JP2001176499A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase output power and improve high rate discharge characteristics. SOLUTION: Output power is increased by decreasing the application amount of an active material, instead of increasing the application amount of the active material for a greater density of capacity. Lithium manganate is used as a positive active material, and the weight of the positive electrode active material mixture applied on the single side of a collector is set at 0.8 g/100 cm2 or larger and 1.3 g/100 cm2 or less. Furthermore, hard carbon is used as the negative electrode active material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-aqueous electrolyte secondary battery suitable for applications requiring high output.

[0002]

2. Description of the Related Art Since a lithium secondary battery is a battery that is lightweight and has a high capacity density, its demand is increasing as a battery for portable equipment such as a cellular phone and a personal computer. Also, utilizing its high capacity density, development as batteries for electric vehicles has been actively pursued. Such a lithium secondary battery has a structure in which a power generation element in which a positive electrode formed by applying an active material mixture on a current collector such as a metal foil and a negative electrode is wound through a separator is enclosed in a battery container. It is usually manufactured by applying as much active material mixture as possible on a fixed current collector area in order to increase the capacity density as much as possible.

[0003]

In recent years, a hybrid electric vehicle using a motor and an engine has attracted attention, and lithium secondary batteries for this purpose have been actively developed. I have. However, at present, it is extremely difficult to put a lithium secondary battery into practical use as a battery for a hybrid electric vehicle. This is because batteries for hybrid electric vehicles have the high capacity density required for lithium secondary batteries in previous applications,
In particular, because it is required to have a high output density, in a lithium secondary battery using a non-aqueous electrolyte having essentially small electrical conductivity, sufficient high-rate discharge characteristics and large output could not be obtained. It is. An object of the present invention is to solve such a problem and to provide a nonaqueous electrolyte secondary battery having excellent high-rate discharge characteristics and output characteristics.

[0004]

Means for Solving the Problems A lithium secondary battery is characterized by having a high capacity density.
Until now, development has been pursued with the aim of forming as much active material as possible on the current collector. For this reason,
In order to obtain a large output, a method of increasing the electrode thickness to increase the battery capacity and reducing the load applied to the active material per unit weight has been adopted. However, the present inventors have found that by reducing the amount of active material formed on the current collector per unit area, the capacity density is reduced, but the output density is increased and the high-rate discharge characteristics are improved. The present invention was found to be possible.

That is, in the present invention, lithium manganate is used as a positive electrode active material, and a coating weight of a positive electrode active material mixture containing the positive electrode active material on one surface of the current collector is 0.8 g / 100 c.
A non-aqueous electrolyte secondary battery characterized by having a m ^{2 of not} less than 1.3 g / 100 cm ² or less. In particular, the coating weight is 1.1 g / 100 cm ² or more and 1.3 g / 10
It is good to be 0 cm ² or less. This is because the coating weight of the negative electrode can be reduced and the capacity density of the battery can be increased while maintaining good coatability of the negative electrode.

[0006]

DETAILED DESCRIPTION OF THE INVENTION For example, a battery of the present invention comprises a positive electrode using lithium manganate as a positive electrode active material, an isolator, a negative electrode using a carbon material capable of absorbing and releasing lithium ions as a negative electrode active material, and a non-aqueous electrolyte. A non-aqueous electrolyte battery.

[0007] The lithium manganate in the present invention comprises
The case structure is represented by LixMnOy.
And specifically, LiMnO_Two, Li_TwoMnO_Three, LiM
n_TwoO _Four, LiMn_TwoO_ThreeEtc.
LiMn_TwoO_Four, LiMn _TwoO_ThreeIs represented by
preferable. In these basic skeleton structures,
When substituting a part, a small amount other than the alkali metal element
It is better to substitute at least one kind of element, for example, Co,
Transition metal elements such as Ni, V, Fe, Ti, Cr, and Cu;
Alkaline earth metal elements such as Mg and Ca, Al, In, G
It is replaced by elements such as a, B, and Si. Preferably,
Al, Mg, Cr, and B are preferably substituted.
In the case of the present invention, since the life characteristics can be improved,
It is better to use the changed one.

The positive electrode may contain other active materials in addition to the above-mentioned lithium manganate as a positive electrode active material, or may be constituted by adding an additive such as a transition metal compound. In the present invention, lithium manganate is preferably used as a main component. When adding a transition metal compound as an additive, it is preferable to add about 0.005 to 0.03 with respect to 1 of Mn, and preferably to add a compound of Co and Ni. good.

