JP2017168359A - Electrode for nonaqueous electrolyte battery, nonaqueous electrolyte battery including the same, and battery pack - Google Patents

Abstract

Provided are an electrode for a non-aqueous electrolyte battery having an active material layer and a current collector having sufficient binding properties and exhibiting high charge-discharge cycle characteristics, a non-aqueous electrolyte battery including the electrode, and a battery pack. An electrode for a non-aqueous electrolyte battery according to an embodiment includes a current collector and an active material layer formed on the current collector and containing an active material. The current collector has a base made of copper or a copper alloy, and a coating covering the surface of the base and made of an oxide and a carbonate of the copper or the copper alloy. The substrate made of the copper or the copper alloy has a maximum peak half-width of 930 eV to 938 eV of 2 eV to 5 eV in X-ray photoelectron spectroscopy. [Selection diagram] Figure 1

Description

  Embodiments described herein relate generally to a nonaqueous electrolyte battery electrode, a nonaqueous electrolyte battery including the electrode, and a battery pack.

  In recent years, mobile electronic devices have become widespread. Further, as these devices become more sophisticated, there is a demand for higher output and higher energy density of secondary batteries provided in these devices. Secondary batteries are also expected to be deployed in vehicles such as electric vehicles (EVs) for the purpose of environmental protection and alternative energy for oil. And as a secondary battery, the alkaline secondary battery (Ni-MH battery), the nonaqueous electrolyte secondary battery (lithium ion secondary battery) using the lithium compound, etc. are put into practical use.

  An electrode used for a nonaqueous electrolyte battery includes a current collector and an active material layer formed on the current collector. The active material layer includes an active material and a binder. Binders are required to have properties such as active materials, binding properties between the active material and the current collector, and electrochemical stability. Furthermore, in order to increase the capacity of the battery, the binder is required to satisfy these characteristics with a small addition amount. In the binder, a polar element such as a highly polar element such as fluorine or a carbonyl group typified by a ketone or an ester or a carboxyl group typified by a carboxylic acid or a salt thereof is often introduced into the structure. These highly polar elements or polar groups have effects such as increasing the solubility in polar solvents such as N-methyl-2-pyrrolidone (NMP), water, and the like. Further, these highly polar elements or polar groups greatly affect the binding force of the active material and current collector to the copper foil surface.

Usually, a Cu ₂ O film is formed on a copper foil after molding, and the film thickness increases logarithmically with standing time. It is considered that the Cu ₂ O film on the surface of the copper foil and the carbonyl group or carboxyl group are bound by electrostatic force. One of the characteristics required for the copper foil used as the current collector is its binding property with the active material layer. The binding property of the current collector to the active material layer greatly affects the cycle characteristics of the secondary battery. The active material layer inferior in binding property to the surface of the copper foil is peeled off and dropped from the copper foil when the copper foil is sized, bent or wound. Therefore, the target performance cannot be obtained, and the durability and life may be reduced. Further, if the thickness of the active material layer is non-uniform, lithium is deposited at a portion where the thickness of the active material layer is non-uniform, and dendrites are generated. Thereby, it becomes easy to produce a short circuit and it is difficult to charge a battery in a short time. As a general method for improving the binding property between the copper foil and the active material layer, there is a method in which the surface of the copper foil is roughened and physically improved. However, also in this case, since the binding is caused by electrostatic force between the oxidized copper foil surface (Cu ₂ O) and the polar group of the binder, the binding property is insufficient, and there is a problem in the charge / discharge cycle characteristics. .

JP 2012-94354 A Japanese Patent Laid-Open No. 2008-60060

  The problem to be solved by the present invention is that the active material layer and the current collector have sufficient binding properties and exhibit high charge / discharge cycle characteristics, a non-aqueous electrolyte battery electrode, and a non-aqueous electrolyte battery including the same It is to provide a battery pack.

The electrode for a nonaqueous electrolyte battery of the embodiment includes a current collector and an active material layer formed on the current collector and containing an active material.
The current collector has a base made of copper or a copper alloy and a film made of an oxide and a carbonate of the copper or the copper alloy that covers the surface of the base.
The half-width of the maximum peak of 930 eV to 938 eV is 2 eV to 5 eV in the base made of copper or the copper alloy by X-ray photoelectron spectroscopy (XPS).

It is sectional drawing which shows schematic structure of the electrode for nonaqueous electrolyte batteries which concerns on 1st Embodiment. It is a schematic diagram which shows the nonaqueous electrolyte battery which concerns on 2nd Embodiment. It is a schematic diagram which shows the nonaqueous electrolyte battery which concerns on 2nd Embodiment. It is a schematic diagram which shows the nonaqueous electrolyte battery which concerns on 2nd Embodiment. It is a schematic diagram which shows the nonaqueous electrolyte battery which concerns on 2nd Embodiment. It is a schematic perspective view which shows the battery pack which concerns on 3rd Embodiment. It is a schematic diagram which shows the battery pack which concerns on 3rd Embodiment. It is a spectrum which shows the result of the XPS measurement in Examples 1 and 2 and Comparative Examples 1 and 2.

  Hereinafter, an electrode for a nonaqueous electrolyte battery, a nonaqueous electrolyte battery including the electrode, and a battery pack according to the embodiment will be described with reference to the drawings.

(First embodiment)
In the first embodiment, a non-aqueous electrolyte battery electrode (hereinafter, abbreviated as “electrode”) including a current collector and an active material layer containing an active material formed on the current collector. Is provided).

Hereinafter, the electrode for a nonaqueous electrolyte battery according to the present embodiment will be described in more detail with reference to FIG.
FIG. 1 is a cross-sectional view showing a schematic configuration of a nonaqueous electrolyte battery electrode according to the present embodiment.
As shown in FIG. 1, the nonaqueous electrolyte battery electrode 10 according to the present embodiment includes a sheet-like current collector 11 and an active material layer 12. This nonaqueous electrolyte battery electrode 10 is used, for example, as a negative electrode of a nonaqueous electrolyte battery to be described later.
The active material layer 12 is formed on at least one surface 11a of the current collector 11, and includes an electrode material for a nonaqueous electrolyte battery containing an active material (hereinafter also abbreviated as “electrode material”), a carbonyl group, It is a layer containing a conductive material and a binder (binder) composed of at least one of polymers containing a carboxyl group and a salt thereof as a structural unit. That is, the active material layer 12 is a layer in which an electrode material is supported on at least one surface 11 a of the current collector 11.
The binder fills a gap between the electrode materials constituting the active material layer 12, binds the electrode materials or the electrode material and the conductive agent, and joins the current collector 11 and the active material layer 12. . The conductive agent is an optional component. Note that the active material layer 12 may also be formed on the other surface 11 b of the current collector 11.

  The current collector 11 is a conductive member that binds to the active material layer 12. As the current collector 11, a copper foil having a porous structure or a non-porous copper foil is used. These copper foils are composed of a base made of copper or a copper alloy and a coating made of an oxide and carbonate of copper or a copper alloy covering the surface of the base. A substrate made of copper or a copper alloy has a half-width of a maximum peak of 930 eV to 938 eV of 2 eV to 5 eV in X-ray photoelectron spectroscopy (XPS).

