JP2008204902A - Electrode lead, its manufacturing method, and nonaqueous electrolyte secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode lead having a structure without slit burrs, its manufacturing method and a nonaqueous electrolyte secondary battery. <P>SOLUTION: The electrode lead is used for a nonaqueous electrolyte secondary battery with an electrode lamination structure, with its edge part put under a chamfering treatment and/or a rounding treatment. For manufacturing the electrode lead, a drawn wire is rolled out, and a chamfering treatment and/or a round treatment is carried out on its edge part. The nonaqueous electrolyte secondary battery is provided with a cathode, an anode, a separator arranged between the cathode and the anode, a nonaqueous electrolyte composition, and a battery can for housing the above, and has a chamfering treatment and/or a rounding treatment made on the edge part of the electrode lead connecting the electrode and the battery can. Or, it is provided with a cathode, an anode, a separator arranged between the cathode and the anode, a nonaqueous electrolyte composition, and a laminated outer package for housing the above, and has a chamfering treatment and/or a rounding treatment made on the edge part of the electrode lead connected to the anode. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrode lead, a manufacturing method thereof, and a non-aqueous electrolyte secondary battery, and more particularly to an electrode lead excellent in stability against charge / discharge, a manufacturing method thereof, and a non-aqueous electrolyte secondary battery.

In recent years, since it is lightweight and has high potential, high capacity, high performance, long life, etc., it is a non-aqueous electrolyte secondary battery as a power source for notebook personal computers, electric mobile bodies such as electric cars and electric bicycles. For example, lithium ion secondary batteries are widely used.
Under such circumstances, in order to maintain high reliability, reduction of metallic foreign matter inside the battery is required. For example, it has been proposed to perform strong cleaning of the negative electrode can and prevent metal falling during battery manufacture.

  As shown in FIG. 1, a negative electrode lead using a conventional technique is obtained by slitting from a roll to a specified width with a cutter. For this reason, slit burrs are generated as shown in the cross-sectional view of FIG. The slit burr falls during battery assembly, becomes a metal foreign substance in the battery, causes a short circuit between the electrodes, and threatens the reliability of the battery.

Metal strips such as copper strips are widely used as lead frames for electronic parts, copper foils for lithium ion batteries, conductive layer materials for power cables, and the like. In general, the cross-sectional shape of such a metal strip is not a perfect quadrilateral shape, and sharp slit burrs are formed at the corners of the edge surface. Therefore, in copper strips used for transformer windings and electromagnetic coils, slits It was customary to chamfer the edge portion later (see, for example, Patent Document 1).
JP 2000-263314 A

  The present invention has been made in view of such problems of the prior art, and an object thereof is to provide an electrode lead having a structure without a slit burr, a manufacturing method thereof, and a nonaqueous electrolyte secondary battery. There is.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by performing chamfering and / or R processing on the edge without adopting slit processing, The present invention has been completed.

That is, the electrode lead of the present invention is an electrode lead used for a nonaqueous electrolyte secondary battery having an electrode laminate structure,
The edge is chamfered and / or rounded.

Further, the manufacturing method of the electrode lead of the present invention, in manufacturing the electrode lead,
The wire drawing is rolled, and the edge is chamfered and / or rounded.

Further, a positive electrode having a positive electrode active material capable of occluding and releasing lithium and a positive electrode current collector, a negative electrode having a negative electrode active material capable of occluding and releasing lithium and a negative electrode current collector, and between the positive electrode and the negative electrode In a non-aqueous electrolyte secondary battery comprising a disposed separator, a non-aqueous electrolyte composition, and a battery can that accommodates these,
The edge part of the electrode lead which connects an electrode and a battery can is chamfered and / or processed.

Furthermore, the non-aqueous electrolyte secondary battery of the present invention comprises a positive electrode active material capable of inserting and extracting lithium and a positive electrode having a positive electrode current collector, a negative electrode active material capable of inserting and extracting lithium and a negative electrode current collector. In a non-aqueous electrolyte secondary battery comprising a negative electrode having a separator disposed between the positive electrode and the negative electrode, a non-aqueous electrolyte composition, and a negative electrode can containing these,
The edge portion of the electrode lead connecting the negative electrode and the negative electrode can is chamfered and / or R processed.

