JP2002151054A - Coin type nonaqueous electrolytic liquid secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress rise in resistance to electric charge motion and a diffusion resistance of a coin type secondary battery in that a positive plate, a separator, and a negative plate are laminated and contained in the battery, and then to improve charge/discharge characteristic. SOLUTION: The coin type secondary battery is constituted so that a thickness of the positive pole plate is 0.1 to 1.2 mm and an electric conduction agent to a positive pole mix is 8.2 to 14.0 weight %.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coin-type non-aqueous electrolyte secondary battery, and more particularly to a coin-type non-aqueous electrolyte secondary battery using a metal oxide such as lithium cobalt oxide as a positive electrode active material and a carbon material as a negative electrode active material. The present invention relates to the structure of a water electrolyte secondary battery.

[0002]

2. Description of the Related Art In recent years, with the rapid development of electronic technology, the performance of electronic and communication devices such as mobile phones and camcorders has been improved.
As miniaturization is progressing, there is also a demand for miniaturization and high energy density of secondary batteries mounted on these electronic and communication devices. As a secondary battery with high energy density,
Cylindrical and prismatic lithium-ion batteries using a metal oxide for the positive electrode and a carbon material for the negative electrode are known, but mass production will be possible in response to further miniaturization and thinning while maintaining a high energy density. For this reason, coin-type lithium secondary batteries have been developed.

Conventionally, in coin-type lithium secondary batteries, a disk-shaped positive / negative electrode plate is placed in a coin-type positive / negative battery case.
It has a structure of being stacked via a separator. As the positive electrode active material used for the positive electrode plate, an oxide or sulfide of a transition metal, such as manganese dioxide (MnO ₂ ) or molybdenum disulfide (MoS ₂ ), is used. As a substance, a substance using lithium metal or a lithium alloy has been proposed. However, batteries using these active materials have the problem that the surface of lithium metal or lithium alloy is roughened by repeated charging and discharging, and sufficient cycle characteristics cannot be obtained.

In a conventional cylindrical lithium ion battery having a spiral structure, by reducing the thickness of the electrode plate and increasing the length of the electrode plate, the charge transfer resistance and the diffusion resistance in the electrode thickness direction can be compared. The size can be easily reduced.

[0005]

By the way, in a coin-type secondary battery, a metal oxide is used for the positive electrode and a carbon material is used for the negative electrode as in the case of the cylindrical lithium-ion battery, in order to solve the above-mentioned disadvantages in the charge / discharge cycle. When used, the electrode plate area is limited due to the structure, so the electrode plate needs to be thickened to some extent. As a result, the charge transfer resistance and the diffusion resistance in the electrode increase, causing a problem that the charge / discharge characteristics deteriorate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to suppress the rise in charge transfer resistance and diffusion resistance of the above-mentioned coin-type secondary battery, and to improve charge / discharge characteristics.

[0007]

According to the present invention, there is provided a plate-like positive electrode plate comprising a positive electrode mixture comprising a positive electrode active material comprising a metal oxide, a conductive agent and a binder, and electrochemically storing and releasing lithium. A plate-shaped negative electrode plate made of a possible carbon material, a separator interposed between the positive and negative electrode plates, and a coin-type non-aqueous electrolyte secondary battery having a non-aqueous electrolyte solution, wherein the positive electrode plate The thickness is 0.1 mm to 1.2 mm, and the conductive agent is contained at 8.2% to 14.0% by weight with respect to the positive electrode mixture.

[0008] The positive electrode mixture of the secondary battery is characterized in that the conductive agent is contained in an amount of 9.0 to 11.5% by weight.

The reason for limiting the thickness of the positive electrode plate to 0.1 mm to 1.2 mm in the secondary battery of the present invention is that a certain capacity can be ensured and the positive electrode active material is effectively used. Further, the reason why the amount of the conductive agent is set to 8.2% by weight to 14.0% by weight is that the positive electrode active material is effectively used and the charge / discharge efficiency is increased by forming a good quality film on the electrode. is there.

