JPH09320562A - Sealed cylindrical nonaqueous secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed cylindrical nonaqueous secondary battery excellent in leakage resistance characteristic by completely shutting off current inside the battery at the initial stage of the buildup of the battery internal pressure if the battery has failed. SOLUTION: A group of electrodes 5 is enclosed, together with an electrolyte, inside a metallic, cylindrical battery outer case 1 serving also as a negative terminal, the battery outer case 1 is connected to the negative side of the group of electrodes 5, an insulative gasket 3 is placed on the inner periphery of an opening in the battery outer case 1, and the battery outer case 1 is closed by a disc-shaped plug 17 serving also as a positive terminal supported against the gasket 3; the plug 17 includes a metallic plug main body 4 electrically connected to the group of electrodes 5, a metallic terminal cap 2 insulated from the plug main body 4 and locked in place, a return switch 8 having a contact part 8a that establishes electrical conduction from the plug main body 4 to the terminal cap 2, and a non-return explosion-proof valve 10 that is displaced outward as the pressure within the battery outer case 1 builds up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed cylindrical non-aqueous secondary battery capable of interrupting a current path inside the battery when the internal pressure of the battery rises.

[0002]

2. Description of the Related Art In recent years, due to the high performance, miniaturization, and portability of electronic equipment, the battery used as the power source is
Higher energy densities are required. For rechargeable batteries that can be used for a long time by charge / discharge cycles, conventional sealed lead-acid batteries or nickel-cadmium batteries have recently been replaced with nickel-hydrogen batteries that use a hydrogen storage alloy for the negative electrode, or light metal insertion and release between the positive and negative electrodes. With the development of sealed non-aqueous secondary batteries, the market is rapidly expanding as a power source for new electronic devices. Particularly, as a representative of the latter, there is a lithium ion secondary battery using lithium as a light metal. This battery has a high battery voltage of 3.6 V, high energy density, low self-discharge, and excellent cycle characteristics. It is predicted that it will be widely used as a power source for portable electronic devices in the future.

Generally, in a sealed cylindrical non-aqueous secondary battery, an electrode group in which a positive electrode and a negative electrode are separated by a separator is used.
A positive electrode supported by the gasket is housed together with an electrolytic solution in a metal cylindrical battery outer can that also serves as a negative electrode or a positive electrode terminal, and an insulating gasket is arranged on the inner periphery of the opening of the battery outer can. The battery outer can is closed by the disk-shaped sealing body that also serves as the negative electrode terminal. To ensure the safety of this battery, measures to prevent leakage of the electrolyte solution contained in the battery and when the battery is abnormal It is extremely important to take measures against the rise in the internal pressure of the battery due to the heat generation. Possible locations of liquid leakage are firstly an exhaust hole communicating from the inside of the sealing body to the outside, secondly the interface between the sealing body and the gasket, and thirdly the interface between the battery case and the gasket. In addition, as a situation in which the battery internal pressure rises, an external short circuit, an internal short circuit, or overcharge may be considered. In these cases, the temperature of the battery itself rises and the internal pressure of the battery rises due to the vaporization of the electrolytic solution contained therein. Therefore, if this state continues, the battery may explode, possibly damaging peripheral equipment.

