Method for manufacturing an electricity storage device

Abstract

To provide a manufacturing method capable of improving easy detachability of an adhesive tape after temporary sealing.SOLUTION: There is provided a manufacturing method for a power storage device comprising an electrode body, electrolyte, a case body that has an aperture and houses the electrode body and the electrolyte, and a lid that has a liquid injection hole and closes the aperture of the case body. The manufacturing method includes: a temporary sealing step (S2) of pasting an adhesive tape on the lid so as to cover the liquid injection hole; and an opening step (S4) of peeling the adhesive tape pasted on the lid. In the temporary sealing step (S2), the adhesive tape and the lid are made to adhere closely at the periphery of the liquid injection hole and at least part of the adhesive tape is made to be in a state floated from the lid at a part apart from the liquid injection hole.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] An electricity storage device typically includes an electrode body, an electrolyte, a case body having an opening for accommodating the electrode body and the electrolyte, and a lid body having an injection hole for closing the opening of the case body (see Patent Documents 1 and 2).

[0003] For example, Patent Document 1 discloses a method for manufacturing an electricity storage device, which includes the following steps: a step of temporarily sealing the liquid inlet with a first sealing member (breathable film); a step of impregnating the electrode body with electrolyte while the liquid inlet is temporarily sealed with the first sealing member; a step of removing the first sealing member to open the liquid inlet; and a step of permanently sealing the liquid inlet with a second sealing member (sealing plug). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2022-139497 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-117657 Summary of the Invention [Problem to be solved by the invention]

[0005] According to the inventors' investigations, if the first sealing member used in temporary sealing is adhesive tape, and the adhesive tape is firmly attached to the lid, it can be difficult to peel off the adhesive tape in a later process. Furthermore, as described in Patent Document 1, adhesive residue can remain on the lid after the adhesive tape is peeled off. As a result, it can be difficult to fit the second sealing member into the injection hole during final sealing.

[0006] The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a method for producing an electricity storage device that can improve the ease of peeling of an adhesive tape after temporary sealing. [Means for solving the problem]

[0007] The present invention provides a method for manufacturing an electricity storage device including an electrode assembly, an electrolyte, a case body having an opening and accommodating the electrode assembly and the electrolyte, and a lid body having a liquid inlet and closing the opening of the case body. The manufacturing method includes a temporary sealing step of attaching an adhesive tape to the lid body so as to close the liquid inlet, and an unsealing step of peeling off the adhesive tape attached to the lid body, wherein in the temporary sealing step, the adhesive tape is attached to a peripheral portion of the liquid inlet, while at least a portion of the adhesive tape is raised from the lid body in a portion away from the liquid inlet.

[0008] After extensive research, the inventors of the present invention have newly discovered the following. Specifically, when peeling an adhesive tape from a lid, people often hook the edge of the adhesive tape with a fingernail, tweezers, or other gripping tool and turn it up. However, if the adhesive tape is tightly attached to the lid all the way to the edge, it is difficult to hook the edge of the adhesive tape with a fingernail or other gripping tool. As a result, a large external force is required at the beginning of peeling, which makes it particularly easy for adhesive material to remain (so-called adhesive residue).

[0009] Therefore, in the present invention, in the temporary sealing step, the adhesive tape at a portion away from the liquid injection hole is raised from the lid. This makes it easier to peel the adhesive tape from the raised portion of the lid as a starting point in the unsealing step. Therefore, the external force required at the start of peeling is reduced. Furthermore, after the adhesive tape is peeled, adhesive material is less likely to remain around the liquid injection hole, making it easier to fit the sealing member to the liquid injection hole. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1 is a perspective view schematically illustrating an electricity storage device according to one embodiment. [Figure 2] FIG. 2 is a perspective view schematically showing an electrode assembly. [Figure 3] FIG. 3 is a schematic diagram showing the configuration of the electrode body. [Figure 4] FIG. 4 is a flowchart of a manufacturing method according to one embodiment. [Figure 5] FIG. 5 is a side view schematically showing the main part of the tape applying device. [Figure 6] 6(A) to 6(F) are schematic diagrams illustrating the temporary sealing step. [Figure 7] FIG. 7(A) is a plan view schematically showing the lid body after the temporary sealing step, and FIG. 7(B) is a schematic longitudinal cross-sectional view taken along line IIV(B)-IIV(B) in FIG. 7(A). [Figure 8] FIG. 8 is a schematic diagram illustrating the opening process. [Figure 9] FIG. 9 is a view corresponding to FIG. 8 according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, some preferred embodiments of the technology disclosed herein will be described with reference to the drawings. Matters necessary for implementing the present invention other than those specifically mentioned in this specification (for example, the general configuration and manufacturing process of an electricity storage device that do not characterize the technology disclosed herein) can be understood as design matters for those skilled in the art based on prior art in the field. The technology disclosed herein can be implemented based on the contents disclosed in this specification and common technical knowledge in the field.

[0012] In this specification, the term "electricity storage device" refers to a device in general that can be repeatedly charged and discharged, and is a concept that encompasses not only storage batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries, but also capacitors such as lithium-ion capacitors and electric double layer capacitors. Furthermore, in this specification, the notation "A to B" indicating a numerical range not only means "A or more and B or less," but also encompasses the meanings of "greater than A" and "below B."

[0013] <Electricity storage device 100> First, an energy storage device 100 manufactured by the manufacturing method disclosed herein will be described. FIG. 1 is a perspective view of the energy storage device 100. In the following description, the symbol X indicates the "short side direction" of the energy storage device 100, the symbol Y indicates the "long side direction" perpendicular to the short side direction, and the symbol Z indicates the "height direction" perpendicular to the short side direction and the long side direction. In addition, F in the short side direction X indicates "front" and Rr indicates "rear." In the long side direction Y, L indicates "left" and R indicates "right." In the height direction Z, U indicates "up" and D indicates "down." However, these directions are merely used for the convenience of explanation and do not limit the installation form of the energy storage device 100 in any way.

