JPH097571A - External containers such as batteries - Google Patents

Abstract

(57) [Summary] [Object] To provide an outer container for a battery or the like, which can securely join the outer container and the safety valve in a short time and which can use an inexpensive processing means. [Structure] A projecting opening edge portion 3 is formed by projecting an opening edge portion of a hole portion 2a formed in an outer container body or a lid body of the outer container body, and a safety valve is formed on the projecting opening edge portion 3. The outer peripheral edge of No. 1 is abutted, and the pair of welding electrodes 4 and 5 are pressed and urged so as to sandwich the safety valve 1 and the outer container 2 to perform resistance welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer container such as a battery having an explosion-proof function for preventing the outer container from exploding when the internal pressure of the battery or the like rises due to some abnormality.

[0002]

2. Description of the Related Art Conventionally, various pressure release safety valves have been proposed in which the valve body releases pressure when the internal pressure of a battery or the like rises due to a circuit abnormality or the like to prevent the battery outer container from exploding. ing. For example, a non-aqueous secondary battery using a lithium composite oxide as a positive electrode active material (JP-A-55-13).
No. 6131), a non-aqueous secondary battery using a lithium composite oxide as a positive electrode active material and a carbonaceous material as a negative electrode active material (JP-A-62-90863, JP-A-63-299056).
No.), etc., but the internal pressure of the battery does not almost rise during normal use, but the performance of the battery gradually decreases when the bipolar active material, electrolyte, etc. react with water, oxygen, etc. Therefore, in this type of battery, a safety valve that can be opened and closed is unsuitable, and it is preferable to have a completely sealed structure.

However, in a completely sealed battery,
Although the airtightness is improved and the storage is excellent, under abnormal conditions such as when it is heated to a high temperature or when it is charged with a high voltage or a large current, the internal pressure of the battery rises, resulting in the battery outer container Since it may rupture and the contents may scatter and cause personal or property damage, make sure that the internal pressure of the battery does not exceed the limit pressure resistance of the battery outer container or the battery sealing part to cause an explosion. Various proposals have been made in which a thin wall portion formed of a groove is provided in a part of a container and the pressure is released by breaking the thin wall portion.

That is, a mechanism for providing a cross-shaped thin portion in the container of a sealed alkaline button battery (controlling the wall thickness at the intersection thereof (No. 58-17332), a flat portion is formed at the bottom of the battery outer container, and A mechanism for forming a groove having an intersection at the center of the ridge (JP-A-63-86244 and JP-A-63-86).
No. 246) A mechanism for forming a thin portion on the inner surface of the bottom of the battery outer container (JP-A-63-86245), and a mechanism for forming a linear thin portion branched at both ends on the bottom of the battery outer container (JP-A-1). No. 309252, JP-A-1-309253
No.), and a mechanism for disposing a safety valve made of stainless steel in which a thin portion that breaks at a predetermined pressure and releases the pressure is formed in a hole portion of an outer container.

Since the mechanism for disposing the safety valve in the hole of the outer container separates the battery outer container and the safety valve,
This has the advantage that suitable materials can be separately set for the outer container and the safety valve.

[0006]

However, in order to join the safety valve to the battery outer container, a means for laser welding the outer peripheral edge of the safety valve covering the hole of the battery outer container is currently used. The laser welding machine is expensive and expensive to process, and since the spot welding is performed around the outer periphery of the safety valve, it takes a long time to join the safety valve. Further, in a lithium-ion secondary battery having an outer container as a positive electrode, the outer container and the safety valve are often made of aluminum or an aluminum alloy, but aluminum is thinner than stainless steel because of its strength. In addition to being thick and having a low melting point, it is difficult to control the output of laser welding, and since aluminum has good thermal conductivity and heating by a laser can easily escape, it was extremely difficult to perform laser welding.

Therefore, in the present invention, the outer container and the safety valve can be reliably joined in a short time, and
It is intended to provide an outer container such as a battery which can use an inexpensive processing means.

