Electricity storage device and method for manufacturing same

Abstract

The invention relates to a power storage device and a manufacturing method thereof, and provides an easier manufacturing method of the power storage device. The manufacturing method disclosed herein includes: a preparation step of preparing an assembly including a housing in which a resin member is attached to an electrolyte injection hole; and a sealing step for sealing the electrolyte injection hole after injection of the electrolyte, the resin member having a hollow shaft portion, a through-hole, and an excess portion protruding on the outer side of the housing at the periphery of the through-hole, and in the sealing step, the through-hole is sealed by melting at least the excess portion.

Description

Technical Field

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

[0002] In the past, it is known that there is a kind of power storage device, which comprises: a shell having an electrolyte injection hole; an electrode body and an electrolyte, which are arranged in the shell; and a sealing plug, which seals the electrolyte injection hole. As related prior art documents, Japanese Patent Publication No. 2017-195093, Japanese Patent Publication No. 2015-111527, and Japanese Patent Publication No. 2015-536033 can be cited. For example, Japanese Patent Publication No. 2017-195093 discloses a power storage device, which has a main body (first component) that is provided with an electrolyte injection hole and integrated with the shell, and a sealing plug (second component) that blocks the electrolyte injection hole. Japanese Patent Publication No. 2017-195093 states that after the electrolyte is injected from the electrolyte injection hole of the main body, the sealing plug is inserted into the electrolyte injection hole, and the main body and the sealing plug are joined by laser welding.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-195093

[0004] Patent Document 2: Japanese Patent Application Laid-Open No. 2015-111527

[0005] Patent Document 3: Japanese Patent Application No. 2015-536033

[0006] From the viewpoints of improving workability and reducing costs, a simpler production method is desired. Summary of the Invention

[0007] According to the present invention, a method for manufacturing an electrical storage device is provided, the method comprising: a preparation step of preparing an assembly comprising a housing having an electrolyte injection hole and a resin member mounted in the electrolyte injection hole, and an electrode body disposed within the housing; an injection step of injecting electrolyte into the housing through the electrolyte injection hole; and a sealing step of sealing the electrolyte injection hole after the injection step. The resin member comprises: a hollow shaft mounted in the electrolyte injection hole; a through hole extending through the resin member along the axis of the shaft; and a slug portion integrally formed with the shaft portion and protruding from the outside of the housing at the periphery of the through hole. In the sealing step, the through hole is sealed by melting at least the slug portion.

[0008] In the present invention, the electrolyte injection hole is sealed by melting a portion (at least the remaining portion) of a resin component mounted on the injection hole. This makes it easy to seal the electrolyte injection hole. Furthermore, since a separate sealing plug (second component) is not required, the number of components can be reduced compared to conventional techniques. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a perspective view schematically showing an electric storage device 100 according to one embodiment.

[0010] Figure 2 It is along Figure 1 Schematic longitudinal cross-sectional view along line II-II.

[0011] Figure 3 It is a longitudinal cross-sectional view schematically showing the vicinity of the electrolyte injection hole.

[0012] Figure 4 (A) Figure 4 (B) is an illustration of the manufacturing process. Figure 4 (A) is the equivalent of the preparation process Figure 3 The picture, Figure 4 (B) is the equivalent of the sealing process Figure 3 Picture.

[0013] Figure 5 This is the equivalent of the modification involved in Figure 1 Picture.

[0014] Description of Reference Numerals

[0015] 10, 110…housing; 12, 112…housing body; 14, 114…sealing plate; 15, 115…electrolyte injection hole; 16, 116…sealing plug; 16s…sealing plug shaft; 161…columnar portion; 162…cylindrical portion; 16f…sealing plug flange; 20…electrode body; 100…electrical storage device; 17…resin component; 17s…shaft portion; 17h…through hole; 17e…surplus part; 17p…projection. DETAILED DESCRIPTION

[0016] Hereinafter, preferred embodiments of the technology disclosed herein will be described with appropriate reference to the accompanying drawings. Matters required for the implementation of the technology disclosed herein (for example, the general structure and manufacturing process of the storage device that does not characterize the technology disclosed herein) other than matters specifically mentioned in this specification can be grasped as design matters based on the existing technology in this field by those skilled in the art. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in this field. In addition, the expression "A to B" indicating the range in this specification includes the meaning of "preferably greater than A" and "preferably less than B" together with the meaning of A or more and B or less.

[0017] <Electrical Storage Device 100>

[0018] Figure 1 It is a perspective view of the power storage device 100 . Figure 2 It is along Figure 1 Schematic longitudinal cross-sectional view along line II-II. In the following description, components / parts that perform the same function are sometimes denoted by the same reference numerals, and repeated descriptions are omitted or simplified. Furthermore, the reference numerals F, Rr, L, R, U, and D in the drawings represent front, rear, left, right, top, and bottom, and the reference numerals X, Y, and Z in the drawings represent the short side direction, the long side direction orthogonal to the short side direction, and the up and down direction of the electrical storage device 100, respectively. The up and down direction Z is typically the same as the vertical direction. However, these directions are merely for ease of description and do not in any way limit the arrangement of the electrical storage device 100.

