JPH09129209A - Organic electrolytic battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily prevent fire produced in overdischarge, surely obstruct electrolyte leakage, and enhance reliability by arranging a sealing body comprising a dish-like sealing plate, a circular PTC element plate and a cap, etc. SOLUTION: A sealing body comprising a dish-like sealing plate 8c formed by caulking the periphery part of a valve body 8b to a valve port, a circular PTC element plate 8d formed by cutting out a part corresponding to the valve body 8b and arranged by stacking on the peripheral flat surface of the plate 8c, and a cap 8e is arranged. The valve body 8b is caulked in its periphery part and melt-bonded or stuck with an adhesive to the plate 8c. By interposing the plate 8d between the peripheral flat surface of the plate 8c and the peripheral flat surface of the cap 8e, the deformation caused by caulking fixing is eliminated or avoided, overheating and firing of the battery in overdischarge can be prevented. By firmly fixing the valve body 8b to the valve port of the plate 8c by caulking, peeling off is prevented and airtightness is held even in high temperature storage, and electrolyte leakage can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electrolyte battery having an organic electrolyte-based battery power generating element built therein, and more specifically, to improve the safety and reliability by improving the structure of the sealing portion. And an organic electrolyte battery.

[0002]

2. Description of the Related Art In recent years, as a non-aqueous electrolyte battery, an organic electrolyte battery using a light metal such as lithium or sodium as a negative electrode has been attracting attention as a battery having high voltage, high energy density and long-term reliability. For example, the lithium primary battery property, in which manganese dioxide (MnO ₂ ) and fluorocarbon (CF ₂ ) _n are used as the positive electrode active material, is often used as a power source for cameras, calculators, watches and backup batteries for memories.

On the other hand, with regard to the secondary battery incorporated in various equipment systems such as a mobile phone and a portable image pickup device and used as an operating power source, the portable phone and the portable image pickup device are made smaller and lighter. Accordingly, a secondary battery having a high energy density is required as a power source, and in response to this demand, the development of an organic electrolyte secondary battery having a negative electrode such as lithium is in progress. In this type of organic electrolyte secondary battery, (a) the negative electrode is lithium, and (b) the lithium ion conductive electrolyte is propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, γ-butyrolactone,
In an organic solvent such as tetrahydrofuran, for example LiC
An organic electrolyte (non-aqueous electrolyte) formed by dissolving a lithium salt such as l0 ₄ , LiBF ₄ , LiAsF ₆ , or LiPF ₆ or a lithium ion conductive solid electrolyte is (c) mainly vanadium as a positive electrode active material. Compounds that participate in the topochemical reaction with lithium, such as oxides, cobalt oxides, and manganese oxides, are used.

By the way, the above-mentioned organic electrolyte battery is required to have stable hermeticity and airtightness for a long period of time, and a sealing structure having a high hermeticity is being developed. The high degree of airtightness of the sealing structure poses a problem in terms of safety against internal short circuit or external short circuit of the battery, or over discharge, that is, when gas is generated inside the battery due to the short circuit or over discharge. The internal pressure of the battery rises due to the airtightness, and the outer can and the like may be broken or ruptured.

In order to prevent the above-mentioned safety problem from interrupting the current at the time of short circuit or over-discharge and preventing the rise of the battery internal pressure, the PTC element is arranged in the conductive circuit of the battery sealing part, while It is known that a thin valve element is provided at the battery sealing part in order to avoid gas explosion and damage by damaging the battery and releasing gas inside the battery (Japanese Utility Model Publication No. 2-50957, etc.). FIG. 5 shows one countermeasure, in which 1 is an outer can that also serves as a negative electrode terminal in which an organic electrolyte-based battery power generation element 2 is incorporated, 3
Is a sealing body that doubles as a positive electrode terminal for hermetically sealing the opening of the outer can 1 in which the battery power generating element 2 is mounted by caulking with an insulating packing material 4. Here, the sealing body 3 includes a plate-shaped sealing plate 3d having a flat peripheral portion in which the peripheral portions of the valve body 3b and the spacer 3c corresponding to the valve opening 3a provided in the central portion are fixed by caulking, and the plate-shaped sealing plate 3d. An annular PTC with a portion corresponding to the valve body 3b located on the flat surface around
The element plate 3e and the peripheral flat portion are laminated on the surface of the PTC element plate 3e, and a region corresponding to the valve body 3b of the dish-shaped sealing plate 3d is provided in a protruding manner, and the protruding portion has a cutting edge 3f ′ and It comprises a cap 3f provided with a gas vent hole 3f ″. Reference numeral 5 is a lead piece for electrically connecting the sealing body 3 and the positive electrode side of the battery power generating element 2.

