in a horizontal direction, a downward inclined posture (not shown) in which the lid body14faces downward obliquely in the vertical direction Z, and the inversion posture (seeFIG.5C) in which the lid body14faces directly downward in the vertical direction Z. Thus, compared to a case where the present step is performed when the battery100is in the normal posture, mixing of a foreign substance such as cutting trash to the inside of the case main body12from a cutting opening surface CS can be suppressed relatively. In particular, the battery100(in detail, the exterior body10) is preferably in any one of the fallen posture, the downward inclined posture, and the inversion posture. Thus, the mixing of a foreign substance can be relatively suppressed at a high level compared to the case where the battery100(in detail, the exterior body10) is in the upward inclined posture.

In a preferred aspect, as shown inFIG.5A, the battery100(in detail, the exterior body10) is set to a first fallen posture in which the pair of long side walls12bare positioned above and below in the vertical direction Z and the lid body14faces in the horizontal direction. In another preferred aspect, as shown inFIG.5B, the battery100(in detail, the exterior body10) is set to a second fallen posture in which the pair of short side walls12care positioned above and below in the vertical direction Z and the lid body14faces in the horizontal direction. In this case, since the cutting opening surface CS along the opening12hfaces in the horizontal direction, a foreign substance such as cutting trash drops in the vertical direction and the mixing of a foreign substance to the inside of the case main body12from the cutting opening surface CS can be suppressed at a higher level.

In still another preferred aspect, as shown inFIG.5C, the battery100(in detail, the exterior body10) is set to the inversion posture in which the lid body14faces directly downward in the vertical direction Z. In this case, since the cutting opening surface CS along the opening12hfaces directly downward in the vertical direction Z, a foreign substance such as cutting trash drops in the vertical direction and the mixing of a foreign substance to the inside of the case main body12from the cutting opening surface CS can be suppressed at a much higher level. Note that if the inversion posture is employed in the drainage step (step S5), the process can directly advance to the present step and operation efficiency can be improved.

The operation of cutting the exterior body10can be performed using a conventionally known processing machine. In particular, a processing machine including a ceramic blade or a water jet cutting machine is preferably used. Thus, it is possible to prevent the conductive member (for example, the positive electrode current collector, the negative electrode current collector, the positive electrode current collecting unit50, or the negative electrode current collecting unit60) from electrically connecting with the lid body14, that is, the occurrence of a spark due to short-circuiting can be prevented. Therefore, the safety of the operation can be increased. Moreover, when the water jet cutting machine is used, the exterior body10can be cut without a thermal effect, and a cooling effect can be obtained, that is, the risk of the ignition can be suppressed.

Note that in the present specification, “water jet cutting machine” refers to a general cutting device that cuts the exterior body10using a thin water jet with high speed, high density, and high pressure energy, and refers to a concept encompassing water jet cutting in which cutting is performed by only a fluid such as water, and abrasive jet cutting in which cutting is performed by a fluid such as water with abrasive mixed therein. Note that the fluid used in cutting is typically water, but may be a fluid other than water. As the water jet cutting machine, a conventionally known one may be used. Examples thereof include Abrasive Jet Cutter by Sugino Machine Limited.

FIG.6is a picture of a cutting device according to an example. This cutting device is made by modifying a desktop circular saw board including a cutting blade on the market (for example, K-210 by HOZAN). In this modification, a guide is provided along the cutting blade in order to regulate a cutting position and adjust a protrusion allowance. In this example, the exterior body10with the fallen posture (seeFIGS.5A and5B) is slid along the guide and the pair of long side walls12band the pair of short side walls12care cut along a cutting line CL. In this case, the exterior body10is moved relative to the cutting device, but the cutting blade may be moved relative to the fixed exterior body10. The position of cutting the exterior body10(the position of the cutting line CL) can be adjusted by the distance between the cutting blade and the guide. Thus, the case main body12and the lid body14can be separated from each other. In many cases, the collected batteries100vary in size and structure. However, by using the cutting device including such a guide, the batteries100with various sizes and structures can be cut stably by just changing the position of the guide. Therefore, this method is efficient.

Note that the position of cutting the exterior body10(the position of the cutting line CL) is preferably a position in which the electrode body20will not be damaged. For example, in order to prevent the electrode body20from being damaged, connection parts between the electrode body20, and the positive electrode terminal30and the negative electrode terminal40(in detail, parts of the positive electrode current collecting unit50and the negative electrode current collecting unit60) are preferably cut. In a preferred aspect, as shown inFIG.7, a position corresponding to the place between an inner side surface14dof the lid body14and an upper end20tof the electrode body20is set as the cutting line CL and the exterior body10is cut. In an example, the exterior body10is preferably cut at a position 2 to 4.5 mm from an upper surface of the lid body14. However, the cutting position is not limited to this example particularly, because the cutting position may vary depending on the size, structure, and the like of the battery100.

