KR101306809B1 - Cylinderical nonaqueous electrolyte primary battery - Google Patents

Abstract

The present invention provides a cylindrical nonaqueous electrolyte primary battery having excellent long-term reliability.

A cylindrical nonaqueous electrolyte primary battery having a positive electrode, a negative electrode containing lithium or a lithium alloy, a separator, and a nonaqueous electrolyte in a space formed by a cylindrical outer can and a battery cover for sealing an opening of the outer can. A cylindrical non-aqueous electrolyte primary battery, characterized by having an insulating film or a film that can occlude lithium ions in a portion of the metal exposed portion of the inner surface of the lid having a potential of the negative electrode.

Description

Cylindrical nonaqueous electrolyte primary battery {CYLINDERICAL NONAQUEOUS ELECTROLYTE PRIMARY BATTERY}

BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal side view which shows an example of the cylindrical nonaqueous electrolyte primary battery of this invention.

[Description of Drawings]

1: cylindrical non-aqueous electrolyte primary battery 2: outer can

3: wound electrode structure 4: strip-shaped anode

5: strip-shaped cathode 6: separator

7: battery cover 8: cover plate

9: Insulation packing 10: Terminal body

17: Insulation film or the film which can occlude lithium ion

The present invention relates to a cylindrical nonaqueous electrolyte primary battery, and more particularly, to a cylindrical nonaqueous electrolyte primary battery having excellent long-term reliability. In addition, the present invention also includes a tubular shape (eg, an angular tubular shape) other than the cylindrical one, but the description will be mainly focused on the cylindrical shape which is a typical form of the battery of the present invention.

In general, a cylindrical non-aqueous electrolyte primary battery has an electrode body formed by stacking a negative electrode and a positive electrode including lithium as an active material between separators, or winding it again, and inserting an electrode body into an outer can, and a battery cover is used to It is comprised by sealing an opening part (for example, patent document 1).

Since this type of battery uses lithium or the like for the negative electrode active material, it has a higher energy density than the battery having, for example, an alkaline electrolyte solution, and can be applied to long-term use, and thus is used in various applications.

One of the applications of the cylindrical nonaqueous electrolyte primary battery is the use of a power supply for memory backup. In a device having a memory backup function, a cylindrical non-aqueous electrolyte primary battery is applied as a power source for memory backup only, not a main driving power source.

[Patent Document 1]

Japanese Patent Application Laid-Open No. 3-122970

By the way, when a cylindrical nonaqueous electrolyte primary battery is used as a memory backup power supply in a device having the memory backup function as described above, the cylindrical nonaqueous electrolyte primary battery may be charged by a leakage current from the driving power supply of the device. . And when it used for a long time as a memory backup power supply, it became clear by the present inventors that the said voltage may generate | occur | produce the voltage of a cylindrical non-aqueous electrolyte primary battery by the said charge.

This invention is made | formed in view of the said situation, and the objective is to provide the cylindrical nonaqueous electrolyte primary battery excellent in long-term reliability.

The cylindrical non-aqueous electrolyte primary battery of the present invention obtained by achieving the above object is formed of a positive electrode, a negative electrode containing lithium or a lithium alloy, a separator, and a non-aqueous electrolyte with a cylindrical outer can and a battery cover for sealing the opening of the outer can. It has a space and has a film which can occlude an insulation film or lithium ion in the part which has the potential of a negative electrode among the metal exposure parts of the inner surface of said battery cover.

The inventors of the present invention have studied the mechanism of voltage drop in a cylindrical nonaqueous electrolyte primary battery, for example, when the battery is used for a long time in memory backup applications. As a result of charging the battery, the potential of the negative electrode in the metal exposed portion of the inner surface of the battery cover is mainly determined. Lithium precipitated in the branch portion, and it was found that a short circuit occurred by contacting the portion having the potential of the positive electrode of the battery cover, causing a voltage drop in the battery.

Therefore, in the present invention, an insulating film or a film that can occlude lithium ions is provided in a portion where lithium which is the cause of the short circuit can be deposited, that is, a portion of the metal exposed portion of the inner surface of the battery cover having the potential of the negative electrode. By providing the insulating film, conductivity was lost in the portion. Moreover, by providing the film which can occlude the said lithium ion, the lithium ion which becomes a source of lithium precipitation is occluded in the said part. As a result, even when the battery is charged, precipitation of the lithium ions dissolved in the nonaqueous electrolyte can be prevented, thereby suppressing occurrence of voltage drop due to the short circuit and improving the long-term reliability of the battery. It was made.

