JPH09274900A - Sealed nonaqueous secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous secondary battery provided with a structure which does not cause electrolyte leakage and increase of battery resistance even if impact is applied. SOLUTION: This battery is produced by housing an electrode unit 2 manufactured by coiling a positive and a negative electrode 2a, 2b and a separator 2c, an upper part insulating plate 30, and a nonaqueous electrolytic liquid in a bottomed battery outer casing can 1 and closing the aperture part of the bottomed battery outer easing can 1 with a sealing body fitted in and supported by an insulating gasket 5. In this case, the sealing body comprises a positive electrode terminal cap 8 provided with a gas discharging hole 8a, a positive temperature coefficient element(PTC element) 7d, a current shutting body 7, and an explosion-proof valve body 6 and the current shutting body 7 and the explosion-proof valve body 6 are mutually welded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safe and durable battery, and more particularly to a sealed non-aqueous secondary battery capable of maintaining its performance without damaging the inside of the battery even when a shock such as dropping is applied.

[0002]

2. Description of the Related Art In recent years, due to the high performance, miniaturization, and portability of electronic devices, the batteries used as the power source have been
Secondary batteries with high energy density have been required to replace conventional nickel-cadmium batteries and lead-acid batteries. Therefore, recently, research and development of nickel-hydrogen batteries using a hydrogen storage alloy for the negative electrode and non-aqueous secondary batteries using a substance capable of inserting and releasing light metals for the positive electrode and the negative electrode have been carried out and used for some electronic devices. Came to be. In particular, the sealed non-aqueous secondary battery that applies the insertion and release of lithium has a high battery voltage of 3.6 V and a high energy density, so the battery can be made smaller and lighter, and self-discharge is less and cycle characteristics are improved. Since it is also excellent, it is expected to be widely used as a power source for portable devices in the future.
Even if a sealed non-aqueous secondary battery such as a conventional nickel-cadmium battery or nickel-hydrogen battery is accidentally dropped, leakage of the electrolyte, change in circuit voltage, and internal resistance are small at a certain height, It is designed and manufactured so that it can be reused without impairing its performance. However, due to its high energy density, the lithium secondary battery has complicated parts such as a pressure sensitive valve body, a current interrupter, and a positive temperature coefficient of resistance element incorporated in the sealing portion, and therefore has a problem in impact resistance. There is. As a result of earnest research on the impact resistance, the present inventor has found that the explosion-proof valve body is damaged due to the movement of the electrode group due to impact,
The inventors have found that there is a problem in increasing the contact resistance of the sealing body fitted in the gasket, and have arrived at the present invention.

[0003]

SUMMARY OF THE INVENTION The present invention is a hermetically sealed structure that ensures the safety of a non-aqueous secondary battery and does not cause leakage of electrolyte solution or increase in battery resistance even when shock is applied. Type non-aqueous secondary battery.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to store an electrode group formed by winding positive and negative electrodes and a separator, an upper insulating plate and a nonaqueous electrolytic solution in a bottomed battery outer can, and to provide an insulating gasket. In a sealed non-aqueous secondary battery in which the opening of the bottomed battery outer can is closed by a sealing body fitted and supported in, the sealing body includes a positive electrode terminal cap with an exhaust hole, and a positive temperature coefficient element ( It has been solved by a sealed non-aqueous secondary battery characterized by comprising a PTC element), a current interrupting body, and an explosion-proof valve body.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The preferred embodiments of the present invention will be described below, but the present invention is not limited thereto. An electrode group formed by winding positive and negative electrodes and a separator, an upper insulating plate and a non-aqueous electrolyte are housed in a bottomed battery outer can, and the bottomed battery outer can of the bottomed battery outer can is fitted and supported by an insulating gasket. In a sealed nonaqueous secondary battery having an opening closed, the sealing body includes a positive electrode terminal cap with an exhaust hole, a positive temperature coefficient of resistance element (PTC element), a current interrupting body, and an explosion-proof valve body. A sealed non-aqueous secondary battery characterized in that Regarding the explosion-proof valve body and the current interrupter that constitute the sealing body of paragraph 1, the explosion-proof valve body is deformed to the side opposite to the electrode group side as the battery internal pressure rises, and the current interrupter is the explosion-proof valve body. And the PT
A first conductive body which is arranged between the C element and the explosion proof valve body side and has a through hole, an intermediate insulator having a through hole in the central portion, and a through hole which is arranged on the PTC element side. A sealed non-aqueous secondary battery, which is a laminated structure of three layers with a second conductor, wherein the first conductor and the second conductor are electrically connected at a central portion. Item 2. A sealed non-aqueous secondary battery, wherein the explosion-proof valve body of paragraph 2 and the first conductor of the current interrupter are welded. Item 1 to 3, wherein the explosion-proof valve body and the first conductor of the current cutoff body are made of aluminum or an alloy thereof.
The sealed nonaqueous secondary battery according to any one of 1. The upper insulating plate arranged between the electrode group and the explosion-proof valve body according to Item 1 is provided with a convex portion on the explosion-proof valve body side at a portion facing the peripheral edge of the dish-shaped body of the explosion-proof valve body, Item 5. The sealed nonaqueous secondary battery according to any one of Items 1 to 4, which has a hole. The convex portion of the closed outer periphery of the bottomed battery outer can is composed of a bottomed battery outer can, an insulating ring, and a heat-shrinkable tube covering a part of the body surface and the end surface of the battery from the outer side of the insulating ring,
Item 6 is characterized in that the step between the convex portion and the terminal cap constituting the sealing body is +1.0 to -0.5 mm with reference to the highest portion of the convex portion of the closed outer circumference of the bottomed battery outer can. The sealed nonaqueous secondary battery according to.

