JPH1069924A - Non-aqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure high capacity of a battery by restricting a discharge capacity per unit reaction area of an electrode. SOLUTION: A negative electrode having a carbon material as active substance and a positive electrode having a lithium composite oxide as active material are laminated in three or more layers and is stored in a battery case. An electrode thickness and the number of laminates are determined so that the discharge capacity per unit reaction area of the electrode laminate is 6 to 100mAh/cm<2> . Thereby, high capacity of a battery can be ensured. Restriction of this discharge capacity ensures high capacity during light load, and good characteristics can be obtained even during practical load of about 5 hours %. When the discharge capacity is more than 100mAh/cm<2> , the number of laminates is reduced, and satisfactory characteristics cannot be obtained in an ordinary rectangular or cylindrical secondary battery. When the discharge capacity is less than 6mAh/cm<2> , the number of laminates is increased, and the capacity is similar to that of a conventional battery. Consequently, the discharge capacity is restricted in this range and preferably 6 to 30mAh/cm<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a nonaqueous electrolyte secondary battery using a carbonaceous material as a negative electrode active material.

[0002]

2. Description of the Related Art In recent years, with the spread of portable devices such as video cameras and radio cassette tape recorders, demand for secondary batteries which can be used repeatedly instead of disposable primary batteries has been increasing.

Most of the secondary batteries currently used are nickel cadmium batteries using an alkaline electrolyte. However, the voltage of a nickel cadmium battery is as low as about 1.2 V, and it is difficult to improve the energy density of the battery. The self-discharge rate at room temperature is as high as 20% or more in one month.

On the other hand, non-aqueous electrolyte secondary batteries using a non-aqueous solvent for the electrolyte and a light metal such as lithium for the negative electrode have been studied. This nonaqueous electrolyte secondary battery has a high voltage of 3 V or more, a high energy density, and a low self-discharge rate. However, in such a secondary battery, metallic lithium or the like used for the negative electrode grows in a dendrite shape by repeated charge and discharge and comes into contact with the positive electrode, and as a result, a short circuit occurs inside the battery. Therefore, it has a drawback that it has a short life, and its practical use is difficult.

For this reason, a non-aqueous electrolyte secondary battery in which lithium or the like is alloyed with another metal and this alloy is used for a negative electrode has been studied. However, such a secondary battery has a drawback that the alloy becomes fine particles due to repeated charging and discharging, and also has a short service life.

Accordingly, for example, Japanese Patent Application Laid-Open No. 62-90863
As disclosed in Japanese Patent Application Laid-Open Publication No. H10-209, a non-aqueous electrolyte secondary battery using a carbonaceous material such as coke as a negative electrode active material has been proposed. Such a secondary battery utilizes the doping / dedoping of lithium into the carbon layer or the fine pores of the negative electrode for the battery reaction, and the negative electrode does not have the above-mentioned disadvantages, and has safety, Excellent cycle life characteristics. The positive electrode active material of such a secondary battery includes Li _x MO ₂ (M represents one or more transition metals, as proposed by the present inventors in Japanese Patent Application Laid-Open No. 63-135099, 0.05 <X <1.10.) Can be used.

[0007]

However, a non-aqueous electrolyte secondary battery using a carbonaceous material as a negative electrode active material,
Compared to a non-aqueous electrolyte secondary battery using metallic lithium or the like as a negative electrode active material, it has excellent cycle life and safety, but is inferior in energy density.

[0008] One of the causes is the use of a binder for binding the powders of the active material to each other.
That is, the carbonaceous material is used in the form of a carbon powder body which is obtained by firing pitch or the like and pulverizing the carbonaceous material or recalcining after pulverizing. Then, a binder such as rubber or the like, a dispersant, etc. is added to the powder to form a slurry, and then, the mixture slurry is applied to a current collector or molded or formed into a pellet to prepare a negative electrode. It is common to do. Therefore, the electrode configuration is composed of three points: a carbonaceous material, a binder, and a current collector, and the binder is usually added at about 3 to 20%. The amount of the active material (filling density) per electrode is limited by the amount of the binder added, and there is a limit in increasing the capacity of the battery.

Accordingly, the present invention has been proposed to solve the above-described problems, and has as its object to provide a high-capacity non-aqueous electrolyte secondary battery.