In the present invention, the positive electrode active material mixture means a mixture of a positive electrode active material, a conductive additive, and a binder in an appropriate ratio. When adjusting this mixture, the average diameter of the secondary particles of the positive electrode active material is preferably 15 μm or less from the viewpoint of coatability such as minimizing the roughness of the coated surface of the electrode plate.

As the conductive agent, carbon compounds such as natural graphite, artificial graphite, channel black, acetylene black, Ketjen black, furnace black, and other carbon blacks, and carbon fibers can be used.
As the binder, polyvinylidene fluoride, polyimide resin, PTFE, styrene butadiene rubber, fluoro rubber,
Or the like, which is difficult to dissolve in the electrolytic solution.
And when this mixture is used as a paste, for example,
The composition of the coating solution is such that 1 to 10 parts by weight of a conductive agent, 2 to 20 parts by weight of a binder, and 3
0 to 300 parts by weight.

Examples of the current collector include metal foils such as aluminum, copper, nickel, and stainless steel; conductive films such as inorganic oxides, organic polymer materials, and carbon; and metal-deposited films (for example, polyethylene terephthalate as a base film). , Polyimide, polyphenylene sulfide,
Examples of the metal to be deposited include gold, copper, and aluminum. ) Can be used. In addition, the form of such a conductive substrate can be various forms such as a continuous sheet, a perforated sheet, a mesh sheet, and the like, and particularly, a continuous sheet is preferable. Note that the active material is preferably applied to such a current collector on both surfaces.

The negative electrode is not particularly limited with respect to its coating weight, and an amount of the negative electrode material capable of accepting the total charge electricity of the positive electrode may be disposed on the facing surface of the positive electrode. Similarly, when formed on a current collector and using a carbon material as a negative electrode active material, 0.25 g / 10
It can be set to 0 cm ² or more and 0.5 g / 100 cm ² or less. In this case, the average diameter of the secondary particles of the negative electrode active material is preferably 15 μm or less from the viewpoint of coatability such as minimizing the roughness of the coated surface.

The negative electrode active material used in the present invention includes:
Carbon materials are preferred. Carbon materials are roughly divided into graphite materials with a uniform crystal structure and non-graphite materials with a disordered crystal structure.The former includes natural graphite and artificial graphite, and the latter has a disordered crystal structure. Yes, but 2000-3000
There are graphitizable carbon (soft carbon) that easily becomes graphite by heating at ℃ and hardly graphitizable carbon (hard carbon) that hardly becomes graphite. Specifically, for example, graphite, cokes (such as petroleum coke, pitch coke, and needle coke), resin film fired carbon, fiber fired carbon, and vapor grown carbon are used.

Particularly, among the carbon materials, in the case of the present invention, a non-graphite carbon material having a disordered crystal structure is preferable.
By using a non-graphite-based carbon material, charge acceptability can be improved. Non-graphite carbon materials, for example,
It can be manufactured by heat-treating petroleum pitch, polyacene, polyparaphenylene, polyfurfuryl alcohol, polysiloxane, etc., and can be made into hard carbon or soft carbon by changing the firing temperature. is there. For example, 500 ° C
A firing temperature of about 800 ° C. is suitable for manufacturing hard carbon, and a firing temperature of about 800 ° C. to 1000 ° C. is suitable for manufacturing soft carbon.

Further, among the non-graphitic carbon materials, non-graphitizable carbon is preferable, and the cycle life at high temperatures can be improved. In particular, among the non-graphitizable carbons, the value of the plane spacing d ₀₀₂ in the C-axis direction obtained by the X-ray diffraction method is 0.3.
It is preferable to use a non-graphitizable carbon having a thickness of 6 nm or more and 0.40 nm or less, and the combination of the specific positive electrode active material and the positive electrode coating weight provides good charge acceptability and high cycle life at high temperatures, and also has a high output. A battery having a high density and excellent high-rate discharge characteristics is realized. In addition, the surface distance d
_{When the 002} value is less than 0.36 nm, the acceptability of charging is remarkably reduced. When the interplanar spacing d ₀₀₂ value is more than 0.40 nm, the true density of the carbon material becomes too small, and the energy density of the battery increases. Is not preferred.

