JPH06290794A - Nonaqueous electrolytic battery - Google Patents

Abstract

PURPOSE:To provide a nonaqueous electrolytic battery having excellence in high efficient discharging characteristic and no leak of an organic electrolyte by using in the battery a pseudo solid electrolytic nonaqueous electrolyte impregnated with the organic electrolyte. CONSTITUTION:Prescribed ratios of monomers using LiPF6 as a polymerization catalyst is added and mixed into an organic electrolyte ethylene carbonate or the like having LiPF6 as a solute contained therein. The a polymer matrix prepared by polymerizing monomers to be cured is impregnated with the organic electrolyte to form a nonaqueous electrolyte 3. A positive electrode 1 and a negative electrode 2 are arranged opposite to each other via the nonaqueous electrolyte 3, and then received respectively in both positive and negative electrode cans 4, 5 to form a nonaqueous electrolytic battery. With this constitution, the nonaqueous electrolytic battery having high ionic conductivity, excellence in high efficient discharging characteristic and no leak of the organic electrolyte can be provided.

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 battery, and more particularly to an improvement of a non-aqueous electrolyte battery for obtaining a non-aqueous electrolyte battery which has excellent high rate discharge characteristics and is free from liquid leakage. .

[0002]

2. Description of the Related Art In recent years,
Solid electrolytes made of ion-conductive polymers such as polyethylene oxide (PEO) and polypropylene oxide (PPO) have been attracting attention because of the fact that a position-free battery without liquid leakage can be obtained.

However, solid electrolytes generally have lower ionic conductivity than liquid electrolytes (usually 10 ⁻⁴ to
About 10 ^-5 S / cm), the solid electrolyte battery has a problem that poor high-rate discharge characteristics compared to a liquid electrolyte battery.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a non-aqueous electrolyte battery having excellent high rate discharge characteristics and having no liquid leakage.

[0005]

A non-aqueous electrolyte battery according to the present invention (hereinafter, referred to as "the present battery") for achieving the above object is a LiPF ₆ organic solvent containing LiPF ₆ as a solute. After adding and mixing the monomer having ₆ as a polymerization catalyst, the non-aqueous electrolyte for impregnating the organic electrolyte in the polymer matrix is used, where the monomer is polymerized and cured at room temperature or by heating. .

The monomer in the present invention is not particularly limited as long as it is a monomer that can be polymerized and cured using LiPF ₆ as a polymerization catalyst at a temperature at which the organic electrolyte solution is not evaporated. Specific examples of such a monomer include 1,3-dioxolane, 4-methyl-1,3-dioxolane, tetrahydrofuran and 2-methyltetrahydrofuran.

The suitable addition ratio of the above-mentioned monomer to the organic electrolytic solution depends on the monomer used. When 1,3-dioxolane is used as the monomer, a suitable addition ratio is 5 to 35 g with respect to 100 cc of the organic electrolyte.
Is the range. If the amount is less than 5 g, the polymer matrix produced will not be sufficiently developed and the curing will be insufficient, so that the liquid leakage preventing effect cannot be expected sufficiently. On the other hand, when it exceeds 35 g, the impregnation ratio of the organic electrolytic solution is relatively lowered, so that the ionic conductivity is deteriorated.

The polymerization reaction of the above-mentioned monomer will be shown by taking the case of using 1,3-dioxolane as an example.
, And the polymerization reaction in this case is ring-opening polymerization of cyclic ether.

[0009]

[Chemical 1]

As the organic electrolyte solution to which the above-mentioned monomers are added and mixed, organic solvents such as ethylene carbonate, vinylene carbonate and propylene carbonate, and these and dimethyl carbonate, diethyl carbonate, 1,
0.7 to 1.5 M (mol / liter) of LiPF ₆ in a mixed solvent with a low boiling point solvent such as 2-dimethoxyethane, 1,2-diethoxyethane and ethoxymethoxyethane.
An example is a solution dissolved at a ratio of. In addition, LiPF ₆
When it is difficult for the monomer polymerization reaction to proceed, AlC
Other polymerization catalysts such as l ₄ may be added and mixed separately.