Therefore, in this type of battery, as a measure against liquid leakage, a sealant for preventing liquid leakage of the electrolytic solution may be applied to the interface between the battery outer can and the gasket and the interface between the sealing body and the gasket. It is being appreciated. Further, as a measure against battery abnormality, an explosion-proof valve capable of releasing gas inside the battery to the outside when a predetermined battery internal pressure is reached is provided in the sealing body. The structure of this sealing body is described in Japanese Patent Application Laid-Open No. 2-112.
No. 151 and Japanese Utility Model Application Laid-Open No. 5-62956 disclose that the explosion-proof valve is broken due to an increase in battery internal pressure to simultaneously release the battery internal pressure and interrupt the current path, and JP-A-7-320711. As described in the publication, the release of the battery internal pressure and the interruption of the current path are performed by different mechanisms.The explosion-proof valve is deformed by the increase in the battery internal pressure and the non-reset type switch is activated to interrupt the current path. Further, there is one in which the current path is not restored even if the explosion-proof valve is broken to release the battery internal pressure.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The ones described in Japanese Patent Publication No. 1 and Japanese Utility Model Publication No. 5-62956 are
As shown in FIGS. 3 and 4, the battery internal pressure is released by breaking the breakage portion 10b of the explosion-proof valve 10, and the current is cut off at the same time as the breakage. The explosion-proof valve 10 itself cuts off the current path. Explosion-proof valve 1 because it is a switch
Due to the attachment of the electrolyte solution at the time of zero breakage and the contact of the breakage portion 10b in a floating state, the interruption of the current path is not completely achieved, and especially during overcharge, the battery reaction continues and the battery temperature rises sharply. There is a risk of fire. Further, in the one described in Japanese Patent Application Laid-Open No. 2-112151 shown in FIG. 3, since the electrode group 5 side of the explosion-proof valve 10 is exposed to the electrolytic solution atmosphere even in the normal use state of the battery, the electrolytic solution is regarded as the explosion-proof valve 10. There is a risk of permeation and leakage from the interface with the sealing body 4.

Further, in the one disclosed in Japanese Patent Laid-Open No. 7-320711, as shown in FIGS. 5 and 6, the explosion-proof valve 10 is deformed to bulge outward in the battery due to an increase in the internal pressure of the battery (FIG. 6 shows after the deformation respectively),
Operation pin 7 of the non-reset type switch 18 facing the outside of the battery
By pressing, the spring of the non-returning type switch 18 is reversely locked, the contact portion 18a of the non-returning type switch is cut off to interrupt the current path, and further, the breaking portion 10b of the explosion-proof valve 10 is broken to release the battery internal pressure. However, since the non-returning type switch 18 is locked and the contact portion 18a is maintained in the disconnected state, the following problems may occur. That is, first, since the non-reset type switch 18 is made of a relatively hard spring material such as a nickel-plated steel plate and is used to reverse lock, the operating pressure (spring constant) of the switch is It will be relatively high. Secondly, it is difficult to design the operating pressure of the non-reset type switch 18 on the secondary side with priority over the deforming force of the explosion-proof valve 10 that receives the direct pressure of the battery internal pressure. Thirdly, as the internal pressure of the battery rises, the contact portion 18 of the non-reset type switch
Since the contact pressure of a decreases, the energization of the current path becomes unstable.

Further, even when the battery is normally used, there is a risk of liquid leakage from the interface between the explosion-proof valve 10 and the sealing body 4, and the sealing body 4 to the terminal cap 2 have 5 to 6 layers. Since it has a laminated structure of layers, there is a risk of permeation leakage at the interface between the laminated part and the gasket 3 or between the layers of the laminated part.

[0008]