However, when the thickness of the positive electrode plate is less than 0.1 mm, the capacity is too small and the durability is reduced because the electrode is thin. On the other hand, when the thickness of the positive electrode plate is larger than 1.2 mm, the durability of the electrode is increased, but the diffusion resistance and the charge transfer resistance in the thickness direction are too large. Further, when the amount of the conductive agent is lower than 8.2% by weight, the amount of the conductive agent is too small to effectively use the positive electrode active material. When the amount of the conductive agent is larger than 14.0% by weight, the conductive agent reacts with the electrolytic solution. However, the energy used for the film is too large to lower the charge / discharge efficiency.

Further, when the thickness of the positive electrode plate is 0.3 mm to 0.8 mm, the effect obtained at 0.1 mm to 1.2 mm becomes more remarkable, so that the charge / discharge characteristics are further improved, and the amount of the conductive agent in the positive electrode mixture is increased. Is 9.0% by weight to 11.5% by weight, the effect obtained at 8.2% by weight to 14.0% by weight is further remarkable, so that the charge / discharge characteristics are further improved.

Further, in the secondary battery according to the present invention, the particle diameter of the positive electrode active material is 2 μm to 20 μm. Further, the packing density of the positive electrode mixture was set to 2.6 gcm-
^It should be ^{3 to} 3.1 g · cm- ³ .

When the particle size of the positive electrode active material is 2 μm to 20 μm, the positive electrode active material, the conductive agent and the binder are uniformly mixed, so that the charge / discharge characteristics are further improved. Also, when the packing density of the positive electrode of ^{2.6 g · cm- 3 ~3.1g · cm-} 3, the charge-discharge characteristics are further improved because the positive electrode active material is fully utilized.

The reason is that when the particle size of the positive electrode active material is smaller than 2 μm, the conductive agent cannot sufficiently cover the periphery of the positive electrode active material, and the positive electrode active material is easily dissolved in the electrolyte. On the other hand, when the particle size of the positive electrode active material is larger than 20 μm, the positive electrode active material and the conductive agent cannot be mixed evenly,
This is because the surface in contact with the electrolyte is reduced.

Further, when the filling density of the positive electrode mixture comprising the positive electrode active material, the conductive agent and the binder is smaller than 2.6 g · cm- ³ ,
This is because the positive electrode active material, the conductive agent, and the binder are not uniformly mixed, and the capacity per volume of the positive electrode decreases. On the other hand, if the packing density is larger than 3.1 g · cm− ³ , the conductive agent cannot sufficiently and uniformly cover the positive electrode active material due to excessive pressure.

In the secondary battery of the present invention, the positive electrode plate is formed by, for example, pressing a positive electrode mixture obtained by mixing a positive electrode active material comprising a lithium-containing transition metal composite oxide, a conductive agent and a binder. It is molded. Further, the negative electrode plate is composed of, for example, a mixture of a negative electrode active material composed of a carbon-based material capable of electrochemically storing and releasing lithium, a conductive agent, and a binder. For these positive and negative electrode plates, it is preferable to use a conductive sponge-like holder or the like in order to maintain strength or increase conductivity. As the sponge-like holder used for the positive electrode plate,
A porous conductive material having a porosity of about 80% to 99% and a thickness of 0.3 mm to 20 mm is preferable, and the main material is more preferably aluminum or stainless steel. On the other hand, the sponge-like holder used for the negative electrode plate has a porosity of about 80% to 99% and a thickness of 0.3 mm to 2 mm.
A porous conductive material of 0 mm is preferable, and its main material is preferably nickel sponge. This sponge-like holder does not need to be separately considered as the thickness of the positive electrode plate.

The positive electrode active material composed of an oxide used for the positive electrode plate includes LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiMnO ₂ , MnO ₂ containing lithium (Li), LiCo _0.5 Ni _0.5 O ₂ , LiCo
_{0.2 Ni 0. 8 O 2, LiCo} 0.7 Ni 0.2 Mn 0.1 O 2 can be exemplified. Examples of the negative electrode active material used for the negative electrode plate include carbon materials such as graphite (natural graphite and artificial graphite) capable of electrochemically storing and releasing lithium, coke, and a fired organic material.

The conductive agent used for these positive and negative electrode plates includes:
Examples include carbon materials such as natural graphite (flaky graphite, earthy graphite, etc.), artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber and the like. here,
As the conductive agent used for the positive electrode plate, a combination of graphite and acetylene black is preferable, and the ratio of graphite to acetylene black is optimally 3/7 to 7/3.