The present invention will be described in detail below. Although there may be various kinds of impacts, the present invention describes the resistance to impacts caused by dropping from a desk or the like, but the present invention is not limited to drop impacts. In the present invention, in order to improve the safety of the battery, the sealing body is provided with the positive electrode terminal cap with the exhaust hole, the positive temperature coefficient of resistance element (PTC element), the current interrupting body, and the explosion-proof valve body.
The positive temperature coefficient device has a function of interrupting current by increasing resistance when the temperature inside the battery rises. The current breaker is a laminated structure of a first conductor, an intermediate insulator and a second conductor,
The first conductor is arranged on the explosion-proof valve body side and has a through hole, and the second conductor is arranged on the positive temperature coefficient device side, that is, the positive electrode terminal cap side, and has a through hole. The first conductor and the second conductor are electrically connected at the central portion, and a thin portion is provided around the connection portion of the first conductor. The explosion-proof valve body can be deformed to the side opposite to the electrode group side when the internal pressure rises, and it is sufficient if it can push up the first conductor central connecting portion of the current interrupter, but especially in the vicinity of the outer peripheral portion. It is preferable that the dish-shaped body has a projecting flat portion that projects from the electrode group to the electrode group side, and that has a working body that can act on the central connecting portion of the first conductor of the current breaker when the internal pressure increases in the central portion of the projecting flat portion. Further, Japanese Patent Application No. 6-2 which integrally has a protrusion protruding toward the current interrupter at the center of the protruding flat portion.
It is preferably the explosion-proof valve body described in 94611. This explosion-proof valve body and current cutoff body, due to abnormal reaction in the battery,
When the internal pressure rises, the deformed valve body breaks the connection part between the first conductor and the second conductor of the current interrupter to interrupt the current, and when the pressure further increases, the thin part of the valve element breaks and the pressure is reduced. discharge. At this time, since the current breaker is arranged on the side opposite to the electrode group side of the explosion-proof valve body, the breakage of the battery due to the ignition of the electrolyte vapor is prevented at the breaker.

Even in the battery incorporating the above-mentioned safety mechanism, the electrode group pushes and deforms the explosion-proof valve body due to the impact such as dropping.
In some cases, the current interrupter malfunctioned or the explosion-proof valve body was damaged, resulting in liquid leakage, making it unusable. As a countermeasure against this, the explosion-proof valve body protection frame was attached to the valve body or incorporated into the sealing body, but the caulking strength of the sealing body was lowered and the suitability for the assembly process was poor. According to the present invention, a plate-shaped upper insulating plate that also serves as insulation between the electrode group and the outer can or the sealing body is arranged between the electrode group and the explosion-proof valve body, and the explosion-proof valve body side is provided near the outer periphery of the upper insulating plate. Is provided with a convex portion, and the convex portion faces the peripheral edge portion of the dish-shaped body of the explosion-proof valve body. The tip of this convex portion may be in contact with the dish-shaped body of the explosion-proof valve body. When not in contact with each other, the distance between the tip of the protrusion and the dish is preferably 1 mm or less. The upper insulating plate of the present invention has two or more holes, preferably three or more holes. At least one of the holes has a diameter of 2 mm or more, preferably 4 mm or more. In the insulating plate of the present invention having a convex portion, the central portion of the insulating plate is pushed up by the electrode group to deform the central portion of the dish-shaped body of the explosion-proof valve body to malfunction the current interrupter or damage the explosion-proof valve body. It is possible to solve the problem of causing the liquid to leak. The upper insulating plate is generally made by injection-molding resin. At that time, the rigidity of the upper insulating plate itself is formed by inserting and molding a metal ring-shaped part or the like so as to maintain insulation. It is effective to raise it. The metal to be inserted is preferably stainless steel or one with high corrosion resistance.

Since the battery of the present invention has a safety mechanism having the above-mentioned various kinds of parts built in the sealing portion, it is important to ensure continuity between the respective parts. In general, a method of laminating several kinds of sealing components in an insulating gasket and caulking and closing the sealing components with a battery outer can via the gasket is common. In order to prevent the contact resistance between parts from changing and becoming higher, these sealing bodies are designed to avoid contact between aluminum parts that originally form an oxide film having poor conductivity. In the case of using aluminum or its alloy, it is usual to use nickel or a material having good electroconductivity with nickel plating on the surface for the parts in contact with it, in order to reduce and stabilize the contact resistance between the parts.

