Method for manufacturing an electricity storage device

Abstract

To provide a technique that reduces the diffusion angle of an electrolyte diffused from a nozzle hole of a liquid injection nozzle.SOLUTION: A manufacturing method disclosed herein includes injecting an electrolyte into an assembly. For the injection, a liquid injection device including a liquid injection nozzle 81 having a nozzle tube portion 81A and a nozzle hole 81h on a side surface of the nozzle tube portion 81A is used. The nozzle tube portion 81A includes a main body 811 with an open tip, and a cap 812 inserted into the opening of the main body 811. The nozzle tube portion 81A includes the nozzle hole 81h on the side surface at the tip side of the main body 811. The cap 812 is open at a first end 8121 located inside the main body 811, and closed at a second end 8122 opposite to the first end 8121. The cap 812 is chamfered at an inner edge of the first end 8121. The cap 812 has a through-hole 812h on a side surface on the second end 8122 side. The nozzle hole 81h and the through-hole 812h overlap with each other.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] The battery manufacturing method disclosed in JP 2021-93318 A includes using a liquid injection device to inject an electrolyte into a battery case of a battery assembly in which an electrode body is housed in a battery case having a liquid injection port. The liquid injection device is equipped with a liquid injection nozzle having a cylindrical nozzle tube portion and a nozzle hole formed by an elongated hole opening along the circumferential direction on the side of the nozzle tube portion. When injecting the electrolyte, the liquid injection nozzle is inserted into the battery case so that the nozzle hole reaches the inside of the battery case, and the electrolyte is injected into the battery case through the nozzle hole. The document states that this configuration can shorten the liquid injection time in the liquid injection step of injecting the electrolyte into the battery case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-93318 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the present inventors wish to reduce the diffusion angle of the electrolyte solution that diffuses from the nozzle hole of the injection nozzle when the electrolyte solution is injected. [Means for solving the problem]

[0005] The technology disclosed herein provides a method for manufacturing an electricity storage device including an electrode assembly, an electrolyte, and a case. The case accommodates the electrode assembly and the electrolyte. The case includes an exterior body having an opening, an exterior body having an electrolyte injection hole, and a sealing plate for the opening. The manufacturing method includes preparing an assembly in which the electrode assembly is accommodated in the case, and injecting the electrolyte into the assembly. The injection uses an injection device including a cylindrical injection nozzle having a nozzle tube portion with a closed tip and a nozzle hole opening on a side surface of the nozzle tube portion. The injection is performed by inserting the injection nozzle into the injection hole so that the nozzle hole reaches the inside of the case of the assembly, and injecting the electrolyte into the case through the nozzle hole. In the injection device, the nozzle tube portion includes a cylindrical main body having an open tip and a cylindrical cap inserted into the opening at the tip of the main body. The nozzle tube portion has a nozzle hole on a side surface of the main body near the tip. The cap is open at a first end disposed inside the body and closed at a second end opposite the first end. The cap is chamfered at the inner edge of the first end. The cap has a through-hole on the side surface on the second end side. The nozzle hole and the through-hole overlap. With this configuration, the diffusion angle of the electrolyte diffusing from the nozzle hole of the injection nozzle can be reduced when the electrolyte is injected. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view of an electricity storage device 1. FIG. [Figure 2] FIG. 2 is a schematic cross-sectional view of the electricity storage device 1. As shown in FIG. [Figure 3] FIG. 3 is a schematic diagram of the electrode body 20. [Figure 4] FIG. 4 is a schematic diagram illustrating a part of the manufacturing method according to one embodiment. [Figure 5] FIG. 5 is a schematic partial cross-sectional view of the liquid injection nozzle 81. As shown in FIG. [Figure 6] FIG. 6 is a schematic diagram illustrating the diffusion angle θz of the electrolyte. DETAILED DESCRIPTION OF THE INVENTION

[0007] An embodiment of the technology disclosed herein will be described below. The embodiment described herein is not intended to limit the technology disclosed herein. The technology disclosed herein is not limited to the embodiment described herein unless otherwise specified. The drawings are schematic and do not necessarily reflect the actual product. Furthermore, identical reference symbols are used for components and parts performing the same function, and redundant explanations will be omitted. The reference symbols "R," "L," "U," "D," "F," and "Rr" in the drawings represent "right," "left," "up," "down," "front," and "rear," respectively. Furthermore, the notation "A to B" indicating a numerical range means "greater than A and less than B" unless otherwise specified, and also encompasses the meaning of "greater than A and less than B."