The method of X-ray photoelectron spectroscopy (XPS) in this embodiment is as follows.
X-ray photoelectron spectrometer (trade name: Quantum-2000, manufactured by PHI)
X-ray source / output / analysis region: single crystal spectrum AlKα ray / 40 W / diameter 200 μm
Pass Energy: Wide Scan-187.85 eV (1.60 eV / Step), Narrow Scan-58.70 eV (0.125 eV / Step)
Charge neutralizing gun: used for both Ar ⁺ and e ⁻ Geometry: θ = 45 ° (θ: angle between sample surface and detector)
Under this condition, the full width at half maximum is calculated from the XPS spectrum of Cu _2p , but the measurement may be performed under the same conditions as the above measurement conditions.

As the copper foil, electrolytic copper foil, rolled copper foil, electrolytic copper alloy foil, rolled copper alloy foil or the like is used.
These copper foils usually have a copper oxide (Cu ₂ O) film formed on the outermost surface. When only the copper oxide film is formed, in XPS measurement under the above measurement conditions, a peak derived from Cu _2p is observed at 933 eV, and the half-value width is a sharp peak of about 1.6 eV.
A surface treatment is performed in which the copper foil is stored for 1 week in an environment of humidity 10% to 100%, preferably 50% to 100%, temperature 45 ° C to 100 ° C, preferably 60 ° C to 80 ° C. Thereafter, when XPS measurement is performed on the surface, a peak starts to appear at about 935 eV on the high energy side of 933 eV, and becomes a broad peak in the range of 930 eV to 938 eV. This peak of about 935 eV is a peak derived from a copper carbonate (CuCO ₃ ) salt.

The surface treatment can be performed in an air atmosphere, but can be performed more quickly when stored in an atmosphere having a higher carbonic acid (CO ₂ ) concentration than the air atmosphere. However, even if the carbonate film concentration is increased, if there is no water, a film (copper carbonate film) made of copper carbonate (copper carbonate: CuCO ₃ ) is not formed on the surface of the copper foil. Copper carbonate (CuCO ₃ ) is strongly bound to a carbonyl group and a carboxyl group. The bond is not an electrostatic force generated between copper oxide (CuO ₂ ) but hydrogen bonding between O of copper carbonate (CuCO ₃ ) and OH of carboxyl group, or C and carbonyl group of copper carbonate. Or by covalent bonding with C of the carboxyl group. Therefore, when a polymer containing a carbonyl group, a carboxyl group or a salt thereof as a structural unit is used as a binder, high binding properties can be obtained, and cycle characteristics are improved. Further, when the surface treatment is performed for a longer time, the copper carbonate coating becomes thicker.

The thickness of the copper carbonate coating is preferably 0.5 nm or more, and more preferably 0.5 nm or more and 5 nm or less.
When the thickness of the copper carbonate film exceeds 5 nm, the peak at 933 eV disappears and becomes a peak only at 935 eV, and the full width at half maximum of the maximum peak at 930 eV to 938 eV is smaller than 2 eV.

  Copper carbonate is commonly called patina, and its physical strength is weak. Therefore, if the copper carbonate film is too thick, the copper foil strength is weakened. Moreover, when the copper carbonate coating becomes thick, the resistance of the copper foil increases. In addition, when the copper carbonate coating becomes thick and covers the entire surface of the copper foil, and the entire surface of the copper foil is covalently bonded to the binder, the copper foil cannot follow the expansion and contraction of the active material due to charge and discharge. As a result, the covalent bond between the surface of the copper foil and the binder is cut, and the active material layer is peeled off from the copper foil, or the copper foil and the active material layer are cracked. For this reason, by leaving an oxide that binds to the active material layer with a weak electrostatic force on the surface of the copper foil, the displacement of the copper foil and the active material layer due to volume expansion and contraction is alleviated, but the active material layer and the copper The binding power of the foil can be maintained.

  As described above, the copper foil covered with the oxide or carbonate has a high binding force between the carbonyl group and the carboxyl group of the binder, and is flexible to the expansion and contraction of the active material. Therefore, the copper foil is also suitable as an active material for a material having a large volume expansion / contraction due to charge / discharge, for example, a negative electrode active material containing Si.

  The thickness of the active material layer 12 is preferably 10 μm or more and 150 μm or less, and more preferably 10 μm or more and 100 μm or less. Therefore, when the active material layer 12 is formed on the one surface 11a and the other surface 11b of the current collector 11, the total thickness of the active material layer 12 is 20 μm or more and 300 μm or less.

The electrode material included in the active material layer 12 includes at least one active material selected from the group consisting of silicon particles, silicon oxide particles, silicon-containing alloy particles, tin particles, tin oxide particles, and tin-containing alloy particles. And a carbonaceous material.
The silicon oxide in this embodiment is represented by SiO _x (0 <x ≦ 2). In the present embodiment, the electrode material is preferably a composite in which composite particles composed of silicon particles and silicon oxide particles are dispersed in a carbonaceous material.

  When the active material is composite particles composed of silicon particles and silicon oxide particles, the composite includes the composite particles and a carbonaceous material. More specifically, the composite has a structure in which a plurality of composite particles are coated with a carbonaceous material. The composite may have a structure in which one composite particle is coated with a carbonaceous material. Further, a part of the composite particles may be exposed to the outside of the composite.

  The composite particles may contain a composite oxide composed of lithium and silicon particles.

The composite particles are preferably as fine as possible because volume changes occur each time lithium insertion and extraction are repeated.
The average primary particle size of the composite particles is preferably 5 nm or more and 500 nm or less.

In this embodiment, the average primary particle diameter of the composite particles is defined as that measured by the following measurement method.
In order to observe the fine structure in the active material layer, a part of the active material layer is processed into a thin piece, and the observation part is processed further thinly using an ion milling device or the like. The inside of the composite constituting the active material layer is observed at a magnification of 200,000 times or more (from about 20,000 times in the case of silicon oxide) with a transmission electron microscope (TEM). Then, at least 10 or more particles on the diagonal line of the visual field are selected, the major axis and minor axis are measured, and the average value obtained by averaging the major axis and minor axis is defined as the average primary particle diameter.

The carbonaceous material is preferably an amorphous carbon phase. The carbonaceous material will be described later.
The carbonaceous material may contain a conductive agent. As the conductive agent, carbon materials such as highly crystalline graphite, carbon nanofibers, and carbon nanotubes, and fine particles such as acetylene black are preferably used.
The carbonaceous material may contain fine pores of about 10 nm to 1 μm.

  As the binder, at least one kind of polymer including a carbonyl group, a carboxyl group, and a salt thereof as a structural unit is used. Specifically, it is at least one selected from aldehydes, ketones, carboxylic acids, carboxylic acid salts, esters, amides, acid anhydrides, and the like. These include, for example, polyvinyl methyl ketone, polyacrylic acid, sodium polyacrylate, CMC (carboxymethylcellulose), alginic acid, polyester, polymethyl methacrylate, polyamide (nylon 6, nylon 66, etc.), maleic anhydride-vinyl acetate, Maleic anhydride-styrene or the like can be used. These polymers can be used alone or in combination of a plurality of elements. Preferably, sodium polyacrylate is used.

