JP2001210297A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery capable of releasing a gas in a short time during the cleavage of a safety valve. SOLUTION: An electrode element 2 consists of a wound positive electrode, a negative electrode and a laminated film of a separator. One end of an outer can 1 is provided with a cover 7, a PTC element 3, and the safety valve 6 caulked and sealed via a gasket 8. A central portion of the safety valve 6 is provided with a protrusion 6a. The protrusion 6a is welded to a sub-disc 4 through a center hole 11c of a disc 11. The disc 11 is fixed to the inside of the safety valve 6 via a disc holder 12. An outer periphery hole 11d of the disc 11 are formed at six places ranging over an outer periphery portion 11f, a thin portion 11e and a separate portion 11g. The thin portion 11e extends nearly along a circle with a symmetrical point of the center hole 11c as a center.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In recent years, portable information devices such as laptop computers and word processors, camera-integrated video tape recorders, AV devices such as liquid crystal televisions, and mobile communication devices such as mobile phones have been remarkably developed. There is a demand for a small, lightweight, high energy density secondary battery for the battery used. Until now, aqueous secondary batteries such as lead batteries, nickel cadmium batteries, nickel hydride batteries and the like have been used, but they are not sufficient with respect to demands for weight reduction, high energy density, and the like.

[0003] Recently, non-aqueous electrolyte secondary batteries have attracted great interest and expectations as clean batteries having a high energy density. Here, a conventional non-aqueous electrolyte secondary battery will be described with reference to FIGS.

FIG. 4A is a sectional view of a conventional non-aqueous electrolyte secondary battery. In this non-aqueous electrolyte secondary battery, the electrode element 2 is accommodated in a cylindrical bottomed outer can 1, and a non-aqueous electrolyte (not shown) is injected into the outer can 1. Electrolyte is impregnated in the electrode element 2.

In the electrode element 2, a film-like positive electrode and a film-like negative electrode are laminated via a film-like separator, and the laminated film is spirally wound around, for example, a cylindrical core. It becomes.

An insulating thin plate is arranged on both sides of the electrode element 2, and the free ends of the leads 9 and 10 of the electrode element 2 are led out of the insulating thin plate. The free end of the negative electrode lead 10 is welded to the bottom surface of the outer can 1 serving as an electrode terminal lead-out portion.

At one end of the outer can 1, a lid 7, a PTC element 3, and a safety valve 6 are caulked via a gasket 8 and sealed. As a result, the lid 7, the PTC element 3, and the safety valve 6 are electrically connected.

The safety valve 6 has a projection 6a formed at the center thereof and protruding toward the electrode element 2 side. The protrusion 6a passes through the center hole 11c of the disc 11,
It is welded to the subdisk 4. Thus, the protrusion 6a is electrically connected to the sub-disk 4.

The disk 11 is fixed inside the safety valve 6 via a disk holder 12. Here, the shape of the disk 11 will be described in detail. FIG. 4B is a plan view of a disk used in a conventional non-aqueous electrolyte secondary battery.

In FIG. 4B, the outer edge portion 11a is a band-shaped plate which is a part of the disk 11 and has a circular outer shape. The outer edge portion 11a supports the entire disk 11 by being fixed to the gasket 8 itself.

The recess 11b is a part of the disk 11, and has a flat shape and is continuous with the outer edge 11a. The disk 11 has a center hole 11c.
The center hole 11c is a circular hole centered on the symmetry point of the disk 11. The outer peripheral hole 11d is a substantially rectangular hole having a semicircular portion on the side of the center hole 11c, and its central axis is directed in the radial direction.

The subdisk 4 shown in FIG. 4A is a thin disk having a thin shape, and is welded to the center of the disk 11 and to the electrode element 2 side of the disk 11. A positive electrode lead 9 is welded to the electrode element 2 side of the sub-disk 4. Thus, the sub-disk 4 and the positive electrode lead 9 are electrically connected.

Next, the operation of the safety valve used in the conventional non-aqueous electrolyte secondary battery will be described with reference to FIG.
Here, the safety valve has two mechanisms, a current cutoff mechanism and a cleavage mechanism. First, before describing the current cutoff mechanism and the cleavage mechanism, the normal state of the safety valve will be described. FIG.
FIG. 1A is a cross-sectional view showing a state of a safety valve 6 in a normal state of a conventional nonaqueous electrolyte secondary battery.