[0008] In this specification, the term "electricity storage device" refers to a device in which charging and discharging occur by the movement of charge carriers between a pair of electrodes (positive and negative electrodes) via an electrolyte. Such electricity storage devices include secondary batteries such as lithium ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries; and capacitors such as lithium ion capacitors and electric double layer capacitors. In the following, an embodiment will be described in which a lithium ion secondary battery is used as an example of the above-mentioned electricity storage device.

[0009] Fig. 1 is a perspective view of an electricity storage device 1. Fig. 2 is a schematic cross-sectional view of the electricity storage device 1. Fig. 2 shows the cross-sectional structure of the electricity storage device 1 along a first surface 12b of a case 10. As shown in Figs. 1 and 2, the electricity storage device 1, which is the target of production by the production method disclosed herein, includes a case 10, an electrode body 20, a positive electrode terminal 30, a negative electrode terminal 40, various insulating members, and an electrolyte solution (not shown).

[0010] The case 10 is, for example, a member that houses the electrode assembly 20 and the electrolyte. Although not particularly limited, the case 10 may be made of aluminum or an aluminum alloy, for example, from the viewpoint of reducing weight and ensuring the required rigidity.

[0011] As shown in FIGS. 1 and 2, the case 10 has an exterior body 12 and a sealing plate 14. The exterior body 12 is, for example, the main body of the case 10, which houses the electrode assembly 20 therein. In this embodiment, the exterior body 12 has an opening 12h, a bottom surface 12a, a pair of opposing first surfaces 12b, and a pair of opposing second surfaces 12c. The bottom surface 12a here faces the opening 12h. The bottom surface 12a here is rectangular and has a pair of opposing long sides and a pair of opposing short sides. The pair of opposing first surfaces 12b are surfaces extending from the pair of opposing long sides of the bottom surface 12a. The pair of opposing second surfaces 12c are surfaces extending from the pair of opposing short sides of the bottom surface 12a. In this specification, the terms "rectangular" or "rectangle" include shapes in which straight long and short sides are joined to each other via a curve, shapes in which at least one of the long and short sides is not straight but is curved, uneven, or bent and composed of multiple straight or curved lines, etc.

[0012] Opening 12h is, for example, a location where sealing plate 14 is attached. Here, opening 12h is formed by being surrounded by the upper edges of the pair of first surfaces 12b and the upper edges of the pair of second surfaces 12c, and has a rectangular shape. By fitting sealing plate 14 into opening 12h and joining (for example, welding) it, exterior body 12 and sealing plate 14 are integrated, and case 10 is hermetically sealed.

[0013] The sealing plate 14 is, for example, a flat plate-like member that seals the opening 12h. Therefore, the shape of the sealing plate 14 may correspond to the shape of the opening 12h. In this embodiment, the sealing plate 14 is rectangular. Here, when the sealing plate 14 is attached to the opening 12h, the sealing plate 14 faces, for example, the bottom surface 12a. The sealing plate 14 has a drain valve 17 and a liquid inlet 15. The drain valve 17 is, for example, a thin-walled portion. Here, the drain valve 17 is configured to break when the pressure inside the case 10 exceeds a predetermined value, thereby discharging gas inside the case 10 to the outside. The liquid inlet 15 is a portion through which the electrolyte is injected. As shown in FIG. 1 , a sealing member 16 is attached to the liquid inlet 15. The sealing member 16 may be made of, for example, metal.

[0014] The sealing plate 14 may have, for example, mounting holes (through holes) to which electrode terminals are attached. The sealing plate 14 may have, for example, a mounting hole to which the positive electrode terminal 30 is attached and a mounting hole to which the negative electrode terminal 40 is attached.

[0015] 3 is a schematic diagram of the electrode assembly 20. The electrode assembly 20 is a wound electrode assembly in which, for example, a sheet-shaped positive electrode 22 and a sheet-shaped negative electrode 24 are stacked with a separator 23 interposed therebetween and wound in the sheet longitudinal direction LD. The electrode assembly 20 can be produced, for example, by winding the positive electrode 22, the negative electrode 24, and the separator 23 into a cylindrical body and press-molding the cylindrical body. Therefore, the electrode assembly 20 has a flat shape.