The longitudinal side view which shows one Embodiment of the battery of this invention in FIG. The cylindrical nonaqueous electrolyte battery 1 shown in FIG. 1 includes a bottomed cylindrical outer can 2 having an upper opening, a strip-shaped positive electrode 4 and a strip-shaped negative electrode 5 loaded in the outer can 2. Seals for sealing the electrode wound body 3 formed by winding the separator 6 therebetween, the nonaqueous electrolyte (hereinafter, simply referred to as "electrolyte") and the upper opening of the outer can 2. Has a structure. In other words, the nonaqueous electrolyte primary battery 1 of FIG. 1 has a band-shaped positive electrode 4 and a band-shaped negative electrode in a space surrounded by a sealing structure for sealing the outer can 2 and the upper opening of the outer can 2. It has a power generation element, such as the electrode body 3 of the winding structure formed by winding 5) through the separator 6, and electrolyte solution.

In addition, the strip-shaped positive electrode 4 of the battery of FIG. 1 has a structure in which two positive electrode mixture layers 20 and 21 containing a positive electrode active material, a conductive aid, a binder, and the like are provided on both sides of the positive electrode current collector 22. Have. Moreover, the strip | belt-shaped negative electrode 5 has the structure which the metal lithium foil 23 adhered to one surface of the negative electrode collector 24. As shown in FIG. The outer can 2 is made of iron, stainless steel, or the like.

The sealing structure is constituted by the battery cover 7 fixed to the inner circumferential edge of the upper opening of the outer can 2. The battery cover 7 includes a cover plate 8 made of metal (iron, stainless steel, etc.) and an insulating packing 9 made of polypropylene in a hole formed in the center of the cover plate 8. It has a terminal body 10 made of attached metal (iron, stainless steel, etc.). The insulating plate 11 is disposed below the cover plate 8 of the battery cover 7. The insulating plate 11 is formed in the shape of a round plate which opens upwards in which the annular side wall 13 is placed on the circumferential edge of the disc-shaped base portion 12, and in the center of the base portion 12 is a gas cylinder. (14) is open. The cover plate 8 of the battery cover 7 is fixed to the inner circumferential edge of the upper opening of the outer can 2 by the laser welding, or is fixed with a roughly clamped seal in a state of being received at the upper end of the side wall 13. have. As a countermeasure when the battery breakdown voltage has risen sharply, a thin portion (vent) can be provided on the can bottom 2a of the cover plate 8 or the outer can 2. The lower surface of the positive electrode 4 and the terminal body 10 is connected to the positive electrode lead body 15. In addition, the negative electrode lead body 16 provided on the negative electrode 5 is welded to the upper inner surface of the outer can 2.

That is, in the battery shown in FIG. 1, the outer can 2 in which the negative electrode lead body 16 provided on the negative electrode 5 is welded has a potential of the negative electrode and is welded to the outer can 2 ( 7) The cover plate 8 also has a potential of the negative electrode among the metal exposed parts on the inner surface. On the other hand, the terminal body 10 connected to the positive electrode lead body 15 provided in the positive electrode 4 among the metal exposed portions on the inner surface of the battery cover 7 has a potential of the positive electrode.

When the cylindrical non-aqueous electrolyte primary battery is used for a long period of time and is charged therebetween, the surface of the cover plate 8 in which lithium ions dissolved in the electrolyte have a potential of the negative electrode in the metal exposed portion of the battery cover 7 inner surface. Precipitates as lithium, and when lithium comes into contact with the surface of the terminal body 10 having the potential of the positive electrode among the metal exposed portions on the inner surface of the battery cover, an unshorted circuit occurs, causing a voltage drop of the battery. In the battery shown in Fig. 1, an insulation film or a film 17 capable of absorbing lithium ions is provided on the surface of the cover plate 8 having the potential of the negative electrode among the metal exposed portions on the inner surface of the battery cover 7. By preventing the precipitation of lithium on the surface of (8), occurrence of voltage drop due to the above short circuit is suppressed.