  Next, a method for manufacturing the electrode 10 will be described.

(Composite processing)
The active material particles are mixed with an organic material, and the mixture is subjected to a carbonization heat treatment, whereby the active material particles and the organic material are combined to prepare a composite including the active material particles and the organic material. At this time, the above-mentioned conductive agent may be added.
As the organic material, at least one selected from the group consisting of carbon materials such as graphite, coke, low-temperature calcined charcoal, pitch, and carbon precursors is used. A material that is melted by heating, such as pitch, is not easily melted during mechanical milling and cannot be easily combined. Therefore, it is preferable to use a non-melting material such as graphite or coke as the organic material.

  A method of combining active material particles and an organic material by mixing and stirring in a liquid phase will be described. For the mixing and stirring treatment, for example, various stirring devices, a ball mill, a bead mill device, and the like are used. The mixing and stirring treatment may be performed with only one type of these devices, or may be performed using a combination of two or more types.

The composite of the active material particles, the organic material and the conductive agent is preferably performed by liquid phase mixing in a dispersion medium in order to disperse these materials more uniformly.
As the dispersion medium, an organic solvent, water, or the like is used, but it is preferable to use a liquid having excellent affinity with the active material particles and the organic material. Examples of such a dispersion medium include N-methyl-2-pyrrolidone (NMP), dimethylacetamide, dimethylformamide, and dimethyl sulfoxide.

  As a carbon precursor which is a kind of organic material, in order to uniformly mix with active material particles, a carbon precursor that is soluble in a liquid or a dispersion medium in a mixing stage is preferable. Or it is more preferable that it is an oligomer. Examples of the carbon precursor include furan resin, xylene resin, ketone resin, amino resin, melamine resin, urea resin, aniline resin, urethane resin, polyimide resin, polyester resin, phenol resin, resole resin, polyvinyl alcohol, and sucrose. Organic materials are mentioned.

  The above materials are mixed in a liquid phase, and the mixture is solidified or dried to produce a composite containing active material particles and an organic material, and then the composite is carbonized and fired to obtain active material particles, Forms a complex with carbonaceous material.

(Carbonization firing process)
The carbonization firing of the composite is performed in an inert atmosphere such as argon (Ar). The atmosphere at the time of carbonization firing of the composite is not limited to an inert atmosphere, and may be a mixed atmosphere such as argon containing hydrogen.
The temperature for carbonizing and firing the composite is appropriately adjusted according to the thermal decomposition temperature of the organic material contained in the composite, but is preferably 700 ° C. or higher and 1200 ° C. or lower.
If the temperature for carbonization and firing exceeds 1200 ° C., the siliconization reaction by the silicon-based particles and the organic material proceeds more than necessary, which is not preferable because the charge / discharge capacity is greatly reduced.
The firing time is preferably 10 minutes to 12 hours.

The electrode material in this embodiment can be obtained by the synthesis method as described above.
The product (electrode material) after the carbonization firing may be adjusted to a predetermined range in particle size, specific surface area, etc. using various mills, pulverizers, grinders and the like.
By using such an electrode material, the initial discharge capacity and the initial charge / discharge efficiency can be increased, and a nonaqueous electrolyte battery excellent in energy density can be realized.

(Formation of active material layer)
The electrode 10 described above is manufactured using the electrode material manufactured by the method described above.
First, a slurry is prepared by suspending an electrode material and a binder in the solvent. Here, if necessary, a conductive agent is added to prepare a slurry.
The mixing ratio of the electrode material, the binder, and the conductive agent in the slurry is preferably 40 to 95: 2 to 25: 0 to 50 by mass ratio.

Next, the slurry is applied to at least one surface 11a of the current collector 11 and dried to form a coating film containing an electrode material.
Thereafter, the active material layer 12 is formed by rolling the coating film formed on the current collector 11.

In addition, a mixture containing an active material, a conductive agent, and a binder is formed into a pellet, and the pellet-like mixture is disposed on at least one surface 11 a of the current collector 11 to form an active material layer 12. May be.
Thus, the electrode 10 is obtained.

  According to the nonaqueous electrolyte battery electrode 10 according to the present embodiment, the current collector 11 includes a base made of copper or a copper alloy, and covers the surface of the base, and is made of an oxide and carbonate of copper or copper alloy. The base made of copper or a copper alloy having a maximum half-value width of 930 eV to 938 eV by X-ray photoelectron spectroscopy (XPS) is 2 eV to 5 eV. Thereby, the electrode for nonaqueous electrolyte batteries which the active material layer 12 and the electrical power collector 11 have sufficient binding property, and shows a high charging / discharging cycle characteristic is obtained.

(Second Embodiment)
In the second embodiment, a nonaqueous electrolyte battery including a negative electrode including the electrode according to the first embodiment, a positive electrode, a nonaqueous electrolyte, a separator, and an exterior material is provided.
More specifically, the nonaqueous electrolyte battery according to the present embodiment includes an exterior material, a positive electrode accommodated in the exterior material, and a spatially separated from the positive electrode in the exterior material, and is accommodated via a separator. And a non-aqueous electrolyte filled in the exterior material.

  Hereinafter, as the nonaqueous electrolyte battery according to this embodiment, a negative electrode, a positive electrode, a nonaqueous electrolyte, a separator, and an exterior material that are constituent members of the nonaqueous electrolyte battery will be described in detail.

(1) Negative electrode As the negative electrode, the electrode according to the first embodiment described above is used.

(2) Positive electrode The positive electrode includes a positive electrode current collector and a positive electrode active material layer formed on one or both surfaces of the positive electrode current collector and including a positive electrode active material, a conductive agent, and a binder. The conductive agent and the binder (binder) are optional components.

The positive electrode active material is not particularly limited as long as it is a positive electrode active material used for a nonaqueous electrolyte battery. For example, a composite oxide containing lithium and a metal other than lithium, a lithium composite phosphate compound, or the like can be given.
Examples of the metal other than lithium contained in the composite oxide containing lithium and a metal other than lithium include at least one selected from the group consisting of Fe, Ni, Co, Mn, V, Al, and Cr.

Examples of the composite oxide containing Mn in addition to lithium include LiMn ₂ O ₄ , Li _{(1 + x)} Mn _(2-xy) M _y O _z (where M is selected from the group consisting of Ni, Co, and Fe) At least one of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1.1, 3.9 ≦ z ≦ 4.1) is used.
Examples of composite oxides containing Ni in addition to lithium include Li (Ni _x M _y ) O ₂ (where M is at least one selected from Co and Al, x + y = 1, 0 <x ≦ 1, 0 ≦ y <1).

Examples of the composite oxide containing V or Cr in addition to lithium include LiVO ₂ and LiCrO ₂ .
Examples of the lithium composite phosphate compound include LiCoPO ₄ , LiMnPO ₄ , LiFePO ₄ or Li (Fe _x M _y ) PO ₄ (where M is at least one selected from Co and Mn, x + y = 1, 0 < x <1), Li (Co _x Mn _y ) PO ₄ (wherein M is at least one selected from Fe and Mn, x + y = 1, 0 <x <1). It is done.

