JPH06187970A - Nonaqueous electrolyte battery - Google Patents

Abstract

PURPOSE:To break a quick current increase which occurs at the time of overcharging or shortcircuitting by a PTC element composing a sealing cover group by setting an aperture position of a ring part of an inner cover body to coincide with a vent hole of the PTC element or on the inner side of the vent hole. CONSTITUTION:An electrode body 2 is contained at an inner part of an outer can 1 of a cylindrical form having a bottom which also acts as a negative electrode terminal. The electrode body 2 is composed by winding a laminated body of a positive electrode 3, a separator 4 and a negative electrode 5 spirally. A sealing cover group 8 is caulked and fixed to an upper aperture part through an insulationg gasket 9. The cover group 8 comprises a reinforcement plate 13 held by an inner cover body 10 facing the electrode body 2, and a ring part 12 disposed on it through a valve film 12, a PTC element 14 on the ring part 12, and an outer cover body 15. The inner cover body 10 at an aperture position of the ring part 12 is set to coincide with a vent hole 18 of the element 14, or it is formed on the inner side of the vent hole 18, thereby the whole body 14 of the element 14 is disposed on the ring part 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte battery having a sealing lid which also has an explosion-proof function.

[0002]

2. Description of the Related Art Recently, a secondary battery using a non-aqueous electrolyte such as a lithium battery using a non-aqueous electrolyte or a lithium-ion battery has been widely used in portable electronic devices and the like. Such a secondary battery is characterized by having a high electromotive force of 3 V or 4 V, unlike a conventional battery, and its excellent performance is drawing attention.

By the way, in the above-described secondary battery, the electrode body including the positive electrode and the negative electrode housed in the outer can may undergo a chemical change to increase the internal pressure and cause rupture.
For example, a non-aqueous electrolyte battery such as a lithium secondary battery is supplied with a current higher than usual, that is, in a so-called overcharged state,
If a short circuit occurs due to incorrect use and a large current flows, the non-aqueous electrolyte solution in the electrode body may be decomposed to generate gas. When such gas gradually fills the outer can and the internal pressure in the outer can rises, the battery finally bursts.

For this reason, conventionally, there is known a non-aqueous electrolyte battery having a sealing lid group which also has an explosion-proof function and a terminal as shown in FIG. 2 in order to prevent the above-mentioned rupture of the battery. . That is, the electrode body 22 is housed in the outer can 21 which also serves as the negative electrode terminal. The electrode body 22 is
A laminate of the positive electrode 23, the separator 24, and the negative electrode 25 is spirally wound. The electrode body 2
A cutout portion 26 is formed in a portion of the separator 24 arranged on the outer periphery of the outer can 2 serving also as the negative electrode terminal.
And is in electrical contact with the negative electrode 25 exposed from the notch 26. An insulating plate 27 having a hole in the center is arranged at the bottom of the outer can 21 to prevent the positive electrode 23 of the electrode body 22 from electrically contacting the outer can 21 which also serves as the negative electrode terminal. The sealing lid group 28, which also functions as an explosion-proof function and a terminal, is caulked to the upper end opening of the outer can 21 via an insulating gasket 29. The sealing lid group 28 is arranged via a dish-shaped inner lid body 30 arranged to face the electrode body 22, and a valve membrane 31 formed of a flexible thin film on the inner lid body 30, The inner lid 3
A reinforcing plate 33 made of an insulating material, which is sandwiched by an annular portion 32 formed by bending the peripheral edge of the inside 0, and a PTC element 3 arranged on the annular portion 32 of the inner lid 30.
4 and a cap-shaped outer lid 35 which is arranged on the PTC element 34 with its peripheral edge abutting. The inner lid body 30, the reinforcing plate 33, the PTC element 34, and the outer lid body 35 respectively have a gas vent hole 36,
37, 38, 39 are opened. Positive electrode lead 40
Has one end connected to the positive electrode 23 of the electrode body 22 and the other end connected to the lower surface of the inner lid body 30 of the sealing lid group 28.

In the non-aqueous electrolyte battery having such a structure, when a current larger than usual, for example, a large current is applied due to an overcharged state, the above-mentioned non-aqueous electrolyte battery is located between the inner lid body 30 and the outer lid body 35. The resistance of the PTC element 34 rapidly increases as the temperature rises, and the current is stopped from flowing, whereby the battery is prevented from bursting. In addition, when the large current causes decomposition gas to be generated in the outer can 21 in which the electrode body 22 and the non-aqueous electrolyte solution are accommodated, and the internal pressure rises, and when a predetermined pressure is reached, the decomposition gas causes the decomposition of the internal lid body. The valve membrane 31 disposed above the gas vent hole 36 is broken through the gas vent hole 36 opened in 30. As a result, the decomposed gas is broken at the valve membrane 31, the reinforcing plate 33, the PC.
Escape to the outside through the gas vent holes 37, 38, 39 opened in the T element 34 and the external lid 35,
Batteries are prevented from bursting.