According to the present invention, in the sealing body having a laminated structure, the portions where the sealing components made of aluminum or its alloy come into contact with each other are connected by welding so that even if an external impact such as a drop is applied, the sealing components are sealed. The resistance of is stably reduced, and the operation of the safety mechanism is made more reliable by using aluminum or its alloy. The first conductor of the explosion-proof valve body and the current interrupter to be welded is JIS standard 100
No. 0 series aluminum was used. Laser welding or ultrasonic welding is preferable as the welding means. The preferable conditions for laser welding are as follows. Voltage 250V-290V,
It is possible under the condition that the pulse width is 1 msec to 3 msec, the voltage is 260 V to 280 V, and the pulse width is 1.5 msec.
Under the condition of 2 msec, better welding strength and electrical continuity were obtained. The preferred conditions for ultrasonic welding are as follows. The welding was performed by pressing the horn from the explosion proof valve side and receiving the current interrupter side with the anvil. Welding force is 30 horn pressing force
N to 50 N, amplitude 8 μm to 12 μm, energy 5 J to 2
It was possible under the conditions of 5 J and a frequency of 40 KHz, and further better welding strength and electrical conduction were obtained under the conditions of a horn pressing force of 40 N to 50 N, an amplitude of 8 μm to 10 μm, an energy of 15 J to 25 J, and a frequency of 40 KHz.

In addition to the above, the cause of the deterioration of the battery performance due to the impact is the deformation of the negative electrode terminal cap and the accompanying deformation of the sealing body. In the present invention, these deformations are based on the convex portion on the outer periphery of the outer can closure and the step between the terminal cap and the convex portion on the outer periphery of the outer can closure (the highest position when the battery is set up) +
It was improved by changing from 1.0 mm to -0.5 mm. The step difference is more preferably +0.5 mm to −0.3 mm, +0.15
mm to 0 mm is particularly preferred. Here, “+” indicates a state where the terminal cap is protruding, and “−” indicates a state where the terminal cap is retracted. The convex curvature of the central portion of the sealing body toward the electrode group side when dropped can be made equal to or less than the step, and the increase in the resistance of the current breaker itself and the malfunction of the current breaker can be eliminated. If the step is set to +1.0 mm or more, the resistance of the current breaker itself at the time of dropping increases, and sometimes the current breaker malfunctions. If the step exceeds -0.5 mm, the connectivity with external terminals will be poor. The step has a thickness of an insulating ring placed on the convex portion on the outer periphery of the outer can closing for insulation,
It is also possible to adjust the thickness of the heat-shrinkable tube that covers a part of the body surface and the end surface of the battery from the outside of the insulating ring. If the protrusion on the outer periphery of the outer can closure is higher than the terminal cap, lead welding to the terminal cap becomes difficult. Therefore, it is desirable that the terminal cap is higher than the protrusion on the outer periphery of the outer can closure. The insulating ring is preferably paper or plastic, and polypropylene is preferable among the plastics.

The positive and negative electrodes used in the non-aqueous secondary battery of the present invention can be made by coating a positive electrode mixture or a negative electrode mixture on a current collector or molding it into pellets. The positive electrode or negative electrode mixture may contain a conductive agent, a binder, a dispersant, a filler, an ionic conductive agent, a pressure enhancer, and various additives, respectively, in addition to the positive electrode active material or the negative electrode material.

The active material in the positive electrode usable in the present invention is light.
Any material that can insert and release a metal may be used, but is preferably
A transition metal oxide containing lithium, more preferably
Li _xCoO_Two, Li_xNiO_Two, Li_xCo_aNi_1-aO_Two,
Li_xCo_bV_1-bO_z, Li_xCo_bFe_1-bO_z, Li_xM
n_TwoO_Four, Li_xMnO_Two, LiMn_TwoO_Three, Li_xMn_bCo
_2-bO_z, Li_xMn_bNi_2-bO_z, Li_xMn_bV_2-bO_z,
Li_xMn_bFe_1-bO_z(Where x = 0.05 to 1.2,
a = 0.1 to 0.9, b = 0.8 to 0.98, z = 1.
5-5). Hereinafter, the light metal referred to in the present invention is a cycle
Elements belonging to Group 1A (excluding hydrogen) and Group 2A of the table
And preferably lithium, sodium, potassium
And lithium is particularly preferable.