[0014] The electricity storage device 100 includes a battery case 10, an electrode assembly 20 (not shown in FIG. 1, see FIGS. 2 and 3), and an electrolyte (not shown). The electricity storage device 100 here is a lithium ion secondary battery.

[0015] The battery case 10 includes a case body 12 having an opening and a lid (sealing plate) 14 that closes the opening. The lid 14 is joined to the periphery of the opening of the case body 12 to form an integrated battery case 10, which is hermetically sealed (sealed). Here, the battery case 10 has a flat, bottomed, rectangular parallelepiped (square) shape. However, in other embodiments, the battery case 10 may have a cubic or cylindrical shape, for example.

[0016] The case body 12 is a housing that houses the electrode assembly 20 and the electrolyte. The case body 12 has a rectangular bottom surface 12a, a pair of wide surfaces 12b, and a pair of narrow surfaces 12c. The pair of wide surfaces 12b rise from the two long sides of the bottom surface 12a, respectively. The pair of narrow surfaces 12c rise from the two short sides of the bottom surface 12a, respectively. The lid body 14 is a flat plate-shaped member. The lid body 14 faces the bottom surface 12a of the case body 12. The lid body 14 has an upper surface 14u. The upper surface 14u is the surface on the side away from the case body 12 and forms the outer surface of the battery case 10. In this example, the lid body 14 is substantially rectangular. In this specification, the term "approximately rectangular" refers not only to a perfect rectangular shape (rectangular shape), but also to shapes such as those in which the corners connecting the long and short sides of the rectangle are rounded, or those in which the corners have notches.

[0017] The lid 14 is provided with a liquid inlet 15, a safety valve 17, a positive electrode external terminal 30, and a negative electrode external terminal 40. The liquid inlet 15 is a through-hole for injecting electrolyte into the battery case 10 after the lid 14 is assembled to the case body 12. Here, the liquid inlet 15 is formed in a circular shape in a plan view. The liquid inlet 15 is sealed with a sealing member 16. The sealing member 16 is preferably a sealing plug having a portion that can be inserted into the sealing member 16. The safety valve 17 is a thin-walled portion that is configured to rupture when the pressure inside the battery case 10 reaches or exceeds a predetermined value, thereby discharging gas inside the battery case 10 to the outside. The positive electrode external terminal 30 and the negative electrode external terminal 40 are electrically connected to the electrode body housed in the battery case 10.

[0018] Although not particularly limited, the battery case 10 is made of, for example, a metal. Examples of the metal material constituting the battery case 10 include aluminum, aluminum alloys, iron, and iron alloys. Alternatively, the battery case 10 may be made of a heat-resistant resin material such as polyimide resin.

[0019] The electrode body 20 (see FIGS. 2 and 3) is housed inside the battery case 10 (more specifically, inside the case body 12). The number of electrode bodies 20 arranged inside one battery case 10 is not particularly limited, and may be one or two or more (plural).

[0020] Fig. 2 is a perspective view of the electrode body 20. Fig. 3 is a schematic diagram showing the configuration of the electrode body 20. As shown in Figs. 2 and 3, a positive electrode internal terminal 50 and a negative electrode internal terminal 60 are attached to the electrode body 20. The positive electrode internal terminal 50 is connected to the positive electrode external terminal 30 (see Fig. 1). The negative electrode internal terminal 60 is connected to the negative electrode external terminal 40 (see Fig. 1).

[0021] As shown in FIG. 3, the electrode assembly 20 has a positive electrode 22 and a negative electrode 24. Here, the electrode assembly 20 is a flat wound electrode assembly in which a strip-shaped positive electrode 22 and a strip-shaped negative electrode 24 are stacked with a strip-shaped separator 26 interposed therebetween and wound around a winding axis WL. As shown in FIG. 2, the electrode assembly 20 has a pair of flat portions 20a with flat outer surfaces and a pair of curved portions 20b with curved outer surfaces. However, in other embodiments, the electrode assembly 20 may be a laminated electrode assembly in which a square-shaped (typically rectangular) positive electrode and a square-shaped (typically rectangular) negative electrode are stacked in an insulated state.

[0022] Although detailed illustration is omitted, the electrode body 20 is disposed inside the case body 12 with the winding axis WL oriented parallel to the long side direction Y. When housed in the battery case 10 of FIG. 1, the pair of flat portions 20a of the electrode body 20 face the wide surfaces 12b of the battery case 10, and the pair of curved portions 20b face the narrow surfaces 12c.

[0023] The positive electrode 22 has a strip-shaped positive electrode current collector foil 22c (e.g., aluminum foil) and a positive electrode active material layer 22a fixed to at least one surface of the positive electrode current collector foil 22c. Although not particularly limited, a positive electrode protective layer 22p may be provided on one side edge portion in the long side direction Y of the positive electrode 22, as necessary. Note that the materials constituting the positive electrode active material layer 22a and the positive electrode protective layer 22p can be any materials used in this type of electricity storage device (in this embodiment, a lithium ion secondary battery) without particular limitation, and detailed description thereof will be omitted as they do not characterize the technology disclosed herein.

[0024] A plurality of positive electrode tabs 22t are provided at one end of the positive electrode current collector foil 22c in the long side direction Y (the left end in FIG. 3). The plurality of positive electrode tabs 22t each protrude toward one side in the long side direction Y (the left side in FIG. 3). The plurality of positive electrode tabs 22t are provided at intervals (intermittently) along the longitudinal direction of the positive electrode 22. The positive electrode tabs 22t are part of the positive electrode current collector foil 22c, and are portions of the positive electrode current collector foil 22c where the positive electrode active material layer 22a and the positive electrode protective layer 22p are not formed (exposed current collector foil portions). The plurality of positive electrode tabs 22t are stacked at one end of the positive electrode current collector foil 22c in the long side direction Y (the left end in FIG. 3) to form a positive electrode tab group 23. A positive electrode internal terminal 50 is joined to the positive electrode tab group 23 (see FIG. 2).

