JP2000228192A - Non-aqueous electrolyte battery - Google Patents

Abstract

[Problem] To use nickel oxyhydroxide as a positive electrode active material,
In the case of a rectangular battery in the form of a wound electrode group, since the pressing force on the electrode plate is weak, nickel oxyhydroxide causes a volume change in the charging / discharging process, thereby lowering the current-collecting ability of the active material. The cycle life characteristics were poor due to the influence. Kind Code: A1 At least one or more positive electrode active materials selected from the group consisting of nickel oxyhydroxide, nickel oxyhydroxide containing lithium, nickel oxyhydroxide derivatives and lithium oxyhydroxide derivatives containing lithium are used. In this non-aqueous electrolyte battery, the battery case is of a rectangular parallelepiped type or a cubic type, and the electrode group is of a stacked type.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-aqueous electrolyte battery.

[0002]

2. Description of the Related Art In recent years, with the development of portable electronic devices, development of high-performance batteries has been desired. Lithium ion batteries using a carbon material for the negative electrode and lithium cobalt oxide, which is a composite oxide having a layered structure for the positive electrode, have been put into practical use as nonaqueous electrolyte batteries having a high operating voltage and a high energy density. However, since lithium cobaltate is scarce and expensive as a resource, a lithium-containing manganese composite oxide or lithium nickelate has been proposed as a substitute. These composite oxides are positive electrode active materials for a so-called 4V lithium secondary battery having an average operating voltage of about 4V. On the other hand, it is estimated that demand for 3V-based non-aqueous electrolyte secondary batteries will increase in the future from the viewpoint of development of ICs that operate at a low voltage of 3 V or less and battery safety. However, LiMn is generally known as a cathode active material for a 3V-based nonaqueous electrolyte secondary battery.
These materials are only nO ₂ and V ₂ O ₅ , and even these materials have many problems in terms of discharge capacity and cycle life characteristics, so they have very limited applications such as memory backup. It is currently used only by

On the other hand, it has recently been reported that nickel oxyhydroxide can be used as a positive electrode active material for a 3V-based non-aqueous electrolyte secondary battery (The 64th Annual Meeting of the Electrochemical Society, lecture number 3A06). According to this report, the theoretical discharge capacity of nickel oxyhydroxide is 290 mAh / g, which corresponds to a utilization rate of 5% or more of the theoretical discharge capacity.
It shows an initial discharge capacity as high as 5 mAh / g, and it can be said that it can be sufficiently used for applications requiring a battery with a high energy density, such as a power supply for a notebook computer. Therefore, nickel oxyhydroxide is expected as a promising candidate for a high-capacity 3V-based non-aqueous electrolyte secondary battery positive electrode active material. On the other hand, there is a growing need for rectangular or cubic prismatic batteries, because they can realize more effective use of space when incorporated into portable equipment than cylindrical batteries. Non-aqueous electrolyte batteries such as prismatic lithium-ion batteries have relatively thin electrodes coated with an active material layer using a metal foil or the like as a current collector substrate to cover the slow diffusion rate of the electrolyte in the non-aqueous electrolyte. It is usual that the plate is wound together with a separator to form a rolled electrode plate group, which is inserted into a case to manufacture. However, in the case of such a battery, the peripheral portion of the case and the center of the electrode plate element form a gap, which lowers the energy density of the battery and weakens the pressing force on the electrode plate.

[0004]

However, nickel oxyhydroxide has a drawback that cycle life characteristics are not good. The improvement of the cycle life performance is a major problem for practical use, and a solution is awaited. One of the causes is considered to be that the adhesiveness between the active material and the conductive agent or the current collector substrate was reduced due to the volume change in the charge and discharge process of nickel oxyhydroxide, and the current collector of the active material was reduced. Can be

In particular, in a rectangular battery in which nickel oxyhydroxide is used as a positive electrode active material and a rolled electrode group is used, since the pressing force on the electrode plate is weak, the nickel oxyhydroxide is not charged during the charging and discharging process. Due to the change in volume, the current collecting property of the active material was reduced, and the cycle life characteristics were deteriorated due to the effect.

