JP6451985B2 - Nonaqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte secondary battery.

  Lithium ion secondary batteries and other non-aqueous electrolyte secondary batteries are becoming increasingly important as on-vehicle power supplies or personal computers and portable terminals. In particular, a lithium ion secondary battery that is lightweight and obtains a high energy density is preferably used as a high-output power source mounted on a vehicle.

  A non-aqueous electrolyte secondary battery used as a vehicle-mounted high-output power source has, for example, an electrode body housed in a battery case in which a case body and a lid are welded, and current collector terminals (a positive current collector terminal and a negative current collector). Terminal) penetrates through a terminal lead hole provided in the lid body and is drawn out from the inside of the battery case. In this terminal lead hole, the battery case and the current collecting terminal are insulated by interposing a gasket between the lower surface of the lid and the lead portion of the current collecting terminal.

  Specifically, for example, as shown in Patent Document 1, the projecting portion of the cylindrical current collecting terminal is formed on each of the external connection terminal, the insulator, the lid, and the gasket as to the structure near the terminal lead hole. The opening is inserted, and the upper end of the protrusion is caulked from the central axis to the outer peripheral side. By this caulking, the gasket is compressed and held between the lower surface of the lid and the lead portion of the current collecting terminal, and the battery case and the current collecting terminal are insulated.

JP 2014-7051 A

  The gasket is typically provided in the opening of the gasket, and protrudes upward along the protruding portion of the current collecting terminal, a horizontal sealing surface portion that contacts the lower surface of the lid, and the current collecting terminal And a skirt portion projecting downward along the lead portion. The gasket skirt is located near the battery case. In the conventional technique, a gap may be formed between the lower end of the skirt portion of the gasket and the current collecting member (lead portion thereof). On the other hand, there is a possibility that conductive foreign matter such as metal foil scraps that can be generated when the electrode body is slitted, or a release active material that can be generated when the electrode body is wound or flat pressed, etc. is mixed inside the battery. There is. The foreign matter moves in the electrolyte due to vehicle vibration or the like. And while a foreign material moves in electrolyte, there exists a possibility that it may enter into the clearance gap between the lower end part of the skirt part of said gasket, and a current collection terminal, and may be fixed. The foreign matter that has entered and fixed in the gap is in contact with the current collecting terminal, but since the skirt portion of the gasket is close to the battery case, it may come into contact with the battery case depending on the size of the foreign matter. When a foreign object contacts the battery case, a fine short circuit may occur between the current collecting terminal and the battery case. Since the foreign matter is fixed in the gap, such a fine short circuit lasts for a long time, and there is a concern that the battery performance may be adversely affected.

  Therefore, the present invention was created to solve the above-described conventional problems in non-aqueous electrolyte secondary batteries, and its purpose is that a gap is unlikely to occur between the lower end of the skirt portion of the gasket and the current collecting terminal. A non-aqueous electrolyte secondary battery is provided.

  The nonaqueous electrolyte secondary battery disclosed herein includes a case body having an opening, a case that covers the opening and includes a lid having a through hole, an electrode body that is accommodated in the case, A protrusion that protrudes outside the lid through the through-hole of the lid, a current collector terminal that is electrically connected to the electrode body inside the case, and a lower surface of the lid; A gasket for sealing between the lid and the current collecting terminal; The gasket has a seal surface portion along a lower surface of the lid body and a skirt portion protruding downward along the current collecting terminal, and a notch portion is provided at a lower end portion of the skirt portion of the gasket. Yes. According to such a configuration, it is possible to provide a non-aqueous electrolyte secondary battery in which a gap is hardly generated between the lower end portion of the skirt portion of the gasket and the lead portion of the current collecting terminal.

It is a fragmentary sectional view showing typically the outline of the nonaqueous electrolyte secondary battery concerning one embodiment. It is a disassembled perspective view which shows the cover body and current collection terminal of a battery which concern on one Embodiment. It is sectional drawing which shows typically the insulation structure by the side of the positive electrode of the battery which concerns on one Embodiment. It is a perspective view of the gasket before an assembly | attachment. It is a side view of the gasket before an assembly | attachment.

  Embodiments according to the present invention will be described below with reference to the drawings. Note that matters other than the matters specifically mentioned in the present specification and necessary for the implementation of the present invention (for example, a general configuration and manufacturing process of a battery that does not characterize the present invention) It can be grasped as a design matter of those skilled in the art based on the prior art. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field. Moreover, in the following drawings, the same code | symbol is attached | subjected and demonstrated to the member and site | part which show | plays the same effect | action. In addition, the dimensional relationships (length, width, thickness, etc.) in each drawing do not reflect actual dimensional relationships.

