JP2003092148A - Non-aqueous secondary battery - Google Patents

Abstract

(57) [Problem] To provide an electrode body in which a positive electrode and a negative electrode are spirally wound through a separator in a battery can, and a hollow cylindrical shape provided in a central gap portion of the electrode body. In the non-aqueous secondary battery accommodating the center pin and the center pin, it is possible to prevent a problem that the edge of the center pin penetrates through the separator when the center of the electrode body is deformed, thereby causing an internal short circuit. SOLUTION: A center pin 16 is formed by processing a metal material into a cylindrical shape, and both end surfaces 1 of the metal material extending along the axial direction thereof.
6a and 16a are opposed or close to each other with a gap therebetween, and corner drop portions 16b and 16b are provided at or near the both end surfaces 16a and 16a.

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a non-aqueous secondary battery.
In particular, non-aqueous secondary batteries whose electrodes are spiral electrodes
Things. [0002] 2. Description of the Related Art For miniaturization of electronic devices and spread of mobile phones, etc.
As a result, two power sources with high energy density
The demand for the next battery is increasing more and more. At present,
As a high-capacity secondary battery that meets demands,
LiCoO which is a lithium-containing composite oxide_Two , LiNi
O_Two Or LiMn_Two O_Four As a negative electrode active material
Practical use of lithium ion secondary battery using carbon-based material
Have been. This lithium-ion secondary battery is
The dynamic voltage is as high as 3.6V, and the conventional nickel-cadmium
It is about three times the average driving voltage of a pond or nickel-metal hydride battery.
In addition, a carbon-based material is used as the negative electrode active material,
Lithium is the light metal that provides mobility
(Ion), it can be expected to be lighter. [0003] A lithium ion secondary battery is a conventional lithium ion battery.
Unlike non-aqueous secondary batteries that use metal as the negative electrode,
Into a paste in which the substance is dispersed in a solution together with a binder,
Using this paste, a belt-like positive electrode current collector and negative electrode current collector
Form a coating containing each active material on both sides to form a positive electrode
And a negative electrode. And those strips
The positive electrode, the negative electrode, and the separator are laminated in this order, and the product
After the layer electrode body is spirally wound around the winding core,
The winding core is removed to form an electrode body and inserted into a battery can.
Thus, a battery is configured. In addition, the positive electrode
In addition to the positive electrode active material and the binder,
Conductive additives such as carbon-based materials
You. [0004] Non-aqueous electrolytes having a spiral electrode structure as described above
In secondary batteries, the battery
Has the problem that internal short circuits may occur in the
You. In other words, in non-aqueous secondary batteries, repeated charging and discharging
Therefore, a phenomenon that the volume of the electrode increases is observed. Swirl
Since the wound electrode is housed in a metal can,
Cannot expand, but the center is
Since the voids remain, the volume increase
The center of the electrode
The electrode near the core deforms and breaks through the separator,
And the negative electrode may come into contact with each other and cause an internal short circuit.
Will result. [0005] The electrode central part of such a non-aqueous secondary battery changes.
In order to prevent internal short circuit caused by shaping,
For example, in Japanese Patent Application Laid-Open No. 4-332481, FIG.
A gap 56c of about 10% of the outer periphery of the battery as shown in FIG.
Deformation of the center of the electrode using a hollow cylindrical center pin 56
Non-aqueous secondary batteries have been proposed in which the volume is reduced. [0006] SUMMARY OF THE INVENTION
Generally, a metal material is cut into a predetermined length and this metal material
Is manufactured by a method of cylindrical processing. On the spot
In this case, metal material that can be bent into a cylindrical shape means cost reduction
From both ends are welded along its axial direction.