[0006]

The non-aqueous electrolyte battery according to the present invention comprises a group consisting of nickel oxyhydroxide, lithium oxyhydroxide containing lithium, a derivative of nickel oxyhydroxide and a derivative of nickel oxyhydroxide containing lithium. The battery case comprises at least one or more positive electrode active materials selected from the group consisting of: a battery case having a rectangular parallelepiped type or a cubic type; and a group of electrode plates being stacked. It is characterized in that one is wrapped in a separator. Here, the “derivative of nickel oxyhydroxide and the derivative of nickel oxyhydroxide containing lithium” are “nickel oxyhydroxide containing any different element or nickel oxyhydroxide containing any different element and lithium” Means

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A non-aqueous electrolyte battery according to the present invention
At least one compound selected from the group consisting of nickel oxyhydroxide, nickel oxyhydroxide containing lithium, a derivative of nickel oxyhydroxide, and a derivative of nickel oxyhydroxide containing lithium is used as the positive electrode active material. Further, in the nonaqueous electrolyte battery according to the present invention, the battery case is a rectangular parallelepiped type or a cubic type, and the electrode group is not a wound type but a stacked type. Further, one of the positive electrode plate and the negative electrode plate is wrapped with a separator. As the separator, an insulating polyolefin microporous film such as polyethylene or polypropylene, a polymer solid electrolyte, a gel electrolyte in which an electrolyte is contained in a polymer solid electrolyte, or the like can be used. Further, an insulating microporous film and a solid polymer electrolyte may be used in combination. Further, when a porous solid polymer electrolyte membrane is used as the solid polymer electrolyte, the electrolyte contained in the polymer and the electrolyte contained in the pores may be different.

Further, the negative electrode of the nonaqueous electrolyte battery according to the present invention is
Occludes lithium or lithium ions as electrode material
A releasable substance may be used. An example is gold
With lithium, Al, Si, Pb, Sn, Zn, Cd, etc.
Alloy with lithium, LiFe _TwoO_Three, WO_Two, MoO_TwoEtc.
Transition metal oxides, carbonaceous materials such as graphite and carbon
Fee, Li_Five(Li_ThreeN) and the like;
Mixtures may be used. Also, the non-aqueous electrolyte according to the present invention
In batteries, the current collector base is made of aluminum on the positive electrode plate.
Metal foil such as copper foil can be used for foil and negative electrode plate
And inject electrolyte under reduced pressure to improve the efficiency of liquid penetration into the electrode group.
May be improved. The solvent of the electrolytic solution is
Cyclic such as ethylene carbonate and propylene carbonate
Carbonate, dimethyl carbonate and diethyl carbonate
Chain carbonate esters such as methylate and methyl ethyl carbonate
, Γ-butyrolactone, sulfolane, dimethyl sulfo
Oxide, acetonitrile, dimethylformamide,
Tilacetamide, 1,2-dimethoxyethane, 1,2
-Diethoxyethane, tetrahydrofuran, 2-methyl
Tetrahydrofuran, dioxolan, methyl acetate
Use a polar solvent such as
Can be. In addition, as a lithium salt that dissolves in organic solvents
Is LiPF₆, LiBF_Four, LiAsF₆, LiCF_ThreeC
O_Two, LiCF_ThreeSO_Three, LiN (SO_TwoCF_Three)_Two, LiN
(SO_TwoCF_TwoCF_Three)_Two, LiN (COCF_Three)_TwoAnd L
iN (COCF_TwoCF_Three)_TwoSalt or a mixture thereof
It may be a compound. The nonaqueous electrolyte battery according to the present invention has a positive electrode plate.
Is placed under uniform pressure, and the oxyhydroxide nickel
Of the positive electrode plate due to volume change during charging and discharging
Power can be suppressed and the cycle life is excellent.
Ponds can be made. Here, the separator is
Either electrode plate or negative electrode plate wrapped in separator
In addition to having the above features,
Battery that is less likely to cause short circuits.
You.

[0009]

The present invention will be described below with reference to preferred embodiments, but the scope of the present invention is not limited thereto.