  In the present specification, the “secondary battery” refers to a general power storage device that can be repeatedly charged and discharged, and is a term including a so-called storage battery such as a lithium ion secondary battery and a power storage element such as an electric double layer capacitor. Further, the “nonaqueous electrolyte secondary battery” refers to a battery provided with a nonaqueous electrolyte (typically, an electrolytic solution containing a supporting electrolyte in a nonaqueous solvent). The “lithium ion secondary battery” refers to a secondary battery that uses lithium ions as electrolyte ions and is charged and discharged by the movement of lithium ions between positive and negative electrodes. Hereinafter, the present invention will be described in detail by taking a flat rectangular lithium ion secondary battery as an example. It should be noted that the present invention is not intended to be limited to that described in the embodiment.

  FIG. 1 is a partial cross-sectional view schematically showing an outer shape of a lithium ion secondary battery 10 according to an embodiment, and FIG. 2 is an exploded perspective view showing a lid and a current collecting terminal of the lithium ion secondary battery 10. It is. The lithium ion secondary battery 10 has a configuration in which a wound electrode body 30 including a predetermined battery constituent material is accommodated in a flat rectangular outer case 20 together with an appropriate electrolyte 90. In this embodiment, the lithium ion secondary battery 10 is a square battery, but the shape of the battery is not limited to a square shape, and may be a cylindrical shape or the like.

  The exterior case 20 includes a case main body 21 having a bottomed rectangular tube shape in which one of the narrow surfaces in the flat rectangular parallelepiped shape is an opening 21A, and a lid 22 that closes the opening 21A. Specifically, the lid 22 is fitted into the opening 21A of the case body 21, and the lid 22 is case-welded by laser welding a joint 25 between the outer edge of the outer surface of the lid 22 and the case body 21 around the opening 21A. It is fixed to the main body 21.

  The material of the outer case 20 may be the same as that used in the conventional nonaqueous electrolyte secondary battery, and is not particularly limited. An exterior case 20 mainly composed of a lightweight and highly heat conductive metal material is preferable, and examples of such a metal material include aluminum, stainless steel, and nickel-plated steel. The exterior case 20 (specifically, the main body 21 and the lid body 22) used in the present embodiment is made of aluminum or an alloy mainly composed of aluminum.

  The outer shape of the lid 22 is a substantially rectangular shape that matches the shape of the opening 21A (the opening shape of the case body 21). A safety valve 27 is provided at the center of the lid body 22 to allow the inside and outside of the case to communicate with each other and release the internal pressure when the internal pressure of the case 20 rises. Next to the safety valve 27, there is provided an inlet 28 for injecting an electrolyte when manufacturing the battery. The injection port 28 is covered with a liquid injection plug 29 and fixed by welding. As a result, the inlet 28 is sealed (sealed).

  The wound electrode body 30 is accommodated in the case main body 21 in a posture in which the winding shaft is laid sideways. The wound electrode body 30 includes a sheet-like positive electrode (positive electrode sheet) 32 and a negative electrode (negative electrode sheet) 34 in total of two sheet-like separators (separator sheets) as in the case of a wound electrode body of a normal lithium ion secondary battery. ) 36 and wound in the longitudinal direction, and the obtained wound body is pressed from the side surface direction and kidnapped.

  The material and the member itself constituting the wound electrode body 30 may be the same as the electrode body provided in the conventional lithium ion secondary battery, and there is no particular limitation. The wound electrode body 30 of the present embodiment includes a positive electrode sheet 32 having a positive electrode active material layer on a long positive electrode current collector (eg, aluminum foil), and a long negative electrode current collector (eg, copper foil). A negative electrode sheet 34 having a negative electrode active material layer thereon and a separator sheet 36 are included.

  As the positive electrode active material, an oxide-based active material having a layered structure or an oxide-based active material having a spinel structure used for a positive electrode of a general lithium ion secondary battery can be preferably used. Typical examples of such active materials include lithium transition metal oxides such as lithium cobalt oxides, lithium nickel oxides, and lithium manganese oxides. Examples of the negative electrode active material include carbon materials such as graphite (graphite), non-graphitizable carbon (hard carbon), and graphitizable carbon (soft carbon).

