JP6241529B2 - Method for producing non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte secondary battery having a configuration in which a non-aqueous electrolyte easily penetrates into a flat wound electrode body even when the viscosity of the non-aqueous electrolyte is high.

  Non-aqueous electrolytes typified by alkaline secondary batteries typified by nickel-hydrogen batteries and lithium-ion batteries as drive power sources for portable electronic devices such as mobile phones including smartphones, portable computers, PDAs, and portable music players Secondary batteries are often used. In addition, the power supply for driving electric vehicles (EV) and hybrid electric vehicles (HEV, PHEV), solar power generation, wind power generation, and other applications for suppressing output fluctuations, and for use in the daytime to save power at night Alkaline secondary batteries and non-aqueous electrolyte secondary batteries are also frequently used in stationary storage battery systems such as system power peak shift applications.

  Especially for EV, HEV, PHEV use or stationary storage battery systems, high capacity and high output characteristics are required. Therefore, each battery is enlarged, and many batteries are connected in series or in parallel. Is done. Therefore, in these applications, non-aqueous electrolyte secondary batteries are generally used from the viewpoint of space efficiency. Furthermore, when physical strength is required, as a battery exterior body, generally, a metal square exterior body having an opening on one side and a metal sealing body for sealing the opening are employed. Yes.

In non-aqueous electrolyte secondary batteries for use in applications such as those mentioned above, it is essential to extend the life, so various additives are added to the non-aqueous electrolyte to prevent deterioration. ing. For example, Patent Document 1 below shows that a salt having a cyclic phosphazene compound and various oxalato complexes as anions is added to a non-aqueous electrolyte of a non-aqueous electrolyte secondary battery. Patent Documents 2 and 3 below describe lithium bis (oxalato) borate (Li [B (C ₂ O ₄ ) represented by the following structural formula (I), which is one type of lithium salt having an oxalato complex as an anion. ₂ ), hereinafter referred to as “LiBOB”).

Furthermore, in Patent Document 4 below, for the purpose of suppressing self-discharge during charge storage and improving the storage characteristics after charge, non-aqueous electrolyte is added with lithium difluorophosphate (LiPF ₂ O ₂ ). An invention of a water electrolyte secondary battery is disclosed.

JP 2009-129541 A Special table 2010-53856 gazette JP 2010-108624 A Japanese Patent No. 3439085

  When the cyclic phosphazene compound disclosed in Patent Document 1 and a salt having various oxalato complexes as anions are added to the non-aqueous electrolyte, flame retardancy of the non-aqueous electrolyte is improved, and excellent battery characteristics are obtained. A non-aqueous electrolyte secondary battery having high safety can be obtained. Further, when LiBOB disclosed in Patent Documents 2 and 3 is added to the non-aqueous electrolyte, a thin and extremely stable lithium ion conductive layer is formed on the surface of the carbon negative electrode active material of the non-aqueous electrolyte secondary battery. Since a protective layer is formed and this protective layer is stable even at high temperatures, the decomposition reaction of the non-aqueous electrolyte by the carbon negative electrode active material is suppressed, and good cycle characteristics can be obtained and the safety of the battery is improved. There is an excellent effect.

Furthermore, according to the nonaqueous electrolyte secondary battery disclosed in Patent Document 4, LiPF ₂ O ₂ and lithium react to form a high-quality protective film at the interface between the positive electrode active material and the negative electrode active material, Since this protective coating suppresses direct contact between the charged active material and the organic solvent, the decomposition of the non-aqueous electrolyte caused by the contact between the active material and the non-aqueous electrolyte is suppressed, and the charge storage characteristics are improved. To do.

On the other hand, in a non-aqueous electrolyte secondary battery having high capacity and high output characteristics, a flat wound electrode body produced by winding a positive electrode plate, a negative electrode plate, and a separator with a wide electrode plate width is used. ing. In a non-aqueous electrolyte secondary battery using a flat wound electrode having such a wide electrode plate width, it is difficult to penetrate the non-aqueous electrolyte in the electrode plate width direction, and the inner peripheral side is the outer periphery. It becomes more difficult to penetrate than the side. In particular, a non-aqueous electrolyte using a non-aqueous electrolyte having a high cyclic carbonate content ratio or a non-aqueous electrolyte in which a lithium salt or LiPF ₂ O ₂ having an oxalato complex as an anion is added to the non-aqueous solvent In the secondary battery, since the viscosity of the nonaqueous electrolytic solution is increased, the electrolytic solution is less likely to penetrate into the flat wound electrode body. Further, when producing a flat wound electrode body, after winding the positive electrode plate, the negative electrode plate and the separator, and then forming a flat wound electrode body by pressure molding, Since the negative electrode plate and the separator are in close contact with each other, the influence of the viscosity of the non-aqueous electrolyte is significant.

Even if a non-aqueous electrolyte in which a lithium salt or LiPF ₂ O ₂ having an oxalato complex as an anion is added to a non-aqueous solvent as a non-aqueous electrolyte of a non-aqueous electrolyte secondary battery is used, It is an object of the present invention to provide a non-aqueous electrolyte secondary battery in which the non-aqueous electrolyte easily penetrates into the center of a wound electrode body so that the time required for injecting the non-aqueous electrolyte does not become long.

In order to achieve the above object, the nonaqueous electrolyte secondary battery of the present invention comprises:
A flat wound electrode body obtained by winding a long positive electrode plate and a long negative electrode plate through a long separator;
The flat wound electrode body and an exterior body that houses the non-aqueous electrolyte,
A non-aqueous electrolyte secondary battery produced by using a non-aqueous electrolyte containing at least one of a lithium salt having an oxalato complex as an anion and lithium difluorophosphate,
Eight or more layers of winding portions of only the separator exist in the central portion of the flat winding electrode body.