[0019] like Figure 2 As shown, the electrical storage device 100 includes a housing 10, an electrode body 20, an electrolyte (not shown), a positive terminal 30, a negative terminal 40, and a sealing plug 16. Here, the electrical storage device 100 is a non-aqueous electrolyte secondary battery. Preferably, the electrical storage device 100 is a lithium-ion secondary battery. In this specification, the term "electrical storage device" refers to any device that can be repeatedly charged and discharged, and is a concept that includes secondary batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries, as well as capacitors such as lithium-ion capacitors and electric double-layer capacitors.

[0020] The outer shell 10 is a shell that houses the electrode body 20 and the electrolyte. Figure 1 As shown, here, the housing 10 has a flat, bottomed cubic (square) shape. The material of the housing 10 can be the same as that used in the past and is not particularly limited. Preferably, the housing 10 is made of metal, for example, more preferably aluminum, aluminum alloy, iron, iron alloy, etc.

[0021] like Figure 2As shown, in this embodiment, the housing 10 includes a housing body 12 having a bottomed square (box-shaped) shape and an opening 12h on one side (here, the upper side); and a sealing plate (lid) 14 that seals the opening 12h of the housing body 12. The housing 10 is integrated by joining (e.g., welding) the sealing plate 14 to the periphery of the opening 12h of the housing body 12. The housing 10 is hermetically sealed (enclosed).

[0022] like Figure 1 As shown, the housing body 12 includes a bottom surface 12a, a pair of long side surfaces 12b extending from the bottom surface 12a and opposing each other, and a pair of short side surfaces 12c extending from the bottom surface 12a and opposing each other. The bottom surface 12a is generally rectangular with a pair of short sides and a pair of long sides. The bottom surface 12a is opposite the opening 12h. The long side surfaces 12b extend from the pair of long sides of the bottom surface 12a, respectively. The short side surfaces 12c extend from the pair of short sides of the bottom surface 12a, respectively. When viewed from above, the area of ​​the long side surfaces 12b is larger than the area of ​​the short side surfaces 12c.

[0023] In this specification, "substantially rectangular" is a term that includes not only a complete rectangular shape (rectangle), but also a shape in which the corners connecting the long side and the short side of the rectangle are arc-shaped, a shape with a cutout at the corner, etc.

[0024] The sealing plate 14 is a plate-shaped component that blocks the opening 12h of the housing body 12. Here, the sealing plate 14 constitutes the upper surface of the housing 10. The sealing plate 14 is opposite to the bottom surface 12a of the housing body 12. When viewed from above, the sealing plate 14 is roughly rectangular. Figure 2 As shown, the sealing plate 14 is provided with an electrolyte injection hole 15 and two terminal lead-out holes 18 and 19. The terminal lead-out holes 18 and 19 penetrate the sealing plate 14 in the vertical direction Z. The terminal lead-out holes 18 and 19 each have an inner diameter large enough to allow the positive terminal 30 and the negative terminal 40 to pass through before being attached to the sealing plate 14 (before caulking).

[0025] The electrolyte injection hole 15 is used to inject the electrolyte after the sealing plate 14 is assembled to the shell body 12. The electrolyte injection hole 15 is a through hole that penetrates the sealing plate 14 in the up and down direction Z. Here, when viewed from above, the electrolyte injection hole 15 is roughly circular. The electrolyte injection hole 15 is sealed by the sealing plug 16 after the electrolyte is injected. The sealing plug 16 will be described later. In addition, in the present embodiment, the electrolyte injection hole 15 is provided in the sealing plate 14, but in other embodiments, the electrolyte injection hole 15 may also be provided in the shell body 12 (for example, any one of the bottom surface 12a, the long side 12b and the short side 12c).

[0026] In this specification, "substantially circular" is not limited to a perfect circle (a true circle), but is a term that includes circular shapes with partially different curvatures of arcs (such as ellipses) and shapes derived from a perfect circle or a circle.

[0027] The positive electrode terminal 30 is arranged at one end portion of the sealing plate 14 in the longitudinal direction Y ( Figure 1 、 Figure 2 The left end of Figure 2 As shown, the positive terminal 30 is inserted through the terminal lead-out hole 18 and extends from the inside to the outside of the sealing plate 14. Here, the positive terminal 30 is caulked to the peripheral portion of the sealing plate 14 surrounding the terminal lead-out hole 18 by caulking. Figure 2 A caulking portion 30c is formed at the lower end of the positive electrode terminal 30. The positive electrode terminal 30 is preferably made of metal, more preferably aluminum or an aluminum alloy. Within the housing 10, the positive electrode terminal 30 is electrically connected to the positive electrode tab 23 of the electrode body 20 via the positive electrode current collector 50. The positive electrode terminal 30 is insulated from the sealing plate 14 by an internal insulating member 80 and a gasket 90.