[0016] In this embodiment, the electrode assembly 20 has a pair of flat surfaces 20a, a pair of end surfaces 20b, and a pair of end surfaces 20c. In the embodiment shown in FIG. 2, the flat surfaces 20a are rectangular surfaces located at both ends in the stacking direction of the positive electrode 22 and the negative electrode 24. The flat surfaces 20a face the first surface 12b. The end surfaces 20b are the lamination surfaces of the uncoated portions 22c1 of the positive electrode current collector foil 22c and are open surfaces. The end surfaces 20c are the lamination surfaces of the uncoated portions 24c1 of the negative electrode current collector foil 24c and are open surfaces. One end surface 20b of the electrode assembly 20 faces one second surface 12c (the left second surface 12c in FIG. 1), and the other end surface 20c faces the other second surface 12c (the right second surface 12c in FIG. 1). In this embodiment, the electrode body 20 is housed in the exterior body 12 so that the winding axis direction WD is approximately parallel to the left-right direction of the electricity storage device 1. The winding axis WL of the electrode body 20 is approximately perpendicular to the first surface 12b and the second surface 12c, and is also approximately parallel to the sealing plate 14.

[0017] 3, the positive electrode 22 has a long, 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. A protective layer (not shown) may be provided on one side edge portion in the winding axis direction WD of the positive electrode 22, as necessary. Materials used in this type of electricity storage device (in this embodiment, a lithium-ion secondary battery) may be used as constituent materials of the positive electrode active material layer 22a and the protective layer without any particular limitation.

[0018] A band-shaped uncoated portion 22c1 is provided along the longitudinal direction LD at one end of the positive current collector foil 22c in the winding axis direction WD (the left end in FIG. 3). The uncoated portion 22c1 is a part of the positive current collector foil 22c. The uncoated portion 22c1 is a portion of the positive current collector foil 22c that is not coated with the positive electrode active material layer 22a. In this embodiment, the uncoated portion 22c1 protrudes further in the winding axis direction WD than the separator 23. The uncoated portion 22c1 is laminated at one end of the winding axis direction WD (the left end in FIG. 3). As shown in FIG. 2, a connecting piece 31b is joined to the uncoated portion 22c1.

[0019] 3, the negative electrode 24 has a long, 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. As a constituent material of the negative electrode active material layer 24a, any material used in this type of electricity storage device (in this embodiment, a lithium ion secondary battery) may be used without any particular limitation.

[0020] A band-shaped uncoated portion 24c1 is provided along the longitudinal direction LD at one end of the negative electrode current collector foil 24c in the winding axis direction WD (the right end in FIG. 3). The uncoated portion 24c1 is a part of the negative electrode current collector foil 24c. The uncoated portion 24c1 is a portion of the negative electrode current collector foil 24c where the negative electrode active material layer 24a is not formed. In this embodiment, the uncoated portion 24c1 protrudes further in the winding axis direction WD than the separator 23. For example, the uncoated portion 24c1 is laminated at one end of the winding axis direction WD (the right end in FIG. 3). As shown in FIG. 2, a connecting piece 41b is joined to the uncoated portion 24c1.

[0021] The separator 23 is a member that insulates the positive electrode active material layer 22a of the positive electrode 22 from the negative electrode active material layer 24a of the negative electrode 24. In this embodiment, the separator 23 forms the outer surface of the electrode body 20. The separator 23 is, for example, a porous sheet made of a resin such as a polyolefin resin, such as polyethylene (PE) or polypropylene (PP).

[0022] The positive electrode terminal 30 is, for example, a member electrically connected to the positive electrode 22 of the electrode assembly 20. The positive electrode terminal 30 is made of, for example, aluminum or an aluminum alloy. As shown in FIG. 2, the positive electrode terminal 30 is inserted through a mounting hole and disposed on both the outside and inside of the exterior body 12. Here, the positive electrode terminal 30 includes a first conductive portion 31 and a second conductive portion 32. The first conductive portion 31 is, for example, disposed on the inside of the case 10. In the embodiment shown in FIG. 2, the first conductive portion 31 includes a base 31a and a connecting piece 31b. The base 31a is flat and disposed along the inner surface 142 of the sealing plate 14. The connecting piece 31b is flat and connected to the base 31a, extends toward the bottom surface 12a, and is joined to the uncoated portion 22c1. The second conductive portion 32 is, for example, disposed on the outside of the case 10. 2, the second conductive part 32 has a flat plate shape and is arranged along the outer surface 141 of the sealing plate 14. The first conductive part 31 and the second conductive part 32 are connected by a cylindrical shaft part (not shown).