However, in the above-mentioned non-aqueous electrolyte battery provided with the conventional explosion-proof function and the sealing lid group 28 which also serves as a terminal, the PTC element 34 arranged thereon is formed by the annular portion 32 of the inner lid 30. Since the pressure is applied locally, the characteristic of the PTC element 34 in which the resistance value rapidly increases as the temperature rises is impaired. As a result, even if a current larger than normal, for example, a large current is given due to an overcharged state, the PTC element 34 does not operate well and the rapidly flowing current cannot be interrupted well, so the internal pressure of the outer can 21 suddenly increases. There was a problem that the battery burst and the battery burst.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a non-aqueous electrolyte battery capable of satisfactorily interrupting a rapid increase in current that occurs during overcharge or short circuit by the PTC element constituting the sealing lid group. It is the one we are trying to provide.

[0008]

A non-aqueous electrolyte battery according to the present invention comprises an outer can and a positive electrode housed in the outer can.
An electrode body in which a separator and a negative electrode are spirally wound,
A non-aqueous electrolyte contained in the outer can, and a sealing lid group that also functions as an explosion-proof function and a terminal airtightly caulked and fixed by an insulating gasket to an upper end opening of the outer can,
The sealing lid group is sandwiched between an inner lid body arranged to face the electrode body and an annular portion formed on the inner lid body via a valve membrane, the inner lid body being bent inward. Reinforcing plate, a PTC element arranged on the annular portion of the inner lid, an outer lid arranged on the PTC element with its peripheral edge abutting, the inner lid, the reinforcing plate, the In a non-aqueous electrolyte battery comprising a PTC element and a gas vent hole opened in the outer lid,

It is characterized in that the opening position of the annular portion of the inner lid is aligned with the gas vent hole position of the PTC element or is located inside the gas vent hole. Hereinafter, a non-aqueous electrolyte battery according to the present invention is shown in FIG.
Will be described in detail with reference to.

For example, an electrode body 2 is housed in a bottomed cylindrical outer can 1 which also serves as a negative electrode terminal. The electrode body 2
Has a structure in which a laminate of the positive electrode 3, the separator 4, and the negative electrode 5 is spirally wound. It should be noted that the notch 6 is formed in the portion of the separator 4 arranged on the outer periphery of the electrode body 2.
Is formed and is in electrical contact with the outer can 1 also serving as the negative electrode terminal and the negative electrode 5 exposed from the notch 6.
An insulating plate 7 having a hole in the center is arranged at the bottom of the outer can 1 to prevent the positive electrode 3 of the electrode body 2 from electrically contacting the outer can 1 also serving as the negative electrode terminal.

Sealing lid group 8 which also has an explosion-proof function and a terminal
Is caulked and fixed to the upper end opening of the outer can 1 through an insulating gasket 9. The sealing lid group 8 includes a dish-shaped inner lid 10 arranged to face the electrode body 2, and a valve membrane 11 formed from a flexible thin film on the inner lid 10.
And a reinforcing plate 13 made of an insulating material and sandwiched by an annular portion 12 formed by bending the peripheral edge of the inner lid 10 inward, and the annular portion 1 of the inner lid 10.
2 and the PTC element 1 and the PTC element 1
4 is a hat-shaped outer lid body arranged with its peripheral edge abutting on
It is composed of 5 and. Gas vent holes 16, 17, 18, and 19 are opened in the inner lid body 10, the reinforcing plate 13, the PTC element 14, and the outer lid body 15, respectively. The positive electrode lead 20 has one end connected to the positive electrode 3 of the electrode body 2 and the other end connected to the lower surface of the inner lid body 10 of the sealing lid group 8.

[0012] The inner lid 1 which constitutes the sealing lid group 8
The opening position of the annular portion 12 of 0 is the PTC element 1
4 is located inside the gas vent hole 18 position. That is, the area of the annular portion 12 is made larger than the area of the PTC element 14 having the gas vent hole 18,
The entire C element 14 is arranged on the annular portion 12. However, the opening position of the annular portion 12 of the inner lid 10 is aligned with the position of the gas vent hole 18 of the PTC element 14, and the area of the annular portion 12 and the gas vent hole 18 are provided. The area of the PTC element 14 may be the same.