In the flat wound electrode body, it is difficult for the nonaqueous electrolyte to penetrate in the width direction of the electrode plate, and the nonaqueous electrolyte does not easily enter the center of the flat wound electrode body. Further, when the non-aqueous electrolyte contains at least one of a lithium salt having an oxalato complex as an anion and LiPF ₂ O ₂ , the viscosity of the non-aqueous electrolyte is increased, and thus a flatter wound electrode body It becomes difficult for the non-aqueous electrolyte to enter up to the central part. In the non-aqueous electrolyte secondary battery of the present invention, since the winding portion of only the separator is provided in the central portion of the flat wound electrode body in 8 layers or more, even in the case of a non-aqueous electrolyte with high viscosity, the flat shape The non-aqueous electrolyte easily penetrates to the center of the spirally wound electrode body, and when the non-aqueous electrolyte is insufficient at the time of charge / discharge, excess non-aqueous electrolysis is present outside the flat wound electrode body. The liquid is easily introduced into the flat wound electrode body. Therefore, according to the non-aqueous electrolyte secondary battery of the present invention, the effect of adding a lithium salt or LiPF ₂ O ₂ having an oxalato complex as an anion to the non-aqueous electrolyte is favorably exhibited. .

  In the case where a flat wound electrode body is formed with the positive electrode plate and the negative electrode plate insulated from each other via a separator, two separators are usually used. Therefore, when two separators are wound two or more times, eight or more layers of only the separator are formed at the center of the flat wound electrode body. Further, when the winding start positions of the two separators are different and the number of stacked layers of each separator is different, the total number of stacked layers of each separator may be 8 layers or more. When the number of winding portions of the separator is less than 8 layers, the non-aqueous electrolyte solution is less likely to enter the central portion of the flat wound electrode body as the number decreases. Moreover, although the upper limit of the winding part of only a separator is arbitrary, it is preferable to stop at about 12 layers.

In addition, as a positive electrode active material which can be used with the nonaqueous electrolyte secondary electricity of this invention, if it is a compound which can occlude / release lithium ion reversibly, it can select suitably and can be used. As these positive electrode active materials, lithium transition metal composite oxidation represented by LiMO ₂ (wherein M is at least one of Co, Ni, and Mn) capable of reversibly occluding and releasing lithium ions. things, _{namely, LiCoO 2, LiNiO 2, LiNi} y Co 1-y O 2 (y = 0.01~0.99), LiMnO 2, LiCo x Mn y Ni z O 2 (x + y + z = 1) and, LiMn ₂ O ₄ or LiFePO ₄ can be used singly or in combination. Furthermore, what added different metal elements, such as zirconium, magnesium, and aluminum, to lithium cobalt complex oxide can also be used.

Non-aqueous solvents that can be used in the non-aqueous electrolyte of the non-aqueous electrolyte secondary battery of the present invention include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), fluorine Cyclic carbonates, cyclic carboxylic acid esters such as γ-butyrolactone (γ-BL), γ-valerolactone (γ-VL), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC) Chain carbonates such as methylpropyl carbonate (MPC) and dibutyl carbonate (DBC), fluorinated chain carbonates, methyl pivalate, ethyl pivalate, methyl isobutyrate, methyl propionate, etc. Carboxylic acid ester, N, N'-dimethylforma De, amide compounds such as N- methyl oxazolidinone, etc. sulfur compounds such as sulfolane may be exemplified. It is desirable to use a mixture of two or more of these.

In the present invention, a lithium salt generally used as an electrolyte salt in a nonaqueous electrolyte secondary battery can be used as an electrolyte salt dissolved in a nonaqueous solvent. Such lithium salts include LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , LiAsF ₆ , LiClO ₄ , Li ₂ B ₁₀ Cl ₁₀ , Li ₂ B ₁₂ Cl ₁₂ , and mixtures thereof Illustrated. Among these, LiPF ₆ (lithium hexafluorophosphate) is particularly preferable. The amount of electrolyte salt dissolved in the non-aqueous solvent is preferably 0.8 to 1.5 mol / L.

In the nonaqueous electrolyte secondary battery of the present invention, the content of the lithium salt having the oxalato complex in the nonaqueous electrolyte as an anion is 0.01 to 2.0 mol /% at the time of preparing the nonaqueous electrolyte secondary battery.
L is preferable, and 0.05 to 0.2 mol / L is more preferable. In addition, the content of LiPF ₂ O ₂ in the non-aqueous electrolyte in the non-aqueous electrolyte secondary battery of the present invention may be 0.01 to 2.0 mol / L at the time of manufacturing the non-aqueous electrolyte secondary battery. Preferably 0
. It is more preferable to set it as 01-0.1 mol / L. In the non-aqueous electrolyte secondary battery of the present invention, the amount of lithium salt or LiPF ₂ O ₂ having an oxalato complex as an anion in the non-aqueous electrolyte is mainly a lithium salt or LiPF ₂ O ₂ itself having an oxalato complex as an anion. It can also be added as an electrolyte salt of the component. However, when the amount of lithium salt or LiPF ₂ O ₂ having an oxalato complex as an anion in the non-aqueous electrolyte increases, the viscosity of the non-aqueous electrolyte increases. Further, a lithium salt or LiPF ₂ O ₂ having an oxalato complex as an anion may be added as a small amount, for example, about 0.1 mol / L. In the case to no lithium salt as an anion the oxalate complex of adding LiPF ₂ O ₂ as an additive, to no lithium salt as an anion every oxalate complex during the initial charging by the amount of addition is LiPF ₂ O _2, a positive electrode It is consumed for forming a protective film on the plate or on the negative electrode plate, and there may be a case where lithium salt or LiPF ₂ O ₂ having an oxalato complex as an anion is not substantially present in the non-aqueous electrolyte. Cases are also included in the present invention. Therefore, it is included in the present invention if a lithium salt or LiPF ₂ O ₂ having an oxalato complex as an anion is contained in the non-aqueous electrolyte in a state before the first charge to the non-aqueous electrolyte secondary battery. It is.

In the nonaqueous electrolyte secondary battery of the present invention,
The positive electrode plate is formed with a positive electrode core exposed portion along the longitudinal direction,
The negative electrode plate is formed with a negative electrode core exposed portion along the longitudinal direction,
The flat wound electrode body has a positive electrode core exposed portion wound around one end, and a negative electrode core exposed portion wound around the other end.
A current collector is welded to at least one of the positive electrode core exposed portion and the negative electrode core exposed portion,
It is preferable that a welded portion between at least one of the positive electrode core exposed portion and the negative electrode core exposed portion and the current collector is deviated from a winding center axis of the wound electrode body.

  With such a configuration, the non-aqueous electrolyte can easily enter the central portion of the wound electrode body from the region corresponding to the winding center axis.

Moreover, in the nonaqueous electrolyte secondary battery of the present invention, the exterior body includes a bottomed cylindrical rectangular exterior body having an opening and a sealing body that seals the opening,
It is preferable that the number of the welded portions is one and is shifted from the winding center axis of the wound electrode body toward the sealing body.