[0008]

In order to achieve the above-mentioned object, an outer container of a battery or the like according to the present invention has an opening edge portion of a hole formed in the outer container of the battery or the like and a protruding opening edge portion. A safety valve is formed on the projecting opening edge portion of which the thin wall portion is broken by a predetermined pressure, and the outer container and the safety valve are resistance-welded by being pressed by a pair of welding electrodes. It is characterized by becoming.

Alternatively, a safety valve whose thin portion is broken by a predetermined pressure is covered in a hole formed in an outer container such as a battery, and the outer surface of the safety valve faces the periphery of the hole of the outer container. It is characterized in that a reinforcing ring formed with a convex portion is brought into contact, and the outer container, the safety valve and the reinforcing ring are pressed and biased by a pair of welding electrodes and resistance welded.

Resistance welding may be performed by interposing a reinforcing ring between the welding electrode and the welding portion of the safety valve.

Alternatively, a lid is placed in the opening of an outer container such as a battery made of a cylindrical body, and a first welding electrode having a circular shape is provided on the outer peripheral edge of the lid, and the outer container. The lid is resistance-welded to the outer container by a second welding electrode that closely surrounds the outer container and surrounds the outer container.

Alternatively, an electrode pin having a brim on a columnar body that is inserted insulatively into a hole formed in an outer container such as a battery, and a hollow that covers the tip of the columnar body through which the electrode pin is inserted. The inverted frustoconical cap body is caulked to hermetically seal the hole of the outer container.

A lead tab may be interposed between the electrode pin and the cap body for caulking.

[0014]

The opening edge portion of the hole formed in the outer container such as a battery is projected to form a protruding opening edge portion, and the protruding opening edge portion is covered with a safety valve whose thin portion is broken by a predetermined pressure. The lid and the safety container and the safety valve are pressed and urged by a pair of welding electrodes to be resistance-welded, so that the electric current concentrates on the line contact portion between the projecting opening edge of the hole of the exterior container and the safety valve. By emitting high heat, the safety valve covers the hole of the outer container and is welded instantly and reliably.

The hole formed in the outer container such as a battery is covered with a safety valve whose thin portion is broken by a predetermined pressure.
On the outer surface of the safety valve, a reinforcing ring formed by forming a convex portion toward the periphery of the hole of the outer container is contacted, and the outer container, the safety valve and the reinforcing ring are pressed and biased by a pair of welding electrodes. Resistance welding, the electric current of resistance welding is concentrated on the line contact part between the safety valve and the convex part of the reinforcing ring to generate high heat, and this high heat is also transmitted around the hole of the outer container, Is pressed and urged by the welding electrode, the safety valve is instantaneously and reliably resistance-welded while the hole of the outer container is covered and sandwiched between the outer container and the reinforcing ring, and By overlapping, the heat of welding is suitably transmitted to the outer container and the safety valve, and the welded portion is mechanically reinforced, so that a suitable joined state can be obtained.

When resistance welding is performed by interposing a reinforcing ring between the welding electrode and the welding portion of the safety valve, the safety valve is generally thinner than the outer container, and the high heat during welding is easily reinforced to escape to the outer container. By stacking the rings, the heat of welding is suitably transmitted to the outer container and the safety valve, and the welded portion is mechanically reinforced, so that a suitable joined state can be obtained.

Alternatively, a lid is placed on an opening of an outer container such as a battery made of a cylindrical body, and a first welding electrode having a circular shape is provided on an outer peripheral edge of the lid, and the outer container. Even if the electrode body or the like is housed in the outer container by resistance welding the lid to the outer container by a second welding electrode that closely surrounds the outer container and surrounds the outer container. It becomes possible to resistance-weld the lid to the.