In FIG. 2A, although the sub-disk 4 covers the center hole 11c of the disk 11, the diameter of the sub-disk 4 is small, so that the outer hole 11d provided near the outer periphery of the disk 11 is not closed. in this way,
Since the outer peripheral hole 11d of the disk 11 is not closed, gas present in the battery can pass. On the other hand, since the safety valve 6 has no hole, gas existing in the battery cannot escape to the outside, and the airtight state is maintained.

Next, the operation of the safety valve in the current cutoff mechanism will be described. FIG. 5B is a cross-sectional view of a conventional non-aqueous electrolyte secondary battery showing the function of a safety valve in a current cutoff state.

When gas is generated in the outer can 1 for some reason, the internal pressure increases. At this time, the generated gas passes through the outer peripheral hole 11d of the disk 11, and the safety valve 6
Apply pressure to the inside surface of the. Thereby, the safety valve 6 is deformed outward.

Due to the deformation of the safety valve 6, at the welding portion between the projection 6a of the safety valve 6 and the sub-disk 4, the sub-disk 4 existing around the welding portion is torn off by the shearing force. As described above, when the protruding portion 6a is separated from the sub-disk 4, the electrical connection between the positive electrode lead 9 and the lid 7 is cut off.

Next, the operation of the safety valve cleavage mechanism will be described. FIG. 2C is a cross-sectional view illustrating a function of a safety valve in a cleavage state of a conventional nonaqueous electrolyte secondary battery. When the pressure in the outer can 1 becomes higher than the pressure in the above-described current interruption state, the safety valve 6 itself is opened. As described above, when the safety valve 6 ruptures, the gas generated inside the battery first passes through the outer peripheral hole 11d of the disk 11, then passes through the rupture portion 6b of the safety valve 6, and further passes through the vent hole 7a of the lid 7. Passed and released to the outside.

[0019]

Here, the generated gas can easily pass through the cleavage portion 6b of the safety valve 6. However, in the disk 11, the gas can only pass through the outer peripheral hole 11d, and it is difficult to pass the gas.

To solve this problem, it is conceivable to increase the opening area of the outer peripheral hole 11d. However, if the opening area is increased, it becomes difficult to secure the mechanical strength of the disk 11 itself. In order to ensure this mechanical strength, it is conceivable to increase the thickness of the disk 11, but it is necessary to reduce the capacity of the battery by increasing the thickness. For these reasons, it is practically difficult to increase the opening area of the outer peripheral hole 11d.

As a result, when gas is generated in the outer can 1, there is a problem that the generated gas cannot be released to the outside in a short time with the conventionally used disk.

The present invention has been made in view of such problems, and has as its object to provide a non-aqueous electrolyte secondary battery that can release gas in a short time when a safety valve is opened.

[0023]

A non-aqueous electrolyte secondary battery according to the present invention comprises: a tubular outer can containing an electrode element;
At least a disk and a safety valve are provided, the disk has a center hole, and the safety valve has a projection projecting toward the electrode element at the center thereof, and the projection is formed at the center of the disk. A nonaqueous electrolyte secondary battery connected to a lead of the electrode element through a hole, wherein the disk has a linear thin portion.

Further, the non-aqueous electrolyte secondary battery of the present invention is a non-aqueous electrolyte secondary battery having the above-described structure, in which the thin portion is substantially along a circle centered on the center of symmetry of the center hole.

According to the non-aqueous electrolyte secondary battery of the present invention, since the disk has the linear thin portion, the gas passage area when the safety valve is opened increases.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention relating to a non-aqueous electrolyte secondary battery will be described below with reference to FIGS. First, the configuration of the nonaqueous electrolyte secondary battery according to the present embodiment will be described. FIG. 1A is a cross-sectional view of the nonaqueous electrolyte secondary battery according to the present embodiment. This embodiment is a case where a lithium-doped, non-aqueous electrolyte lithium secondary battery is provided with a non-aqueous electrolyte, comprising a positive electrode and / or a negative electrode provided with a material capable of undoping, and The present invention is not limited to this embodiment and the example of FIG. 1A.

In this embodiment, nickel (N
i) An electrode element 2 is accommodated in a plated iron-made cylindrical bottomed outer can 1, and a nonaqueous electrolyte (not shown) is injected into the outer can 1. Is the electrode element 2
Impregnated. The outer can 1 is not limited to the cylindrical type as described above. In addition, other cylindrical batteries such as a prismatic battery may be used.