  With such a configuration, the non-aqueous electrolyte can easily enter the central portion of the wound electrode body from the region corresponding to the winding center axis and the region on the bottom side of the exterior body.

  Further, in the nonaqueous electrolyte secondary battery of the present invention, the exterior body includes a bottomed cylindrical rectangular exterior body having an opening and a sealing body that seals the opening, It is preferable that there are two locations, which are shifted from the winding center axis of the flat wound electrode body toward the sealing body side and the bottom side of the rectangular exterior body, respectively.

  With such a configuration, the non-aqueous electrolyte can easily penetrate into the central portion of the wound electrode body from the region corresponding to the winding center axis.

  In the nonaqueous electrolyte secondary battery of the present invention, it is preferable that the number of windings of the positive electrode plate and the negative electrode plate is 30 or more, respectively. The battery capacity is preferably 20 Ah or more.

When the number of turns of the positive electrode plate and the negative electrode plate is large, it is difficult for the non-aqueous electrolyte to enter the center portion of the flat wound electrode body, and when the battery capacity is large, the number of turns of the positive electrode plate and the negative electrode plate is Even if the amount is small, it is difficult for the non-aqueous electrolyte to penetrate into the central portion of the flat wound electrode body in the electrode plate width direction. Therefore, when the number of windings of the positive electrode plate and the negative electrode plate is large or when the battery capacity is large, the above-described effect of the present invention appears well.

In the nonaqueous electrolyte secondary battery of the present invention, the lithium salt having the oxalato complex as an anion is lithium bis (oxalato) borate ((Li [B (C ₂ O ₄ ) ₂ ], hereinafter referred to as “LiBOB”). It may be expressed as

  When LiBOB is used as a lithium salt having an oxalato complex as an anion, a nonaqueous electrolyte secondary battery capable of achieving better cycle characteristics can be obtained. In addition, preferable content of LiBOB is 0.01-2.0 mol / L, More preferably, it is 0.05-0.2 mol / L.

  Moreover, in this invention, it is preferable that the said negative electrode core exposure part is formed along the longitudinal direction at the both ends of the width direction of the said negative electrode plate. In such a case, it is preferable that one side of the negative electrode core exposed portion is formed wider than the other side, and the wide side core exposed portion is connected to the negative electrode current collector.

  With such a configuration, the heat generated inside the electrode body is easily radiated from both ends in the width direction of the negative electrode core exposed portion, and the temperature rise inside the electrode body is suppressed.

  Moreover, it is preferable that a protective layer made of metal oxide particles and a binder is formed on at least one surface of the positive electrode plate and the negative electrode plate. Here, it is preferable to use alumina, titania, zirconia, or the like as the metal oxide. As the binder, an acrylate resin is preferably used.

  Further, in the present invention, the negative electrode core exposed portion is formed along the longitudinal direction at both ends in the width direction of the negative electrode plate, and a protective layer made of metal oxide particles and a binder is formed on the negative electrode plate surface. Preferably, the protective layer is formed on both ends of the negative electrode plate in the width direction along the longitudinal direction, and is also formed on both surfaces of the negative electrode core exposed portion.

  With such a configuration, the protective layer is porous and insulative due to the presence of metal oxide particles, so that a fine gap is formed between the negative electrode plate and the separator. Thus, the non-aqueous electrolyte can easily penetrate into the central portion of the wound electrode body. In addition, since the insulation between the negative electrode core exposed portion and the positive electrode core exposed portion facing the positive electrode core exposed portion through the separator is improved, the non-aqueous electrolyte secondary having excellent reliability A battery is obtained.

FIG. 1A is a plan view of a rectangular nonaqueous electrolyte secondary battery according to Embodiment 1, and FIG. 1B is a front view of the same. 2A is a partial cross-sectional view taken along line IIA-IIA in FIG. 1A, FIG. 2B is a partial cross-sectional view taken along line IIB-IIB in FIG. 2A, and FIG. 2C is taken along line IIC-IIC in FIG. FIG. 3A is an enlarged cross-sectional view of a winding center portion of a flat wound electrode body used in the rectangular nonaqueous electrolyte secondary battery of Embodiment 1. FIG. 4A is a view corresponding to FIG. 2A of the rectangular nonaqueous electrolyte secondary battery of Embodiment 2, and FIG. 4B is a cross-sectional view taken along the line IVB-IVB of FIG. 4A. 5A is a view corresponding to FIG. 2A of the rectangular nonaqueous electrolyte secondary battery of Embodiment 3, and FIG. 5B is a cross-sectional view taken along the line VB-VB of FIG. 5A. It is a top view of the negative electrode plate obtained by using with the square nonaqueous electrolyte secondary battery of a modification.

  Hereinafter, various embodiments of the present invention will be described in detail with reference to the drawings. However, each embodiment shown below is illustrated for understanding the technical idea of the present invention, and is not intended to specify the present invention to this embodiment. The present invention can be equally applied to various modifications without departing from the technical idea shown in the scope.

[Embodiment 1]
First, the prismatic nonaqueous electrolyte secondary battery of Embodiment 1 will be described with reference to FIGS. As shown in FIG. 3, the rectangular nonaqueous electrolyte secondary battery 10 includes a flat wound electrode in which a positive electrode plate 11 and a negative electrode plate 12 are wound in a state of being insulated from each other via a separator 13. It has a body 14. The outermost surface side of the flat wound electrode body 14 is covered with the separator 13, but the negative electrode plate 12 is arranged on the outer peripheral side of the positive electrode plate 11. When the flat wound electrode body 14 is formed in a state where the positive electrode plate 11 and the negative electrode plate 12 are insulated from each other through the separator 13, two separators are usually used. In this case, the central portion of the flat wound electrode body 14 is in a state where only the two separators 13 are wound twice so that the nonaqueous electrolytic solution can easily enter the inside, that is, individual A total of eight layers of separators 13 are stacked. Note that “CP” in FIG. 3 indicates the winding center position of the flat wound electrode body 14.