[0025] The negative electrode 24 has a strip-shaped negative electrode current collector foil 24c (e.g., copper foil) and a negative electrode active material layer 24a fixed to at least one surface of the negative electrode current collector foil 24c. Note that the material constituting the negative electrode active material layer 24a can be any material used in this type of electricity storage device (in this embodiment, a lithium ion secondary battery) without any particular limitation, and is not a defining feature of the technology disclosed herein, so a detailed description thereof will be omitted.

[0026] A plurality of negative electrode tabs 24t are provided at one end of the negative electrode current collector foil 24c in the long side direction Y (the right end in FIG. 3). The plurality of negative electrode tabs 24t protrude toward one side in the long side direction Y (the right side in FIG. 3). The plurality of negative electrode tabs 24t are provided at intervals (intermittently) along the longitudinal direction of the negative electrode 24. In this example, the negative electrode tabs 24t are part of the negative electrode current collector foil 24c, and are portions of the negative electrode current collector foil 24c where the negative electrode active material layer 24a is not formed (exposed current collector foil portions). The plurality of negative electrode tabs 24t are stacked at one end of the negative electrode current collector foil 24c in the long side direction Y (the right end in FIG. 3) to form a negative electrode tab group 25. A negative electrode internal terminal 60 is joined to the negative electrode tab group 25 (see FIG. 2).

[0027] The electrolyte solution is typically a non-aqueous electrolyte solution containing a non-aqueous solvent and a supporting salt. As the non-aqueous solvent and supporting salt, various solvents used in electrolyte solutions for this type of power storage device (here, lithium ion secondary battery) can be used without particular limitation. Examples of the non-aqueous solvent include carbonates such as ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC). Examples of the supporting salt include lithium salts such as LiPF6. The electrolyte solution may contain conventionally known additives such as a film-forming agent, a thickener, and a dispersant, as necessary.

[0028] <Method of manufacturing the electricity storage device 100> FIG. 4 is a flowchart of a manufacturing method according to one embodiment. The manufacturing method shown in FIG. 4 includes the following steps, in this order: an electrode assembly housing step (step S1); a temporary sealing step (step S2); a case joining step (step S3); an opening step (step S4); a leak inspection step (step S5); a liquid injection step (step S6); and a final sealing step (step S7). However, this is merely an example of the technology disclosed herein. The temporary sealing step (step S2) and the opening step (step S4) can also be performed at other times. The order of the temporary sealing step (step S2) and the electrode assembly housing step (step S1) can also be reversed. The inspection step (step S5) is optional and can be omitted. Other steps may also be included at any stage.

[0029] The electrode assembly accommodation step (step S1) is a step of preparing the electrode assembly 20 and accommodating it in the battery case 10. In a preferred embodiment, this step includes an electrode fabrication step (step S11), an electrode assembly fabrication step (step S12), and an accommodation step (step S13). Furthermore, other steps may be included at any stage.

[0030] First, in the electrode preparation step (step S11), the positive electrode 22 and the negative electrode 24 are each prepared by a conventionally known method. The positive electrode 22 can be prepared, for example, by mixing a positive electrode active material, a conductive material, a binder, and a dispersion solvent to prepare a positive electrode composite slurry, applying the prepared positive electrode composite slurry to the positive electrode current collector foil 22c by a conventionally known method, drying, and appropriately pressing. The negative electrode 24 can be prepared, for example, by mixing a negative electrode active material, a binder, a dispersant, and a dispersion solvent to prepare a negative electrode composite slurry, applying the prepared negative electrode composite slurry to the negative electrode current collector foil 24c by a conventionally known method, drying, and appropriately pressing. Note that, although electrodes (positive electrode 22 and / or negative electrode 24) are prepared in this embodiment, in other embodiments, the electrodes may be commercially purchased and prepared.

[0031] Next, in the electrode assembly fabrication step (step S12), the positive electrode 22 and negative electrode 24 fabricated above are opposed to each other with a separator 26 interposed therebetween to fabricate the electrode assembly 20. When fabricating a flat wound electrode assembly, for example, first, a strip-shaped positive electrode 22 and a strip-shaped negative electrode 24 are stacked with a strip-shaped separator 26 interposed therebetween and wound into a cylindrical shape around a winding axis WL (winding step). Next, the cylindrically wound electrode assembly (cylindrical body) is press-molded into a flat shape (pressing step). Next, a positive electrode internal terminal 50 is attached to the positive electrode tab group 23 of the electrode assembly 20, and a negative electrode internal terminal 60 is attached to the negative electrode tab group 25. Next, a positive electrode external terminal 30 and a negative electrode external terminal 40 are attached to the lid 14. Then, internal terminals of the same polarity (positive electrode internal terminal 50 and negative electrode internal terminal 60) are joined to these external terminals (positive electrode external terminal 30 and negative electrode external terminal 40) by a conventionally known method (current collecting joining step). In this way, the electrode body 20 and the lid body 14 are integrated.

[0032] Next, in the accommodation step (step S13), the lid 14 integrated with the electrode assembly 20 is fitted into the opening of the case body 12. As a result, the electrode assembly 20 is accommodated inside the case body 12.

[0033] The temporary sealing step (step S2) is a step of attaching an adhesive tape 90 (see FIG. 5) to the lid 14 so as to close the liquid inlet 15 of the lid 14. The adhesive tape 90 is wider than the liquid inlet 15. The adhesive tape 90 is typically wound in a roll. Although not particularly limited, the average thickness of the adhesive tape 90 is approximately 1000 μm or less, typically 500 μm or less, for example 250 μm or less. Here, the adhesive tape 90 prevents spatter from entering the inside of the case body 12 through the liquid inlet 15 when spatter is generated in the subsequent case joining step (step S3).