FIG. 6 is a cross-sectional view of the main part of another configuration example. The cross-sectional shape of the sealing plate 3d 'is the same as that of the cap 3f, with the central portion protruding so that both peripheral portions are flat. An annular PTC element plate 3e is directly inserted between the surfaces.
That is, the valve body 3b is attached to the outside of the protruding portion of the sealing plate 3d 'to close the valve mouth 3a, while the insulating spacer 3c' is attached between the valve body 3b and the inner wall surface of the cap 3f to sandwich the valve body 3b. The PTC element plate 3e is inserted between the flat peripheral surfaces of the sealing plate 3d 'and the cap 3f, and the rising edge of the peripheral edge of the sealing plate 3d' is capped with another insulating spacer 3c ".
The structure is the same as that shown in FIG. 5 except that the periphery of 3f is fixed by crimping.

The ring-shaped PTC element plate 3e is usually
The conductive resin layer 3 is shown in FIG.
It has a structure in which e ′ is integrally sandwiched by a thin metal plate 3e ″. Then, a conductive resin layer is formed by a current during short circuit or discharge.
3e ′ generates heat and expands, and its resistance value increases, thereby interrupting the current and functioning to prevent an increase in battery internal pressure.

[0008]

However, while the current in the short circuit or overdischarge is interrupted to prevent the internal pressure of the battery from rising, measures are taken to prevent the explosion and damage by discharging the upper pressurized gas in the battery. Even if it is adopted, there are still the following problems. For example, if over-discharged with a current of 1 A or more, P
The discharge current is interrupted by the heat generated by the TC element 3e, but Fig. 5
In the case of the configuration shown in Fig. 6, since local pressure is applied to the PTC element 3e, if the heat generation of the PTC element continues for a long time, the caulking fixing part of the PTC element 3e is shown in cross section in FIG. There is a risk of deformation in the vicinity. The deformation of the PTC element 3e in the vicinity of the crimping fixing part is caused by the thin metal plate 3
Since it causes contact (short circuit / conduction) between e ″ and loses the current interruption function, overheating and ignition of the battery may occur, or even if ignition does not occur, the valve body 3b may be cleaved and the internal There is a problem that the electrolyte leaks.

Incidentally, FIG. 9 shows an example of characteristics in an overdischarge test of the primary battery having the structure shown in FIG. To solve such a problem, in the configuration shown in FIG. 5, a metal reinforcing plate is inserted and arranged between the stacking surfaces of the sealing plate 3d and the PTC element 3e, and local pressure applied to the PTC element 3e by caulking is fixed. It has also been attempted to disperse the PTC elements 3e to prevent deformation. However, the insertion of metal reinforcement plate
The arrangement increases the number of parts and the volume of the sealing body 3,
This is an obstacle to cost reduction and battery compaction.

In the case of the configuration shown in FIG. 6, the PTC
Since the element 3e is entirely sandwiched between the sealing plate 3d 'and the flat surface portion of the cap 3f, deformation due to caulking fixation is eliminated or avoided, and problems such as battery overheating and ignition are completely eliminated. However, the attachment of the valve body 3b is not sufficient, and for example,
When stored at a high temperature of about 80 ° C, the valve body 3b is closed with the sealing plate 3d ′.
There is a problem that the insulating spacer 3c 'that presses against the surface is deformed, the valve body 3b is peeled off even if the internal pressure of the battery is slightly increased, and the electrolyte leaks.

The present invention has been made in view of such circumstances, and while aiming at cost reduction and downsizing, it is possible to easily prevent ignition occurring at the time of over-discharging and surely prevent leakage of the electrolytic solution. An object of the present invention is to provide a highly reliable organic electrolyte battery.

[0012]

According to a first aspect of the present invention, an outer can, which also functions as a negative electrode terminal, in which an organic electrolyte-based battery power generating element is housed, and an opening of the outer can are provided with an insulating packing material. A sealing body that also functions as a positive electrode terminal that hermetically seals by caulking, a lead piece that electrically connects the sealing body and the positive electrode side of the battery power generation element, and a part of the conductive circuit between the positive electrode terminal and the lead piece. In the organic electrolyte battery having a PTC element, the sealing body includes a flat plate-shaped sealing plate with a peripheral edge portion of the valve body attached to the valve opening provided at the center by caulking, and the valve. The part corresponding to the body is cut out, and the annular PTC element plate stacked on the flat peripheral surface of the dish-shaped sealing plate and the region corresponding to the valve body project, and the cutting blade and the vent hole are projected on this projecting part. A flat plate around the plate-shaped sealing plate Parts is an organic electrolyte battery characterized in that it forms a structure in which and a cap which are stacked through the PTC element.

In the present invention, as the positive electrode, for example, active material such as manganese dioxide or fluorocarbon is applied to the surface of the positive electrode current collector, expanded metal or punched metal plate, expanded metal. And so on.

Further, examples of the negative electrode include metallic lithium foil and metallic sodium foil.

Examples of organic electrolytes usable in the present invention include ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, sulfolane, acetonitrile, 1,2-dimethoxymethane, 1,3-dimethoxypropane, dimethyl ether, Lithium perchlorate (LiClO ₄ ) in an organic solvent (non-aqueous solvent) consisting of at least one selected from the group of tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl carbonate, diethyl carbonate and ethylmethyl carbonate, methylpropionate, Lithium hexafluorophosphate (LiP
F ₆ ), lithium borofluoride (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ) and other lithium salts (electrolytes)
An organic electrolytic solution in which about 0.3 to 1.5 mol / l is dissolved is generally mentioned. Instead of the non-aqueous electrolyte solution, an ion conductive solid electrolyte, for example, a polymer solid electrolyte obtained by compounding a lithium salt with a polymer compound may be used.

Further, as the separator for insulating and separating the negative electrode and the positive electrode, for example, a nonwoven fabric of polyolefin resin such as polyethylene or polypropylene or a porous film can be used.

According to the first aspect of the invention, since the PTC element plate is entirely sandwiched between the flat peripheral surface of the plate-shaped sealing plate and the flat peripheral surface of the cap, deformation due to caulking is eliminated or avoided, resulting in overcurrent. At times, problems such as overheating and ignition of the battery are completely eliminated, and stable battery operation is easily realized.
In addition, the valve body is firmly fixed and held by caulking at the valve mouth of the dish-shaped sealing plate, so it does not peel off even when stored at a high temperature of about 80 ° C, ensuring airtightness. Since it is held, there is no risk of electrolyte leaking out, and the battery functions as a highly reliable battery.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a sectional view showing the structure of the essential parts of an organic electrolyte battery according to an embodiment of the present invention. In FIG. 1, 6
Is an iron outer can that also serves as a negative electrode terminal in which an organic electrolyte-based battery power generating element 7 is incorporated, and 8 is an insulating packing material 9 made of synthetic resin in the opening of the outer can 6 in which the battery power generating element 7 is incorporated.
It is a sealing body which also functions as a positive electrode terminal which is hermetically sealed by caulking via. Further, 10 is a lead piece for electrically connecting the sealing body 8 and the negative electrode side of the battery power generating element 7.

In the above structure, the battery power generating element 7 is a negative electrode material made of, for example, metallic lithium foil, for example, a positive electrode material made by coating manganese dioxide on an expanded metal surface forming a base material, for example, a porous polypropylene resin. Wound body (winding body) made of a membrane separator
Is impregnated with an organic electrolytic solution using, for example, ethylene carbonate as a solvent. Furthermore, the sealing body 8
Corresponds to the plate-shaped sealing plate 8c made of, for example, stainless steel, which has a peripheral portion of the valve body 8b fixed to the valve opening 8a provided in the central portion (low wall surface) by caulking, and the valve body 8b. A portion is cut out, an annular PCT element plate 8d stacked on the peripheral flat surface of the dish-shaped sealing plate 8c, and a region corresponding to the valve body 8b are projected, and a cutting edge 8e ′ is formed on this protruding portion. And a gas vent hole 8e ″, and a flat peripheral portion on the flat peripheral surface of the dish-like sealing plate 8c, with the peripheral flat portion being laminated and arranged through the PTC element, the cap 8e.
And is configured to include.

The valve body 8b is formed by laminating, for example, an aluminum foil and a modified polypropylene resin film or a polyethylene sheet, and the peripheral portion thereof is not only fixed by caulking but also heat-sealed to the surface of the dish-shaped sealing plate 8c or It is attached with an adhesive. When the valve body 8b is attached to the valve mouth 8a portion of the dish-shaped sealing plate 8c by caulking, it is necessary to be careful not to damage the valve body 8b due to burrs or the like generated when the valve mouth 8a is cut out. is there. Figure 2
As schematically shown in (a) and (b), using the required mold 11, the thin plate piece 12 made of stainless steel provided with the valve opening 8a and the valve body 8b are arranged and mounted to form the thin plate. When mounting the peripheral edge of the valve body 8b by crimping while bending the piece 12, burring processing 12a is performed on the inner peripheral surface of the valve opening 8a of the thin plate piece 12, or instead of the burring processing 12a,
As shown in a sectional view in FIG. 3, it is desirable to deform the valve body 8b into a convex shape.

Table 1 shows the results of an over-discharge test (test number: 10) and a storage test at 80 ° C. (test number: 100) with the current value of 1 A for the organic electrolyte battery having the above structure. Show. Further, FIG. 4 shows an example of characteristics in the overdischarge test.