[0028] The negative electrode terminal 40 is arranged at the other end portion of the sealing plate 14 in the longitudinal direction Y ( Figure 1 、 Figure 2 The right end of Figure 2 As shown, the negative terminal 40 is inserted through the terminal lead-out hole 19 and extends from the inside to the outside of the sealing plate 14. Here, the negative terminal 40 is caulked to the peripheral portion of the sealing plate 14 surrounding the terminal lead-out hole 19 by caulking. Figure 2 A caulking portion 40c is formed at the lower end of the negative electrode terminal 40. The negative electrode terminal 40 is preferably made of metal, more preferably copper or a copper alloy. Within the housing 10, the negative electrode terminal 40 is electrically connected to the negative electrode tab 25 of the electrode assembly 20 via the negative electrode current collector 60. The negative electrode terminal 40 is insulated from the sealing plate 14 by an internal insulating member 80 and a gasket 90.

[0029] The electrode body 20 is housed inside the outer shell 10. The structure and method of the electrode body 20 can be the same as before and are not particularly limited. The number of electrode bodies 20 housed inside one outer shell 10 is not particularly limited and can be one or more than two (plural). Although not shown in the figure, the electrode body 20 typically has a positive electrode and a negative electrode. The positive electrode typically has a positive electrode collector and a positive electrode active material layer fixed to the positive electrode collector. The negative electrode typically has a negative electrode collector and a negative electrode active material layer fixed to the negative electrode collector. The electrode body 20 can also be housed inside the outer shell 10 in a state covered by an insulating sheet (electrode body holder) made of resin.

[0030] Here, the electrode body 20 is a wound electrode body in which a strip-shaped positive electrode and a strip-shaped negative electrode are stacked with a strip-shaped separator and wound in the longitudinal direction with a winding axis as the center. However, in other embodiments, the electrode body 20 may also be a stacked electrode body in which a plurality of square (typically rectangular) positive electrodes and a plurality of square (typically rectangular) negative electrodes are stacked in an insulated state. In addition, in this embodiment, the electrode body 20 is arranged inside the housing 10 in an orientation in which the winding axis is substantially parallel to the longitudinal direction Y. However, in other embodiments, the electrode body 20 may also be arranged inside the housing 10 in an orientation in which the winding axis is substantially parallel to the up-down direction Z, for example.

[0031] like Figure 2 As shown, a positive electrode tab 23 is provided on the positive electrode of the electrode body 20. Here, the positive electrode tab 23 is a part of the positive electrode current collector. Here, the positive electrode tab 23 is convex and extends from the electrode body 20 toward one side in the longitudinal direction Y ( Figure 2 Here, the positive electrode tab 23 is electrically connected to the positive electrode terminal 30 via the positive electrode current collecting portion 50. In addition, a negative electrode tab 25 is provided at the negative electrode of the electrode body 20. Here, the negative electrode tab 25 is a part of the negative electrode current collector. Here, the negative electrode tab 25 is convex and extends from the electrode body 20 toward the other side ( Figure 2 Here, the negative electrode tab 25 is electrically connected to the negative electrode terminal 40 via the negative electrode current collecting portion 60.

[0032] The electrolyte can be the same as in the past 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 can also be an aqueous electrolyte containing an aqueous solvent. For example, it is preferred that the non-aqueous solvent contains carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. It is preferred that the non-aqueous solvent contains carbonates. It is particularly preferred that it contains cyclic carbonates and chain carbonates. The supporting salt is, for example, a fluorine-containing lithium salt such as lithium hexafluorophosphate (LiPF6). The electrolyte may further contain additives as needed.

[0033] The sealing plug 16 is a component that is installed on the electrolyte injection hole 15 of the outer shell 10 to block the electrolyte injection hole 15. Here, the sealing plug 16 is installed on the sealing plate 14. The details will be described later in the manufacturing method, but in this embodiment, the sealing plug 16 is installed on the outer shell 10 (here, the sealing plate 14) by integral molding. However, in other embodiments, the sealing plug 16 can be joined to the outer shell 10 by friction stir welding, etc., or it can be bonded to the outer shell 10 via an adhesive layer (adhesive, etc.).

