JP2007220455A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery in which cycle characteristics are not deteriorated and reliability in high temperature storage is high even when the capacity and energy density of the battery are increased. <P>SOLUTION: The nonaqueous electrolyte secondary battery is equipped with an electrode group comprising a positive plate, a negative plate, and a separator, and a nonaqueous electrolyte, and the volume of the nonaqueous electrolyte is made 1.3-1.8 μL per 1 mAh of discharge capacity. In the nonaqueous electrolyte secondary battery comprising the electrode group having the positive plate, the negative plate, and the separator, and the nonaqueous electrolyte, the volume of the electrolyte is made 1.3-1.8 μL per 1 mAh of the discharge capacity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte amount.

  In recent years, electronic devices have become more portable and cordless, and there is an increasing demand for secondary batteries that are small, lightweight, and have high energy density as power sources for driving these devices. Among non-aqueous electrolyte secondary batteries having high voltage and high energy density, expectations for lithium secondary batteries are particularly high. In addition, recent electronic devices are being further enhanced in functionality and power, and there is a demand for further increase in energy density of lithium secondary batteries.

  However, this lithium secondary battery has the following two problems. The first problem is that a part of the non-aqueous electrolyte is decomposed and consumed as the charge / discharge cycle proceeds, so that when the amount of non-aqueous electrolyte in the electrode plate cannot be secured, There was a problem that the cycle characteristics deteriorated due to withering.

  The second problem is that when a lithium secondary battery is exposed to a high temperature atmosphere, the non-aqueous electrolyte is decomposed electrochemically and thermally to gasify. For this reason, there has been a problem that the internal pressure of the battery rises and the battery expands, the explosion-proof safety valve malfunctions, and the electrolyte leaks.

In order to prevent such problems, in short, as a means for preventing charge / discharge cycle deterioration and safety valve malfunction in a high temperature atmosphere, a non-aqueous electrolyte solution in a non-aqueous electrolyte secondary battery with a capacity of 110 mAh / cc or more per unit volume It has been proposed that the amount be 1.8 to 2.4 μL per 1 mAh of discharge capacity of the battery (see, for example, Patent Document 1).
JP 2000-285959 A

  However, in the conventional method described above, the porosity (gap in the electrode plate) is reduced by increasing the density of the positive and negative electrode plates, and it is difficult for a predetermined amount of the non-aqueous electrolyte to penetrate. Therefore, enormous time is required to inject a predetermined amount of non-aqueous electrolyte, and there is a problem in improving productivity. In addition, when the capacity per unit volume becomes 120 mAh / cc or more, the volume occupied by the positive and negative electrode plates in a certain volume in the battery increases, and it is not possible to secure a volume sufficient to soak a predetermined amount of nonaqueous electrolyte. There was also a problem. In addition, when the non-aqueous electrolyte is less than or larger than the predetermined amount, the following problems occur. When the amount of the non-aqueous electrolyte is less than a predetermined amount, the amount of the non-aqueous electrolyte in the electrode plate becomes insufficient with the expansion and contraction of the positive and negative electrode plates due to repeated charge and discharge, and the cycle characteristics are deteriorated. When the amount of the non-aqueous electrolyte is larger than a predetermined amount, when the battery is stored at a high temperature, there is no room in the battery, so that the increase in the battery internal pressure cannot be absorbed and the safety valve malfunctions.

  Therefore, in view of the above-described conventional problems, the present invention provides a non-aqueous electrolyte solution that is excellent in reliability during high-temperature storage without deterioration of cycle characteristics even when the battery is increased in capacity and energy density. The purpose is to provide a secondary battery.

  In order to solve the conventional problems, a non-aqueous electrolyte secondary battery of the present invention includes an electrode group having a positive electrode plate, a negative electrode plate, and a separator, and a non-aqueous electrolyte, and the amount of the non-aqueous electrolyte is a discharge capacity. The amount is 1.3 to 1.8 μL per mAh.

  According to the present invention, it is possible to provide a non-aqueous electrolyte secondary battery having a high capacity and high energy density, and excellent in cycle characteristics and reliability during high-temperature storage.

  The non-aqueous electrolyte secondary battery of the present invention includes an electrode group having a positive electrode plate, a negative electrode plate and a separator, and a non-aqueous electrolyte, and the amount of the non-aqueous electrolyte is 1.3 to 1.8 μL per 1 mAh discharge capacity. It is characterized by doing.