  The positive electrode plate 11 is coated with a positive electrode active material mixture on both surfaces of a positive electrode core body 11b made of aluminum foil, dried and rolled, and then the aluminum foil is exposed in a strip shape along one end in the width direction. It is produced by slitting the positive electrode plate 11. The aluminum foil portion exposed in the band shape becomes the positive electrode core exposed portion 15. The negative electrode plate 12 is formed by applying a negative electrode active material mixture on both surfaces of a negative electrode core 12b made of copper foil, drying and rolling, and then exposing the copper foil in a strip shape along one end in the width direction. Thus, the negative electrode plate 12 is produced by slitting. The copper foil portion exposed in the band shape becomes the negative electrode core exposed portion 16.

  In addition, the width | variety and length of the negative electrode active material mixture layer 12a of the negative electrode plate 12 are larger than the width | variety and length of the positive electrode active material mixture layer 11a. Here, a positive electrode core having a thickness of about 10 to 20 μm made of aluminum or an aluminum alloy is used, and a negative electrode core having a thickness of about 5 to 15 μm made of copper or a copper alloy is used. preferable. Moreover, the specific composition of the positive electrode active material mixture layer 11a and the negative electrode active material mixture layer 12a will be described later.

  Then, the positive electrode plate 11 and the negative electrode plate 12 obtained as described above are overlapped with the active material mixture layer of the electrode in which the aluminum foil exposed portion of the positive electrode plate 11 and the copper foil exposed portion of the negative electrode plate 12 face each other. 2A and 2B, by providing a plurality of stacked positive electrode core exposed portions 15 at one end as shown in FIGS. 2A and 2B. At the other end, a flat wound electrode body 14 having a plurality of overlapping negative electrode core exposed portions 16 is produced. The separator 13 is preferably a microporous membrane made of polyolefin.

  A plurality of laminated positive electrode core exposed portions 15 are electrically connected to a positive electrode terminal 18 made of the same aluminum material via a positive electrode current collector 17 made of an aluminum material, and a plurality of laminated negative electrode core bodies are exposed. The part 16 is electrically connected to a negative electrode terminal 20 also made of a copper material via a negative electrode current collector 19 made of a copper material. As shown in FIGS. 1A, 1B, and 2A, the positive electrode terminal 18 and the negative electrode terminal 20 are fixed to a sealing body 23 made of, for example, an aluminum material via insulating members 21 and 22, respectively. Further, the positive terminal 18 and the negative terminal 20 are connected to a positive external terminal and a negative external terminal (both not shown) as necessary.

The flat wound electrode body 14 produced as described above has a rectangular exterior body 25 made of, for example, an aluminum material in which an insulating resin sheet 24 is interposed in the periphery except the sealing body 23 side, and one surface is opened. Inserted inside. Thereafter, the sealing body 23 is fitted into the opening of the rectangular exterior body 25, the fitting portion between the sealing body 23 and the rectangular exterior body 25 is laser-welded, and a non-aqueous electrolyte is supplied from the electrolyte injection hole 26. The nonaqueous electrolyte secondary battery 10 according to the first embodiment is manufactured by pouring and sealing the electrolyte solution injection port 26.

  A current interruption mechanism 27 that is operated by gas pressure generated inside the battery is provided between the positive electrode current collector 17 and the positive electrode terminal 18. The sealing body 23 is also provided with a gas discharge valve 28 that is opened when a gas pressure higher than the operating pressure of the current interrupt mechanism 27 is applied. Therefore, the inside of the nonaqueous electrolyte secondary battery 10 is sealed. The non-aqueous electrolyte secondary battery 10 is used in various applications singly or plurally connected in series or in parallel. When a plurality of the nonaqueous electrolyte secondary batteries 10 are connected in series or in parallel, a positive external terminal and a negative external terminal are separately provided and the batteries are connected by a bus bar. The flat wound electrode body 14 used in the rectangular nonaqueous electrolyte secondary battery 10 of Embodiment 1 is used for applications that require a high capacity and high output characteristics with a battery capacity of 20 Ah or more. For example, the number of windings of the positive electrode plate 11 is 43, that is, the total number of stacked positive electrode plates 11 is as large as 86.

  Thus, when the total number of laminated layers of the positive electrode core exposed portion 15 or the negative electrode core exposed portion 16 is large, the positive electrode current collector 17 is formed on the positive electrode core exposed portion 15 and the negative electrode current collector 19 is formed on the negative electrode core exposed portion 16. Are attached by resistance welding, a large welding current is required to form welding marks 15a, 16a penetrating over all the laminated portions of the positive electrode core exposed portion 15 or the negative electrode core exposed portion 16 which are stacked. is necessary.

  Therefore, as shown in FIGS. 2A to 2C, on the positive electrode plate 11 side, the plurality of stacked positive electrode core exposed portions 15 are divided into two, and a plurality of conductive positive electrode conductive members 29 are provided between them. Then, the positive electrode intermediate member 30 made of a resin material held by two is sandwiched. Similarly, on the negative electrode plate 12 side, a plurality of laminated negative electrode core exposed portions 16 are divided into two parts, and a negative electrode intermediate member 32 made of a resin material holding two conductive negative electrode conductive members 31 therebetween. Is sandwiched. The positive electrode current collectors 17 are disposed on the outermost surfaces on both sides of the positive electrode core exposed portion 15 located on both sides of the positive electrode conductive member 29, and the negative electrode located on both sides of the negative electrode conductive member 31. A negative electrode current collector 19 is disposed on each of the outermost surfaces of the core body exposed portion 16. The positive electrode conductive member 29 is made of aluminum, which is the same material as the positive electrode core, and the negative electrode conductive member 31 is made of copper, which is the same material as the negative electrode core, but the positive electrode conductive member 29 and the negative electrode conductive member. The shape of 31 may be the same or different.

  When the positive electrode core exposed portion 15 or the negative electrode core exposed portion 16 is divided into two in this way, a welding mark 15a that penetrates through all the laminated portions of the positive electrode core exposed portion 15 or the negative electrode core exposed portion 16 that are stacked. Since the welding current required for forming 16a is smaller than that in the case where it is not divided into two, the occurrence of spatter during resistance welding is suppressed, so that the internal short circuit of the wound electrode body 14 caused by spattering is suppressed. The occurrence of such troubles is suppressed. As described above, both the positive electrode current collector 17 and the positive electrode core body exposed portion 15 and the positive electrode core body exposed portion 15 and the positive electrode conductive member 29 are resistance-welded, and the negative electrode current collector 19 The negative electrode core exposed portion 16 and the negative electrode core exposed portion 16 and the negative electrode conductive member 31 are also connected by resistance welding. In FIG. 2, two welding marks 33 formed by resistance welding are shown on the positive electrode current collector 17, and two welding marks 34 are also shown on the negative electrode current collector 19. .