[0034] The sealing plug 16 is made of resin. Preferably, the sealing plug 16 is made of a resin material having excellent sealing and moldability, and having resistance to the electrolyte used (electrolyte resistance) and electrical insulation. Specific examples include polyethylene (PE), polypropylene (PP), polyphenylene sulfide (PPS), perfluoroalkoxyalkane (PFA), perfluoroethylene propylene copolymer (FEP), polyethylene terephthalate (PET), etc. The resin material is preferably a thermoplastic resin. The resin material may also contain conventionally known additives, ceramics, and other fillers.

[0035] Figure 3 1 is a longitudinal sectional view schematically showing the vicinity of the electrolyte injection hole 15. Figure 3 As shown, the sealing plug 16 includes a sealing plug shaft portion 16s and a sealing plug flange portion 16f. In this embodiment, the sealing plug shaft portion 16s and the sealing plug flange portion 16f are integrally molded (as a single component), for example, by integral molding. Therefore, there is no clear boundary between the sealing plug shaft portion 16s and the sealing plug flange portion 16f.

[0036] The sealing plug shaft 16s is mounted on the electrolyte injection hole 15. Figure 3 As shown, the outer diameter Rs of the sealing plug shaft portion 16s is substantially the same as the diameter of the electrolyte injection hole 15. The sealing plug shaft portion 16s extends along the electrolyte injection hole 15. Here, the axis of the sealing plug shaft portion 16s extends along the up-down direction Z. Preferably, the sealing plug shaft portion 16s completely covers the inner circumferential wall of the electrolyte injection hole 15. Preferably, the thickness (average length in the up-down direction Z) Ts of the sealing plug shaft portion 16s is greater than the base thickness (average length in the up-down direction Z at a portion without concave and convex parts) Ta of the sealing plate 14. The upper end portion of the sealing plug shaft portion 16s is connected to the sealing plug flange portion 16f.

[0037] The sealing plug shaft portion 16s extends in the direction (axial direction, Figure 3 The vertical direction Z) is roughly divided into two areas, including a columnar portion 161 and an inner side of the housing 10 ( Figure 3 The hollow cylindrical portion 162 is located at the lower side of the sealing plug. The columnar portion 161 is connected to the sealing plug flange portion 16f. Here, the columnar portion 161 is a substantially cylindrical shape.

[0038] The cylindrical portion 162 is arranged at the lower end of the sealing plug shaft portion 16s, that is, the end of the sealing plug shaft portion 16s on the opposite side to the side where the sealing plug flange portion 16f is located. The cylindrical portion 162 extends along the electrolyte injection hole 15. Here, the cylindrical portion 162 is a hollow, roughly cylindrical shape. The cylindrical portion 162 has a hollow portion C1 extending along the up-down direction Z on the radial inner peripheral side of the sealing plug shaft portion 16s. Preferably, the thickness T2 of the cylindrical portion 162 is the same as or greater than the thickness T1 of the columnar portion 161 (the average length in the up-down direction Z). Preferably, the thickness T2 of the cylindrical portion 162 is greater than the thickness Tf of the sealing plug flange portion 16f (the average length in the up-down direction Z). Here, the cylindrical portion 162 extends from the electrolyte injection hole 15 and extends downward (inside the housing 10) beyond the lower surface 14d of the sealing plate 14. The lower end of the cylindrical portion 162 preferably protrudes inwardly beyond the thickness of the housing 10 (the lower surface 14 d of the sealing plate 14 ). The overall thickness ( T1 + T2 ) of the sealing plug shaft 16 s is preferably greater than the base thickness Ta of the sealing plate 14 .

[0039] The sealing plug flange portion 16f is provided as a whole with the sealing plug shaft portion 16s, and extends from the sealing plug shaft portion 16s to the outside of the housing 10. In detail, the sealing plug flange portion 16f extends continuously from the upper end portion (columnar portion 161) of the sealing plug shaft portion 16s, and protrudes from the electrolyte injection hole 15 of the sealing plate 14 to the outside of the housing 10. The sealing plug flange portion 16f is in contact with the outer surface of the housing 10 (the upper surface 14u of the sealing plate 14). The outer diameter Rf of the sealing plug flange portion 16f is greater than the outer diameter Rs of the sealing plug shaft portion 16s. The outer diameter Rf of the sealing plug flange portion 16f is greater than the electrolyte injection hole 15. The sealing plug flange portion 16f covers the top of the electrolyte injection hole 15 and extends to the periphery of the electrolyte injection hole 15 on the upper surface 14u of the sealing plate 14. Preferably, the sealing plug flange portion 16f is substantially circular when viewed from above. The sealing plug flange portion 16f has a melt mark, which is caused by the manufacturing method described later, typically by the resin melting and solidifying. Preferably, the melt mark is formed in the portion of the sealing plug flange portion 16f that overlaps with the electrolyte injection hole 15 when viewed from above (here, directly above the electrolyte injection hole 15).

