JPH097609A - Nonaqueous battery - Google Patents

Abstract

PURPOSE: To provide a nonaqueous battery in which the impregnating ability of a nonaqueous electrolyte to a separator is enhanced and various characteristics are enhanced by using a nonaqueous electrolyte containing the predetermined quantity of a specific carbonate compound. CONSTITUTION: A nonaqueous battery is constituted of an positive electrode, a negative electrode, a separator, a nonaqueous electrolyte and the like. When the nonaqueous electrolyte and at least one kind and 0-1 to 10wt.% of a carbonate compound expressed by a formula is contained, impregnating ability of a nonaqueous electrolyte to a separator is enhanced, and a nonaqueous battery in which a battery capacity and a battery voltage are large, dispersion of performance is reduced and various characteristics are enhanced is obtained. In the formula, (n) is 0 or 1, R1 and R3 alkylene radicals having the number of carbon atoms of 1 to 30 when n=0 and the number of carbon atoms in a party is not less than 8 when R1 and R3 are alkylene radicals and when n=1, R1 and R3 are the alkylene radicals having the number of carbon atoms of 1 to 30 and R2 is 1, 2 alkylene radicals having the number of carbon atoms of 2 to 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is excellent in impregnation of a separator with a non-aqueous electrolyte, has a large battery capacity, and
The present invention relates to a non-aqueous battery having a high battery voltage.

[0002]

2. Description of the Related Art In recent years,
It is desired that the primary battery and the secondary battery have a small size and a high capacity, and studies are being made to reduce the size and the capacity from various viewpoints such as a positive electrode active material, a negative electrode active material, an electrolytic solution, and a battery structure. There is.

The selection of a separator is also important for achieving such a small size and high capacity of the battery. Since the volume of the separator with respect to the battery is proportional to the thickness of the separator, the thickness of the separator should be as thin as possible. Is desired.

Papers, woven fabrics, glass mats, etc., which have been conventionally used as separators, require a certain thickness or more due to problems of strength, prevention of short circuit, etc., which is a great obstacle to achieving miniaturization of batteries. Was there.

Therefore, it has been proposed to use a nonwoven fabric or a porous membrane made of a thermoplastic resin such as polyethylene or polypropylene as the separator. By using a thermoplastic resin as the material of the separator, the strength and short-circuit prevention effect are increased, and even if the thickness of the separator is reduced, it has the characteristics that it can withstand practical use. Has become an essential entity.

However, a separator made of a thermoplastic resin has a drawback that it has a poor impregnation property with a non-aqueous electrolyte, and
Carbonic acid ester compounds such as ethylene carbonate and propylene carbonate, which have the property of withstanding high voltage,
Since this defect becomes prominent when a non-aqueous electrolytic solution containing a cyclic ester compound such as γ-butyrolactone as a solvent is used, the impregnation step of the non-aqueous electrolytic solution becomes complicated, which is a problem in the manufacturing process. Not only that, there was a problem such as variation in battery performance due to poor impregnation of the non-aqueous electrolyte.

For this reason, attempts have been made to add a surfactant to the non-aqueous electrolyte to improve the wettability of the non-aqueous electrolyte with respect to the separator, but in this case, the adverse effect on the battery performance is large. , Was not satisfactory in practice. Therefore, in JP-A-2-244565, a phosphorus-containing compound selected from an organic phosphate, an organic phosphite or an organic phosphonate compound is added to a non-aqueous electrolyte as an additive that does not exert such a bad influence. However, the effect of improving the wetting property when such a phosphorus-containing compound is added to the non-aqueous electrolyte is still insufficient. Moreover, when a large amount of a phosphorus-containing compound is added, not only the characteristics of the non-aqueous electrolyte are adversely affected, but also the phosphorus-containing compound may be deposited on the surface of the separator and block the voids. However, there was a large variation and it was not satisfactory in practical use.

Therefore, when a separator made of a thermoplastic resin is used, it has been strongly desired to improve the impregnation property of the non-aqueous electrolyte without adversely affecting the characteristics of the battery.

Therefore, an object of the present invention is to provide a non-aqueous battery which is excellent in impregnation property of a non-aqueous electrolyte into a separator, has a large battery capacity and battery voltage, and has no fluctuation in performance.

[0010]

As a result of various studies, the present inventors have found that the above object can be achieved by adding a specific carbonate compound to a non-aqueous electrolyte.

The present invention has been made on the basis of the above findings, and is a battery having at least a positive electrode, a negative electrode, a separator and a non-aqueous electrolytic solution as constituent elements, wherein the non-aqueous electrolytic solution is represented by the following [Chemical formula 2] ( The same as the above [Chemical formula 1])
0.01 to at least one compound represented by (I)
The non-aqueous battery is characterized by containing 10% by weight.