Hereinafter, the resistance welding method using the positive electrode intermediate member 30 having the positive electrode core exposed portion 15, the positive electrode current collector 17, and the positive electrode conductive member 29 in the flat wound electrode body 14 of Embodiment 1, and the negative electrode The resistance welding method using the negative electrode intermediate member 32 having the core exposed portion 16, the negative electrode current collector 19, and the negative electrode conductive member 31 will be described in detail. However, in the first embodiment, the shape of the positive electrode conductive member 29 and the positive electrode intermediate member 30 and the shape of the negative electrode conductive member 31 and the negative electrode intermediate member 32 can be substantially the same, and Since each resistance welding method is substantially the same, the following description will be made with the positive electrode plate 11 side as a representative.

  First, the positive electrode core exposed portion 15 of the flat wound electrode body 14 produced as described above is divided into two on both sides from the winding center portion, and the positive electrode core is centered on 1/4 of the electrode body thickness. The body exposed part 15 was collected. Then, the positive electrode current collector 17 having the positive electrode current collector 17 on both surfaces of the outermost peripheral side of the positive electrode core exposed portion 15 and the positive electrode conductive member 29 on the inner peripheral side, and the protrusions on both sides of the positive electrode conductive member 29 are Each was inserted between the positive electrode core exposed portions 15 divided into two so as to contact the positive electrode core exposed portions 15. The positive electrode current collector 17 is made of, for example, an aluminum plate having a thickness of 0.8 mm.

  Here, in the positive electrode conductive member 29 held by the positive electrode intermediate member 30 of the first embodiment, for example, a truncated cone-shaped projection (projection) is formed on each of two opposing surfaces of the cylindrical main body. . As the positive electrode conductive member 29, not only a cylindrical shape but also a metal block shape such as a prismatic shape or an elliptical column shape can be used. In addition, as a material for forming the positive electrode conductive member 29, a material made of copper, copper alloy, aluminum, aluminum alloy, tungsten, molybdenum, or the like can be used. The nickel-plated one, the protrusion and the vicinity of the root thereof are changed to a metal material that promotes heat generation such as tungsten or molybdenum, and the cylindrical positive electrode conductive member 29 made of copper, copper alloy, aluminum, or aluminum alloy What joined to the main body by brazing etc. can be used.

  Note that a plurality of, for example, two, positive electrode conductive members 29 are integrally held by a positive electrode intermediate member 30 made of a resin material. In this case, the respective positive electrode conductive members 29 are held in parallel with each other. The shape of the positive electrode intermediate member 30 can be an arbitrary shape such as a prismatic shape or a cylindrical shape, but in order to be stably positioned and fixed in the divided positive electrode core exposed portion 15. Is preferably a horizontally long prismatic shape. However, the corners of the positive electrode intermediate member 30 may be chamfered to prevent the positive electrode core exposed portion 15 from being scratched or deformed even if it contacts the soft positive electrode current collector exposed portion 12. preferable. The chamfered portion may be a portion that is inserted into the positive electrode core exposed portion 15 divided into at least two parts.

  The length of the prismatic positive electrode intermediate member 30 varies depending on the size of the prismatic nonaqueous electrolyte secondary battery 10, but can be 20 mm to several tens of mm. The width of the prismatic positive electrode intermediate member 30 may be approximately the same as the height of the positive electrode conductive member 29, but at least both ends of the positive electrode conductive member 29 serving as a welded portion may be exposed. . It is desirable that both ends of the positive electrode conductive member 29 protrude from the surface of the positive electrode intermediate member 30, but it does not necessarily have to protrude. With such a configuration, the positive electrode conductive member 29 is held by the positive electrode intermediate member 30, and the positive electrode intermediate member 30 is stably positioned between the two divided positive electrode core exposed portions 15. It is arranged in the state that was done.

Subsequently, the flat wound electrode body 14 in which the positive electrode intermediate member 30 holding the positive electrode current collector 17 and the positive electrode conductive member 29 is disposed between a pair of resistance welding electrodes (not shown) is disposed. These resistance welding electrodes are brought into contact with the positive electrode current collectors 17 arranged on both surfaces on the outermost peripheral side of the positive electrode core exposed portion 15. An appropriate pressure is applied between the pair of resistance welding electrodes, and resistance welding is performed under a predetermined condition. In this resistance welding, since the positive electrode intermediate member 30 is stably positioned between the two divided positive electrode core exposed portions 15, the positive electrode conductive member 29 and a pair of resistance welding members The dimensional accuracy between the electrodes is improved, resistance welding can be performed accurately and stably, and variations in welding strength are suppressed.

  Next, specific configurations of the positive electrode current collector 17 and the negative electrode current collector 19 according to Embodiment 1 will be described with reference to FIG. As shown in FIGS. 2A and 2B, the positive electrode current collector 17 is formed by resistance welding to a plurality of positive electrode core exposed portions 15 that are stacked on one side end face side of the flat wound electrode body 14. The positive electrode current collector 17 is electrically connected to the positive electrode terminal 18. Similarly, the negative electrode current collector 19 is electrically connected by resistance welding to a plurality of negative electrode core exposed portions 16 that are stacked on the other side end face side of the flat wound electrode body 14. The negative electrode current collector 19 is electrically connected to the negative electrode terminal 20.

  The positive electrode current collector 17 is manufactured, for example, by punching an aluminum plate into a predetermined shape and then bending it. In the positive electrode current collector 17, a rib 17 a is formed on a main body portion which is a portion where resistance welding is performed to the bundled positive electrode core exposed portion 15. The negative electrode current collector 19 is manufactured, for example, by punching a copper plate into a predetermined shape and then bending it. The negative electrode current collector 19 is also formed with a rib 19a on a main body portion which is a portion where resistance welding is performed to the bundled negative electrode core exposed portion 16.

  The rib 17a of the positive electrode current collector 17 and the rib 19a of the negative electrode current collector 19 both have a shielding role for preventing spatter generated during resistance welding from jumping into the flat wound electrode body 14. In addition, it has a role of a radiating fin for preventing portions other than the resistance welded portion of the positive electrode current collector 17 and the negative electrode current collector 19 from being melted by heat generated during resistance welding. The ribs 17a and 19a are provided vertically from the main bodies of the positive electrode current collector 17 and the negative electrode current collector 19, respectively. However, the ribs 17a and 19a are not necessarily vertical, and are inclined by about ± 10 ° from the vertical. Has the same effect.