Then, lithium manganate prepared using such a material is used as a positive electrode active material, and a coating weight of a positive electrode active material mixture containing the positive electrode active material on one surface of the current collector is 0.8 g. / 100cm ² or more 1.3g / 100
cm ² or less, and the plane spacing d ₀₀₂ value in the C-axis direction obtained by the X-ray diffraction method is from 0.36 nm to 0.40 nm.
A non-aqueous electrolyte lithium secondary battery characterized by using the following non-graphitizable carbon as a negative electrode active material has good characteristics as a battery for a hybrid electric vehicle, particularly suitable for use as a battery for a hybrid electric vehicle. That is, a battery having high output, good charge acceptability, and excellent high-temperature life characteristics is provided.

A negative electrode active material mixture using a carbon material as a negative electrode active material usually comprises a carbon material and a binder, and the same binder as that used in the positive electrode is used. When such a mixture is used as a paste, for example, the binder 2 is added to 100 parts by weight of the carbon material.
~ 20 parts by weight and 30-300 parts by weight of the solvent are mixed.

As the separator, a microporous film (for example, material: polyethylene, polypropylene) separator, an organic polymer electrolyte (for example, a complex of a polyether such as PEO and an alkali metal salt, polyvinylidene fluoride,
A gel-like material in which an electrolyte solution is contained in an organic polymer such as PAN), an inorganic solid electrolyte, or the like. In addition to a sheet-like material, a form directly formed on the surface of a positive electrode or a negative electrode sheet And the like can be used.

Examples of the non-aqueous electrolyte include propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone,
At least one kind of aprotic organic solvent such as 1,2-dimethoxyethane and tetrahydroxyfuran may be added to various lithium salts, for example, LiClO ₄ , LiBF ₆ , L
iPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , Li
It can be used a solution obtained by dissolving AsF ₆ or the like.

The battery of the present invention comprises the above-mentioned components. For example, the positive electrode and the negative electrode are formed into a sheet shape, and these electrodes are separated through a separator as a separator, for example.
It is preferably configured by adopting a spiral structure wound in a roll shape. The sheet-shaped electrode plate is manufactured by, for example, applying a paste-like electrode mixture on a current collector sheet such as a metal foil such as copper or aluminum by a reverse roll method, a doctor blade method, or the like. The sheet-shaped electrode coated with is subjected to hot air drying or vacuum drying, and then uniformly pressed and compressed by a roll press machine, and has an electrode porosity of about 25 to 5
It is uniformly adjusted to a range of 0%. Then, the sheet-shaped electrode plates manufactured by these methods are cut into a length of one battery such as a cylinder, a long cylinder, and a square, and an electrode plate group in which a positive electrode sheet, a separator, and a negative electrode sheet are sequentially laminated is formed. It is wound in a roll around the core material and stored in a battery container.

[0021]

EXAMPLES Example 1 Four types of long cylindrical batteries having the same battery size and different active material application weights were produced.

First, a positive electrode sheet was prepared. 89 of LiMn _1.95 Al _0.05 O ₄ having an average particle size of 13 μm was used as an active material.
Parts by weight (when Mn is partially replaced by Al, 5% to 7% is preferable), and acetylene black as a conductive agent is mixed in a ratio of 4 parts by weight, and further, polyvinylidene fluoride is used as a binder. Was added at a ratio of 7 parts by weight, N-methyl-2-pyrrolidone was added as a solvent, and the mixture was kneaded to prepare a slurry-type positive electrode mixture coating solution. Then
This positive electrode mixture coating solution was applied to both sides of an aluminum foil having a thickness of 15 μm so as to have the same application weight, one by one. In addition, in order to compare the differences depending on the application weight, four types of positive electrode sheets having different application weights were prepared as shown in Table 1 below.

Next, a negative electrode sheet was prepared. 94 parts by weight of soft carbon having an average particle diameter of 11 μm as an active material, 6 parts by weight of polyvinylidene fluoride as a binder, N-methyl-2-pyrrolidone as a solvent, kneading, and slurry formation A positive electrode mixture coating solution was prepared. Next, this negative electrode mixture coating solution was applied to both sides of a 10-μm-thick copper foil so as to have the same application weight, one surface at a time.
In addition, so that the utilization rate of the negative electrode is the same in each battery,
According to the capacity of the positive electrode, four types of negative electrode sheets having different application weights were prepared as shown in Table 1 below.

These positive and negative electrode sheets were dried with hot air and compressed by a roll press. The porosity was 37% for the positive electrode and 35% for the negative electrode.