The active material in the negative electrode that can be used in the present invention is not particularly limited as long as it can insert and release light metals, and is preferably graphite (natural graphite, artificial graphite, vapor-grown graphite), coke (coal or petroleum). Baked organic polymer (resin or fiber of polyacrylonitrile, furan resin, cresol resin, phenol resin), mesophase pitch baked product, metal oxide, metal chalcogenide, lithium-containing transition metal oxide and chalcogenide. In particular, Ge,
Oxides and chalcogenides composed of Sn, Pb, Bi, Al, Ga, Si and Sb alone or in combination thereof are preferred. Further, it is particularly preferable to add SiO ₂ , B ₂ O ₃ , P ₂ O ₅ , Al ₂ O ₃ , V ₂ O _{5 and the} like, which are known as network forming agents, to make them amorphous. These may be of stoichiometric composition or non-stoichiometric compounds. Preferred examples of these compounds include the following, but the present invention is not limited thereto.

GeO, GeO ₂ , SnO, SnO ₂ , Sn
SiO ₃ , PbO, SiO, Sb ₂ O ₅ , Bi ₂ O ₃ , Li
₂ SiO ₃ , Li ₄ Si ₂ O ₇ , Li ₂ GeO ₃ , SnAl _0.4
B _0.5 P _0.5 K _0.1 O _3.65 , SnAl _0.4 B _0.5 P _0.5 Cs
_{0.1 O 3.65, SnAl 0.4 B 0.5} P 0.5 K 0.1 Ge 0 .05 O
_3.85 , SnAl _0.4 B _0.5 P _0.5 K _0.1 Mg _0.1 Ge _0.02 O
_3.83 , SnAl _0.4 B _0.4 P _0.4 Ba _0.08 O _3.28 , SnA
_{l 0. 5 B 0.4 P 0.5 Mg} 0.1 F 0.2 O 3.65, SnAl 0.4 B
_{0.5 P 0 .5 Cs 0.1 Mg 0.1} F 0.2 O 3.65, SnB 0.5 P 0.5
_{Cs 0. 05 Mg 0.05 F 0.1 O} 3.03, Sn 1.1 Al 0.4 B 0.4 P
_{0.4 Ba 0 .08 O 3.34, Sn} 1.2 Al 0.5 B 0.3 P 0.4 Cs
_0.2 O _3.5 , SnSi _0.5 Al _0.2 B _0.1 P _0.1 Mg
_{0.1 O 2.8, SnSi 0 .5 Al} 0.3 B 0.4 P 0.5 O 4.30, S
_{nSi 0.6 Al 0.1 B 0. 1 P} 0.1 Ba 0.2 O 2.95, SnSi
_0.6 Al _0.4 B _0.2 Mg _0.1 O _3.2 , Sn _0.9 Mn _0.3 B _{0.4
P 0.4 Ca 0.1 Rb 0.1 O 2} .95, Sn 0.9 Fe 0.3 B 0.4 P
_0.4 Ca _0.1 Rb _0.1 O _2.95 , Sn _0.3 Ge _0.7 Ba _0.1 P
_0.9 O _3.35 , Sn _0.9 Mn _0.1 Mg _0.1 P _0.9 O _3.35 , Sn
_0.2 Mn _0.8 Mg _0.1 P _0.9 O _3.35 .

Further, the anode material of the present invention can be used by inserting a light metal, particularly lithium. The method of inserting lithium is preferably an electrochemical, chemical or thermal method.

The amount of lithium inserted into the negative electrode material of the present invention is:
It may be up to approximation of the deposition potential of lithium, but is preferably 50 to 700 mol% per the above-mentioned preferable negative electrode material.
Particularly, 100 to 600 mol% is preferable.

The conductive agent in the positive electrode and the negative electrode which can be used in the present invention is graphite, acetylene black, carbon black, Ketjen black, carbon fiber or metal powder, metal fiber or polyphenylene derivative, and graphite and acetylene black are particularly preferable. . The binder in the positive electrode and the negative electrode that can be used in the present invention is polyacrylic acid, carboxymethylcellulose, polytetrafluoroethylene,
Polyvinylidene fluoride, polyvinyl alcohol, starch,
Regenerated cellulose, diacetyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, polyvinyl pyrrolidone, polyethylene, polypropylene, SBR, E
PDM, sulfonated EPDM, fluororubber, polybutadiene, and polyethylene oxide, with polyacrylic acid, carboxymethylcellulose, polytetrafluoroethylene, and polyvinylidene fluoride being particularly preferred.

The support or current collector for the positive electrode and the negative electrode that can be used in the present invention is made of aluminum, stainless steel, nickel, titanium, or an alloy thereof for the positive electrode, and copper, stainless steel, or the like for the negative electrode. Nickel, titanium,
Or, these are alloys, and are in the form of foil, expanded metal, punching metal, or wire mesh. Especially,
Aluminum foil is preferable for the positive electrode, and copper foil is preferable for the negative electrode. The separator that can be used in the present invention has a high ion permeability, a predetermined mechanical strength, and may be an insulating thin film. As the material, olefin polymer, fluorine polymer, cellulose polymer, polyimide, nylon,
Glass fibers and alumina fibers are used, and as a form, a nonwoven fabric, a woven fabric, or a microporous film is used. In particular, the material is preferably polypropylene, polyethylene, a mixture of polypropylene and polyethylene, a mixture of polypropylene and Teflon, a mixture of polyethylene and Teflon, and the form is preferably a microporous film.
In particular, a microporous film having a pore size of 0.01 to 1 μm and a thickness of 5 to 50 μm is preferable.