Another non-aqueous electrolyte secondary battery of the present invention includes a positive electrode active material capable of inserting and extracting lithium and a positive electrode having a positive electrode current collector, and a negative electrode active material and negative electrode current collector capable of inserting and extracting lithium. In a non-aqueous electrolyte secondary battery comprising: a negative electrode having a separator; a separator disposed between the positive electrode and the negative electrode; a non-aqueous electrolyte composition; and a laminate exterior housing these.
The edge of the electrode lead connected to the negative electrode is chamfered and / or rounded.

  According to the present invention, since chamfering and / or R processing is performed on the edge without adopting slit processing, an electrode lead having a structure without slit burrs, a manufacturing method thereof, and a nonaqueous electrolyte secondary battery are provided. Can be provided.

  Hereinafter, the electrode lead of the present invention and the manufacturing method thereof will be described in detail. In the present specification, “%” for concentration, content, blending amount and the like represents a mass percentage unless otherwise specified.

As described above, the electrode lead of the present invention is used for a non-aqueous electrolyte secondary battery having an electrode laminated structure, and its edge is formed by either chamfering or R processing or both. .
Due to such a shape without slit burrs, burrs and edge portions do not fall during battery assembly, so that foreign metal can be prevented from entering the battery and the reliability of the battery can be improved.

Typically, for example, the negative electrode lead 30 as shown in FIG. 3 can be disposed in a shape between the outermost periphery of the laminated electrode wound in a cylindrical shape and the negative electrode can.
At this time, in the case of using the slit product manufactured by the above-described conventional method, when the electrode expands due to charging, as shown in FIG. 5 (upper figure), at the acute edge (arrow part) of the lead, It is easy to break.
On the other hand, since the electrode lead (lower figure) which is one embodiment of the present invention has an R-shaped lead edge (arrow part), electrode damage and electrode breakage are suppressed. Accordingly, current short-circuit due to electrode damage or electrode breakage can be prevented.

The electrode lead of the present invention is preferably a nickel-based lead from the viewpoint of battery characteristics and weldability.
In a lithium ion secondary battery, if a nickel-based metallic foreign matter is mixed, there is a high possibility that a large current short circuit will occur. For example, by adopting the configuration of the present invention for a nickel-based negative electrode lead, the large current short circuit is effectively made. Can be prevented.

Here, the electrode lead of the present invention described above is manufactured by a wire drawing method.
Specifically, as shown in FIG. 6, one or both of chamfering and R processing were applied to the drawn wire by rolling the drawn wire through a roll that was pressurized from above and below. A flat lead is obtained.

  As shown in FIG. 2 (right figure), the cross-sectional shape of the electrode lead obtained by such a manufacturing method is such that the end portion of the flat lead has an R shape and does not have a burr or an edge shape. For this reason, at the time of battery assembly, burrs and edge portions do not fall, and metal foreign matter can be prevented from being mixed into the battery, thereby improving reliability.

If the electrode lead has slit burrs, the diameter of the electrode must be reduced by the height of the burrs, which hinders high capacity.
On the other hand, the wire drawing method employed by the present invention can increase the diameter of the electrode as much as there is no burr in the obtained electrode lead, and the capacity can be increased accordingly.

Next, the nonaqueous electrolyte secondary battery of the present invention will be described with reference to the drawings.
As described above, the nonaqueous electrolyte secondary battery of the present invention includes the electrode lead of the present invention described above.

FIG. 3 is a partially cutaway perspective view showing an embodiment of the first nonaqueous electrolyte secondary battery of the present invention, and shows a so-called wound-type cylindrical battery.
In FIG. 3, a battery 1 includes a wound body 3 arranged around a center pin 4 (not shown) in a cylindrical battery can 2 having an open upper surface, which is an example of an exterior member. It has a configuration sealed with a lid 5.
Here, the battery can 2 is made of, for example, a nickel-plated iron can, and the wound body 3 is wound in the same manner via the wound separators 7 and 8 containing the electrolyte. And the negative electrode 10 has the structure arrange | positioned facing.

The battery lid 5 is provided with a safety valve mechanism 18 together with a heat sensitive resistor (PTC element) on the inside, and the battery lid 5 is caulked to the battery can 2 via the gasket 6. It is attached. That is, the inside of the battery can 1 is sealed by the battery can 2 and the battery lid 5.
The safety valve mechanism 18 is electrically connected to the battery lid 5 via the heat-sensitive resistance element 19, and is incorporated, for example, when the internal pressure of the battery exceeds a certain level due to internal short circuit or external heating. The disk plate is inverted and the electrical connection between the battery lid 5 and the wound body 3 is disconnected. Here, the heat-sensitive resistance element 19 prevents abnormal heat generation due to a large current by limiting the current by increasing the resistance value when the temperature rises.

