JP2002203545A - Non-aqueous electrolytic solution battery and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-aqueous electrolytic solution battery which can prevent a liquid leakage or the like caused by generation of carbon dioxide by suppressing that an internal resistance of a battery becomes high, and even if the battery is exposed to a high temperature, by suppressing that niobium oxide and electrolytic solution will react. SOLUTION: In the non-aqueous electrolytic solution battery having a positive electrode 1 wherein a compound which can insert and remove lithium is taken as a positive electrode active substance, a negative electrode 2 wherein the material enabled to insert and remove lithium is taken as a negative electrode active substance, and the non-aqueous electrolytic solution, that which is calcined at a state that niobium oxide and boron oxide are mixed is used as the positive electrode active substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a positive electrode using a compound capable of inserting and removing lithium as a positive electrode active material, a negative electrode using a material capable of inserting and removing lithium as a negative electrode active material, and a non-aqueous electrolyte. The present invention relates to a non-aqueous electrolyte battery having the same and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, a non-aqueous electrolyte battery has been receiving attention as a battery having a high energy density. As such a non-aqueous electrolyte battery, for example, a manganese oxide such as manganese dioxide is used for a positive electrode. On the other hand, for the negative electrode, lithium alone, lithium-aluminum alloy,
Alternatively, a carbon material or the like is being studied. Batteries using these positive and negative electrode materials have a charge / discharge voltage of 3 V or more.

On the other hand, in recent years, there has been a demand for a portable information device to be smaller and lighter and extend the usable time, and by reducing the operating voltage of the device and reducing power consumption, It responds to these conflicting requirements. 2. Description of the Related Art Conventionally, the charge / discharge voltage of a battery used as various power supplies of the above-mentioned device is determined by the operating voltage of a semiconductor element mounted on the device.
Since it is about 3V, it was set to 3V or more.
However, with the improvement of semiconductor devices used in equipment,
The operating voltage has dropped to about 2.6V, and has recently been set to 2V or less. For this reason, it is desired that batteries used in these devices also have a characteristic that can be charged even at a voltage of 2 V or less in response to a decrease in the operating voltage of the element.

[0004] In consideration of the above, a battery using niobium oxide as a positive electrode active material has been proposed (for example, see Japanese Patent Application Laid-Open No. 2000-133313). However, when niobium oxide is used as the positive electrode active material, the internal resistance of the battery becomes higher than when manganese dioxide is used as the positive electrode active material. In addition, when the battery is exposed to a high temperature, there is a problem that the niobium oxide reacts with the electrolytic solution to generate carbon dioxide gas and cause a liquid leakage or the like.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned conventional problems, and has as its object to suppress the internal resistance of a battery from becoming high, A non-aqueous electrolyte battery capable of suppressing reaction between niobium oxide and an electrolyte even when exposed to high temperatures and preventing liquid leakage and the like caused by generation of carbon dioxide gas, and a non-aqueous electrolyte battery therefor. It is to provide a manufacturing method.

[0006]

A non-aqueous electrolyte battery according to the present invention for achieving the above object comprises a positive electrode using a compound capable of inserting and removing lithium as a positive electrode active material, and a material capable of inserting and removing lithium. In a non-aqueous electrolyte battery having a negative electrode having a negative electrode active material and a non-aqueous electrolyte, a battery containing niobium oxide and boron oxide is used as the positive electrode active material. According to the above configuration, even when the internal resistance is low and the battery is exposed to a high temperature, generation of carbon dioxide gas can be suppressed.

It is not clear why the internal resistance of the battery is low, but it is necessary to use niobium oxide having a particle size smaller than that of manganese dioxide and containing niobium oxide and boron oxide as a positive electrode active material. If used, boron oxide is present to some extent on the surface of niobium oxide. From these facts, it is considered that niobium oxide particles are likely to be adjacent to each other, and that the boron oxide present on the surface of the niobium oxide acts as a conductive film by containing the solvent of the electrolytic solution. Further, the reason why the generation of carbon dioxide gas can be suppressed is that, as described above, the surface of niobium oxide contains boron oxide to some extent, and a part of the surface of niobium oxide is covered with boron oxide. It is considered that this is because the area where the niobium oxide comes into contact with the electrolytic solution is reduced, and the side reaction with the electrolytic solution is suppressed.