The electrolyte that can be used in the present invention is an organic solvent.
Then propylene carbonate, ethylene carbonate,
Butylene carbonate, dimethyl carbonate, diethyl
Rucarbonate, 1,2-dimethoxyethane, γ-buty
Lolactone, tetrahydrofuran, 2-methyltetrahi
Drofuran, dimethyl sulfoxide, dioxolan,
1,3-dioxolan, formamide, dimethylform
Amide, nitromethane, acetonitrile, methyl formate,
Methyl acetate, methyl propionate, phosphoric acid triester,
Trimethoxymethane, dioxolane derivative, sulfora
, 3-methyl-2-oxazolidinone, propylene carbonate
Carbonate derivative, tetrahydro derivative, diethyl ether
At least one of tel and 1,3-propane sultone
Mixed with LiClO as an electrolyte_Four, L
iBF_Four, LiPF₆, LiCF_ThreeSO_Three, LiCF_ThreeC
O_Two, LiAsF₆, LiSbF₆, LiB_TenCl_Ten, Low
-Grade aliphatic lithium carboxylate, LiAlCl_Four , LiC
l, LiBr, LiI, chloroborane lithium, tetraphenyl
A solution in which one or more salts of lithium nilborate are dissolved is preferred.
Good. Especially propylene carbonate or ethylene
Carbonate and 1,2-dimethoxyethane and / or
Is LiCF in a mixed solvent with diethyl carbonate _ThreeS
O_Three, LiClO_Four, LiBF_Four, And / or LiP
F₆It is preferable that at least ethylene is dissolved.
Ren carbonate and LiPF₆ It is preferable to include

The shape of the battery can be applied to any of buttons, coins, sheets, cylinders, corners and the like. For buttons and coins, the mixture is press-formed into pellets, and for sheets, squares and cylinders, the mixture is coated on a current collector, dried, dehydrated, and pressed. A battery is formed by inserting an electrode wound with a pellet, a sheet, or a separator into a battery can, electrically connecting the can and the electrode, injecting an electrolyte, and sealing the battery. It is preferable that the battery is provided with a current cutoff mechanism and an internal pressure release explosion-proof valve body as means for ensuring safety even in the case of malfunction.

The bottomed battery outer can that can be used in the present invention is made of nickel-plated iron steel plate or stainless steel plate (SUS304, SUS304L, SUS304).
N, SUS316, SUS316L, SUS430, S
US444, etc.), nickel-plated stainless steel plate (same as above), aluminum or its alloy, nickel,
They are titanium and copper, and have a shape of a perfect circular cylinder, an elliptical cylinder, a square cylinder, or a rectangular cylinder. In particular, when the outer can also serves as the negative electrode terminal, a stainless steel plate or a nickel-plated iron steel plate is preferable, and when the outer can also serves as the positive electrode terminal, a stainless steel plate, aluminum or an alloy thereof is preferable.

The gasket which can be used in the present invention is made of olefin polymer, fluorine polymer, cellulose polymer, polyimide or polyamide. Olefin polymer is preferable in view of organic solvent resistance and low moisture permeability. Propylene-based polymers are preferred. Further, it is preferably a block copolymer of propylene and ethylene.

[0023] The battery of the present invention is covered with an exterior material as required. Examples of the exterior material include a heat-shrinkable tube, an adhesive tape, a metal film, paper, cloth, paint, a plastic case, and the like. Further, at least a part of the exterior may be provided with a portion that changes color by heat so that the heat history during use can be recognized. A plurality of batteries of the present invention are assembled in series and / or in parallel and stored in a battery pack as needed. In addition to safety elements such as positive temperature coefficient resistors, thermal fuses, fuses and / or current interrupting elements, battery packs have safety circuits (voltage, temperature, current, etc. of each battery and / or assembled battery as a whole, Then, a circuit having a function of interrupting the current may be provided. In addition to the positive and negative terminals of the whole battery pack, the positive and negative terminals of each battery, the temperature detection terminals of the whole battery pack and each battery, the current detection terminals of the whole battery pack, etc. shall be provided as external terminals on the battery pack. Can also. The battery pack may have a built-in voltage conversion circuit (such as a DC-DC converter). The connection of each battery may be fixed by welding a lead plate, or may be fixed by a socket or the like so that it can be easily detached. Further, the battery pack may be provided with a display function of the remaining battery capacity, the presence / absence of charging, the number of times of use, and the like.

The battery of the present invention is used for various devices.
In particular, video movies, portable VCRs with monitors, movie cameras with monitors, compact cameras,
SLR camera, disposable camera, film with lens, notebook computer, notebook word processor, electronic organizer,
It is preferably used for mobile phones, cordless phones, beards, electric tools, electric mixers, automobiles and the like.