In order to solve the above-mentioned problems, the present invention relates to a metal cylindrical battery outer can in which an electrode group in which a positive electrode and a negative electrode are separated by interposing a separator also serves as a negative electrode or a positive electrode terminal. The battery outer can is housed together with an electrolytic solution in the inside of the battery outer can, and an insulating gasket is arranged on the inner periphery of the opening of the battery outer can, and the disk-shaped sealing body supported by the gasket also serves as a positive or negative electrode terminal. A sealed cylindrical non-aqueous secondary battery, in which the sealing body is a metal sealing body electrically connected to the electrode group, and is insulated and fixed from the sealing body. A metallic terminal cap, a resettable switch having a contact portion for electrical conduction from the sealing body to the terminal cap, and a non-restoration type explosion-proof which is displaced outward in accordance with a pressure increase in the battery outer can. Equipped with valve , The contact portion, the away pushed outward displacement of the direction of the explosion-proof valve, the is to cut off the electrical conduction to the terminal cap, it is characterized.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A sealing body comprises a metal sealing body body electrically connected to the electrode group, a metal terminal cap insulated and fixed from the sealing body body, and the sealing body body. From the terminal cap to a resettable switch having a contact point for electrical conduction, and a non-resettable explosion-proof valve that is displaced outward in response to a rise in pressure inside the battery outer can, the contact point section comprising: When the internal pressure of the battery rises when the battery malfunctions, the non-reset type explosion-proof valve is pressed by the outward displacement of the explosion-proof valve to separate from the terminal cap and cut off the electrical continuity to the terminal cap. Is displaced outward,
It is possible to secure safety by pushing up the resettable switch to cut off the electrical continuity of the contact portion and stopping the battery reaction at the initial stage of the rise in the battery internal pressure. At this time, since the explosion-proof valve is a non-reset type, if the operating pressure of the explosion-proof valve is determined, the operating pressure of the reset-type switch, that is, the operating pressure when the current is cut off can be uniquely determined.

The sealing body has an opening communicating from the inside of the battery case to the sealing body, and the terminal cap has an exhaust hole communicating from the sealing body to outside air. The explosion-proof valve is arranged so as to seal the opening of the sealing body, and has a non-returning spring disc that reversely locks when it is displaced outward due to a pressure increase in the battery outer can, and an excessive The breakable portion that breaks due to a pressure increase, the resettable switch has a spring constant smaller than the spring constant of the non-returnable spring disk of the explosion-proof valve, and is directed outward of the explosion-proof valve. By following the displacement of
The explosion-proof valve has two functions, that is, the operation of the resettable switch by reversing lock of the non-returnable spring disk, that is, current interruption, and the battery internal pressure release due to the breakage of the breaking portion. The working pressure can be designed by giving priority to the structure of the explosion-proof valve. The non-returning spring disk has a thickness adjusted by a metal material such as a nickel plate, a nickel-plated steel plate or a nickel-containing alloy such as stainless steel so that the non-returning operation is performed during the deformation operation. It is preferable to set it so that the pressure rise occurs in the range of 0.2 to 1.2 MPa, preferably 0.4 to 0.6 MPa. Since the non-returning type spring disk operates the return type switch for the first time by the reversal lock to cut off the current, the energization of the current path does not become unstable before the reversal lock.

In order to operate the resettable switch with an operating force (spring constant) smaller than the operating pressure of the non-resettable spring disk, the material of the resettable switch is aluminum, copper, or an alloy thereof. Alternatively, those obtained by plating these metal materials with silver or the like are preferable.

Between the sealing body and the reset type switch or between the reset type switch and the terminal cap,
Positive temperature characteristic Thermistor electrically intervenes to interrupt the current in the event of abnormal temperature rise of the battery or high current conduction, and combined with the current interrupt action by the reset type switch when the battery internal pressure rises. Battery safety.

Between the periphery of the explosion-proof valve and the sealing body,
By providing a gasket, it is possible to prevent the electrolyte from penetrating and leaking inside the sealing body, effectively protecting the resettable switch from corrosion due to electrolyte leaking liquid, and also preventing the permeation of water etc. from the outside of the battery. be able to. The gasket is preferably a ring-shaped integrally molded rubber such as an O-ring, and materials such as olefin rubber, fluorine rubber, and butyl rubber can be used.

The ruptured portion is formed of a thin film having poor air permeability, and is formed of a metal foil or a resin film or a combination of metal and resin. In the case of a metal foil, the metal foil is an electrolytic solution or another kind of metal. In order to prevent the occurrence of corrosion due to contact with the parts, and to ensure that the operating pressure of the explosion-proof valve and the breaking pressure of the breaking part always operate at appropriate values, coating or laminating a thin film layer of resin on the metal foil It is desirable that they be superposed. The metal foil is preferably aluminum foil or copper foil,
The rupture of the rupture portion preferably increases the internal pressure of the battery by 1.3.
Set to occur in the range of ~ 2.5 MPa. If the internal pressure of the battery continues to rise even after the resettable switch is pushed up by the outward displacement of the non-resettable explosion-proof valve to disconnect the electrical connection of the contact part, the breakage of the breakage occurs.