[0040] The thickness Tf of the sealing plug flange portion 16f is preferably less than the overall thickness Ts of the sealing plug shaft portion 16s. Although not shown in the figure, the thickness Tf of the sealing plug flange portion 16f is preferably less than the thickness (average length in the vertical direction Z) of the positive electrode terminal 30 and / or the negative electrode terminal 40. By reducing the protruding height of the sealing plug flange portion 16f, it is possible to prevent the sealing plug flange portion 16f from interfering with other components and thereby damaging or breaking the sealing plug 16.

[0041] While not particularly limited, it is preferred that at least one of the inner circumferential wall of the electrolyte injection hole 15 of the housing 10 (where the sealing plug shaft portion 16s is provided) and the peripheral edge of the electrolyte injection hole 15 on the upper surface (outer surface) 14u of the housing 10 (where the sealing plug flange portion 16f is provided) be roughened. This improves the adhesion between the housing 10 and the sealing plug 16, thereby enhancing the sealing performance and reliability of the sealing plug 16. To maximize this effect, it is more preferred that the roughening be performed continuously along the circumference of the electrolyte injection hole 15.

[0042] <Method of Manufacturing Electricity Storage Device 100>

[0043] The above-described electrical storage device 100 can be manufactured, for example, using a manufacturing method that includes a preparation step (step S1), a liquid injection step (step S2), and a sealing step (step S3). The remaining manufacturing steps can be the same as those in the prior art. Furthermore, the manufacturing method disclosed herein may include other steps at any stage. Figure 4 (A) is the equivalent of the preparation process (step S1) Figure 3 The picture, Figure 4 (B) is the equivalent of the sealing process (step S3) Figure 3 In the figure, the upper side of the sealing plate 14 (the upper surface 14u side) is outside the housing 10, and the lower side of the sealing plate 14 (the lower surface 14d side) is inside the housing 10.

[0044] The preparation process (step S1) is a process for preparing an assembly, wherein the assembly comprises: a housing 10 having an electrolyte injection hole 15, and a resin member 17 (see FIG. 1 ) mounted in the electrolyte injection hole 15. Figure 4 (A)); and the electrode body 20, are arranged in the outer shell 10. Specifically, for example, a sealing plate 14 having an electrolyte injection hole 15 is first prepared, and a resin component 17 is installed in the electrolyte injection hole 15. In a preferred embodiment, the resin component 17 is integrated with the outer shell 10 (for example, the sealing plate 14) by integral molding (insert molding). Thereby, the number of components can be reduced and low cost can be achieved. In addition, the resin component 17 can be more firmly mounted on the outer shell 10. Among them, when the resin component 17 is integrally molded with the outer shell 10 (for example, the sealing plate 14), it is preferred to pre-roughen at least one of the inner peripheral wall of the electrolyte injection hole 15 of the outer shell 10 and the peripheral portion of the electrolyte injection hole 15 in the upper surface (outer surface) 14u of the outer shell 10.

[0045] The resin member 17 is a member for forming the above-mentioned sealing plug 16 (specifically, the sealing plug shaft portion 16s and the sealing plug flange portion 16f). Figure 4As shown in FIG. 1A , in this embodiment, resin component 17 includes: a hollow shaft portion 17s mounted in electrolyte injection port 15; a through hole 17h extending through resin component 17 along the axis of shaft portion 17s; and a slug portion 17e integrally formed with shaft portion 17s and extending toward the periphery of through hole 17h on the outside of housing 10 (here, on the upper surface 14u side of sealing plate 14). By integrating slug portion 17e with shaft portion 17s, the number of components used can be reduced compared to a case where slug portion 17e and shaft portion 17s are separate components, resulting in lower costs. Furthermore, resin component 17 can be prepared more simply.

[0046] The shaft portion 17s is the portion of the sealing plug shaft portion 16s that forms the sealing plug 16 via the sealing process (step S3) described later. The shaft portion 17s extends along the electrolyte injection hole 15 (here, along the up-down direction Z). Preferably, the shaft portion 17s completely covers the inner circumferential wall of the electrolyte injection hole 15. The lower end portion of the shaft portion 17s extends from the electrolyte injection hole 15 and extends downward (inside the outer shell 10) than the lower surface 14d of the sealing plate 14. By making the shaft portion 17s longer than the thickness of the sealing plate 14, the electrolyte is not easily drooped from the electrolyte injection hole 15 in the injection process (step S2) described later. In addition, it is possible to prevent the electrolyte from entering the interface with the sealing plate 14 along the end surface (lower end) of the shaft portion 17s on the outer shell 10 side. Thus, the sealing performance and reliability can be improved.