Among these, a positive electrode active material having a charge end voltage of 4.0 V or higher with respect to Li / Li ⁺ is preferable because the effect of the present embodiment is large.
Specific examples of the composite oxide containing Mn in addition to lithium include LiMn _1.5 Ni _0.5 O ₄ , LiMn _1.5 Co _0.5 O ₄ , LiMnFeO ₄ , LiMn _1.5 Fe _0.5 O. ₄ , LiMnCoO ₄ , Li (Ni _1/3 Co _1/3 Mn _1/3 ) O ₂ , Li (Ni _5/10 Co _2/10 Mn _3/10 ) O ₂ , Li (Ni _6/10 Co _{2 / 10} Mn _2/10 ) O ₂ , Li (Ni _8/10 Co _1/10 Mn _1/10 ) O _{2 and the} like.
Specific examples of the composite oxide containing Ni in addition to lithium include LiNiO ₂ , LiCo _0.5 Ni _0.5 O ₂ , LiNi _0.9 Al _0.1 O ₂ , and LiNi _0.8 Co _0.1 Al. _0.1 O ₂ etc. are mentioned.

Furthermore, a positive electrode active material having a charge end voltage of 4.8 V or higher with respect to Li / Li ⁺ is preferable because the effect of the present embodiment is great.
Specific examples of the positive electrode active material include LiMn _1.5 Ni _0.5 O ₄ , LiMn _1.5 Co _0.5 O ₄ , LiMn _1.5 Fe _0.5 O ₄ , LiMnCoO ₄ , and LiMnFeO. _{4, Li (Co x Mn y} ) PO 4 ( where, M is at least one selected from Fe and Mn, x + y = 1,0 < x <1) , and the like.

The shape of the positive electrode active material is preferably particulate. The average primary particle diameter of the particulate positive electrode active material is preferably 1 nm to 100 μm, and more preferably 10 nm to 30 μm.
The specific surface area of the particulate positive electrode active material ^is preferably 0.1m ² / g~10m 2 / g.

  A positive electrode active material may be used individually by 1 type, and may mix and use 2 or more types. The positive electrode active material may be mixed with an organic material active material such as a conductive polymer material or a disulfide polymer material.

  The conductive agent is not particularly limited as long as it is a conductive material and does not dissolve during charging. Examples of the conductive agent include carbon materials such as acetylene black, carbon black, and graphite, metal powder materials selected from aluminum and titanium, conductive ceramic materials, and conductive glass materials.

  As the binder, a fluororesin is preferably used. Among these, a fluororesin mainly containing at least one monomer selected from the group consisting of vinyl fluoride, vinylidene fluoride, chlorofluoroethylene, hexafluoropropene, and trifluorochloroethylene is preferable. Further, the fluororesin is more preferably a fluororesin containing at least one monomer selected from the group consisting of acrylic acid, sodium acrylate, lithium acrylate, and acrylate ester.

  The mixing ratio of the positive electrode active material, the conductive agent and the binder in the positive electrode active material layer is 80% by mass to 95% by mass for the positive electrode active material, 3% by mass to 18% by mass for the conductive agent, and 2% by mass for the binder. It is preferably 7% by mass.

  The positive electrode current collector is a conductive member that binds to the positive electrode active material layer. As the positive electrode current collector, a conductive substrate having a porous structure or a non-porous conductive substrate is used. The positive electrode current collector is preferably an aluminum foil or an aluminum alloy foil containing at least one element selected from the group consisting of Mg, Ti, Zn, Fe, Cu and Si.

  The positive electrode current collector is a conductive member that binds to the positive electrode active material layer. As the positive electrode current collector, a conductive substrate having a porous structure or a non-porous conductive substrate is used.

Next, the manufacturing method of a positive electrode is demonstrated.
First, a positive electrode active material, a conductive agent, and a binder are suspended in a commonly used solvent to prepare a slurry.
Next, the slurry is applied onto a positive electrode current collector, dried to form a positive electrode active material layer, and then subjected to pressing to obtain a positive electrode.
In addition, the positive electrode may be produced by forming a positive electrode active material, a binder, and a conductive agent blended as necessary into a pellet shape to form a positive electrode active material layer, which is disposed on the positive electrode current collector. .

(3) Non-aqueous electrolyte As the non-aqueous electrolyte, a non-aqueous electrolyte, an electrolyte-impregnated polymer electrolyte, a polymer electrolyte, or an inorganic solid electrolyte is used.
The non-aqueous electrolyte is a liquid electrolyte prepared by dissolving an electrolyte in a non-aqueous solvent (organic solvent), and is held in the voids in the electrode group.

Examples of the non-aqueous solvent include ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (MEC), diethyl carbonate (DEC), dimethyl carbonate (DMC), γ-butyrolactone (GBL), and γ-valerolactone. , Α-acetyl-γ-butyrolactone, α-methyl-γ-butyrolactone, methyl acetate, ethyl acetate, methyl propionate, ethyl butyrate, butyl acetate, n-propyl acetate, isobutyl propionate, benzyl acetate, etc. It is done. Among these, ethylene carbonate, propylene carbonate, ethyl methyl carbonate, and γ-butyrolactone are preferable.
These nonaqueous solvents may be used alone or in combination of two or more.

When γ-butyrolactone or propylene carbonate is used as the main component, chain carbonates such as diethyl carbonate, dimethyl carbonate, and ethyl methyl carbonate may be added for the purpose of reducing the viscosity. Moreover, you may add cyclic carbonates, such as ethylene carbonate, in order to raise a dielectric constant.
When the non-aqueous solvent contains an aliphatic carboxylic acid ester, from the viewpoint of gas generation, the content of the aliphatic carboxylic acid ester is preferably 30% by mass or less, and 20% by mass or less of the entire non-aqueous solvent. It is more preferable.

  As the nonaqueous solvent used in the present embodiment, for example, those having the following composition are preferable.

<Nonaqueous solvent 1>
100 volume% non-aqueous solvent consisting of 5 to 50 volume% ethylene carbonate and 50 to 95 volume% ethyl methyl carbonate.

<Nonaqueous solvent 2>
100 volume% non-aqueous solvent consisting of ethylene carbonate 5 volume% to 50 volume% and diethyl carbonate 50 volume% to 95 volume%.

<Nonaqueous solvent 3>
100 volume% non-aqueous solvent consisting of 20 volume% to 60 volume% of propylene carbonate and 40 volume% to 80 volume% of ethyl methyl carbonate.

<Nonaqueous solvent 4>
100 volume% non-aqueous solvent consisting of 20 volume% to 60 volume% of propylene carbonate and 40 volume% to 80 volume% of diethyl carbonate.

<Nonaqueous solvent 5>
A nonaqueous solvent of 100 volume% in total consisting of 5 volume% to 50 volume% of ethylene carbonate, 50 volume% to 100 volume% of propylene carbonate, and 0 volume% to 50 volume% of γ-butyrolactone.