In the electrode element 2, a film-like positive electrode and a film-like negative electrode are respectively laminated via a film-like separator, and the laminated film is spirally wound around, for example, a cylindrical core. It becomes.

The positive electrode and the negative electrode of the electrode element 2 are
For example, aluminum (Al) foil and copper (C
u) A positive electrode active material and a negative electrode active material are applied to both sides of a strip-shaped current collector foil made of a foil.

One end of a positive electrode lead 9 made of Al and one end of a negative electrode lead 10 made of Ni are welded from opposite ends of each current collector foil of each of the positive electrode and the negative electrode, as shown in FIG. 1A. For example, the positive electrode lead 9 is led out of the electrode element 2 from the center of the electrode element 2, and the negative electrode lead 10 is led from the outer peripheral side of the electrode element 2.

The electrode element 2 is inserted into the outer can 1 with the lead-out side of the negative electrode lead 10 on the bottom side of the outer can 1. Insulating thin plates are arranged on both sides of the electrode element 2, and the leads 9 and 10 of the electrode element 2 are provided outside the insulating thin plate.
Is derived. And the free end of the negative electrode lead 10 is
For example, it is welded to the bottom surface of the outer can 1 serving as an electrode terminal lead-out portion.

In the above-described electrode element 2, the positive electrode active material of the positive electrode is, for example, a material capable of undoping and re-doping Li, for example, an active material L of lithium transition metal composite oxide.
i _x MO ₂ (M is, Co, Ni, one or more transition metals of Mn, 0.4 ≦ x ≦ 1.1) composite oxide represented by, among others _{LiCoO 2, LiNiO 2, LiMn 2} O 4 , etc. Is preferred. Such lithium transition metal oxides include, for example, carbonates, nitrates, oxides of Li, Co, Ni, and Mn.
It is obtained by mixing hydroxides or the like as starting materials in an amount corresponding to the composition and firing the mixture in a temperature range of 600 ° C to 1000 ° C.

The negative electrode active material of the negative electrode is, for example, L
a substance that can be doped or undoped with i, for example, a low-crystalline carbon material obtained by firing at a relatively low temperature of 2000 ° C. or less, artificial graphite or natural graphite obtained by treating a material that is easily crystallized at a high temperature of about 3000 ° C. Is used. For example, pyrolytic carbons, cokes, graphites, glassy carbons, organic polymer compound fired products (furan resin or the like fired at an appropriate temperature and carbonized), carbon fiber, activated carbon, and the like can be used. is there.

The low-crystalline carbon material is preferably a material obtained by calcining a furan resin, petroleum pitch, or the like at a temperature of less than 1500 ° C. and having a (002) plane spacing of 3.70 angstroms by wide-angle X-ray diffraction. As described above, the true density is 1.7.
A carbonaceous material that is less than 0 g / cm ³ and does not have an exothermic peak at 700 ° C. or more in differential thermal analysis in an air stream is used. As the graphite powder, a carbonaceous material having a (002) plane spacing of less than 3.42 angstroms by a wide-angle X-ray diffraction method is preferably used. These carbonaceous materials have a large amount of Li doping and undoping and are excellent in charge / discharge cycle life performance, and the anode material is most suitable for the equipment to be used in combination with the cathode material Combinations can be selected.

The separator can be made of, for example, a microporous film of polyethylene, polypropylene, or Teflon.

The non-aqueous electrolyte comprises an organic solvent and an electrolyte dissolved therein. Alternatively, a so-called polymer electrolyte obtained by mixing a non-aqueous electrolyte with a polymer compound, or a polymer electrolyte obtained by mixing or binding an electrolyte to a polymer compound can be used. Examples of the organic solvent include cyclic carbonates such as ethylene carbonate and propylene carbonate, dimethyl carbonate, chain carbonates such as diethyl carbonate, γ-butyrolactone, γ
-One or more of cyclic esters such as parolelactone, chain esters such as ethyl acetate and methyl propionate, and ethers such as tetrahydrofuran and 1,2-dimethoxyethane can be used. As the electrolyte, for example, a lithium salt that dissolves in the solvent used and exhibits ionic conductivity, such as Li
PF ₆ , LiBF ₄ , LiClO ₄ , LiCF ₃ S
O ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO
₂ ) One or more types such as ₃ can be used.