In addition, although the battery of the form which has the electrode body 3 of a wound structure was shown in FIG. 1, in the battery of this invention, an electrode body may have a laminated structure which laminated | stacked the positive electrode and the negative electrode through the separator. Moreover, even if it is a battery which has an electrode body of a wound structure, the structure of a positive electrode or a negative electrode is not limited to what is shown in FIG. 1, For example, the positive electrode may be what provided the positive electrode mixture layer only in one surface of the positive electrode collector, The silver negative electrode collector may have a negative electrode layer composed of a metal lithium foil, a lithium alloy foil, or the like on both sides of the current collector.

In addition, in the battery of FIG. 1, the cover plate 8 has the potential of the negative electrode and the terminal body 10 has the potential of the positive electrode among the metal exposed portions of the inner surface of the battery cover 7. Battery may be in the form where the cover plate 8 has the potential of the positive electrode and the terminal body 10 has the potential of the negative electrode. In such a case, the insulating film or the lithium ion may be formed on the inner surface of the terminal body 10. What is necessary is just to provide the film | membrane which can occlude | disconnect.

Although not shown in Fig. 1, in the case of a battery in which the metal exposed portion of the inner surface of the outer can has the potential of the negative electrode, it is also preferable to provide an insulating film or a film capable of absorbing lithium ions in the metal exposed portion of the outer can. In the case of the battery of this type, lithium may be deposited on the metal exposed portion of the inner surface of the outer can by being charged during prolonged use, and the insulating film or lithium ion may be stored in the metal exposed portion of the inner surface of the outer can. Precipitation of such lithium can be suppressed by providing a coating, whereby the occurrence of the short circuit can be prevented more highly.

In the battery of the present invention, the insulating film is not particularly limited as long as the insulating film is made of a material which can lose the conductivity of the portion on which the insulating film is provided and which is not dissolved in the electrolyte and does not adversely affect the battery characteristics. Specifically, a film formed of polyvinylidene fluoride (PVDF), a rubber material (butyl rubber, polyisobutyrene rubber or a mixture thereof, or the like), water glass (sodium silicate aqueous solution), or the like is preferable.

In the battery of the present invention, the film that can occlude lithium ions is not particularly limited as long as it is made of a material that can occlude lithium ions and is not dissolved in the electrolyte and does not adversely affect battery characteristics. Specifically WO ₂ , MoO ₂ . Fe ₂ O ₃ , TiS ₂ Inorganic compounds such as these; Carbonaceous materials such as graphite and carbonaceous materials obtained by firing organic materials; Materials, such as these, are mentioned. These materials can occlude lithium ions in the crystal structure or the amorphous structure. Moreover, the carbonaceous material obtained by baking graphite and an organic substance is especially preferable at the point which is more easily available among the material which can occlude lithium ion of the said example.

The film that can occlude lithium ions may be formed of only that material when using a material having a film forming ability. However, when a material having no film forming ability is used, a coating is preferably used in combination. As the binder, for example, polyvinylidene fluoride (PVDF), rubber-based materials (butyl rubber, polyisobutyrene rubber or mixture thereof), water glass (sodium silicate aqueous solution), imide-based materials and the like can be used. When using a binder together and forming the film which can occlude lithium ion, it is preferable to make the ratio of the material which can occlude lithium ion in a film into 5 to 70 mass%, for example.

In manufacturing a battery cover or an outer can having an insulating film or a film that can occlude lithium ions, processing the battery cover or an outer can into the shape of the battery cover or the outer can with respect to a material (metal plate such as steel sheet, etc.) constituting the battery cover or the outer can. It is preferable to form an insulating film beforehand. This is because the film formation becomes easier by adopting such a formation method. Specifically, a battery cover or an outer can is manufactured so that the forming surface of the insulating film or the lithium ion-containing film is inside the battery using a metal plate such as a steel plate having an insulating film or a lithium-ion-containing film formed on one surface thereof. Do it.

There is no particular limitation on the method of forming an insulating film or a lithium ion-containing film on a battery cover, an outer can, or a metal plate made of these materials. For example, the insulating film or lithium ion may be occluded with PVDF or the rubber-based material. In the case of forming a film, a method in which these organic solvent solutions are applied to an insulating film forming scheduled portion, dried to remove a solvent, and water glass is used to form an insulating film or a film that can occlude lithium ions. May be applied to an insulating film or a film forming scheduled portion capable of storing lithium ions, and dried to remove water. Moreover, as an organic solvent used for the organic solvent solution of PVDF, N-methyl- 2-pyrrolidone (NMP) etc. are suitable, for example, As an organic solvent used for the organic solvent solution of the said rubber type material, For example, toluene and the like are suitable. In addition, when using a carbonaceous material as a material which can occlude lithium ion, you may form a film using the well-known carbon paste marketed as an electrically conductive paste.

