JP3290226B2 - Non-aqueous electrolyte battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

In the above-described secondary battery, an electrode body having a positive electrode and a negative electrode housed in an outer can may undergo a chemical change to increase the internal pressure and cause a burst.
For example, a non-aqueous electrolyte battery such as a lithium secondary battery is supplied with a current higher than usual, or in a so-called overcharged state,
If a short circuit occurs due to misuse and a large current flows, the non-aqueous electrolyte in the electrode body may be decomposed to generate gas. Such a gas gradually fills the outer can, and when the internal pressure in the outer can increases, the battery eventually bursts.

For this reason, a non-aqueous electrolyte battery having an explosion-proof function and a sealing lid group having a terminal as shown in FIG. 5 is conventionally known in order to prevent the battery from being ruptured. . That is, the electrode body 22 is housed in the bottomed cylindrical outer can 21 also serving as the negative electrode terminal. The electrode body 22 includes a positive electrode 23, a separator 24, and a negative electrode 25.
Is wound spirally. The group of sealing lids 26 which also has an explosion-proof function and a terminal
Is caulked and fixed to the upper end opening via an insulating gasket 27.

The sealing lid group 26 includes an intermediate lid 30 having a downwardly projecting portion 28 at the center and a downwardly extending annular projecting portion 29 formed outside the projecting portion 28. The plurality of linear grooves 31 are formed radially on the upper surface of the intermediate cover 30 located between the protrusion 28 and the annular protrusion 29. The bottom of the linear groove 31 functions as a valve membrane. The peripheral portion of the hat-shaped closing lid 33 having the gas vent hole 32 is disposed on the intermediate lid 30, and the closing lid 33 is clamped by the intermediate lid 30 by bending the peripheral edge of the intermediate lid 30 inward. Have been. The peripheral edges of the intermediate lid 30 and the closing lid 33 are air-tightly fixed to the upper end opening of the outer can 21 via the insulating gasket 27. A lead stopper 34 made of a bottomed cylindrical insulating material is fitted to the annular projection 29 of the intermediate cover 30. The lead stopper 3
An insertion hole 35 into which the protruding portion 28 of the intermediate lid 30 is inserted is opened at the center of 4. Multiple vent holes 3
6 is formed in the lead stopper 34 concentrically around the insertion hole 35. Positive electrode lead plate 37
Is mounted on the back surface of the lead stopper 34 so as to cover at least the insertion hole 35, and the projection 28 of the intermediate lid 30 inserted into the insertion hole 35 is connected by welding. The positive electrode lead 38 has one end connected to the positive electrode 23 of the electrode body and the other end connected to the positive electrode lead plate 37. Therefore, the electrode body 2
The positive electrode 23 is composed of the positive electrode lead 38 and the positive electrode lead plate 3.
7. Connected to the closing lid 33 via the projection 28 of the intermediate lid 30 welded to the positive electrode lead plate 37 through the insertion hole 35 of the lead stopper 34.

In the non-aqueous electrolyte battery having such a configuration, when a current higher than normal, for example, a large current is applied due to an overcharged state and a decomposition gas is generated by the large current, the decomposition gas is discharged from the lead stopper 34. Gas vent hole 36
Through the space between the lead stopper 34 and the intermediate lid 30 to increase the internal pressure. As a result, the intermediate lid 30 is pressed toward the closing lid 33 by the internal pressure, so that the intermediate lid 3 welded to the positive electrode lead plate 37 through the insertion hole 35 of the lead stopper 34.
The 0 projection 28 is disengaged and the current path of the positive electrode is cut off. Further, the valve membrane corresponding to the plurality of linear grooves 31 of the intermediate lid 30 is broken by the internal pressure, and the decomposed gas passes through the gas vent hole 32 opened in the break point of the valve membrane and the closing lid 33. Escape to. Therefore, the battery is prevented from being ruptured due to the current interruption and the escape of the decomposition gas to the outside of the battery.

However, in the above-described conventional non-aqueous electrolyte battery provided with the sealing lid group 26 which also functions as an explosion-proof function and a terminal, the projection 28 of the intermediate lid 30 which comes off from the positive electrode lead plate 37 with the rise of the internal pressure. Is exposed to the atmosphere of the flammable decomposition gas, so that the positive electrode lead plate 37
Therefore, there is a problem that the decomposition gas is ignited with the occurrence of spark when the projection 28 comes off.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent rupture due to a sudden increase in internal pressure that occurs at the time of overcharge or short circuit, and to prevent flammable decomposition gas generated from igniting when current is cut off. It is an object of the present invention to provide a non-aqueous electrolyte battery capable of performing the above-described steps.