[0023] The negative electrode terminal 40 is, for example, a member electrically connected to the negative electrode 24 of the electrode body 20. The negative electrode terminal 40 is made of, for example, copper or a copper alloy. The negative electrode terminal 40 may have a configuration similar to that of the positive electrode terminal 30. Therefore, a description of the configuration of the negative electrode terminal 40 will be omitted here. Note that with respect to the negative electrode terminal 40, reference numeral "41" in FIG. 2 denotes a first conductive part, reference numeral "41a" denotes a base, reference numeral "41b" denotes a connecting piece, and reference numeral "42" denotes a second conductive part.

[0024] In the embodiment shown in FIG. 2 , the various insulating members include a first insulating member 71, a second insulating member 72, and an insulating film (not shown). The first insulating member 71 and the second insulating member 72 are, for example, members that insulate the electrode terminal and the sealing plate 14. Here, the first insulating member 71 is disposed between the second conductive portion (32, 42) and the sealing plate 14. Here, the second insulating member 72 is disposed between the base (31 a, 41 a) and the sealing plate 14. From the viewpoint of insulating between the shaft portion and the inner wall surface of the mounting hole, for example, a portion of the first insulating member 71 or a portion of the second insulating member 72 may be disposed in that location. The insulating film is, for example, a member that insulates the electrode assembly 20 and the exterior body 12. The insulating film is, for example, bag-shaped and may be disposed in the case 10 while enclosing the electrode assembly 20.

[0025] The electrolyte solution contains, for example, an electrolyte salt and a non-aqueous solvent. Examples of the electrolyte salt include LiPF6. The concentration of the electrolyte salt in the electrolyte solution is, for example, 0.7 mol / L to 1.3 mol / L. The non-aqueous solvent may be, for example, a carbonate. Examples of carbonates include ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), monofluoroethylene carbonate (MFEC), difluoroethylene carbonate (DFEC), monofluoromethyl difluoromethyl carbonate (F-DMC), trifluorodimethyl carbonate (TFDMC), etc. These may be used alone or in combination of two or more.

[0026] The electricity storage device 1 can be used for a variety of purposes, and is particularly preferably used as a power source (driving power source) for motors mounted on vehicles such as passenger cars, trucks, etc. The type of vehicle is not particularly limited, but suitable examples include plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs).

[0027] Fig. 4 is a schematic diagram illustrating a part of a manufacturing method according to one embodiment. Fig. 4 shows a state in which an electrolyte solution is being injected into the assembly 1A by a liquid injection device 80. The manufacturing method for the electricity storage device 1 includes, for example, preparing the assembly 1A and injecting the electrolyte solution into the assembly 1A.

[0028] Preparing the assembly 1A includes, for example, preparing an assembly 1A in which an electrode body 20 is housed in a case 10 (see FIG. 4). Here, for example, first, a first insulating member 71 and a second insulating member 72 are attached to a sealing plate 14, and then a positive electrode terminal 30 and a negative electrode terminal 40 are attached to form a first combined body (see FIG. 2). Next, the electrode body 20 is attached to the first combined body to form a second combined body. Next, the electrode body 20 of the second combined body is wrapped in an insulating film. Next, the electrode body 20 wrapped in the insulating film is housed in an exterior body 12. Then, the sealing plate 14 is fitted into an opening 12h of the exterior body 12, and the two are welded together to form the assembly 1A. Note that the electrode body 20 may be one produced by a conventionally known method, for example.

[0029] Injecting the electrolyte includes injecting the electrolyte into the case 10 of the assembly 1A using an injection device 80. As shown in FIG. 4, the injection device 80 includes an injection nozzle 81, a valve 82, and a tank 83. The tank 83 is, for example, a container that stores the electrolyte. In this embodiment, the tank 83 is connected to the injection nozzle 81 via a pipe 80A. The valve 82, for example, adjusts the supply of the electrolyte from the tank 83. The valve 82 is provided on the pipe 80A that connects the tank 83 and the injection nozzle 81.