  By doing so, it becomes possible to obtain a non-aqueous electrolyte secondary battery having a high energy density, excellent cycle characteristics, and high reliability during high-temperature storage. When the amount of the non-aqueous electrolyte was less than 1.3 μL per 1 mAh discharge capacity, the amount of the non-aqueous electrolyte in the positive and negative electrode plates was insufficient due to repeated charge and discharge, and the cycle characteristics were deteriorated due to liquid drainage. When the amount of the non-aqueous electrolyte was 1.8 μL or more per 1 mAh discharge capacity, the safety valve malfunctioned during high temperature storage. From the above, the non-aqueous electrolyte is 1.3 to 1.8 μL per 1 mAh of battery discharge capacity, and both cycle characteristics and reliability during high temperature storage can be achieved.

In the nonaqueous electrolyte secondary battery according to a preferred embodiment of the present invention, the positive electrode active material is represented by the general formula Li _x Ni _y M _1-y O ₂ (x: 0.95 ≦ x ≦ 1.10, M is Co, A lithium composite nickel oxide represented by at least one of Mn, Cr, Fe, Mg, Ti and Al, y: 0.3 ≦ y ≦ 0.95) is preferable.

Thus, when lithium composite cobalt oxide (hereinafter abbreviated as LiCoO ₂ ) is used as the positive electrode active material, the capacity per unit volume is about 120 mAh / cc, but the general formula of the positive electrode active material is Li _x Ni _y M _1-y O ₂ (x: 0.95 ≦ x ≦ 1.10, M is one or more of Co, Mn, Cr, Fe, Mg, Ti and Al, y: 0.3 ≦ y By using the lithium composite nickel oxide represented by ≦ 0.95), a non-aqueous electrolyte secondary battery having a high energy density of 130 mAh / cc or more per unit volume can be obtained.

In particular, the positive electrode active material is represented by the general formula Li _x Ni _y M _1-y O ₂ (x: 0.95 ≦ x ≦ 1.10, M is at least one of Co, Mn, Cr, Fe, Mg, Ti and Al). As above, as representatives of lithium composite nickel oxide represented by y: 0.3 ≦ y ≦ 0.95), LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _0.6 Co _0.3 Al _0.1 O ₂ LiNi _0.6 Co _0.3 Ti _0.1 O ₂ , and LiNi _0.5 Co _0.5 O ₂ .

  The non-aqueous electrolyte secondary battery according to a preferred embodiment of the present invention uses a lithium composite nickel oxide as a positive electrode active material, has a structure in which primary particles are aggregated, and the secondary particles are spherical or elliptical spherical. preferable.

  By doing so, the liquid retainability of the non-aqueous electrolyte is improved by the positive electrode plate, and a non-aqueous electrolyte secondary battery that can exhibit excellent cycle characteristics even with a small amount of the non-aqueous electrolyte can be obtained.

In terms of battery discharge capacity, LiCoO ₂ has a capacity of about 120 mAh / cc per unit volume, whereas lithium composite nickel oxide of the general formula Li _x Ni _y M _1-y O ₂ has a capacity of 130 mAh / cc or more per unit volume. The general formula Li _x Ni _y M _1-y O ₂ is a positive electrode active material having a higher capacity and higher energy density. If to produce a positive electrode plate having the same density as LiCoO ₂ using a general formula _{Li x Ni y M 1-y} O 2, the general formula Li _x Ni _y M _1-y representative example of O ₂ is LiNi _1/3 Co Batteries using _1/3 Mn _1/3 O ₂ (circles in FIG. 2) and LiNi _0.6 Co _0.3 Al _0.1 O ₂ (triangles in FIG. 2) are batteries using LiCoO ₂ (squares in FIG. 2). It was found that excellent cycle characteristics were exhibited even when the amount of the non-aqueous electrolyte was small.

The reason why such an effect is obtained is not necessarily limited by the inventor's theory, but the inventor presumes as follows. It is thought that the following explanation can be made from the viewpoint of the reaction active point of the positive electrode active material involved in the battery discharge capacity. That is, when a positive electrode plate having the same density as LiCoO ₂ is produced using the general formula Li _x Ni _y M _1-y O ₂ and the same amount of non-aqueous electrolyte is put, the general formula Li _x Ni _y M _{1- It is considered that yO 2} has more reaction active points of the positive electrode active material that can come into contact with the electrolytic solution, and can maintain the state in which the electrolytic solution is retained even when the positive electrode plate expands and contracts due to charging and discharging of the battery. .