Next, the positive and negative electrode sheets are wound in a roll shape through a polyethylene separator having a thickness of 30 μm to form a long cylindrical power generating element, which is 95 m in height.
m, width 60 mm, thickness 26 mm, and wall thickness 0.5 mm. After being accommodated in a stainless steel long cylindrical container, an electrolytic solution was injected and sealed. Thus, batteries A, B, C, and D were manufactured. The electrode area of the facing part of each battery is the same as that of battery A
In, 4719cm ^2, the battery B, 5564cm ^2, 6760cm ² in cell C, a 7800Cm ² battery D.
The electrolyte used was a solution obtained by dissolving 1M LiPF ₆ in a solvent in which EC and DEC were mixed at a ratio of 1: 1.

[0026]

[Table 1]

In order to compare the output characteristics of the batteries manufactured as described above, in a fully charged state (open terminal voltage is 4.1 V) at 25 ° C. and 5 A for 10 seconds,
Next, the battery was discharged for 10 seconds at 20 A and further for 10 seconds at 50 A, and the output value of each battery was obtained by extrapolating the current value at which the battery voltage became 2.5 V. FIG. 1 is a diagram showing the relationship between the output value of each battery thus obtained and the applied weight of the active material mixture of the positive electrode.

As shown in Table 1, as the weight of the battery increases, the capacity of the battery increases, and the capacity density per volume of the battery increases. However, as can be seen from FIG. 1, the output of the battery increases as the application weight decreases. From this, it can be seen that in order to increase the output, it is better to reduce the coating weight per unit area of the current collector, and by setting it to 1.3 g / 100 cm ² or less, a large output can be reliably obtained. I understand. Also, when the coating weight is less than 0.8 g, it is understood that the output starts to decrease, and it is understood that the coating weight per unit area of the current collector needs to be larger than a certain value,
It can be seen that a large output can be secured by setting it to 0.8 g / 100 cm ² or more.

Further, in order to compare the Wh capacity retention rate at the time of high rate discharge, continuous discharge at 1,5,10,16,20C was performed. It was found that the weight had the same correlation as the output with respect to the weight, and the coating weight was 0.8 g / 100 cm ² or more and 1.3 g /
It has been found that it is better to be 100 cm ² or less. By setting such a range, for example, the discharge capacity of 80% of the 1C discharge at the time of the 5C discharge cannot be ensured.
% Of discharge capacity can be secured.

FIG. 2 shows the Cole-Cole of the battery C obtained by measuring the AC impedance in the fully charged state.
It is a figure showing a plot. Table 2 below shows the electrode facing area of each battery, and the AC internal resistance and DC internal resistance at 1 kHz. Note that SOC indicates a charged state, where 0% is a state where the open terminal voltage is 2.7V, and 100% is a state where the open terminal voltage is 4.1V. DC resistance is
It is calculated from the voltage at the 10th second when discharging at a current of 5, 20, and 50A. The measurement conditions of the AC impedance were an applied voltage of 10 mV and a frequency of 0.001 to 100.
0 Hz, ambient temperature 25 ° C.

[0031]

[Table 2]

Although the Cole-Cole plot shows only that of the battery C, the value of the intercept with the real axis becomes smaller as the application weight becomes smaller and the diameter of the semicircle becomes larger from the measurement of each battery. It turned out that it was. This corresponds to the change in the AC resistance and the DC resistance in Table 2. The smaller the coating weight, the smaller the fixed resistance component such as the solution resistance, and on the other hand, the lower the reaction area of the electrode, the lower the interface resistance. This indicates that an increase has occurred. From this, it can be seen that the output increases by reducing the coating weight, and the high-rate discharge characteristics are improved. On the other hand, when the coating weight decreases too much, the decrease in the fixed resistance component decreases the interface resistance. It can be seen that there is a boundary value at which the effect of reducing the applied weight can be exerted because it is eliminated by the increase.

Example 2 Five types of long cylindrical batteries having the same battery size and different active material application weights were produced.

First, a positive electrode sheet was prepared. 89 of LiMn _1.95 Al _0.05 O ₄ having an average particle size of 13 μm was used as an active material.
Parts by weight (when Mn is partially replaced by Al, 5% to 7% is preferable), and acetylene black as a conductive agent is mixed in a ratio of 4 parts by weight, and further, polyvinylidene fluoride is used as a binder. Was added at a ratio of 7 parts by weight, N-methyl-2-pyrrolidone was added as a solvent, and the mixture was kneaded to prepare a slurry-type positive electrode mixture coating solution. Then
This positive electrode mixture coating solution was applied to both sides of an aluminum foil having a thickness of 15 μm so as to have the same application weight, one by one. In addition, in order to compare differences depending on the application weight, four types of positive electrode sheets having different application weights were prepared as shown in Table 3 below.