  A binder is used for forming the active material layer. Examples of the binder include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), carboxymethylcellulose (CMC), styrene butadiene rubber (SBR), and the like. .

  The active material layer may contain a conductive material as necessary. Examples of the conductive material include carbon materials such as carbon black (for example, acetylene black) and graphite powder, and conductive metal powder such as nickel powder.

  As the separator 36, for example, a porous sheet made of a resin such as polyethylene (PE), polypropylene (PP), polyester, cellulose, or polyamide, a nonwoven fabric, or the like can be used.

  As the electrolyte 90 interposed between the positive electrode 32 and the negative electrode 34, an electrolyte solution containing a nonaqueous solvent and a lithium salt (supporting electrolyte) that can be dissolved in the solvent can be preferably used. As the non-aqueous solvent, aprotic solvents such as carbonates, esters, ethers, nitriles, sulfones, and lactones can be used. For example, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, 1,3-dioxolane, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, acetonitrile, propionitrile, nitromethane, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, γ-butyrolactone, etc. One type or two or more types selected from non-aqueous solvents that are known to be usable for electrolytes of secondary batteries can be used.

Examples of the supporting electrolyte include LiPF ₆ , LiBF ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiC (SO ₂ CF ₃ ) ₃ , LiClO _4, etc., one or more selected from various lithium salts known to be capable of functioning as a supporting electrolyte in the electrolyte of a lithium ion secondary battery can be used. The concentration of the supporting electrolyte (supporting salt) is not particularly limited, and can be the same as, for example, the electrolytic solution used in a conventional lithium ion secondary battery. Typically, a nonaqueous electrolytic solution containing a supporting electrolyte at a concentration of about 0.1 mol / L to 5 mol / L (for example, about 0.8 mol / L to 1.5 mol / L) can be preferably used. .

  A positive electrode current collector terminal 40 and a negative electrode current collector terminal 80 are connected to the positive electrode sheet 32 and the negative electrode sheet 34, respectively. These current collecting terminals 40 and 80 pass through terminal lead-out holes (through holes) 242 and 244 for positive electrode and negative electrode provided at one end and the other end in the longitudinal direction of the lid body 22, respectively, and the exterior case 20. It is pulled out from the inside. As shown in FIGS. 1 and 2, the positive electrode current collecting terminal 40 is connected to a positive electrode internal terminal 420 that is mainly located inside the outer case 20 and a positive electrode external terminal 460 that is mainly located outside the outer case 20. It has a configuration. The negative electrode current collecting terminal 80 also has a configuration in which a negative electrode internal terminal 820 and a negative electrode external terminal 860 formed in substantially the same shape as the positive electrode side are connected.

  The lower end 422A of the positive electrode internal terminal 420 is connected to the positive electrode sheet 32 by, for example, ultrasonic welding. The positive electrode internal terminal 420 is formed following a plate-like (strip-like) first lead portion 422 extending substantially perpendicularly from the lower end 422A to the lid body 22 and the upper end of the first lead portion, and substantially perpendicular to the upper end ( In FIG. 2, a plate-like second lead portion 424 that is bent and extends substantially parallel to the inner surface of the lid body 22 from the front side to the back side of the drawing, and substantially perpendicular to the battery outward direction from the center portion of the plate surface of the second lead portion. And a protruding portion 426 extending in the direction. The protruding portion 426 is configured as a rivet portion, and the positive internal terminal 420 and the positive external terminal are formed by caulking the rivet portion through the terminal lead hole 242 and the through hole (rivet hole) 462A of the positive external terminal 460. 460 is connected (fastened). As a constituent material of the positive electrode internal terminal 420 and the positive electrode external terminal 460, a metal material having good conductivity is preferable, and aluminum is typically used.

  The positive external terminal 460 is connected to the first connecting portion 462 having a through hole 462A through which the protruding portion 426 can be inserted before the caulking, and the first connecting portion 462 to the center in the longitudinal direction of the lid body 22. And a second connection portion (outer end portion) 464 formed to be stepped outward. The second connection portion 464 is formed with a bolt insertion hole 464A through which the leg portion 674 of the bolt 670 can be inserted, as well shown in FIG. A leg portion 674 of the bolt 670 is passed through the bolt insertion hole 464A from below, and a connecting member (not shown) for external connection is attached to the leg portion 674 protruding upward from the second connection portion 464, and a nut (FIG. By tightening (not shown), the connecting member can be coupled (fixed) to the positive external terminal 460.