The opening area of the annular portion 12 is 0.1 to 1.2 cm ² per battery capacity (Ah) from the viewpoint of allowing the decomposed gas generated in the outer can 1 to satisfactorily escape to the outside. It is desirable to set the range to. The valve membrane 11 is preferably a composite membrane in which a metal thin film such as Al and a synthetic resin thin film are laminated.

In the core space of the electrode body 2, a pipe made of metal such as stainless steel or plastic is allowed to be arranged for the purpose of preventing the core space that serves as a passage for the decomposition gas from being crushed. . The annular portion is not limited to the annular shape, and may have a shape matching the outer shape of the outer can 1, for example, a rectangular annular shape.

[0015]

The non-aqueous electrolyte battery according to the present invention has the inner lid 1
0 to match the opening position of the annular portion 12 and the position of the gas vent hole 18 of the PTC element 14, or the gas vent hole 1
The PTC element 14 can be satisfactorily operated because the sealing lid group 8 having the structure located inside the 8 position is attached to the outer can 1 through the insulating gasket 9.

That is, in the conventional non-aqueous electrolyte battery, as shown in FIG. 2, the opening position of the annular portion 32 of the inner lid 30 is P.
The area outside the gas vent hole 38 of the TC element 34, that is, the area of the annular portion 32 is much smaller than the area of the PTC element 34 having the gas vent hole 38.
Only the vicinity of the peripheral edge of the C element 34 is arranged on the annular portion 32. Therefore, the inner lid body 30, PT
When the sealing lid group 28 including the C element 34 and the like is caulked and fixed to the outer can 21 via the insulating gasket 29, the PTC element 34 disposed only on the peripheral portion above the annular portion 32 of the inner lid 30. Is locally pressed, and the characteristic of the PTC element 34 that its resistance value rapidly increases with a rise in temperature is impaired.

From the above, the opening position of the annular portion 12 of the inner lid 10 and the position of the gas vent hole 18 of the PTC element 14 are made to coincide with each other as in the present invention, or the inside of the gas vent hole 18 position. Then, the entire PTC element 14 is arranged on the annular portion 12, so that the sealing lid group 8 including the inner lid body 10, the PTC element 14 and the like can be packaged via the insulating gasket 9. When the caulking is performed on the inner lid 10, the annular portion 12 of the inner lid 10 is fixed.
As a result, the PTC element 14 arranged on the PTC element 14 can be prevented from being locally pressurized, and thus the characteristic that the resistance value rapidly increases with the temperature rise of the PTC element 14 can be favorably maintained. Therefore, even if a larger current than usual, for example, a large current is given due to an overcharged state, the PTC located between the inner lid 10 and the outer lid 15
Since the element 14 operates well and the resistance value sharply increases as the temperature rises and the current can be reliably cut off, it is possible to avoid a sharp increase in the internal pressure and prevent the battery from bursting.

The decomposed gas generated in the outer can 1 can satisfactorily pressurize and break the valve membrane 11 disposed on the inner lid 10 through the gas vent holes 16 of the inner lid 10. The decomposed gas is released from the valve membrane 11, the reinforcing plate 13, the PCT element 14 and the outer lid 15 through the gas vent holes 17, respectively.
It is possible to smoothly escape to the outside through 18 and 19, and it is possible to prevent the battery from exploding and igniting.

[0019]

Embodiments of the present invention will now be described in detail with reference to FIG. Example 1

A composite oxide of lithium and cobalt (LiC
A positive electrode mixture prepared by adding a conductive agent and a binder to oO ₂ ) was applied to an aluminum substrate and dried to prepare a sheet-shaped positive electrode. A negative electrode mixture prepared by adding a binder to a carbonaceous material supporting lithium was applied to a stainless steel substrate and dried to prepare a sheet-shaped negative electrode. A separator made of a polypropylene porous film is sandwiched between the sheet-shaped positive electrode and negative electrode to form a laminate, and the laminate has an outer diameter of 4 m.
m, inner diameter 2.11 mm, stainless steel pipe (opening area 0.0349 cm ² ) Was wound into a spiral shape to prepare an electrode body.