[0034] The adhesive tape 90 typically has a base layer and an adhesive layer provided on the surface of the base layer facing the lid 14 and adhesive to the lid 14. Although not particularly limited, the base layer is preferably made of a resin material such as polyimide resin (e.g., Kapton (trademark)), fluororesin, polyethylene terephthalate (PET), or a glass material such as glass cloth. Of these, resin materials are preferred, with polyimide resin and fluororesin being particularly preferred because of their high heat resistance to sputtering (they are less likely to burn).

[0035] 5 is a side view schematically showing the main parts of a tape application device 200 used in this step. The tape application device 200 is disposed above the lid body 14 and is configured to apply an adhesive tape 90 to the periphery of the liquid injection hole 15 of the lid body 14. Below, an embodiment in which the tape application device 200 is used will be described with reference to the drawings as appropriate. However, in other embodiments, the adhesive tape 90 can also be applied to the lid body 14 by hand (manually) without using the tape application device 200.

[0036] The tape application device 200 includes an application unit 290. The application unit 290 is supported directly or indirectly by a support member (not shown). When the application unit 290 is on standby, i.e., when not performing a tape application operation, it is located at a predetermined home position (not shown). The application unit 290 includes a tape supply section 210, a tape application section 220, and a tape cutting section 230. The application unit 290 is configured to be movable from the home position to a lower application position by a vertical movement mechanism (not shown). The application unit 290 is configured to be movable in the long side direction Y by a long side direction movement mechanism (not shown). The long side direction Y is an example of a "first direction along the surface of the lid body."

[0037] The configurations of the vertical movement mechanism and the long side movement mechanism may be the same as conventional ones. The vertical movement mechanism is, for example, a lifting cylinder. The vertical movement mechanism is electrically connected to a control unit (not shown). The joining unit 290, i.e., the tape supply unit 210, the tape joining unit 220, and the tape cutting unit 230, are moved together toward the side (joining position) closer to the lid body 14 by driving the lifting cylinder.

[0038] The long-side direction movement mechanism includes, for example, a guide rail extending in the long-side direction and a drive motor. The joining unit 290 is slidably engaged with the guide rail. The drive motor is connected to the joining unit 290 via, for example, a ball screw or the like. The drive motor is electrically connected to a control unit (not shown). The joining unit 290, i.e., the tape supply unit 210, the tape joining unit 220, and the tape cutting unit 230, move integrally on the guide rail in the long-side direction Y as the drive motor rotates. Note that in FIG. 5, the right side is the front side in the traveling direction of the joining unit 290, and the left side is the rear side in the traveling direction of the joining unit 290.

[0039] The tape supply unit 210 is configured to supply the adhesive tape 90 to the joining roller 221 (described later). The tape supply unit 210 is disposed to the right of the joining roller 221 (front side in the traveling direction). The tape supply unit 210 includes a supply reel (not shown) around which the adhesive tape 90 is wound, a guide roller 211, a roller support member 212 that supports the guide roller 211, a tape supply path 213, a tape chuck 214, and a supply unit movement mechanism (not shown). The supply unit movement mechanism moves the tape supply unit 210 independently (in other words, separately from the tape joining unit 220 and the tape cutting unit 230) upward from the joining position. The configuration of the supply unit movement mechanism is not particularly limited, but may be, for example, a drive motor. The supply unit movement mechanism drives the drive motor to move the roller support member 212 in the vertical direction. This causes the guide roller 211 to move in the vertical direction.

[0040] The guide roller 211 is a member that pulls out the adhesive tape 90 from the supply reel and guides it to the vicinity of the joining roller 221. The guide roller 211 has a long cylindrical shape. The guide roller 211 is arranged so that its cylindrical axis is along the short side direction X. The guide roller 211 is rotatably supported by the roller support member 212 around an axis extending in the short side direction X. The guide roller 211 may be configured to rotate, for example, by a connected motor or the like. The length of the guide roller 211 in the short side direction X is typically longer than the width of the adhesive tape 90. The length of the guide roller 211 in the short side direction X may be shorter than the length of the lid body 14.

[0041] The tape supply path 213 constitutes a travel path for the adhesive tape 90, which passes the adhesive tape 90 pulled out from the supply reel and is laid over the guide roller 211. In this example, the tape supply path 213 is a guide rail that extends along the lower surface of the roller support member 212. As shown in FIG. 5, at the attachment position, the angle θ formed between the tape supply path 213 and the upper surface 14u of the lid 14 is preferably 20 to 50°. This makes it easier to attach the adhesive tape 90 to the upper surface 14u of the lid 14.

[0042] The tape supply path 213 is provided with a suction mechanism. Here, a plurality of suction holes for suctioning the adhesive tape 90 are provided on the guide rail. The plurality of suction holes are connected to a suction pump (not shown). The suction pump is electrically connected to a control unit (not shown). When the suction pump is driven, the space between the tape supply path 213 and the adhesive tape 90 is depressurized through the plurality of suction holes. As a result, the adhesive tape 90 is fixed by suction to the tape supply path 213.

[0043] A tape chuck 214 is provided midway along the tape supply path 213. The tape chuck 214 is normally closed and supports from below the adhesive tape 90 that is fixed by suction to the tape supply path 213. The tape chuck 214 is configured to move downward and automatically open during the joining operation by an appropriate mechanism (not shown).

[0044] The tape application unit 220 is configured to apply the adhesive tape 90 to the upper surface 14u of the lid body 14. The tape application unit 220 includes an application roller 221, a roller support member 222 that supports the application roller 221, and an application unit movement mechanism (not shown). The application unit movement mechanism moves the application roller 221 upward from the application position. The configuration of the supply unit movement mechanism is not particularly limited, but is, for example, a drive motor. The application unit movement mechanism drives the drive motor to move the roller support member 222 in the vertical direction. This causes the application roller 221 to move in the vertical direction.