[0010]

The inventors of the present invention have made intensive studies, and as a result, regulated the discharge capacity per unit reaction area of the electrode laminate, and selected the number and thickness of the electrode layers to meet the regulation. This has led to the discovery of a technology that can provide a high capacity non-aqueous electrolyte secondary battery.

The nonaqueous electrolyte secondary battery according to the present invention is formed by stacking three or more layers including a negative electrode using a carbon material as a negative electrode active material and a positive electrode using a lithium composite oxide as a positive electrode active material. Characterized in that the electrode laminate has a discharge capacity per unit reaction area of 6 to 100 mAh / cm ² .

The discharge capacity per unit reaction area is 6 to 100 mAh / discharge capacity at 0.1 C or less.
cm ² .

In the nonaqueous electrolyte secondary battery according to the present invention, the discharge capacity per unit reaction area of the electrode is 6 to 100.
By determining the thickness of the electrode and the number of laminated layers so as to be mAh / cm ² , the capacity of the battery can be increased.

The discharge capacity per unit reaction area of the electrode is 1
When it exceeds 00 mAh / cm ² , the number of stacked layers decreases, and it can be used as a backup battery used at 0.1 C or less. However, in a normal form of a rectangular secondary battery or a cylindrical secondary battery, , It is difficult to obtain satisfactory characteristics.

On the other hand, if the discharge capacity per unit reaction area of the electrode is less than 6 mAh / cm ² , the number of stacked layers increases and the capacity becomes similar to that of a conventional battery.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the non-aqueous electrolyte secondary battery according to the present invention will be described below.

The nonaqueous electrolyte secondary battery according to the present invention is formed by stacking three or more layers including a negative electrode using a carbon material as a negative electrode active material and a positive electrode using a lithium composite oxide as a positive electrode active material. The stacked electrode body is housed in a battery container. And especially in this battery, the discharge capacity per unit reaction area of the electrode laminate is 6 to 100 mAh / c.
It is regulated in m ^2.

Here, the discharge capacity per unit area is:
The value is divided by the effective reaction area (positive electrode reaction area) based on the discharge capacity at 0.1 C or less.

In the non-aqueous electrolyte secondary battery according to the present invention, the thickness of the electrode and the number of layers are determined so that the discharge capacity per unit reaction area of the electrode laminate thus obtained is 6 to 100 mAh / cm ^2. Is determined.

In the electrode laminate, when the same material is used,
As the electrode thickness increases and the number of stacked layers decreases, the discharge capacity per unit reaction area increases. Conversely, the discharge capacity per unit reaction area decreases as the electrode thickness decreases and the number of stacked layers increases.

As described above, by selecting the electrode thickness and the number of laminated electrodes based on the discharge capacity per unit reaction area, the capacity of the battery can be increased. Further, when the discharge capacity per unit reaction area is regulated, not only high capacity under light load but also good characteristics can be obtained under practical load of about 5 hours rate.

The discharge capacity per unit reaction area of the electrode is 1
If it exceeds 00 mAh / cm ² , the number of stacked layers will be small, and it can be used as a backup battery used at 0.1 C or less. In a battery, it is difficult to obtain satisfactory characteristics. If the discharge capacity per unit reaction area of the electrode is less than 6 mAh / cm ² , the number of stacked layers increases and the capacity becomes similar to that of a conventional battery.

Therefore, the discharge capacity per unit reaction area of the electrode is preferably 6 to 100 mAh / cm ² ,
-30 mAh / cm ² is more preferable.

In the present invention, the discharge capacity per unit reaction area of the electrode laminate is regulated as described above. This discharge capacity is determined by the thickness of the active material of each electrode constituting the electrode laminate and the filling of the active material. Controlled by density. Therefore, it is desirable to select the configuration of each electrode in consideration of this.

As the negative electrode and the positive electrode constituting the electrode laminate, the following are specifically used.

First, as the negative electrode, a coating type one prepared by applying a negative electrode mixture slurry composed of a carbonaceous material serving as an active material, a binder and a dispersant to a current collector, drying and molding is used. Can be

Alternatively, it may be a molding type produced by adding a binder to a carbonaceous material, granulating the granulated material, and molding the granulated material together with a mesh-shaped current collector. As a granulation method, considering moldability, etc.,
The spray drying method, in which the molten material is atomized by a nozzle and heated, is optimal.