Next, the electrode body was housed in a stainless steel bottomed cylindrical outer can, and a mixed solvent of propylene carbonate and dimethoxyethane (volume ratio 50:50).
An electrolytic solution in which 1 mol / l of lithium phosphorofluorophosphate (LiPF ₆ ) was dissolved was housed in. Subsequently, the inner lid of the sealing lid group that also functions as an explosion-proof function and the positive electrode terminal and the positive electrode of the electrode body housed in the outer can are connected by a positive electrode lead, and the sealing lid group is connected to the upper end opening of the outer can. It has the structure shown in FIG. 1 (the core is not shown) by airtightly caulking and fixing it through an insulating gasket, and has an outer diameter of 17 mm and a total height of 50 m.
A cylindrical non-aqueous electrolyte battery having a m and a capacity of 750 mAh was assembled. In addition, the internal lid body 10 that constitutes the sealing lid group 8
The opening diameter of the annular portion 12 is 8 mm, and the diameter of the gas vent hole 18 of the PTC element 14 arranged on the annular portion 12 is
8.9 mm, and the opening position of the annular portion 12 is P
Inside the gas vent hole 18 of the TC element 14,
The entire TC element 14 is arranged on the annular portion 12. Comparative Example 1

The opening diameter of the annular portion of the inner lid body constituting the sealing lid group is 13.8 mm, and P is arranged on the annular portion.
The diameter of the gas vent hole of the TC element is 8.9 mm, and the PT
A cylindrical non-aqueous electrolyte battery having the same configuration as in Example 1 was assembled except that only the vicinity of the peripheral edge of the C element was arranged on the annular portion.

Batteries 2 obtained in Example 1 and Comparative Example 1
0.5A, 1.5A, 2A and 3.5 for 5
An overcharge test was conducted in which the current of A was applied for 24 hours, and the number of ruptured batteries was examined. The results are shown in Table 1 below. Table 1 0.5A 1.5A 2A 3.5A Example 1 0/25 0/25 0/25 0/25 Comparative Example 1 0/25 1/25 2/25 7/25

As is apparent from Table 1, the battery of Example 1 has higher safety than the battery of Comparative Example 1. In particular, it can be seen that the battery of Example 1 has excellent safety when the current during overcharge is high.

In addition, although the example applied to the cylindrical non-aqueous electrolyte battery has been described in the above embodiment, the present invention is also applicable to the non-aqueous electrolyte battery having various shapes such as a coin shape, a prismatic shape and an elliptical shape. You can

[0026]

As described above in detail, according to the present invention, the PTC element can be satisfactorily operated by eliminating the local pressure applied to the PTC element constituting the sealing lid group, and can be operated at the time of overcharge or short circuit. It is possible to provide a non-aqueous electrolyte battery capable of ensuring the safety of the above.

[Brief description of drawings]

FIG. 1 is a sectional view showing a cylindrical non-aqueous electrolyte battery according to the present invention.

FIG. 2 is a cross-sectional view showing a conventional cylindrical non-aqueous electrolyte battery.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer can, 2 ... Electrode body, 3 ... Positive electrode, 5 ... Negative electrode, 8 ... Sealing lid group, 9 ... Insulating gasket, 10 ... Internal electrode, 11 ... Valve membrane, 12 ... Annular part, 14 ...
PTC element, 15 ... External lid, 16, 17, 18, 19
… Venting holes.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyoshi Nose 3-4-10 Minami-Shinagawa, Shinagawa-ku, Tokyo Toshiba Battery Co., Ltd. No. Asahi Kasei Kogyo Co., Ltd. (72) Inventor Katsuhiko Inoue 1-3-1 Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa Asahi Kasei Kogyo Co., Ltd.

Claims (1)

[Claims] 1. An outer can, an electrode body housed in the outer can, in which a positive electrode, a separator and a negative electrode are spirally wound, a non-aqueous electrolyte contained in the outer can, and the outer can. A sealing lid group that also functions as a terminal and has an explosion-proof function that is airtightly caulked and fixed by an insulating gasket to an upper end opening of the sealing lid group, the sealing lid group being arranged to face the electrode body, and the internal lid A reinforcing plate disposed on the lid body through a valve membrane and sandwiched by an annular portion formed by bending the inner lid peripheral edge inward; a PTC element arranged on the annular portion of the inner lid body; Non-water composed of an outer lid body having a peripheral portion abuttingly arranged on the PTC element, and a gas vent hole formed in each of the inner lid body, the reinforcing plate, the PTC element and the outer lid body. In the electrolytic solution battery, the inner lid Wherein either match the venting hole positions, or a non-aqueous electrolyte battery characterized by being inward of the gas release openings of said PTC element an opening position of said annular portion.