In order to support this, the following is considered. When LiCoO ₂ is used as the positive electrode active material, the positive electrode plate expands and contracts due to charging / discharging of the battery, so that the amount of non-aqueous electrolyte retained in the positive electrode plate is reduced and the cycle characteristics are deteriorated. . However, from the electron microscope (hereinafter abbreviated as SEM) observation photograph of the positive electrode active material LiCoO ₂ shown in FIG. 3A, the surface of LiCoO ₂ is smooth. On the other hand, LiNi _1/3 Co _1/3 Mn _1/3 O ₂ and LiNi _0.6 Co _0.3 Al _0.1 O _2, which are representative examples of the general formula Li _x Ni _y M _1-y O ₂ , have a structure in which primary particles are aggregated. In addition, since the secondary particles are spherical or elliptical (see the SEM observation photographs shown in FIGS. 3B and 3C), even if the positive electrode plate expands and contracts due to charge / discharge of the battery. The positive electrode active material itself is considered to be unlikely to deteriorate in cycle characteristics because of its shape that can easily hold liquid.

  In order to obtain a positive electrode active material whose secondary particles are spherical or elliptical, it is known that spherical or elliptical nickel hydroxide is preferably used as a starting material.

  Embodiments of the present invention will be described below with reference to the drawings.

  In FIG. 1, the longitudinal cross-sectional schematic of the cylindrical lithium secondary battery which is an Example of this invention is shown.

  In FIG. 1, a separator 7 made of polypropylene is interposed as a separator between a positive electrode plate 5, a negative electrode plate 6, and both electrodes, and these are wound in a spiral shape to constitute an electrode plate group 4. The electrode plate group 4 is inserted into a battery case 1 made of a stainless steel plate having a diameter of 13.8 mm and a height of 50 mm. A positive electrode lead 5 a is drawn out from the positive electrode plate 5 and connected to the sealing plate 2 by welding. A negative electrode lead 6 a is drawn out from the negative electrode plate 6 and connected to the bottom of the battery case 1 by welding. The sealing plate 2 is sealed by caulking with the battery case 1 through the insulating packing 3. The insulating rings 8 are provided above and below the electrode plate group 4, respectively.

  Hereinafter, the positive electrode plate 5, the negative electrode plate 6, and the non-aqueous electrolyte will be described.

The positive electrode plate 5 includes 100 parts by weight of a powder of lithium cobalt oxide (hereinafter abbreviated as LiCoO ₂ ) as a positive electrode active material, 5 parts by weight of acetylene black as a conductive material, and polyvinylidene fluoride (hereinafter referred to as PVDF) as a binder. 5 parts by weight and an appropriate amount of an organic solvent of N-methylpyrrolidone (hereinafter abbreviated as NMP) to prepare a paste-like positive electrode mixture. This positive electrode mixture was applied to the surface of an aluminum foil (hereinafter abbreviated as Al) having a thickness of 0.010 mm and dried. After drying, the product is rolled by a roll press and cut into a size of 35 mm in width and 250 mm in length to obtain a positive electrode plate 5.

  The negative electrode plate 6 is obtained by mixing 10 parts by weight of a styrene-based binder as a binder with 100 parts by weight of carbon powder obtained by heat-treating coke, which is a negative electrode active material, and suspending this in an aqueous solution of carboxymethyl cellulose. To prepare a paste-like negative electrode mixture. This negative electrode mixture was applied to the surface of a copper foil having a thickness of 0.015 mm and dried. After drying, it is rolled to a thickness of 0.2 mm by a roll press and cut into a size of 37 mm width and 280 mm length to obtain a negative electrode plate.

The non-aqueous electrolyte was mixed in an equal volume mixed solvent of ethylene carbonate (hereinafter abbreviated as EC) and diethyl carbonate (hereinafter abbreviated as DEC), lithium hexafluorophosphate (hereinafter abbreviated as LiPF ₆ ) as an electrolyte salt. Dissolve at 0 mol / L. A predetermined amount of non-aqueous electrolyte is injected into the electrode plate group 4.

  After injecting the non-aqueous electrolyte, the sealing plate is caulked to the case and sealed. In this manner, a cylindrical lithium secondary battery having a rated capacity of 850 mAh, a size of 14 mm in diameter, and a height of 50 mm, so-called 14500 size is manufactured.

  The amount of non-aqueous electrolyte will be described in detail below.

Example 1
The amount of non-aqueous electrolyte was added at 1.3 μL per mAh.