Further, a composite sintered body obtained by sintering a material which is carbonized by sintering together with a mesh-like current collector can be used. In particular, since the composite sintered body does not include the binder, the packing density of the active material can be increased, which is advantageous for increasing the capacity of the battery.

As the carbonaceous material used for the composite sintered body, petroleum pitch, binder pitch, polymer resin or the like is heat-treated to be mesophase pitch, mesophase pitch is partially oxidized, and mesophase pitch is partially A carbonized material, a completely carbonized mesophase pitch, or a material having a sintering property such as green coke that is not completely carbonized can be used.

Carbonized carbon, pyrolytic carbons, cokes (petroleum coke, pitch coke, etc.), carbon black (acetylene black, etc.)
Glassy carbon, fired organic polymer material (fired organic polymer material in an inert gas stream or vacuum at an appropriate temperature of 500 ° C. or more), a pitch containing carbon fibers and the above resin component A resin having a high particle size and a high sintering property, for example, a furan resin, divinylbenzene, polyvinylidene fluoride, polyvinylidene chloride, etc., is subjected to a baking treatment, and a resin whose particle size after pulverization is adjusted can be used.

On the other hand, the positive electrode is also formed by applying a positive electrode mixture slurry comprising a lithium composite oxide as an active material, a binder, a conductive agent and a dispersant to a current collector, drying and molding the same. And a molding type produced by adding a binder to a lithium composite oxide and granulating the granulated body together with a mesh-shaped current collector, and further by sintering. A molded body in which the positive electrode active material is held by a mesh-like current collector is used.

The lithium composite oxide is represented by Li _x MO _y (where M represents one or more kinds of transition metals, and x and y each represent a composition ratio of Li and O). Include LiCoO ₂ , LiNiO ₂ , Li _x Ni _y Co _(1-y)
O ₂ (however, 0.05 ≦ x ≦ 1.10, 0 <y <1), and at least one of Co, Ni, and Fe is used as the transition metal M, and 0.05 ≦ x ≦ 1 10 is preferred.

The above-mentioned lithium composite oxide is obtained by mixing carbonates such as lithium, cobalt, nickel and the like in accordance with the composition, and calcining the mixture in a temperature range of 600 to 1000 ° C. in an atmosphere containing oxygen. The starting materials are not limited to carbonates, but can be synthesized from hydroxides and oxides.

As the electrolytic solution, a solution obtained by dissolving an electrolyte in an organic solvent is used, and any of those conventionally known can be used. Examples of the organic solvent include esters such as propylene carbonate, ethylene carbonate, and γ-butyrolactone, ethers such as diethyl ether, tetrahydrofuran, substituted tetrahydrofuran, dioxolan, pyran and derivatives thereof, dimethoxyethane, diethoxyethane, and the like. -Trisubstitution such as methyl-2-oxazolidinone-
Examples thereof include 2-oxazolidinones, sulfolane, methylsulfolane, acetonitrile, propionitrile, and the like, and these are used alone or as a mixture of two or more.

As the electrolyte, lithium perchlorate, lithium borofluoride, lithium phosphofluoride, lithium aluminate, lithium halide, lithium trifluoromethanesulfonate and the like can be used.

[0036]

EXAMPLE A non-aqueous electrolyte secondary battery to which the present invention was applied was fabricated into a rectangular secondary battery as shown in FIG. 1 and its characteristics were evaluated. In FIG. 1, the number of stacked positive electrodes and negative electrodes is different from each of Examples and Comparative Examples.

Example 1 First, the negative electrode 1 was manufactured as follows.

Low-expansion mesophase carbon powder 250 having a fixed carbon of 88.5% and a total expansion of 0% (by a dilatometer used for a thermal expansion test of coal).
The mesh-under product was fired in an oxidizing atmosphere (here, in air) at 800 ° C. for 1 hour to obtain a powder having an average particle size of 20 μm. This is designated as carbonaceous material A.

A low-expansion mesophase carbon powder 250 having a fixed carbon of 88.5% and a total expansion of 0% (by a dilatometer used for a thermal expansion test of coal).
The mesh-under product is baked at 800 ° C. for 1 hour in an oxidizing atmosphere (here, in air), and then the oxidizing atmosphere is changed to an inert gas (nitrogen), and 900 ° C. in an inert gas.
For 3 hours to obtain a coke-like product, which was pulverized to obtain a powder having an average particle size of 20 μm. This is designated as carbonaceous material B.