A lid 7, a PTC element 3, and a safety valve 6 are crimped through a gasket 8 and sealed at one end of the outer can 1. That is, for example, stainless steel, N
A lid 7 serving as a positive electrode side terminal lead-out portion made of i or Fe, a ring-shaped PTC element 3 having, for example, positive temperature characteristics, and a safety valve 6 made of, for example, Al disposed inside the lid 7 are sandwiched by a gasket 8 and It is crimped to the open end of the can 1 and sealed. As a result, the lid 7, the PTC element 3, and the safety valve 6 are electrically connected.

The safety valve 6 has a projection 6a projecting toward the electrode element 2 at the center thereof. The projection 6a is welded to the sub-disk 4 (described in detail below) through a center hole 11c of the disk 11 (described in detail later). Thus, the protrusion 6a is electrically connected to the sub-disk 4.

The disk 11 is fixed inside the safety valve 6 via a disk holder 12. This disk 1
1 is made of a metal plate such as Al. The disk holder 12 has a function of electrically insulating the safety valve 6 and the disk 11 from each other.

Here, the shape of the disk 11 will be described in detail. FIG. 1B is a plan view of a disk used in the nonaqueous electrolyte secondary battery according to the present embodiment. The outer edge portion 11a of the disk 11 is a band-shaped plate that is a part of the disk 11 and has a circular outside. Also, this outer edge portion 11a
By fixing itself to the gasket 8, it supports the entire disk 11.

The outer peripheral portion 11f and the separating portion 11g are a part of the disk 11, and have a thin portion 11e (to be described in detail later).
Through a continuous plate. Also, the outer peripheral portion 11f
The separation portion 11g is continuous with the outer edge portion 11a, and has a concave portion on the electrode element 2 side from the outer edge portion 11a.

The disk 11 has a center hole 11c. The center hole 11c is a circular hole centered on the symmetry point of the disk 11, and is formed in the separation portion 11g of the disk 11. The center hole 11c is provided with the safety valve 6
Has the function of passing through the projection 6a.

The outer peripheral hole 11d has the outer peripheral portion 11f, the thin portion 1
1e and the separation portion 11g. The outer peripheral hole 11d is a substantially rectangular hole having a semicircular portion on the side of the center hole 11c, and its central axis is directed in the radial direction. Further, the outer peripheral hole 11d has a function of passing gas generated in the battery (to be described later in detail).

The disk 11 has a linear thin portion 11e. The thin portion 11e is substantially along a circle centered on the symmetry point of the center hole 11c. Also, the thin portion 11
e intersects with the outer peripheral hole 11d.

The position of the thin portion 11e is not limited to the position described above. That is, the thin portion 11e
Is preferably in the area outside the sub-disk 4 and inside the outermost periphery of the outer peripheral portion 11f. When the thin portion 11e is inside the sub-disk 4, the thin portion 11e
Of the thin portion 11
If e is outside the outermost periphery of the outer peripheral portion 11f, the thin portion 1
This is because the shearing of 1e becomes impossible.

It does not matter whether the thin portion 11e itself intersects with the outer peripheral hole 11d as described above or forms a complete circle without intersecting with the outer peripheral hole. Further, the shape of the thin portion 11e is not limited to the circular shape as described above. in short,
Any shape can be adopted as long as the separation portion 11g can be separated from the outer peripheral portion 11f.

The thickness of the thin portion 11e is 0.2 mm. On the other hand, the outer peripheral portion 11f and the separation portion 11g
Has a thickness of 0.4 mm. Here, the thin portion 11
Although 0.2 mm was adopted as the thickness of e, the thickness is not limited to this. Needless to say, the thickness can be appropriately changed depending on the value of the pressure to be cleaved. Further, not only the thickness of the thin portion 11e is made uniform throughout the thin portion, but also by making the thickness different for a part thereof, it is possible to provide a portion where cracking is likely to occur.

Next, regarding the sub-disk 4, FIG.
This will be described with reference to FIG. The sub-disk 4 is a thin disk having a thin shape, and is made of, for example, a metal such as Al. The sub-disk 4 is welded to the center of the disk 11 and to the electrode element 2 side of the disk 11. The free end of the positive electrode lead 9 is welded to the surface of the sub-disk 4 on the electrode element 2 side. Thus, the sub-disk 4 and the positive electrode lead 9 are electrically connected. As a result,
The projection 6 a of the safety valve 6 is electrically connected to the positive electrode lead 9.