As described above, according to the present invention, an organic electrolytic solution is obtained by adding and mixing a monomer to an organic electrolytic solution containing LiPF ₆ as a solute and polymerizing and curing the monomer using LiPF ₆ as a polymerization catalyst. It is characterized by using a non-aqueous electrolyte that is impregnated in a polymer matrix. Therefore, other members constituting the battery such as the positive electrode material and the negative electrode material are not particularly limited, and various materials conventionally used for the non-aqueous electrolyte battery or proposed can be used without limitation. Is.

For example, as the positive electrode material (active material),
LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiFe
O ₂ is mentioned as a suitable one.

Examples of the negative electrode material include carbon materials such as graphite and coke, and metal oxides. Among the carbon materials, in order to obtain a battery with a large discharge capacity, the d value (d ₀₀₂ ) on the lattice plane (002) plane is less than 3.37 Å and the crystallite size (Lc) in the c-axis direction is 200 Å or more. Particularly preferred is graphite having high crystallinity.

[0014]

In the battery of the present invention, a nonaqueous electrolyte, which should be referred to as a pseudo solid electrolyte impregnated with an organic electrolyte, is used, so that the ionic conductivity is high, and the organic electrolyte is in a polymer matrix of the nonaqueous electrolyte. Since it is taken in, the leakage does not occur.

[0015]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited by the following examples, and various modifications can be made without departing from the scope of the invention. Is possible.

(Example) A flat rectangular non-aqueous electrolyte battery (the battery of the present invention) was produced.

[Positive electrode] LiCoO ₂ as a positive electrode active material
Then, artificial graphite as a conductive agent and polytetrafluoroethylene were mixed at a weight ratio of 90: 5: 5 to obtain a positive electrode mixture. Then, the positive electrode mixture is molded at a molding pressure of 2 ton / cm ^2.
After being pressure-molded in, a heat treatment was performed at 250 ° C. to prepare a positive electrode. A stainless steel plate (SUS304) was used as the positive electrode current collector.

[Negative Electrode] Natural graphite as a negative electrode material and polytetrafluoroethylene as a binder were mixed in a weight ratio of 95: 5 to obtain a negative electrode mixture. Then, this negative electrode mixture was pressure-molded at a molding pressure of 2 ton / cm ² , and then 25
A heat treatment was performed at 0 ° C. to prepare a negative electrode. A stainless steel plate (SUS304) was used as the negative electrode current collector.

[Non-Aqueous Electrolyte] LiPF ₆ (purity 99.9%) is added to 0.5 M in a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) in an equal volume.
To prepare an organic electrolyte solution. Next, 50 cc of 1,3-dioxolane (monomer) was added to and mixed with 500 cc of this organic electrolytic solution to prepare a non-aqueous electrolyte (uncured slurry).

[Production of Battery] The above uncured slurry was applied to the positive electrode and the negative electrode by the doctor blade method so as to have a thickness of 10 μm, the application surfaces of both electrodes were overlapped, and heated at 60 ° C. for 2 hours to obtain a non-aqueous system The electrolyte was cured. This was housed in a battery can to produce a flat rectangular battery BA1 of the present invention (battery size: length and width 10 × 5 cm, thickness 0.5 mm).

FIG. 1 is a sectional view schematically showing the manufactured battery BA1 of the present invention. The battery BA1 of the present invention shown in FIG.
Positive electrode 1, negative electrode 2, non-aqueous electrolyte 3 also serving as a separator for separating these electrodes 1, 2 from each other, positive electrode can 4, negative electrode can 5, positive electrode current collector 6, negative electrode current collector 7, and polypropylene insulating packing 8 And so on.

The positive electrode 1 and the negative electrode 2 are housed in a battery case formed by positive and negative bipolar cans 4 and 5 facing each other with a non-aqueous electrolyte 3 impregnated with an organic electrolytic solution, and the positive electrode 1 is a positive electrode current collector. The negative electrode 2 is connected to the positive electrode can 4 via the body 6, and the negative electrode 2 is connected to the negative electrode can 5 via the negative electrode current collector 7, and the chemical energy generated inside the battery is transferred from both terminals of the positive electrode can 4 and the negative electrode can 5 to electrical energy. It can be taken out as.