Next, the carbonaceous materials A and B were mixed at 70:30, and polyvinyl alcohol (molecular weight) was added as a binder, and water was added as a solvent and kneaded. Thereafter, granulation and particle size adjustment were performed using a mesh of 250 microns or less and 150 microns or more.

Then, the granulated product is pressed together with a copper mesh serving as a negative electrode current collector to form a square shape, and the mesh-integrated electrode is fired in an inert gas at 1000 ° C. for 3 hours. A negative electrode (composite sintered body) 1 was obtained. The negative electrode active material layer had a volume density of 1.25 g / ml and a true specific gravity of 1.75 g / ml. The thickness of the negative electrode 1 is set to 0.18 mm for the outermost two sheets,
0.36 mm.

Next, the positive electrode 2 was produced as follows.

91 parts by weight of LiCoO ₂ as a positive electrode active material, 3 parts by weight of Ketjen black as a conductive agent,
2.5 parts by weight of polyvinylidene fluoride was mixed as a binder, and dimethylformamide was added as a dispersant to this to prepare a slurry. This was dried with hot air at 150 ° C. using a spray dryer for organic solvent (manufactured by Sakamoto Giken Co., Ltd.) to produce a nearly spherical powder-like granulated product having an average particle size of about 100 μm. The granulated product was formed into a square shape together with an aluminum mesh serving as a positive electrode current collector, and a positive electrode 2 was obtained. The volume density of this positive electrode active material layer is
It was 3.1 g / ml. The thickness of the positive electrode 2 is 0.36 m
m.

These negative electrodes 1 were 41.5 × 32.3 m
m and the positive electrode 2 were punched into a strip shape of 39.5 × 31.0 mm. Then, the negative electrode 1 and the positive electrode 2 and 30
A separator 3 made of a microporous polyethylene film having a thickness of μm was sequentially laminated, eight negative electrodes 1 and seven positive electrodes 2 were used, and a total of 15 electrodes were laminated via 17 separators 3. Lastly, the end portion was fixed with an adhesive tape 10 having a width of 40 mm to produce an electrode laminate.

Next, the insulating plate 5 is placed on the nickel-plated square battery can 4, and the spring plate 6 and the electrode pressing agent 1 are placed.
1 together with the electrode laminate. And the negative electrode 1
One end of a negative electrode lead 7 made of nickel was crimped to the negative electrode 1 and the other end was welded to the battery can 4 in order to collect current. In order to collect the current of the positive electrode 2, a positive electrode lead 8 made of aluminum is used.
Was attached to the positive electrode 2 and the other end was laser-welded to the positive electrode terminal 9. The positive electrode terminal 9 interrupts current according to the internal pressure of the battery, and has a built-in safety device having a cleavage valve.

The battery can 4 contains 50% by volume of propylene carbonate and 50% by volume of diethyl carbonate.
An electrolyte solution in which LiPF ₆ was dissolved at 1 mol / l in a mixed solvent with was added. The positive electrode terminal 9 was welded with a laser to produce a rectangular secondary battery having a thickness of 8 mm, a height of 48 mm, and a width of 34 mm.

Examples 2 to 6 Rectangular secondary batteries were produced in the same manner as in Example 1 except that the thickness of the electrodes and the number of layers were changed as shown in Table 1. These prismatic secondary batteries are referred to as Examples 2 to 6.

Table 1 summarizes the thickness and the number of laminated electrodes of Examples 1 to 6 in which a composite sintered body was used for the negative electrode and a molded body made of a granulated body was used for the positive electrode.

[0049]

[Table 1]

Example 7 First, the negative electrode 1 was prepared as follows.

A petroleum pitch is used as a starting material, 10 to 20% by weight of a functional group containing oxygen is introduced therein (oxygen crosslinking), and calcined at a temperature of 1000 ° C. in an inert gas stream.
A carbonaceous material having properties similar to glassy carbon was obtained. As a result of X-ray diffraction measurement of this carbonaceous material, the (002) plane spacing was 3.76 angstroms, and the true specific gravity was 1.58 g / cm ^{3 as} measured by a pycnometer. . This carbonaceous material was pulverized to obtain a carbonaceous material powder having an average particle size of 10 μm.