[0012]

Embedded image

The non-aqueous battery of the present invention will be described in detail below. In the compound represented by the general formula (I) used in the present invention, the alkyl group having 1 to 30 carbon atoms represented by R ₁ and R ₃ in the general formula (I) is, for example, methyl, Ethyl, propyl, butyl, pentyl,
Examples thereof include linear or branched alkyl groups such as hexyl, heptyl, octyl, isooctyl, 2-ethylhexyl, isononyl, decyl, isodecyl, undecyl, lauryl, myristyl, palmityl, stearyl, isostearyl, docosyl, behenyl, triacontyl and decenyl. .

Further, as the 1,2-alkylene group having 8 to 30 carbon atoms in which R ₁ and R ₃ in the above general formula (I) are bonded,
1,2-octylene, 1,2-nonylene, 1,2-decene, 1,2-undecene, 1,2-dodecene, 1,2-tetradecene, 1,2-hexadecene, 1,2-octadecene, etc. To be

As the 1,2-alkylene group having 2 to 30 carbon atoms represented by R ₂ in the above general formula (I), those exemplified above as the alkylene group in which R ₁ and R ₃ are bonded are Other examples include ethylene, 1,2-propylene, 1,2-butylene, 1,2-pentylene, 1,2-hexylene, and 1,2-heptylene.

Therefore, as the compounds represented by the above general formula (I) used in the present invention, the following compounds No. 1 to No. 5 are specifically exemplified. However, the present invention is in no way limited to these compounds.

[0017]

Embedded image

[0018]

Embedded image

[0019]

Embedded image

[0020]

[Chemical 6]

[0021]

[Chemical 7]

The addition amount of the compound represented by the general formula (I) used in the present invention is as follows.
It is 0.01 to 10% by weight, particularly preferably 0.05 to 5% by weight, and particularly preferably 0.2 to 3% by weight. If the above-mentioned addition amount is less than 0.01% by weight, the effect due to the addition is scarcely recognized, and even if it exceeds 10% by weight, the effect corresponding to the addition amount is not improved and it is economically disadvantageous. Become.

The method of synthesizing the compound represented by the above general formula (I) used in the present invention is not particularly limited, and examples thereof include transesterification of diphenyl carbonate and alcohol, reaction of phosgene and alcohol. Any of the commonly used synthetic methods such as the reaction of a chloroformate with an alcohol may be used. The production methods of the compounds used in the examples of the present invention are shown below.

Synthesis of Compound No. 1 37.2 g (0.2 mol) of n-dodecanol, 26.9 g (0.22 mol) of 4-dimethylaminopyridine and 200 ml of toluene were charged and cooled to 10 ° C. or lower. To this solution, 20.8 g (0.22 mol) of methyl chloroformate was added dropwise over 20 minutes. Then, after reacting at 60 ° C. for 5 hours,
The reaction solution was washed with water to remove 4-dimethylaminopyridine hydrochloride. After adjusting the pH to 2 with a 1N aqueous hydrochloric acid solution, washing with water was repeated until the aqueous layer became neutral. Then, the toluene layer was dehydrated with anhydrous sodium sulfate, and the toluene was distilled off,
From the obtained liquid material, 15.6 g (yield 32.0%) of the target product was obtained by distillation at 105 to 106 ° C./3 mmHg.
When the obtained target product was analyzed by gas chromatography, the purity was 99.6%. Moreover, the absorption at 1740 cm ⁻¹ based on C═O was confirmed by the infrared absorption spectrum.

Synthesis of Compound No. 2, 10.1 g (0.05 mol) of 1,2-dodecanediol, 4-
Dimethylaminopyridine (14.6 g, 0.12 mol) and toluene (70 ml) were charged, cooled to 10 ° C or lower, and methyl chloroformate (14.2 g, 0.15 mol) was added.
It was added dropwise at 2 to 16 ° C. Then, after reacting at 60 ° C. for 5 hours, the reaction solution was washed with water to remove 4-aminopyridine hydrochloride. After adjusting the pH to 2 with a 1N aqueous hydrochloric acid solution, washing with water was repeated until the aqueous layer became neutral. Then, the toluene layer was dehydrated with anhydrous sodium sulfate, and toluene was distilled off. The residue was dissolved in 100 ml of xylene and 0.2 g (0.001 mol) of 28% methanol solution of sodium methoxide was added.
Was added and the reaction was carried out under reflux of xylene. After washing with water and dehydration with anhydrous sodium sulfate, distilling off xylene under reduced pressure, 1
4.4 g (yield 38%) of the target product was obtained at 38 to 140 ° C./0.4 mmHg. When the obtained target product was analyzed by gas chromatography, the purity was 96.0%.
In addition, according to the infrared absorption spectrum, 180 based on C = O
Absorption at 0 cm ^-1 was confirmed.