On the other hand, for the sake of comparison, the organic electrolyte solution batteries whose main components are shown in FIG. 5 (Comparative Example 1) and FIG. 6 (Comparative Example 2) are also set to a current value of 1 A. The results of the overdischarge test and the storage test at 80 ° C. are shown in Table 1 together. Further, FIG. 9 shows a characteristic example in the over-discharge test of Comparative Example 1.

Table 1 Number of ignitions during overdischarge test Number of leaks during storage at 80 ° C Example 0/10 0/100 Comparative example 1 5/10 0/100 Comparative example 2 0/10 10/100 Clear from the above test As described above, in the case of the organic electrolyte batteries according to the examples, neither ignition during the overdischarge test nor leakage of the electrolyte during the 80 ° C. storage test was observed. On the contrary,
As a result of disassembling and investigating the organic electrolyte battery of Comparative Example 1 in which an abnormality occurred in the overdischarge test, local pressure deformation of the PTC element plate was recognized, and the metal plates were directly connected to each other, and the required blocking action was obtained. It was confirmed that it did not exhibit. on the other hand,
As a result of disassembling and investigating the organic electrolyte battery of Comparative Example 2 in which the electrolyte leaked during the 80 ° C. storage test, it was confirmed that the valve body of the sealing body was peeled off and the airtightness was impaired.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention. For example, the components of the positive electrode and the negative electrode and the components of the separator are
Even if the known positive electrode, separator, etc. are changed, the same action and effect can be obtained.

[0026]

As described above, according to the organic electrolytic solution battery of the present invention, even in continuous heat generation for a long time,
Since the failure of the PTC element that functions to cut off the current is completely avoided, there is no danger of ignition such as during over-discharge, and it functions as a highly safe battery. Also, in normal use, it exhibits excellent airtightness and there is no risk of problems such as electrolyte leakage, and the required power generation (electromotive force) is maintained, so it should function as a highly reliable battery. become. In other words, it is possible to provide a power source that supports the reliability and compactness of portable electronic devices.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view showing a configuration example of a main part of an organic electrolyte battery according to an embodiment.

2 (a) and 2 (b) are schematic views showing, in the order of steps, a state in which a valve body peripheral portion is caulked and fixed to a dish-shaped sealing plate in a sealing body provided and mounted in an organic electrolyte battery according to an embodiment. Sectional drawing to show.

FIG. 3 is a cross-sectional view schematically showing another state in which the valve body peripheral portion is caulked and fixed to the dish-shaped sealing plate in the sealing body provided and mounted in the organic electrolyte battery according to the example.

FIG. 4 is a characteristic diagram in an overdischarge test of an organic electrolyte battery according to an example.

FIG. 5 is a vertical cross-sectional view showing a configuration example of a main part of a conventional organic electrolyte battery.

FIG. 6 is a vertical cross-sectional view showing another example of the configuration of a main part of a conventional organic electrolyte battery.

FIG. 7 is a cross-sectional view showing the structure of a PTC element plate for blocking current, which is included in the organic electrolyte battery.

8 is a sectional view schematically showing a deformed state of a PTC element plate in the organic electrolyte battery shown in FIG.

9 is a characteristic diagram of an organic electrolyte battery illustrated in FIG. 5 in an overdischarge test.

[Explanation of symbols]

 1,6 …… Outer can 2,7 …… Battery power generating element 3,8 …… Sealing body 4,9 …… Insulating packing 3a, 8a …… Valve 3b, 8b …… Valve 3c, 3c ′, 3c ″ …… Insulating spacers 3d, 3d ′, 8c,… Plate-shaped sealing plates 3e, 8d …… PTC element plates 3f, 8e …… Caps 3f ′, 8e ′ …… Cutting edges 3f ″, 8e ″ …… Gas vent hole 5,10 ...... Lead piece 11 …… Mold 12 …… Stainless steel piece

Claims (1)

[Claims] 1. An outer can, which also functions as a negative electrode terminal, in which an organic electrolyte-based battery power generating element is housed, and a positive electrode terminal which hermetically seals the opening of the outer can by caulking with an insulating packing material. A double-sided sealing body, a lead piece for electrically connecting the sealing body and the positive electrode side of the battery power generating element, and a PTC forming a part of a conductive circuit between the positive electrode terminal and the lead piece.
In the organic electrolyte battery having an element, the sealing body corresponds to the valve body and a flat peripheral plate-shaped sealing plate in which a peripheral portion of the valve body is attached to the valve mouth provided in the central portion by caulking and fixing. The annular PTC element plate stacked on the flat peripheral surface of the dish-shaped sealing plate and the area corresponding to the valve element protrude, and the cutting edge and the vent hole are provided in this protruding portion. An organic electrolyte battery comprising a plate-shaped sealing plate and a cap having a peripheral flat portion laminated on the peripheral flat surface of the plate-shaped sealing plate via the PTC element.