The carbonaceous material thus obtained was used as a negative electrode active material, and 90 parts by weight thereof and 10 parts by weight of polyvinylidene fluoride as a binder were mixed to prepare a negative electrode mixture. Next, this negative electrode mixture was dispersed in N-methylpyrrolidone as a solvent to make the negative electrode mixture into a slurry.

Then, the slurry-like negative electrode mixture was applied to both sides of a strip-shaped copper foil having a thickness of 0.01 mm serving as a negative electrode current collector, dried, and compression-molded with a roller press to form a strip-shaped negative electrode (coating material). Mold electrode) 1 was produced. The thickness of the negative electrode 1 is 0.18 mm for the outermost two sheets, and 0.36 mm for the normal one.
mm. At this time, the volume density excluding the negative electrode current collector is:
It was 1.0 g / ml.

Next, the positive electrode 2 was produced as follows.

Lithium carbonate and cobalt carbonate are used in a molar ratio of L
i: Co = 1: 1 was mixed and calcined in air for 5 hours. As a result of X-ray diffraction measurement of this material, the result was in good agreement with LiCoO _{2 of} the JCPDS card. Then, it was pulverized using an automatic mortar to obtain LiCoO ₂ .

The LiCoO ₂ thus obtained was used as a positive electrode active material, and 91 parts by weight thereof, 6 parts by weight of graphite as a conductive agent, and 3 parts by weight of polyvinylidene fluoride as a binder were mixed. Adjust the mixture and mix it with N-
It was dispersed in methylpyrrolidone to make a slurry. The slurry-like positive electrode mixture was applied to both surfaces of a 0.02 mm-thick aluminum foil as a positive electrode current collector, and the thickness of the positive electrode 2 was 0.36 mm. At this time, the volume density excluding the current collector was 3.1 g / ml.

As described above, an electrode having the same dimensions as in Example 1 was manufactured except that the configuration of the positive electrode active material layer was changed to a coating type, and a square secondary battery was manufactured.

Examples 8 to 11 Square secondary batteries were manufactured in the same manner as in Experimental Example 7, except that the thickness of the electrodes and the number of layers were changed as shown in Table 2.
These prismatic secondary batteries are referred to as Examples 8 to 11.

Table 2 summarizes the electrode thicknesses and the number of laminated electrodes of Examples 7 to 11 in which coating electrodes were used for the negative electrode and the positive electrode.

[0060]

[Table 2]

Comparative Example 1 The thickness of the negative electrode was 0.17 mm, and the thickness of the positive electrode was 0.18 mm.
And the total number of layers was 29 (shown in Table 1)
Except for the above, a prismatic secondary battery was manufactured in the same configuration as in Experimental Example 1.

Comparative Example 2 The thickness of the negative electrode was 2.54 mm, and the thickness of the positive electrode was 2.54 mm
A prismatic secondary battery was manufactured in the same configuration as in Experimental Example 1 except that the number of stacked layers was changed to two (shown in Table 1).

Evaluation of Characteristics The rectangular secondary batteries of the above Examples and Comparative Examples were charged at a constant current of 400 mA and a final voltage of 4.2 V, and then discharged at a current of 200 mA (discharged at 0.2 C). ,
At a discharge current of 50 mA (discharge at 0.05 C), charge / discharge was performed by performing constant current discharge up to a final voltage of 2.5 V, and a discharge capacity was obtained. Examples 1 to 4 using a sintered body electrode
The results for the prismatic secondary batteries of Example 6 and Comparative Examples 1 and 2 are shown in Table 3 and FIG. Table 4 and FIG. 3 show the results of the square secondary batteries of Examples 7 to 11 using the coating type electrodes.

[0064]

[Table 3]

[0065]

[Table 4]

From these results, it can be seen that the discharge capacity per unit reaction area of the electrode is 6 to 100 mA at a discharge of 0.1 C or less.
It can be seen that the square secondary batteries of Examples 1 to 11 with h / cm ² have a better discharge capacity than the square secondary batteries of Comparative Example. As described above, by regulating the discharge capacity per unit reaction area of the electrode, that is, the thickness and the number of stacked electrodes, the energy density can be improved and a high-capacity battery can be manufactured. Further, not only high capacity under light load but also good characteristics can be exhibited under practical load of about 5 hours rate. In particular, when the discharge capacity per unit reaction area is 6 to 30 mAh / cm ² , the discharge capacity is greatly improved.