[0047] Through-hole 17h is a portion that remains as the cavity C1 of sealing plug 16 after the sealing step (step S3) described later. Through-hole 17h is not closed by excess material 17e and connects the inside and outside of housing 10. Here, through-hole 17h is provided on the radially inner circumference of shaft portion 17s. Although not particularly limited, for example, when an injection nozzle is used to inject electrolyte in the injection step (step S2) described later, the diameter of through-hole 17h can be 1 mm or less.

[0048] The excess material portion 17e is a predetermined portion (predetermined melting portion) to be melted in the sealing process (step S3) described later. The excess material portion 17e is a portion of the sealing plug shaft portion 16s (columnar portion 161) and the sealing plug flange portion 16f of the sealing plug 16 formed through the sealing process (step S3). The excess material portion 17e (along the circumference of the through hole 17h) is set to surround the through hole 17h when viewed from above. Although omitted in the figure, it is preferred that the excess material portion 17e is annular when viewed from above. Thereby, it is easy to ensure the melting portion in the sealing process (step S3) described later, thereby making it easy to seal the electrolyte injection hole 15. A cutout may also be provided in a part of the annular excess material portion 17e. The outer diameter R0 of the excess material portion 17e is typically larger than the outer diameter of the shaft portion 17s. Here, the outer diameter R0 of the excess material portion 17e is larger than the electrolyte injection hole 15. Therefore, here too, the excess material portion 17 e extends toward the periphery of the electrolyte injection hole 15 .

[0049] The thickness (maximum length in the vertical direction Z) T0 of the excess material portion 17e is typically greater than the thickness Tf of the sealing plug flange portion 16f of the electrical storage device 100 (see Figure 3 Although it may vary depending on the size of the through hole 17h, the thickness T0 of the excess material portion 17e is preferably equal to or smaller than the base thickness Ta of the sealing plate 14. This can reduce the protruding height of the sealing plug flange portion 16f in the electrical storage device 100.

[0050] It is preferred that the excess material portion 17e (along the circumference of the through hole 17h) is set to surround the through hole 17h when viewed from above, and has a protrusion 17p that protrudes in a direction away from the housing 10. As a result, the melting portion in the sealing process (step S3) can be increased, and the sealing and reliability of the electrolyte injection hole 15 can be improved. Although omitted in the figure, it is preferred that the protrusion 17p is annular when viewed from above. A cutout can also be provided in a part of the annular protrusion 17p. As shown in FIG. Figure 4 As shown in (A), the protrusion 17p preferably has an inclined surface IP that slopes toward the through-hole 17h (radially inner side). This facilitates the flow of the molten portion toward the through-hole 17h during the sealing step (step S3). The upper end of the protrusion 17p preferably coincides with the outer edge of the electrolyte injection hole 15 or is radially inward of the outer edge when viewed from above.

[0051] In this process, the electrode body 20 is prepared next, the positive electrode collector 50 is mounted on the positive electrode tab 23 of the electrode body 20, and the negative electrode collector 60 is mounted on the negative electrode tab 25. Next, a sealing plate 14, a positive electrode terminal 30, and a negative electrode terminal 40 are prepared to which a resin component 17 is mounted, and the positive electrode terminal 30, the negative electrode terminal 40, the positive electrode collector 50, and the negative electrode collector 60 are mounted on the sealing plate 14. Thus, the sealing plate 14, the positive electrode terminal 30, the negative electrode terminal 40, and the electrode body 20 are integrated. Next, the outer shell body 12 is prepared, the electrode body 20 integrated with the sealing plate 14 is accommodated in the internal space of the outer shell body 12, and the opening 12h of the outer shell body 12 is sealed with the sealing plate 14. Sealing can be performed, for example, by welding such as laser welding. Prepare the assembly as described above.

[0052] The injection process (step S2) is a process of injecting electrolyte into the housing 10 from the electrolyte injection hole 15. In a preferred embodiment, a conventionally known electrolyte injection device (not shown) is used for injection, and the conventionally known electrolyte injection device includes an injection nozzle for injecting electrolyte, an electrolyte storage portion connected to the injection nozzle, and a liquid feeding means (such as a pressure pump) for delivering the electrolyte from the electrolyte storage portion to the injection nozzle. In this case, the injection nozzle is inserted into the through hole 17h to inject the electrolyte, and the injection nozzle is pulled out from the through hole 17h after the injection. Thus, even if the diameter of the through hole 17h is as small as less than 1 mm, for example, the electrolyte can be smoothly injected. However, in other embodiments, for example, a dispenser or the like can also be used for injection. In addition, in this embodiment, since the horizontal length of the shaft portion 17s of the resin member 17 is longer than the thickness of the sealing plate 14, the electrolyte can be prevented from entering the interface with the sealing plate 14 along the end surface (left end) of the shaft portion 17s on the housing 10 side.

