Power storage device and manufacturing method therefor

Abstract

To provide a manufacturing method for a battery device, with which an electrolyte does not easily adhere to a case during liquid injection.SOLUTION: A manufacturing method disclosed herein includes: a preparing step of preparing an assembly including a case 10 which includes an electrolyte injection hole 15 and in which a resin member 17 is attached to the electrolyte injection hole 15; a liquid injection step of injecting an electrolyte through the electrolyte injection hole 15; and a sealing step of sealing the electrolyte injection hole 15 after the liquid injection step. The resin member 17 includes: a shaft part 17s that is hollow and is attached to the electrolyte injection hole 15; a penetration hole 17h; and a liquid receiver 17r extending from the shaft part 17s to the outside of the case 10. In the liquid injection step, the electrolyte is injected while the assembly is disposed such that the liquid receiver 17r of the resin member 17 is located below an opening of the penetration hole 17h, and in the sealing step, the penetration hole 17h is closed by melting the resin member 17.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Conventionally, there has been known an electricity storage device that includes a case having an electrolyte injection hole, an electrode assembly and an electrolyte disposed in the case, and a sealing plug that seals the electrolyte injection hole. Related prior art documents include Patent Documents 1 to 3. For example, Patent Document 1 describes that after electrolyte is injected through the electrolyte injection hole, a sealing plug is inserted into the electrolyte injection hole to close the electrolyte injection hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-195093 [Patent Document 2] Special Publication No. 2015-536033 [Patent Document 3] Japanese Patent Publication No. 2022-034963 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the investigations of the present inventors, when the electrolyte is poured, the electrolyte may drip near the electrolyte pouring hole, causing the case to become dirty or discolored.

[0005] The present invention has been made in view of the above circumstances, and its main object is to provide a method for manufacturing a battery device in which the electrolyte is less likely to adhere to the case during injection. [Means for solving the problem]

[0006] The present invention provides a method for manufacturing an electricity storage device, the method including: a preparation step of preparing an assembly including a case having an electrolyte injection hole and a resin member attached to the electrolyte injection hole and an electrode assembly disposed in the case; a filling step of filling an electrolyte into the case through the electrolyte injection hole; and a sealing step of sealing the electrolyte injection hole after the filling step. The resin member has a hollow shaft attached to the electrolyte injection hole, a through hole penetrating the resin member along the axis of the shaft, and a liquid receiving portion formed integrally with the shaft and extending from the shaft to an outside of the case around at least a portion of the periphery of the through hole. In the filling step, the assembly is placed so that the liquid receiving portion of the resin member is positioned below the opening of the through hole, and the electrolyte is poured into the assembly. In the sealing step, the resin member is melted at least outside the case to seal the through hole.

[0007] According to the present invention, the electrolyte is less likely to adhere to the vicinity of the electrolyte injection hole during the injection process, and the case can be prevented from becoming soiled or discolored. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view schematically illustrating an electricity storage device 100 according to one embodiment. [Figure 2] FIG. 2 is a schematic vertical cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a vertical cross-sectional view schematically showing the vicinity of the electrolyte injection hole. [Figure 4] Figures 4(A) to 4(D) are explanatory diagrams of the manufacturing process, where Figure 4(A) is a diagram equivalent to Figure 3 in the preparation process, Figure 4(B) is a diagram equivalent to Figure 3 in the liquid injection process, Figure 4(C) is a diagram equivalent to Figure 3 at the end of the liquid injection process, and Figure 4(D) is a diagram equivalent to Figure 3 in the sealing process. [Figure 5] FIG. 5 is a perspective view schematically showing the resin member in the preparation step. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the technology disclosed herein will be described below with reference to the drawings as appropriate. Matters other than those specifically mentioned in this specification that are necessary for implementing the technology disclosed herein (for example, the general configuration and manufacturing process of an electricity storage device that does not characterize the technology disclosed herein) can be understood as design matters for a person skilled in the art based on prior art in the relevant field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common technical knowledge in the relevant field. Furthermore, the expression "A to B" indicating a range in this specification means greater than or equal to A and less than or equal to B, and also includes the meanings "preferably greater than A" and "preferably smaller than B."

[0010] <Electricity storage device 100> FIG. 1 is a perspective view of the energy storage device 100. FIG. 2 is a schematic longitudinal cross-sectional view taken along line II-II in FIG. 1. In the following description, the same reference numerals are used to designate components and parts that perform the same functions, and redundant description may be omitted or simplified. The reference numerals F, Rr, L, R, U, and D in the drawings represent front, rear, left, right, top, and bottom, respectively, and the reference numerals X, Y, and Z in the drawings represent the short-side direction, long-side direction perpendicular to the short-side direction, and up-down direction of the energy storage device 100, respectively. The short-side direction X and the long-side direction Y correspond to the horizontal direction, and the up-down direction Z corresponds to the vertical direction. However, these directions are merely used for convenience of description and do not limit the installation form of the energy storage device 100 in any way.