Further, as can be seen from Table 3 and FIG. 2, in Examples 1 to 6, there was no decrease in capacity even when the reaction area was reduced as compared with Examples 7 to 11, and the load characteristics were small. Has been improved. This is because, in Examples 7 to 11, a coated electrode is used, whereas in Examples 1 to 6, a composite sintered body is used as a negative electrode active material and a granulated product is used as a positive electrode active material. This is because a molded body is used. That is, since the electrodes made of the sintered body and the molded body do not contain the binder, the packing density of the active material is high, which is advantageous for increasing the capacity of the battery.

As can be seen from the results shown in Table 4 and FIG. 3, in Examples 7 to 11 using the coating type electrode, compared to Examples 1 to 6 using the sintered strip electrode, As described above, although the characteristics are slightly inferior, the filling property is improved and the discharge capacity of the battery is improved by applying a thicker coating than a conventional thin coating film.

When the discharge capacity per unit reaction area of the electrode is less than 6 mAh / cm ² , that is, when the electrode thickness is small and the number of stacked layers is large, as in the prismatic secondary battery of Comparative Example 1, And the effect is small. Further, when the discharge capacity per unit reaction area of the electrode exceeds 100 mAh / cm ^2, as in the prismatic secondary battery of Comparative Example 2, the number of stacked batteries decreases, and the prismatic battery in a normal form and the cylindrical battery Cannot provide satisfactory characteristics.

As described above, in this embodiment, by regulating the discharge capacity per reaction area of the electrode, the thickness and the number of stacked electrodes can be regulated, and a high-capacity nonaqueous electrolyte secondary battery can be manufactured. Thus, an optimal battery design can be performed.

In the present embodiment, the present invention has been described by taking a rectangular battery as an example.
A similar effect can be obtained in a battery using an electrode laminate including at least two layers of electrodes.

[0072]

As is apparent from the above description, in the non-aqueous electrolyte secondary battery according to the present invention, the battery capacity is increased by regulating the discharge capacity per unit reaction area of the electrode. This makes it possible to perform an optimal design for manufacturing a high-capacity battery.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a prismatic secondary battery to which the present invention is applied.

FIG. 2 is a characteristic diagram showing a relationship between a discharge capacity per unit reaction area of the sintered body electrode of the present embodiment and a discharge capacity.

FIG. 3 is a characteristic diagram showing a relationship between a discharge capacity per unit reaction area of the coating type electrode of the present embodiment and a discharge capacity.

[Explanation of symbols]

1 negative electrode, 2 positive electrode, 3 separator, 4 battery can, 5
Insulation plate, 6 spring plate, 7 negative electrode lead, 8 positive electrode lead, 9 positive electrode terminal, 10 tape, 11 electrode compress

Continued on the front page (72) Inventor Norio Mamida 1-1-1 Shimosugishita, Takakura, Hiwada-cho, Koriyama-shi, Fukushima Prefecture Sony Energy Tech Co., Ltd.

Claims (5)

[Claims] 1. A non-aqueous electrolyte having an electrode laminate in which three or more layers are formed by combining a negative electrode using a carbon material as a negative electrode active material and a positive electrode using a lithium composite oxide as a positive electrode active material. In the secondary battery, the discharge capacity per unit reaction area of the electrode laminate is 6 to 10.
A non-aqueous electrolyte secondary battery having a current of 0 mAh / cm ² . 2. The discharge capacity per unit reaction area is as follows:
The nonaqueous electrolyte battery according to claim 1, wherein the discharge in 0.1C below a 6~100mAh / cm ^2. 3. The non-aqueous electrolyte secondary battery according to claim 1, wherein the negative electrode is a composite sintered body obtained by integrally molding a carbonaceous sintered body with a metal mesh. 4. The non-aqueous electrolyte secondary battery according to claim 1, wherein the positive electrode comprises a molded body obtained by integrally molding a granulated lithium composite oxide with a metal mesh. 5. The non-aqueous electrolyte secondary battery according to claim 1, wherein the electrode has a discharge capacity per unit reaction area of 6 to 30 mAh / cm ² .