JP2000012044A - Nonaqueous electrolytic solution primary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery which is superior in preservation characteristics by using, as a metallic current collector, foil or film made of aluminum alloy, and using as an electrolyte, a nonaqueous electrolytic solution prepared by dissolving at least one kind selected from among those expressed by LiN(CxF2x+1 SO2)(CyF2y+1SO2) (where 1<=x<=4 and 1<=y<=4). SOLUTION: Electrolytic manganese dioxide, a carbon powder as a conductive material, and a fluororesin powder as a binder are mixed together at a weight ratio of 90:5:5, a carboxy-methyl water solution is added thereto and kneaded, a paste-like positive-electrode mix so obtained is applied to both surfaces of an aluminum foil (20 μm thickness) as a current collector, which is dried and then molded into a sheet. This molded sheet body is heat-treated again at 250 deg.C to 300 deg.C, and deposited water is removed, and is set as a positive electrode plate. For a nonaqueous electrolyte solution, a mixed solution of propylene carbonate and 1,2-dimenthoxy-ethane, and a solution of LiN(C2F5SO2)2 as an electrolyte, are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte primary battery, and more particularly to a non-aqueous electrolyte primary battery in which aluminum is used as a positive electrode metal current collector and an electrolyte added to the non-aqueous electrolyte is improved. Things.

[0002]

2. Description of the Related Art A negative electrode using lithium or a lithium alloy as an active material and a non-aqueous electrolyte primary battery using manganese dioxide as a positive electrode active material have a high energy density and can be used in a wide temperature range. Having.
For this reason, in electronic devices such as cameras and portable devices, they are used not only for backup of memories but also as power sources for driving the devices. Batteries used for these applications have been required to be downsized as the electronic devices themselves have been downsized. In particular, in a cylindrical non-aqueous electrolyte primary battery using an electrode body adopting a spiral structure in which a belt-like positive / negative plate is wound with a separator interposed therebetween, the discharge caused by the decrease in the area of the electrode plate accompanying the miniaturization of the battery. It is necessary to reduce the thickness of the electrode plates in order to prevent the deterioration of the discharge characteristics caused by the voltage drop or the like.

[0003]

Heretofore, a mesh-shaped core material obtained by cutting a stainless steel and enlarging the cut, a so-called lath, has been used for the positive electrode current collector of the nonaqueous electrolyte primary battery. . However, when the thickness of each mesh of the lath is reduced in the positive electrode current collector using the lath, the strength of the core material itself is insufficient, and the function as a current collector holding the active material cannot be achieved. Further, a method of thinning stainless steel to obtain a foil or film-like current collector is also conceivable, but it is economically expensive, and it is practically difficult to produce a thin electrode plate using the obtained current collector. is there.

[0004] Therefore, a method of applying aluminum generally used in chargeable / dischargeable nonaqueous electrolyte secondary batteries to the nonaqueous electrolyte primary batteries can be considered. Since aluminum is inexpensive and rich in malleability, the thickness of the positive electrode current collector can be reduced.

[0005] However, when aluminum is applied to the positive electrode current collector, LiCF ₃ S, which is an electrolyte of a non-aqueous electrolyte generally used in a non-aqueous electrolyte primary battery, is used.
O ₃ cannot be used. For this reason, Li
The non-aqueous electrolyte using CF ₃ SO ₃ as an electrolyte dissolves the Al ₂ O ₃ film formed on the surface of the current collector using aluminum, and also dissolves the aluminum inside the coating. It loses its function.

On the other hand, in a non-aqueous electrolyte secondary battery,
LiPF _{6 in} which the Al ₂ O ₃ coating does not dissolve is dissolved in the non-aqueous electrolyte as an electrolyte. Therefore, when LiPF ₆ is applied to a non-aqueous electrolyte primary battery, PF ₆ ^-which is unstable at normal temperature reacts with a small amount of water present in the battery can to generate hydrofluoric acid. Furthermore, the generated hydrofluoric acid reacts with the negative electrode lithium during storage of the battery, and the storage characteristics are significantly deteriorated due to these reactions.