[0025]

The present invention will be described in more detail with reference to specific examples, but the present invention is not limited to the examples unless it exceeds the gist of the invention. First, how to make an electrode will be described, and then how to assemble a battery will be described. SnB _0.2 P _0.5 K _0.1 Mg _0.1 Ge _0.1 O _2.
8 86 parts by weight, were mixed at a ratio of 3 parts by weight of acetylene black and 6 parts by weight of graphite as a conductive agent, polyvinylidene fluoride 4 parts by weight and carboxymethylcellulose is further aqueous dispersion of 0.2μ as a binder 1 part by weight was added and kneaded with water as a medium to obtain a slurry. The slurry was applied on both sides of a copper foil having a thickness of 10 μm by using an extrusion type coating machine, dried and then compression-molded by a calendar press machine to prepare a strip-shaped negative electrode. 87 parts by weight of LiCoO2 as a positive electrode active material, 3 parts by weight of acetylene black as a conductive agent and 6 parts by weight of graphite were mixed, and further 3 parts by weight of Nipol820B (manufactured by Zeon Corporation) and carboxymethylcellulose 1 as a binder.
By weight, water was used as a medium and kneaded to obtain a slurry. The slurry was applied on both sides of an aluminum foil having a thickness of 20 μm by using an extrusion type coating machine, dried and then compression-molded by a calendar press machine to prepare a strip-shaped positive electrode.

After the lead plates made of nickel and aluminum were welded to the ends of each of the negative electrode and the positive electrode, heat treatment was performed at 230 ° C. for 1 hour in dry air having a dew point of −40 ° C. or less. The heat treatment was performed using a far infrared heater. Further, a heat-treated positive electrode, a microporous polyethylene / polypropylene film separator, a heat-treated negative electrode, and a separator were laminated in this order, and were spirally wound. The wound body was housed in a bottomed cylindrical battery can made of iron plated with nickel and serving also as a negative electrode terminal. Further, 1 mol / liter LiPF ₆ (mixed solution of ethylene carbonate and diethyl carbonate in a weight ratio of 2 to 8) was injected into the battery can as an electrolyte. A battery cover having a positive electrode terminal was caulked via a gasket to produce a cylindrical battery. The positive electrode terminal was connected to the positive electrode and the battery can was connected to the negative electrode by a lead terminal in advance.

Comparative Battery To confirm the effect of the present invention, a comparative sealed non-aqueous secondary battery not incorporating the present invention was manufactured by the following procedure. This will be described below with reference to FIG. The comparative battery has a positive electrode (2a) and a negative electrode (2a)
b) and are wound via a separator (2c), and the electrode group wound with a polypropylene-based acrylic adhesive tape is attached to the top and bottom of the plate to form a polypropylene plate having a hole of polypropylene with a thickness of 0.3 mm. The insulator (3a) is placed in the outer can (1) with an outer diameter of about 16.5 mm together with the non-aqueous electrolyte, and the opening of the outer can is coated with asphalt to form a plurality of sealing parts. It was manufactured by arranging a sealing body consisting of and caulking the outer can inside and closing and sealing. The total height of the battery after caulking was set to about 670 mm.
To prevent short circuit outside the sealing part, a polypropylene ring (10) for insulation is placed on the convex part on the outer periphery of the outer can closure, and a part of the battery body surface and end surface is cross-linkable from the outside. It was covered with a polyethylene heat shrink tube (11). At this time, an insulating ring placed on the convex portion of the outer periphery of the outer can closure and a terminal cap including the thickness of the heat-shrinkable tube covering a part of the body surface and the end surface of the battery from the outer side of the insulating ring, The step (15 in FIG. 7) was +1.2 mm.

Battery A Battery A is an embodiment of a battery manufactured by ensuring the electrical connection between the explosion-proof valve body and the current interrupter of the present invention. As shown in Fig. 2, while the explosion-proof valve body (6) and the current cut-off body (7) are superposed on each other, both are pressed by JIS standard 1000
The outer periphery of the No. 1 aluminum explosion-proof valve body and the first conductor (7a) of the current interrupter was two-point welded with a YAG laser welder. The welding of this embodiment was carried out under the conditions of a voltage of 280 V and a pulse width of 1.5 msec, at which particularly good welding strength and electrical continuity were obtained. A battery was manufactured in the same procedure as that of the comparative battery except that the welded explosion-proof valve body and the current interrupter were incorporated.

Battery A'Battery A'is another embodiment of the battery manufactured by ensuring the electrical connection between the explosion-proof valve body and the current interrupter of the present invention. FIG.
As shown in Fig. 2, after the explosion-proof valve body and the current cutoff body were superposed, two points of the vicinity of the outer periphery of the JIS standard No. 1000 series aluminum explosion-proof valve body and the first conduction body of the current cutoff body were ultrasonically welded together. . The welding used in this embodiment was a horn pressing force of 40 N and an amplitude of 9 μ, which gave particularly good welding strength and electrical continuity.
m, energy 15 J, and frequency 40 KHz. A battery was manufactured in the same procedure as the comparative battery except that the welded explosion-proof valve body and the current interrupter were incorporated.