4 is a cross-sectional view schematically showing a cross-sectional structure of the wound body 3 shown in FIG.
In the present embodiment, the wound body 3 has a configuration in which a strip-like (thin plate-like) positive electrode 9 and a negative electrode 10 are arranged to face each other via separators 7 and 8 containing an electrolyte, and these are wound.
A positive electrode lead (not shown) made of, for example, aluminum and a negative electrode lead 30 made of, for example, nickel are connected to the positive electrode 9 and the negative electrode 10 of the wound body 3, respectively. The positive electrode lead is welded to the safety valve mechanism 18 to be connected to the battery cover. 5, and the negative electrode lead 30 is directly welded and electrically connected to the battery can 2.

Here, the negative electrode lead 30 is obtained by rolling a drawn wire, and one or both of chamfering and R processing are applied to the edge portion.
By using such a lead, it is possible to prevent the metallic foreign matter from being mixed into the battery due to the drop of the slit burr at the time of battery assembly. In addition, when a nickel lead is used for the negative electrode, if a similar burr drop occurs, there is a high possibility of causing a large current short-circuit, but since this can be effectively prevented, the reliability of the battery is improved.

In addition, FIG. 7 shows a schematic cross-sectional view of the outer edge portion of the wound body 3 comparing before and after charging of the battery.
As is apparent from FIG. 7, in this embodiment, the diameter of the wound electrode body can be increased by the absence of the burr height of the slit burr, and the capacity can be increased. Specifically, a capacity increase of about 0.3% can be achieved. In addition, it is possible to prevent current short-circuit due to electrode damage or electrode breakage that occurs at the acute angle edge of the negative electrode lead due to electrode swelling after charging.
On the other hand, as shown in FIG. 8, the battery using the slit-type negative electrode lead cannot increase the diameter of the wound electrode body by the burr height of the slit burr. In addition, electrode damage and electrode breakage that occur at the sharp edge of the negative electrode lead due to electrode swelling after charging are likely to occur.

The positive electrode 9 is, for example, a positive electrode current collector 11 having a first main surface 11a serving as an inner surface and a second main surface 11b serving as an outer surface in a winding structure. The outer positive electrode active material layer 13 is formed on the second main surface 11b side of the layer 12, respectively.
The inner surface positive electrode active material layer 12 and the outer surface positive electrode active material layer 13 are selected and configured according to the intended battery configuration and characteristics, using materials that can be doped / undoped with lithium as described later. Is preferred. Further, it is not always necessary to provide both on the inner surface and the outer surface. The positive electrode current collector 11 can be made of, for example, aluminum, nickel, stainless steel, or the like.

Moreover, the inner surface positive electrode active material layer 12 and the outer surface positive electrode active material layer 13 include a positive electrode active material, and may include a conductive agent such as a carbonaceous material and a binder such as polyvinylidene fluoride as necessary. .
As the positive electrode active material, for example, a lithium-containing metal composite oxide containing a sufficient amount of lithium (Li), for example, lithium represented by the general formula LixMO ₂ and a transition metal is preferable. This is because the lithium-containing metal composite oxide can generate a high voltage and has a high density, so that it is possible to further increase the capacity of the secondary battery. M is one or more transition metals, and for example, at least one of the group consisting of cobalt, nickel and manganese is preferable. x varies depending on the charge / discharge state of the battery and is usually a value in the range of 0.05 ≦ x ≦ 1.10.
Specific examples of such a lithium-containing metal composite oxide include LiCoO _{2 and} LiNiO ₂ . In addition, any 1 type may be used for a positive electrode active material, and 2 or more types may be mixed and used for it.

Further, the inner surface positive electrode active material layer 12 and the outer surface positive electrode active material layer 13 of the positive electrode 9 have a charge / discharge capacity equivalent to 250 mAh or more per 1 g of the negative electrode carbonaceous material in a steady state (for example, after repeating charge / discharge about 5 times). It is necessary to contain Li, it is desirable to include Li corresponding to a charge / discharge capacity of 300 mAh or more, and it is more preferable to include Li corresponding to a charge / discharge capacity of 330 mAh or more.
Note that it is not always necessary to supply Li from the inner surface positive electrode active material layer 12 and the outer surface positive electrode active material layer 13. For example, in a solvent to be described later, the charge / discharge capacity is equivalent to 250 mAh or more per gram of carbonaceous material in the battery system. It is sufficient that a minute amount of Li exists. The amount of Li is appropriately selected according to the measurement of the discharge capacity of the battery.