[0045] The applying roller 221 is a member that presses the adhesive tape 90 against the upper surface 14u of the lid body 14. The applying roller 221 is arranged alongside the tape supply unit 210 (more specifically, the guide roller 211) in the long side direction Y. The applying roller 221 is arranged to the left of the tape supply unit 210 (rear in the traveling direction). The applying roller 221 has a long cylindrical shape. The applying roller 221 is arranged so that its cylindrical axis is along the short side direction X. The applying roller 221 is supported by a roller support member 222 so as to be rotatable about an axis extending in the short side direction X. The applying roller 221 may be configured to rotate, for example, by a connected motor or the like. The length of the applying roller 221 in the short side direction X is typically longer than the width of the adhesive tape 90. The length of the applying roller 221 in the short side direction X may be shorter than the length of the lid body 14. The joining roller 221 may be configured to press the upper surface 14u of the lid 14 more strongly than the guide roller 211 by means of a biasing mechanism such as a spring.

[0046] The tape cutting unit 230 includes a cutter 231, a cutter support member 232 that supports the cutter 231, a cutter moving mechanism (not shown), and a cutting mechanism (not shown). The cutter moving mechanism moves the cutter 231 upward from the application position. The configuration of the cutter moving mechanism is not particularly limited, but may be a drive motor, for example. The cutter moving mechanism moves the cutter support member 232 in the up and down direction by driving the drive motor. The cutting mechanism moves the cutter 231 from the application position to a cutting position diagonally downward. The configuration of the cutting mechanism is not particularly limited, but may be a piston cylinder, for example. The cutting mechanism is configured to move reciprocally diagonally downward by driving the piston cylinder, thereby cutting the adhesive tape 90.

[0047] The cutter 231 is a member that cuts the adhesive tape 90. The cutter 231 extends diagonally downward (toward the upper surface 14u of the lid 14). At the joining position, the lower end 231d of the cutter 231 is disposed at approximately the same height as the upper end of the guide roller 211 and the upper end of the joining roller 221. The lower end 231d of the cutter 231 is disposed between the guide roller 211 and the joining roller 221 in the long side direction Y.

[0048] 6A to 6F are schematic diagrams illustrating this step. The lid 14 is not shown in FIG. 6. For the reference numerals of the various components, see FIG. 5. In this step, as shown in FIG. 5, the joining unit 290 (i.e., the tape supply unit 210, the tape joining unit 220, and the tape cutting unit 230) is first moved from its home position to its joining position by the vertical movement mechanism. When the joining unit 290 is moved from its home position to its joining position, the lower ends of the guide roller 211 and the joining roller 221 come into contact with the upper surface 14u of the lid 14. However, if the guide roller 211 is configured to rotate by a motor or the like, the guide roller 211 does not need to come into contact with the upper surface 14u of the lid 14. At this time, the tape chuck 214 of the tape supply unit 210 is closed, and the suction pump is driven. Therefore, the adhesive tape 90 is fixed to the tape supply path 213.

[0049] Next, as shown in FIG. 6(A), the tape chuck 214 of the tape supply unit 210 is released, and the suction pump (not shown) is stopped. In this state, the adhering operation is performed. More specifically, as shown by the arrow in FIG. 6(B), the adhering unit 290 is moved a predetermined first distance in a first direction (here, from left to right in the long-side direction Y) by the long-side direction movement mechanism. The first distance is longer than the length of the liquid inlet 15 in the long-side direction Y. As a result, when the guide roller 211 rotates, the adhesive tape 90 is pulled out from the supply reel by the first distance and fed through the tape supply path 213 to the vicinity of the adhering roller 221. As a result, the adhesive tape 90 is sequentially supplied to the adhering roller 221. The adhesive tape 90 is pressed against the upper surface 14u of the lid 14 by the adhering roller 221 and is adhered to the upper surface 14u so as to close the liquid inlet 15. In Fig. 6(B), during the joining operation, the angle θ formed between the tape supply path 213 and the lid 14 is 20 to 50°, which makes it possible to preferably achieve stable joining.

[0050] Next, as shown in FIG. 6(C), the tape chuck 214 of the tape supply unit 210 is closed, and the suction pump is driven. As a result, the adhesive tape 90 is fixed to the tape supply path 213 again. Next, as shown by the arrow in FIG. 6(D), the roller support member 212 is moved upward from the joining position by the supply unit moving mechanism. In FIG. 6(D), the roller support member 212 has been moved upward so that the lower end of the guide roller 211 is higher than the upper end of the joining roller 221. As a result, the adhesive tape 90 is raised from the tape supply path 213 between the tape supply unit 210 (more specifically, the tape chuck 214) and the joining roller 221. The raised adhesive tape 90 is in a position extending obliquely upward. Therefore, the raised adhesive tape 90 is caused to curl upward with the joining roller 221 as a fulcrum. This makes it possible to more reliably raise a portion of the adhesive tape 90.

[0051] Next, as shown in FIG. 6(E), the cutting mechanism moves the cutter 231 to a cutting position diagonally downward. At the cutting position, the lower end 231d of the cutter 231 is positioned lower than the lower end of the guide roller 211. The lower end 231d of the cutter 231 is positioned at approximately the same height as the lower end of the joining roller 221. In the long side direction Y, the lower end 231d of the cutter 231 is positioned to the right of the guide roller 211 (forward in the direction of travel). Therefore, the adhesive tape 90 is cut between the tape supply unit 210 (more specifically, the tape chuck 214) and the joining roller 221. In FIG. 6(E), the roller support member 212 has been moved upward, so that the angle between the cutter 231 and the adhesive tape 90 is approximately perpendicular (90°±5°) in a side view. This allows for stable cutting.