Example 1 Nickel oxyhydroxide having a particle size of 5 to 50 μm was used as a positive electrode active material, 5 wt% of acetylene black was used as a conductive material, and n-methyl-2-pyrrolidone solution of polyvinylidene difluoride was used as a binder. (9 wt% as polyvinylidene difluoride solid content) in a dry room to form a paste, apply it to foamed nickel of the current collector, dry at 100 ° C., and press to a predetermined thickness. . This electrode plate was cut to produce a positive electrode plate having a size of 20 mm × 35 mm.

A lithium-containing graphite having an average particle diameter of 10 μm is used as a negative electrode active material, and n-methyl-2-pyrrolidone solution of polyvinylidene difluoride (9 wt% as polyvinylidene difluoride solid content) as a binder is dried. After mixing in a room to form a paste, the mixture was applied to foamed nickel of the current collector, dried at 100 ° C., and pressed to a predetermined thickness. Cut this electrode plate and measure 20mm
A negative electrode plate of × 35 mm was manufactured.

As a separator, a non-woven fabric made of polyolefin having a thickness of 150 μm and cut into a size of 21 mm × 37 mm was used. FIG. 1 is a schematic exploded perspective view of a non-aqueous electrolyte battery according to a first embodiment of the present invention. Is a positive electrode plate, 2a is a positive electrode plate tab, 3 is a separator, 4 is a battery case, 5 is a lid, 6 is a safety valve, and 21 is a positive electrode terminal.

As shown in FIG. 1, the positive electrode plate and the negative electrode plate are connected from the end to the negative electrode plate-separator-positive plate-separator-
In the order of negative electrode plate, five positive electrodes, six negative electrodes, and ten separators were stacked, and about half of the electrode plates were inserted into a rectangular parallelepiped iron case. After connecting the tabs of the positive electrode plate group to the lid with the safety valve, insulating plate, and positive electrode terminal, and connecting the tab portions of the negative electrode plate respectively, inject electrolyte into the case to completely close the electrode plate group. Inserted into the case. A mixed solvent of ethylene carbonate and diethyl carbonate containing 1 M lithium perchlorate was used as the electrolyte. The lid and the case body were laser-sealed to produce Battery A according to the present invention.

Example 2 Nickel oxyhydroxide having a particle diameter of 5 to 50 μm was used as a positive electrode active material, 5 wt% of acetylene black was used as a conductive material, and n-methyl-2-pyrrolidone solution of polyvinylidene difluoride was used as a binder. (9 wt% as polyvinylidene difluoride solid content) in a dry room to form a paste, apply it to foamed nickel of the current collector, dry at 100 ° C., and press to a predetermined thickness. . This electrode plate was cut to produce a positive electrode plate having a size of 20 mm × 35 mm. FIG. 2 is a schematic exploded perspective view of a method for laminating electrode plates and a battery in a nonaqueous electrolyte battery according to a second embodiment of the present invention.
6, 1a, 2a and 21 are the same as those in FIG.
Indicates a positive electrode plate wrapped with a separator. As shown in FIG. 2, the positive electrode plate was enveloped in a 150 μm-thick polyolefin nonwoven fabric as a separator.

Lithium-containing graphite having an average particle size of 10 μm is used as a negative electrode active material, and a solution of polyvinylidene difluoride in n-methyl-2-pyrrolidone (9 wt% as solid content of polyvinylidene difluoride) as a binder is dried. After mixing in a room to form a paste, the mixture was applied to foamed nickel of the current collector, dried at 100 ° C., and pressed to a predetermined thickness. Cut this electrode plate and measure 20mm
A negative electrode plate of × 35 mm was manufactured.

As shown in FIG. 2, the positive electrode plate and the negative electrode plate are arranged in the order of negative electrode plate-positive plate (enclosed in a separator) -negative plate-... 6
The sheets were stacked, and about half of the electrode plates were inserted into a rectangular parallelepiped iron case. After connecting the tab portion of the positive electrode plate group to the lid provided with the safety valve, the insulating plate and the positive electrode terminal, and also connecting the tab portion of the negative electrode plate, respectively, inject the electrolytic solution into the case,
The electrode group was completely inserted into the case. A mixed solvent of ethylene carbonate and diethyl carbonate containing 1 M lithium perchlorate was used as the electrolyte. The lid and the case body were laser-sealed to produce Battery B according to the present invention.