Next, a negative electrode sheet was prepared. 94 parts by weight of hard carbon having an average particle diameter of 11 μm as an active material, 6 parts by weight of polyvinylidene fluoride as a binder, N-methyl-2-pyrrolidone as a solvent are added, and the mixture is kneaded to form a slurry. A positive electrode mixture coating solution was prepared. Next, this negative electrode mixture coating solution was applied to both sides of a 10-μm-thick copper foil so as to have the same application weight, one surface at a time. The hard carbon used had a surface spacing d ₀₀₂ value in the C-axis direction obtained by an X-ray diffraction method using Cu-kα radiation of 0.3.
8 nm and obtained by heat-treating petroleum pitch at about 800 ° C. In addition, according to the capacity of the positive electrode, four types of negative electrode sheets having different application weights were prepared as shown in Table 3 below so that the utilization rate of the negative electrode was the same in each battery. Further, another type of negative electrode sheet was produced in the same manner as described above, except that artificial graphite having an average particle size of 11 μm was used instead of the hard carbon as the active material.

The positive and negative electrode sheets were dried with hot air and compressed by a roll press. The porosity was 37% for the positive electrode and 35% for the negative electrode.

Next, the positive and negative electrode sheets were wound in a roll shape through a polyethylene separator having a thickness of 30 μm to produce a long cylindrical power generating element, which was 95 m in height.
m, a width of 60 mm, a thickness of 26 mm, and a wall thickness of 0.5 mm were placed in a stainless steel container having a long cylindrical shape, and then an electrolyte was injected and sealed. Thus, the batteries E, F, G,
H and I were produced. The facing electrode area of each battery is:
Battery E, 4719 cm ² , Battery F, 5564c
m ^2, 6760cm ² in cell G and I, 7800 battery H
cm ² . Further, the electrolytic solution is a mixture of EC and DEC at 1:
1M LiPF ₆ dissolved in a solvent mixed at a ratio of 1 was used.

[0038]

[Table 3]

In order to compare the output characteristics of the batteries manufactured as described above, in a fully charged state (open terminal voltage is 4.1 V), the battery was manufactured at 25 ° C. and 5 A for 10 seconds.
Next, the battery was discharged for 10 seconds at 20 A and further for 10 seconds at 50 A, and the output value of each battery was obtained by extrapolating the current value at which the battery voltage became 2.5 V. FIG. 3 is a diagram showing the relationship between the output value of each battery thus obtained and the applied weight of the active material mixture of the positive electrode. Note that FIG. 3 and Table 3 also show the battery C manufactured in Example 1 for comparison.

As shown in Table 3, as the weight of the battery increases, the capacity of the battery increases, and the energy density per volume of the battery increases. However, as can be seen from FIG. 3, the output of the battery increases as the application weight decreases. Therefore, in order to increase the output, that it is better to reduce the coating weight per collector unit area know, larger output than the conventional by a 1.3 g / 100 cm ² or less can be obtained I understand. Further, it is understood that when the coating weight is less than 0.8 g, the output starts to decrease, and it is understood that it is not good to reduce the output in consideration of the decrease in the energy density and the like. For this reason, the coating weight per unit area of the current collector is preferably 0.8 g / 100 cm ² or more.

Further, in order to compare the Wh capacity retention rate at the time of high rate discharge, continuous discharge was performed at 1, 5, 10, 16, and 20C. It was found that the weight had the same correlation as the output with respect to the weight, and the coating weight was 0.8 g / 100 cm ² or more and 1.3 g /
It has been found that it is better to be 100 cm ² or less. By setting such a range, for example, the discharge capacity of 80% of the 1C discharge at the time of the 5C discharge cannot be ensured.
% Of discharge capacity can be secured.

Table 4 below shows the electrode facing area and 1 k of each battery.
It is a table | surface which shows AC internal resistance and DC internal resistance in Hz. SOC indicates the state of charge, 0% indicates a state where the open terminal voltage is 2.75V, and 100% indicates a state where the open terminal voltage is 4.75V.
It is a state of 1V. The DC resistance is calculated from the voltage at the 10th second when discharging at a current of 5, 20, 50 A.
The measurement conditions of the AC impedance are as follows.
mV, frequency 0.001 to 1000 Hz, ambient temperature 25
° C.