An object of the present invention is to reduce the size of a battery provided with a spirally structured electrode body, and to provide a nonaqueous electrolyte having excellent storage characteristics, comprising a positive electrode using aluminum as a positive electrode current collector. A primary battery is provided.

[0008]

In order to achieve the above object, the present invention provides a positive electrode having manganese dioxide as a main active material and a metal current collector, a negative electrode having lithium or a lithium alloy as an active material, and In a non-aqueous electrolyte primary battery comprising a non-aqueous electrolyte in which an electrolyte is dissolved in an aqueous solvent, a metal current collector made of aluminum, a general formula LiN (C _X F
_{2X + 1 SO 2) (C} Y F 2Y + 1 SO 2) ( provided that, 1 ≦ X ≦
4, 1 ≦ Y ≦ 4).

When the electrolyte according to the present invention is used, the dissolution of the Al ₂ O ₃ film formed on the surface of the aluminum serving as the positive electrode current collector occurs when the potential of the positive electrode with respect to the negative electrode lithium is 4.0 V or more. Only happens. For this reason,
The non-aqueous electrolyte primary battery of the present invention, in which the potential generated between the positive and negative electrodes is about 3.7 V or less, does not cause the dissolution of the Al ₂ O ₃ coating on the aluminum surface of the positive electrode current collector, The positive electrode current collector is always in a stable state. For this reason, it becomes possible to use aluminum for the positive electrode current collector. Furthermore, since hydrofluoric acid is not generated by the reaction with moisture, the storage characteristics are excellent.

The electrolyte of the non-aqueous electrolyte is LiClO ₄
Also when using, without dissolving the aluminum that is the positive electrode current collector, it is possible to improve the storage characteristics of the battery, but there is a problem in the state at the time of battery over-discharge, the electrolyte according to the present invention Is more preferred.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below for the understanding of the present invention.

According to the first aspect of the present invention, an electrolyte is dissolved in a positive electrode having manganese dioxide as a main active material and a metal current collector, a negative electrode having lithium or a lithium alloy as an active material, and a non-aqueous solvent. A non-aqueous electrolyte primary battery comprising a non-aqueous electrolyte, wherein an aluminum foil or a film is used as a metal current collector, and LiN (C _X F _{2
X + 1 SO 2) (C} Y F 2Y + 1 SO 2) ( provided that, 1 ≦ X ≦ 4,
A non-aqueous electrolyte in which at least one selected from those represented by 1 ≦ Y ≦ 4) is dissolved is used.

The positive electrode applied to the nonaqueous electrolyte primary battery according to the present invention is an active material obtained by mixing an active material such as electrolytic manganese dioxide and chemical manganese dioxide, and a conductive material and a binder with a liquid such as water. The paste is obtained by applying the paste to an aluminum foil or an aluminum film as a current collector and drying the paste.
On the other hand, the negative electrode is exemplified by metal lithium or a lithium aluminum alloy.

The solvent for dissolving the electrolyte in the present invention is:
Although not particularly limited, various solvents conventionally known for non-aqueous electrolyte primary batteries can be used. Specifically, high dielectric constant solvents such as ethylene carbonate, vinylene carbonate and propylene carbonate, and these high dielectric constant solvents and diethyl carbonate, dimethyl carbonate, 1,2 dimethoxyethane, 1,2
A mixed solvent with a low boiling point solvent such as diethoxyethane can be used.

[0015]

EXAMPLES Examples of the present invention will be described below in detail with reference to comparison with comparative examples. In addition, each battery used here is
As shown in FIG. 1, it is a cylindrical battery.

The electrolyte according to the present invention has the general formula LiN
(C _X F _{2X + 1} SO ₂ ) (C _Y F _{2Y + 1} SO ₂ ) (where 1 ≦
X ≦ 4, 1 ≦ Y ≦ 4), but in this embodiment, L
iN (C ₂ F ₅ SO ₂ ) ₂ is used.