The breaking portion is fixed so that the thin film closes an opening provided in the vicinity of the center of the non-returning type spring disc, and is projected in the outward displacement direction of the explosion-proof valve. During a sudden pressure increase,
It is possible to prevent the breakage of the thin film from occurring instantly.

[0016]

The present invention will be described below in detail with reference to examples. FIG. 1 is an element cross-sectional view of a sealed cylindrical non-aqueous secondary battery manufactured according to the present invention. The electrode group 5 in which the positive electrode and the negative electrode are separated by the interposition of the separator is housed together with the electrolytic solution in the metal cylindrical battery outer can 1 that also serves as the negative electrode terminal, and the battery outer can 1 is connected to the negative electrode side of the electrode group 5. The battery outer can 1 is closed by a disk-shaped sealing body 17 which is connected to the inner periphery of the opening of the battery outer can 1 and has an insulating property, and which is supported by the gasket 3 and also serves as a positive electrode terminal. The sealing body 17 includes a metallic sealing body body 4 electrically connected to the electrode group 5, and the sealing body body 4
A metal terminal cap 2 which is insulated and fixed from
A resettable switch 8 having a contact portion 8a for electrical conduction from the sealing body 4 to the terminal cap 2 and a non-restoration type explosion-proof valve 10 which is displaced outward in accordance with a pressure increase in the battery case 1 are provided. The contact portion 8a is pushed by the displacement of the explosion-proof valve 10 in the outward direction, and is separated from the contact portion 8a to cut off the electrical conduction to the terminal cap 2.

The sealing body 4 has an opening 18 communicating from the inside of the battery outer can 1 to the inside of the sealing body 17, and the terminal cap 2
Has an exhaust hole 11 that communicates from the inside of the sealing body 17 to the outside air, and the explosion-proof valve 10 is arranged so as to seal the opening 18 of the sealing body main body 4, so that the pressure inside the battery outer can 1 rises. Has a non-returning spring disk 10a that reversely locks when it is displaced outward, and a breaking portion 10b that breaks due to excessive pressure rise. The returning switch 8 is a non-returning spring of the explosion-proof valve 10. Disk 10a
Explosion-proof valve 10 has a spring constant smaller than that of
Of the contact point portion 8a and the circumferential portion 8b. The contact portion 8a is formed at the center of the contact portion 8a in response to the outward displacement of the non-returning spring disk 10a. It has an operating pin 7 to be displaced.

The battery outer can 1 used was a bottomed cylinder having an outer diameter of 18 mm, and the electrolytic solution used was propylene carbonate and diethyl carbonate in a ratio of 1: 1 v.
About 1 mol% of lithium hexafluorophosphate was added as a solute to a mixture of ol%. Further, the sealant 16 is applied to the interface between the battery outer can 1 and the gasket 3 and the interface between the gasket 3 and the sealing body 4, and the gasket 3 is made of a fluororesin (perfluoroalkoxy resin). ) Is used as the sealant 16.
It uses a mixture of pitch and natural rubber.