[0043]

[Table 4]

Cole-Co for the battery of this embodiment
In the le plot, as in the case of Example 1, it was found that the value of the intercept with respect to the real number axis became smaller as the weight of the applied battery became smaller, and the diameter of the semicircle became larger. This corresponds to the changes in the AC resistance and the DC resistance in Table 4. The smaller the coating weight, the smaller the fixed resistance component such as the solution resistance, while the smaller the reaction area of the electrode. This indicates that an increase has occurred. It can be seen that the output is increased by reducing the coating weight and the high-rate discharge characteristics are improved.On the other hand, when the coating weight is reduced too much, the decrease in the fixed resistance component is offset by the increase in the interface resistance. Therefore, it can be seen that there is a boundary value at which the effect of reducing the application weight can be exerted.

Further, in order to compare the input characteristics indicating the charge acceptability of the battery, the battery was completely discharged (the open terminal voltage was 2.75).
V) at 25 ° C. and 5 A for 10 seconds, then 10
By charging for 10 seconds at A and further for 10 seconds at 30 A, the input value of each battery was determined by extrapolating the current value at which the battery voltage was 4.2 V. Table 5 below shows the input values of Battery G, Battery C, and Battery I obtained in this manner.

[0046]

[Table 5]

As can be seen from Table 5, in battery I using artificial graphite as the negative electrode material, input values smaller than those of batteries G and C using the same electrode facing area and using hard carbon or soft carbon as the negative electrode material were obtained. It turns out that it shows. This is because non-graphitic carbon materials such as hard carbon with a disordered crystal structure have more sites to absorb lithium ions than artificial graphite with a uniform crystal structure, so when charged with a large current. In addition, because the lithium ions are quickly absorbed into the crystal structure of carbon, in the battery of the present invention, in order to further improve the charge receiving characteristics, a non-graphite-based carbon material is used. Is good.

Further, in order to compare the cycle life characteristics of the battery at a high temperature, the battery temperature was set to 45 ° C., and 1CA,
The battery is charged at a constant current and a constant voltage of 4.1 V for 3 hours, and then discharged at a constant current of 1 CA until the terminal voltage becomes 2.75 V. For I, the relationship between the number of cycles and the capacity retention was examined. The result is shown in FIG.

From the results shown in FIG. 4, it can be seen that the battery using hard carbon has the best cycle life characteristics at high temperature, followed by the battery using graphite and the battery using soft carbon. . Thus, in the battery of the present invention, by using hard carbon as the negative electrode active material, it is possible to produce a battery having good charge acceptability and excellent cycle life characteristics at high temperatures. I understand.

[0050]

According to the battery of the present invention, a battery having a large output and excellent high-rate discharge characteristics can be put to practical use. In addition, by using hard carbon for the negative electrode, a battery having excellent input characteristics and high-temperature cycle characteristics can be put to practical use.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the output value of a battery and the active material mixture application weight of a positive electrode.

FIG. 2 is a diagram showing a Cole-Cole plot of a battery C.

FIG. 3 is a diagram showing a relationship between an output value of a battery and a weight of an active material mixture applied to a positive electrode.

FIG. 4 is a diagram showing the relationship between the number of cycles and the capacity retention.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H029 AJ02 AJ05 AK03 AL06 AL07 AM01 AM03 AM07 BJ02 HJ01 HJ13 5H050 AA02 BA17 CA09 CB07 DA04 GA22 HA01 HA12 HA13

Claims (3)

[Claims] Claims: 1. A lithium manganate is used as a positive electrode active material,
The coating weight of the positive electrode active material mixture containing the positive electrode active material on one surface of the current collector is 0.8 g / 100 cm ² or more and 1.3.
g / 100 cm ² or less. 2. The non-aqueous electrolyte secondary battery according to claim 1, wherein a non-graphite carbon material is used as the negative electrode active material. 3. The non-graphite carbon material has a C-axis plane spacing d ₀₀₂ value of 0.36 n obtained by an X-ray diffraction method.
3. The non-aqueous electrolyte secondary battery according to claim 2, wherein the non-aqueous electrolyte secondary battery is a non-graphitizable carbon having a diameter of not less than m and not more than 0.40 nm.