  On the other hand, as the material constituting the inner-surface negative electrode active material layer 15 and the outer-surface negative electrode active material layer 16 constituting the negative electrode 10, a carbonaceous material capable of doping / dedoping (desorption / desorption) lithium, or an alloy with lithium is formed. Possible metals or alloy compounds containing the metals are mentioned.

  Examples of carbonaceous materials include non-graphitizable carbon, graphites such as artificial graphite and natural graphite, pyrolytic carbons, cokes (pitch coke, needle coke, petroleum coke, etc.), glassy carbons, organic high carbon At least one kind of carbonaceous material such as molecular compound fired body (phenol resin, furan resin, etc., fired at an appropriate temperature and carbonized), activated carbon, fibrous carbon, or the like can be used. Moreover, you may include the material which does not contribute to charging / discharging.

Examples of the alloy compound include those containing at least one metal that can be alloyed with lithium. Specifically, when the metal element capable of forming an alloy with lithium is M, the chemical formula MxM′yLiz (M ′ is one or more metal elements other than Li element and M element, x> 0, y ≧ 0, z It can be mentioned as a compound having a composition of ≧ 0). Note that in this specification, elements such as B, Si, and As, which are semiconductor elements, are also included in the metal elements.
Examples of such metals and metal compounds include Mg, B, Al, Ga, In, Si, Ge, Sn, Pb, Sb, Bi, Cd, Ag, Zn, Hf, Zr, and Y, and those. Alloy compounds of Li, Al-Li, Li-Al-M (M: 2A, 3B, 4B, composed of one or more of transition metal elements), AlSb, CuMgSb, and the like.

In particular, it is preferable to use a group 4B typical element as an element capable of forming an alloy with lithium, and more preferably Si or Sn. For example, MxSi, MxSn (M is one or more metal elements each excluding Si or Sn). The compound represented by these can be mentioned. _{Specifically, SiB 4, SiB 6, Mg} 2 Si, Mg 2 Sn, Ni 2 Si, TiSi 2, MoSi 2, CoSi 2, NiSi 2, CaSi 2, CrSi 2, Cu 5 Si, FeSi 2, MnSi 2 NbSi ₂ , TaSi ₂ , VSi ₂ , WSi ₂ , ZnSi _2, etc.
Moreover, in the battery of this embodiment, the inner surface negative electrode active material layer 15 and the outer surface negative electrode active material layer 16 can also be comprised by 4B group compounds other than carbon containing one or more nonmetallic elements. Specifically, for example, SiC, Si ₃ N ₄ , Si ₂ N ₂ O, Ge ₂ N ₂ O, SiOx (0 <x ≦ 2), SnOx (0 <x ≦ 2), LiSiO, LiSnO, etc. Can do.

Examples of the method for producing the negative electrode active material layer using these materials include a mechanical alloying method, a method in which raw material compounds are mixed and heat-treated in an inert atmosphere, a melt spinning method, a gas atomizing method, a water atomizing method, and the like. Although it is mentioned, it is not limited to this. In addition, each material may or may not be pulverized, or two or more materials may be mixed.
Further, the doping of lithium into the negative electrode active material layer may be performed electrochemically in the battery after the battery is manufactured, or supplied from a positive electrode or a lithium source other than the positive electrode after the battery is manufactured or before the battery is manufactured. It may be electrochemically doped, synthesized as a lithium-containing material during material synthesis, and contained in the negative electrode during battery fabrication.

  In addition, as the negative electrode current collector 14, the negative electrode current collector of the present invention described above is used, and the first main surface 14a and the second main surface 14b have the predetermined rust preventive layer (not shown). Yes.

The separators 7 and 8 are for preventing a short circuit due to physical contact between the positive electrode 9 and the negative electrode 10 while allowing lithium ions to pass. For example, the separators 7 and 8 are made of a microporous polyolefin film such as a polyethylene film or a polypropylene film. It is configured.
In order to ensure safety, the separators 7 and 8 preferably have a function of blocking the current by closing the holes by heat melting at a predetermined temperature (for example, 120 ° C.) or higher to cut off the current.