Explaining the structure of the sealing body 17 in detail, the aluminum integrally molded sealing body body 4 on the innermost side of the battery is as follows.
The tab terminal 6 taken out from the positive electrode of the electrode group 5 is welded and joined, the opening main body 4 has an opening 18 for degassing, and the opening 18 is depressed toward the inner side of the battery. It has a concave portion, and in the concave portion, a disk-shaped explosion-proof valve 10 having a central portion protruding inward of the battery is provided. Explosion-proof valve 10
A non-returning spring disk 10a in which a central hole 19 provided in the central portion is bent so as to project inward of the battery.
And a rupture portion 10b in which an aluminum foil is attached from the inside of the battery so as to close the center hole 19, and the rupture portion 10b projects from the center hole 19 toward the outside of the battery. Further, the breaking portion 10b is laminated with a polypropylene film to prevent corrosion due to contact with an electrolytic solution or contact with a dissimilar metal. Between the explosion-proof valve 10 and the sealing body 4, an EP mainly intended to seal the electrolytic solution.
It has a ring-shaped gasket 3'made of DM, and the gasket 3'is compressed and held in the concave portion of the sealing body 4 in order to improve the adhesion. The explosion-proof valve 10 is held between the gasket 3'and the ring-shaped positive temperature characteristic thermistor 9, and the inside of the sealing body 17 is plated with silver of the same outer diameter on the ring-shaped positive temperature characteristic thermistor 9. A contact ring 12 made of copper, an insulating plate 13, a circumferential portion 8b of a resettable switch 8 made of silver-plated copper alloy, and a terminal cap 2 are laminated in this order, and the whole of the outer circumference thereof. Is insulated from the sealing body 4 by a cylindrical polypropylene insulating ring 14, and is crimped by bending the peripheral edge of the sealing body 4.

In FIG. 2, the spring disk 10a of the explosion-proof valve 10 reversely locks toward the outside of the battery as the internal pressure of the battery rises due to overcharging, and pushes up the operating pin 7 provided at the center of the resettable switch 8 to contact the contact portion. 8a shows the state in which the current path is cut off by separating. Spring disc 1
0a was set to reverse lock in the outward direction of the battery when the internal pressure of the battery reached 0.5 MPa. Further, the breakage portion 10b was set so as to be broken when the internal pressure of the battery reached 1.5 MPa.

The battery of the present invention having a sealing body having the above structure is referred to as Example 1, and a battery obtained by removing the gasket 3'inside the sealing body 17 from Example 1 is referred to as Example 2 and the conventional battery shown in FIG. Using the battery as the conventional example 1 and the conventional battery shown in FIG. 5 as the conventional example 2, the presence or absence of liquid leakage from three paths of 20 batteries was tested. Here, the path 1 is from the inside of the sealing body 17 to the exhaust hole 11, the path 2 is between the sealing body 17 and the gasket 3, the path 3 is between the gasket 3 and the battery outer can 1, and the test conditions are the following two conditions. Table 1 shows the percentage display of the number of leaked batteries. Test 1. Inverted at room temperature and humidity (closed side facing down) 100 days test 2. 30 days of standing upside down (sealing body side facing down) at 60 ° C. and 90% humidity 30 days From these results, better leakage resistance was obtained in Example 1 and Example 2 as compared with Conventional Example 1 and Conventional Example 2.

[0022]

[Table 1]

FIG. 7 shows the increase in the internal pressure of the battery of the present invention in the case of overcharging when continuously charged at a constant current at a current value of 20% of the battery rated capacity under normal temperature and normal humidity.
It is the figure which expressed the charge amount at that time as 100% at the time of full charge of a battery rated capacity. In consideration of the safety of the battery such as heat generation, it is preferable that the current path is cut off until the charging capacity of the battery rated capacity is about 350% (overcharge rate is about 250%). By selecting an explosion-proof valve that operates when the non-returning type spring disc reversely locks at a desired pressure value in the range indicated by the arrow A in the figure, that is, the battery internal pressure is in the range of 0.2 to 1.2 MPa, the desired value can be easily selected. The current can be cut off at the operating pressure of.