  In the rectangular nonaqueous electrolyte secondary battery 10 of Embodiment 1, two ribs 17a of the positive electrode current collector 17 and ribs 19a of the negative electrode current collector 19 were provided in the length direction corresponding to the resistance welding positions. Although the example using a thing was shown, not only this but it is good also as one thing, and you may use the thing in which the rib is formed in the both sides of the width direction. In the case of using ribs formed on both sides in the width direction, both heights may be the same or different. If both heights are different, a flat wound electrode body It is preferable that the vicinity of 14 is higher.

  Further, in the rectangular nonaqueous electrolyte secondary battery 10 of the first embodiment, two welding connection positions of the positive electrode current collector 17 and the negative electrode current collector 19 with respect to the flat wound electrode body 14 are formed. These two welding connection positions are formed so as to straddle the winding center position CP. Therefore, in the region corresponding to the winding center position CP, the core exposed portions are not welded to each other, so that the non-aqueous electrolyte is supplied from the region corresponding to the winding center position CP to the central portion of the winding electrode body. Easy to enter.

[Production of positive electrode plate]
Next, the specific composition of the positive electrode active material mixture layer 11a and the negative electrode active material mixture layer 12a used in the rectangular nonaqueous electrolyte secondary battery 10 of Embodiment 1 and the specific composition of the nonaqueous electrolyte solution will be described. . As the positive electrode active material, a lithium nickel cobalt manganese composite oxide represented by LiNi _0.35 Co _0.35 Mn _0.30 O ₂ was used. The lithium nickel cobalt manganese composite oxide, carbon powder as a conductive agent, and polyvinylidene fluoride (PVdF) as a binder are weighed so that the mass ratio is 88: 9: 3, respectively, and used as a dispersion medium. A positive electrode active material mixture slurry was prepared by mixing with N-methyl-2-pyrrolidone (NMP). This positive electrode active material mixture slurry is applied to both surfaces of a positive electrode core made of, for example, a 15 μm thick aluminum foil by a die coater to form a positive electrode active material mixture layer on both surfaces of the positive electrode core, and then dried. Then, NMP as an organic solvent was removed and compressed to a predetermined thickness by a roll press. The obtained electrode plate was slit at one end in the width direction of the electrode plate so that a positive electrode core exposed portion 15 having a constant width over the entire length direction and having no positive electrode active material mixture layer formed on both surfaces was formed. The positive electrode plate 11 having the configuration shown in FIG. 3A was obtained.

[Production of negative electrode plate]
The negative electrode plate was produced as follows. A negative electrode active material mixture slurry was prepared by dispersing 98 parts by mass of graphite powder, 1 part by mass of carboxymethyl cellulose (CMC) as a thickener, and 1 part by mass of styrene-butadiene rubber (SBR) as a binder. This negative electrode active material mixture slurry was applied to both sides of a negative electrode current collector made of copper foil having a thickness of 10 μm by a die coater, dried to form a negative electrode active material mixture layer on both sides of the negative electrode current collector, Compressed to a predetermined thickness using a compression roller. Then, the negative electrode core exposed part 16 in which the negative electrode active material mixture layer is not formed on both sides with a constant width over the entire length direction is formed at one end in the width direction of the electrode plate. The negative electrode plate 12 having the structure shown in FIG. 3B was obtained by slitting.

[Preparation of non-aqueous electrolyte]
As a non-aqueous electrolyte, LiPF ₆ is used as an electrolyte salt in a mixed solvent in which ethylene carbonate (EC) and methyl ethyl carbonate (MEC) are mixed at a volume ratio (25 ° C., 1 atm) in a ratio of 3: 7. It was added to 1 mol / L, and LiBOB as a lithium salt having an oxalato complex as an anion was added to 0.1 mol / L and LiPF ₂ O ₂ to 0.05 mol / L. The added LiBOB reacts on the surface of the negative electrode plate during the initial charge to form a protective film, so that it is added to the nonaqueous electrolyte in the rectangular nonaqueous electrolyte secondary battery 10 of the first embodiment. Not all LiBOBs exist in the form of LiBOB. Similarly, LiPF ₂ O ₂ is also added to the nonaqueous electrolyte solution in the rectangular nonaqueous electrolyte secondary battery 10 of Embodiment 1 in order to form a protective film on the surfaces of the positive electrode and the negative electrode plate during the initial charge / discharge. are all LiPF ₂ O ₂ was not present in the form of LiPF ₂ O _2.

[Production of square nonaqueous electrolyte secondary battery]
The negative electrode plate 12 and the positive electrode plate 11 manufactured as described above are wound in a state of being insulated from each other via the separator 13 with the outermost surface side being the negative electrode plate 12, and then formed into a flat shape. Thus, a flat wound electrode body 14 was produced. In the flat wound electrode body 14, the number of turns of the positive electrode plate 11 and the negative electrode plate 12 is 43 times and 44 times, respectively, that is, the total number of stacked positive electrode plates 11 and negative electrode plates 12 is 86 pieces. 88, and the design capacity is 20 Ah. The total number of laminated positive electrode core exposed portions 15 and negative electrode core exposed portions 16 is 86 and 88, respectively. Using this flat wound electrode body 14, a rectangular nonaqueous electrolyte secondary battery into which a nonaqueous electrolyte was not injected was produced. Thereafter, the inside of the rectangular outer package 25 is vacuum degassed, and then a predetermined amount of the non-aqueous electrolyte prepared as described above is injected from the electrolyte solution injection port 26 provided in the sealing body 23. The liquid inlet 26 was sealed with a blind rivet, and the square nonaqueous electrolyte secondary battery 10 of Embodiment 1 having the configuration described in FIGS. 1 to 3 was produced. In addition, after injecting a nonaqueous electrolyte, it is preferable to perform a preliminary charge before sealing the electrolyte solution inlet 26.

  In the nonaqueous electrolyte secondary battery of Embodiment 1, since eight or more layers of only the separator are formed at the center of the flat wound electrode body, in the width direction of the flat wound electrode body. This is effective in improving the injection rate of the non-aqueous electrolyte.