Further, as the binder used for the positive and negative electrode plates,
Polytetrafluoroethylene, polyvinylidene fluoride,
Examples thereof include polyvinyl pyrrolidone, polyvinyl chloride, polyethylene, polypropylene, ethylene-propylene-diene polymer, styrene butadiene rubber, carboxymethyl cellulose, fluoro rubber, and polyamic acid. Here, as the binder used for the positive electrode plate, polyvinylidene fluoride is preferable, and the amount of the binder added is 1% by weight.
-10% by weight is preferred, and 3-6% by weight is more preferred.

The electrochemical capacity of the active material of the positive electrode plate and the negative electrode plate in the battery of the present invention is such that the capacity of the positive electrode plate is smaller than the capacity of the negative electrode plate.
It is preferably 0.80 times to 1.20 times, and more preferably 0.90 times to 1.10 times.

Further, examples of the separator that electrically insulates the positive and negative electrode plates include an electrolyte-absorbing material such as a polypropylene nonwoven fabric, a microporous polypropylene film, and a microporous polypropylene nonwoven fabric.

As the solvent of the non-aqueous electrolyte solution impregnated in the separator, ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (γ-GBL)
And a mixed solvent of a cyclic carboxylic acid ester such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and a chain carboxylic acid ester such as methyl acetate (MA). Cyclic ethers such as tetrahydrofuran (THF), 1,2
-A solvent to which a chain ether such as dimethoxyethane (DME) is added is exemplified. Among these solvents, it is preferable to contain dimethyl carbonate, it is preferable to have dimethyl carbonate and ethylene carbonate, and it is more preferable to contain dimethyl carbonate, ethylene carbonate and ethyl methyl carbonate, and the amount of ethylene carbonate is 25 Volume% to 40 volume% is particularly preferred.

Further, as the solute of the non-aqueous electrolyte, lithium hexafluorophosphate (LiPF ₆ ), LiBF ₄ , LiSbF ₆ , LiAsF ₆ ,
Salts of inorganic acids such as LiClO ₄ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ S
Organic acid salts such as O ₂ ) ₂ and LiC (CF ₃ SO ₂ ) ₃ are exemplified. Among these solutes, lithium hexafluorophosphate is preferred. The amount of the solute to be added is preferably 0.8 mol / l to 1.6 mol / l, and particularly preferably 1.0 mol / l to 1.4 mol / l.

The positive electrode case and the negative electrode case constituting the coin-type secondary battery of the present invention are formed into a bottomed cylindrical shape by pressing stainless steel or the like. A mesh made of stainless steel, aluminum, titanium, etc. is applied to the inner bottom surface of the positive electrode case by applying a conductive paint mixed with graphite powder and water glass to increase the conductivity between the positive electrode plate and the positive electrode case. Can be used. Also, on the inner bottom surface of the negative electrode case, a conductive paint or the like made of a mixture of graphite powder and water glass is applied to increase the conductivity between the negative electrode plate and the negative electrode case, or a mesh made of stainless steel, copper, or the like. It is preferable to use a negative electrode current collector in a shape of a circle.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Experiment 1] In Experiment 1, the effect of the amount of a conductive agent on the positive electrode plate of a coin-type secondary battery on battery characteristics was examined. (Examples 1 to 5) First, the production of a positive electrode plate will be described.

A mixture of lithium carbonate (Li ₂ CO ₃ ) and tricobalt tetroxide (Co ₃ O ₄ ) is calcined in air at 900 ° C. to produce lithium cobaltate (LiCoO ₂ ) as a metal oxide. The fired product is jet-milled to an average particle size of 10 μm
The material crushed until it becomes the positive electrode active material. A mixture of graphite and acetylene black at a weight ratio of 1: 1 was used as a conductive agent, and polyvinylidene fluoride was used as a binder. The positive electrode active material, the conductive agent and the binder were mixed at a weight ratio of 8
6.8: 8.2: 5.0 Kneading to adjust the positive electrode mixture, and kneading and granulating the positive electrode mixture under pressure to form a 20 m diameter.
m, a thickness of 0.6 mm, and a packing density of 2.8 g · cm- ³ were prepared. As a result, the conductive agent is contained at 8.2% by weight with respect to the positive electrode mixture.