[0011] As shown in Fig. 2, the electricity storage device 100 includes a case 10, an electrode assembly 20, an electrolyte (not shown), a positive electrode terminal 30, a negative electrode terminal 40, and a sealing plug 16. Here, the electricity storage device 100 is a non-aqueous electrolyte secondary battery. The electricity storage device 100 is preferably a lithium ion secondary battery. In this specification, the term "electricity storage device" refers to a general device that can be repeatedly charged and discharged, and is a concept that encompasses secondary batteries such as lithium ion secondary batteries and nickel-metal hydride batteries, and capacitors such as lithium ion capacitors and electric double layer capacitors.

[0012] The case 10 is a housing that houses the electrode assembly 20 and the electrolyte. As shown in FIG. 1, the case 10 has a flat, bottomed, rectangular parallelepiped (rectangular) outer shape. The material of the case 10 may be the same as that conventionally used, and is not particularly limited. The case 10 is preferably made of metal, and more preferably made of, for example, aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0013] 2, in this embodiment, the case 10 includes a rectangular cylindrical case body 12 having a pair of openings 12h at both ends in the long side direction Y, and two sealing plates (lids) 14 that close the pair of openings 12h of the case body 12. The case 10 is integrated by joining (for example, welding) the sealing plates 14 to the peripheries of the pair of openings 12h of the case body 12. The case 10 is hermetically sealed (sealed).

[0014] As shown in FIG. 1 , the case body 12 has a bottom surface 12a, a pair of long side surfaces 12b, and a top surface 12c facing the bottom surface 12a. The bottom surface 12a and the top surface 12c each have a substantially rectangular shape with a pair of short sides and a pair of long sides. The pair of long side surfaces 12b extend from the pair of long sides of the bottom surface 12a and face each other. Here, the long side surfaces 12b have a larger area than the bottom surface 12a and the top surface 12c. Here, the long side surfaces 12b have a larger area than the sealing plate 14. The top surface 12c extends from each of the long sides of the pair of long side surfaces 12b and connects the upper ends of the pair of long side surfaces 12b to each other. The case body 12 is formed, for example, by bending a single metal plate into a rectangular tube shape and joining (for example, welding) the seams.

[0015] 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.

[0016] As shown in FIG. 2, the pair of sealing plates 14 are plate-like members that seal the pair of openings 12h, respectively. The sealing plates 14 are generally rectangular in plan view. The area of ​​the sealing plates 14 is smaller than the bottom surface 12a and the top surface 12c. The pair of sealing plates 14 face each other. A positive electrode terminal 30 and a negative electrode terminal 40 are provided on each of the pair of sealing plates 14. The sealing plate 14 on the side where the positive electrode terminal 30 is provided further has an electrolyte injection hole 15. More specifically, the electrolyte injection hole 15 is provided vertically above (directly above) the positive electrode terminal 30. The sealing plates 14 are an example of a side surface of the case 10. The positive electrode terminal 30 is an example of a first electrode terminal, and the negative electrode terminal 40 is an example of a second electrode terminal. However, in other embodiments, the negative electrode terminal 40 may be the first electrode terminal, and the positive electrode terminal 30 may be the second electrode terminal.

[0017] The electrolyte injection hole 15 is for injecting electrolyte after the sealing plate 14 is assembled to the case body 12. The electrolyte injection hole 15 is a through-hole that penetrates the sealing plate 14 in the long side direction Y. Here, the electrolyte injection hole 15 has a substantially circular shape in a plan view. After the electrolyte is injected, the electrolyte injection hole 15 is sealed with a sealing plug 16. The sealing plug 16 will be described later. In this embodiment, the electrolyte injection hole 15 is provided in the sealing plate 14, but in other embodiments, the electrolyte injection hole 15 may be provided in the case body 12 (for example, on the long side surface 12b).

[0018] In this specification, the term "approximately circular" is not limited to a perfect circle (true circle), but also includes circular shapes (e.g., ellipses) in which the curvature of the arc varies locally, and other shapes derived from perfect circles and circles.

[0019] The positive electrode terminal 30 is attached to the first sealing plate 14 (on the right side in the long side direction Y in FIGS. 1 and 2). The positive electrode terminal 30 is preferably made of metal, and more preferably made of aluminum or an aluminum alloy, for example. As shown in FIG. 2, the positive electrode terminal 30 is electrically connected to the positive electrode of the electrode body 20 (more specifically, the positive electrode tab 22) inside the case 10 via a positive electrode current collecting part 32.

[0020] The negative electrode terminal 40 is attached to the second sealing plate 14 (on the left side in the width direction Y in FIGS. 1 and 2). The negative electrode terminal 40 is preferably made of metal, and more preferably made of copper or a copper alloy, for example. As shown in FIG. 2, the negative electrode terminal 40 is electrically connected to the negative electrode of the electrode body 20 (more specifically, the negative electrode tab 24) inside the case 10 via a negative electrode current collecting part 42.