Comparative Example 1 250 cc of a methyl ethyl ketone (MEK) solution of polyoxymethylene resin (resin solid content: 10% by weight), 250 cc of a mixed solvent of EC and DMC in an equal volume, and LiPF ₆ at a ratio of 0.5M. The slurry obtained by mixing the dissolved organic electrolytic solution was applied on a glass plate by a doctor blade method to a thickness of 10 μm, and the temperature was 60 ° C.
MEK was evaporated by drying for 2 hours to form a thin film solid electrolyte on a glass plate. Then, this solid electrolyte was housed in a battery can in a state of being sandwiched between a positive electrode and a negative electrode similar to those used in the previous example, and the comparative battery B
C1 was produced.

Comparative Example 2 Polyoxymethylene resin in methyl ethyl ketone (MEK) solution (resin solid content: 10% by weight) 250 cc, acetonitrile 250 cc Li
A slurry obtained by mixing an organic electrolyte solution in which PF ₆ was dissolved at a ratio of 0.5M was applied on a glass plate by a doctor blade method to a thickness of 10 μm, and dried at 60 ° C. for 2 hours to obtain MEK and acetonitrile. Was evaporated to form a thin film solid electrolyte on the glass plate. Then, this solid electrolyte was housed in a battery can in a state of being sandwiched between a positive electrode and a negative electrode similar to those used in the previous example, and the comparative battery B
C2 was produced.

[Discharge Capacity of Each Battery] First, at room temperature (25 °
Under C), the battery was charged to 20 V at an end-of-charge voltage of 4.2 V and then discharged at 20 mA to an end-of-discharge voltage of 2.5 V. Then, the battery was charged again at 20 mA to a charge end voltage of 4.2 V, and then discharged at various currents, and the discharge capacity of each battery was examined. The results are shown in Figure 2.

FIG. 2 is a graph showing the discharge capacities at various discharge currents of each battery, with the vertical axis representing the discharge capacity (mAh) and the horizontal axis representing the discharge current (mA).
It can be seen that the battery BA1 of the present invention using the pseudo solid electrolyte impregnated with the organic electrolyte is superior in high rate discharge characteristics to the comparative batteries BC1 and BC2 using the solid electrolyte.

In the above embodiments, the case where the present invention is applied to the flat rectangular non-aqueous electrolyte battery has been described as an example, but the shape of the battery is not particularly limited, and various types such as a cylindrical type and a coin type are used. It is applicable to a non-aqueous electrolyte battery having the above shape, and it is not particularly limited whether the battery is a primary battery or a secondary battery.

Further, in the embodiment, a lithium battery using lithium ions as charge carriers has been described as an example, but the present invention is not limited to the above, but other alkali metal ions such as sodium ions or alkaline earth metal ions such as calcium ions. It can also be applied to a non-aqueous electrolyte battery or the like in which is used as a charge carrier.

Further, in the examples, the monomer was polymerized and cured on the electrode in order to reduce the interfacial resistance between the electrode and the non-aqueous electrolyte, but the present invention is not limited to such a constitution, and the non-aqueous electrolyte may be a glass. It may be formed as a thin film on a plate or the like and loaded between the positive electrode and the negative electrode.

[0030]

Since the non-aqueous electrolyte impregnated with the organic electrolytic solution is used in the battery of the present invention, the present invention exhibits excellent unique effects such as excellent high rate discharge characteristics and no leakage.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a flat rectangular non-aqueous electrolyte battery (the battery of the present invention).

FIG. 2 is a graph showing discharge capacities when the respective non-aqueous electrolyte batteries produced in Examples and Comparative Examples were discharged at various currents.

[Explanation of symbols]

 BA1 non-aqueous electrolyte battery (the battery of the present invention) 1 positive electrode 2 negative electrode 3 separator

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Toshihiko Saito 2-18 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (2)

[Claims] 1. A polymer matrix prepared by adding and mixing a monomer having LiPF ₆ as a polymerization catalyst to an organic electrolyte solution containing LiPF ₆ as a solute, and polymerizing and curing the monomer at room temperature or by heating. A non-aqueous electrolyte battery comprising a non-aqueous electrolyte impregnated with the organic electrolytic solution. 2. The monomer is 1,3-dioxolane, 4
The non-aqueous electrolyte battery according to claim 1, which is -methyl-1,3-dioxolane, tetrahydrofuran or 2-methyltetrahydrofuran.