[0052] Next, as shown by the arrow in FIG. 6(F), the joining unit 290 is moved a predetermined second distance in the first direction (here, from left to right in the long-side direction Y) by the long-side direction moving mechanism. As a result, the cut portion of the adhesive tape 90 near the joining roller 221 is joined to the upper surface 14u of the lid body 14 by the joining roller 221. The second distance is shorter than the entire length of the lifted portion of the cut adhesive tape 90. The second distance is typically shorter than the first distance. By pressing the edge of the joined portion after cutting the adhesive tape 90, the adhesive tape 90 can be more closely attached to the upper surface 14u of the lid body 14. When the above operations are completed, the cutter 231 is moved upward by the cutter moving mechanism. The joining roller 221 is moved upward from the joining position by the joining unit moving mechanism. Therefore, a portion of the cut adhesive tape 90 is maintained in a lifted state above the upper surface 14u of the lid body 14.

[0053] FIG. 7(A) is a plan view schematically showing the upper surface 14u of the lid 14 after this step. FIG. 7(B) is a schematic longitudinal cross-sectional view taken along line IIV(B)-IIV(B) in FIG. 7(A). As shown in FIG. 7(A), the adhesive tape 90 disposed on the upper surface 14u of the lid 14 is substantially rectangular. The adhesive tape 90 is disposed on the upper surface 14u with the long side of the rectangle aligned with the long side direction Y of the lid 14. However, the planar shape of the adhesive tape 90 is not particularly limited. The adhesive tape 90 is divided into two parts along the long side direction Y: a peripheral edge portion 90a surrounding the liquid injection hole 15, and an extension portion 90b extending from the peripheral edge portion 90a to one side in the long side direction Y (the front side in the traveling direction, the right side in FIG. 7(A)). The extension portion 90b is an example of a "portion distant from the liquid injection hole."

[0054] As shown in FIG. 7(B), peripheral edge 90a closes liquid inlet 15. In peripheral edge 90a, adhesive tape 90 is present above liquid inlet 15 and around the periphery thereof. In peripheral edge 90a, adhesive tape 90 is attached to upper surface 14u of lid 14 and is in close contact with upper surface 14u of lid 14. This prevents spatter from entering inside case body 12 through liquid inlet 15 when lid 14 is welded to case body 12 in a case joining step (step S3) described below.

[0055] The extension portion 90b is spaced apart from the upper surface 14u of the lid 14 and is floating above the upper surface 14u of the lid 14. Due to the presence of the extension portion 90b, the center position of the adhesive tape 90 is shifted to the left in the long side direction Y from the center position of the liquid injection hole 15. This configuration is maintained until the adhesive tape 90 is removed in the opening step (step S4) described below. By having a part of the adhesive tape 90 (extension portion 90b) floating above the upper surface 14u of the lid 14 in this manner, the floating part (extension portion 90b) of the adhesive tape 90 can be used to easily peel off the adhesive tape 90 from the lid 14 in the opening step (step S4).

[0056] In addition, according to the inventors' investigations, when a reusable resin cap is washed and reused instead of adhesive tape 90 as a means for temporarily sealing injection hole 15, as described in Patent Document 2, for example, foreign matter gradually becomes more likely to adhere to the surface of the cap due to wear, and there is a risk of foreign matter being mixed in. Furthermore, when the cap is washed or used repeatedly, it may become deformed, losing its adhesion to injection hole 15 or becoming more likely to move within injection hole 15. By using disposable adhesive tape 90, such situations can be appropriately avoided.

[0057] The case joining process (step S3) is a process of welding the lid 14 to the periphery of the opening of the case body 12. In this process, for example, first, the lid 14 is placed on the opening of the case body 12. Next, the outer peripheral edge of the lid 14 is welded to the inner peripheral edge of the opening of the case body 12 along the entire circumference. The welding process can be performed by a conventionally known method (for example, laser welding). This seals the opening of the case body 12 and integrates the case body 12 and the lid 14. Note that during laser welding, high-temperature molten metal may be generated from the welded area as fine particles (so-called spatter). However, with the technology disclosed herein, the liquid inlet 15 is blocked with adhesive tape 90, which prevents the spatter from entering the inside of the case body 12 through the liquid inlet 15.

[0058] The opening step (step S4) is a step of peeling off the adhesive tape 90 attached to the lid 14. This opens the liquid injection hole 15. FIG. 8 is a schematic diagram illustrating this step. In this embodiment, first, a gripping tool 300 for gripping the adhesive tape 90 is prepared. Use of the gripping tool 300 can improve the productivity and workability of this step. The gripping tool 300 may have a configuration similar to that of a conventionally commonly used gripping tool, and is not particularly limited. In this embodiment, the gripping tool 300 includes a pair of thin blades 310. The blades 310 have a sharp tip on the side facing the adhesive tape 90. This makes it easy to peel off the adhesive tape 90. However, in other embodiments, the adhesive tape 90 can be gripped with a person's fingertips or the like and peeled off from the lid 14 without using the gripping tool 300.

[0059] Next, as shown in FIG. 8 , one blade 310 is inserted between the lid 14 and the portion of the adhesive tape 90 that is lifted from the lid 14 (extension 90b), and the other blade 310 clamps the adhesive tape 90. As a result, the extension 90b of the adhesive tape 90 is gripped by the gripping tool 300. Then, while gripping the adhesive tape 90, the gripping tool 300 is moved horizontally as shown by the arrow in FIG. 8 . As a result, the adhesive tape 90 moves along the lid 14, and the adhesive tape 90 is peeled off from the lid 14 starting from the extension 90b. As described above, gripping the extension 90b makes it easier to peel the adhesive tape 90. Therefore, adhesive residue is less likely to remain around the injection hole 15. Furthermore, as the adhesive tape 90 moves along the lid 14, peeling proceeds little by little in the long side direction Y, stabilizing the peeled area and reducing the occurrence of uneven peeling.

[0060] The leak inspection process (step S5) is a process for evaluating the airtightness of the battery case 10. This process can be performed using a conventionally known procedure. For example, first, a test gas (e.g., helium gas) for leak inspection is filled into the battery case 10 through the open liquid filling hole 15. Then, leakage of the test gas from the battery case 10 is detected using an inspection device. This allows the presence or absence of a leak in the battery case 10 (e.g., the safety valve 17 or the joint between the case body 12 and the lid 14) and the location of the leak to be inspected.