Synthesis of Compound No. 3, 10.1 g (0.05 mol) of 1,2-dodecanediol, 4
-Dimethylaminopyridine 14.6 g (0.12 mol)
And 150 ml of toluene were charged, and after cooling to 10 ° C or lower, 14.2 g (0.15 mol) of methyl chloroformate
Was added dropwise at 10 to 16 ° C. Then, after reacting at 60 ° C. for 5 hours, the reaction solution was washed with water to remove 4-aminopyridine hydrochloride. After adjusting the pH to 2 with a 1N aqueous hydrochloric acid solution, washing with water was repeated until the aqueous layer became neutral. Then, the toluene layer is dehydrated with anhydrous sodium sulfate, and the toluene is distilled off under reduced pressure, followed by the target product 4.4 at 138 to 140 ° C./0.4 mmHg.
g (yield 39%) was obtained. When the obtained target product was analyzed by gas chromatography, the purity was 96.0%. Moreover, the absorption at 1750 cm ⁻¹ based on C═O was confirmed by the infrared absorption spectrum.

The other constituents of the non-aqueous battery of the present invention, that is, the positive electrode, the negative electrode, the non-aqueous electrolytic solution (non-aqueous electrolyte and solvent), the separator, etc., are not particularly limited, and are conventionally used in the non-aqueous battery. The various materials used can be used as they are.

For example, as the positive electrode active material constituting the positive electrode, TiS ₂ , TiS ₃ , MoS ₃ , FeS ₂ , Li _{(1 -x)} MnO ₂ , Li _(1-x)
Examples include CoO ₂ , Li _(1-x) NiO ₂ , V ₂ O ₅ , V ₆ O ₁₃ (x is 0 ≦ x ≦ 1), and the negative electrode active material forming the negative electrode includes lithium and lithium. Examples include alloys, carbonaceous materials, and conductive polymers.

As the non-aqueous electrolyte of the non-aqueous electrolyte,
LiClO ₄ , LiBF ₄ , LiAsF ₆ , CF ₃ SO ₃ Li, LiPF ₆ , LiI, L
Examples thereof include iAlCl ₄ , NaClO ₄ , NaBF ₄ , NaI and the like.

As the solvent used for the non-aqueous electrolytic solution, ether compounds, ketone compounds, nitrile compounds,
Examples thereof include halogenated hydrocarbon compounds, carbonate compounds, cyclic ester compounds, sulfolane compounds, and the like, specifically, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, anisole, monoglyme,
4-methyl-2-pentanone, acetonitrile, propionitrile, butyronitrile, valeronitrile, benzonitrile, 1,2-dichloroethane, ethylene carbonate, propylene carbonate, ethylene glycol dimethyl carbonate, propylene glycol dimethyl carbonate, ethylene glycol diethyl carbonate,
Examples thereof include vinylene carbonate, γ-butyrolactone, sulfolane, 3-methylsulfolane, methyl formate, dimethylformamide, dimethylthioformamide, dimethyl sulfoxide, and the like, or a mixture of a plurality of these.

As the separator, it is preferable to use a thermoplastic resin separator. Examples of the thermoplastic resin used for manufacturing the thermoplastic resin separator include high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene, polybutene-1, poly-3-methylpentene, ethylene-
Examples include polyolefins such as propylene copolymers, fluororesins such as polytetrafluoroethylene, polystyrene, polymethylmethacrylate, polydimethylsiloxane and the like, and mixtures thereof. In particular, polyolefins have molding processability, chemical resistance and mechanical properties. It is preferable from the viewpoint of strength and the like.

Further, the above thermoplastic resin separator comprises a low melting point thermoplastic resin film and a high melting point thermoplastic resin film or a non-woven fabric in order to prevent the battery contents from spouting or exploding due to heat generation due to a short circuit. It may have a multilayer structure such as a laminated structure.

The non-aqueous battery of the present invention having the above structure can be used as a primary or secondary battery, and its shape is not particularly limited, and may be flat type (button type), cylindrical type, square type. It can be used as a battery of various shapes such as a mold.

[0034]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples, and can be appropriately modified and implemented within the scope of the invention.