  From the viewpoint of further improving the effect of suppressing gas generation, it is preferable that at least one selected from the group consisting of a carbonate ester-based additive and a sulfur compound-based additive is added to the nonaqueous electrolyte.

The carbonate ester-based additive has an effect of reducing gases such as H ₂ and CH ₄ generated on the negative electrode surface due to film formation or the like.
The sulfur compound-based additive has an effect of reducing gas such as CO ₂ generated on the surface of the positive electrode due to film formation or the like.

  Examples of the carbonate-based additive include vinylene carbonate, phenylethylene carbonate, phenyl vinylene carbonate, diphenyl vinylene carbonate, trifluoropropylene carbonate, chloroethylene carbonate, methoxypropylene carbonate, vinylethylene carbonate, catechol carbonate, tetrahydrofuran carbonate, diphenyl carbonate , Diethyl dicarbonate (diethyl dicarbonate) and the like. Among these, vinylene carbonate and phenyl vinylene carbonate are preferable, and vinylene carbonate is particularly preferable because the effect of reducing the gas generated on the negative electrode surface is great. These carbonic acid ester-based additives may be used alone or in combination of two or more.

  Examples of the sulfur compound-based additive include ethylene sulfite, ethylene trithiocarbonate, vinylene trithiocarbonate, catechol sulfite, tetrahydrofuran sulfite, sulfolane, 3-methylsulfolane, sulfolene, propane sultone, and 1,4-butane sultone. Etc. Among these, propane sultone, sulfolane, ethylene sulfite, and catechol sulfite are preferable, and propane sultone is particularly preferable because the effect of reducing the gas generated on the positive electrode surface is great. One of these sulfur compound-based additives may be used alone, or two or more thereof may be used in combination.

The addition rate with respect to 100 parts by mass of at least one non-aqueous electrolyte selected from the group consisting of a carbonate ester-based additive and a sulfur compound-based additive is preferably 0.1 parts by mass to 10 parts by mass in total. It is more preferable that it is 0.5 mass part-5 mass parts.
When the addition rate is less than 0.1 parts by mass, the effect of suppressing the generation of gas is not improved so much. On the other hand, when the addition rate exceeds 10 parts by mass, the film formed on the electrode becomes too thick, and the discharge characteristics deteriorate.

  When a carbonate ester-based additive and a sulfur compound-based additive are used in combination, the blending ratio (carbonate ester-based additive: sulfur compound-based additive) is preferably 1: 9 to 9: 1 by mass ratio. . If it does in this way, the effect of a carbonate ester system additive and a sulfur compound system additive can be acquired with sufficient balance.

The addition rate of the carbonate ester-based additive with respect to 100 parts by mass of the nonaqueous electrolyte is preferably 0.1 parts by mass to 10 parts by mass, and more preferably 0.5 parts by mass to 5 parts by mass.
When the addition rate is less than 0.1 parts by mass, the effect of reducing the amount of gas generated in the negative electrode is reduced. On the other hand, when the addition rate exceeds 10 parts by mass, the film formed on the negative electrode becomes too thick, and the discharge characteristics deteriorate.

The addition ratio of the sulfur compound-based additive with respect to 100 parts by mass of the nonaqueous electrolyte is preferably 0.1 part by mass to 10 parts by mass, and more preferably 0.5 part by mass to 5 parts by mass.
When the addition rate is less than 0.1 parts by mass, the effect of reducing the amount of gas generated at the positive electrode is reduced. On the other hand, when the addition rate exceeds 10 parts by mass, the film formed on the positive electrode becomes too thick and the discharge characteristics are deteriorated.

As the electrolyte contained in the nonaqueous electrolyte, an alkali salt is used, and among the alkali salts, a lithium salt is preferably used.
Examples of the lithium salt include LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) ₃ , LiPF ₄ (CF ₃ SO _2). ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiPF ₃ (CF ₃ SO ₂ ) ₃ , LiPF ₃ (C ₂ F ₅ SO ₂ ) ₃ , LiBF ₂ (CF ₃ ) ₂ , LiBF ₂ (C _{2) F 5) 2, LiBF 2 (} CF 3 SO 2) 2, LiBF 2 (C 2 F 5 SO 2) 2, LiPF 6, LiBF 4, LiSbF 6, LiAsF 6 , and the like.

Since the above lithium salt is very excellent in thermal stability, there is little deterioration in battery characteristics during use at high temperature or after storage at high temperature, and gas generation due to thermal decomposition is also small. However, these lithium salts have a problem that they are susceptible to a decomposition reaction on the positive electrode. _{Therefore, LiPF 6, LiBF 4, LiSbF} 6 and at least one lithium salt selected from the group consisting of LiAsF _6, so it is preferably contained in the non-aqueous electrolyte. Then, these lithium salts react preferentially on the positive electrode, and a high-quality film is formed on the positive electrode. As a result, the decomposition reaction of the above compound on the positive electrode is suppressed.

(4) Separator The separator is disposed between the positive electrode and the negative electrode in order to pass lithium ions while preventing the positive electrode and the negative electrode from contacting each other and preventing a short circuit of current due to the contact between the two electrodes. . The separator is made of an insulating material.
As the separator, a separator in which the electrolyte can move between the positive electrode and the negative electrode is used. Examples of the separator include polyethylene (PE), polypropylene (PP), cellulose, a porous film containing polyvinylidene fluoride (PVdF), a synthetic resin nonwoven fabric, and a lithium ion conductive ceramic thin film. These separators may be used individually by 1 type, and may be used in combination of 2 or more type.

(5) Exterior material As the exterior material in which the positive electrode, the negative electrode, and the nonaqueous electrolyte are accommodated, a metal container or a laminate film exterior container is used.
As the metal container, a metal can made of aluminum, aluminum alloy, iron, stainless steel or the like having a square or cylindrical shape is used.
As the aluminum alloy, an alloy containing elements such as magnesium, zinc and silicon is preferable. When the aluminum alloy contains a transition metal such as iron, copper, nickel, or chromium, the content is preferably 100 ppm or less. A metal container made of an aluminum alloy has a strength that is dramatically higher than that of a metal container made of aluminum, so that the thickness of the metal container can be reduced. As a result, a non-aqueous electrolyte battery that is thin, lightweight, has high output, and has excellent heat dissipation can be realized.

  Examples of the laminate film include a multilayer film in which an aluminum foil is covered with a resin film. As the resin constituting the resin film, polymer compounds such as polypropylene (PP), polyethylene (PE), nylon, polyethylene terephthalate (PET) are used.

The present embodiment can be applied to various forms of nonaqueous electrolyte batteries such as a flat type (thin type), a square type, a cylindrical type, a coin type, and a button type.
The nonaqueous electrolyte battery according to this embodiment can further include a lead that is electrically connected to the electrode group including the positive electrode and the negative electrode. The nonaqueous electrolyte battery according to the present embodiment can include, for example, two leads. In that case, one lead is electrically connected to the positive current collecting tab, and the other lead is electrically connected to the negative current collecting tab.
The lead material is not particularly limited, and for example, the same material as the positive electrode current collector and the negative electrode current collector is used.