[0021] The electrode assembly 20 is housed inside the case 10. The configuration and shape of the electrode assembly 20 may be the same as conventional ones and are not particularly limited. The number of electrode assemblies 20 housed inside one case 10 is not particularly limited and may be one or two or more (plural). Although not shown, the electrode assembly 20 typically has a positive electrode and a negative electrode. The positive electrode typically has a positive electrode current collector and a positive electrode active material layer fixed to the positive electrode current collector. The negative electrode typically has a negative electrode current collector and a negative electrode active material layer fixed to the negative electrode current collector. The electrode assembly 20 may be housed inside the case 10 covered with a resin insulating sheet (electrode assembly holder).

[0022] Here, the electrode assembly 20 is a wound electrode assembly formed by stacking a strip-shaped positive electrode and a strip-shaped negative electrode with a strip-shaped separator interposed therebetween and winding them in the longitudinal direction around a winding axis. In this embodiment, the electrode assembly 20 is disposed inside the case 10 with the winding axis oriented approximately parallel to the long side direction Y. However, in other embodiments, the electrode assembly 20 may be a laminated electrode assembly formed by stacking multiple square-shaped (typically rectangular) positive electrodes and multiple square-shaped (typically rectangular) negative electrodes in an insulated state.

[0023] As shown in FIG. 2, a positive electrode tab 22 is provided on the positive electrode of the electrode assembly 20. In this case, the positive electrode tab 22 is part of the positive electrode current collector. In this case, the positive electrode tab 22 is convex and protrudes from the electrode assembly 20 toward one side in the long side direction Y (the right side in FIG. 2). The positive electrode tab 22 is electrically connected to a positive electrode terminal 30. In addition, a negative electrode tab 24 is provided on the negative electrode of the electrode assembly 20. In this case, the negative electrode tab 24 is part of the negative electrode current collector. In this case, the negative electrode tab 24 is convex and protrudes from the electrode assembly 20 toward the other side in the long side direction Y (the left side in FIG. 2). The negative electrode tab 24 is electrically connected to a negative electrode terminal 40.

[0024] The electrolyte may be the same as conventional ones and is not particularly limited. The electrolyte is typically a non-aqueous electrolyte containing a non-aqueous solvent and a supporting salt (electrolyte salt). However, it may also be an aqueous electrolyte containing a water solvent. The non-aqueous solvent contains, for example, carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. The non-aqueous solvent preferably contains a carbonate. In particular, it is preferable that the non-aqueous solvent contains a cyclic carbonate and a chain carbonate. The supporting salt is, for example, a fluorine-containing lithium salt such as lithium hexafluorophosphate (LiPF6). The electrolyte may further contain additives as necessary.

[0025] The sealing plug 16 is attached to the electrolyte injection hole 15 of the case 10 and is a member that closes the electrolyte injection hole 15. The sealing plug 16 is attached to the side of the case 10 (here, the sealing plate 14). More specifically, the sealing plug 16 is attached vertically above (here, directly above) the positive electrode terminal 30. Although details will be described later in the section on the manufacturing method, in this embodiment, the sealing plug 16 is attached to the case 10 (here, the sealing plate 14) by integral molding. However, in other embodiments, the sealing plug 16 may be joined to the case 10 by, for example, friction stir welding or the like, or may be adhered to the case 10 via an adhesive layer (adhesive or the like).

[0026] The sealing plug 16 is made of resin. The sealing plug 16 is preferably made of a resin material that has excellent sealing properties and moldability, resistance to the electrolyte used (electrolyte resistance), and electrical insulation properties. Specific examples include polyethylene (PE), polypropylene (PP), polyphenylene sulfide (PPS), perfluoroalkoxyalkane (PFA), perfluoroethylenepropene copolymer (FEP), and polyethylene terephthalate (PET). The resin material is preferably a thermoplastic resin. The resin material may contain conventionally known additives and fillers such as ceramic.

[0027] 3 is a vertical cross-sectional view schematically showing the vicinity of the electrolyte injection hole 15. As shown in FIG. 3, the sealing plug 16 has a sealing plug shaft 16s and a sealing plug flange 16f. In this embodiment, the sealing plug shaft 16s and the sealing plug flange 16f are molded integrally (as a single member), for example, by integral molding. Therefore, there is no clear boundary between the sealing plug shaft 16s and the sealing plug flange 16f.

[0028] The sealing plug shank 16s is attached to the electrolyte injection hole 15. As shown in FIG. 3, the outer diameter Rs of the sealing plug shank 16s is approximately the same as the diameter of the electrolyte injection hole 15. The sealing plug shank 16s extends along the electrolyte injection hole 15. In this example, the axis of the sealing plug shank 16s extends along the long side direction Y. In this example, the axis of the sealing plug shank 16s extends in a direction approximately parallel to the winding axis of the electrode body 20. It is preferable that the sealing plug shank 16s entirely covers the inner peripheral wall of the electrolyte injection hole 15. It is preferable that the thickness Ts (average length in the long side direction Y) of the sealing plug shank 16s is greater than the base thickness Ta of the sealing plate 14 (average length in the long side direction Y at a portion without irregularities). The upper end of the sealing plug shank 16s is connected to the sealing plug flange 16f.