[0030] FIG. 5 is a schematic partial cross-sectional view of the liquid injection nozzle 81. As shown in FIG. 5, the liquid injection nozzle 81 is cylindrical and has a nozzle pipe portion 81A and a nozzle hole 81h. In this embodiment, the tip of the nozzle pipe portion 81A is closed. The nozzle pipe portion 81A includes a main body 811 and a cap 812. The nozzle pipe portion 81A has a nozzle hole 81h on the side surface on the tip side of the main body 811. The main body 811 is cylindrical and has an open tip. In this embodiment, with respect to the liquid injection nozzle 81, the nozzle pipe portion 81A, and the main body 811 of the nozzle pipe portion 81A, the "tip" refers to the end of the liquid injection nozzle 81 in the insertion direction P of the liquid injection nozzle 81 into the case 10 when injecting the electrolyte. In the embodiments shown in FIGS. 4 and 5, the insertion direction P is a direction from top (U) to bottom (D).

[0031] As shown in FIG. 5, the main body 811 has a nozzle hole 81h on its side surface on the tip side. Here, the nozzle hole 81h is a through-hole, and is a portion that ejects the electrolyte in the nozzle pipe section 81A to the outside of the nozzle pipe section 81A. In the embodiment shown in FIG. 5, the main body 811 has two nozzle holes 81h on its side surface on the tip side, at positions that are symmetrical around the axis of the nozzle pipe section 81A. The nozzle hole 81h is, for example, an elongated hole. The nozzle hole 81h is, for example, an elongated hole in which a pair of opposing straight lines (straight lines connecting the arcs at both ends) extend in the circumferential direction of the main body 811.

[0032] As shown in Fig. 5, the cap 812 is cylindrical and is inserted into the opening at the tip of the main body 811. Here, the cap 812 is open at a first end 8121 and closed at a second end 8122. In the form shown in Fig. 5, the first end 8121 is disposed inside the main body 811. The second end 8122 is an end opposite to the first end 8121 and is disposed on the tip side of the main body 811.

[0033] As shown in FIG. 5 , the cap 812 is chamfered at the inner edge of the first end 8121. In this embodiment, the cap 812 has a tapered surface 812t1 at the inner edge of the first end 8121 that slopes inward toward the second end 8122. Here, the tapered surface 812t1 is an inclined surface created by chamfering. The inclination angle θ1 of the tapered surface 812t1 is, for example, 5 to 70 degrees, preferably 10 to 60 degrees, more preferably 15 to 50 degrees, and even more preferably 20 to 40 degrees. In this embodiment, the "inclination angle θ1" refers to the angle between the outer peripheral surface 812a of the cap 812 and the tapered surface 812t1 in a cross-sectional view taken along the axial direction of the cap 812. In this embodiment, the "axial direction" of the liquid injection nozzle 81 or its constituent members refers to the direction along the axis SC of the liquid injection nozzle 81. Here, the "axial direction of the cap 812" refers to the direction along the axis SC.

[0034] As shown in FIG. 5, the cap 812 has a through hole 812h on its side surface on the second end 8122 side. The through hole 812h overlaps with the nozzle hole 81h. The through hole 812h is, for example, a portion through which the electrolytic solution in the nozzle pipe portion 81A is ejected to the outside of the nozzle pipe portion 81A. In the embodiment shown in FIG. 5, the cap 812 has one through hole 812h on its side surface on the second end 8122 side at positions overlapping with the two nozzle holes 81h. Here, the cap 812 has two through holes 812h. In this embodiment, the through hole 812h has the same shape as the nozzle hole 81h. The through hole 812h is, for example, an elongated hole. The through hole 812h is, for example, an elongated hole with a pair of opposing straight lines (straight lines connecting the arcs at both ends) extending in the circumferential direction of the cap 812.

[0035] In the embodiment shown in FIG. 5, the cap 812 has a conically recessed bottom 812t2 on the second end 8122 side. In this embodiment, the bottom 812t2 is configured by a tapered surface that protrudes inward of the cap 812 on the second end side. The tip angle θ2 of the bottom 812t2 may be, for example, 80 to 160 degrees, preferably 90 to 150 degrees, and more preferably 100 to 140 degrees. In this embodiment, the "tip angle θ2 of the bottom 812t2" refers to an angle obtained by connecting two boundaries B1 between the inner circumferential surface 812b of the cap 812 and the bottom 812t2 with the deepest part B2 of the bottom 812t2 in a cross-sectional view along the axial direction of the cap 812 (see FIG. 5).