The thickness of the insulating film is not particularly limited as long as the deposition of lithium dendrites can be suppressed, but is preferably 3 to 100 µm. If the insulating film is too thin, the suppression effect of lithium dendrite deposition may be reduced. If the insulating film is too thick, the volume of the battery occupied by the insulating film is increased, and the volume to accommodate other components (battery or electrolyte, etc.) may be reduced. In addition, it becomes difficult to form an insulating film.

There is no restriction | limiting in particular about the thickness of the film which can occlude lithium ion, if lithium can be suppressed, but it is preferable that it is 5-100 micrometers, for example. If the film that can occlude lithium ions is too thin, the inhibitory effect of lithium deposition may be reduced. If too thick, the occupied volume of the battery due to the film that can occlude lithium ions increases and accommodates other components (such as electrodes and electrolytes). The volume which can be made may become small, and it becomes difficult to form the film which can occlude lithium ion.

In the cylindrical non-aqueous electrolyte primary battery of the present invention, there is no particular limitation on the components except for the insulating film or the film that can occlude lithium ions, and various conventionally known components can be employed.

Examples of the positive electrode include a structure in which a positive electrode mixture layer composed of a positive electrode mixture comprising a positive electrode active material, a conductive aid, a binder, and the like is formed on one or both surfaces of a positive electrode current collector.

Examples of the positive electrode active material include manganese dioxide, carbon fluoride, lithium cobalt composite oxide, spinel type lithium manganese composite oxide, and the like. Moreover, as a conductive support agent, graphite, carbon black, acetylene black, Ketjen black, etc. are mentioned, for example, You may mix and use 2 or more types other than this using individually by 1 type. As the binder, PVDF, rubber-based materials (such as those exemplified as rubber-based materials for forming the insulating film) and the like can be used. In the case of PVDF, the dispersion type may be good or the powder type may be good, but the dispersion type is particularly suitable.

As the positive electrode mixture layer, for example, a positive electrode active material is mixed with a conductive aid and a binder, and a positive electrode mixture (slurry) formed by adding water or the like, if necessary, is preliminarily formed by rolling using a roll or the like. What dried and pulverized what was shape | molded in layer form (sheet form) by roll rolling etc. can be used. As thickness of a positive mix layer, it is preferable that it is 0.5-1.0 mm, for example.

Examples of the current collector used for the positive electrode include those made of stainless steel such as SUS316, SUS430, and SUS444, and examples thereof include plain weave gold mesh, expanded metal, lath mesh, punching metal, foil (plate), and the like. Can be illustrated. As thickness of an electrical power collector, it is preferable that it is 0.1-0.4 mm, for example.

In addition, it is preferable to apply a paste-like conductive material to the surface of the positive electrode current collector. Even when a net-like thing having a three-dimensional structure is used as the positive electrode current collector, remarkable improvement in current collector effect is recognized by application of a conductive material as in the case of using a material consisting essentially of a flat plate such as metal foil or punching metal. This is presumably due to the fact that not only the path where the metal part of the mesh current collector is in direct contact with the positive electrode mixture layer, but also the path through the conductive material filled in the mesh is effectively used.

As a conductive material, silver paste, carbon paste, etc. can be used, for example. In particular, since the carbon paste has a lower material cost than the silver paste and a substantially equivalent contact effect with the silver paste, the carbon paste is suitable for reducing the manufacturing cost of the nonaqueous electrolyte battery. As a binder of a electrically conductive material, it is preferable to use heat resistant materials, such as water glass and an imide binder. This is because the drying treatment is performed at a high temperature exceeding 200 ° C. when removing the moisture in the positive electrode mixture layer.

As a negative electrode, the thing comprised by the negative electrode layer which consists of lithium or lithium alloy (lithium-aluminum alloy etc.) which are negative electrode active materials, and the metal foil which is a negative electrode electrical power collector is mentioned, for example. As the negative electrode layer, for example, lithium (metal lithium) foil, lithium alloy foil, or the like can be used. As thickness of the lithium foil and lithium alloy foil for using as a negative electrode layer, it is preferable that it is 0.15-0.4 mm, for example.