Next, the operation of the safety valve and the disk used in the nonaqueous electrolyte secondary battery according to the present embodiment will be described. Here, the safety valve has two mechanisms, a current cutoff mechanism and a cleavage mechanism. Further, the disc has a cleavage mechanism.

First, before describing the current interrupting mechanism and the tearing mechanism, the normal state of the safety valve and the disk will be described. FIG. 2A shows the safety valve 6 and the disk 11 of the non-aqueous electrolyte secondary battery according to the present embodiment in a normal state.
It is sectional drawing which shows a mode. FIG. 2A shows the upper part of FIG. 1A.

In FIG. 2A, although the sub-disk 4 covers the center hole 11c of the disk 11, the diameter of the sub-disk 4 is small, so that the outer hole 11d provided near the outer periphery of the disk 11 is not closed. Further, since the outer peripheral hole 11d of the disk 11 is not closed as described above, gas existing in the battery can pass through. On the other hand, since the safety valve 6 has no hole, gas existing in the battery cannot escape to the outside, and the airtight state is maintained. This state is the normal state in FIG. 2A.

Next, the operation of the safety valve in the current cutoff mechanism will be described. FIG. 2B is a cross-sectional view illustrating the function of the safety valve in the current cutoff state for the nonaqueous electrolyte secondary battery according to the present embodiment.

When gas is generated in the outer can 1 for some reason, the internal pressure increases. At this time, the generated gas passes through the outer peripheral hole 11d of the disk 11, and the safety valve 6
Apply pressure to the inside surface of the. As a result, the safety valve 6 is pushed outward and expands and deforms outward. Due to this deformation, the internal volume of the battery increases, and the internal pressure can be reduced correspondingly.

Due to the deformation of the safety valve 6, at the welding portion between the projection 6a of the safety valve 6 and the sub-disk 4, the sub-disk 4 around the welding portion is torn off by the shearing force. As described above, the protrusion 6a and the sub-disk 4 are separated from each other, so that the positive electrode lead 9
And the electrical connection between the lid 7 is cut off. That is, the positive electrode lead 9 is connected to the sub-disk 4 and the projection 6a.
Through the safety valve 6, the PTC element 3 and the lid 7
The electrical connection between the positive electrode lead 9 and the lid 7 is also cut off when the sub-disk 4 and the projection 6a are separated from each other as described above.

Here, the deformation of the safety valve 6 will be described in more detail. As can be seen from FIG. 2B, when the safety valve 6 deforms, it largely deforms at 6k and 6l.
That is, 6 which is the outermost periphery of the flat area inside the safety valve 6.
k and 6l very close to the projection 6a. The other parts, that is, the protrusion 6a are hardly deformed, and the flat part outside the protrusion 6s is also slightly deformed.

As can be seen from FIG. 2B, the distance between the bending points 6k and 6l is large. Therefore, due to the deformation of the safety valve 6, the projection 6a is largely separated from the sub-disk 4. As described above, since the projection 6a and the sub-disk 4 are largely separated from each other, an effect that the current interruption can be reliably performed is generated.

Next, the operation of the safety valve cleavage mechanism will be described. FIG. 2C is a cross-sectional view showing the action of the safety valve and the disk in the split state of the nonaqueous electrolyte secondary battery according to the present embodiment. The pressure inside the outer can 1 is
When the pressure becomes higher than the pressure in the above-described current interruption state, the safety valve 6 itself is opened. Thus, the safety valve 6
Is cleaved, but when the disk 11 is not cleaved, the gas generated inside the battery first passes through the outer peripheral hole 11d of the disk 11, then passes through the cleavage portion 6b of the safety valve 6, and The lid 7 is released to the outside through the vent hole 7a.

Next, the operation of the disk cleavage mechanism will be described with reference to FIG. 2C. When the pressure becomes higher than the pressure at which the above-described safety valve splitting mechanism operates, the disc 11 splitting mechanism operates. That is, the separation unit 11g of the disk 11 separates from the disk 11. As a result, the separation part 11g rises, and a cleavage part 11h is formed around the separation part 11g. As a result, the gas generated inside the battery is transferred to the outer peripheral hole 11 of the disk.
In addition to d, the cleavage 11h of the disk 11 can also pass at the same time. Further, the generated gas is supplied to the safety valve 6.
Through the cleavage portion 6b, and then through the ventilation hole 7a of the lid 7 to be released to the outside.