Battery B Battery B is an embodiment of a battery manufactured by incorporating an upper insulating plate having a convex portion in the vicinity of the outer peripheral portion of the present invention. FIG. 4 shows the upper insulating plate used in this example, and FIG. 5 is a view showing the upper insulating plate incorporated in a battery. The upper insulating plate (3
The outer shape of b) is 15 mm, and the convex part is 1.5 mm from the outer circumference.
The width is 1 mm at a position of mm to 2.5 mm, the height is 1.5 mm from the bottom surface of the upper insulating plate, and the distance to the opposing explosion-proof valve body is 0 mm to 0.5 mm at the convex portion. The upper insulating plate of FIG. 4 was manufactured by injection molding polypropylene. A battery was manufactured in the same procedure as the comparative battery except that the upper insulating plate shown in FIG. 4 was incorporated.

Battery B'Battery B'is another embodiment of a battery manufactured by incorporating an upper insulating plate having a convex portion in the vicinity of the outer periphery of the present invention. FIG.
Is an upper insulating plate used in the present embodiment. In order to increase the rigidity of the upper insulating plate, an outer shape 11 made of SUS316L is formed so as not to impair the insulating property of the surface facing the electrode group inside the upper insulating plate.
A ring having a diameter of 5 mm, an inner diameter of 5 mm and a thickness of 0.3 mm is inserted and injection-molded. It was manufactured in the same shape as the upper insulating plate of the battery B except that a metal ring was inserted. A battery was manufactured in the same procedure as the comparative battery except that the upper insulating plate shown in FIG. 6 was incorporated.

Battery C Battery C is an embodiment of a battery adopting the relationship between the convex portion on the outer periphery of the outer can closing and the step difference of the terminal cap according to the present invention. FIG. 7 shows the relationship between the steps in this embodiment. The insulating ring placed on the outer peripheral closed convex portion of the outer can is made of polypropylene and has an outer diameter of 15 mm, an inner diameter of 9 mm and a thickness of 0.5 mm. The heat-shrinkable tube that covers a part of the body surface and the end surface of the battery from the outside of the insulating ring is made of crosslinkable polyethylene, and the thickness after heat-shrinking is 0.15 mm. After mounting the insulating ring and the heat-shrinkable tube, the height difference between the terminal cap and the convex portion on the outer periphery of the outer can closed is +0.08 mm, and the terminal cap is exposed. Figure 7
A battery was manufactured in the same procedure as that of the comparative battery, except that the difference in level was formed.

Battery BC The battery BC is an embodiment of a battery which employs the relationship between the upper insulating plate of the battery B, the convex portion of the outer can of the battery C, and the step of the terminal cap. A battery was manufactured in the same procedure as that of the comparative battery except that the upper insulating plate of the battery B was incorporated and the step of the battery C was formed.

Battery ABC The battery ABC incorporates the laser-welded explosion-proof valve body of the battery A and the current breaker, and the relation between the upper insulating plate of the battery B, the convex portion of the outer can closure of the battery C and the step of the terminal cap. It is an example of a battery adopting. A battery was manufactured in the same procedure as that of the comparative battery, except that the explosion-proof valve body of the battery A, the current interrupter, and the upper insulating plate of the battery B were incorporated, and the step was the same as that of the battery C.

Battery A, battery A ', battery B of the above embodiment,
Battery B ', battery C, battery BC, battery ABC and 50 comparison batteries each were manufactured and subjected to a drop test. 90 drop tests
From the height of cm to the tile, the battery terminal cap is on the tile, the outer can bottom is on the bottom, and the body surface is on the bottom. evaluated. Regarding the change in battery resistance, a battery whose resistance increased by 10 mΩ or more before and after the drop was judged to be abnormal. Regarding the leakage, the battery in which the leakage of the electrolyte could be visually confirmed after dropping was judged to be abnormal. The results of the drop test are shown in Table 1.

[0036]

[Table 1]

In the batteries A and A ', welding of the explosion-proof valve member and the current interrupter could significantly suppress the resistance change of the battery due to drop impact. In the batteries B and B ′, the upper insulating plate of the present invention protects the explosion-proof valve body from the impact of the electrode group at the time of dropping, and increases the resistance of the current interrupter, malfunctions of the current interrupter, and leakage due to damage of the explosion-proof valve. The liquid could be prevented. It is understood that the relationship between the convex portion on the outer periphery of the closed outer can of the battery C and the step difference of the terminal cap does not contribute so much to the suppression of the battery resistance change. Is 0.08 mm
Below, the deformation amount of the terminal cap of the comparative battery is 0.8 mm
Since it is ~ 1.1 mm, the increase in the resistance of the current interrupter presumably caused by the impact from the terminal cap side at the time of dropping,
It is considered to be effective in preventing malfunction of the current breaker.
In the battery BC, it was possible to prevent an increase in the resistance of the current breaker and a malfunction of the current breaker due to the deformation of the explosion-proof valve body and the terminal cap. In the case of the battery ABC, the resistance change of the battery before and after the drop was 10 mΩ or less even when a shock was applied by dropping, and the leakage of the electrolytic solution was completely eliminated.