  In the caulking, the gasket 50 is sandwiched between the wall surface of the lid 22 surrounding the terminal lead-out hole 242 and the second lead portion 424, and the insulator 60 is sandwiched between the wall surface and the first connection portion 462 of the external terminal. Done in By such caulking, the positive electrode current collecting terminal 40 is fixed to the lid body 22, and the gasket 50 is compressed between the lid body 22 and the second lead portion 424 of the positive electrode current collector terminal 40, thereby sealing the terminal extraction hole 242. Has been. Further, the gasket 50 insulates the outer case 20 (the lid body 22) and the positive electrode current collector terminal 40 (second lead portion 424), and the insulator 60 allows the outer case 20 (the lid body 22) and the positive electrode external terminal 460 ( The first connection portion 462) is insulated. The insulating structure near the terminal lead hole 242 will be described later.

  The insulator 60 is provided between the mounting portion 620 sandwiched between the wall surface of the lid body 22 surrounding the terminal lead hole 242 and the first connection portion 462 of the external terminal, and between the second connection portion 464 of the external terminal and the lid body 22. And an extension 640 extending in the direction. The attachment portion 620 has a dish portion that extends along the outer surface of the lid body 22. The first connection part 462 of the external terminal is arranged in accordance with the depression of the dish part.

  The extension portion 640 has a rectangular opening shape having a long side in the longitudinal direction of the insulator 60 (corresponding to the longitudinal direction of the lid body 22), and a bolt receiving hole that can receive the head 672 of the bolt 670. 642 is formed. The head 672 is formed so that the shape in a cross section perpendicular to the axis of the bolt 670 is a rectangular shape that is slightly smaller than the opening shape of the bolt receiving hole 642. The bolt 670 is disposed (attached) so that the rotation of the bolt 670 is restricted by the insertion of the head 672 into the bolt receiving hole 642 (co-rotation is prevented), and the leg 674 protrudes through the bolt insertion hole 464A. Yes.

  Next, the insulating structure of the lid body 22 and the current collecting terminal 40 by the gasket 50 of the lithium ion battery 10 of this embodiment will be described with reference to FIG. FIG. 3 schematically shows an insulating structure on the positive electrode side, and is a cross-sectional view that is perpendicular to the wide surface of the outer case 20 (parallel to the narrow surface) and includes the axis of the terminal lead hole 242. Here, the axis of the through hole refers to an axis that passes through the center of the through hole and is perpendicular to the radial direction of the through hole.

  In FIG. 3, the gasket 50 is sandwiched between the lid body 22 and the positive electrode current collecting terminal 40. The gasket 50 includes a boss portion 51 projecting upward along the projecting portion 426 of the positive electrode current collecting terminal 40, a horizontal seal surface portion 52 contacting along the lower surface of the lid 22, and the second current collector terminal 40. And a skirt portion 53 that protrudes downward along the side surface of the lead portion 424. The side surface of the terminal lead hole 242 of the lid 22 is insulated from contact with the positive current collecting terminal 40 by the boss portion 51 of the gasket 50. Further, the lower surface of the lid body 22 is insulated from contact with the positive electrode current collector terminal 40 by the seal surface portion 52 of the gasket 50. Further, the insulator 60 is sandwiched between the positive electrode external terminal 460 and the upper surface of the lid body 22 to prevent the positive electrode external terminal 460 and the lid body 22 (the outer case 20) from contacting each other, and these are insulated. Yes. The lower end portion of the skirt portion 53 is in close contact with the positive electrode current collecting terminal 40 (side surface of the second lead portion 424). Although not shown in FIGS. 2 and 3, a notch portion is provided at the lower end portion of the skirt portion 53 of the gasket 50. Hereinafter, the notch will be described.

  FIG. 4 is a perspective view of the gasket 50 before assembly. In the present embodiment, the gasket 50 has a square shape as illustrated, but the shape of the gasket is not limited thereto. The gasket 50 has a boss portion 51, a seal surface portion 52, and a skirt portion 53. And the skirt part 53 has the notch part 54 in the lower end part. The notch portion 54 is located near both end portions in the lateral direction (direction along the long side) of the skirt portion. Therefore, a total of eight notches 54 are provided, two on each surface of the skirt 53 of the gasket 50.