The nonaqueous electrolyte battery according to the present embodiment may further include a terminal that is electrically connected to the lead and drawn from the exterior material. The nonaqueous electrolyte battery according to the present embodiment can include, for example, two terminals. In that case, one terminal is connected to a lead electrically connected to the positive electrode current collector tab, and the other terminal is connected to a lead electrically connected to the negative electrode current collector tab.
The material of the terminal is not particularly limited, and for example, the same material as the positive electrode current collector and the negative electrode current collector is used.

(6) Nonaqueous Electrolyte Battery Next, a flat type nonaqueous electrolyte battery (nonaqueous electrolyte battery) 30 shown in FIGS. 2 and 3 will be described as an example of the nonaqueous electrolyte battery according to this embodiment. FIG. 2 is a schematic cross-sectional view of the flat type nonaqueous electrolyte battery 30. 3 is an enlarged cross-sectional view of a portion A shown in FIG. Each of these drawings is a schematic diagram for explaining the nonaqueous electrolyte battery according to the present embodiment, and there are places where the shape, dimensions, ratio, and the like are different from those of the actual device. The design can be changed as appropriate in consideration of known techniques.

  A non-aqueous electrolyte battery 30 shown in FIG. 2 is configured such that a flat wound electrode group 31 is housed in an exterior material 32. The packaging material 32 may be a laminate film formed in a bag shape or a metal container. In addition, the flat wound electrode group 31 is formed by winding a laminate in which the negative electrode 33, the separator 34, the positive electrode 35, and the separator 34 are laminated in this order from the outside, that is, the exterior material 32 side, and press-molding. It is formed by. As shown in FIG. 3, the negative electrode 33 located on the outermost periphery has a configuration in which a negative electrode layer 33b is formed on one surface on the inner surface side of the negative electrode current collector 33a. The negative electrode 33 other than the outermost periphery has a configuration in which the negative electrode layer 33b is formed on both surfaces of the negative electrode current collector 33a. The positive electrode 35 has a configuration in which positive electrode layers 35b are formed on both surfaces of a positive electrode current collector 35a. In addition, it may replace with the separator 34 and may use the gel-like nonaqueous electrolyte mentioned above.

  In the wound electrode group 31 shown in FIG. 2, the negative electrode terminal 36 is electrically connected to the negative electrode current collector 33 a of the outermost negative electrode 33 in the vicinity of the outer peripheral end. The positive electrode terminal 37 is electrically connected to the positive electrode current collector 35 a of the inner positive electrode 35. The negative electrode terminal 36 and the positive electrode terminal 37 are extended to the outside of the exterior material 32 or connected to a take-out electrode provided in the exterior material 32.

  When manufacturing the non-aqueous electrolyte battery 30 having a packaging material made of a laminate film, the wound electrode group 31 to which the negative electrode terminal 36 and the positive electrode terminal 37 are connected is mounted on a bag-shaped packaging material 32 having an opening. Enter. Next, a liquid non-aqueous electrolyte is injected from the opening of the exterior member 32. Further, the wound electrode group 31 and the non-aqueous electrolyte are completely sealed by heat-sealing the opening of the bag-shaped exterior member 32 with the negative electrode terminal 36 and the positive electrode terminal 37 sandwiched therebetween.

  Moreover, when manufacturing the nonaqueous electrolyte battery 30 provided with the exterior material which consists of metal containers, the wound electrode group 31 to which the negative electrode terminal 36 and the positive electrode terminal 37 were connected is inserted into the metal container which has an opening part. . Then. A liquid non-aqueous electrolyte is injected from the opening of the exterior member 32. Further, the lid is attached to the metal container to seal the opening.

  As the negative electrode terminal 36, for example, a material having electrical stability and conductivity in a range where the potential with respect to lithium is 0 V or more and 3 V or less can be used. Specifically, aluminum or an aluminum alloy containing elements such as Mg, Ti, Zn, Mn, Fe, Cu, and Si can be given. The negative electrode terminal 36 is more preferably made of the same material as the negative electrode current collector 33a in order to reduce the contact resistance with the negative electrode current collector 33a.

As the positive electrode terminal 37, a material having electrical stability and conductivity in a range where the potential with respect to lithium is 2 V or more and 4.25 V or less can be used. Specifically, aluminum or an aluminum alloy containing an element such as Mg, Ti, Zn, Mn, Fe, Cu, or Si can be given. The positive electrode terminal 37 is preferably made of the same material as the positive electrode current collector 35a in order to reduce the contact resistance with the positive electrode current collector 35a.
Hereinafter, the exterior member 32, the negative electrode 33, the positive electrode 35, the separator 30, and the nonaqueous electrolyte, which are constituent members of the nonaqueous electrolyte battery 30, will be described in detail.

(1) Exterior Material As the exterior material 32, the above exterior material is used.

(2) Negative electrode As the negative electrode 33, the electrode which concerns on the above-mentioned 1st Embodiment is used.

(3) Positive Electrode As the positive electrode 35, the above positive electrode is used.

(4) Separator As the separator 34, the above separator is used.

(5) Nonaqueous electrolyte As the nonaqueous electrolyte, the above nonaqueous electrolyte is used.

  The nonaqueous electrolyte battery according to the second embodiment is not limited to the structure shown in FIGS. 2 and 3 described above, and may be a battery having the structure shown in FIGS. 4 and 5, for example. FIG. 4 is a partially cutaway perspective view schematically showing another flat type nonaqueous electrolyte battery according to the second embodiment, and FIG. 5 is an enlarged cross-sectional view of a portion B in FIG.

  The non-aqueous electrolyte battery 40 shown in FIGS. 4 and 5 is configured such that a laminated electrode group 41 is accommodated in an exterior material 42. As shown in FIG. 5, the stacked electrode group 41 has a structure in which positive electrodes 43 and negative electrodes 44 are alternately stacked with a separator 45 interposed therebetween.

  There are a plurality of positive electrodes 43, each including a positive electrode current collector 43a and a positive electrode layer 43b supported on both surfaces of the positive electrode current collector 43a. The positive electrode layer 43b contains a positive electrode active material.

  There are a plurality of negative electrodes 44, each including a negative electrode current collector 44a and a negative electrode layer 44b carried on both surfaces of the negative electrode current collector 44a. The negative electrode layer 44b contains a negative electrode material. One side of the negative electrode current collector 44 a of each negative electrode 44 protrudes from the negative electrode 44. The protruding negative electrode current collector 44 a is electrically connected to the strip-shaped negative electrode terminal 46. The tip of the strip-like negative electrode terminal 46 is drawn out from the exterior material 42 to the outside. Although not shown, the positive electrode current collector 43 a of the positive electrode 43 has a side protruding from the positive electrode 43 on the side opposite to the protruding side of the negative electrode current collector 44 a. The positive electrode current collector 43 a protruding from the positive electrode 43 is electrically connected to the belt-like positive electrode terminal 47. The front end of the strip-like positive electrode terminal 47 is located on the side opposite to the negative electrode terminal 46, and is drawn out from the side of the exterior material 42.