[0061] The liquid injection step (step S6) is a step of injecting the electrolyte into the battery case 10. Here, this is a step of injecting the electrolyte into the case body 12 through the liquid injection hole 15 of the lid 14. The liquid injection may be performed at atmospheric pressure, or may be performed with the pressure inside the battery case 10 reduced, for example, for the purpose of improving the impregnation of the electrolyte into the electrode body 20. This results in the construction of an assembly (a combination of the battery case 10 and the electrode body 20). After the liquid injection, the assembly may be left (held) for a predetermined time. This allows the electrolyte to be distributed evenly, for example, in the long side direction Y of the electrode body 20.

[0062] The main sealing step (step S7) is a step of sealing the liquid inlet 15 with a sealing member 16. In a preferred embodiment, first, gas inside the battery case 10, such as air or gas generated by decomposition of the electrolyte, is exhausted to the outside of the battery case 10. The gas can be exhausted, for example, by reducing the pressure inside the battery case 10. Next, the sealing member 16 is fitted into the liquid inlet 15 while the pressure inside the battery case 10 remains at normal pressure or is reduced. Next, the sealing member 16 and the liquid inlet 15 are welded together to seal the liquid inlet 15. This hermetically seals the battery case 10. In this manner, the electricity storage device 100 can be preferably manufactured.

[0063] The power storage device 100 can be used for a variety of purposes. Suitable applications include, for example, a power source (driving power source) for a motor mounted on a vehicle such as a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), or a battery electric vehicle (BEV). The power storage device 100 can also be used as a storage battery for a small power storage device or the like. The power storage device 100 can also be used in the form of a battery pack, typically consisting of a plurality of devices connected in series and / or parallel.

[0064] Although the preferred embodiment of the present invention has been described above, the above embodiment is merely an example. The present invention can be implemented in various other forms. The present invention can be implemented based on the contents disclosed in this specification and the technical common sense in the relevant field. The technology described in the claims includes various modifications and alterations of the above-exemplified embodiment. For example, it is possible to replace part of the above-described embodiment with other modifications, or to add other modifications to the above-described embodiment. Furthermore, if a technical feature is not described as essential, it may be deleted as appropriate.

[0065] For example, in the above-described embodiment, in the temporary sealing step (step S2), as shown in FIG. 6(D), the guide roller 211 is moved upward to form a curve in the adhesive tape 90, causing a portion of the adhesive tape 90 (extended portion 90b) to be raised. However, this is not limited to this. In a modified example, for example, the adhesive tape 90 may be curved when wound on a supply reel, causing a portion of the adhesive tape 90 to be raised, or the adhesive tape 90 may be manually bent to cause a portion of the adhesive tape 90 to be raised. In addition, an adhesive layer may not be provided on the extended portion 90b.

[0066] For example, in the above-described embodiment, in the opening step (step S4), the gripper 300 grips the portion of the adhesive tape 90 that is lifted from the lid 14 (extended portion 90b), and the adhesive tape 90 is peeled off. However, the present invention is not limited to this.

[0067] FIG. 9 is a diagram corresponding to FIG. 8 but relating to a modified example. In this modified example, a suction device 400 is first prepared instead of the gripping tool 300. Using the suction device 400 reduces the risk of damaging the lid 14. The suction device 400 may have a configuration similar to that of a conventional device commonly used, and is not particularly limited. The suction device 400 includes a suction unit 410 and a movement mechanism (not shown). The suction unit 410 is provided on the surface facing the adhesive tape 90 (the lower surface in FIG. 9). The outer shape of the suction unit 410 is preferably smaller than the outer shape of the extension portion 90b. Although not shown, the suction unit 410 has multiple suction holes for adsorbing the adhesive tape 90 (specifically, the extension portion 90b). The suction holes are connected to a suction pump (not shown). The suction device 400 controls suction and release by controlling the activation and deactivation of the suction pump. The movement mechanism moves (here, moves down and up) the suction part 410 toward the adhesive tape 90 and away from the adhesive tape 90. The movement mechanism is, for example, a piston cylinder.

[0068] Next, the moving mechanism lowers the suction portion 410 so that the suction portion 410 abuts against the portion of the adhesive tape 90 that is lifted from the lid 14 (extension 90b). In this state, the suction pump is driven, so that the extension 90b is sucked into and adsorbed by the suction portion 410, as shown by the arrow in FIG. 9. Next, as shown by the arrow in FIG. 9, the moving mechanism moves the suction portion 410 upward or obliquely upward, with the extension 90b being adsorbed. This causes the extension 90b to be pulled up together with the suction portion 410, and the adhesive tape 90 is peeled off from the lid 14, starting from the extension 90b. In this manner, the liquid injection hole 15 may be opened.

[0069] As described above, specific aspects of the technology disclosed herein include those described in the following sections. Item 1: A method for manufacturing an electricity storage device including an electrode body, an electrolyte, a case body having an opening and accommodating the electrode body and the electrolyte, and a lid body having a liquid injection hole and closing the opening of the case body, the method comprising: a temporary sealing step of attaching adhesive tape to the lid body so as to close the liquid injection hole; and an unsealing step of peeling off the adhesive tape attached to the lid body, wherein in the temporary sealing step, the adhesive tape is attached to a peripheral portion of the liquid injection hole, while at least a portion of the adhesive tape is left floating above the lid body in a portion away from the liquid injection hole. Item 2: The manufacturing method according to Item 1, wherein the adhesive tape is rectangular, and in the temporary sealing step, one end of the rectangular tape in the long side direction is raised above the lid. Item 3: The manufacturing method according to item 1 or 2, wherein in the temporary sealing step, a tape application device is provided that includes an application unit that is movable in a first direction along the surface of the lid body, and the application unit includes an application roller that presses the adhesive tape against the surface of the lid body, and a tape supply unit that is positioned forward of the application roller in the first direction and supplies the adhesive tape to the application roller, and the adhesive tape is applied to the lid body by an application operation in which the adhesive tape is sequentially supplied from the tape supply unit and pressed by the application roller while the application unit is moved in the first direction. Item 4: The manufacturing method described in Item 3, wherein the tape supply unit is equipped with a supply unit moving mechanism that can move upward, and after the joining operation, the tape supply unit is moved upward, causing the adhesive tape between the tape supply unit and the joining roller to curl upward. Item 5: The manufacturing method according to item 3 or 4, wherein the joining unit further includes a cutter that cuts the adhesive tape, and the adhesive tape between the tape supply unit and the joining roller is cut by the cutter. Item 6: The manufacturing method according to any one of items 3 to 5, wherein the tape supply unit includes a guide roller that guides the adhesive tape to the vicinity of the applying roller, a tape supply path that passes the adhesive tape over the guide roller, a suction mechanism that is provided in the tape supply path and suctions the adhesive tape, and a tape chuck that is provided in the tape supply path and supports the adhesive tape from below, and during the applying operation, the suction mechanism is stopped and the tape chuck is opened, and the applying unit is moved in the first direction. Item 7: The manufacturing method according to Item 6, wherein in the joining operation, an angle formed between the tape supply path and the lid is set to 20° or more and 50° or less. Item 8: The manufacturing method according to any one of items 1 to 7, wherein in the unsealing step, the portion of the adhesive tape that has been lifted from the lid body in the temporary sealing step is sucked by a suction device, and the adhesive tape is peeled off starting from the lifted portion. Item 9: The manufacturing method according to any one of items 1 to 7, wherein in the opening step, the portion of the adhesive tape that has been lifted from the lid body in the temporary sealing step is gripped, and the adhesive tape is peeled off starting from the lifted portion. Item 10: The manufacturing method according to Item 9, wherein in the opening step, the adhesive tape is peeled off by moving the adhesive tape along the lid body. Item 11: The manufacturing method according to any one of items 1 to 10, further comprising a case joining step of welding the lid body to the periphery of the opening of the case body between the temporary sealing step and the unsealing step. Item 12: The manufacturing method according to any one of items 1 to 11, further comprising: a liquid injection step of injecting the electrolyte into the inside of the case body through the liquid injection hole after the opening step; and a main sealing step of sealing the liquid injection hole with a sealing member after the liquid injection step. [Explanation of symbols]

[0070] 10 Battery case 12 Case body 14 Lid 15 Liquid injection hole 20 Electrode body 90 adhesive tape 90a Periphery 90b Extension part 100 Energy storage device 210 Tape supply unit 211 Guide roller 213 Tape supply route 214 Tape zipper 220 Adhesive part 221 Pasting roller 230 Ribbon Cutting Ceremony 231 Cutter 290 units 300 Gripping tool 400 Adsorption device 410 Adsorption part

Claims

1. A method for manufacturing an electricity storage device including: an electrode body; an electrolyte; a case body having an opening and accommodating the electrode body and the electrolyte; and a lid body having a liquid injection hole and closing the opening of the case body, a temporary sealing step of attaching an adhesive tape to the lid body so as to close the liquid injection hole; an opening step of peeling off the adhesive tape attached to the lid body; Including, In the temporary sealing step, a tape application device including an application unit movable in a first direction along the surface of the lid body is provided; the joining unit includes: an joining roller that presses the adhesive tape onto a surface of the lid body; and a tape supply unit that is disposed forward of the joining roller in the first direction and supplies the adhesive tape to the joining roller; the tape supply unit includes a supply unit moving mechanism that is movable upward; While moving the joining unit in the first direction, the adhesive tape is sequentially supplied from the tape supply unit and pressed by the joining roller to join the adhesive tape to the peripheral edge of the liquid injection hole; and After the adhering operation, the tape supply unit is moved upward, and an operation is performed to cause the adhesive tape between the tape supply unit and the adhering roller to curl upward, so that at least a part of the adhesive tape at a portion away from the liquid injection hole is raised above the lid body. A method for manufacturing an electricity storage device.

2. The adhesive tape has a rectangular shape, and in the temporary sealing step, one end of the rectangular shape in a long side direction is raised above the lid body. The method of claim 1.

3. the joining unit further includes a cutter that cuts the adhesive tape, the adhesive tape between the tape supply unit and the joining roller is cut by the cutter; The method according to claim 1 or 2.

4. the tape supply unit further includes a guide roller that guides the adhesive tape to the vicinity of the joining roller, a tape supply path that passes the adhesive tape over the guide roller, a suction mechanism that is provided on the tape supply path and that suctions the adhesive tape, and a tape chuck that is provided on the tape supply path and that supports the adhesive tape from below, In the joining operation, the adhering unit is moved in the first direction while the suction mechanism is stopped and the tape chuck is opened. The method according to claim 1 or 2.

5. In the joining operation, an angle formed between the tape supply path and the lid is set to be equal to or greater than 20° and equal to or less than 50°. The method of claim 4.

6. In the unsealing step, the portion of the adhesive tape that has been lifted from the lid body in the temporary sealing step is sucked by a suction device, and the adhesive tape is peeled off starting from the lifted portion. The method according to claim 1 or 2.

7. In the unsealing step, the portion of the adhesive tape that has been lifted from the lid body in the temporary sealing step is gripped, and the adhesive tape is peeled off starting from the lifted portion. The method according to claim 1 or 2.

8. In the opening step, the adhesive tape moves along the lid body, thereby peeling off the adhesive tape. The method of claim 7.

9. a case joining step of welding the lid to a periphery of the opening of the case body between the temporary sealing step and the unsealing step, The method according to claim 1 or 2.

10. a liquid injection step of injecting the electrolyte into the case body through the liquid injection hole after the opening step; a main sealing step of sealing the liquid injection hole with a sealing member after the liquid injection step; further comprising: The method of claim 9.

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