Example 1 Needle coke having a BET specific surface area of 11 m ² / g and a true density of 2.13 g / cm ³ was ground by a ball mill to an average particle size of 10 μ, and 1 part by weight of this powder and 4 parts of polyacrylonitrile were used.
After mixing 1 part by weight of a dimethylformamide solution of 10%, a negative electrode was manufactured by forming a film having a thickness of 75 μ on both surfaces of a copper foil having a thickness of 10 μ.

Further, LiCoO ₂ was ball-milled to have an average particle size of 3 μm.
After crushing into 1 part by weight of this powder, graphite 0.
05 parts by weight, 0.05 parts by weight of acetylene black, and 1 part by weight of a 2% dimethylformamide solution of polyvinylidene fluoride were mixed, and 1 part was formed on both sides of a 15 μ thick aluminum foil.
A positive electrode was manufactured by forming a film having a thickness of 00 μ.

A non-woven fabric (thickness 150 μ, thread diameter 3 μ) made of polyethylene was used as a separator, and a cylindrical battery was assembled using the above positive electrode and negative electrode. Then, in this battery, as an electrolytic solution, 1M LiPF ₆ propylene carbonate / ethylene carbonate (1: 1
(Volume) A nonaqueous electrolytic solution containing 2% by weight of Compound No. 1 as an affinity improving agent for a separator was injected by a normal pressure impregnation method to obtain a nonaqueous battery of the present invention.

Using 100 of this non-aqueous battery, 1A, 4.
1A after charging in 2V constant current / constant voltage mode for 5 hours
The discharge capacity when discharged to 2.7 V at a constant current is shown in the following [Table 1]. In addition, the number of batteries having a discharge capacity of 20% or more less than the average value is shown as variation in Table 1 below. The wettability of the non-aqueous electrolyte and the separator was evaluated by the contact angle, and the results are shown in [Table 1] below.

Examples 2 to 8 and Comparative Examples 1 to 3 Nonaqueous batteries were prepared in the same manner as in Example 1 except that the affinity improver shown in the following [Table 1] was used. Was tested. The results are shown in the following [Table 1].

[0040]

[Table 1]

Example 9 A 250 mesh stainless steel in which a nickel plate was spot-welded to the end of a positive electrode binder obtained by kneading 90 parts by weight of manganese dioxide powder, 5 parts by weight of graphite and 5 parts by weight of polytetrafluoroethylene. A positive electrode sheet having a thickness of 0.5 mm was manufactured by coating on a net.

A negative electrode was manufactured by pressure-bonding a stainless steel net as a lead tab to a lithium foil having a thickness of 0.2 mm.

A cylindrical battery was assembled using a microporous membrane (thickness: 50 μ, average pore size: 0.4 μ) made of polypropylene as a separator and the above positive electrode sheet and negative electrode. Then, as an electrolytic solution, 1
A nonaqueous electrolytic solution containing 2% by weight of compound No. 1 as an affinity improver added to a propylene carbonate solution of lithium perchlorate having an M concentration was injected by an atmospheric pressure permeation method to obtain a nonaqueous battery of the present invention.

The discharge capacity when 100 non-aqueous batteries were discharged at a constant current of 1 A to 1.5 V was as shown in Table 2 below.
It was shown to. In addition, the number of batteries having a discharge capacity of 20% or more less than the average value is shown as variation in Table 2 below.

Examples 10 to 11 and Comparative Examples 4 to 6 A battery was prepared in the same manner as in Example 9 except that the affinity improver shown in the following [Table 2] was used, and the same test as in Example 9 was performed. I went. The results are shown in [Table 2] below.

[0046]

[Table 2]

As is clear from the results shown in [Table 1] and [Table 2] above, when a non-aqueous electrolyte containing a compound represented by the general formula (I) was used (Examples 1 to 1). 11)
Has a large battery capacity and shows almost no variation in performance. On the other hand, when the non-aqueous electrolyte solution containing no affinity improver was used (Comparative Examples 1 and 4), the battery capacity was When the non-aqueous electrolyte containing the affinity improver other than the compound represented by the general formula (I) was used (Comparative Examples 2, 3, 5 and 6), the battery capacity was improved. However, there is a large variation in performance, and it is not possible to stably manufacture a high quality non-aqueous battery.

[0048]

INDUSTRIAL APPLICABILITY The non-aqueous battery of the present invention is excellent in the impregnation property of the non-aqueous electrolytic solution into the separator, has a large battery capacity and battery voltage, and has no variation in performance.

Claims (1)

[Claims] 1. A battery having at least a positive electrode, a negative electrode, a separator and a non-aqueous electrolyte as constituent elements, wherein the non-aqueous electrolyte is at least a compound represented by the following general formula (I). A non-aqueous battery containing one of 0.01 to 10% by weight. Embedded image