  The materials, compounding ratios, dimensions, etc. of the members constituting the nonaqueous electrolyte battery 40 shown in FIGS. 4 and 5 are the same as those of the components of the nonaqueous electrolyte battery 30 described in FIGS. .

According to this embodiment described above, a nonaqueous electrolyte battery can be provided.
The nonaqueous electrolyte battery according to this embodiment includes a negative electrode, a positive electrode, a nonaqueous electrolyte, a separator, and an exterior material. A negative electrode consists of the electrode for nonaqueous electrolyte batteries which concerns on the above-mentioned 1st Embodiment. Thereby, the nonaqueous electrolyte battery according to this embodiment has an excellent energy density and a long life.

(Third embodiment)
Next, the battery pack according to the third embodiment will be described in detail.
The battery pack according to the present embodiment has at least one nonaqueous electrolyte battery (that is, a single battery) according to the second embodiment as a secondary battery. When the battery pack includes a plurality of single cells, the single cells are electrically connected in series, parallel, or connected in series and parallel.
The battery pack according to the third embodiment can further include a protection circuit. The protection circuit controls charging / discharging of the nonaqueous electrolyte battery. Or the circuit contained in the apparatus (for example, an electronic device, a motor vehicle, etc.) which uses a battery pack as a power supply can also be used as a protection circuit of a battery pack.
The battery pack according to the third embodiment can further include an external terminal for energization. The external terminal for energization is for outputting the current from the nonaqueous electrolyte battery to the outside and for inputting the current to the nonaqueous electrolyte battery. In other words, when the battery pack is used as a power source, current is supplied to the outside through the external terminal for energization. Further, when charging the battery pack, a charging current (including regenerative energy of power of an automobile or the like) is supplied to the battery pack through an external terminal for energization.

With reference to FIG. 6 and FIG. 7, the battery pack 50 which concerns on this embodiment is demonstrated concretely. In the battery pack 50 shown in FIG. 7, the flat type nonaqueous electrolyte battery 30 shown in FIG. 2 is used as the single battery 51.
The plurality of single cells 51 are laminated so that the negative electrode terminal 36 and the positive electrode terminal 37 for energization extending to the outside are aligned in the same direction, and are fastened with an adhesive tape 52 to constitute an assembled battery 53. These unit cells 51 are electrically connected to each other in series as shown in FIGS.

  The printed wiring board 54 is disposed to face the side surface of the unit cell 51 from which the negative electrode terminal 36 and the positive electrode terminal 37 extend. As shown in FIG. 6, the printed wiring board 54 has a protection circuit that controls charging and discharging in order to protect the single cells 51. The printed wiring board 54 is mounted with a thermistor 55 (see FIG. 7), a protection circuit 56, and a terminal 57 for energizing external devices. An insulating plate (not shown) is attached to the surface of the printed wiring board 54 facing the assembled battery 53 in order to avoid unnecessary connection with the wiring of the assembled battery 53.

  The positive electrode side lead 58 is connected to the positive electrode terminal 37 located in the lowermost layer of the assembled battery 53, and the tip thereof is inserted into the positive electrode side connector 59 of the printed wiring board 54 and electrically connected thereto. The negative electrode side lead 60 is connected to the negative electrode terminal 36 located in the uppermost layer of the assembled battery 53, and the tip thereof is inserted into the negative electrode side connector 61 of the printed wiring board 54 and electrically connected thereto. The positive connector 59 and the negative connector 61 are connected to the protection circuit 56 through wirings 62 and 63 (see FIG. 7) formed on the printed wiring board 54.

  The thermistor 55 is used to detect the temperature of the unit cell 51 and is not shown in FIG. 6, but is provided in the vicinity of the unit cell 51 and its detection signal is transmitted to the protection circuit 56. . The protection circuit 56 can cut off the plus-side wiring 64a and the minus-side wiring 64b between the protection circuit 56 and the energization terminal 57 to the external device under a predetermined condition. Here, the predetermined condition is, for example, when the temperature detected by the thermistor 55 is equal to or higher than a predetermined temperature. Furthermore, the predetermined condition is when an overcharge, overdischarge, overcurrent, or the like of the unit cell 51 is detected. Such detection of overcharge or the like is performed for each single cell 51 or the entire single cell 51. In addition, when detecting the overcharge etc. in each single cell 51, a battery voltage may be detected, and a positive electrode potential or a negative electrode potential may be detected. In the latter case, a lithium electrode used as a reference electrode is inserted into each unit cell 51. In the case of FIG. 6 and FIG. 7, the voltage detection wiring 65 is connected to each of the single cells 51, and the detection signal is transmitted to the protection circuit 56 through these wirings 65. The protection circuit 56 can also be provided in a circuit of an external device.

  As shown in FIG. 6, protective sheets 66 made of rubber or resin are disposed on the three side surfaces of the assembled battery 53 excluding the side surfaces from which the positive electrode terminal 37 and the negative electrode terminal 36 protrude.

  The assembled battery 53 is stored in a storage container 67 together with each protective sheet 66 and the printed wiring board 54. That is, the protective sheet 66 is disposed on both the inner side surface in the long side direction and the inner side surface in the short side direction of the storage container 67, and the printed wiring board 54 is disposed on the inner side surface opposite to the protective sheet 66 in the short side direction. Be placed. The assembled battery 53 is located in a space surrounded by the protective sheet 66 and the printed wiring board 54. The lid 68 is attached to the upper surface of the storage container 67.

  For fixing the assembled battery 53, a heat shrink tape may be used in place of the adhesive tape 52. In this case, protective sheets are arranged on both side surfaces of the assembled battery, the heat shrinkable tape is circulated, and then the heat shrinkable tape is heat shrunk to bind the assembled battery.

  Here, in FIGS. 6 and 7, the configuration in which the unit cells 51 are connected in series is shown. However, in order to increase the battery capacity, the unit cells 51 may be connected in parallel or in parallel with the series connection. It is good also as a structure which combined the connection. In addition, the assembled battery packs can be further connected in series and in parallel.

According to this embodiment described above, a battery pack can be provided. The battery pack according to the present embodiment includes at least one nonaqueous electrolyte battery according to the second embodiment.
Such a battery pack has an excellent energy density and a long life.

  In addition, the aspect of a battery pack is changed suitably by a use. As a use of the battery pack according to the present embodiment, one that is required to exhibit excellent cycle characteristics when a large current is taken out is preferable. Specific examples include a power source for a digital camera and a vehicle such as a two-wheel or four-wheel hybrid electric vehicle, a two-wheel or four-wheel electric vehicle, and an assist bicycle. In particular, a battery pack using a nonaqueous electrolyte battery having excellent high temperature characteristics is suitably used for in-vehicle use. Moreover, in a vehicle equipped with a battery pack, the battery pack collects, for example, regenerative energy of the power of an automobile.

  Hereinafter, based on an Example, said embodiment is described further in detail.