Processed so that they face each other with a slight gap
Is done. [0007] However, such a center pin
With the structure, when external pressure greater than external is applied to the battery,
As the electrode body is crushed, the center pin is
You will be crushed. Crushing force evenly in gaps
If you join, it does not matter much to the left, but either
The problem arises when a force is applied in a biased manner. In other words, power
Is crushed, but the other
The center pin part will stand up against this
To the edge of the end face generated during the cutting of metal material.
Therefore, the separator breaks through and the positive and negative electrodes
This causes a problem of causing an internal short circuit. Or
No slit is provided to solve this problem
It is conceivable to use a cylindrical center pin.
In general, processing is very labor-intensive, and is expensive
There is a problem that the cost cannot be reduced. The present invention has been developed to solve the above-mentioned conventional problems.
A center that suppresses deformation at the center of the electrode
-By devising the shape of the pin,
An object is to prevent or suppress an internal short circuit. [0009] In order to achieve the above object,
Therefore, the present invention provides a hollow cylindrical center in the central space of the electrode body.
Non-aqueous secondary battery containing
The pin is a cylindrical body made of metal material, and
The two end surfaces of the metal material extending along
It is composed of adjacent ones, and both end faces or its vicinity
Formed into an R shape, or formed by turning the end face
In this configuration, a corner drop portion is provided. like this
According to such a configuration, the center pin is crushed in the gap.
When the center pin end face is upright
Are also formed in an R-shape at both ends, or end faces are turned back
Since there is a corner drop formed by processing, the end face
Effective prevention of internal short circuit due to edge
it can. [0010] Embodiments of the present invention will be described below.
Will be explained. In the present invention, particularly as the positive electrode active material,
Without limitation, for example, LiCoO_Two Etc.
Titanium cobalt oxide, LiMnO_Two Etc. lithium man
Gun oxide, LiNiO_Two Such as lithium nickel oxidation
Substances, manganese dioxide, vanadium pentoxide, chromium oxide
Metal oxides, etc., or composite oxides having these as the basic structure
(For example, a replacement with a different metal element) or disulfur
Metal sulfides such as titanium nitride and molybdenum disulfide
Or as a mixture of two or more, or solid solutions thereof
Used as Also, LiMO_Two Or LiM_Two O_Four
And M is a metal such as Co, Ni, Mn, Fe, Cu, etc.
Lithium-containing metallization containing at least one element
It may be a compound. Among them, LiCoO_Two , LiNiO
_Two , LiMnO_Two , LiM_Two O_Four Open circuit voltage when charging
Is a lithium-containing composite oxide exhibiting 4 V or more based on Li.
High energy density is obtained when used as a positive electrode active material.
Is preferred in that The positive electrode contains, for example, the positive electrode active material.
If necessary, use flake graphite, carbon black, etc.
A paste containing an auxiliary agent and further containing a binder is used as a positive electrode current collector.
On the positive electrode current collector and dry at least
Manufactured through the process of forming a coating film containing a substance and a binder
Is done. In adjusting the positive electrode active material-containing paste
The binder is used as a solution previously dissolved in a solvent.
It can be adjusted by mixing with the solid particles such as the positive electrode active material.
Is preferred. In the present invention, the thickness of the positive electrode current collector
Therefore, 5 to 60 μm, particularly preferably 8 to 40 μm,
In addition, the thickness of the positive electrode active material-containing coating film is one sided.
30-300 μm, especially 50-150 μm is preferred
No. The material used for the negative electrode is lithium ion
Can be doped (occluded) and de-doped (released)
In the present invention, such a resource may be used.
Substances that can dope and undope with lithium ions
Is called a negative electrode active material. This anode active material is particularly limited.
Although not specified, for example, graphite, pyrolytic carbons,
Baking of cokes, glassy carbons, and organic polymer compounds
Body, mesocarbon microbeads, carbon fiber, activated carbon, etc.
Carbon; aluminum, silicon, tin, indium, etc.
Alloy with Titanium, or charge and discharge at low voltage near lithium
Use oxides such as silicon, tin, indium, etc.
Can be. When a carbon material is used as the negative electrode active material,
As the carbon material, those having the following characteristics are preferable.
No. That is, the inter-plane distance (d00) of the (002) plane of the crystal.
Regarding 2), 0.350 nm or less is preferable, and more preferable.
It is preferably 0.345 nm or less, more preferably 0.340 n.
m or less. Also, the crystallite size in the c-axis direction (Lc)
Is preferably 3 nm or more, more preferably 8 nm or more.
nm or more, more preferably 25 nm or more. Soshi
The average particle size of the carbon material is 8 to 20 μm, particularly 1 μm.
0 to 15 μm is preferred. The purity is 99.9 mass
% Or more is preferable. The negative electrode may be, for example, a negative electrode active material.
Polyvinylidene fluoride, polytetrafluoroethylene, etc.
As needed, and if necessary, a conductive additive.
Into a paste with a solvent.
The paste is applied to a negative electrode current collector made of copper foil or the like and dried,
By forming a negative electrode active material-containing coating on the negative electrode current collector
Is produced. The binder is dissolved in a solvent in advance.
After that, it may be mixed with a negative electrode active material or the like. The thickness of the negative electrode current collector is 5 to 60.
μm, particularly preferably 8 to 40 μm.
The thickness of the material coating is 30 to 300 μm per side.
m, particularly preferably 50 to 150 μm. The binder used for the positive electrode and the negative electrode is
Of thermoplastic resins, polymers having rubber elasticity,
Sugars can be used as one kind or a mixture of these
You. Specifically, polytetrafluoroethylene, polyf
Vinylidene fluoride, polyethylene, polypropylene, ethyl
Len-propylene-diene copolymer, styrene butadiene
Rubber, polybutadiene, fluorine rubber, polyethylene rubber
Oxide, polyvinylpyrrolidone, polyester resin,
Kuril resin, phenol resin, epoxy resin, polyvinyl
Alcohol, hydroxypropylcellulose, etc.
Loin resin, and the like. As the positive electrode current collector and the negative electrode current collector,
For example, aluminum, copper, nickel, stainless steel,
Metal foil such as titanium, expanded metal, net,
Metal, etc. are used.
Luminium foil is preferable, and copper is particularly preferable as the negative electrode current collector.
preferable. In manufacturing the positive electrode and the negative electrode,
Positive electrode active material-containing paste and negative electrode active material-containing paste
As a coating method when applying to the current collector, for example, extrusion
Coater, reverse roller, doctor blade, etc.
First, various coating methods can be adopted. In the non-aqueous secondary battery of the present invention, a liquid
Degradation (hereinafter referred to as "electrolyte") is used. Ingredient
Physically, an organic solvent system in which a solute is dissolved in an organic solvent
Use water electrolyte. The solvent in this case is not particularly limited.
Use of chain ester as main solvent
Is particularly preferred. Examples of such chain esters include
For example, diethyl carbonate (DEC), dimethyl carbonate
Carbonate (DMC), ethyl methyl carbonate (EM
C), ethyl acetate (EA), methyl propionate (M
Organic solvents having a chain COO-bond such as P).
It is. This chain ester is said to be the main solvent of the electrolyte.
This means that these chain esters are present in 50% of the total electrolyte solvent.
Occupies more volume than volume%, especially
When the chain ester is 65% by volume or more in the total electrolyte solvent,
The reason is that the chain ester accounts for 70% by volume or more of the total electrolyte solvent.
Occupied, and among them, chain ester
Most preferably, it accounts for at least 75% by volume of the solvent. However, the solvent for the electrolytic solution is the above-mentioned chain
Improve battery capacity compared to using only ester
Therefore, an ester having a high dielectric constant of the chain ester (attraction)
It is preferable to use a mixture of esters having an electric conductivity of 30 or more.
New All electrolyte solvent of such high dielectric constant ester
The amount occupied therein is 10% by volume or more, especially 20% by volume.
% Or more is preferable. Examples of the ester having a high dielectric constant include, for example,
For example, ethylene carbonate (EC), propylene carbonate
Nate (PC), butylene carbonate (BC), γ-
Butyrolactone (γ-BC), ethylene glycol sal
Fight (EGS) and the like.
Cyclic structures such as carboxylate and propylene carbonate
Preferred, especially cyclic carbonates,
Physically, ethylene carbonate (EC) is the most preferred
No. Further, other than the above-mentioned ester having a high dielectric constant,
Examples of usable solvents include, for example, 1,2-dimethoxyethyl
Tan (1,2-DME), 1,3-dioxolan (1,
3-DO), tetrahydrofuran (THF), 2-methyl
Le-tetrahydrofuran (2-Me-THF), diethyl
Ruether (DEE) and the like. In addition,
Organic or imide-based organic solvents, sulfur-containing or fluorinated
Elemental organic solvents and the like can also be used. As the solute of the electrolyte, for example, LiCl
O_Four , LiPF₆ , LiBF_Four , LiAsF₆ , LiS
bF₆ , LiCF_Three SO_Three , LiC_Four F₉ SO_Three , Li
CF _Three Co_Two , Li_Two C_Two F_Four (SO_Three )_Two , LiN
(CF_Three SO_Two )_Two , LiC (CF_Three SO_Two )_Three , Li
C_n F_{2n + 1}SO_Three (N ≧ 2) alone or in combination of two or more
Used together. In particular, LiPF₆ And LiC_Four F₉ S
O_Three And the like are preferable because of good charge / discharge characteristics. electrolytic
The concentration of solute in the liquid is not particularly limited
Is 0.3 to 1.7 mol / dm^Three , Especially 0.4 to 1.5 mol
/ Dm^Three The degree is preferred. In the present invention, the electrolyte is
Solid or gel electrolytes can be used in addition to liquids.
Wear. Such electrolytes include inorganic solid electrolytes.
Or polyethylene oxide, polypropylene oxide
Solid electrolytes based on metal or their derivatives, etc.
Can be mentioned. As the separator used in the present invention, for example,
For example, a nonwoven fabric or a microporous film is used. Of the nonwoven fabric
Materials include polypropylene, polyethylene, and polyether.
Tylene terephthalate, polybutylene terephthalate, etc.
There is. As the material of the microporous film,
, Polyethylene, polyethylene-propylene copolymer
Etc. The separator has sufficient strength and is electrically
Those that can hold a large amount of lysate are preferable, and such a viewpoint
From 10 to 50 μm in thickness and 30 to 70% porosity
Made of polypropylene, polyethylene or ethylene
Microporous films or nonwovens made of propylene copolymer are preferred
No. In the present invention, the lead of the negative electrode is
Resistance welding and ultrasonic welding to the negative electrode manufactured as
Is welded to the exposed part of the negative electrode current collector.
The cross-sectional area of the pole lead
0.1mm to reduce resistance and reduce heat generation^Two Less than
Above, 1.0mm^Two The following is preferable, and 0.3 mm^Two 0.7mm
^Two The following is more preferred. As the material of the negative electrode lead
Nickel is commonly used for copper, titanium,
Stainless steel or the like can also be used. The center pin used in the present invention is
It is made of a metal material to secure the extreme strength. Money
Although the material is not particularly limited, productivity,
Those excellent in workability, hardness and corrosion resistance are preferred.
Such metals as stainless steel, nickel, titanium
And steel. The shape of the center pin is a hollow cylindrical shape.
It is formed. In the present invention, a metal material cut into a predetermined shape
By R processing on both ends of the
A bent corner is provided in advance by bending. From a cost perspective
It is preferable to provide a corner-dropping portion by folding.
Insert the center pin tip into the center of the electrode body.
It is preferable to form it in a tapered shape to make it easier.
Good. The non-aqueous secondary battery of the present invention includes, for example,
Between the sheet-like positive electrode and the negative electrode thus produced.
Overlap with a parator interposed and spirally wound
The electrode structure with a wound structure is nickel-plated.
After inserting into the iron or stainless steel
Insert the center pin into the gap, then inject the electrolyte solution
After that, it is produced through a sealing process. In addition, the battery
Usually reduces the gas generated inside the battery to a certain pressure.
When the battery rises, it is discharged to the outside of the battery,
An explosion-proof mechanism is installed to prevent
You. [0032] Next, the present invention will be described more specifically based on examples.
explain. However, the present invention is limited to only these examples.
It is not done. (Example) First, a positive electrode was formed as follows.
Produced. LiCoO as positive electrode active material_Two The 190 mass
Parts, 4 parts by mass of acetylene black as a conductive aid,
6 parts by mass of polyvinylidene fluoride as an adhesive,
Phenylphosphonic acid as a phosphoric acid compound having a substituent
Is uniformly mixed so as to be 0.2% by mass with respect to the positive electrode active material.
And further add 60 parts by mass of N-methylpyrrolidone and mix.
Then, a paste-like positive electrode paint was prepared. This paste
The positive electrode paint through a 70 mesh net
After removing the aluminum strip, a 15μm thick aluminum strip
Apply evenly on both sides of the positive electrode current collector made of foil, dry
A positive electrode active material-containing coating film was formed. The thickness of the coating after drying is
The electrode mass per unit area is 25.0 mg.
/cm^Two Met. After drying the strip-shaped electrode body, the thickness 17
It was compression molded to 0 μm. After that, cut to the specified size
And weld the aluminum lead to a sheet
Got the pole. Next, a negative electrode was prepared as follows. negative
Graphite-based carbon material as the polar active material
(002) plane distance (d002) = 0.337 nm;
Crystallite size (Lc) in c-axis direction = 95 nm, average grain size
Carbon material with characteristics of diameter 10μm and purity 99.9% by mass
Material), 14 parts by mass of polyvinylidene fluoride
Dissolved in 190 parts by mass of N-methylpyrrolidone
To prepare a paste-like negative electrode paint. This page
A paste-like negative electrode paint is formed from a 10-μm-thick strip-shaped copper foil.
Uniformly on both sides of the negative electrode current collector
A quality-containing coating was formed. The thickness of the coating film after drying is 243μ.
m, and the mass of the electrode per unit area is 12.0 mg / cm.^Two so
there were. After drying the band-shaped electrode body, the thickness is reduced to 175 μm.
It was compression molded. After that, cut it to the specified size,
The lead member made of a metal was welded to obtain a sheet-shaped negative electrode. Further, the electrolytic solution was prepared as follows.
Was. Methyl ethyl carbonate (MEC) and ethylene carbonate
-Carbonate (EC) was mixed at a volume ratio of 2: 1
LiPF in the mixed solvent₆ To 1.2 mol / dm^Three Dissolve
Thus, a non-aqueous electrolyte was obtained. Subsequently, the non-aqueous secondary battery is manufactured as follows.
Produced. After drying the positive electrode and the negative electrode, the positive electrode is
A 25 micron thick microporous polyethylene film
Overlaid on the negative electrode via a parator, spirally wound and swirled
The spirally wound electrode body is housed in a fixed cylindrical battery can.
Then, the lead bodies of the positive electrode and the negative electrode were welded. Next, the outer space shown in FIG.
Made of stainless steel with a diameter of 3.4 mm, an inner diameter of 2.8 mm and a length of 55 mm
After the center pin 16 is inserted, the electrolytic solution is placed in the battery can.
And sufficiently permeated into a separator or the like. afterwards,
After sealing, pre-charging and aging, as shown in Figure 1
A cylindrical non-aqueous secondary battery having a simple structure was manufactured. Referring to the battery shown in FIG.
In the positive electrode, 2 is the negative electrode. However, in FIG.
Was used to prepare the positive electrode 1 and the negative electrode 2 to avoid complication.
The current collector and the like used are not shown. Positive electrode 1 and
The negative electrode 2 is spirally wound via a separator 3,
A battery having a spirally wound electrode body and the above-described electrolyte 4
It is housed in a can 5. The battery can 5 is made of stainless steel and has a bottom
Prior to inserting the spirally wound electrode body,
An insulator 6 made of propylene is provided. The sealing portion of the battery can 5 is placed under the state shown in FIG.
Sealing plate 7, insulating packing 10, explosion-proof valve 9, terminal
A plate 8 is provided. Also, between these and the battery can 5
To seal the inner peripheral surface of the sealing portion of the battery can 5
An annular gasket 12 made of polypropylene is attached.
You. The sealing plate 7 is made of aluminum and has a disc shape.
And a thin portion 7a is provided at the center thereof.
pressure for causing the battery internal pressure to act on the explosion-proof valve 9 around a
In this configuration, a hole is provided as an inlet 7b. Of the sealing body 7
The projection 9a of the explosion-proof valve 9 is welded to the upper surface of the thin portion 7a.
Thus, a welded portion 11 is formed. In addition, the above-mentioned sealing
The thin portion 7a provided on the plate 7, the protruding portion 9a of the explosion-proof valve 9, etc.
Indicates the cut surface for easy understanding on the drawing.
The contour line behind the cut surface is not shown. Ma
In addition, between the thin portion 7a of the sealing plate 7 and the projection 9a of the explosion-proof valve 9
The welded portion 11 is also used for easy understanding on the drawing.
It is shown in an exaggerated state. The terminal plate 8 is made of a rolled steel plate and has a nickel plating on the surface.
A hat is provided with a stick and the periphery is a collar.
The terminal plate 8 is provided with a gas outlet 8a.
You. The explosion-proof valve 9 is made of aluminum and has a disk shape.
In the center, the tip is on the power generation element side (the lower side in FIG. 1).
Having a protruding portion 9a and a thin portion 9b
As described above, the lower surface of the protruding portion 9a
7 is welded to the upper surface of the thin portion 7a to form a welded portion 11.
are doing. The insulating packing 10 is made of polypropylene.
It has an annular shape and is arranged above the peripheral edge of the sealing plate 7,
An explosion-proof valve 9 is arranged on the top of the
At the time of peeling, the periphery of the sealing plate 7 and the explosion-proof valve 9 are insulated.
Between the two so that the liquid electrolyte does not leak from between the two.
The gap is sealed. 13 is a lead body having one end connected to the positive electrode 1
It is. The lead body 13 is made of aluminum,
The mouth plate 7 and the positive electrode 1 are connected. Above the electrode body
An edge 14 is arranged. The negative electrode 2 and the bottom of the battery can 5
Are connected by a lead body 15 made of nickel. In this battery, the thin portion 7 of the sealing plate 7
a and the protruding portion 9a of the explosion-proof valve 9 come into contact at the welded portion 11,
The peripheral edge of the explosion-proof valve 9 and the peripheral edge of the terminal plate 8 come into contact with each other,
1 and the sealing plate 7 are connected by a lead 13 on the positive electrode side.
Therefore, in a normal state, the positive electrode 1 and the terminal plate 8 are connected to a lead.
Body 13, sealing plate 7, explosion-proof valve 9 and their welded parts 1
1 provides electrical connection and functions normally as an electrical circuit
I do. Also, be sure that the battery does not generate heat due to overcharging.
When the battery becomes abnormal, gas is generated inside the battery.
If the internal pressure of the battery rises due to
The central part of the explosion-proof valve 9 is in the direction of the internal pressure (in FIG.