Japanese Patent Application Laid-Open No. 9-129228 discloses a method in which manganese dioxide is coated with boron oxide, and Japanese Patent Application Laid-Open No. 9-265988 discloses a method in which the surface of LiMnO ₂ particles is coated with boron. In this document, LiCoO _{2 having} a surface coated with boron has been proposed. However, in these prior arts, when the amount of boron oxide (boron) is large, the battery capacity is so small that it cannot be practically used, whereas in the configuration of the present invention, the amount of boron oxide (boron) is small. There is an advantage that even if the battery capacity is increased to some extent, the battery capacity can be prevented from being reduced. This is apparent from claim 3 below.

A second aspect of the present invention is characterized in that, in the first aspect of the present invention, the positive electrode active material dissolves the boron oxide and adheres to the niobium oxide surface. If the boron oxide dissolves and adheres to the niobium oxide surface as in the above configuration, the adhesive force between the two increases, and the effect described in claim 1 is further exhibited.

[0010] The invention according to claim 3 is the invention according to claim 1 or 2, wherein the atomic ratio of boron to niobium is 0.04 or more and 0.38 or less (particularly 0.12 or more and 0.3 or less).
8 or less), the addition ratio of the boron oxide to the niobium oxide is regulated. The regulation as described above is that when the atomic ratio of boron to niobium is less than 0.04, the addition amount of boron oxide is too small, the internal resistance of the battery is not sufficiently reduced, and carbon dioxide gas is generated. On the other hand, when the atomic ratio of boron to niobium exceeds 0.38, the amount of boron oxide added is too large (that is, the relative amount of niobium oxide decreases). This is because there is a problem that the battery capacity is reduced.

The invention described in claim 4 is the first to third inventions.
In the described invention, the battery, in addition to the positive and negative electrodes and the non-aqueous electrolyte, has an outer can, a sealing lid, and an insulating gasket interposed between the outer can and the sealing lid to seal the battery. The insulating gasket is made of a polymer material having an aromatic ether, aromatic sulfide, or aromatic ester structure in the main chain. The polymer material is
In particular, since the gasket is caulked by the outer can and the sealing lid and has excellent heat resistance under pressure, a good insulating gasket can be obtained. Therefore, a battery suitable for a reflow method in which surface mounting is performed by exposing to a high-temperature environment is obtained.

A non-aqueous electrolyte battery according to the present invention for achieving the above object has a step of producing a positive electrode active material by firing in a state where a boron compound and niobium oxide are mixed. It is characterized by. When the positive electrode active material is manufactured by the above method, boron oxide dissolves and adheres to the niobium oxide surface. Therefore, the internal resistance is low,
In addition, the nonaqueous electrolyte battery of the present invention, which can suppress the amount of carbon dioxide gas generated at high temperatures, can be easily manufactured.
The invention according to claim 6 is the invention according to claim 5, wherein the boron compound is boric oxide or boric acid.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments at all, and may be carried out with appropriate changes within the scope of the gist of the present invention. It is possible.

(Preparation of Positive Electrode) First, firing at 1000 ° C.
Niobium oxide (Nb_Two0_Five) With boron oxide (B_TwoO _Five)
Is mixed and then calcined at 375 ° C. for 1 hour,
A positive electrode active material was produced. At this time, boron to niobium
Has an atomic ratio of 0.20 (hereinafter referred to as B / Nb ratio)
(The amount ratio is 5 wt%) with respect to the niobium oxide.
Then, the above boron oxide was added. Next, the positive electrode active material
And acetylene black as a conductive agent, and as a binder
Mixed with all fluororesins at a mass ratio of 90: 5: 5.
The positive electrode is pressed by forming the combined
Produced.

(Preparation of Negative Electrode) A rolled sheet of metallic lithium having a predetermined thickness was punched into a disk to prepare a negative electrode.

(Preparation of Non-Aqueous Electrolyte Solution) LiN (CF ₃ SO ₂ ) ₂ was mixed with 1 M of LiN (CF ₃ SO ₂ ) ₂ in an equal volume mixed solvent of propylene carbonate (PC) and 1,2-dimethoxyethane (DME).
(Mol / liter) to prepare a non-aqueous electrolyte.

(Preparation of Battery) A flat type battery of the present invention was prepared using the above positive and negative electrodes and a non-aqueous electrolyte (battery dimensions: diameter 4.0 mm, thickness 1.4 mm). As the separator, a non-woven fabric made of polyphenylene sulfide was used, which was impregnated with the above-mentioned non-aqueous electrolyte.