Conventional Example 1 Nickel oxyhydroxide having a particle size of 5 to 50 μm is used as a positive electrode active material, 5 wt% of acetylene black is used as a conductive material, and n-methyl-2-pyrrolidone solution of polyvinylidene difluoride is used as a binder. (9 wt% as polyvinylidene difluoride solid content) in a dry room to form a paste, apply it to foamed nickel of the current collector, dry at 100 ° C., and press to a predetermined thickness. . This positive electrode plate was cut into a size of 200 mm × 20 mm.

Lithium-containing graphite having an average particle diameter of 10 μm was used as a negative electrode active material, and a solution of polyvinylidene difluoride in n-methyl-2-pyrrolidone (9 wt% as solid content of polyvinylidene difluoride) as a binder was dried. After mixing in a room to form a paste, the mixture was applied to foamed nickel of the current collector, dried at 100 ° C., and pressed to a predetermined thickness. Cut this electrode plate and measure 200m
A negative electrode plate of mx 20 mm was manufactured.

As the separator, a polyolefin nonwoven fabric having a thickness of 150 μm cut into a size of 205 mm × 20 mm was used.

These positive and negative electrode plates are stacked in the order of negative electrode-separator-positive electrode-separator, and are wound into an elliptical spiral shape as viewed from the side sectional direction as shown in FIG. 3 to obtain an electrode plate element. The symbols 1 to 6 in FIG.
21 shows the same thing as FIG. After injecting the electrolyte into a rectangular iron case, inserting the electrode plate element half into the case, connecting the cover with the safety valve, insulating plate and positive electrode terminal to the positive electrode plate, and then completely inserting the electrode plate group into the case Inserted. A mixed solvent of ethylene carbonate and diethyl carbonate containing 1 M lithium perchlorate was used as the electrolyte. The lid and the case body were laser-sealed to produce a conventional battery C for comparison.

[Conventional Example 2] Nickel oxyhydroxide having a particle diameter of 5 to 50 μm is used as a positive electrode active material, 5 wt% of acetylene black is used as a conductive material, and n-methyl-2-pyrrolidone solution of polyvinylidene difluoride is used as a binder. (9 wt% as polyvinylidene difluoride solid content) in a dry room to form a paste, apply it to foamed nickel of the current collector, dry at 100 ° C., and press to a predetermined thickness. . This positive electrode plate was cut into a size of 270 mm × 60 mm.

A lithium-containing graphite having an average particle diameter of 10 μm was used as a negative electrode active material, and a solution of polyvinylidene difluoride in n-methyl-2-pyrrolidone (9 wt% as solid content of polyvinylidene difluoride) as a binder was dried. After mixing in a room to form a paste, the mixture was applied to foamed nickel of the current collector, dried at 100 ° C., and pressed to a predetermined thickness. Cut this electrode plate and measure 270m
A negative electrode plate of mx 60 mm was manufactured.

As the separator, a non-woven fabric made of polyolefin having a thickness of 150 μm and cut into a size of 275 mm × 60 mm was used.

These positive and negative electrode plates are stacked in the order of negative electrode-separator-positive electrode-separator and wound in a spiral shape to form an electrode plate element. Then, the electrode element is poured into a cylindrical iron case having an insulating plate at the bottom by injecting an electrolytic solution, the electrode element is half inserted into the case, and a lid provided with a safety valve, an insulating plate and a positive electrode terminal is provided. After connecting to the positive electrode plate via a lead, the electrode plate group was completely inserted into the case. A mixed solvent of ethylene carbonate and diethyl carbonate containing 1 M lithium perchlorate was used as the electrolyte. The lid and the case body were laser-sealed to produce a conventional battery D for comparison. FIG.
Shows the cross section of the battery fabricated in this way.
In FIG. 4, symbols 1 to 4 and 21 indicate the same components as in FIG. 1, 7 indicates an insulating plate, 11 indicates a negative electrode terminal, and 22 indicates a positive electrode lead.

[Battery Evaluation Test] The battery obtained by the above method was discharged at a constant current of 25 V at a current density of 3.5 mA / cm ² up to 2.0 V and then 3.5.
The battery was charged at a constant current up to 4.2 V at a current density of mA / cm ² and then at a constant voltage for 5 hours. In the same manner, charge and discharge for 100 cycles were repeated.