Here, the state of cleavage of the disk 11 is shown in FIG.
This will be described in detail with reference to FIG. FIG. 3 is a plan view showing a state of the disk used for the nonaqueous electrolyte secondary battery according to the present embodiment in a cleavage state. When gas is generated inside the battery, first, the gas passes through the outer peripheral hole 11d of the disk 11. Further, when the gas pressure increases, the separation unit 1
A large pressure acts on 1 g of the surface on the electrode element 2 side. When such a large pressure acts, a large shear stress acts on the thin portion 11e of the disk 11. Here, since the thin portion 11e is mechanically weakest, it is easily sheared by this shearing force. As a result, the separation unit 11g is separated from the disk 11 in a state as shown in FIG. 3B. Then, a cleavage portion 11h is formed in a portion where the thin portion 11e is located around the separation portion 11g.

As described above, when the disk 11 is cleaved, the gas passage area when the safety valve is cleaved increases. In the above description, the disk is torn after the safety valve is torn, but the order is not limited to this. That is, depending on the state of generation of pressure inside the battery,
The case where the disk is opened simultaneously with the opening of the safety valve may be used. In any of these conditions, the disk cleavage mechanism works effectively and can increase the gas passage area. As a result, gas can be released in a short time when the safety valve is opened.

When the disk is torn, the separation part of the disk may come into contact with the safety valve and be electrically connected by floating from the disk. However, when gas is released from the inside of the battery to the outside, the battery itself cannot perform its function as a battery.Therefore, there is a problem even if the separator and the safety valve are electrically connected. Absent. Further, in the above-described embodiment, the description has been given of the cylindrical non-aqueous electrolyte secondary battery. However, the application range of the present invention is not limited to the cylindrical non-aqueous electrolyte secondary battery. That is, it goes without saying that the present invention can be applied to other batteries having a pressure release mechanism. In addition, the present invention is not limited to the above-described embodiment, but can adopt various other configurations without departing from the gist of the present invention.

[0062]

The present invention has the following effects. Since the disk has a linear thin portion, gas can be released in a short time when the safety valve is opened.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a non-aqueous electrolyte secondary battery according to the present invention,
It is a top view of the disk used for this non-aqueous electrolyte secondary battery.

FIG. 2 shows a non-aqueous electrolyte secondary battery according to the present invention.
It is sectional drawing which shows the action | operation of a safety valve and a disc in a normal state, a current cutoff state, and a cleavage state.

FIG. 3 is a plan view showing a state of a disk used in the nonaqueous electrolyte secondary battery according to the present invention in a cleavage state.

FIG. 4 is a cross-sectional view of a conventional non-aqueous electrolyte secondary battery and a plan view of a disk used in the non-aqueous electrolyte secondary battery.

FIG. 5 is a cross-sectional view showing a function of a safety valve of a conventional non-aqueous electrolyte secondary battery in a normal state, a current interruption state, and a cleavage state.

[Explanation of symbols]

1 ‥‥ Outer can, 2 ‥‥ Electrode element, 3 ‥‥ PTC element, 4
{Sub disk, 6} Safety valve, 6a Projection, 6
b {Cleaved part, 7} Lid, 7a # Vent, 8 # Gasket, 9 # Positive electrode lead, 10 # Negative electrode lead, 1
1 ‥‥ disk, 11a ‥‥ outer edge, 11b ‥‥ recess,
11c center hole, 11d outer peripheral hole, 11e thin part, 11f outer peripheral part, 11g separation part, 11h cleavage part, 12 disk holder

Claims (2)

[Claims] At least one disk and a safety valve are provided on one end side of a cylindrical outer can in which an electrode element is stored, wherein the disk has a center hole, and the safety valve is provided at a central portion of the electrode element side. A non-aqueous electrolyte secondary battery connected to a lead of the electrode element through a center hole of the disk, wherein the disk has a linear thin portion A non-aqueous electrolyte secondary battery comprising: 2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the thin portion is substantially along a circle centered on a point of symmetry of the center hole.