(Example 2)
A battery was fabricated in the same manner as in Example 1 except that 1.8 μL of nonaqueous electrolyte was added per mAh.

(Comparative Example 1)
A battery was fabricated in the same manner as in Example 1 except that 1.2 μL of nonaqueous electrolyte was added per mAh.

(Comparative Example 2)
A battery was fabricated in the same manner as in Example 1 except that 1.9 μL of nonaqueous electrolyte was added per mAh.

(Example 3)
A battery was prepared in the same manner as in Example 1 except that LiNi _1/3 Co _1/3 Mn _1/3 O ₂ was used as the positive electrode active material.

Example 4
A battery was prepared in the same manner as in Example 2 except that LiNi _1/3 Co _1/3 Mn _1/3 O ₂ was used as the positive electrode active material.

(Comparative Example 3)
A battery was prepared in the same manner as in Comparative Example 1 except that LiNi _1/3 Co _1/3 Mn _1/3 O ₂ was used as the positive electrode active material.

(Comparative Example 4)
A battery was prepared in the same manner as in Comparative Example 2 except that LiNi _1/3 Co _1/3 Mn _1/3 O ₂ was used as the positive electrode active material.

(Example 5)
A battery was prepared in the same manner as in Example 1 except that LiNi _0.6 Co _0.3 Al _0.1 O ₂ was used as the positive electrode active material.

(Example 6)
A battery was prepared in the same manner as in Example 2 except that LiNi _0.6 Co _0.3 Al _0.1 O ₂ was used as the positive electrode active material.

(Comparative Example 5)
A battery was prepared in the same manner as in Comparative Example 1 except that LiNi _0.6 Co _0.3 Al _0.1 O ₂ was used as the positive electrode active material.

(Comparative Example 6)
A battery was prepared in the same manner as in Comparative Example 2, except that LiNi _0.6 Co _0.3 Al _0.1 O ₂ was used as the positive electrode active material.

(Example 7)
A battery was prepared in the same manner as in Example 1 except that LiNi _0.5 Co _0.5 O ₂ was used as the positive electrode active material.

(Example 8)
A battery was prepared in the same manner as in Example 2 except that LiNi _0.5 Co _0.5 O ₂ was used as the positive electrode active material.

(Comparative Example 7)
A battery was prepared in the same manner as in Comparative Example 1 except that LiNi _0.5 Co _0.5 O ₂ was used as the positive electrode active material.

(Comparative Example 8)
A battery was prepared in the same manner as in Comparative Example 2, except that LiNi _0.5 Co _0.5 O ₂ was used as the positive electrode active material.

In addition, for the cylindrical lithium secondary batteries of Examples 1 to 8 and Comparative Examples 1 to 8, charge / discharge cycle characteristic test, safety valve false shut-off occurrence probability test at high temperature storage, non-aqueous electrolyte retention amount test, and positive electrode active SEM observation of the material was performed. These test methods are described below.
<Charge / discharge cycle characteristics test>
At an environmental temperature of 20 ° C., the charge / discharge cycle characteristics were evaluated under the following conditions.

  The charging conditions were a constant current of 850 mA and a battery voltage of 4.2 V. After the battery voltage reached 4.2 V, the battery was charged at a constant voltage of 4.2 V so that the total charging time was 2 hours.

  The discharge conditions were a constant current of 850 mA and the battery was discharged until the discharge start voltage of the battery reached 3.0V.

  These charge and discharge were made into 1 cycle, and 100 cycles were repeated. From the discharge capacity at the first cycle and the discharge capacity at the 100th cycle, the discharge capacity retention ratio was calculated by the following formula.

Discharge capacity retention ratio (%) = capacity at the 100th cycle (mAh) / capacity at the first cycle (mAh) × 100
<Probability test for safety valve false shut-off during high temperature storage>
Each cylindrical lithium secondary battery is charged at an environmental temperature of 20 ° C. with a constant current of 850 mA and a voltage of 4.20 V. After reaching the voltage of 4.20 V, the total charging time is 2 hours. Charging was performed at a constant voltage of 4.20V. Thereafter, the battery was left for 5 hours at an environmental temperature of 100 ° C., and the shutoff rate of the battery safety valve was measured. The test was conducted for 20 lots.
<Non-aqueous electrolyte retention test>
10 g of each positive electrode active material was weighed and immersed in a non-aqueous electrolyte at an environmental temperature of 20 ° C. for 1 minute. The positive electrode active material impregnated with the nonaqueous electrolyte was weighed again, and the amount of nonaqueous electrolyte retained per gram of active material was measured.