Next, as an anode plate, 2% by weight of an aqueous dispersion of carboxymethyl cellulose as a thickener was kneaded with artificial graphite as a carbon material as an active material,
1 aqueous solution of styrene butadiene latex as a binder
By weight kneading, a slurry-like negative electrode mixture was obtained. This negative electrode mixture was filled in a nickel sponge, dried, rolled and punched out to produce a negative electrode plate 2 having a diameter of 21 mm and a thickness of 0.9 mm.

The filling rate and density of the negative electrode mixture can be adjusted by changing the thickness of the nickel sponge before filling the mixture, the amount of the mixture charged, and the rolling conditions. The density of the mixture is adjusted to 1.0 g · cm- ³ using nickel sponge.

The separator used was a microporous film made of polypropylene punched out to a diameter of 22 mm.

Then, in a separately prepared negative electrode case, the negative electrode plate, the separator and the positive electrode plate are superposed and arranged in this order, and an insulating packing is attached. Thereafter, ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) as solvents were mixed at a volume ratio of 1: 1: 1.
With lithium hexafluorophosphate (LiP
A non-aqueous electrolyte solution obtained by dissolving F ₆ ) at 1.2 mol / L was injected, covered with a positive electrode case, and sealed by crimping to produce a battery A1 of the present invention.

FIG. 1 is a sectional view of a coin-type non-aqueous electrolyte secondary battery of the present invention. As shown in FIG. 1, a negative electrode plate 3, a separator 4 and a positive electrode plate 5 are stacked inside a sealed negative electrode case 1 and a closed positive electrode case 2 and housed with an insulating packing 6 interposed therebetween. .

Further, as Examples 2 to 5, the weight ratio of the positive electrode active material, the conductive agent and the binder in the positive electrode plate was 86.0: 9.
0: 5.0, 85.0: 10.0: 5.0, 83.5: 11.5: 5.0, 81.0: 1
Battery A2 of the present invention (containing 9.0% by weight of a conductive agent), Battery A3 of the present invention (containing 10.0% by weight of a conductive agent), and a battery of the present invention under the same conditions as in Battery A1 of the present invention except that the ratio was changed to 4.0: 5.0. Battery A4 (containing 11.5% by weight of the conductive agent) and Battery A5 of the present invention (containing 14.0% by weight of the conductive agent) were produced. <Comparative Examples 1 and 2> The weight ratio of the positive electrode active material, the conductive agent, and the binder in the positive electrode plate was 89.0: 6.0: 5.0, 79.0: 16.0: 5.
A comparative battery X1 (containing 6.0% by weight of a conductive agent) and a comparative battery X2 (containing 16.0% by weight of a conductive agent) were manufactured under the same conditions as the battery A1 of the present invention except that the battery was changed to 0. <Evaluation Test> Batteries A1 to A5 of Present Invention and Comparative Battery X
1. For each battery of Comparative Battery X2, the charge / discharge characteristics of the battery were evaluated. This charge / discharge characteristic was measured at an ambient temperature of 25 ° C.
At a constant current of 3 mA, a charge / discharge test was performed with a charge end voltage of 4.2 V and a discharge end voltage of 3.0 V, and the discharge capacity and charge / discharge efficiency of each battery were examined.

The results are shown in Table 1.

[0034]

[Table 1]

According to Table 1, the amount of the conductive agent in the positive electrode plate was 8.
In the case of 2 wt% to 14.0 wt%, the discharge capacity and charge / discharge characteristics were high, and the battery characteristics could be improved by setting the amount of the conductive agent to 9.0 wt% to 11.5 wt%. [Experiment 2] In Experiment 2, the effect of the thickness of the positive electrode plate on the positive electrode plate of the coin-type secondary battery on battery characteristics was examined. <Examples 6 to 9> Except that the weight ratio of the positive electrode active material, the conductive agent, and the binder was 85.0: 10.0: 5.0, the thickness of the positive electrode plate was changed to 0.1 mm, and the thickness of the negative electrode plate was changed to 0.15 mm, Battery A of the Present Invention
Battery B1 of the present invention (containing 10.0% by weight of a conductive agent) was produced under the same conditions as in Example 1.