Next, in the first embodiment, the outer diameter of the positive temperature characteristic thermistor 9 is reduced, and an insulating ring-shaped spacer 20 (made of polytetrafluoroethylene) is interposed in the void formed thereby. (Example 3). FIG. 9 shows the situation. This configuration is such that between the circumferential portion 8b of the resettable switch 8 and the terminal cap 2,
It is equivalent to a structure in which a positive temperature characteristic thermistor is electrically interposed, and an insulating ring-shaped spacer (made of polytetrafluoroethylene) is interposed in a void formed by reducing the outer diameter of the positive temperature characteristic thermistor. . Further, a positive temperature characteristic thermistor 9 is electrically interposed between the sealing body 4 and the circumferential portion 8b of the resettable switch 8 (the positive temperature characteristic thermistor 9 is positioned in contact with the sealing body 4). In the void formed by reducing the outer diameter of the positive temperature characteristic thermistor 9,
The insulating means between the sealing body 4 and the terminal cap 2, that is, the edge of the insulating ring 14 is extended and interposed (Example 4). FIG. 10 shows the situation.

In Table 2, the batteries of Examples 1, 3 and 4 (5 each) were overcharged with a constant current at a current value three times the rated capacity, at which time the positive temperature characteristic thermistor was activated. Showed the time. In the batteries of Example 1, the positive temperature characteristic thermistor was operated and not operated. Since there is an explosion-proof valve as another safety measure, there was no concern about the battery exploding even if the positive temperature characteristic thermistor did not operate, but higher safety is desirable considering the malfunction of the resettable switch. On the other hand, in the batteries of Examples 3 and 4, the operation start time of the positive temperature characteristic thermistor was almost constant in each battery. This is because the positive temperature characteristic thermistor does not excessively pressurize and operates normally due to the presence of the extended portion of the spacer 20 or the edge of the insulating ring 14. The positive temperature characteristic thermistor ensures the normal operation, which further enhances safety.

[0026]

[Table 2]

The outward displacement of the non-reset type explosion-proof valve 10 is such that the internal pressure of the battery rises within the range of 0.2 to 1.2 MPa, preferably 0.4 to 0.6 MPa. Is good. In order to confirm this, in Example 1, the non-returning type spring disk 10a was variously changed, and the non-returning type spring disk 10a was deformed when the increase in the battery internal pressure reached each value shown in Table 3. It was set to reverse lock. Then, the battery was charged at the same current as the battery rated capacity (the positive temperature characteristic thermistor does not operate at this charging current). The presence or absence of battery rupture during overcharge is shown in Table 3 for each of the five batteries. In addition, in order to clarify the influence of the change of the non-returning type spring disk 10a, the breakage portion 10b has a rise in the battery internal pressure of 3.0M.
It was set to break when reaching Pa. As is clear from Table 3, the battery did not burst when the internal pressure of the battery increased by 0.6 MPa or less. This is because when the internal pressure of the battery rises below 0.6 MPa, the non-recoverable spring disk 10a deforms and the charging current is cut off, the battery temperature rises only slightly, but the non-recoverable spring disk 10a deforms. Even if the charging current is cut off due to operation, if the internal pressure of the battery rises above 1.2 MPa at that time, the temperature has already risen inside the battery and decomposition of the electrolyte has already occurred. It is presumed that the temperature of the battery further rises due to the heat of the battery and causes the battery to burst.

[0028]

[Table 3]