[0036] When injecting using the injection device 80, for example, the injection nozzle 81 is inserted into the injection hole 15 so that the nozzle hole 81h reaches the inside of the case 10 of the assembly 1A, and the electrolyte is injected into the case 10 through the nozzle hole 81h. From the viewpoint of preventing damage to the electrode body 20, the injection nozzle 81 is preferably inserted into the case 10 so that the nozzle hole 81h and the tip of the injection nozzle 81 are positioned between the inner surface 142 of the sealing plate 14 (see FIGS. 2 and 4 ) and the upper end 20e of the electrode body 20. From the viewpoint of preventing the electrolyte from adhering to the inner surface 142 of the sealing plate 14, the injection nozzle 81 is preferably inserted into the case 10 so that the nozzle hole 81h is sandwiched between insulating films inside the case 10.

[0037] The manufacturing method may include, for example, injecting an electrolyte into the assembly 1A and then sealing the inlet 15. To seal the inlet 15, for example, a sealing member 16 is attached to the inlet 15, and the outer surface 141 (see FIGS. 2 and 4) of the sealing plate 14 is joined to the sealing member 16. The method for joining the sealing plate 14 and the sealing member 16 may be any conventionally known method, such as ultrasonic welding, resistance welding, or laser welding. The manufacturing method may also include, for example, initially charging the assembly 1A after sealing the inlet 15, and performing an aging treatment on the assembly 1A after the initial charge. In this way, a usable electricity storage device 1 can be manufactured.

[0038] As described above, the technology disclosed herein provides a method for manufacturing an electricity storage device 1 including an electrode assembly 20, an electrolyte, and a case 10. The case 10 accommodates the electrode assembly 20 and the electrolyte. The case 10 includes an exterior body 12 having an opening 12h, an exterior body 12 having an electrolyte injection hole 15, and a sealing plate 14 for the opening 12h. The manufacturing method includes preparing an assembly 1A in which the electrode assembly 20 is accommodated in the case 10, and injecting the electrolyte into the assembly 1A. The injection uses an injection device 80 including an injection nozzle 81 having a cylindrical nozzle tube portion 81A with a closed tip and a nozzle hole 81h opening in a side surface of the nozzle tube portion 81A. The injection involves inserting the injection nozzle 81 into the injection hole 15 so that the nozzle hole 81h reaches the inside of the case 10 of the assembly 1A, and injecting the electrolyte into the case 10 through the nozzle hole 81h. In the liquid injection device 80, the nozzle pipe section 81A includes a cylindrical main body 811 with an open tip and a cylindrical cap 812 inserted into the opening at the tip of the main body 811. The nozzle pipe section 81A has a nozzle hole 81h on the side surface of the main body 811 on the tip side. The cap 812 opens at a first end 8121 disposed inside the main body 811 and is closed at a second end 8122 opposite the first end 8121. The cap 812 is chamfered at the inner edge of the first end 8121. The cap 812 has a through hole 812h on the side surface on the second end 8122 side. The nozzle hole 81h and the through hole 812h overlap. According to this configuration, a manufacturing method can reduce the diffusion angle of the electrolyte injected from the nozzle hole 81h during injection.

[0039] The "diffusion angle of the electrolyte solution injected from the nozzle hole 81h" refers to, for example, the degree to which the electrolyte solution ejected from the nozzle hole 81h is diffused in the axial direction of the injection nozzle 81. Such a diffusion angle is, for example, as shown in FIG. 6. FIG. 6 is a schematic diagram illustrating the diffusion angle θz of the electrolyte solution. The smaller the diffusion angle θz, the smaller the area within the case 10 to which the electrolyte solution adheres. Therefore, if the diffusion angle θz can be reduced, for example, it is possible to prevent the electrolyte solution from adhering to the inner surface 142 of the sealing plate 14.

[0040] The manufacturing method of the electricity storage device 1 includes preparing the assembly 1A and injecting an electrolyte solution into the assembly 1A, and an injection device 80 is used in the injection. The injection device 80 is cylindrical and includes an injection nozzle 81 having a nozzle tube portion 81A with a closed tip and a nozzle hole 81h opening in a side surface of the nozzle tube portion 81A. To inject the electrolyte solution, the injection nozzle 81 is inserted into the injection hole 15 so that the nozzle hole 81h reaches the inside of the case 10 of the assembly 1A. The electrolyte solution is then injected into the case 10 through the nozzle hole 81h. In the injection device 80, by providing the nozzle hole 81h on the side surface of the nozzle tube portion 81A, for example, the electrolyte solution can be injected horizontally relative to the injection nozzle 81 within the case 10. This can prevent the electrolyte solution from directly hitting the electrode body 20, thereby preventing damage to the electrode body 20 due to injection. The nozzle pipe part 81A of the liquid injection device 80 includes a cylindrical main body 811 with an open tip, and a cylindrical cap 812 inserted into the tip of the main body 811. Because the nozzle pipe part 81A is composed of two parts, the main body 811 and the cap 812, the liquid injection nozzle 81 can be manufactured more simply and inexpensively, and ultimately the productivity of the electricity storage device 1 can be improved.