[0018]

1 shows a state in which a first embodiment of an outer container for a battery or the like according to the present invention is welded, and FIG. 2 shows an outer container for a battery or the like welded by this. In the figure, reference numeral 1 denotes a thickness of 0. 1 provided with a thin portion (not shown) that is broken at a predetermined pressure.
A safety valve made of stainless steel having a thickness of about 02 to 0.2 mm, or aluminum having a thickness of about 0.1 to 0.4 mm, 2 is stainless steel or aluminum which is a battery outer container body or a lid for covering the outer container body. The outer container 3 made of, for example, is a protruding opening edge portion formed by protruding the opening edge portion of the hole 2a having a perfect circle, an oval shape, or an elliptical shape penetrating the outer container 2. Reference numerals 4 and 5 are welding electrodes for resistance welding. The welding electrode 4 on the side contacting the safety valve 1 has a flat surface, whereas the welding electrode 5 on the side contacting the outer container 2 has a hole 2a. By providing the convex portion 5a that engages with, the protruding opening edge portion 3 can be surely pressed in the vertical direction without being deformed.

The safety valve 1 is provided with a convex portion 1a which engages with the hole 2a of the outer container 2 and a collar edge 1b with which the protruding opening edge portion 3 abuts on the outer periphery. Protruding opening edge 3
Can be integrally formed by press working when forming a hole in the outer container 2, or can be formed by subjecting the formed hole to a drawing process or a burring process. The height of the protruding opening edge portion 3 is set to about 0.2 to 1 mm, and in order to obtain a uniform joint state with the safety valve 1, it is preferable that there is no step on the ring periphery at the tip thereof and the width is uniform.

FIG. 3 is a second view of an outer container such as a battery of the present invention.
4 shows the state of being welded, and FIG. 4 shows the outer container of the battery or the like welded thereby. This outer container 2 is intended to achieve a good joint state with the safety valve 1 by cutting the inner peripheral portion of the protruding opening edge portion 3 in the first embodiment described above by cutting the C surface to make the tip sharp. The safety valve 1
A concave groove 1c is provided around the upper surface portion of the outer container 2 corresponding to the protruding opening edge portion 3. Further, the welding electrode 4 on the side in contact with the safety valve 1 is provided with a recess 4a for closely pressing and urging the bottom surface and the periphery of the safety valve 1 around which the recessed groove 1c is provided.

FIG. 5 shows another ridge used in the outer container of the battery or the like of the present invention, and the protruding opening edge portion 3 has the above-mentioned first ridge.
In this embodiment, the tip portion of the protruding opening edge portion 3 of the outer container 2 is bent in the inner peripheral direction. FIG. 6 shows another safety valve used in the outer container of the battery or the like of the present invention. This safety valve 1 is formed by raising the outer peripheral edge of a flat plate and forming a peripheral wall 1d which engages with the outer periphery of the protruding opening edge portion 3. . FIG. 7 shows still another safety valve, which has a flat plate having an outer peripheral edge of 2
It is a heavy fold, and the protruding opening edge portion 3 of the outer container 2 is brought into contact with the double portion 1e and welded. This is because the outer container 2 having a plate thickness of about 0.2 to 1 mm and the plate thickness of 0.02
When welding the safety valve 1 of about 0.2 mm,
The heat of welding easily escapes from the thin safety valve 1 to the thick outer container 2 and the welding electrode 4, and when the heat of welding becomes excessive, the thin safety valve 1 melts and a suitable joining state cannot be obtained. By making the joint portion of 1 thick, the heat of welding is suitably transmitted to the outer container 2 and the safety valve 1,
This is so that a suitable joining state can be obtained.

In the outer container such as the battery of the present invention having the above structure, the convex portion 1 of the safety valve 1 is used in the first embodiment.
a is engaged with the hole 2a of the outer container 2, the outer peripheral edge 1b is brought into contact with the protruding opening edge portion 3 of the outer container 2, and in the second embodiment, the concave groove 1d of the safety valve 1 is protruded from the outer container 2. Opening edge 3
To be engaged. Then, while the welding electrodes 4 and 5 are pressed and urged so as to sandwich the safety valve 1 and the outer container 2, a large current is passed between the welding electrodes 4 and 5, whereby the protruding opening edge portion 3 is formed.
The tip and the portion of the safety valve 1 that comes into contact therewith become hot and melt, and the safety valve 1 is resistance-welded to the outer container 2.

The welding conditions for this resistance welding vary depending on the heat capacity in the vicinity of the welded portion, that is, the material, shape, size, etc. of the safety valve, the outer container and the ridges, but the current linear density is approximately 1 to 50 kA / cm. Pressure linear density is 50-50
The welding current is about 0 kgf / cm, and alternating current, direct current (1 pulse), or direct current (a plurality of pulses) using an inverter can be appropriately used as the welding current. In the case of exchange,
In addition to frequency and amplitude, the energization time is controlled to vary the amount of current, and in the case of direct current (1 pulse), the amount of current is varied according to the peak current value and pulse width, and to the direct current (multiple pulses) using an inverter. In that case, in addition to the peak current value and the pulse width, the current amount can be changed by the frequency and the number of pulses. If a large current is required as the welding current, an alternating current is often used. Each of these resistance welding machines is an inexpensive device as compared with the laser processing machine.

FIG. 8 shows a third embodiment of the present invention. For a cylindrical battery, for example, when the outer container is a negative electrode,
A cylindrical pipe made of 2 to 0.5 mm SUS304 or nickel-plated iron (SPC) or the like (aluminum or the like when the outer container is a positive electrode) is cut to a predetermined length, and the lower end is drawn. The outer casing 2 of the battery is provided with the projecting opening edge 3 around the hole 2a, and the cylindrical welding electrode 5 is inserted into the outer casing 2 and set in the welding apparatus. Then, the safety valve 1 having a plate thickness of about 0.05 mm with the convex portion 1a as shown in FIG.
The welding electrode 4, with the outer peripheral edge 1b of the safety valve 1 in contact with the protruding opening edge 3 of the outer container 2,
5 presses and urges the safety valve 1 and the periphery of the hole 2a so that a large current is passed between the welding electrodes 4 and 5. This allows
The safety valve 1 is resistance welded to the protruding opening edge 3.

FIG. 9 shows the safety valve 1 and the welding electrode 4 shown in FIG.
And the step portion 6a on the outer peripheral edge so as to engage with the outer periphery of the safety valve 1.
The 4th example of the present invention which interposes the reinforcement ring 6 which formed is shown. The reinforcing ring 6 has a plate thickness of approximately 0.2 to 0.5 mm, which is substantially the same as that of the outer container 2, and thus is substantially the same as the thickness of the welded portion of the safety valve 1 in the embodiment of FIG. 7 described above. The effect is exhibited, the heat of welding is suitably transmitted to the outer container 2 and the safety valve 1, and the welded portion is mechanically reinforced, so that a suitable joined state is obtained.

FIG. 10 shows another embodiment of the reinforcing ring 6 in the embodiment shown in FIG. 9, and FIG. 10 (a) shows that the safety valve 1 is provided in the hole 2a of the flat outer container 2, and A reinforcing ring 6 having a convex portion 6b having a triangular cross section formed on the upper surface of the ring body is disposed below. In this case, no protrusion is required around the hole 2a of the outer container 2, and the convex portion 6b of the reinforcing ring 6 serves as a substitute. Figure 10 (b)
Is a reinforcing ring 6 having a triangular cross section, and FIG.
Has a circular cross section, and FIG. 10D has a semicircular cross section, both of which have a shape protruding toward the safety valve. The convex portion 6b or the protruding portion of the reinforcing ring 6 exhibits the same function and effect as the protruding opening edge portion 3 in the above-described first to fourth embodiments, and the line contact portion between the safety valve and the reinforcing ring. The electric current of resistance welding is concentrated on and generates high heat.