As is clear from the above results, the sealed non-aqueous secondary battery of this example has a small resistance change before and after the drop even when a shock is applied in the drop test, and does not cause leakage of the electrolytic solution. . The sealed non-aqueous secondary battery of this example could be used without problems even after the drop test.

[0039]

As described above, the present invention can provide a sealed non-aqueous secondary battery in which the resistance change is small and liquid leakage does not occur even when an impact such as a drop is applied. The sealed non-aqueous secondary battery of the present invention can be reused after being dropped if the height is about 90 cm.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a sealed non-aqueous secondary battery of the present invention.

FIG. 2 is an example of the electrical connection between the explosion-proof valve body and the current cutoff body of the present invention, in which the first conductor of the explosion-proof valve body and the current cutoff body is laser-welded.

FIG. 3 is an example of the electrical connection between the explosion-proof valve body and the current cutoff body of the present invention, in which the first conductor of the explosion-proof valve body and the current cutoff body is ultrasonically welded.

FIG. 4 is an example of an upper insulating plate arranged between the electrode group and the explosion-proof valve body of the present invention.

FIG. 5 is a sectional view of a battery incorporating the upper insulating plate of the present invention.

FIG. 6 is an example of an upper insulating plate of the present invention, in which a metal ring is inserted into the upper insulating plate and injection molding is performed.

FIG. 7 is a diagram showing the relationship between the convex portion on the outer periphery of the outer can closure and the step of the terminal cap of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 outer can 2 electrode group 2a positive electrode 2b negative electrode 2c separator 3a upper insulating plate (conventional) 3b upper insulating plate (present invention) 4 lead plate 5 gasket 6 explosion-proof valve body 7 current breaker 7a first conducting body 7b second conducting body 7c Intermediate Insulator 7d Positive Temperature Coefficient Resistor (PTC Element) 8 Terminal Cap 8a Exhaust Hole 9 Grooved Thin Section 10 Exterior Insulation Ring 11 Exterior Tube 12 Laser Weld 13 Ultrasonic Welding Section 14 Metal Ring 15 Exterior Can Closing Outer Perimeter Step between the convex part and the terminal cap

Claims (6)

[Claims] 1. An electrode group formed by winding positive and negative electrodes and a separator, an upper insulating plate and a nonaqueous electrolytic solution are housed in a bottomed battery outer can, and are sealed by a sealing body fitted and supported by an insulating gasket. In a sealed nonaqueous secondary battery in which an opening of a bottom battery outer can is closed, the sealing body includes a positive electrode terminal cap with an exhaust hole, a positive temperature coefficient of resistance element (PTC element),
A sealed non-aqueous secondary battery comprising a current interrupter and an explosion-proof valve. 2. An explosion-proof valve body and a current interrupting body constituting the sealing body according to claim 1, wherein the explosion-proof valve body is deformed to the side opposite to the electrode group side as the internal pressure of the battery rises, and the current interrupting body Is a first conducting body which is arranged between the explosion-proof valve body and the PTC element and which is arranged on the explosion-proof valve body side and has a through hole; an intermediate insulator having a through hole in a central portion; and the PTC element. It is a laminated structure of three layers with a second conductive body disposed on the side and having a through hole, wherein the first conductive body and the second conductive body are electrically connected at a central portion. Sealed non-aqueous secondary battery. 3. A sealed non-aqueous secondary battery, wherein the explosion-proof valve body according to claim 2 and the first conductor of the current interrupter are welded together. 4. The sealed nonaqueous secondary battery according to claim 1, wherein the explosion-proof valve body and the first conductor of the current interrupter are made of aluminum or an alloy thereof. . 5. The upper insulating plate arranged between the electrode group and the explosion-proof valve body according to claim 1 has a convex portion on the explosion-proof valve body side at a portion facing a peripheral portion of the dish-shaped body of the explosion-proof valve body. The sealed nonaqueous secondary battery according to claim 1, wherein the sealed nonaqueous secondary battery is provided and has a plurality of holes. 6. The convex portion of the closed outer periphery of the bottomed battery outer can is formed from a heat-shrinkable tube that covers the bottomed battery outer can, the insulating ring, and a part of the body surface and end surface of the battery from outside of the insulating ring. The step difference between the convex portion and the terminal cap forming the sealing body is +1.0 to −0.5 mm with reference to the highest portion of the convex portion on the closed outer circumference of the bottomed battery outer can. The sealed nonaqueous secondary battery according to claim 6.