The breaking of the breaking portion 10b is performed by increasing the internal pressure of the battery by 1.3 to 2.5 MPa, preferably 1.3 to 1.5.
It is better to occur in the range of MPa. In order to confirm this, in Example 1, the fractured portion 10b
Was changed variously, and the breakage portion 10b was set to break when the increase in the internal pressure of the battery reached each value in Table 4. Then, the battery was charged at the same current as the battery rated capacity (the positive temperature characteristic thermistor does not operate at this charging current). The presence or absence of battery rupture during overcharge is shown in Table 4 for each of the five batteries. In the case where the breakage portion 10b was set to break when the increase in the internal pressure of the battery was 1.5 MPa or less, not only the battery burst but also the deformation of the battery outer can did not occur. Even if the breakage portion 10b is set to break when the increase in the battery internal pressure exceeds 1.5 MPa, the breakage portion 10b is set to break when the increase in the battery internal pressure is 2.5 MPa or less. Although the battery did not explode, the bottom of the battery outer can was deformed. In the case where the breakage portion 10b was set to break when the increase in the internal pressure of the battery was 3.0 MPa, there were some cases in which the battery burst. It is presumed that this is because the battery internal pressure became too high and the battery temperature increased abnormally. It should be noted that the lower limit value of the internal pressure rise of the battery at which the breakage of the breakage part 10b occurs 1.3M
Pa is a consideration to prevent breakage of the breakage portion 10b due to an increase in battery internal pressure that causes the non-returning spring disk 10a to deform.

[0030]

[Table 4]

[0031]

As described above, in the sealed cylindrical non-aqueous secondary battery according to the present invention, the non-return type explosion-proof valve which is displaced outward when the internal pressure of the battery rises when the battery is abnormal, follows this displacement. When the explosion-proof valve that operates at the desired pressure value is determined by pressing the return-type switch to the outward direction to release the contact and disconnecting the current path to the terminal cap, The current can be easily cut off, and the electric conduction can be surely cut off even in the initial stage when the battery internal pressure rises. Further, the operating pressure of the break switch of the current path can be designed to a low value of about 0.2 MPa, which was difficult in the past, and the liquid leakage resistance of the battery can be made excellent.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a sealed cylindrical non-aqueous secondary battery according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts showing a state in which a non-reset type explosion-proof valve and a reset type switch in FIG. 1 are operated.

FIG. 3 is a cross-sectional view of an essential part showing an example of a conventional sealed cylindrical secondary battery.

FIG. 4 is a cross-sectional view of essential parts showing an example of a conventional sealed cylindrical secondary battery.

FIG. 5 is a cross-sectional view of an essential part showing an example of a conventional sealed cylindrical secondary battery.

FIG. 6 is a cross-sectional view of essential parts showing a state in which the explosion-proof valve and the non-reset type switch in FIG.

FIG. 7 shows a rise in internal pressure of a battery in the case of overcharging of a sealed cylindrical non-aqueous secondary battery according to an embodiment of the present invention,
It is the figure which expressed the charge amount at that time as 100% at the time of full charge of a battery rated capacity.

FIG. 8 is an enlarged view of FIG. 1.

FIG. 9 is a cross-sectional view of essential parts of a sealed cylindrical non-aqueous secondary battery according to another embodiment of the present invention.

FIG. 10 is a cross-sectional view of essential parts of a sealed cylindrical non-aqueous secondary battery according to still another embodiment of the present invention.

[Explanation of symbols]

1 is a battery outer can, 2 is a terminal cap, 3 and 3'is a gasket, 4 is a sealing body, 5 is an electrode group, 6 is a tab terminal, 7 is an operating pin, 8 is a reset switch, 8a is a contact part, 8b Is a circumferential portion, 9 is a positive temperature characteristic thermistor, 10 is an explosion-proof valve, 10
a is a non-returnable spring disk, 10b is a fractured part, 1 is
1 is an exhaust hole, 12 is a contact ring, 13 is an insulating plate, 14 is an insulating ring, 15 is an insulator, 16 is a sealant, 1
7 is a sealing body, 18 is an opening, 19 is a central hole, 20 is a spacer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Shinji Saito, Shinko Saito Electric Co., Ltd. 2-8-7 Nihonbashihonmachi, Chuo-ku, Tokyo (72) Inventor Akira Imoto 380 Tamate, Gosho-shi, Nara Waco Electronic Co., Ltd. Inside the Gosho Office (72) Inventor Toshizo Kameishi 380 Tamate, Gosho City, Nara Prefecture Waco Electronics Co., Ltd. Inside the Gosho Office