[0029] The sealing plug shaft portion 16s is roughly divided into two regions in the direction in which the electrolyte injection hole 15 extends (axial direction, long side direction Y in FIG. 3), and has a columnar portion 161 and a hollow tubular portion 162 located more inward in the case 10 than the columnar portion 161 (left side in FIG. 3). The columnar portion 161 is a portion that is connected to the sealing plug flange portion 16f. Here, the columnar portion 161 has a cylindrical shape.

[0030] The cylindrical portion 162 is disposed at the left end of the sealing plug shaft 16s, i.e., at the end opposite to the side where the sealing plug flange 16f of the sealing plug shaft 16s is located. The cylindrical portion 162 extends along the electrolyte injection hole 15. Here, the cylindrical portion 162 has a hollow, approximately cylindrical shape. The cylindrical portion 162 has a cavity C1 extending along the long side direction Y on the radially inner side of the sealing plug shaft 16s. The thickness T2 of the cylindrical portion 162 (average length in the long side direction Y) is preferably equal to or greater than the thickness T1 of the columnar portion 161 (average length in the long side direction Y). The thickness T2 of the cylindrical portion 162 is preferably greater than the thickness Tf of the sealing plug flange 16f (average length in the long side direction Y). Here, the cylindrical portion 162 protrudes from the electrolyte injection hole 15 and extends leftward (inward inward in the case 10) beyond the left surface 14L of the sealing plate 14. It is preferable that the left end of the cylindrical portion 162 protrudes inward beyond the thickness of the case 10 (the left surface 14L of the sealing plate 14). It is preferable that the overall thickness (T1 + T2) of the sealing plug shaft portion 16s is greater than the base thickness Ta of the sealing plate 14.

[0031] The sealing plug flange 16f is formed integrally with the sealing plug shaft 16s and extends from the sealing plug shaft 16s to the outside of the case 10. More specifically, the sealing plug flange 16f extends continuously from the right end (columnar portion 161) of the sealing plug shaft 16s and protrudes from the electrolyte injection hole 15 of the sealing plate 14 to the outside of the case 10. The sealing plug flange 16f is in contact with the outer surface of the case 10 (the right surface 14R of the sealing plate 14). The outer diameter Rf of the sealing plug flange 16f is larger than the outer diameter Rs of the sealing plug shaft 16s. The outer diameter Rf of the sealing plug flange 16f is larger than the electrolyte injection hole 15. The sealing plug flange 16f covers the top of the electrolyte injection hole 15 and further extends to the periphery of the electrolyte injection hole 15 on the right surface 14R of the sealing plate 14.

[0032] As shown in FIG. 1, the sealing plug flange 16f has a gourd-like shape in plan view (two substantially circular sections connected in the vertical direction Z with a central constriction) due to the manufacturing method described below. The area of ​​the lower section (the substantially circular section located at the bottom) separated by the central constriction is larger than that of the upper section (the substantially circular section located at the top). In other words, the sealing plug flange 16f has a snowman shape. Furthermore, due to the manufacturing method described below, the sealing plug flange 16f typically has a melting mark formed by melting and solidifying the resin. The melting mark is preferably formed at least in a portion of the sealing plug flange 16f that overlaps with the electrolyte injection hole 15 in plan view.

[0033] The thickness Tf of the sealing plug flange 16f is preferably smaller than the overall thickness Ts of the sealing plug shaft 16s. Although not shown, the thickness Tf of the sealing plug flange 16f is preferably smaller than the thickness (average length in the long side direction Y) of the positive electrode terminal 30. By reducing the protruding height of the sealing plug flange 16f, it is possible to prevent the sealing plug 16 from being damaged or broken due to interference of the sealing plug flange 16f with other members.

[0034] Although not particularly limited, it is preferable that at least one of the inner peripheral wall of the electrolyte injection hole 15 of the case 10 (the portion where the sealing plug shaft portion 16s is provided) and the peripheral edge portion of the electrolyte injection hole 15 on the top surface (outer surface) 14u of the case 10 (the portion where the sealing plug flange portion 16f is provided) be roughened. This improves the adhesion between the case 10 and the sealing plug 16, and improves the sealing performance and reliability of the sealing plug 16. From the viewpoint of achieving this effect at a high level, it is more preferable that the roughening be formed continuously in the circumferential direction of the electrolyte injection hole 15.