In the prismatic nonaqueous electrolyte secondary battery 10 of the first embodiment, an example in which LiBOB is added as an additive to the nonaqueous electrolytic solution has been shown. However, in the present invention, lithium having an oxalato complex as an anion is shown. Other salts include lithium difluoro (oxalato) borate, lithium tris (oxalato) phosphate, lithium difluoro (bisoxalato) phosphate,
Lithium tetrafluoro (oxalato) phosphate and the like can also be used.

[Embodiment 2]
In the nonaqueous electrolyte secondary battery 10 of Embodiment 1 described above, the positive electrode core body exposed portion 15 and the negative electrode core body exposed portion 16 in which a plurality of sheets are laminated are each divided into two, and the positive electrode conductive member 29 or the negative electrode The example which has arrange | positioned the intermediate member 30 for positive electrodes thru | or the intermediate member 32 for negative electrodes which have the electrically-conductive member 31 was shown. However, in the present invention, the positive electrode core exposed portion 15 to the negative electrode core exposed portion 16 in which a plurality of sheets are laminated may not be divided into two.

  The stacked positive electrode core exposed portion 15 and the stacked negative electrode core exposed portion 16 are not divided into two, and the rectangular non-aqueous electrolyte 2 according to the second embodiment is configured such that the positive electrode conductive member and the negative electrode conductive member are not used. Next battery 10A will be described with reference to FIG. In FIG. 4, the same components as those of the rectangular nonaqueous electrolyte secondary battery 10 of Embodiment 1 shown in FIG. 2 are given the same reference numerals, and detailed descriptions thereof are omitted. Further, the configuration of the resistance welded portion between the positive electrode core exposed portion 15 and the positive electrode current collector 17 and the resistance between the negative electrode core exposed portion 16 and the negative electrode current collector 19 in the flat wound electrode body 14 of the second embodiment. Since the structure of the welded portion is substantially the same except that the respective forming materials are different, FIG. 4B illustrates a side view of the positive electrode core body exposed portion 15 side, and the negative electrode core body exposed portion 16 is illustrated. The side view of the side is not shown.

The flat wound electrode body 14 used in the rectangular nonaqueous electrolyte secondary battery 10A of the second embodiment is a flat wound as in the case of the rectangular nonaqueous electrolyte secondary battery 10 of the first embodiment. Eight layers of winding portions of only the separator are formed at the center of the rotating electrode body 14. Further, the positive electrode active material mixture layer 11a and the negative electrode active material mixture layer 12a per unit area in each of the positive electrode plate 11 and the negative electrode plate 12 are made larger than those in the first embodiment, and the positive electrode plate 11 and the negative electrode plate 12 are used. The number of windings is 35 and 36, respectively, that is, the total number of stacked positive and negative electrode plates 11 and 12 is 70 and 72, respectively, and the design capacity is 25 Ah. The total number of laminated positive electrode core exposed portions 15 and negative electrode core exposed portions 16 is 70 and 72, respectively. On the positive electrode plate 11 side, positive electrode current collectors 17 are disposed on the outermost surfaces on both sides of the plurality of positive electrode core exposed portions 15 stacked, and on the negative electrode side, a plurality of stacked negative electrodes A negative electrode current collector 19 is disposed on each of the outermost surfaces of the core body exposed portion 16. Then, resistance welding is performed at two locations so that welding marks (not shown) are formed so as to penetrate through all the laminated portions of the bundled positive electrode core exposed portion 15 to negative electrode core exposed portion 16. In FIG. 4, two welding marks 33 formed by resistance welding are shown on the positive electrode current collector 17, and two welding marks 34 are also shown on the negative electrode current collector 19. . In addition, ribs 15a formed on the positive electrode current collector 15 and ribs 16a formed on the negative electrode current collector 16 are formed across two resistance welding locations.

[Embodiment 3]
In the prismatic nonaqueous electrolyte secondary batteries 10 and 10A of Embodiments 1 and 2, two positive electrode current collectors 17 to 19 and two negative electrode current collectors 19 are attached to the bundled positive electrode core exposed portion 15 to negative electrode core exposed portion 16 respectively. Although the example which carried out the welding connection by carrying out resistance welding for every location was shown, this welding connection location may be one location. Therefore, a rectangular nonaqueous electrolyte secondary battery 10B according to the third embodiment in which the number of welds is one with respect to the rectangular nonaqueous electrolyte secondary battery 10A according to the second embodiment will be described with reference to FIG. In FIG. 5, the same components as those of the rectangular nonaqueous electrolyte secondary battery 10 </ b> A of Embodiment 2 shown in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted. Further, the configuration of the resistance welding portion between the positive electrode core exposed portion 15 and the positive electrode current collector 17 and the resistance between the negative electrode core exposed portion 16 and the negative electrode current collector 19 in the flat wound electrode body 14 of the third embodiment. The configuration of the welded portion is substantially the same except that the respective forming materials are different. Therefore, FIG. 5B illustrates a side view of the positive electrode core body exposed portion 15 side, and the negative electrode core body exposed portion 16 is illustrated. The side view of the side is not shown.

  The flat wound electrode body 14 used in the rectangular nonaqueous electrolyte secondary battery 10B of the third embodiment has the same configuration as that of the rectangular nonaqueous electrolyte secondary battery 10A of the second embodiment. On the positive electrode plate 11 side, the positive electrode current collectors 17 are sealed on the outermost surfaces on both sides of the plurality of stacked positive electrode core exposed portions 15 more than the center position CP of the flat wound electrode body 14. It is shifted to the body 23 side. Further, on the negative electrode plate 12 side, the negative electrode current collector 19 is disposed at the center position CP sealing body 23 of the flat wound electrode body 14 on both outermost surfaces of the plurality of laminated negative electrode core exposed portions 16. It is shifted to the side. Then, resistance welding is performed one by one so that welding marks (not shown) are formed so as to penetrate through all the laminated portions of the bundled positive electrode core exposed portion 15 to negative electrode core exposed portion 16. . In FIG. 5, a single welding mark 33 formed by resistance welding is shown on the positive electrode current collector 17, and a single welding mark 34 is also shown on the negative electrode current collector 19. .