  The separators 7 and 8 are impregnated with an electrolytic solution (not shown) which is an example of a nonaqueous electrolyte composition. The electrolytic solution in the present embodiment includes, for example, a nonaqueous solvent and a lithium salt that is an electrolyte salt dissolved in the solvent, and may include various additives as necessary.

  Examples of the non-aqueous solvent include propylene carbonate, ethylene carbonate, diethyl carbonate, methyl ethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3. -Dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methyl sulfolane, acetonitrile, propylnitrile, anisole, acetate or propionate.

In addition, as a solvent, any 1 type of these may be used, but 2 or more types may be mixed and used.
When mixing and using, the structure which added asymmetrical chain carbonates, such as methyl ethyl carbonate and methyl propyl carbonate, as a 2nd component especially using ethylene carbonate as a main solvent is suitable. Further, a mixed solvent of methyl ethyl carbonate and dimethyl carbonate can be used. In this case, the volume ratio to be mixed is preferably in the range of ethylene carbonate: second component solvent = 7: 3 to 3: 7. Moreover, when using the above-mentioned mixed solvent as a 2nd component solvent, it is preferable to make a volume ratio into the range of methyl ethyl carbonate: dimethyl carbonate = 2: 8-9: 1.
Addition of the second component suppresses decomposition of the main solvent, improves conductivity and improves current characteristics, reduces freezing point of electrolyte and improves low temperature characteristics, reaction with lithium metal The effect that safety | security falls and safety is improved is acquired.

As the electrolyte, LiPF ₆ is suitable, but any of those used in this type of battery can be used. For example, as a lithium salt, LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiCH ₃ SO ₃ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (C ₄ F ₉ SO ₂ ) (CF ₃ SO ₂ ), LiCl or LiBr. Among these, LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiCH ₃ SO ₃ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ or LiN (C ₄ F ₉ SO ₂ ) (CF ₃ SO ₂ ) is preferred, with LiPF ₆ or LiBF ₄ being particularly preferred. Any one of the lithium salts may be used, or a mixture of two or more may be used.

Next, a method for manufacturing such a battery will be described.
In this embodiment, the negative electrode is manufactured using graphite as the main component of the active material layer.
First, natural graphite is pulverized using a pulverizer such as a hammer mill, a pin mill, a ball mill, a jet mill, etc., and finally, graphite particles that are the main component of the active material layer of the battery are obtained. Specifically, for example, when a hammer mill is used, it is preferable to perform pulverization for 20 minutes or more at a rotation speed of 4000 to 5000 min ⁻¹ . The supply of natural graphite and the discharge of graphite particles are desirably performed by a method involving the graphite particles in an air stream.

  Styrene butadiene rubber (SBR) is added to the resulting graphite particles as a binder, and carboxymethyl cellulose (CMC) is mixed as a thickener to prepare a negative electrode mixture, and N-methyl-2-pyrrolidone ( NMP) to obtain a paste-like kneaded body (slurry). In this way, the kneaded body preparation step is performed.

Thereafter, the obtained kneaded body is a thin plate-like (band-like) copper foil current collector having the predetermined antirust layer, that is, the antirust layer contains at least one of Ni, Cr, Zn and In, and is It is applied onto a copper foil current collector that has been subjected to electrodeposition adjustment or oxidation treatment so that the main form of the rust layer is hydroxide or oxide, and then, for example, at a temperature of 80 ° C. to 110 ° C. with a spray dryer, nitrogen or A calcination treatment that dries under an active gas is performed, the kneaded body is dried and the binder is burned off to obtain a negative electrode in which an active material layer is formed on the current collector. If necessary, you may press-mold according to the target volume density.
In this way, the coating and drying process is performed.

In the present embodiment, the negative electrode is manufactured by the above procedure.
Subsequently, a mixture of lithium carbonate 0.5 molar and cobalt 1 mole carbonate, after obtaining the LiCoO ₂ was fired for 5 hours in a 900 ° C. in air, grinding the LiCoO _2, obtained by a laser diffraction method 50 A LiCoO ₂ powder having a% cumulative particle size of 15 μm was prepared. Thereafter, 91 parts by weight of a mixture comprising 95 parts by weight of LiCoO ₂ powder and 5 parts by weight of lithium carbonate powder, 6 parts by weight of graphite as a conductive agent, and 3 parts by weight of polyvinylidene fluoride as a binder were prepared to prepare a positive electrode mixture. And dispersed in a solvent (N-methylpyrrolidone) to form a slurry (paste). The positive electrode mixture slurry was uniformly applied to both surfaces of a 20 μm-thick strip-shaped aluminum foil that finally became the positive electrode current collector, and dried and compression molded to produce a thin plate-shaped positive electrode.
In addition, the process with an alkali metal is performed with respect to a solvent similarly to a negative electrode as needed.