[0053] The sealing process (step S3) is a process for sealing the electrolyte injection hole 15. In this embodiment, the excess material portion 17e is melted at least on the outside of the housing 10 (here, the upper surface 14u of the sealing plate 14). The excess material portion 17e flows along the upper surface 14u of the sealing plate 14 and flows into the through hole 17h, is cooled and solidified. As a result, the through hole 17h is blocked, and a part of the sealing plug shaft portion 16s (columnar portion 161) is formed. In addition, the sealing plug flange portion 16f is formed by the excess material that does not flow into the through hole 17h. By melting the excess material portion 17e, the electrolyte injection hole 15 can be sealed more easily than before, which can improve workability and productivity.

[0054] The method for melting the excess material portion 17e is not particularly limited. However, as an example, a contact heating method can be used, in which a heating medium is brought into direct contact with the excess material portion 17e outside the housing 10. This facilitates partial melting and flow of the excess material portion 17e. Examples of contact heat treatment methods include hot stamping, ultrasonic heating, and pulse welding. However, non-contact heat treatment methods such as laser heating may also be used.

[0055] In a preferred embodiment, the excess material portion 17e is melted by hot stamping. Figure 4 As shown in (B), the heated metal plate (heating medium) HP is brought into contact with the residual material portion 17e from above and pressed against the upper surface 14u of the sealing plate 14. The temperature of the metal plate HP is preferably a temperature above the melting point of the resin material constituting the residual material portion 17e (for example, above the melting point + 5°C) so that the residual material portion 17e can be easily melted. By adopting hot stamping, the electrolyte injection hole 15 can be sealed more easily, which can improve workability. In addition, it is easy to form the sealing plug flange portion 16f with a flat upper surface, which can prevent the sealing plug flange portion 16f from interfering with other components and damaging or breaking the sealing plug 16. As described above, the resin component 17 is formed into the sealing plug 16, and the electrolyte injection hole 15 is sealed. Furthermore, the power storage device 100 is sealed.

[0056] <Application of the Electricity Storage Device 100>

[0057] The power storage device 100 can be used for various purposes, and can be preferably used as a power source (driving power source) for motors installed in vehicles such as passenger cars and trucks. The type of vehicle is not particularly limited, and examples thereof include plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs).

[0058] The preferred embodiment of the present invention has been described above, but the above embodiment is only an example. In addition, the present invention can also be implemented in various ways. The present invention can be implemented based on the contents disclosed in this specification and the technical common sense in the field. The technology described in the technical solution includes various modifications and changes to the above-mentioned embodiment. For example, part of the above-mentioned embodiment can be replaced by other modifications, and other modifications can be added to the above-mentioned embodiment. In addition, as long as it is not stated that it is necessary for its technical features, it can also be appropriately deleted.

[0059] For example, in the above-described embodiment, the case 10 includes a bottomed square (box-shaped) case body 12 having an opening 12h on one side, and a single sealing plate 14 that seals the opening 12h on one side of the case body 12. Furthermore, the positive electrode terminal 30, the negative electrode terminal 40, and the electrolyte injection port 15 are provided on the single sealing plate 14. However, this is not limiting.

[0060] Figure 5 This is the equivalent of the modification involved in Figure 1 Picture. Figure 5 The illustrated electrical storage device 200 may be identical to the electrical storage device 100, except that it includes a housing 110, a positive terminal 130, and a negative terminal 140. The housing 110 includes a rectangular cylindrical housing body 112 having a pair of openings at both ends in the longitudinal direction Y, and two sealing plates 114 that seal the pair of openings in the housing body 112. The housing body 112 includes a generally rectangular bottom surface 112a having a pair of short sides and a pair of long sides; a pair of long side surfaces 112b extending from the pair of long sides of the bottom surface 112a and opposing each other; and a top surface 112c opposing the bottom surface 112a. For example, the housing body 112 is formed by bending a metal plate into a rectangular cylindrical shape and then joining the seams (e.g., by welding). The sealing plates 114 are plate-shaped components.

[0061] In this modification, the positive electrode terminal 130 is provided on the first sealing plate 114 ( Figure 5 The negative electrode terminal 140 is provided on the second sealing plate 114 ( Figure 5 The electrolyte injection hole 115 is provided on the first sealing plate 114 along with the positive electrode terminal 130. However, the electrolyte injection hole 115 may also be provided on the second sealing plate 114 or on the housing body 12 (e.g., any one of the bottom surface 112a, the long side surface 112b, or the top surface 112c). The electrolyte injection hole 115 is sealed by a sealing plug 116.

[0062] As described above, specific aspects of the technology disclosed herein include the aspects described in the following items.