In the above-mentioned third and fourth embodiments, the structure in which the safety valve is arranged in the hole portion of the outer container has been described, but this welding method is applied to cover the outer container instead of the safety valve. 11 and 12 show a fifth embodiment of the present invention in which the above is provided. This is related to the cylindrical battery as in the third embodiment, for example, when the outer container is a negative electrode, SUS304 of 0.2 to 0.5 mm, or SPC.
A tubular pipe made of, for example, aluminum (or the like when the outer casing is a positive electrode) is cut into a predetermined length, and one end of the pipe is used as the protruding opening edge portion 3 to form the outer casing 2. Then, as shown in FIG. 12, at one end of the outer container 2, a lid body 8 having an electrode terminal 7 arranged in advance and provided with a step portion 8a engaging with the inner periphery of the outer container 2 on the outer periphery is placed. The first welding electrode 9 having a circular shape contacts from above, and the second welding electrode 10 having a ring shape that closely surrounds the outer periphery of the upper end portion of the outer container 2 contacts. In this state, the lid 8 is resistance-welded to the protruding opening edge portion 3 of the outer container 2 by passing a large current between the welding electrodes.

In the welding methods of the third and fourth embodiments described above, it is necessary to fit the welding electrode in the outer container, so that after the electrode body and the like are housed in the outer container 2, Although not applicable, the welding method according to the fifth embodiment enables the lid 8 to be welded to the outer container 2 in any assembled state.

The electrode terminal 7 will be described in detail with reference to FIG.
As shown in FIG. 1, the electrode pin 12 integrated with the insulating spacer member 11 is inserted through the washer and the like (not shown) together with the hole portion of the lid body 8, and the tip of the electrode pin 12 is made of the same material as the electrode pin 12 and is hollow. Reverse frustoconical cap body 13
Then, the cap body 13 and the electrode pin 12 are caulked, and the hole of the lid body 8 is sealed. The cap body 13 has a plate thickness of about 0.3 mm (when the material is SPC)
It can be produced by spinning or drawing a round plate material of No. 3, which greatly contributes to the reduction of manufacturing cost as compared with the cutting work of Muku material.

Although not particularly shown, in the fifth embodiment described above, the electrode pin 12 inserted through the hole of the lid 8 is inserted.
However, the lead tab for external connection is inserted together with the washer, and the cap body 13 is put over the lead tab to cover the cap body 13.
The electrode pin 12 may be caulked to seal the hole of the lid 8.

[0031]

As described above in detail, according to the outer container of the present invention such as the battery, the safety valve and the outer container are resistance-welded in a line contact state by forming the protruding opening edge portion in the hole, By concentrating the electric current on the line contact portion, the safety valve and the outer container are instantly and reliably welded. As a result, the safety valve can be joined to the battery outer container in a sealed state in a short time, and the processing cost can be reduced by using an inexpensive resistance welding machine without using an expensive laser processing machine. Is something that can be done. Also, in the case of the aluminum outer container and the safety valve, it was extremely difficult to obtain good joining with the conventional laser welding machine, but by resistance welding using the outer container such as the battery of the present invention, It became possible to reliably bond in a short time.

A safety valve whose thin-walled portion is broken by a predetermined pressure is covered in a hole formed in an outer container such as a battery, and the outer surface of the safety valve faces the periphery of the hole of the outer container. By contacting a reinforcing ring formed with a convex portion, the outer container, the safety valve, and the reinforcing ring are pressed and urged by a pair of welding electrodes and resistance-welded to thereby form a convex portion of the safety valve and the reinforcing ring. The electric current of resistance welding is concentrated on the line contact part of the product to generate high heat, and this high heat is also transmitted to the periphery of the hole of the outer container, and these are pressed and urged by the welding electrode. Resistance welding is performed instantaneously and reliably while being sandwiched between the outer container and the reinforcement ring while covering the hole of the, and the heat of welding is suitably transmitted to the outer container and the safety valve by stacking the reinforcement rings. And the welding point is mechanical Suitable bonding conditions are reinforced can be obtained.

When resistance welding is performed with a reinforcing ring interposed between the welding electrode and the safety valve, the heat of welding is suitably transmitted to the outer container and the safety valve, and the welding point is mechanically It is reinforced so that a suitable joined state can be obtained.

Alternatively, a lid is placed on the opening of an outer container such as a battery made of a cylindrical body, and a first welding electrode having a circular shape is provided on the outer peripheral edge of the lid, and the outer container. Even if the electrode body or the like is housed in the outer container by resistance welding the lid to the outer container by a second welding electrode that closely surrounds the outer container and surrounds the outer container. It becomes possible to resistance-weld the lid to the.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a first embodiment of an outer container such as a battery of the present invention is welded.

FIG. 2 is a cross-sectional view showing a first embodiment of an outer container such as a battery of the present invention.

FIG. 3 is a cross-sectional view showing a state in which a second embodiment of an outer container such as a battery of the present invention is welded.

FIG. 4 is a cross-sectional view showing a second embodiment of an outer container such as a battery of the present invention.

FIG. 5 is a cross-sectional view showing another embodiment of a ridge in an outer container such as a battery of the present invention.

FIG. 6 is a cross-sectional view showing another embodiment of the safety valve in the outer container such as the battery of the present invention.

FIG. 7 is a cross-sectional view showing still another embodiment of the safety valve in the outer container such as the battery of the present invention.

FIG. 8 is a cross-sectional view showing a state in which a third embodiment of an outer container such as a battery of the present invention is welded.

FIG. 9 is a cross-sectional view showing a state where a fourth embodiment of an outer container such as a battery of the present invention is welded.

FIG. 10 is a cross-sectional view showing a reinforcing ring in an outer container such as a battery of the present invention.

FIG. 11 is an exploded cross-sectional view of a fifth embodiment of an outer container such as a battery of the present invention.

FIG. 12 is a cross-sectional view showing a state in which a fifth embodiment of an outer container such as a battery of the present invention is welded.

[Explanation of symbols]

 1 Safety Valve 2 Exterior Container 2a Hole 3 Protruding Open Edge 4 Welding Electrode 5 Welding Electrode 6 Reinforcement Ring 6b Convex 7 Electrode Terminal 8 Lid 9 First Welding Electrode 10 Second Welding Electrode 12 Electrode Pin 13 Cap Body

Claims (6)

[Claims] 1. A safety valve in which an opening edge portion of a hole formed in an outer container such as a battery is projected to form a protruding opening edge portion, and a thin wall portion is broken at a predetermined pressure in the protruding opening edge portion. An outer container for a battery or the like, wherein the outer container and the safety valve are resistance-welded by being biased by a pair of welding electrodes. 2. A safety valve whose thin-walled portion is broken by a predetermined pressure is covered in a hole formed in an outer container such as a battery, and the outer surface of the safety valve faces the periphery of the hole of the outer container. An outer container for a battery or the like characterized in that the outer container, the safety valve and the reinforcing ring are abutted against a reinforcing ring formed with a convex portion and are resistance-welded by being biased by a pair of welding electrodes. . 3. The outer container for a battery or the like according to claim 1, wherein a resistance ring is interposed between the welding electrode and the welding portion of the safety valve by interposing a reinforcing ring. 4. A lid is placed on an opening of an outer container such as a battery having a cylindrical shape, and a first welding electrode having a circular shape is provided on an outer peripheral edge of the lid, and the outer container. An outer container such as a battery in which a lid is resistance-welded to the outer container by a second welding electrode that closely surrounds the outer container and surrounds the outer container. 5. An electrode pin having a brim on a columnar body inserted insulatively into a hole formed in an outer container of a battery or the like, and a hollow covering the tip of the columnar body through which the electrode pin is inserted. An outer container for a battery or the like, characterized in that the hole portion of the outer container is hermetically sealed by caulking the inverted frustoconical cap body. 6. The outer container for a battery or the like according to claim 5, wherein a lead tab is interposed between the electrode pin and the cap body to be caulked.