Table 1 shows the results of the charge / discharge cycle test, the probability of occurrence of erroneous safety valve shut-off during high-temperature storage, and the amount of nonaqueous electrolyte retained per gram of positive electrode active material.
<SEM observation of positive electrode active material>
An electron microscope (manufactured by Hitachi, model number: S-4500) was used for SEM observation. After the positive electrode active material powder was placed on the sample stage, the sample surface was Os coated to prepare a sample for SEM observation. As SEM observation conditions, observation was performed at an acceleration voltage of 5 kV and an observation magnification of 5000 or 10,000 times.

The SEM observation of the positive electrode active material LiCoO ₂ is shown in FIG. 3A, the SEM observation of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ is shown in FIG. 3B, and LiNi _0.6 Co _0.3 Al _0.1 O _2. The SEM observation of is shown in FIG.

From the results shown in Table 1, in Comparative Example 1, compared with Examples 1 and 2 and Comparative Example 2, the maintenance ratio of the charge / discharge cycle characteristics was lowered. Moreover, when the amount of non-aqueous electrolyte was 1.2 μL per 1 mAh of battery discharge capacity as in Comparative Examples 3, 5, and 7, a decrease in charge / discharge cycle characteristics was observed.

  In Comparative Example 2, 20% of the safety valve was accidentally shut off in the high temperature standing test. As in Comparative Examples 4, 6, and 8, when the amount of non-aqueous electrolyte was 1.9 μL per 1 mAh of battery discharge capacity, the safety valve was erroneously blocked. Therefore, it can be said that the amount of the non-aqueous electrolyte is preferably 1.3 to 1.8 μL per 1 mAh of the battery discharge capacity from the viewpoint of the maintenance rate of the charge / discharge cycle characteristics and the probability of occurrence of the safety valve erroneous shut-off during high temperature storage.

Since the positive electrode active materials LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _0.6 Co _0.3 Al _0.1 O ₂ , and LiNi _0.5 Co _0.5 O ₂ have a large discharge capacity per unit volume, It is desirable as a positive electrode active material for realizing a density energy battery. In the examples, LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _0.6 Co _0.3 Al _0.1 O ₂ , and LiNi _0.5 Co _0.5 O ₂ were used to achieve a battery capacity of 850 mAh. In Examples 3 to 8, the coating weight (electrode plate weight) of the positive electrode active material was reduced. Therefore, Examples 3 to 8 using LiNi _1/3 Co _1/3 Mn _1/3 O ₂ and LiNi _0.6 Co _0.3 Al _0.1 O ₂ as the positive electrode active material are the spaces remaining in the battery (remaining spaces). Became larger. Here, the remaining space means a space obtained by subtracting the volume occupied by the battery constituent material from the volume in the battery. Therefore, when Comparative Examples 2, 4, 6, and 8 in which the amount of the nonaqueous electrolyte is 1.9 μL per 1 mAh of discharge capacity are compared, LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _0.6 than LiCoO ₂ are compared. Co _0.3 Al _0.1 O ₂ and LiNi _0.5 Co _0.5 O _{2 have} a better safety valve false shutoff rate. That is, when LiNi _1/3 Co _1/3 Mn _1/3 O ₂ and LiNi _0.6 Co _0.3 Al _0.1 O ₂ , LiNi _0.5 Co _0.5 O ₂ are used as the positive electrode active material, they are stored at a higher temperature than when LiCoO ₂ is used. It can be said that the reliability of the time can be further increased.

The amount of the non-aqueous electrolyte retained in the positive electrode active material is such that the primary particles are aggregated and the secondary particles are spherical (see the SEM observation photograph in FIG. 3). LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _0.6 Co _0.3 Al _0.1 O ₂ and LiNi _0.5 Co _0.5 O ₂ gave good results. It can be presumed that this is because the aggregate of primary particles has more pores that can hold the non-aqueous electrolyte.

LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _0.6 Co _0.3 Al _0.1 O ₂ , LiNi _0.5 Co _0.5 O ₂ have a good amount of non-aqueous electrolyte solution. When Comparative Examples 1, 3, 5, and 7 with 1.2 μL per discharge capacity were compared, it is considered that the charge / discharge cycle characteristics were improved compared to LiCoO ₂ . Further, in Examples 2, 4, 6, and 8 in which the amount of the non-aqueous electrolyte was 1.8 μL per 1 mAh of discharge capacity, the charge / discharge cycle characteristics were also improved as compared with LiCoO ₂ . From the above, the charge / discharge cycle characteristics are preferably a structure in which primary particles of lithium composite nickel oxide are aggregated, and the secondary particles are preferably spherical or elliptical.