As described above, in the structure of the battery100including the blind rivet16, the clearance exists between the inner side surface14dof the lid body14and the upper end20tof the electrode body20. Such a clearance always exists at a fixed position. Thus, by cutting the exterior body10(in detail, the case main body12) at a part of the clearance (space part), the exterior body10can be cut without the damage of the electrode body20even when the cutting blade penetrates the exterior body10. Note that whether the battery100includes the blind rivet16can be determined based on the external appearance of the battery100. Thus, without extra inspection or the like before cutting, the cutting position (the position of the cutting line CL) in which the electrode body20will not be damaged can be determined, which is convenient.

In addition, in the structure of the battery100including at least one of the positive electrode internal insulating member70with the protrusion part70band the negative electrode internal insulating member80with the protrusion part80b, the clearance exists between the inner side surface14dof the lid body14and the upper end20tof the electrode body20. Thus, by cutting the exterior body10(in detail, the case main body12) at the part of the clearance (the space part), the exterior body10can be cut without the damage of the electrode body20even when the cutting blade penetrates the exterior body10. In this case, for example, after the position of the space part is checked by X-ray inspection or the like, the cutting position (the position of the cutting line CL) in which the electrode body20will not be damaged may be determined.

The battery100is processed as described above to open the exterior body10, and thus, the case main body12and the lid body14can be separated from each other. The case main body12can be recycled as aluminum. In addition, the electrode body20is extracted from the case main body12and separated into a mixture (so-called, black mass) and a current collector, and then, a valuable metal can be collected from the electrode body20by a conventionally known method. For example, a rare metal such as lithium (Li) or a transition metal (for example, Ni, Co, and Mn) can be collected.

As described above, the following items are given as specific aspects of the art disclosed herein.Item 1: The processing method for a battery that includes the exterior body and the electrode body accommodated in the exterior body, the exterior body including: the case main body including the bottom wall, the opening that faces the bottom wall, and the side walls that extend from the bottom wall to the opening; and the lid body that seals the opening of the case main body, and the processing method including the cutting step of, when the posture in which the lid body is positioned directly above in the vertical direction and the side walls extend along the vertical direction is defined as the normal posture, cutting the exterior body in the posture other than the normal posture along the opening.Item 2: The processing method according to Item 1, in which in the cutting step, the position corresponding to the place between the electrode body and the lid body is cut.Item 3: The processing method according to Item 1 or 2, in which the lid body includes the penetration hole, and the battery further includes the blind rivet that covers the penetration hole.Item 4: The processing method according to any one of Items 1 to 3, in which the battery further includes the insulating member that is provided between the electrode body and the lid body, and the insulating member includes the base part that extends along the inner surface of the lid body and the protrusion part that protrudes to the side of the electrode body compared to the base part.Item 5: The processing method according to any one of Items 1 to 4, in which in the cutting step, the exterior body is set to any one of the fallen posture in which the lid body faces in the horizontal direction, the downward inclined posture in which the lid body faces downward obliquely in the vertical direction, and the inversion posture in which the lid body faces directly downward in the vertical direction.Item 6: The processing method according to any one of Items 1 to 4, in which in the cutting step, the exterior body is set to the inversion posture in which the lid body faces directly downward in the vertical direction.Item 7: The processing method according to any one of Items 1 to 4, in which the side walls include the pair of short side walls and the pair of long side walls, and in the cutting step, the exterior body is set to the first fallen posture in which the pair of long side walls are positioned above and below in the vertical direction and the lid body faces in the horizontal direction.Item 8: The processing method according to any one of Items 1 to 4, in which the side walls include the pair of short side walls and the pair of long side walls, and in the cutting step, the exterior body is set to the second fallen posture in which the pair of short side walls are positioned above and below in the vertical direction and the lid body faces in the horizontal direction.Item 9: The processing method according to any one of Items 1 to 8, further including the hole working step of making the hole at the exterior body and the deactivation processing step of feeding the deactivation processing liquid into the exterior body in this order, before the cutting step.Item 10: The processing method according to any one of Items 1 to 9, in which in the cutting step, the exterior body is cut by the water jet cutting machine.

Although the embodiments of the present disclosure have been described above, these embodiments are just examples. The present disclosure can be implemented in various other modes. The present disclosure can be implemented based on the contents disclosed in this specification and the technical common sense in the relevant field. The techniques described in the scope of claims include those in which the embodiments exemplified above are variously modified and changed. For example, a part of the aforementioned embodiment can be replaced by another modified aspect, and the other modified aspect can be added to the aforementioned embodiment. Additionally, the technical feature may be deleted as appropriate unless such a feature is described as an essential element.

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