Thereafter, the prepared negative electrode and positive electrode and a separator made of a microporous polypropylene film having a thickness of 25 μm were laminated in the order of the negative electrode, the separator, the positive electrode, and the separator and then wound many times, and the spiral winding with an outer diameter of 18 mm The body was made.
This spiral wound body is housed in a nickel-plated iron battery can, insulating plates are provided on both the upper and lower surfaces of the spiral electrode, and the aluminum positive electrode lead is led out from the positive electrode current collector to the battery lid. The nickel negative electrode lead was led out from the negative electrode current collector and welded to the bottom of the battery can.

Thereafter, an electrolytic solution composition in which LiPF ₆ is dissolved in a nonaqueous solvent (for example, an equal volume mixed solvent of ethylene carbonate and diethyl carbonate) at a rate of 1 mol / dm ³ in a battery can in which the wound body is housed. The positive electrode, the negative electrode, and the separator were impregnated with the electrolytic solution composition.
Subsequently, the battery lid was caulked through an insulating sealing gasket whose surface was coated with asphalt to fix the safety valve mechanism having a current interruption function, the PTC element, and the battery lid, and the inside was hermetically sealed. Get a battery.

  Next, FIG. 9 is an exploded perspective view showing an embodiment of the second nonaqueous electrolyte secondary battery of the present invention, and shows a so-called laminate type secondary battery.

  In this figure, the secondary battery is configured by enclosing a battery element 60 to which a positive electrode lead 51 and a negative electrode lead 52 are attached in a film-like exterior member 70. The positive electrode lead 51 and the negative electrode lead 52 are led out, for example, in the same direction from the inside of the exterior member 70 to the outside. The positive electrode lead 51 and the negative electrode lead 52 are each composed of a metal material such as aluminum (Al), copper (Cu), nickel (Ni), or stainless steel.

Here, the negative electrode lead 52 is obtained by rolling wire drawing, and either or both of chamfering and R processing are applied to the edge.
By using such a lead, it is possible to prevent the metallic foreign matter from being mixed into the battery due to the drop of the slit burr at the time of battery assembly. In addition, when a nickel lead is used for the negative electrode, if a similar burr drop occurs, there is a high possibility of causing a large current short-circuit, but this can be effectively prevented, thus improving the reliability of the battery. Furthermore, the sealing performance of the negative electrode lead disposed in the battery element is improved.

The exterior member 70 is configured by a rectangular laminate film in which, for example, a nylon film, an aluminum foil, and a polyethylene film are bonded together in this order. The exterior member 70 is disposed, for example, so that the polyethylene film side and the battery element 60 face each other, and the outer edge portions are joined to each other by fusion or adhesive.
An adhesion film (not shown) is inserted between the exterior member 70 and the positive electrode lead 51 and the negative electrode lead 52 to prevent the outside air from entering. The adhesion film is made of a material having adhesion to the positive electrode lead 51 and the negative electrode lead 52. For example, when the positive electrode lead 51 and the negative electrode lead 52 are made of the metal materials described above, polyethylene, polypropylene, and modified polyethylene are used. Or it is preferable to comprise by polyolefin resin, such as a modified polypropylene.

In addition, the exterior member 70 may be configured by another structure, for example, a laminate film having no metal material, a polymer film such as polypropylene, or a metal film, instead of the above-described laminate film.
Here, the general structure of an exterior member can be represented by the laminated structure of an exterior layer / metal foil / sealant layer (however, the exterior layer and the sealant layer may be composed of a plurality of layers), and the above. In this example, the nylon film corresponds to the exterior layer, the aluminum foil corresponds to the metal foil, and the polyethylene film corresponds to the sealant layer.
In addition, as metal foil, it is sufficient if it functions as a moisture-permeable barrier film, and not only aluminum foil but also stainless steel foil, nickel foil and plated iron foil can be used, but it is thin and lightweight. Thus, an aluminum foil excellent in workability can be suitably used.