  In this example, the results of evaluation using a cylindrical lithium secondary battery were described. However, the same effect can be obtained even if the battery shape is different, such as a square shape, a coin shape, a button shape, and a laminate shape. .

  In this embodiment, the rated capacity of the cylindrical lithium secondary battery has been described as 850 mAh, but a battery with a capacity other than 850 mAh may be used.

In this example, LiCoO ₂ and LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _0.6 Co _0.3 Al _0.1 O ₂ , and LiNi _0.5 Co _0.5 O ₂ were described as the positive electrode active material. It is not limited to substances.

  In this example, coke was used as the negative electrode material that reversibly reacts with lithium. However, carbon materials such as graphite and amorphous materials or mixtures thereof, metal oxides such as silicide or mixtures thereof were used. May be.

  In this example, evaluation was performed using a polypropylene separator as a separator, but an organic microporous film such as polyethylene or an inorganic microporous film may be used. For example, the inorganic microporous film is a film in which an inorganic filler such as alumina or silica and an organic binder for binding the inorganic filler are mixed as a binder. The inorganic microporous film may be interposed between the positive electrode and the negative electrode. As a method of interposing between these electrode plates, an inorganic microporous film may be formed on the surface of the positive electrode, or an inorganic microporous film may be formed on the surface of the negative electrode. Moreover, you may use both an inorganic microporous film and an organic microporous film.

Furthermore, in this example, LiPF ₆ was used as the electrolyte salt, but other lithium salts may be, for example, lithium perchlorate (LiClO ₄ ), lithium tetrafluoroborate (LiBF ₄ ), or the like. Moreover, although the density | concentration of electrolyte salt was 1.0 mol / L, you may use a salt density | concentration of 0.5-2.0 mol / L. In addition, a 1: 1 (volume ratio) mixed solvent of EC and DEC was used as the non-aqueous electrolyte, but as other non-aqueous solvents, for example, cyclic esters such as propylene carbonate (PC), tetrahydrofuran (THF) and the like Nonaqueous solvents such as cyclic ethers, chain ethers such as dimethoxyethane (DME), chain esters such as methyl propionate (MP), and these multicomponent mixed solvents may also be used.

  Moreover, although the lithium secondary battery has been described as the nonaqueous electrolyte secondary battery, the same effect can be obtained in a nonaqueous electrolyte secondary battery such as a magnesium secondary battery other than the lithium secondary battery. is there.

  The non-aqueous electrolyte secondary battery according to the present invention is useful as a power source for portable electric equipment that requires high capacity and high reliability, and can also be used as a driving power source for automobiles and housing equipment such as elevators. Useful.

Schematic cross-sectional view of a cylindrical lithium battery in an embodiment of the present invention Diagram of charge / discharge cycle test results of Example 1, Example 3, and Example 5 (A) SEM observation photograph of positive electrode active material LiCoO ₂ , (b) SEM observation photograph of positive electrode active material LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , (c) Positive electrode active material LiNi _0.6 Co _0.3 Al _0.1 SEM observation photograph of O ₂

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery case 2 Sealing plate 3 Insulation packing 4 Electrode plate group 5 Positive electrode plate 5a Positive electrode lead 6 Negative electrode plate 6a Negative electrode lead 7 Separator 8 Insulation ring

Claims (3)

  In a non-aqueous electrolyte secondary battery including a positive electrode plate, a negative electrode plate, and a separator, and a non-aqueous electrolyte solution, the amount of the non-aqueous electrolyte solution is 1.3 to 1.8 μL per 1 mAh discharge capacity. Non-aqueous electrolyte secondary battery. The positive electrode active material of the positive electrode plate has the general formula Li _x Ni _y M _1-y O ₂ (x: 0.95 ≦ x ≦ 1.10, M is Co, Mn, Cr, Fe, Mg, Ti and Al). The nonaqueous electrolyte secondary battery according to claim 1, wherein the lithium composite nickel oxide is represented by at least one or more of y: 0.3 ≦ y ≦ 0.95).   The non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium composite nickel oxide has a structure in which primary particles are aggregated, and the secondary particles are spherical or elliptical.