The configuration of the cylindrical battery in this embodiment will be described in detail with reference to FIG. A positive electrode mixture mainly composed of manganese dioxide is applied to an aluminum foil as a current collector,
An electrode body including a dried strip-shaped positive electrode plate 1, a strip-shaped negative electrode plate 2 made of lithium metal, and a separator 3 interposed between the positive electrode plate 1 and the negative electrode plate 2 is spirally wound. This electrode body is arranged in a case 8 as shown in FIG. In the upper opening of the outer can 8, packing 1
An assembly sealing plate 9 is mounted via the “0”, and is connected to the positive electrode plate 1 by the positive electrode lead 6. Further, an upper insulating plate 4 and a lower insulating plate 5
Is arranged.

Here, the positive electrode mixture applied to the positive electrode plate 1 is as follows:
Electrolytic manganese dioxide heat-treated as an active material, carbon powder as a conductive agent, and fluororesin powder as a binder were mixed at a weight ratio of 90: 5: 5, and an aqueous carboxymethylcellulose solution was added thereto and kneaded. It has been adjusted to a paste. A paste-like positive electrode mixture was applied to both surfaces of an aluminum foil (thickness: 20 μm) as a current collector, dried, and then formed into a sheet. Then, the sheet compact was heat-treated again at 250 ° C. to 300 ° C. to remove the attached water, thereby obtaining a positive electrode plate 1.

As a non-aqueous electrolyte, a mixed solution of propylene carbonate and 1,2-dimethoxyethane was used, and as an electrolyte, 0.5 mol of LiN (C ₂ F ₅ SO ₂ ) ₂ was used.
What was dissolved at a ratio of 1 / l was used.

The positive electrode has a width of 26 mm and a length of 400 m.
m, thickness 0.22 mm, negative electrode width 24 mm, length 4
The thickness was set to 00 mm and the thickness was set to 0.1 mm. Using these, a cylindrical non-aqueous electrolyte primary battery having an outer diameter of 17 mm, a height of 35 mm, and a battery capacity of 1300 mAh was obtained. This is designated as Battery A of the present invention.

Comparative Example 1 LiN used in the above example
In place of the non-aqueous electrolyte in which (C ₂ F ₅ SO ₂ ) ₂ was dissolved, a non-aqueous electrolyte using LiCF ₃ SO ₃ (concentration: 0.5 mol / l) as an electrolyte was used, Comparative battery 1 was prepared in the same manner as in the example.

Comparative Example 2 LiN used in the above example
Instead of the non-aqueous electrolyte in which (C ₂ F ₅ SO ₂ ) ₂ was dissolved, a non-aqueous electrolyte using LiPF ₆ (concentration: 0.5 mol / l) as an electrolyte was used. Comparative battery 2 was prepared in the same manner.

Comparative Example 3 A comparative battery 3 was prepared in which lath-shaped stainless steel (SUS444) was used as the positive electrode current collector instead of the aluminum foil positive electrode current collector used in the above example. However, the discharge capacity was the same as that of the battery of the present invention. Here, the positive electrode has a width of 26 mm, a length of 23 cm, and a thickness of 0.41.
mm, and the negative electrode had a width of 24 mm, a length of 23 cm, and a thickness of 0.17 mm.

The obtained battery A of the present invention and comparative battery 1,
The discharge characteristics and storage characteristics of each of the batteries 2 and 3 were compared.

The evaluation of the discharge characteristics of the battery is as follows. Immediately after assembling the battery, the battery discharge voltage changes and reaches a specified discharge voltage when a constant resistance discharge connected to a resistance of 60Ω is performed in a temperature atmosphere of + 20 ° C. The comparison was made in terms of the discharge duration up to.