  As the exterior member 70, usable configurations are listed in the form of (exterior layer / metal foil / sealant layer): Ny (nylon) / Al (aluminum) / CPP (unstretched polypropylene), PET (polyethylene terephthalate) / Al / CPP, PET / Al / PET / CPP, PET / Ny / Al / CPP, PET / Ny / Al / Ny / CPP, PET / Ny / Al / Ny / PE (polyethylene), Ny / PE / Al / LLDPE ( Linear low density polyethylene), PET / PE / Al / PET / LDPE (low density polyethylene), and PET / Ny / Al / LDPE / CPP.

It is a schematic perspective view which shows an example of the slit system which manufactures a conventional product. It is sectional drawing which shows an example of the electrode lead of a conventional product and this invention product. It is a partial notch perspective view which shows one Embodiment of the nonaqueous electrolyte secondary battery of this invention. It is sectional drawing which shows typically the cross-section of the wound body in FIG. It is sectional drawing which shows typically the cross-section of the nonaqueous electrolyte secondary battery using the conventional product and this invention product. It is a graph which shows cycling characteristics. It is sectional drawing which shows typically the cross-section of the outer edge of the nonaqueous electrolyte secondary battery of this invention. It is sectional drawing which shows typically the cross-sectional structure of the outer edge of the nonaqueous electrolyte secondary battery of a conventional product. It is a disassembled perspective view which shows other embodiment of the nonaqueous electrolyte secondary battery of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Battery, 2 ... Battery can, 3 ... Rolled body, 4 ... Center pin, 5 ... Battery cover, 6 ... Gasket, 7, 8, 64 ... Separator, 9, 61 ... Positive electrode, 10, 62 ... Negative electrode, 11 , 61A ... Positive electrode current collector, 12, 13, 61B ... Positive electrode active material layer, 14, 62A ... Negative electrode current collector, 15, 16, 62B ... Negative electrode active material layer, 17, 51 ... Positive electrode lead, 18 ... Safety valve mechanism , 19 ... heat-sensitive resistance element, 20 ... insulating plate, 30, 52 ... negative electrode lead, 60 ... battery element, 63 ... nonaqueous electrolyte composition layer, 65 ... protective tape, 70 ... exterior member

Claims (7)

An electrode lead used in a nonaqueous electrolyte secondary battery having an electrode laminate structure,
An electrode lead, wherein the edge is chamfered and / or rounded.   2. The electrode lead according to claim 1, wherein the electrode lead is a nickel-based lead. In producing an electrode lead used for a nonaqueous electrolyte secondary battery having an electrode laminated structure,
A method for producing an electrode lead, comprising: rolling a drawn wire and subjecting the edge portion to chamfering and / or R processing. A positive electrode having a positive electrode active material capable of occluding and releasing lithium and a positive electrode current collector, a negative electrode having a negative electrode active material capable of occluding and releasing lithium and a negative electrode current collector, and disposed between the positive electrode and the negative electrode In a non-aqueous electrolyte secondary battery comprising a separator, a non-aqueous electrolyte composition, and a battery can containing these,
A non-aqueous electrolyte secondary battery, wherein an edge portion of an electrode lead connecting the electrode and the battery can is chamfered and / or rounded. A positive electrode having a positive electrode active material capable of occluding and releasing lithium and a positive electrode current collector, a negative electrode having a negative electrode active material capable of occluding and releasing lithium and a negative electrode current collector, and disposed between the positive electrode and the negative electrode In a non-aqueous electrolyte secondary battery comprising a separator, a non-aqueous electrolyte composition, and a negative electrode can containing these,
The nonaqueous electrolyte secondary battery according to claim 4, wherein the edge portion of the electrode lead connecting the negative electrode and the negative electrode can is chamfered and / or R processed. A positive electrode having a positive electrode active material capable of occluding and releasing lithium and a positive electrode current collector, a negative electrode having a negative electrode active material capable of occluding and releasing lithium and a negative electrode current collector, and disposed between the positive electrode and the negative electrode In a non-aqueous electrolyte secondary battery comprising a separator, a non-aqueous electrolyte composition, and a laminate exterior housing these,
A nonaqueous electrolyte secondary battery, wherein an edge portion of an electrode lead connected to a negative electrode is chamfered and / or rounded.   The non-aqueous electrolyte secondary battery according to any one of claims 4 to 6, wherein the electrode lead is a nickel-based lead.

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