Copper, nickel, iron, stainless, etc. are mentioned as a raw material of a negative electrode electrical power collector. Since the internal volume of the outer can can be reduced by the thickness of the negative electrode current collector, it is preferable that the thickness of the negative electrode current collector is as small as possible, specifically, it is recommended to be 0.1 mm or less, for example. In other words, if the negative electrode current collector is too thick, the amount surrounding the lithium foil or the lithium alloy foil, which is the negative electrode active material, may be reduced, leading to a decrease in battery capacity. In addition, if the negative electrode current collector is too thin, it is easily broken, so the thickness of the negative electrode current collector is preferably 0.005 mm or more. In addition, it is preferable that the width of the negative electrode current collector is equal to or wider than that of the lithium foil or the lithium alloy foil, and the area is 100 to 130% of the area of the lithium foil or the lithium alloy foil disposed on one side. desirable. By making the area of the negative electrode current collector as described above, the width of the negative electrode current collector is equal to or wider than that of the lithium foil or the lithium alloy foil, and the length becomes longer, so that the lithium foil or the lithium alloy foil is formed around the negative electrode current collector. It is possible to prevent the electrical connection from being cut off by breaking.

As the separator, a separator made of a microporous film and a separator made of a nonwoven fabric which are conventionally used in a known nonaqueous electrolyte primary battery can be used.

As resin which comprises the microporous film used as a separator, For example, Polyolefin, such as polyethylene (PE) and polypropylene (PP); Polyesters such as polyethylene terephthalate (PET) and polybutyrene terephthalate (PBT); Polyphenylene sulfide (PPS); And the like. As a commercial item of such a microporous film, "Hypoa" (brand name) by Asahi Kasei Co., Ltd. (brand name), "Setira" (trade name) by Tonen Kagaku Co., Ltd. are mentioned, for example.

Moreover, as a nonwoven fabric used as a separator, For example, Polyolefin, such as polyethylene (PE) and polypropylene (PP); Polyesters such as polyethylene terephthalate (PET) and polybutyrene terephthalate (PBT); Polyphenylene sulfide (PPS); It is possible to use, for example, materials manufactured by various known manufacturing methods.

Moreover, you may use the separator of the structure which laminated | stacked the said microporous film and the said nonwoven fabric.

It is preferable that the thickness of a separator is 15-50 micrometers, for example.

In constructing a battery, for example, a positive electrode and a negative electrode are laminated with a separator interposed therebetween to form a laminated electrode body, or a band-shaped positive electrode and a band-shaped negative electrode are wound in a state where a separator is interposed and used as an electrode body of a wound structure. It is desirable to.

Examples of the electrolyte include those prepared by dissolving LiPF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , or the like as an electrolyte in a non-aqueous solvent such as an organic solvent. As this solvent, what mixed cyclic ester, such as ethylene carbonate and a propylene carbonate, with chain ester, such as chain ether, such as dimethoxyethane, and dimethyl carbonate, can be illustrated. As concentration of electrolyte in electrolyte solution, 0.3-1.5 mol / l is preferable.

The cylindrical non-aqueous electrolyte primary battery of the present invention is used for a long time, and even when used for applications that are charged therebetween, occurrence of voltage drop is suppressed, and excellent long-term reliability. Therefore, the battery of the present invention can be suitably used for various applications such as a power supply for memory backup by utilizing such characteristics.

[Example]

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on an Example. However, the following Examples do not limit the present invention, and all modifications are made within the technical scope of the present invention without departing from the spirit and scope of the present invention. In this embodiment, a cylindrical nonaqueous electrolyte primary battery having an outer diameter of 17 mm and a height of 45 mm will be described as an example of the nonaqueous electrolyte primary battery. In addition, "%" used by a present Example is a mass reference | standard (mass%) unless there is particular understanding.

Example 1

The nonaqueous electrolyte primary battery of Example 1 will be described in the order of [production of positive electrode], [production of negative electrode], [production of electrode winding body], [cell assembly], and [post-processing (preliminary discharge, aging)]. .