[0009]

A non-aqueous electrolyte battery according to the present invention comprises an outer can, a positive electrode,
An electrode body comprising a separator and a negative electrode, a non-aqueous electrolyte contained in the outer can, and a sealing lid group serving also as an explosion-proof function and a terminal air-tightly secured by an insulating gasket at an upper end opening of the outer can. In the non-aqueous electrolyte battery comprising: the sealing lid group, an inner lid body having a vent hole disposed opposite the electrode body, a valve membrane disposed on the inner lid body, the valve membrane An inner insulating packing layer having a vent hole disposed on the inner lid body, and a peripheral portion is disposed on the packing layer, and the inner lid peripheral edge and the peripheral edge portion of the packing layer are respectively provided inside. A hat-shaped outer lid having a gas vent hole sandwiched by a bent annular portion, one end of which is sandwiched between the inner lid and the packing layer, and the other end of the packing layer. It is characterized in that through the scan drain hole and a current interruption leads sandwiched extending between the outer lid and the packing layer.

Hereinafter, a non-aqueous electrolyte battery according to the present invention will be described in detail with reference to FIGS.

For example, an electrode body 2 is housed in a bottomed cylindrical outer can 1 also serving as a negative electrode terminal. The electrode body 2
Has a configuration in which a laminate of the positive electrode 3, the separator 4, and the negative electrode 5 is spirally wound.

A group of sealing lids 6 having both an explosion-proof function and a terminal
Is caulked and fixed to the upper end opening of the outer can 1 via an insulating gasket 7. The sealing lid group 6 includes a dish-shaped inner lid 9 having a large-diameter vent hole 8 near the center, which is disposed to face the electrode body 2. A valve membrane 10 formed of a flexible thin film is disposed on the inner lid 9. A large-diameter vent hole 11 near the center
The inner insulating packing layer 12 having the following structure is disposed on the inner lid 9 including the valve membrane 10. Gas vent hole 1
The outer peripheral portion of the hat-shaped outer cover 14 having the peripheral portion 3 is disposed on the packing layer 12, and the outer peripheral portion 14 has a peripheral rising portion of the internal lid 9 and a peripheral rising portion of the packing layer 12. Each is held by an annular portion bent inward. The annular portion is caulked and fixed to the outer can 1 by the insulating gasket 7. One end of the band-shaped current interrupting lead 15 is sandwiched between the inner lid 9 and the packing layer 12, and the other end thereof is the gas vent hole 11 of the packing layer 12.
Extends between the packing layer 12 and the outer lid 14 and is sandwiched. The current interruption lead 15
For example, as shown in FIG. 2, a cutout portion 16 is formed in the width direction, and the current interrupting lead 15 is arranged so that the cutout portion 16 is located above the center of the gas vent hole 8 of the internal lid 9. Have been. A holding plate 18 having a plurality of gas vent holes 17 is arranged on the electrode body 2. One end of the positive electrode lead 19 is connected to the positive electrode 3 of the electrode body 2 through the peripheral cutout of the holding plate 18, and the other end is connected to the lower surface of the inner lid 9 of the sealing lid group 6. Therefore, the positive electrode 3 of the electrode body 2 is connected to the outer lid 14 through the positive electrode lead 19, the inner lid 9, and the current blocking lead 15.

As the valve film 10, it is preferable to use a composite film in which a thin film of a metal such as Al and a thin film of a synthetic resin are laminated.

The current interrupting lead 15 has a slit at the center from one end to the other end of the strip-shaped metal plate as shown in FIG.
A current interrupting lead 15 ′ may be used in which one of the two pieces separated left and right about the slit is bent 180 ° and the piece extends in the opposite direction at the rising joint 20. .

As shown in FIG. 1, when the laminate of the positive electrode 3, the separator 4, and the negative electrode 5 is spirally wound to form the electrode body 2, a flow path of the decomposition gas is formed in the core space. A pipe made of a metal such as stainless steel or a plastic is allowed for the purpose of preventing the core space from being crushed.