[Evaluation Results] FIG. 5 shows a change in the discharge capacity value of each battery (the discharge capacity at the first cycle is shown as 100%) as the charge / discharge cycle elapses. Comparing the conventional batteries C and D, the battery D which is a cylindrical battery
Shows relatively good cycle life characteristics, whereas battery C, which is a prismatic battery, has a large capacity deterioration due to cycling. This is because the cylindrical battery has a structure in which a compressive force is applied uniformly to the entire electrode plate, and the current collecting property of the positive electrode plate is reduced due to a structural change in the charging and discharging process of nickel oxyhydroxide. It is considered that the suppression was the reason. However, even if the batteries are prismatic, the batteries A and B according to the present invention exhibit substantially the same cycle life characteristics as the conventional cylindrical battery D. This is considered to be due to the fact that, even in the case of a prismatic battery, the pressing force on the positive electrode plate was made stronger and more uniform by forming the electrode group into a laminated structure.

Table 1 shows that 100 batteries A and B according to the present invention were produced and subjected to a charge / discharge test.
The number of batteries in which an internal short circuit occurred during 100 cycles has been shown.

[Table 1]

From the results shown in Table 1, the number of short-circuits generated in the battery B is significantly smaller than that in the battery A. This is presumed to be due to the fact that the internal short-circuit phenomenon on the side surface of the electrode plate was suppressed by wrapping the electrode plate in an envelope shape with the separator.

The excellent characteristics of the non-aqueous electrolyte battery according to the present invention as described above are obtained by stacking electrode plates in a rectangular non-aqueous electrolyte battery using nickel oxyhydroxide as a positive electrode active material. It is a thing.

[0030]

The nonaqueous electrolyte battery according to the present invention is selected from the group consisting of nickel oxyhydroxide, nickel oxyhydroxide containing lithium, a derivative of nickel oxyhydroxide and a derivative of nickel oxyhydroxide containing lithium. At least one or more positive electrode active materials are provided, the battery case is a rectangular parallelepiped type or a cubic type, and an electrode plate group is stacked, and the separator encloses either the positive electrode plate or the negative electrode plate. It is characterized by. Here, the “derivative of nickel oxyhydroxide and the derivative of nickel oxyhydroxide containing lithium” are “nickel oxyhydroxide containing any different element or nickel oxyhydroxide containing any different element and lithium” Means

As described above, in the nonaqueous electrolyte battery according to the present invention, the improvement of the cycle life performance of nickel oxyhydroxide, which has been a conventional problem, can be achieved. Therefore, a high-performance non-aqueous electrolyte battery having a high capacity and a long life can be provided. Therefore, the industrial value of the present invention is extremely large.

[Brief description of the drawings]

FIG. 1 is a diagram showing a method of laminating an electrode group of a battery A according to the present invention, and a simplified exploded perspective view of the battery.

FIG. 2 is a diagram showing a method of laminating an electrode group of a battery B according to the present invention, and a simple exploded perspective view of the battery.

FIG. 3 is a simplified exploded perspective view of a conventional battery C.

FIG. 4 is a simple sectional view of a battery D according to a conventional example.

FIG. 5 is a diagram showing a change in discharge capacity of batteries A and B according to the present invention and conventional batteries C and D as charging / discharging cycles progress.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Negative electrode plate 1a ... Negative electrode plate tab part 2 ... Positive electrode plate 2a ... Positive electrode plate tab part 3 ... Separator 4 ... Battery case 5 ... Lid 6 ... Safety valve 7 ... Insulating plate 11 ... Negative electrode terminal 12 ... Positive electrode plate surrounded by a separator 21 ... Positive electrode terminal 22 ... Positive electrode lead

Claims (2)

[Claims] At least one positive electrode active material selected from the group consisting of nickel oxyhydroxide, nickel oxyhydroxide containing lithium, a derivative of nickel oxyhydroxide and a derivative of nickel oxyhydroxide containing lithium. Equipped, the battery case is a rectangular parallelepiped type or a cube type,
A non-aqueous electrolyte battery comprising a stack of electrode plates. 2. The non-aqueous electrolyte battery according to claim 1, wherein one of the positive electrode plate and the negative electrode plate is wrapped with a separator.