[Production of anode]

First, a positive electrode mixture (solid content: water = 100: 30 in mass ratio) was prepared in the following procedures. Carbon black: 3% and manganese dioxide (manufactured by Tosoh Corporation): 92% were mixed by dryness using a planetary mixer for 5 minutes, and water was added so as to be 20% (mass ratio) of solids and mixed for 5 minutes. Prepare PVDF dispersion ("D-1" manufactured by Daikin Industries Co., Ltd.) in an amount corresponding to 5% of the solid content of the solid mixture of the positive electrode mixture, dilute it with the remaining water, add it to the mixture, and mix for 5 minutes to mix the positive electrode mixture. Got.

The cathode mixture was adjusted to a roll temperature of 125 ± 5 ° C. using two rolls having a diameter of 250 mm, roll pressure under conditions of a press pressure of 7 tons / cm, a roll interval of 0.4 mm, and a rotational speed of 10 rpm. To form a sheet. The positive electrode mixture (preliminary sheet) that passed through the roll was rolled at 105 ± 5 ° C until the remaining water became 2% or less. Next, the preliminary sheet after drying was pulverized using a grinder. At this time, the preliminary sheet was pulverized until it became at least twice the original apparent volume. Most of the particle diameter after grinding | pulverization was 1 mm or less, and PVDF added as a binder was also cut | disconnected to the fiber shape of length 1 mm or less. The material after grinding | pulverization was made into the sheet | seat by the roll again. The space | interval of rolls was adjusted to 0.6 +/- 0.05 mm, it sheeted on the conditions of roll temperature: 125 +/- 10 degreeC, press pressure: 7 ton / cm, and rotational speed: 10 rpm, and obtained the positive electrode mixture sheet for making a positive electrode mixture layer. . The obtained positive electrode mixture sheet had a thickness of 1.0 mm and corresponds to 5.9% of the outer can inner diameter. Moreover, the density of the positive mix sheet was 2.5 g / cm <3>, and the porosity calculated by the said method was 42%. The positive electrode mixture sheet was cut to obtain an inner positive electrode mixture sheet having a width of 37 mm and a length of 51 mm, and an outer positive electrode mixture sheet having a width of 37 mm and a length of 62 mm.

As the positive electrode current collector, an expanded metal made of stainless steel (SUS316) was used. The expanded metal was cut into a width of 34 mm and a length of 56 mm, and a stainless steel ribbon having a thickness of 0.1 mm and a width of 3 mm was provided by resistance welding in a central portion in the longitudinal direction as an anode lead body. Carbon paste (manufactured by Nippon Kokuen Co., Ltd.) was applied to the expanded metal so as not to deform the mesh, and dried at a temperature of 105 ± 5 ° C. to obtain a positive electrode current collector. In addition, the coating amount of the carbon paste was 5 mg / cm 2 in the coating amount after drying.

Next, in the state where the positive electrode current collector was interposed between the inner circumferential positive electrode mixture sheet and the outer circumferential positive electrode mixture sheet, only one end portion in the longitudinal direction was fixed to integrate the three characters. Specifically, the inner circumferential positive electrode mixture sheet and the outer circumferential positive electrode mixture sheet are aligned with one end in the longitudinal direction, and the end of the positive electrode current collector is set so as not to protrude from one end where the two positive electrode mixture sheets are aligned. In this state, a three-millimeter portion was integrated by pressing a portion of 5 mm from one end where the two positive electrode mixture sheets were aligned. Thereafter, the two positive electrode mixture sheets and the positive electrode current collector were integrally hot-air dried at 250 ± 10 ° C. for 6 hours to obtain a band-shaped positive electrode having a width of 37 mm.

[Production of negative electrode]

The cathode is a metal lithium foil having a width of 39 mm, a length of 170 mm, a thickness of 10 μm, and a thickness of 37 mm, a length of 87 mm, a thickness of 0.30 mm, and a width of 37. A metallic lithium foil of mm, length: 50 mm, and thickness: 0.30 mm was disposed and configured. First, a negative electrode lead body made of nickel having a width of 3 mm, a length of 20 mm, and a thickness of 0.1 mm was pressed on a metal lithium foil having a length of 50 mm. Then, it arrange | positioned on the said copper foil in the state which separated said two metal lithium foils, and produced the strip-shaped negative electrode.