[0041] The nozzle pipe portion 81A has a nozzle hole 81h on a side surface of the tip side of the main body 811. The cap 812 opens at a first end 8121 disposed inside the main body 811 and closes at a second end 8122. This prevents the electrolyte from being poured along the axial direction of the nozzle pipe portion 81A, and at least a portion of the electrolyte supplied to the nozzle pipe portion 81A reaches the second end 8122 of the cap 812 and is then poured into the case 10 through the nozzle hole 81h. At this time, the electrolyte flowing along the inner circumferential surface 812b of the cap 812 and ejected from the nozzle hole 81h and the electrolyte reaching the second end 8122 of the cap 812 and then ejected from the nozzle hole 81h join together at the nozzle hole 81h. In other words, the electrolyte reaching the nozzle hole 81h is ejected from the nozzle hole 81h from mutually different directions. This reduces the diffusion angle of the electrolyte from the nozzle hole 81h.

[0042] The cap 812 is chamfered at the inner edge of the first end 8121. This prevents the electrolyte from being blocked at the boundary between the main body 811 and the cap 812 in the inner cavity of the nozzle pipe portion 81A, making it difficult to flow. The cap 812 has a through-hole 812h on the side surface on the second end 8122 side. The nozzle hole 81h and the through-hole 812h overlap. This allows the electrolyte to be efficiently discharged from the injection nozzle 81 into the case 10.

[0043] The main body 811 may have two nozzle holes 81h on its side surface on the tip side, at positions symmetrical about the axis of the nozzle pipe portion 81A. The cap 812 may have one through-hole 812h on its side surface on the second end 8122 side, at positions overlapping with the two nozzle holes 81h. In other words, the nozzle pipe portion 81A may have two nozzle holes 81h and two through-holes 812h. In this embodiment, the amount of electrolyte solution ejected from the nozzle holes 81h per unit time increases. This reduces the time required to inject the electrolyte solution.

[0044] The cap 812 may have a conically recessed bottom at the second end 8122. By making the bottom 812t2 of the cap 812 have a conically recessed shape, it is possible to control the flow direction and amount of the electrolyte solution toward the nozzle hole 81h. This makes it possible to reduce the diffusion angle of the electrolyte solution from the injection nozzle.

[0045] The tip angle of the bottom 812t2 is preferably 80 degrees or more and 160 degrees or less, which makes it possible to more appropriately achieve the effects of the technology disclosed herein.

[0046] The following describes examples of studies (test examples) conducted by the present inventors regarding the technology disclosed herein. However, these test examples are not intended to limit the technology disclosed herein. Please refer to Figures 5 and 6 as appropriate for the reference numbers of the various parts in the following test examples.

[0047] <Design of evaluation sample> In this study, nozzle pipe portions 81A were fabricated as evaluation samples for Examples 1 to 3 shown in Table 1 below. The height H of the cap 812 in each example (the shortest distance between the first end 8121 and the second end 8122) was 3 mm. The inclination angle θ1 and the tip angle θ2 in each example were as shown in the corresponding columns in Table 1. In Example 3, the inclination angle θ1 being 90 degrees means that the first end 8121 of the cap 812 was not chamfered.

[0048] A test on the diffusion of the electrolyte was conducted for the nozzle pipe portion 81A of each sample. In this test, the electrolyte was discharged from the nozzle hole 81h of the nozzle pipe portion 81A of each sample, and an image showing the electrolyte being discharged from the nozzle hole 81h was obtained. Then, image analysis was performed using image analysis software, and the diffusion angle θz when using the nozzle pipe portion 81A of each sample was calculated. The results are shown in the corresponding column in Table 1.

[0049] [Table 1]

[0050] As shown in Table 1, Example 1 and Example 2, in which the inner edge of first end 8121 of cap 812 was chamfered, had a smaller diffusion angle θz of the electrolyte than Example 3, in which the same portion was not chamfered. Comparing Example 1 and Example 2, Example 2, in which the tip angle θ2 at bottom 812t2 of second end 8122 of cap 812 was relatively large, had a smaller diffusion angle θz of the electrolyte than Example 1, in which the tip angle θ2 was relatively small.

[0051] As described above, specific aspects of the technology disclosed herein include those described in the following sections. Item 1: An electrode body; An electrolyte; a case for accommodating the electrode assembly and the electrolyte solution, the case including an exterior body having an opening and a sealing plate for the opening having an injection hole for the electrolyte solution; A method for manufacturing an electricity storage device comprising: preparing an assembly in which the electrode body is housed in the case; injecting the electrolyte into the assembly; It encompasses The injection of the electrolyte is performed by using an injection device including a cylindrical injection nozzle having a nozzle tube portion with a closed tip and a nozzle hole opened on a side surface of the nozzle tube portion, the injection nozzle is inserted into the injection hole so that the nozzle hole reaches the inside of the case of the assembly, and the electrolyte is injected into the case from the nozzle hole, In the liquid injection device, The nozzle pipe portion is The device comprises a cylindrical body with an open tip and a cylindrical cap inserted into the opening at the tip of the body, The nozzle hole is provided on a side surface of the tip side of the main body, The cap is an opening at a first end disposed inside the body and a closing at a second end opposite the first end; an inner edge of the first end being chamfered; a through hole in a side surface on the second end side, The manufacturing method, wherein the nozzle hole and the through hole overlap. Item 2: the main body has two nozzle holes on a side surface at a tip end thereof, the two nozzle holes being symmetrical about the axis of the nozzle pipe portion; Item 2. The manufacturing method according to item 1, wherein the cap has the through-holes on a side surface on the second end side, one at a time at positions overlapping with the two nozzle holes. Item 3: 3. The manufacturing method according to item 1 or 2, wherein the cap has an internal, conically concave bottom at the second end. Item 4: 4. The method according to any one of items 1 to 3, wherein the tip angle of the bottom is 80 degrees or more and 160 degrees or less.

[0052] Although the embodiments of the technology disclosed herein have been described above, it is not intended that the technology disclosed herein be limited to the above-described embodiments. The technology disclosed herein may also be implemented in other embodiments. The technology described in the claims includes various modifications and alterations of the above-described exemplary embodiments. For example, it is possible to replace part of the above-described embodiments with other modified embodiments, and it is also possible to add other modified embodiments to the above-described embodiments. Furthermore, if a technical feature is not described as essential, it may be deleted as appropriate. [Explanation of symbols]

[0053] 1. Energy storage devices 1A assembly 10 cases 14 Sealing plate 15 Liquid injection hole 16 Sealing member 80 Injection device 81 Injection nozzle 81A Nozzle pipe section 811 Main Unit 812 Cap 812h Through hole 8121 1st end 8122 2nd end 81h Nozzle hole

Claims

1. An electrode body; An electrolyte; a case for accommodating the electrode assembly and the electrolyte solution, the case including an exterior body having an opening and a sealing plate for the opening having an injection hole for the electrolyte solution; A method for manufacturing an electricity storage device comprising: preparing an assembly in which the electrode body is housed in the case; injecting the electrolyte into the assembly; It encompasses The injection of the electrolyte is performed by using an injection device including a cylindrical injection nozzle having a nozzle tube portion with a closed tip and a nozzle hole opened on a side surface of the nozzle tube portion, the injection nozzle is inserted into the injection hole so that the nozzle hole reaches the inside of the case of the assembly, and the electrolyte is injected into the case from the nozzle hole, In the liquid injection device, The nozzle pipe portion is The device comprises a cylindrical body with an open tip and a cylindrical cap inserted into the opening at the tip of the body, The nozzle hole is provided on a side surface of the tip side of the main body, The cap is an opening at a first end disposed inside the body and a closing at a second end opposite the first end; a chamfer at an inner edge of the first end; a through hole in a side surface on the second end side, The manufacturing method, wherein the nozzle hole and the through hole overlap.

2. the main body has two nozzle holes on a side surface at a tip end thereof, the two nozzle holes being symmetrical about the axis of the nozzle pipe portion; The manufacturing method according to claim 1 , wherein the cap has the through-holes on a side surface on the second end side, the through-holes being overlapped with the two nozzle holes, one on each side.

3. The method of claim 1 or 2, wherein the cap has an internal, conically recessed bottom at the second end.

4. The manufacturing method according to claim 3 , wherein the tip angle of the bottom portion is equal to or greater than 80 degrees and equal to or less than 160 degrees.

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