On the other hand, the battery storage characteristics were evaluated immediately after the battery was assembled, stored at 85 ° C. for 2 weeks, and connected to a 60Ω resistor in a + 20 ° C. temperature atmosphere in the same manner as in the above-described discharge characteristics evaluation. A resistance discharge was performed, and a comparison was made in terms of changes in battery discharge voltage and discharge duration.
The test results are shown in FIGS. FIG. 2 is an initial discharge characteristic diagram immediately after the battery configuration, and FIG. 3 is a discharge characteristic diagram after storage.

From the results shown in FIG. 2, LiN (C ₂ F ₅
The battery A of the present invention and the comparative battery 2 using SO ₂ ) ₂ and aluminum foil for the positive electrode current collector maintain a discharge voltage of about 2.9 V, while the discharge voltage of the comparative battery 1 immediately after the start of the test is It is at 1.5V and then drops sharply. From this, it is clear that the battery A of the present invention and the comparative battery 2 have excellent discharge characteristics. It is considered that the discharge characteristics of the comparative battery B were significantly deteriorated immediately after the battery assembly because the aluminum foil as the positive electrode current collector eluted.

On the other hand, it is understood that the battery A of the present invention and the comparative battery 2 have a higher battery discharge voltage than the comparative battery 3 and are excellent. It is considered that the comparative battery 3 has a large electrode plate thickness and a small opposing area of the positive and negative electrodes, and therefore has a low battery discharge voltage.

Next, from the results shown in FIG. 3, LiN (C
_The battery A of the present invention using ₂ F ₅ SO ₂ ) ₂ and an aluminum foil for the positive electrode current collector has less storage deterioration and is superior to the comparative battery 2 using LiPF ₆ for the electrolyte. .

From the above results, it can be seen that the battery A of the present invention is excellent also in high-rate discharge characteristics and storage characteristics. In this embodiment, the electrolyte LiN (C ₂ F ₅ S
O ₂ ) ₂ was used, but instead of LiN (CF ₃ SO ₂ )
₂ , a general formula L such as LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ )
iN (C _X F _{2X + 1} SO ₂ ) (C _Y F _{2Y + 1} SO ₂ ) (1
≦ X ≦ 4, 1 ≦ Y ≦ 4) The same effect was obtained by using an electrolyte represented by the following formula.

[0031]

According to the present invention, manganese dioxide manganese is applied to the positive electrode.
Using lithium or lithium alloy for
In the non-aqueous electrolyte primary battery, LiN (C_XF_{2X + 1}S
O_Two) (C _YF_{2Y + 1}SO_Two) (However, 1 ≦ X ≦ 4, 1 ≦ Y
≦ 4), the use of an electrolyte
Even if a positive electrode current collector made of
The conductor does not elute into the electrolyte,
And a battery having excellent storage characteristics.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a configuration of a nonaqueous electrolyte primary battery.

FIG. 2 is a discharge characteristic diagram in an initial state immediately after a battery configuration.

FIG. 3 is a discharge characteristic diagram after storage for a certain period of time after battery construction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 Separator 4 Upper insulating plate 5 Lower insulating plate 6 Positive electrode lead 7 Negative lead 8 Case 9 Assembly sealing plate 10 Packing

Claims (1)

[Claims] 1. A non-aqueous electrolyte comprising a positive electrode having manganese dioxide as a main active material and a metal current collector, a negative electrode having lithium or a lithium alloy as an active material, and a non-aqueous electrolyte in which an electrolyte is dissolved in a non-aqueous solvent. A water electrolyte primary battery, wherein a foil or a film made of an aluminum alloy is used as the metal current collector, and LiN (C _X F _{2X + 1)} is used as the electrolyte.
_{SO 2) (C Y F 2Y} + 1 SO 2) ( provided that, 1 ≦ X ≦ 4,1
≦ Y ≦ 4) A non-aqueous electrolyte primary battery using a non-aqueous electrolyte in which at least one selected from those represented by the formula: