WO2001078165A1

WO2001078165A1 - Enclosed battery, sealed body, and outer packaged container

Info

Publication number: WO2001078165A1
Application number: PCT/JP2001/002436
Authority: WO
Inventors: Hiroaki Kawamura; Akira Kaneko; Yoshihiko Isobe; Kunio Nishimura
Original assignee: Toyo Kohan Co., Ltd.
Priority date: 2000-04-05
Filing date: 2001-03-27
Publication date: 2001-10-18
Also published as: JP2001291502A; AU4456101A

Abstract

A totally enclosed battery capable of effectively preventing the temperature rise and explosion of the battery when the internal pressure of the battery rises due to short-circuit, overcharging, or reverse charging and allowing a battery internal pressure to be released immediately upon the shutdown of a current in order to assure the safety and reliability of the battery, comprising a sealed body or an outer packaged container having a structure formed of a first flat contact surface comprising a metal substrate having circular through holes provided on an endless periphery or linear through holes apart a small distance from each other and metallic foils stuck on the inner surface of the metal substrate so as to close the circular through holes or linear through holes, having a portion of the metal substrate with a small interval deformable with a small force extended when a battery internal pressure rises, and allowing a portion surrounded by the circular through holes or linear through holes provided on an endless periphery to be projected.

Description

Description Sealed battery, sealing body and outer can Technical field

The present invention relates to a sealed battery, a sealing body, and an outer can that can be ruptured at a predetermined pressure, particularly at low pressure, when the battery temperature or battery internal pressure increases, to release the internal pressure promptly and at the same time to cut off the current. . Background art

In recent years, the use of non-aqueous electrolytes, such as lithium ion secondary batteries, which are lightweight and have a high energy density, has become commonplace in response to the demand for smaller and higher performance electronic devices. . Also, lithium polymer batteries using gel electrolytes, which are non-aqueous electrolytes, have been put into practical use. In these non-aqueous batteries, which use an alkali metal such as lithium as the active material of the negative electrode, the alkali metal reacts very easily with water and generates gas. . Such a completely sealed battery has the advantage of excellent storage properties, but on the other hand, because of its high sealing properties, it is exposed to high temperatures, short-circuited inside or outside the battery, and a large current flows. Hydrogen gas generated by water mixed in during production can cause abnormal rise in internal pressure of the battery, causing the battery to rupture and damage equipment, and in some cases, injure the user. Therefore, a mechanism is required to release the pressure to the outside before the internal pressure becomes too high.

Several methods have been proposed to release internal pressure to the outside, and some of them have been put to practical use. For example, in Japanese Patent Application Laid-Open No. 2-304861, a valve chamber having a valve hole communicating with the inside of the battery and an exhaust hole communicating with the outside is formed in a part of the outer can, and at least the valve hole is formed in the valve chamber. A valve body made of rubber whose surface facing the side and the rubber surface of the valve body This is a safety valve equipped with an elastic body that presses the valve into the valve hole.The rubber seals the valve hole to maintain hermeticity, and when the internal pressure rises, the valve opens when the internal pressure reaches the release pressure set in advance for the elastic body. The hole is opened to prevent the internal pressure from rising more than the set value. Conventional safety valves with this structure are already widely used in N1-Cd batteries, but are required for non-aqueous batteries even when the elastic body presses the valve body into the valve hole and seals it. Since such high sealing properties cannot be obtained, it cannot be adopted for nonaqueous batteries using an alkali metal as the negative electrode active material.

As a mechanism for releasing the internal pressure of the battery required to have high sealing performance to the outside, there is a thin wall portion on a part of the outer can wall as disclosed in Japanese Patent Application Laid-Open No. Sho 63-2858559. The method of forming the thin inner part is to cold compress the can wall with a suitable press device and to provide a part of the can wall with a thickness of about half of the original thickness. Since the processing is only to change the shape, the sealability at this place is good.

Further, as this kind of relief mechanism, there is one disclosed in Japanese Patent Application Laid-Open No. Hei 6-215760. In this relief mechanism, a valve membrane is provided in an opening above an electrode body in a bottomed cylindrical outer can, and a current interrupting lead is provided above the valve membrane. When the pressure inside the battery rises, the valve membrane swells and breaks the current interrupt lead, interrupting the current.

However, according to the method disclosed in Japanese Patent Application Laid-Open No. 63-285585, it is necessary to reduce the thickness of the thin portion in order to operate at a relatively low pressure. This causes micro-cracks in the thin part, resulting in loss of hermeticity. In addition, cold working of metal always causes work hardening, but the method of hardening is not constant, so there is the disadvantage that operating pressure varies. Another disadvantage is that the safety valve is easily damaged during manufacture or use of the battery, and may be damaged in some cases. Half-etching is also available as a method of forming a thin-walled part, but this method makes it difficult to control the remaining etching thickness due to manufacturing, resulting in poor yield. Another problem is that a pinhole is generated in the half-etched part, and 100% inspection is performed. It was also necessary. Further, in the method disclosed in Japanese Patent Application Laid-Open No. 6-215570, in order to cut off the current interrupting lead at a predetermined pressure, the depth of a cut portion formed in the lead must be made accurate. There was a problem in processing, and there was a problem that current was not shut off stably at a predetermined pressure.

In order to solve the above-mentioned drawbacks of the prior art, the present invention provides a valve element which can be stably and accurately obtained at a low pressure, can be released at a predetermined pressure to release the internal pressure promptly, and is easily manufactured. A technical problem is to provide a sealed battery having a chip, a sealing body and an outer can used for the battery. Further, the present invention provides a sealing body, an outer can, and a sealing body having a structure that is easy to handle and hard to generate a defective portion that cannot be adopted as a product when manufacturing the above-described sealing body and the outer can. Providing sealed batteries is also a technical issue. Disclosure of the invention

In order to solve these problems, according to the present invention, an electrode body composed of a positive electrode, a negative electrode, and a separator is housed in a battery outer can together with an electrolytic solution, and is fitted and supported on the inner periphery of the outer can opening. In the hermetically sealed battery in which the outer can opening is closed by the sealing body, the sealing body is formed from a metal substrate having a circular or linear through hole provided on an endless circumference with a small space therebetween. And a metal foil laminated on the inner surface of the metal substrate so as to close the through-hole, wherein the metal plate can be easily deformed with a small force when the internal pressure of the battery rises. The present invention provides a sealed battery in which a narrow portion and an interval portion extend to protrude a valve body portion surrounded by a circular or linear through hole provided on the endless periphery. Further, the present invention provides a sealed battery including an outer can having such a valve structure.

According to the configuration of the present invention, the valve body chip made of a metal base having a circular or linear through-hole and a metal foil laminated with a metal plate so as to close the through-hole is used as a pressure-receiving plate. When the internal pressure of the battery rises, The flat contact surface portion of 1 protrudes, and the welded portion breaks further, electrically separating from the metal foil and interrupting the electrical connection. Further, when the internal pressure of the battery rises, the metal foil laminated so as to close the opening of the valve body made of the metal plate having the through hole is broken and gas inside the battery is released to the outside, thereby preventing the explosion of the battery can. . Materials with this configuration can also be applied to battery outer cans. When the internal pressure of the battery rises, the laminated metal foil that closes the through hole breaks and gas is released to the outside.

The through holes are circular or linear, and each hole is on the endless circumference. The through hole may be a combination of a circular shape and a linear shape, or may be a linear shape only. The circle includes a circle, an ellipse, a march, and the like, and the size thereof is not particularly limited. In the case of a linear shape, the width of the through hole is not particularly limited, but is preferably in the range of 0.6 to 1.4 mm. In particular, in the case of a linear shape, since the width of the opening is narrow, when laminating metal foil, wrinkling of the foil at the opening is less likely to occur. Since the occurrence of wrinkles is small, a sealing body or an outer can having a stable operating pressure is obtained.

Further, the metal plate substrate is a steel plate, a stainless steel plate, a copper plate, an aluminum plate, a nickel plate, a lead plate, a chromium plate or an alloy plate thereof, and a metal plate obtained by plating these metal plates is preferable. The metal foil is preferably a steel foil, a stainless steel foil, a copper foil, an aluminum foil, a nickel foil, or a nickel alloy foil such as a nickel-iron alloy.

Thus, in the sealing body or the outer can of the present invention, a part of the sealing body or the outer can is deformed at a constant pressure due to the internal pressure of the battery, and a part of the sealing body or the outer can is broken at a constant pressure. It has a mechanism to release the internal pressure, and the internal pressure release pressure can be set arbitrarily by the material and thickness of the metal foil. These sealing bodies or outer cans can be used not only for secondary batteries such as lithium-ion batteries, polymer batteries, Ni-Cd batteries or nickel-hydrogen batteries, but also for primary batteries such as manganese batteries, alkaline manganese batteries or lithium batteries. Also applicable to batteries. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an upper longitudinal sectional view of an example of the completely sealed battery of the present invention. FIG. 2 is a plan view of an example of the sealing body having the valve body of the present invention. FIG. 3 is a longitudinal sectional view of the sealing body. FIG. 4 is an explanatory diagram of the operation of the sealing body when the battery internal pressure rises abnormally. FIG. 5 is a plan view of another example of the sealing body having the valve body of the present invention. FIG. 6 is a longitudinal sectional view of the sealing body. FIG. 7 is an explanatory diagram of the operation of the sealing body when the battery internal pressure rises abnormally.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments and examples of the present invention will be described with reference to the drawings. FIG. 1 is an upper longitudinal section of an example of the completely sealed battery of the present invention. FIG. 2 is a plan view of an example of a sealing body having a valve body. FIG. 3 is a longitudinal sectional view of the sealing body shown in FIG. 2, and FIG. 4 is an operation explanatory diagram of the sealing body when the battery internal pressure in the sealing body shown in FIG. FIG. 5 is a plan view of another example of a sealing body having a valve body. FIG. 6 is a longitudinal sectional view of the sealing body shown in FIG. 5, and FIG. 7 is an explanatory diagram of the operation of the sealing body when the internal pressure of the battery in the sealing body shown in FIG.

In FIG. 1, an electrode body 12 shielded from the outside in an electrolyte is accommodated in a bottomed cylindrical outer can 11 also serving as a negative electrode terminal. The electrode body 12 has a configuration in which a laminate of a positive electrode 13 and a negative electrode 15 provided in a state of being insulated and opposed to the positive electrode 13 via a separator 14 is spirally wound.

Sealing lid ² 1 having a gas vent hole ^{3 7} serving as a explosion-proof function and a positive electrode terminal are caulked via an insulating gasket 1 6 a to an upper end opening of the outer can 1 1. A pressure receiving plate 18 having a gas vent hole 24 is provided above the electrode body 12.

Between the pressure receiving plate 18 and the PTC thermistor element 23, which controls the current to an appropriate level by increasing the resistance value when the temperature rises, forms a sealing body for sealing the electrode body 12 and the like. A shielding plate 20 is provided, and the shielding plate 20 is a PTC thermistor element 2 3, the PTC thermistor element 23 is in contact with the sealing lid 21, and the PTC thermistor element 23 is caulked and fixed to the outer can 11 via the insulating gasket 16a.

Further, the inner surface of the shielding plate 20 forming a sealing body for closing the opening at the upper part of the battery is formed by applying a lead 17 to the inner surface of the pressure receiving plate 18 attached to the pressure receiving plate 18 by welding or the like. The lead wire 17 extends to the positive electrode 13 of the electrode body 12. Thus, a current path in the battery is formed.

The shielding plate 20 is substantially circular in plan view as shown in FIGS. 2 and 5, and the shielding plate 20 is a circular metal substrate 38 and a metal foil laminated and adhered to the inner surface of the metal substrate 38. The material of the metal substrate 38 is a steel plate, a stainless steel plate, a copper plate, an aluminum plate or an alloy plate of these metals, and the metal foil 34 is a steel foil or a stainless steel foil. Either a copper foil, an aluminum foil, a nickel foil or a nickel alloy foil such as a nickel-iron alloy is used.

In FIG. 2 showing an example of the present invention, in the metal substrate 38, a plurality of through holes 33 (crescent shape in FIG. 2) (n, three in FIG. 2) It is located on the dressing circumference 3 and is provided so as to be connected endlessly. These processes are performed, for example, by the following method. First, a crescent-shaped hole is punched in the metal substrate by pressing along the opening, and the space between the crescent-shaped holes is crushed so that the foil is not pressed during the subsequent cladding process and then cut. And cut out the opening. The base material of the cut-out opening is pushed into the original base material by the pushback method at the time of press working, and is used as a base material for cladding. As shown in FIG. 3, a metal foil 34 is laminated on a metal substrate 38 having a circular through hole 33 and a linear through hole 31 to produce a sealing body made of a clad material. A known method can be applied to the method for producing the clad material, and is not particularly limited. For example, as disclosed in Japanese Patent Application Laid-Open No. 1224184, a method of performing cold rolling at a low rolling reduction is particularly preferable because deformation due to rolling is small.

When the internal pressure of the battery rises, the sealing body shown in Fig. 3 has a circular through hole as shown in Fig. 4. The metal foil of 33 or the linear through hole 31 is broken, and gas is discharged to the outside through the gas vent hole 37 of the sealing lid 21 through the broken part of the metal foil.

Next, the operation in the event of an abnormality where the battery internal pressure increases will be described. When the internal pressure of the battery rises, as shown in FIGS. 2 and 5, the circular through-hole 33 or the linear through-hole 31 provided on the metal substrate 38 on the endless circumference is easily deformed. The portion extends evenly and the first flat contact surface 27 is pushed up. When the first flat contact surface 27 is pushed up, the pressure receiving plate 18 attached to the metal foil 34 is separated from the bonding portion, so that the current is reliably cut off. When the internal pressure of the battery further increases, as shown in FIGS. 4 and 7, the portion of the metal foil 34 closing the circular through-hole 33 or the linear through-hole 31 ruptures, and the valve opening is opened, thereby reducing the internal pressure of the battery. release. The released gas passes through the circular through hole 33 or the linear through hole 31 and is released to the outside from the gas vent hole 37 of the sealing lid 21.

In addition, as shown in Fig. 2, the shape of the through-hole in the shielding plate is not only that a plurality of crescent-shaped through-holes are provided so as to be continuous on the circumference, but also, for example, as shown in Fig. 5, The through-hole 31 may be configured such that it exists on the circumference of a circle centered on the center of the shielding plate 20.

According to the configuration of the present invention, when the internal pressure of the battery rises abnormally due to short-circuiting, overcharging, reverse charging, etc. in the completely sealed battery, the easily deformable portion sandwiched between the through-hole groups provided in the metal substrate 38 However, it extends stably and accurately at low pressure, protrudes the first flat contact surface 27, cuts the adhesive portion, and cuts off the electrical connection. When the internal pressure of the battery further increases, the portion that closed the circular through hole 33 or the linear through hole 31 of the metal foil 34 ruptures at a predetermined pressure to generate a valve hole, thereby discharging the gas inside the battery to the outside. As a result, it is possible to prevent sudden temperature rise and explosion of the battery. The pressure for operating the first flat contact surface 27 to protrude is such that the size of the easily deformable portion of the circular through hole 33 or the linear through hole 31 formed in the metal substrate 38 is within an appropriate range. By adjusting the material composition and selecting the material composition of the metal substrate 38. It can be set in the specified range. In addition, since the metal foil 34 closing the circular through-hole 33 or the linear through-hole 31 can be manufactured with high accuracy on the order of microns, a stable material can be obtained by selecting the material composition of the metal foil 34. Can be ruptured at operating pressure. Industrial applicability

As described above, according to the sealing body or the outer can of the present invention, even if the internal pressure of the battery increases due to short-circuiting, overcharging, reverse charging, or the like, when the internal pressure of the battery reaches a relatively low predetermined value. When the easily deformable portion provided on the metal substrate is deformed by a stable operating force and the internal pressure of the battery is further increased, the metal foil closing the through hole provided on the metal substrate is ruptured stably and accurately. The gas inside is exhausted to the outside, and it is possible to prevent sudden temperature rise and explosion of the battery. Also, since the opening of the sealing body or the outer can is covered with a metal plate, the metal foil is extremely unlikely to be damaged and damaged by an external impact or the like, and the safety is remarkably improved.

Claims

The scope of the claims

1. An electrode body composed of a positive electrode, a negative electrode, and a separator is housed in a battery outer can together with an electrolytic solution, and a sealing body fitted and supported in the inner periphery of the outer can opening. In a sealed battery in which an opening is closed, the sealing body has a circular and linear through-hole provided on an endless circumference with a small gap, and a metal cut along the entire circumference along the through-hole. A valve body made of a substrate, and a metal foil laminated on the inner surface of the metal substrate so as to close the through-hole, and when the internal pressure of the battery rises, closes the through-hole provided on the endless circumference. The sealed battery is characterized in that the damaged metal foil is deformed by a small force and breaks when the internal pressure further increases.

2. An electrode body composed of a positive electrode, a negative electrode, and a separator is housed in a battery outer can together with an electrolytic solution, and a sealing body fitted and supported on the inner periphery of the outer can opening. Wherein the sealing body has a linear through-hole provided on an endless circumference at a small interval, and a valve formed of a metal substrate cut along the entire circumference along the through-hole. And a metal foil that is laminated on the inner surface of the metal substrate so as to close the through-hole, and closes the through-hole provided on the endless periphery when the internal pressure of the battery increases. A sealed battery characterized in that the foil is small, deformed by force, and broken when the internal pressure rises.

3. An electrode body composed of a positive electrode, a negative electrode, and a separator is housed in a battery outer can together with an electrolytic solution, and a sealing body fitted and supported on the inner periphery of the outer can opening. Wherein the outer can has a circular and linear through-hole provided on an endless circumference with a small space therebetween, and is made of a metal cut all around the through-hole. An outer can and a metal foil that is laminated on the inner surface of the metal so as to close the through hole, and the metal that closes the through hole provided on the endless circumference when the internal pressure of the battery increases. A sealed battery characterized in that the foil is deformed by a small force and breaks when the internal pressure increases.

4. An electrode body composed of a positive electrode, a negative electrode, and a separator is housed in a battery outer can together with an electrolyte, and a sealing body fitted and supported on the inner periphery of the outer can opening. Wherein the outer can has a linear through-hole provided on an endless periphery at a small interval, and is made of a metal which is cut along the entire circumference along the through-hole. And a metal foil laminated on the inner surface of the metal substrate so as to close the through hole, and the metal foil closing the through hole provided on the endless periphery when the internal pressure of the battery increases. A sealed battery that is deformed by a small force and breaks when the internal pressure rises.

5. The metal foil that closes the through hole is attached to a pressure receiving plate for guiding current from the electrode body, and when the portion surrounded by the through hole protrudes due to battery internal pressure, the pressure receiving plate is closed. 3. The sealed battery according to claim 1, wherein the sealed battery is electrically separated from the metal foil to cut off electrical connection.

6. The sealed battery according to claim 1, 3, or 5, wherein the circular through-hole is a crescent-shaped hole or a circular hole.

7. The metal plate according to any one of claims 1 to 6, wherein the metal plate substrate is a steel plate, a stainless steel plate, a copper plate, an aluminum plate, a nickel plate, a lead plate, a chrome plate, or an alloy plate thereof. Sealed battery.

8. The metal plate substrate according to any one of claims 1 to 7, wherein a steel plate, a stainless steel plate, a copper plate, an aluminum plate, a nickel plate, a lead plate, a chromium plate, or an alloy plate thereof is plated. A sealed battery as described in Crab.

9. The sealed battery according to any one of claims 1 to 8, wherein the metal foil is a steel foil, a stainless steel foil, a copper foil, an aluminum foil, a nickel foil or a nickel-iron alloy foil.

10. A sealing body used for the battery according to any one of claims 1 to 2 or claims 5 to 9.

11. An outer can used for the battery according to any one of claims 3 to 9.