FIG. 1 is a cross-sectional view schematically showing a manufactured battery of the present invention. The battery of the present invention shown in FIG. 1 includes a positive electrode 1, a negative electrode 2, a separator 3 for separating these electrodes 1 and 2 from each other, It comprises a positive electrode can 4, a negative electrode can 5, and an insulating packing 6 made of polyphenylene sulfide.

The positive electrode 1 and the negative electrode 2 are housed in a battery case formed with positive and negative bipolar cans 4 and 5 facing each other via a separator 3 impregnated with a non-aqueous electrolyte. The negative electrode 2 is connected to a negative electrode can 5 so that chemical energy generated inside the battery can be taken out from both terminals of the positive electrode can 4 and the negative electrode can 5 as electric energy.

Here, the insulating packing is not limited to the above-mentioned polyphenylene sulfide, but a polymer having an aromatic ether or aromatic sulfide or aromatic ester structure in the main chain such as polyetheretherketone or polyetherketone. Any material is acceptable.

Examples of the negative electrode in the present invention include, in addition to the above-mentioned lithium alloy, those using metal lithium and an alloy or a carbon material capable of occluding and releasing lithium ions as an electrode material. Further, the solvent of the electrolytic solution is not limited to the above, ethylene carbonate, vinylene carbonate, γ-butyrolactone, sulfolane,
A high-boiling organic solvent such as 3-methylsulfolane or a mixed solvent thereof with a low-viscosity low-boiling organic solvent such as diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, tetrahydrofuran, 1,2-dimethoxyethane, or ethoxymethoxyethane; A mixed solvent obtained by mixing two or more kinds of high-boiling organic solvents can be used. Further, as the electrolyte of the electrolytic solution, the above-mentioned LiN (CF ₃ SO ₂ ) ₂
, LiPF ₆ , LiAsF ₆ , LiClO ₄ , Li
BF ₄ , LiCF ₃ SO ₃ , LiN (C ₂ F ₅ SO ₂ )
₂ etc. can be used.

In addition, the present invention is not limited to a coin-type non-aqueous electrolyte battery, but can be applied to other non-aqueous electrolyte batteries.

[0023]

EXAMPLES (Example 1) As an example, a battery manufactured by the method described in the above embodiment of the present invention was used. The battery fabricated in this manner is hereinafter referred to as Battery A1 of the invention.

(Examples 2 to 6) The B / Nb ratio was set to 0.04 (1 wt% in mass ratio), 0.12 (3 wt% in mass ratio), and 0.29 (7 wt% in mass ratio), respectively. ,
A battery was fabricated in the same manner as in Example 1, except that the positive electrode active material was fabricated at 0.38 (9 wt% in mass ratio) and 0.47 (11 wt% in mass ratio). The batteries fabricated in this manner are hereinafter referred to as Batteries A2 to A6 of the invention, respectively.

(Comparative Example) A battery was manufactured in the same manner as in Example 1 except that boron oxide was not added at the time of manufacturing the positive electrode active material. The battery fabricated in this manner is hereinafter referred to as Comparative Battery X.

(Experiment) The discharge capacity and internal resistance of the batteries A1 to A6 of the present invention and the comparative battery X were measured. The results are shown in Table 1 and FIG. In addition, since the amount of generated carbon dioxide gas (the amount of generated CO ₂ ) of these batteries was measured, the results are also shown in Table 1 (in Table 1, the relative amount when the amount of generated CO _{2 of} Comparative Battery X was 100). Values represent the amount of CO ₂ generated in the batteries A1 to A6 of the present invention). still,
The discharge capacity was measured by constant current discharge at a current density of 9 A / m ² , and the internal resistance was measured by the AC method (1 kHz).
_{(2) The} amount of generated gas was measured by heating the positive electrode active material and propylene carbonate at 235 ° C., and measuring the generated gas by gas chromatography.