Claims (12)

[Claims] 1. An electrode group in which a positive electrode and a negative electrode are separated by a separator interposed between them is housed together with an electrolytic solution in a metal cylindrical battery outer can that also serves as a negative electrode or a positive electrode terminal, and inside the opening of the battery outer can. A sealed cylindrical non-aqueous secondary battery in which a battery-like outer can is closed by a disk-shaped sealing body having an insulating gasket disposed around its periphery and also serving as a positive electrode or a negative electrode terminal supported by the gasket. The sealing body includes a metal sealing body body electrically connected to the electrode group, a metal terminal cap insulated and fixed from the sealing body body, and the sealing body body to the terminal cap. A resettable switch having an electrically conductive contact portion and a non-resettable explosion-proof valve that is displaced outward in accordance with a rise in pressure inside the battery outer can are provided, and the contact portion is of the explosion-proof valve. Change outward The pressed apart, it is to cut off the electrical conduction to the terminal cap, a closed cylindrical nonaqueous secondary battery, characterized in that. 2. The sealing body has an opening communicating from the inside of the battery outer can to the sealing body, and the terminal cap has an exhaust hole communicating from the sealing body to outside air. The explosion-proof valve is arranged so as to seal the opening of the sealing body, and a non-returning spring disc that reversely locks when displaced outward due to a pressure increase in the battery outer can, It has a breaking portion that breaks due to excessive pressure rise, the reset switch has a small spring constant as compared to the spring constant of the non-return spring disc of the explosion-proof valve,
To follow the outward displacement of the explosion-proof valve,
The sealed cylindrical type non-aqueous secondary battery according to claim 1. 3. Between the sealing body and the reset type switch, or between the reset type switch and the terminal cap,
The sealed cylindrical non-aqueous secondary battery according to claim 1, wherein a positive temperature characteristic thermistor is electrically interposed. 4. Between the periphery of the explosion-proof valve and the sealing body,
The sealed cylindrical non-aqueous secondary battery according to claim 1, further comprising a gasket. 5. The closed cylindrical non-shape according to claim 2, wherein the broken portion is formed of a thin film having poor air permeability, and is formed of a metal foil, a resin film, or a combination of metal and resin. Water secondary battery. 6. The breaking portion is fixed so that the thin film closes an opening provided in the vicinity of the center of the non-returning type spring disc, and projects in the outward displacement direction of the explosion-proof valve. The sealed cylindrical type non-aqueous secondary battery according to claim 5. 7. A positive temperature characteristic thermistor is reduced in outer diameter,
The sealed cylindrical non-aqueous secondary battery according to claim 3, wherein an insulating spacer is interposed in the void formed thereby. 8. A positive temperature characteristic thermistor is electrically interposed between the main body of the sealing body and the reset type switch, and the sealing body is placed in a space formed by reducing the outer diameter of the thermistor having the positive temperature characteristic. The sealed cylindrical non-aqueous secondary battery according to claim 1, wherein an insulating means is extended and interposed between the main body and the metal terminal cap. 9. The displacement of the non-reset type explosion-proof valve in the outward direction is
The sealed cylindrical non-aqueous secondary battery according to claim 1, wherein the internal pressure of the battery is raised within a range of 0.2 to 1.2 MPa. 10. The sealed cylindrical non-aqueous secondary battery according to claim 9, wherein the outward displacement of the non-reset type explosion-proof valve occurs when the internal pressure of the battery increases by 0.6 MPa or less. 11. The closed cylindrical non-aqueous liquid according to claim 2, wherein the breakage of the breakage portion occurs within the range of an increase in the internal pressure of the battery of 1.3 to 2.5 MPa. Secondary battery. 12. The sealed cylindrical non-aqueous secondary battery according to claim 11, wherein the breakage of the breakage portion occurs when the internal pressure of the battery increases by 1.5 MPa or less.