[0035] <Method of manufacturing the electricity storage device 100> The above-described power storage device 100 can be manufactured by a manufacturing method including, for example, a preparation step (step S1), a liquid injection step (step S2), and a sealing step (step S3). The remaining manufacturing processes may be the same as conventional methods. The manufacturing method disclosed herein may further include other steps at any stage. FIG. 4(A) is a diagram equivalent to FIG. 3 at the preparation step (step S1), FIG. 4(B) is a diagram equivalent to FIG. 3 at the liquid injection step (step S2), FIG. 4(C) is a diagram equivalent to FIG. 3 at the end of the liquid injection step (step S2), and FIG. 4(D) is a diagram equivalent to FIG. 3 at the sealing step (step S3). In the drawings, the right side (the right surface 14R side) of the sealing plate 14 is outside the case 10, and the left side (the left surface 14L side) is inside the case 10.

[0036] The preparation step (step S1) is a step of preparing an assembly including a case 10 having an electrolyte injection hole 15 and a resin member 17 (see FIG. 4(A)) attached to the electrolyte injection hole 15, and an electrode body 20 disposed in the case 10. Specifically, for example, first, a sealing plate 14 having an electrolyte injection hole 15 is prepared, and the resin member 17 is attached to the electrolyte injection hole 15. In a preferred embodiment, the resin member 17 is integrated with the case 10 (e.g., the sealing plate 14) by integral molding (insert molding). This reduces the number of parts and lowers costs. Furthermore, the resin member 17 can be attached more firmly to the case 10. When the resin member 17 is integrally molded with the case 10 (e.g., the sealing plate 14), it is preferable to roughen at least one of the inner wall of the electrolyte injection hole 15 of the case 10 and the peripheral edge of the electrolyte injection hole 15 on the upper surface (outer surface) 14u of the case 10 in advance.

[0037] 5 is a perspective view schematically illustrating the resin member 17 in this step. The resin member 17 is a member that is partially melted in a sealing step (step S3) described later to form the above-described sealing plug 16 (more specifically, the sealing plug shank 16s and the sealing plug flange 16f). As shown in FIGS. 4(A) and 5, in this embodiment, the resin member 17 has a hollow shank 17s (not shown in FIG. 5) attached to the electrolyte injection hole 15, a through-hole 17h that penetrates the resin member 17 along the axis of the shank 17s, and a liquid receiving portion 17r that is integral with the shank 17s and extends from the shank 17s to the outside of the case 10 (e.g., the outside of the sealing plate 14) around at least a portion of the periphery of the through-hole 17h. By providing the liquid receiving portion 17r integrally with the shaft portion 17s, the number of components used can be reduced compared to when the liquid receiving portion 17r and the shaft portion 17s are separate components, thereby reducing costs and making it easier to prepare the resin member 17.

[0038] The stem 17s is a portion that forms the sealing plug stem 16s of the sealing plug 16 after a sealing step (step S3) described later. The stem 17s extends along the electrolyte injection hole 15 (here, in the long-side direction Y). The stem 17s preferably covers the entire inner peripheral wall of the electrolyte injection hole 15. The lower end of the stem 17s protrudes from the electrolyte injection hole 15 and extends leftward (inward of the case 10) beyond the left surface 14L of the sealing plate 14. By making the stem 17s longer than the thickness of the sealing plate 14, the electrolyte is less likely to drip from the electrolyte injection hole 15 in the injection step (step S2) described later. Furthermore, the electrolyte is prevented from flowing down the end face (left end) of the stem 17s on the case 10 side and reaching the interface with the sealing plate 14. This improves sealing performance and reliability.

[0039] The through hole 17h is a portion that may remain as a hollow portion C1 of the sealing plug 16 even after a sealing step (step S3) described later. The through hole 17h communicates between the inside and outside of the case 10. In this example, the through hole 17h is provided on the radially inner side of the shaft portion 17s. Although not particularly limited, the diameter Rh (see FIG. 4(A)) of the through hole 17h may be 1 mm or less, for example, when an electrolyte is injected using an injection nozzle 200 (see FIG. 4(B)) in a liquid injection step (step S2) described later.

[0040] The liquid receiving portion 17r is a portion that prevents the electrolyte from adhering to the case 10 in the sealing step (step S3) described below. The liquid receiving portion 17r is a portion that becomes a part (columnar portion 161) of the sealing plug shaft portion 16s of the sealing plug 16 and / or the sealing plug flange portion 16f after the sealing step (step S3). As shown in FIG. 5, the liquid receiving portion 17r has a substantially semicylindrical shape. The liquid receiving portion 17r has a substantially semicircular shape in cross section. When the resin member 17 is divided into two in the vertical direction Z, with the upper side defined as an upper region 17U and the lower region 17D, the liquid receiving portion 17r is provided only in the lower region 17D of the resin member 17. In other words, the liquid receiving portion 17r is not provided in the upper region 17U of the resin member 17.

[0041] In the lower region 17D, the liquid receiving portion 17r extends horizontally (in the long-side direction Y) from the right end of the shaft portion 17s outside the case 10. As shown in FIG. 4A, the horizontally extending length (maximum length) Lr of the liquid receiving portion 17r is preferably greater than the diameter Rh of the through-hole 17h, more preferably at least twice the diameter Rh, and even more preferably, for example, 3 to 5 times the diameter Rh. Furthermore, the length Lr of the liquid receiving portion 17r is preferably greater than the diameter Ra of the electrolyte injection hole 15, and more preferably, for example, 1.2 to 3 times the diameter Ra. Setting the length Lr of the liquid receiving portion 17r to a predetermined value or greater can increase the molten metal in the sealing step (step S3), thereby improving the sealing performance and reliability of the electrolyte injection hole 15. Setting the length Lr of the liquid receiving portion 17r to a predetermined value or less can reduce the protruding height of the sealing plug flange portion 16f in the electricity storage device 100. The length Lr of the liquid receiving portion 17r is preferably longer than the horizontal protrusion length of the positive electrode terminal 30. This makes it less likely that the positive electrode terminal 30 will be soiled with the electrolyte in the liquid injection step (step S2) described below. In one example, the length Lr of the liquid receiving portion 17r is preferably about 20 to 70 mm, and more preferably 30 to 50 mm.

[0042] In this embodiment, the resin member 17 is formed integrally with the shaft portion 17s and further includes an edge portion 17e provided on the periphery of the through-hole 17h on the outside of the case 10. The edge portion 17e is a portion that will become a part (the columnar portion 161) of the sealing plug shaft portion 16s of the sealing plug 16 and / or the sealing plug flange portion 16f after the sealing step (step S3). As shown in FIG. 5, the edge portion 17e is provided only in the upper region 17U of the resin member 17. The edge portion 17e has a substantially semicircular shape in cross section. A notch may be provided in part of the edge portion 17e. The edge portion 17e is in contact with the outer surface of the case 10 (the right surface 14R of the sealing plate 14).

[0043] In the upper region 17U, the edge 17e protrudes horizontally (in the long side direction Y) from the right end of the shaft 17s outside the case 10. As shown in FIG. 4(A), the horizontal protrusion length (maximum length) Le of the edge 17e is shorter than the length Lr of the liquid receiving portion 17r. The length Le of the edge 17e is preferably equal to or less than half the length Lr of the liquid receiving portion 17r, and more preferably, for example, 1 / 3 to 1 / 5 of the length Lr. This makes it easier to inject the electrolyte through the through-hole 17h in the liquid injection step (step S2) described below.

[0044] In this process, the electrode assembly 20 is prepared, and the positive electrode current collector 32 is attached to the positive electrode tab 22 of the electrode assembly 20, and the negative electrode current collector 42 is attached to the negative electrode tab 24. Next, two sealing plates 14, a positive electrode terminal 30, and a negative electrode terminal 40 are prepared, and the positive electrode terminal 30 and the positive electrode current collector 32 are attached to one sealing plate 14, and the negative electrode terminal 40 and the negative electrode current collector 42 are attached to the other sealing plate 14. This integrates the two sealing plates 14, the positive electrode terminal 30, the negative electrode terminal 40, and the electrode assembly 20. Next, the case body 12 is prepared, and the electrode assembly 20 integrated with the sealing plate 14 is placed in the internal space of the case body 12, and the pair of openings 12h of the case body 12 are sealed with the sealing plates 14. Sealing can be performed by welding, for example, laser welding. In this manner, an assembly is prepared. In the assembly, the resin member 17 (particularly the liquid receiving portion 17r) is preferably provided at a position that overlaps the portion of the positive electrode terminal 30 that protrudes from the case 10 in a plan view.

[0045] The liquid injection step (step S2) is a step of injecting the electrolyte into the case 10 through the electrolyte injection hole 15. In a preferred embodiment, the injection is performed using a conventionally known electrolyte injection device that includes an injection nozzle 200 (see FIG. 4(B)) for injecting the electrolyte, an electrolyte reservoir (not shown) that communicates with the injection nozzle 200, and a liquid delivery means (e.g., a pressure pump) that delivers the electrolyte from the electrolyte reservoir to the injection nozzle 200. However, in other embodiments, the injection may be performed using, for example, a dispenser or the like.

[0046] In this embodiment, as shown in FIG. 4(B), the assembly is first positioned so that the through-hole 17h is open in the horizontal direction (longer side direction Y) and the liquid receiving portion 17r of the resin member 17 is positioned below the opening of the through-hole 17h. The edge portion 17e of the resin member 17 is positioned vertically above the liquid receiving portion 17r. By providing the liquid receiving portion 17r below the through-hole 17h, even if electrolyte drips from the injection nozzle 200 due to an impact when the injection nozzle 200 is brought into contact with the through-hole 17h, the dripping electrolyte can be received by the liquid receiving portion 17r. This prevents the case 10 (especially the positive electrode terminal 30 positioned vertically below) and the surrounding floor from being soiled with electrolyte. Furthermore, providing the edge portion 17e above the through-hole 17h facilitates insertion of the injection nozzle 200 into the through-hole 17h, improving operability.

[0047] Next, as shown by the arrow in FIG. 4(B), the liquid injection nozzle 200 is inserted into the through-hole 17h, and the electrolyte is injected into the case 10. At this time, by moving the liquid injection nozzle 200 along the liquid receiving portion 17r, the liquid receiving portion 17r can serve as a guide for inserting the liquid injection nozzle 200. This allows the liquid injection nozzle 200 to be smoothly inserted even if the diameter of the through-hole 17h is small, for example, 1 mm or less. Furthermore, in this embodiment, the horizontal length of the stem portion 17s of the resin member 17 is longer than the thickness of the sealing plate 14, so that the electrolyte is prevented from flowing down the end face (left end) of the stem portion 17s on the case 10 side and reaching the interface with the sealing plate 14.

[0048] Then, after the injection is completed, the injection nozzle 200 is withdrawn from the through-hole 17h. At this time, as shown in FIG. 4(C), particularly when the through-hole 17h is open in the horizontal direction (longer side direction Y), for example, electrolyte may remain in the through-hole 17h, or electrolyte adhering to the inner wall of the injection nozzle 200 may drip from the injection nozzle 200 when the injection nozzle 200 is withdrawn. However, according to the technology disclosed herein, this electrolyte can be received by the liquid receiving portion 17r. Therefore, the electrolyte is less likely to drip onto the case 10 or the surrounding floor. This in turn prevents the vicinity of the electrolyte injection hole 15 of the case 10 from becoming soiled or discolored. This also reduces the time and effort required to clean up the soiled manufacturing line and the dripped electrolyte.

[0049] The sealing step (step S3) is a step of sealing the electrolyte injection hole 15. In this embodiment, the resin member 17 (typically, the liquid receiving portion 17r) is melted at least on the outside of the case 10 (here, the right surface 14R of the sealing plate 14). The resin member 17 flows along the right surface 14R of the sealing plate 14, flows into the through hole 17h, and is cooled and solidified. This blocks the through hole 17h, thereby forming a part (the columnar portion 161) of the sealing plug shaft portion 16s. Furthermore, the excess material that does not flow into the through hole 17h forms the sealing plug flange portion 16f. By melting the resin member 17, the electrolyte injection hole 15 can be sealed more easily than before, improving workability and productivity.

[0050] The means for melting the resin member 17 is not particularly limited, but an example is a contact-type heating means in which a heating medium is brought into direct contact with the resin member 17 on the outside of the case 10. This makes it easier to locally melt and flow the resin member 17. Examples of contact-type heat treatment means include heat pressing, ultrasonic heating, and impulse welding. However, the heat treatment means may also be a non-contact heat treatment means such as laser heating.

[0051] In a preferred embodiment, the resin member 17 is melted by heat pressing. In the heat pressing, a heated metal plate (heating medium) HP is brought into contact with the resin member 17 from above and pressed against the right surface 14R of the sealing plate 14, as shown in FIG. 4(D), for example. The temperature of the metal plate HP is preferably set to a temperature equal to or higher than the melting point of the resin material constituting the resin member 17 (e.g., melting point + 5°C or higher) so that the resin member 17 can be easily melted. At this time, the electrolyte adhering to the resin member 17 may evaporate due to the heat. The use of heat pressing makes it easier to seal the electrolyte injection hole 15, improving workability. Furthermore, it makes it easier to form a flat sealing plug flange 16f, which prevents the sealing plug 16 from being damaged or broken due to interference with other components. In this manner, the resin member 17 is molded into the sealing plug 16, sealing the electrolyte injection hole 15. Consequently, the electricity storage device 100 is hermetically sealed.

[0052] <Uses of the electricity storage device 100> The electricity storage device 100 can be used for various purposes, and can be suitably used, for example, as a power source (driving power source) for a motor mounted on a vehicle such as a passenger car, a truck, etc. The type of vehicle is not particularly limited, and examples thereof include a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), and a battery electric vehicle (BEV).

[0053] 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.