[Production of wound electrode body]

As a separator, a microporous polyethylene film ("Hypoa" (trade name) manufactured by Asahi Kasei Co., Ltd.) having a width of 44 mm, a length of 170 mm, and a thickness of 25 μm was prepared.

An adhesive tape was stuck on the copper foil of a sheet-shaped negative electrode, and the separator was stuck to this adhesive tape by heat welding. Next, the heat-welded portion of the separator was inserted into a winding core having a diameter of 3.5 mm divided into two, and wound around one round. Next, after winding the negative electrode with the separator one round, the fixed side of the strip-shaped positive electrode was mounted on the wound core side and wound. After the winding was finished, copper foil became the type covering the outermost circumference. The electrode body of the wound structure was obtained by the above.

[Battery Assembly]

An assembling process of the nonaqueous electrolyte battery will be described with reference to FIG. 1. An insulating plate made of polypropylene having a thickness of 0.2 mm was inserted into the inner bottom portion 2a of the bottomed cylindrical outer can 2 made of nickel-plated iron cans, and the electrode body 3 was placed on the anode lead body 15 thereon. ) Is inserted in an upward facing position. After resistance welding of the negative electrode lead body 16 of the electrode body 3 to the inner surface of the outer can 2, the positive electrode lead body 15 inserts the insulating plate 11, and then the terminal plate 10 of the battery cover 7. Resistance welding was performed on the lower surface. At this point, insulation resistance was measured, and it was confirmed that there was no short circuit.

As the battery cover 7, a steel plate provided with a PVDF insulating film having a thickness of 10 µm was used, which was formed using a cover plate 8 processed such that the film forming surface was inside the battery. This insulating film was formed by applying a solution (concentration 12%) obtained by dissolving "KF Polymer # 1120 (trade name) made by Kureha Chemical Co., Ltd. in NMP on one side of a steel sheet and drying.

The electrolyte was prepared with a non-aqueous solution in which LiClO ₄ was dissolved at a concentration of 0.5 mol / l in a mixed solvent of propylene carbonate and dimethoxyethane (1: 2 by volume), and 3.5 ml of the solution was injected into the outer can (2). It was. Injection was divided into three times and the whole quantity was injected, decompressing in a final process. After the injection of the electrolyte, the battery cover 7 is fitted into the upper opening of the outer can 2, and the inner periphery of the open end of the outer can 2 and the cover plate 8 of the battery cover 7 are formed by laser welding. The outer periphery was welded to seal the opening of the outer can 2.

[Post-processing (Preliminary Discharge, Aging)]

The sealed battery was preliminarily discharged for 30 seconds at a resistance of 1 mA, and stored at 70 ° C. for 6 hours, followed by secondary preliminary discharge for 1 minute at a constant resistance of 1 mA. The battery after preliminary discharge was aged at room temperature for 7 days, and the open circuit voltage was measured to confirm that a stable voltage was obtained. A nonaqueous electrolyte primary battery having an outer diameter of 17.0 mm and a total height of 45.0 mm was obtained. The ratio of the negative electrode capacity and the positive electrode capacity of this nonaqueous electrolyte primary battery was 1.00.

Example 2

A nonaqueous electrolyte solution was prepared in the same manner as in Example 1, except that the battery cover 7 was formed of a steel plate provided with an insulating coating having a thickness of 10 μm, using a cover plate 8 processed so that the film forming surface was inside the battery. Primary batteries were fabricated. This insulating film was formed by applying a solution (concentration 10%) obtained by Nitto Shinko Co., Ltd. "Elept Coat LSS-810 (trade name)" to toluene and dissolving it on one side of the steel sheet and drying it.

Example 3

As the battery cover 7, a steel plate provided with a film containing a carbonaceous material having a thickness of 20 μm (a film capable of absorbing lithium ions) was used using a cover plate 8 in which the film-forming surface was processed to be inside the battery. A nonaqueous electrolyte primary battery was produced in the same manner as in Example 1 except for the above. This film was formed by applying "Bani Height IV-174 (trade name)" manufactured by Nihon Kokuen Co., Ltd. to one side of the steel sheet and drying.