Further, the thickness of the positive electrode plate and the negative electrode plate is set to 0.3 mm
Batteries B2, B3, and B4 of the invention were produced under the same conditions as those of the battery B1 of the invention except that the thickness was changed to 0.45 mm, 0.8 mm, 1.2 mm, 1.2, and 1.8 mm. Comparative Examples 3 and 4 Comparative batteries Y1 and Y2 were prepared under the same conditions as Battery B1 of the present invention except that the thicknesses of the positive electrode plate and the negative electrode plate were changed to 0.05 mm and 0.75 mm, 1.4 mm and 2.1 mm. Produced. <Evaluation Test> Batteries B1 to B4 of Present Invention and Comparative Battery Y
1. The battery of Comparative battery Y2 was tested under the same conditions as in Experiment 1, and the discharge capacity and charge / discharge efficiency of each battery were examined.

Table 2 shows the results. In addition, the battery A of the present invention
No. 3 was produced in Experiment 1 above.

[0038]

[Table 2]

As shown in Table 2, when the thickness of the positive electrode plate was 1.2 mm or less, the charge / discharge efficiency was maintained high.
It was found that the charge and discharge efficiency was even higher when the thickness was 0.8 mm or less. When the thickness of the positive electrode plate is 0.1 mm or more, the durability of the positive electrode plate increases and the battery capacity exceeds 10 mAh, so that the positive electrode plate can be used for various applications such as watches, calculators, and backup memories. The thickness of the positive electrode plate is 0.3mm
In the case described above, the durability of the positive electrode plate is further increased, and the usage is expanded because the battery capacity is as large as 30 mAh or more.

Although the diameter of the battery studied this time is 21 mm, similar results are obtained when the battery diameter is 5 mm, 10 mm, and 30 mm. Thus, even when the battery size is changed, a battery with high charge / discharge characteristics can be manufactured by setting the amount of the conductive agent in the positive electrode plate to 8.2% by weight to 14.0% by weight and the thickness of the positive electrode plate to 0.1 to 1.2 mm. [Experiment 3] In Experiment 3, the effect of the particle size of the positive electrode active material on the positive electrode plate of the coin-type secondary battery on battery characteristics was examined. <Examples 10 to 12> Production of a positive electrode plate will be described. First,
Lithium cobalt oxide, which is a metal oxide, was pulverized by a jet mill until the average particle size became 10 μm, and was prepared as a positive electrode active material. A mixture of graphite and acetylene black at a weight ratio of 1: 1 is used as a conductive agent, and polyvinylidene fluoride is added to n-methylpyrrolidone (NMP) at 10% by weight.
The solution was prepared as a binder. The positive electrode active material, the conductive agent, and the binder were kneaded at a weight ratio of 85.0: 10.0: 50.0 to obtain a slurry mixture. When the slurry mixture was dried, the weight ratio of the positive electrode active material: the conductive agent: the binder in the positive electrode mixture was 85.0: 10.0: 5.0, and the weight of the conductive agent was 10.0% by weight based on the positive electrode mixture. It will be contained. This positive electrode mixture was filled in an aluminum sponge and dried, and then the packing density of the positive electrode mixture was 2.8 gcm.
-Rolled to ³ and punched out, diameter 20mm, thickness
A 0.7 mm positive electrode plate was produced.

On the other hand, as a negative electrode plate, an artificial graphite was kneaded with 2% by weight of an aqueous dispersion of carboxymethylcellulose as a thickener, and a 1% by weight aqueous solution of styrene butadiene latex was kneaded as a binder to form a slurry. After filling the mixture into nickel sponge and drying,
Rolled and punched (diameter 21 mm, thickness 0.9 mm) was used.

A battery C1 of the present invention was produced under the same conditions as the battery A1 of the present invention except that the positive electrode plate and the negative electrode plate were used.

Further, as Examples 11 and 12, lithium cobalt oxide as a metal oxide was jet-milled to have an average particle size of 2 μm.
m, and 20 μm, except that the positive electrode plate was used as a positive electrode active material.
Under the same conditions, a battery C2 of the present invention and a battery C3 of the present invention were produced. <Reference Examples 1 and 2> Except that lithium cobaltate was pulverized with a jet mill until the average particle diameter became 1 μm and 25 μm, respectively, and used as the positive electrode active material under the same conditions as the above-described battery C1 of the present invention. Battery D1, reference battery D2
Was prepared. <Evaluation Test> Batteries C1 to C3 of Present Invention and Reference Battery D
1. The battery of Reference Battery D2 was tested under the same conditions as in Experiment 1, and the discharge capacity and charge / discharge efficiency of each battery were examined.