Direction), and is thereby integrated at the welded portion 11
Shear force acts on the thin portion 7a of the sealing plate 7
The portion 7a is broken or the projection 9a of the explosion-proof valve 9 is sealed.
The welding portion 11 with the thin portion 7a of the mouth plate 7 is peeled off,
Shut off, and then the thin-walled portion 9b provided on the explosion-proof valve 9
The gas is cleaved and gas is discharged from the gas outlet 8a of the terminal plate 8 to the outside of the battery.
Battery to prevent battery rupture.
You. In such a battery, the characteristic features of the present invention
The center pin 16 separates the positive electrode 1 and the negative electrode 2 from each other.
Of the electrode body spirally wound via the radiator 3
It is inserted in the gap. This center pin 16 is
2 (a) and (b), the stainless steel plate was
It is composed of a cylinder processed. Specifically,
The center pin 16 in the example is a stainless steel plate bent in a cylindrical shape.
The two end faces 16a extending along the axial direction
Facing each other (in the case of proximity without welding)
Stainless steel plate into a cylindrical shape
The both end faces 16a, 16a inside (the center pin 16
By turning it back so that it is not square.
The corner dropping portions 16 are provided near the both end surfaces 16a.
b and 16b. Corner drop part 16b ・ 1
6b is, for example, a center pin from the vertical direction in FIG.
16 when a crushing force is applied to the
End faces (end face edge portions) 16a, 16a extending along
Not to jump outside,
In order not to damage the electrode body,
Roundness attached to the folded part near both end faces, that is, R
It is. The tip 16d of the center pin 16 (shown in the figure)
In the example, the opposite end 16e is also the same).
Taper to facilitate insertion of the pin into the part
It is formed in a shape. (Comparative Example) Inserted in the center gap of the electrode body
Implemented except that there was no corner drop on the center pin
A non-aqueous secondary battery was produced in the same manner as in the example. (Evaluation)
For example, for the battery of the comparative example, fix the battery to an appropriate jig.
Pressurizes the battery with 13kN force from above, through the metal plate
Then, I checked the occurrence situation of internal short circuit. Here,
A pressure is intentionally applied to only one of the center pin gaps.
The center pin during the assembly phase.
The gap position was adjusted. And the battery can part that will be the relevant location
Apply the above pressure after marking the place
did. In the battery according to the embodiment, a crushing force is applied.
Although no internal short circuit was found,
In the battery of the comparative example, occurrence of an internal short circuit was observed. internal
Analysis of the battery after the occurrence of a short-circuit indicates that the standing center pin
The separator breaks at the edge of the end face of
And the center pin edge reaches the negative electrode
Was. [0050] As is clear from the above, the present invention provides:
The center pin with the corner drop part is located at the center of the spiral electrode body.
By using a non-aqueous secondary battery inserted in the gap,
Internal short circuit even when pressure is applied from
There is no security and high security can be ensured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic longitudinal sectional view showing one example of a non-aqueous secondary battery of the present invention. FIGS. 2A and 2B show an example of a center pin of the present invention, wherein FIG. 2A is a perspective view of the center pin, and FIG. 2B is an enlarged cross-sectional view cut in a direction orthogonal to the axial direction. is there. FIG. 3 is a perspective view showing a conventional center pin. [Description of Signs] 1 Positive electrode 2 Negative electrode 3 Separator 16 Center pin 16a End face 16b extending along the axial direction of the center pin Corner dropping portion

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Claims (1)

Claims: 1. An electrode body in which a positive electrode and a negative electrode are spirally wound via a separator in a battery can, and a hollow member provided in a center gap portion of the electrode body. In a nonaqueous secondary battery accommodating a cylindrical center pin, the center pin is formed by processing a metal material into a cylindrical shape, and both end surfaces of the metal material extending along the axial direction are opposed to or close to each other via a gap. A non-aqueous secondary battery characterized in that a corner drop portion is provided at or near the both end faces.