<Example 1>
The copper foil was stored for 3 weeks in an air atmosphere at 60 ° C. filled with saturated steam, and the copper foil was subjected to a surface treatment.
This copper foil was subjected to XPS measurement. The measurement conditions are as follows.
X-ray photoelectron spectrometer (trade name: Quantum-2000, manufactured by PHI)
X-ray source / output / analysis region: single crystal spectrum AlKα ray / 40 W / diameter 200 μm
Pass Energy: Wide Scan-187.85 eV (1.60 eV / Step), Narrow Scan-58.70 eV (0.125 eV / Step)
Charge neutralizing gun: used for both Ar ⁺ and e ⁻ Geometry: θ = 45 ° (θ: angle between sample surface and detector)
The result of XPS measurement is shown in FIG.
From the results of FIG. 8, it was confirmed that there was a broad peak having a full width at half maximum of 3.65 eV from 930 eV to 938 eV.
A composite particle composed of Si and a carbonaceous material, graphite, and a sodium polyacrylate binder were mixed to prepare a slurry.
The compounding ratio of the composite particles and graphite in the slurry was 1.2: 0.2 by mass ratio. The blending amount of the sodium polyacrylate binder was 16% by mass of the total solid content contained in the slurry.
The slurry was applied onto a copper foil and rolled, then dried at 130 ° C., then rolled, and further dried in vacuo at 130 ° C. overnight to form an active material layer, whereby the negative electrode of Example 1 was produced. did.
Using this negative electrode, a three-electrode glass cell was produced under an argon gas atmosphere.
Lithium metal was used as the reference electrode and the positive electrode.
A glass filter was used as the separator.
As an electrolytic solution, vinylene carbonate was mixed into a mixed solvent containing ethylene carbonate (EC) and methyl ethyl carbonate (MEC) containing 1 mol / L of bistrifluoromethylsulfonylimide lithium in a volume ratio of 1: 2. The solution which melt | dissolved 1 mass% was used.
The charge / discharge test of the three-electrode glass cell was performed in the range of 0.01 V to 1.5 V under the following conditions in a thermostatic bath at 25 ° C.
(Charge / discharge test conditions)
Charging: 0.01V (CCCV)
Discharge: 1.5 V (CC)
Table 1 shows the discharge capacity retention rate after 50 cycles.

<Example 2>
The copper foil was stored for 1 week in an environment in which CO ₂ gas at 60 ° C. filled with saturated steam was blown, and the copper foil was subjected to a surface treatment.
This copper foil was subjected to XPS measurement in the same manner as in Example 1.
The result of XPS measurement is shown in FIG.
From the results of FIG. 8, it was confirmed that there was a broad peak with a half-value width of 3.63 eV at the maximum peak of 930 eV to 938 eV.
A three-electrode glass cell was produced in the same manner as in Example 1 except that this copper foil was used.
The obtained three-electrode glass cell was subjected to a charge / discharge test in the same manner as in Example 1. Table 1 shows the discharge capacity retention rate after 50 cycles.

<Comparative Example 1>
The copper foil was stored for 1 week in an air atmosphere at 25 ° C.
This copper foil was subjected to XPS measurement in the same manner as in Example 1.
The result of XPS measurement is shown in FIG.
From the results of FIG. 8, it was confirmed that there was a sharp peak with a half-value width of 1.64 eV at the maximum peak of 930 eV to 938 eV.
When an attempt was made to produce a negative electrode in the same manner as in Example 1 except that this copper foil was used, the negative electrode could not be produced.

<Comparative example 2>
The copper foil was stored for 1 week in an environment filled with carbon dioxide, excluding moisture.
This copper foil was subjected to XPS measurement in the same manner as in Example 1.
The result of XPS measurement is shown in FIG.
From the results of FIG. 8, it was confirmed that there was a sharp peak having a maximum half-value width of 930 eV to 938 eV of 1.66 eV.
A three-electrode glass cell was produced in the same manner as in Example 1 except that this copper foil was used.
The obtained three-electrode glass cell was subjected to a charge / discharge test in the same manner as in Example 1. Table 1 shows the discharge capacity retention rate after 50 cycles.

From the results shown in Table 1, in Examples 1 and 2, the discharge capacity retention after 50 cycles was 87% or more.
On the other hand, in Comparative Example 2, the discharge capacity retention rate after 50 cycles was 55%.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Electrode for nonaqueous electrolyte batteries, 11 ... Current collector, 12 ... Active material layer, 30 ... Nonaqueous electrolyte battery, 31 ... Winding electrode group, 32 ... Exterior Material: 33 ... Negative electrode, 34 ... Separator, 35 ... Positive electrode, 36 ... Negative electrode terminal, 37 ... Positive electrode terminal, 40 ... Nonaqueous electrolyte battery, 41 ... Multilayer electrode Group, 42 ... exterior material, 43 ... positive electrode, 43a ... positive electrode current collector, 44 ... negative electrode, 44a ... negative electrode current collector, 45 ... separator, 46 ... negative electrode Terminal: 47 ... Positive terminal, 50 ... Battery pack, 51 ... Single cell, 52 ... Adhesive tape, 53 ... Assembly battery, 54 ... Printed circuit board, 55 ... Thermistor , 56... Protection circuit, 57... Energization terminal, 58... Positive electrode side lead, 59. .. Negative electrode side lead, 61... Negative electrode side connector, 62... Wiring, 63... Wiring, 64 a... Plus side wiring, 64 b. ..Protective sheet, 67... Storage container, 68.

Claims (9)

A current collector, and an active material layer formed on the current collector and containing an active material,
The current collector is composed of a base made of copper or a copper alloy, and a film made of an oxide and a carbonate of the copper or the copper alloy that covers the surface of the base.
The substrate made of copper or the copper alloy is an electrode for a non-aqueous electrolyte battery in which the half-value width of the maximum peak of 930 eV to 938 eV is 2 eV to 5 eV by X-ray photoelectron spectroscopy.   The electrode for a nonaqueous electrolyte battery according to claim 1, wherein the thickness of the coating is 0.5 nm or more.   The electrode for a nonaqueous electrolyte battery according to claim 1 or 2, wherein the active material layer contains at least one kind of polymer containing a carbonyl group, a carboxyl group, and a salt thereof as a constituent unit.   The electrode for a nonaqueous electrolyte battery according to claim 3, wherein the polymer contains acrylic acid and acrylate as structural units.   The electrode for a non-aqueous electrolyte battery according to claim 4, wherein the cation constituting the acrylate is at least one selected from the group consisting of sodium, lithium and potassium. The active material consists of a silicon phase and a silicon oxide phase,
The electrode for a non-aqueous electrolyte battery according to claim 1, wherein the active material layer is a negative electrode material including composite particles composed of the silicon phase, the silicon oxide phase, and a carbon material. . Comprising a positive electrode containing a positive electrode active material, a negative electrode, and a non-aqueous electrolyte;
The said negative electrode is a nonaqueous electrolyte battery which consists of an electrode for nonaqueous electrolyte batteries of any one of Claims 1-6.   A battery pack comprising the nonaqueous electrolyte battery according to claim 7.   The battery pack according to claim 8, further comprising an external terminal for energization and a protection circuit.

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