  The lower end portion of the skirt portion 53 is in close contact with the positive electrode current collector terminal 40 (side surface of the second lead portion 424) because of the action of the notch portion 54. This action is considered to work as follows. FIG. 5 is a side view of the gasket 50 before assembly. The gasket 50 has a notch portion 54 having a mountain-shaped curved shape in the vicinity of both ends of each long side of the lower end portion of the skirt portion 53. In the process of manufacturing the lithium ion secondary battery 10, the gasket 50 is deformed. When the gasket 50 is deformed, stress acts in the direction of the arrow shown in the notch 54 on the right side of FIG. When the stress acts in this way, when the gasket 50 is deformed and changes dimensions, the dimensional change occurs in a direction in which the lower end portion of the skirt portion 53 of the gasket 50 is in close contact with the current collecting terminal 40, and as a result, the skirt portion. The lower end portion of 53 is in close contact with the positive electrode current collecting terminal 40.

In the manufacturing process of the lithium ion secondary battery 10, as a factor that the gasket 50 can be deformed,
-Compression load (for example, 2000 N or more) in the caulking process of the protruding portion 426 of the current collecting terminal 40;
The welding heat in the welding process between the battery case body 21 and the lid 22;
-Heating in a cell drying process for drying the inside of the battery outer case 20 (for example, 100 ° C or higher);
-Contact with the electrolyte in the electrolyte injection process;
Is mentioned. The deformation of the gasket 50 may be performed in at least one of the caulking process, the welding process, the cell drying process, and the electrolyte solution injection process. Therefore, the gasket 50 can be deformed at an arbitrary timing. According to the present embodiment, since the lower end of the skirt portion of the gasket and the current collecting terminal are closely contacted with each other by the deformation of the gasket, it is performed by a process normally performed when the lithium ion secondary battery 10 is manufactured. There is no need for an additional step for bringing the lower end of the skirt portion into close contact with the current collecting terminal, and the productivity of the lithium ion secondary battery is not impaired.

  Here, the larger the dimension (depth) B in the vertical direction of the notch portion 54, the larger the dimensional change when the gasket is deformed, and the lower end portion of the skirt portion 53 is in the inner diameter direction of the skirt portion 53 (current collection). Terminal direction). However, if the vertical dimension B is too large, the strength at the notch 54 of the gasket 50 tends to be weak. Therefore, the vertical dimension B of the notch 54 is preferably 5% or more and 50% or less of the vertical dimension (height) A of the skirt 53 of the gasket 50, but is not limited thereto.

  The gasket 50 having such a notch 54 can be manufactured by using a mold having a shape corresponding to the notch in advance, and molding the gasket material by, for example, injection molding or hot press molding. . Alternatively, a gasket without a notch can be obtained by first molding and providing a notch by cutting.

  4 and 5, the notch 54 is provided in a mountain-shaped curved shape. However, as long as stress acts in the direction in which the lower end of the skirt 53 is in close contact with the current collecting terminal 40, the notch 54 The shape is not limited to this. The notches 54 are provided in the vicinity of both ends of the long sides of the lower end of the skirt 53, but as long as stress acts in the direction in which the lower end of the skirt 53 is in close contact with the current collecting terminal 40. The position of the notch 54 is not limited to this. In the present embodiment, eight notches 54 are provided. However, as long as stress acts in the direction in which the lower end of the skirt 53 is in close contact with the current collector terminal 40, the number of notches 54 is equal to this. Not limited.

  As a constituent material of the gasket 50, a general material used as a gasket of a nonaqueous electrolyte secondary battery, for example, polyphenylene sulfide resin (PPS), polyimide resin, polyamideimide resin, polyetheretherketone resin (PEEK). , Polyether ketone ketone resin (PEKK), polyether sulfone resin (PES), polyolefin resin (eg, polypropylene (PP), polyethylene (PE)), fluororesin (eg, perfluoroalkoxyalkane (PFA), polytetra A resin material based on a resin such as fluoroethylene (PTFE) (typically a resin material having a composition in which the base resin accounts for more than 50% by mass of the resin component) may be used. In form, shape memory resin (eg, styrene-butadiene system) Jo memory resin, using urethane-based shape-memory resin). When the gasket 50 is made of a shape memory resin, when the gasket 50 is deformed, the stress acting in the direction of the current collecting terminal 40 at the lower end of the skirt portion 53 of the gasket 50 can be further increased. The effect of eliminating the gap between the lower end portion of the portion 53 and the current collecting terminal 40 can be further enhanced.

  As a constituent material of the insulator 60, a general material used as an insulator of a non-aqueous electrolyte secondary battery, for example, polyamide, polyacetal (POM), tetrafluoroethylene-perfluoroalkyl vinyl ether resin (PFA), methacrylic resin , PPS, polyimide resin, polyamideimide resin, PEEK, PEKK, PES, urea resin, phenol resin, melamine resin and other resin materials can be preferably used. Alternatively, a resin material based on a resin such as a polyolefin resin such as polypropylene (PP) or polyethylene (PE); a fluororesin such as perfluoroalkoxyalkane (PFA) or polytetrafluoroethylene (PTFE); Good.

  The structure on the negative electrode side in the lithium ion secondary battery 10 of the present embodiment is substantially the same as that on the positive electrode side except for the material of the negative electrode current collector terminal 80. That is, one end of the negative electrode current collecting terminal 80 is connected to the negative electrode sheet 34 by, for example, resistance welding. The negative electrode current collecting terminal 80 includes a negative electrode internal terminal 820 and a negative electrode external terminal 860 that are formed in substantially the same shape as the positive electrode internal terminal 420, and a protruding portion (rivet portion) of the negative electrode internal terminal 820 is provided as the negative electrode external terminal 860. The negative internal terminal 820 and the negative external terminal 860 are connected by caulking to the first connection portion. The caulking is performed by sandwiching the gasket 50, the lid body 22 and the insulator 60 between the terminals 820 and 860, as in the positive electrode side. The gasket 50 has the above-described notch 54 as in the positive electrode side. The negative external terminal 860 is formed in a staircase shape having a first connection portion and a second connection portion. Bolts 670 are installed in the bolt insertion holes provided in the second connection portion from the bottom to the top, and are configured so that a connection member for external connection can be coupled (fixed) to the leg portion 674. . As a constituent material of the negative electrode internal terminal 820 and the negative electrode external terminal 860, a metal material having good conductivity is preferable, and copper is typically used. The materials and shapes of the gasket 50 and the insulator 60 are the same as those on the positive electrode side.

  As described above, since the skirt portion 53 of the gasket 50 can be brought into close contact with the current collecting terminal 40 in the process of the conventional method for manufacturing a lithium ion secondary battery, the lithium ion secondary battery 10 of this embodiment is a conventional one. It can be manufactured according to the method.

  As described above, in the lithium ion secondary battery 10 of the present embodiment, the lower end portion of the skirt portion 53 of the gasket 50 is in close contact with the positive electrode current collecting terminal 40 (side surface of the second lead portion 424). Therefore, there is no room for conductive foreign matters such as metal foil scraps and separation active materials in the electrolyte to enter between the lower end portion of the skirt portion 53 of the gasket 50 and the positive electrode current collecting terminal 40. Therefore, in the lithium ion secondary battery 10 of the present embodiment, a fine short circuit between the current collecting terminal and the battery case, which may be caused by foreign matter entering between the lower end of the gasket skirt and the current collecting terminal, is prevented. Has been. Therefore, the lithium ion secondary battery 10 of this embodiment has high battery performance reliability.

  The lithium ion secondary battery 10 of this embodiment is suitable for a power source for driving a vehicle such as a hybrid vehicle or an electric vehicle. The power source for driving the vehicle may be an assembled battery in which a plurality of secondary batteries are combined.

  As mentioned above, although the specific example of this invention was demonstrated in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

DESCRIPTION OF SYMBOLS 10 Lithium ion secondary battery 20 Case 21 Case main body 22 Lid body 27 Safety valve 28 Inlet 30 Electrode body 32 Positive electrode 34 Negative electrode 36 Separator 40,80 Current collecting terminal 50 Gasket 51 Boss part 52 Seal surface part 53 Skirt part 54 Notch part 60 Insulator 90 Electrolyte 242 Terminal lead-out hole 420 Internal terminal 426 Projection 460 External terminal 670 Bolt

Claims (1)

A case main body having an opening, and a case provided with a lid that closes the opening and has a through hole;
An electrode body housed inside the case;
A current-collecting terminal that has a protruding portion that is inserted through the through-hole of the lid and projects outside the lid, and is electrically connected to the electrode body inside the case;
A non-aqueous electrolyte secondary battery comprising a gasket that contacts a lower surface of the lid and seals between the lid and the current collecting terminal,
The gasket has a seal surface portion along the lower surface of the lid, and a skirt portion that protrudes downward from an end portion of the seal surface portion along the current collecting terminal,
A nonaqueous electrolyte secondary battery in which a notch is provided at a lower end of a skirt of the gasket.

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