[0027]

[Table 1]

As is clear from Table 1 and FIG. 2, the batteries A1 to A6 of the present invention have a lower internal resistance than the comparative battery X, and in particular, the batteries of the present invention having a B / Nb ratio of 0.12 or more. In A1, A3 to A6, it is recognized that the internal resistance is significantly reduced. Therefore, from the viewpoint of reducing the internal resistance, it is desirable to use a positive electrode active material obtained by mixing niobium oxide and boron oxide and firing the mixture. In particular, B / Nb
It can be seen that it is desirable to use a positive electrode active material obtained by mixing and firing niobium oxide and boron oxide so that the ratio becomes 0.12 or more. In addition, as is clear from Table 1 and FIG. 2, the batteries A1 to A5 of the present invention having a B / Nb ratio of 0.38 or less.
Is smaller than the comparative battery X in the discharge capacity, but B
It can be seen that the battery A6 of the present invention having the / Nb ratio of 0.47 had a larger decrease in the discharge capacity than the comparative battery X. Therefore, from the viewpoint of suppressing a decrease in the discharge capacity, it is understood that it is desirable to use a positive electrode active material obtained by mixing and firing niobium oxide and boron oxide so that the B / Nb ratio becomes 0.38 or less. Furthermore, as is clear from Table 1, the batteries A1 to A6 of the present invention were compared with the comparative battery X,
It is recognized that the amount of generated CO ₂ has been significantly reduced.
Therefore, in terms of reducing the amount of CO ₂ generated,
It can be seen that it is desirable to use a positive electrode active material obtained by mixing and firing niobium oxide and boron oxide.

[0029]

As described above, according to the present invention,
It suppresses the internal resistance of the battery from becoming high and suppresses the reaction between the niobium oxide and the electrolyte even when the battery is exposed to a high temperature, thereby preventing leakage caused by the generation of carbon dioxide gas. It has an excellent effect of preventing liquid and the like.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a battery of the present invention.

FIG. 2 is a graph showing a relationship between a B / Nb ratio and a discharge capacity and an internal resistance.

[Explanation of symbols]

 Reference Signs List 1 positive electrode 2 negative electrode 3 separator 4 positive electrode can (exterior can) 5 negative electrode can (sealing lid) 6 insulating packing

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Nobuhiro Nishiguchi 2-5-1-5, Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Shoichi Inamine 2-chome, Keihanhondori, Moriguchi-shi, Osaka No. 5-5 Sanyo Electric Co., Ltd. (72) Katsuyuki Kida 2-5-5 Sanyo Electric Co., Ltd. (72) Inventor Yoshitaka Minamida Yoshitaka Minamida Keihanhondori, Moriguchi, Osaka 2-5-5 Sanyo Electric Co., Ltd. (72) Inventor Masahiro Imanishi 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term (reference) 5H011 AA17 GG02 HH02 5H029 AJ06 AJ07 AJ15 AK02 AK18 AM03 AM04 AM05 AM07 BJ03 BJ12 CJ02 CJ08 DJ03 EJ12 HJ02 5H050 AA12 AA13 AA20 BA16 BA17 CA02 CA29 CB07 CB12 FA02 GA02 GA10 HA02

Claims (6)

[Claims] 1. A non-aqueous electrolyte battery comprising: a positive electrode using a compound capable of inserting and removing lithium as a positive electrode active material; a negative electrode using a material capable of inserting and removing lithium as a negative electrode active material; and a non-aqueous electrolyte 3. The non-aqueous electrolyte battery according to claim 1, wherein the positive electrode active material contains niobium oxide and boron oxide. 2. The nonaqueous electrolyte battery according to claim 1, wherein the positive electrode active material dissolves the boron oxide and adheres to the surface of the niobium oxide. 3. An atomic ratio of boron to niobium of 0.0
4 or more and 0.38 or less (especially 0.12 or more and 0.38 or less)
3. The nonaqueous electrolyte battery according to claim 1, wherein the addition ratio of the boron oxide to the niobium oxide is regulated such that 4. The battery has an outer can, a sealing lid, and an insulating gasket interposed between the outer can and the sealing lid to seal the battery in addition to the positive and negative electrodes and the non-aqueous electrolyte. 4. The non-aqueous electrolyte battery according to claim 1, wherein said insulating gasket is made of a polymer material having an aromatic ether, aromatic sulfide, or aromatic ester structure in a main chain. 5. A method for producing a non-aqueous electrolyte battery, comprising a step of producing a positive electrode active material by firing a mixture of a boron compound and niobium oxide. 6. The method for producing a non-aqueous electrolyte battery according to claim 5, wherein the boron compound is boron oxide or boric acid.