[0054] 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, comprising: a preparation step of preparing an assembly including a case having an electrolyte injection hole and a resin member attached to the electrolyte injection hole, and an electrode body arranged in the case; a filling step of filling an electrolyte into the case from the electrolyte injection hole; and a sealing step of sealing the electrolyte injection hole after the filling step, wherein the resin member has a hollow shaft attached to the electrolyte injection hole, a through hole penetrating the resin member along the axis of the shaft, and a liquid receiving portion that is formed integrally with the shaft and extends from the shaft to outside the case at least on a periphery of the through hole; Item 2: The manufacturing method according to Item 1, wherein in the liquid injection step, a liquid injection nozzle is inserted into the through-hole to inject the electrolyte, and after the liquid injection, the liquid injection nozzle is pulled out from the through-hole. Item 3: The manufacturing method according to Item 1 or 2, wherein the liquid receiving portion of the resin member has a substantially semicircular shape in cross section. Item 4: The manufacturing method according to any one of Items 1 to 3, wherein the resin member is formed integrally with the shaft portion and further has an edge portion provided on the periphery of the through hole on the outside of the case, and during the liquid pouring step, the edge portion is positioned vertically above the liquid receiving portion. Item 5: The manufacturing method according to any one of Items 1 to 4, wherein the length of the liquid receiving portion of the resin member extending in the horizontal direction is greater than the diameter of the through-hole. Item 6: The production method according to any one of items 1 to 5. Clause 7: An electricity storage device comprising: a case having an electrolyte injection hole; an electrode assembly and an electrolyte disposed in the case; and a sealing plug that closes the electrolyte injection hole of the case, wherein the electrolyte injection hole is provided on a side surface of the case and extends horizontally; the sealing plug is made of resin and has a sealing plug stem attached to the electrolyte injection hole; and a sealing plug flange that is formed integrally with the sealing plug stem and extends radially outside the case, wherein the sealing plug flange has a gourd shape in which two substantially circular portions are connected in a vertical direction in a horizontal plan view; and the area of ​​the substantially circular portion located at the lower side in the vertical direction is larger than the area of ​​the substantially circular portion located at the upper side. Item 8: The electricity storage device according to item 7, wherein a hollow cylindrical portion is provided at the end of the sealing plug shaft portion opposite to the end where the sealing plug flange portion is located. Item 9: The electricity storage device according to item 8, wherein the cylindrical portion protrudes inward beyond a thickness of the case. Item 10: The electricity storage device according to any one of Items 7 to 9, wherein the sealing plug flange has a melting mark. Item 11: The electricity storage device according to any one of items 7 to 10, wherein the electrolyte injection hole 15 is provided vertically above the first electrode terminal. [Explanation of symbols]

[0055] 10 cases 12 Case body 14 Sealing plate 15 Electrolyte injection hole 16 Sealing plug 16s Sealing plug shaft 161 Columnar part 162 Cylindrical part 16f Sealing plug flange 20 Electrode body 100 Energy storage device 17 Resin parts 17s shaft part 17h through hole 17r Liquid receiving part 17e Edge

Claims

1. a preparation step of preparing an assembly including a case having an electrolyte injection hole and a resin member attached to the electrolyte injection hole, and an electrode body disposed in the case; a liquid injection step of injecting an electrolyte into the case through the electrolyte injection hole; a sealing step of sealing the electrolyte injection hole after the injection step; Including, The resin member is a hollow shaft portion attached to the electrolyte injection hole; a through hole that penetrates the resin member along the axis of the shaft portion; a liquid receiving portion that is integral with the shaft portion and extends from the shaft portion to the outside of the case at least in part of the periphery of the through hole, In the liquid injection step, the assembly is disposed so that the liquid receiving portion of the resin member is located below the opening of the through hole, and the electrolyte is injected; In the sealing step, the resin member is melted at least on the outside of the case to close the through hole. A method for manufacturing an electricity storage device.

2. In the liquid injection step, a liquid injection nozzle is inserted into the through hole to inject the electrolyte, and after the liquid injection, the liquid injection nozzle is pulled out from the through hole. The method of claim 1.

3. The liquid receiving portion of the resin member has a substantially semicircular shape in cross section. The method according to claim 1 or 2.

4. the resin member is integral with the shaft portion and further has an edge portion provided on the periphery of the through hole on the outside of the case, In the liquid pouring step, the edge portion is positioned vertically above the liquid receiving portion. The method according to claim 1 or 2.

5. a horizontally extending length of the liquid receiving portion of the resin member is greater than a diameter of the through hole; The method according to claim 1 or 2.

6. the electrolyte injection hole is provided on a side surface of the case, In the liquid injection step, the electrolyte is injected with the through-hole opened in a horizontal direction. The method according to claim 1 or 2.

7. a case having an electrolyte injection hole, an electrode assembly and an electrolyte disposed in the case, and a sealing plug that closes the electrolyte injection hole of the case; the electrolyte injection hole is provided on a side surface of the case and extends horizontally; The sealing plug is made of resin, and a sealing plug shaft portion attached to the electrolyte injection hole; a sealing plug flange portion that is integral with the sealing plug shaft portion and that extends radially outward from the case, the sealing plug flange has a gourd-like shape in a horizontal plan view, with two generally circular portions connected in the up-down direction, and the area of ​​the generally circular portion located on the lower side is larger than the area of ​​the generally circular portion located on the upper side; Energy storage device.

8. a hollow cylindrical portion is provided at an end of the sealing plug shaft opposite to the end where the sealing plug flange is located; The electricity storage device according to claim 7 .

9. The cylindrical portion protrudes inward beyond the thickness of the case. The electricity storage device according to claim 8 .

10. The sealing plug flange has a melting mark. The electricity storage device according to claim 8 or 9.

11. Further comprising a first electrode terminal and a second electrode terminal, The electrolyte injection hole 15 is provided vertically above the first electrode terminal. The electricity storage device according to claim 8 or 9.

Images