[0063] Item 1: A method for manufacturing an electrical storage device, wherein the method for manufacturing the electrical storage device comprises: a preparation step of preparing an assembly, the assembly comprising a shell having an electrolyte injection hole and a resin component installed in the electrolyte injection hole, and an electrode body arranged in the shell; an injection step of injecting electrolyte into the shell from the electrolyte injection hole; and a sealing step of sealing the electrolyte injection hole after the injection step, the resin component comprising: a hollow shaft portion installed in the electrolyte injection hole; a through hole penetrating the resin component along the axis of the shaft portion; and a surplus portion integrally provided with the shaft portion and raised on the outer side of the shell at the periphery of the through hole, wherein in the sealing step, the through hole is sealed by at least melting the surplus portion.

[0064] Item 2: The manufacturing method according to Item 1, wherein in the liquid injection step, the electrolyte solution is injected by inserting a liquid injection nozzle into the through-hole, and the liquid injection nozzle is removed from the through-hole after the liquid injection.

[0065] Item 3: The manufacturing method according to Item 1 or 2, wherein the resin member is integrally molded with the housing.

[0066] Item 4: The manufacturing method according to any one of Items 1 to 3, wherein the excess material portion of the resin member is provided so as to surround the through-hole in a plan view and has a protrusion protruding in a direction away from the housing.

[0067] Item 5: The manufacturing method according to Item 4, wherein the protrusion has an inclined surface inclined toward the through hole.

[0068] Item 6: The production method according to any one of Items 1 to 5, wherein in the sealing step, the excess material portion is melted by hot stamping.

[0069] Item 7: A storage device, wherein the storage device comprises: a shell having an electrolyte injection hole; an electrode body and an electrolyte, which are arranged in the shell; and a sealing plug, which seals the electrolyte injection hole of the shell, the sealing plug is made of resin and comprises: a sealing plug shaft, which is installed in the electrolyte injection hole; and a sealing plug flange, which is integrally provided with the sealing plug shaft and extends radially of the sealing plug shaft on the outside of the shell, and a hollow cylindrical portion is provided at the end of the sealing plug shaft on the opposite side to the side where the sealing plug flange is located.

[0070] Item 8: The electrical storage device according to Item 7, wherein the sealing plug flange portion has a flow mark.

[0071] Item 9: The electrical storage device according to Item 7 or 8, wherein the sealing plug is integrally formed with the housing.

[0072] Item 10: The electrical storage device according to any one of Items 7 to 9, wherein the cylindrical portion of the sealing plug protrudes inwardly beyond the thickness of the outer case.

Claims

1. A method for manufacturing an electric storage device, characterized in that: The method for manufacturing the power storage device comprises: a preparation step of preparing an assembly including a housing having an electrolyte injection hole and a resin member mounted in the electrolyte injection hole, and an electrode body disposed in the housing; A liquid injection step of injecting electrolyte into the housing from the electrolyte injection hole; and A sealing process, after the injection process, sealing the electrolyte injection hole, The resin component has: A hollow shaft portion is mounted on the electrolyte injection hole; a through hole penetrating the resin member along the axis of the shaft portion; and The excess material portion is integrated with the shaft portion and is raised on the outer side of the housing at the periphery of the through hole. In the sealing step, the through hole is sealed by melting at least the excess material portion.

2. The method for manufacturing an electric storage device according to claim 1, wherein: In the liquid injection step, the liquid injection nozzle is inserted into the through hole to inject the electrolyte solution, and the liquid injection nozzle is pulled out from the through hole after the liquid injection.

3. The method for manufacturing an electric storage device according to claim 1 or 2, wherein: The resin component is integrally formed with the housing.

4. The method for manufacturing an electric storage device according to claim 1 or 2, wherein: The excess material portion of the resin member is provided so as to surround the through hole in a plan view and has a protrusion portion that protrudes in a direction away from the housing.

5. The method for manufacturing an electric storage device according to claim 4, wherein: The protrusion has an inclined surface inclined toward the through hole.

6. The method for manufacturing an electric storage device according to claim 1 or 2, wherein: In the sealing step, the excess material portion is melted by hot stamping.

7. An electric storage device, characterized in that: The power storage device comprises: a housing having an electrolyte injection hole; an electrode body and an electrolyte disposed in the housing; and a sealing plug for sealing the electrolyte injection hole of the housing. The sealing plug is made of resin and has: A sealing plug shaft portion is installed in the electrolyte injection hole; and The sealing plug flange is integrally formed with the sealing plug shaft and extends radially outward from the outer side of the housing toward the sealing plug shaft. A hollow cylindrical portion is provided at an end portion of the sealing plug shaft portion on the opposite side to the side where the sealing plug flange portion is located.

8. The power storage device according to claim 7, wherein The sealing plug flange portion has a melting mark.

9. The power storage device according to claim 7 or 8, characterized in that The sealing plug is integrally formed with the housing.

10. The power storage device according to claim 7 or 8, characterized in that The cylindrical portion of the sealing plug protrudes inwardly beyond the thickness of the outer shell.

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