Example 4

The cover plate 8 which processed the steel plate which has the film (film | membrane which can occlude lithium ion) formed with the thickness of 20 micrometers carbonaceous material formed by the following method as the battery cover 7 so that a film forming surface may be inside a battery. A non-aqueous electrolyte primary battery was produced in the same manner as in Example 1 except that the same was used. This film was formed by applying to a surface of a steel sheet a liquid composition containing NMP prepared as graphite ("KS15" manufactured by Lonzer Corporation) and PVDF at 97: 3 (mass ratio) as a solvent, followed by drying.

Comparative Example 1

A nonaqueous electrolyte primary battery was produced in the same manner as in Example 1 except that the battery cover 7 was not provided with an insulating film or a film capable of storing lithium ions on the inner surface of the cover plate 8.

The following long-term reliability test was done about the battery of Examples 1-4 and Comparative Example 1. The open-circuit voltage was measured for each battery whose stable voltage was obtained through the above preliminary discharge and aging (this is referred to as initial voltage). After storing these batteries for 50 days at 60 DEG C while charging at a current of 10 mA, the open-circuit voltage was measured again, and it was determined that the short-circuit was a short-circuit soft short product that the voltage was lowered by 20 mV or more from the initial voltage. It was. The number of samples of each battery was made into 20 pieces, and the number of the soft short goods was investigated among them. That is, the smaller the number of soft short products, the better the long-term reliability. The results are shown in Table 1.

Soft short
(Number of occurrence / total number of samples) Example 1 0/20 Example 2 0/20 Example 3 0/20 Example 4 0/20 Comparative Example 1 9/20

As can be seen from Table 1, in the nonaqueous electrolyte primary batteries of Examples 1 to 4, even if stored for a long time at a high temperature while charging, there was no soft short occurred and excellent long-term reliability. Even if these non-aqueous electrolyte primary batteries were decomposed after a long-term reliability test, no deposition of lithium was observed on the inner surface of the cover plate 8.

On the other hand, when the battery of Comparative Example 1, which was determined to be a soft short product by the long-term reliability test, was disassembled after the test, lithium was deposited on the inner surface of the cover plate 8, which was not brought into contact with the terminal body 10. A short circuit can be thought of as occurring.

ADVANTAGE OF THE INVENTION According to this invention, the cylindrical nonaqueous electrolyte primary battery excellent in long-term reliability can be provided.

Claims (9)

A cylindrical nonaqueous electrolyte primary battery having a positive electrode, a negative electrode containing lithium or a lithium alloy, a separator, and a nonaqueous electrolyte in a space formed by a cylindrical outer can and a battery cover for sealing an opening of the outer can. At least a portion of the metal exposed portion of the inner surface of the battery cover has an insulating film having a potential of the negative electrode, The battery cover has a cover plate, a terminal body, and an insulating packing disposed between the cover plate and the terminal body, A cylindrical nonaqueous electrolyte primary battery, wherein one of the cover plate and the terminal body has a potential of a negative electrode and the other has a potential of a positive electrode. delete The method of claim 1, A cylindrical non-aqueous electrolyte primary cell, wherein the outer can has a potential of a negative electrode and an insulating film on an inner surface of the outer can. The method of claim 1, A cylindrical non-aqueous electrolyte primary battery, wherein the insulating film is formed of polyvinylidene fluoride, water glass, or rubber-based material. 5. The method of claim 4, A cylindrical nonaqueous electrolyte primary battery, wherein the rubber material is butyl rubber, polyisobutyrene rubber, or a mixture thereof. A cylindrical nonaqueous electrolyte primary battery having a positive electrode, a negative electrode containing lithium or a lithium alloy, a separator, and a nonaqueous electrolyte in a space formed by a cylindrical outer can and a battery cover for sealing an opening of the outer can. At least a portion of the metal exposed portion of the inner surface of the battery cover having a potential of the negative electrode has a film capable of storing lithium ions, The battery cover has a cover plate, a terminal body, and an insulating packing disposed between the cover plate and the terminal body, A cylindrical nonaqueous electrolyte primary battery, wherein one of the cover plate and the terminal body has a potential of a negative electrode and the other has a potential of a positive electrode. delete The method according to claim 6, A cylindrical non-aqueous electrolyte primary cell, wherein the outer can has a potential of a negative electrode and a film capable of storing lithium ions on an inner surface of the outer can. The method according to claim 6, A cylindrical nonaqueous electrolyte primary battery, wherein the film capable of occluding lithium ions is a film containing an inorganic compound or a carbonaceous material capable of occluding lithium ions.

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