[0016]

The non-aqueous electrolyte battery according to the present invention has an inner lid 9 having a vent hole 8, a valve membrane 10, an inner insulating packing layer 12 having a vent hole 11, and an outer lid 14 having a vent hole 13. And one end is sandwiched between the inner lid 9 and the packing layer 12, and the other end is inserted through the vent hole 11 of the packing layer 12.
A sealing lid group 6 having a band-shaped current interrupting lead 15 extending and sandwiched between the outer lid 14 and the outer lid 14 is attached to the outer can 1 via an insulating gasket 7.

In the non-aqueous electrolyte battery having such a configuration, when a current higher than normal, for example, a large current is applied due to an overcharged state, and a decomposition gas is generated in the outer can 1 to increase the internal pressure, the internal pressure increases. Is the gas vent hole 8 of the inner lid 9
Through to the central portion of the leaflet 10 above it. Since the peripheral edge of the valve membrane 10 is sandwiched between the inner lid 9 and the packing layer 12, when the internal pressure reaches a predetermined value, as shown in FIG. , The valve membrane 10 corresponding to the above is pushed upward, and the current interrupting lead 15 arranged above the valve membrane 10 is similarly pushed upward. For example, as shown in FIG. 2, the current interrupting lead 15 has a cutout 16 formed in the width direction thereof, and the cutout 16 is positioned so as to face the center of the gas vent hole 8 of the internal lid 9. Therefore, when the stress limit of the cut-off portion 16 of the current cut-off lead 15 is exceeded by the pushing up by the valve membrane 10, the current cut-off lead 15 is broken at that portion and the current path of the positive electrode is cut off. When the current interrupting lead 15 'having the shape shown in FIG.
When the stress limit for zero is exceeded, the piece is cut off, and the two pieces extending in the opposite direction from the joint 20 are separated, and the current path of the positive electrode is cut off.

The current interruption lead 15 is connected to the valve membrane 10.
Therefore, since the flammable decomposed gas is isolated from the atmosphere where the decomposed gas is generated, even if a spark is generated when the current interruption lead 15 is broken, it is possible to prevent ignition caused by the presence of the decomposed gas around the spark. .

Further, when the internal pressure further rises, the valve membrane 10 itself is broken, so that the decomposed gas flows to the outside through the rupture point of the valve membrane 10 and the gas vent hole 13 opened in the external lid 14. Escape smoothly.

Therefore, the battery can be prevented from being ruptured due to the interruption of the current and the escape of the decomposition gas to the outside of the battery.
Moreover, it is possible to prevent ignition of the generated combustible decomposition gas at the time of current interruption.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to FIGS.
This will be described in detail with reference to FIG.

Example 1 A positive electrode mixture prepared by adding a conductive agent and a binder to a composite oxide of lithium and cobalt (LiCoO ₂ ) was applied to an aluminum substrate and dried to prepare a sheet-shaped positive electrode.
A negative electrode mixture obtained by adding a binder to a carbonaceous material carrying lithium was applied to a stainless steel substrate and dried to produce a sheet-shaped negative electrode. An electrode body was manufactured by spirally winding a separator made of a porous film made of polypropylene between the sheet-like positive electrode and the negative electrode.

Next, the electrode body was housed in a stainless steel bottomed cylindrical outer can, and propylene carbonate and γ
Mixed solvent with -butyl lactone (volume ratio 50:50)
An electrolyte solution in which lithium tetrafluoroborate (LiBF ₄ ) was dissolved was stored. Subsequently, the inner lid of the sealing lid group also serving as an explosion-proof function and a positive electrode terminal and the positive electrode of the electrode body housed in the outer can are connected with a positive electrode lead, and the sealing lid group is connected to the upper end opening of the outer can. A cylindrical non-aqueous electrolyte battery having an outer diameter of 18 mm, a total height of 50 mm, and a capacity of 750 mAh having the structure shown in FIG. 1 was secured by airtightly caulking via an insulating gasket. Note that the current blocking lead 15 constituting the sealing lid group had a cutout 16 formed in the width direction shown in FIG.

Example 2 A cylindrical nonaqueous electrolyte battery similar to that of Example 1 was assembled except that the electrode lead 15 'having the shape shown in FIG. 3 was used.

Each of the obtained cylindrical non-aqueous electrolyte batteries of Examples 1 and 2 and the conventional cylindrical non-aqueous electrolyte battery (conventional example) shown in FIG. 5 were prepared. The number of overcharged and ignited batteries was checked under the following conditions. The results are shown in Table 1 below.

Table 1 Charging conditions Number of ignited batteries Example 1 10C, 10V 0/100 Example 2 10C, 10V 0/100 Conventional example 10C, 10V 3/100 Also, batteries of Examples 1, 2 and the conventional example The average value of the current interruption reaching time when overcharging was performed under the conditions of 3 C and 10 V was measured for 20 pieces. The results are shown in Table 2 below.

Table 2 Charging conditions Average time to reach current interruption Example 1 3C, 10V about 37 seconds Example 2 3C, 10V about 34 seconds Conventional example 3C, 10V about 42 seconds As is clear from Table 1, Example 1, It can be seen that the battery No. 2 can reliably prevent ignition at the time of current interruption.
As is clear from Table 2, the current interrupting lead having the shape shown in FIG.
It can be seen that the breaking time is shorter than the current breaking lead having the shape shown in FIG.

In the above embodiment, a non-aqueous electrolyte battery incorporating a spirally wound electrode body has been described, but the electrode body may be formed by laminating a positive electrode, a separator and a negative electrode.

In the above embodiment, an example in which the present invention is applied to a cylindrical non-aqueous electrolyte battery is described. However, the present invention can be similarly applied to non-aqueous electrolyte batteries having various shapes such as a coin shape, a square shape, and an elliptical shape. it can.

[0030]

As described in detail above, it is possible to prevent a rupture due to a sudden increase in internal pressure that occurs at the time of overcharging or short circuit.
It is possible to provide an extremely safe nonaqueous electrolyte battery that can prevent ignition of generated combustible decomposition gas when current is interrupted.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a cylindrical nonaqueous electrolyte battery according to the present invention.

FIG. 2 is a perspective view showing a current interrupting lead incorporated in the battery of FIG. 1;

FIG. 3 is a perspective view showing another embodiment of the current interrupting lead.

FIG. 4 is an essential part cross-sectional view for explaining the operation of the battery in FIG. 1;

FIG. 5 is a sectional view of a main part showing a conventional cylindrical nonaqueous electrolyte battery.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer can, 2 ... Electrode body, 3 ... Positive electrode, 5 ... Negative electrode, 6 ... Sealing lid group, 7 ... Insulating gasket, 9 ... Internal electrode, 10 ... Valve membrane, 12 ... Inner insulating packing layer, 14 ... Outer lid , 1
5, 15 ': current interruption lead, 19: positive electrode lead.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoji Ishihara 3-4-10 Minamishinagawa, Shinagawa-ku, Tokyo Toshiba Battery Corporation (72) Inventor Yoshiaki Azumi 3-4-1 Minamishinagawa, Shinagawa-ku, Tokyo No. Toshiba Battery Co., Ltd. No. Asahi Kasei Kogyo Co., Ltd. (72) Inventor Katsuhiko Inoue 1-3-1, Yakko, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Asahi Kasei Kogyo Co., Ltd. (56) References JP-A-2-207450 (JP, A) JP-A Heisei JP-A-5-159762 (JP, A) JP-A-4-112459 (JP, U) JP-A-6-15260 (JP, U) JP-A-2-56349 (JP, A) U) Hira 4-24262 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 2/34 H01M 2/04 H01M 2/12 101 H01M 10/40

Claims (1)

(57) [Claims] 1. An outer can, an electrode body housed in the outer can, comprising a positive electrode, a separator and a negative electrode, a non-aqueous electrolyte housed in the outer can, and an upper end opening of the outer can. In a non-aqueous electrolyte battery including an explosion-proof function and a sealing lid group serving also as a terminal, which are hermetically fixed by an insulating gasket, the sealing lid group has a gas vent hole arranged to face the electrode body. An inner lid, a valve membrane disposed on the inner lid, an inner insulating packing layer having a vent hole disposed on the inner lid including the valve membrane, and a peripheral portion on the packing layer. A hat-shaped outer lid having a gas vent hole, which is disposed and sandwiched by annular portions formed by bending the inner lid peripheral edge and the peripheral edge of the packing layer inward, respectively, and one end having the inner lid and the inner lid. Pa A non-aqueous current supply lead interposed between the king layer and the other end extending between the packing layer and the outer lid through the gas vent hole of the packing layer and interposed therebetween. Electrolyte battery.