Table 3 shows the results.

[0045]

[Table 3]

From Table 3, it was found that when the average particle diameter of the positive electrode active material in the positive electrode plate was 2 μm to 20 μm, the discharge capacity and charge / discharge efficiency were high. [Experiment 4] In Experiment 4, the effect of the packing density of the positive electrode active material in the positive electrode plate of the coin-type secondary battery on battery characteristics was examined. <Examples 13 and 14> An aluminum sponge was filled with a slurry-like positive electrode mixture, and after drying, the filling density of the positive electrode mixture was reduced.
A battery C5 of the present invention was produced under the same conditions as the battery C1 of the present invention except that the rolling was performed to 2.6 g · cm- ³ .

A battery C5 of the present invention was produced under the same conditions as the above-described battery C1 of the present invention, except that the positive electrode mixture was rolled so as to have a packing density of 3.1 g · cm− ³ . <Reference Examples 3 and 4> After filling a slurry-like positive electrode mixture into an aluminum sponge and drying, the filling density of the positive electrode mixture is
A reference battery D3 was made under the same conditions as the battery C1 of the invention except that the battery was rolled to 2.4 g · cm- ³ .

A reference battery D4 was prepared under the same conditions as the above-described battery C1 of the present invention except that the positive electrode mixture was rolled so that the packing density became 3.3 g · cm− ³ . <Evaluation Test> Each battery of the present invention battery C4, the present invention battery C5, the reference battery D3, and the reference battery D4 was tested under the same conditions as in the above Experiment 1, and the discharge capacity and charge / discharge efficiency of each battery were examined. .

The results are shown in FIG. 2 and Table 4. In addition, the battery C1 of the present invention was manufactured in the experiment 3.

[0050]

[Table 4]

From Table 4, it can be seen that the discharge capacity is increased by setting the packing density of the positive electrode mixture in the positive electrode plate to 2.6 g · cm− ³ or more, and the discharge density is set to 3.1 g · cm− ³ or less. The charge and discharge efficiency can be kept high.

[0052]

According to the present invention, an increase in charge transfer resistance and diffusion resistance of a coin-type secondary battery can be suppressed, and the charge / discharge characteristics of this type of secondary battery can be improved. Great value.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a battery.

FIG. 2 is a diagram showing a relationship between a filling density in a positive electrode plate, and charge / discharge efficiency and discharge capacity.

[Description of Signs] 1 Negative electrode case 2 Positive electrode case 3 Negative electrode plate 4 Separator 5 Positive electrode plate 6 Insulation packing

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Maruo Jinno 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. F-term (reference) 5H029 AJ02 AK03 AL07 AL08 AM03 AM04 AM05 AM07 BJ03 BJ16 DJ08 EJ04 HJ01 HJ04 HJ05 HJ08 5H050 AA02 AA19 BA17 CA08 CA09 CB07 DA02 DA10 EA09 EA10 EA24 HA01 HA04 HA05 HA08

Claims (4)

[Claims] 1. A plate-shaped positive plate made of a positive electrode mixture containing a positive electrode active material made of a metal oxide, a conductive agent and a binder, and a plate made of a carbon material capable of electrochemically storing and releasing lithium. A negative electrode plate, a separator interposed between the positive and negative electrode plates, and a coin-type non-aqueous electrolyte secondary battery having a non-aqueous electrolyte, wherein the thickness of the positive electrode plate is 0.1 mm to 1.2 mm. And the conductive agent is 8.2% by weight to 14.0% by weight based on the positive electrode mixture.
A coin-type non-aqueous electrolyte secondary battery characterized by being contained. 2. The coin-type non-aqueous electrolyte secondary battery according to claim 1, wherein the conductive agent is contained in an amount of 9.0% by weight to 11.5% by weight. 3. The particle size of the positive electrode active material is 2 μm to 20 μm.
The coin-type non-aqueous electrolyte secondary battery according to claim 1 or 2, wherein: 4. The packing density of the positive electrode mixture is 2.6 g · cm ⁻³ or less.
The coin-type non-aqueous electrolyte secondary battery according to claim 1, wherein the weight is 3.1 g · cm− ³ .