  In the rectangular nonaqueous electrolyte secondary battery 10B of the third embodiment, the lower end portions (end portions on the side of the rectangular outer casing 25) of the positive electrode current collector 17 and the negative electrode current collector 19 are arranged at the center position CP of the wound electrode body 14. Since it is on the sealing body 23 side, the non-aqueous electrolyte solution can more easily enter the central portion of the wound electrode body 14. Note that the lower end of one of the positive electrode current collector 17 and the negative electrode current collector 19 may be closer to the sealing body 23 than the center position CP of the wound electrode body 14.

[Modification]
As a modification, an example in which negative electrode core exposed portions are formed at both ends in the width direction (short side direction) will be described with reference to FIG.

  In the non-aqueous electrolyte secondary batteries 10, 10 </ b> A, and 10 </ b> B shown in the first to third embodiments, the negative electrode core exposed portion 16 extends along the longitudinal direction at one end in the width direction of the negative electrode plate 12 as the negative electrode plate 12. What is formed is used (not shown). As shown in FIG. 6, the negative electrode plate 12 </ b> A of the modified example has another negative electrode core with a constant width along the longitudinal direction on the side opposite to the side where the negative electrode core exposed part 16 in the width direction is formed. The exposed portion 16b is formed on both sides. The negative electrode core exposed portion 16 b is formed on both surfaces of the negative electrode plate 12. The positive electrode plate 11 has the same size and the same configuration (not shown) as the normal positive electrode plate 11 used in the nonaqueous electrolyte secondary batteries 10, 10 </ b> A, and 10 </ b> B shown in the first to third embodiments. use.

  If the negative electrode plate 12A having such a configuration is used, the heat generated in the flat wound electrode body 14 can be easily radiated from both ends in the width direction of the negative electrode core exposed portions 16 and 16b, and the flat The temperature rise inside the wound electrode body 14 is suppressed.

  In this case, the surface of the negative electrode active material mixture layer 12a, the surface of the newly formed negative electrode core exposed portion 16b, and a part along the formation portion of the negative electrode active material mixture layer 12a of the negative electrode core exposed portion 16 Moreover, it is preferable to form a protective layer 16c (shaded portion in FIG. 6) made of metal oxide particles and a binder on both sides. Note that alumina, titania, zirconia, or the like is preferably used as the metal oxide, and an acrylate resin is preferably used as the binder.

  With such a configuration, the protective layer 16c is porous and insulative due to the presence of the metal oxide particles, so the negative electrode plate 12 and the separator in the flat wound electrode body 14 13 is a state in which a minute gap is generated, and the non-aqueous electrolyte easily penetrates into the central portion of the flat wound electrode body 14. In addition, since the insulating property between the newly formed negative electrode core exposed portion 16b and the positive electrode core exposed portion 15 on the side facing the positive electrode core exposed portion 15 via the separator 13 is improved, the reliability is improved. A nonaqueous electrolyte secondary battery excellent in performance can be obtained.

In the square nonaqueous electrolyte secondary batteries 10, 10 </ b> A, and 10 </ b> B of Embodiments 1 to 3 described above, the example in which the configuration for shifting the welded portion is provided on both the positive electrode plate 11 side and the negative electrode plate 12 side is shown. It may be provided only on the plate 11 side or only on the negative electrode plate 12 side. In the non-aqueous electrolyte secondary batteries 10, 10 </ b> A, and 10 </ b> B of Embodiments 1 to 3 above, lithium salt and LiPF ₂ O ₂ having an oxalato complex such as LiBOB as an anion are added to the non-aqueous electrolyte. However, when the present invention is applied to the case where the viscosity of the nonaqueous electrolytic solution is increased, a good effect can be obtained. Therefore, even when only a lithium salt having an oxalato complex as an anion or only LiPF ₂ O ₂ is contained, the viscosity of the nonaqueous electrolytic solution is increased, and therefore, it can be similarly applied.

  In the first to third embodiments and the prismatic nonaqueous electrolyte secondary battery according to the modification, the positive electrode core exposed portion 15 and the positive electrode current collector 17 and the negative electrode core exposed portion 16 and the negative electrode current collector are provided. Although the example which connected between 19 each by resistance welding was shown, you may connect by irradiation of high energy rays, such as ultrasonic welding and a laser. Further, different connection methods can be used on the positive electrode side and the negative electrode side.

DESCRIPTION OF SYMBOLS 10, 10A, 10B ... Non-aqueous electrolyte secondary battery 11 ... Positive electrode plate 11a ... Positive electrode active material mixture layer 11b ... Positive electrode core 12 ... Negative electrode plate 12a ... Negative electrode active material mixture layer 12b ... Negative electrode core 13 ... Separator 14 DESCRIPTION OF SYMBOLS ... Winding electrode body 15 ... Positive electrode core exposure part 15a ... Welding trace 16, 16b ... Negative electrode core exposure part 16a ... Welding trace 16c ... Protective layer 17 ... Positive electrode collector 17a ... Rib 18 ... Positive electrode terminal 19 ... Negative electrode collection Electrical body 19a ... Rib 20 ... Negative electrode terminal 21, 22 ... Insulating member 23 ... Sealing body 24 ... Resin sheet 25 ... Rectangular exterior body 26 ... Electrolyte injection port 27 ... Current interruption mechanism 28 ... Gas discharge valve 29 ... Conductivity for positive electrode Member 30 ... Intermediate member for positive electrode 31 ... Conductive member for negative electrode 32 ... Intermediate member for negative electrode 33, 34 ... Trace of welding CP ... Center position of winding

Claims (12)

A flat wound electrode body obtained by winding a long positive electrode plate and a long negative electrode plate through a long separator;
An exterior body having an opening and a bottom and accommodating the flat wound electrode body and the non-aqueous electrolyte; and
A sealing body for sealing the opening,
There are 8 or more layers of only the separator in the center of the flat wound electrode body,
A positive electrode core exposed portion is formed along the longitudinal direction of the positive electrode plate,
A negative electrode core exposed portion is formed along the longitudinal direction of the negative electrode plate,
The flat wound electrode body has a positive electrode core exposed portion wound around one end, and a negative electrode core exposed portion wound around the other end.
A current collector is welded to at least one of the positive electrode core exposed portion and the negative electrode core exposed portion,
The welded portion of the current collector is a method for producing a nonaqueous electrolyte secondary battery that is offset from a winding center axis of the flat wound electrode body,
Connecting at least one of the positive electrode core exposed portion and the negative electrode core exposed portion with the current collector by ultrasonic welding; and
A method for producing a nonaqueous electrolyte secondary battery, comprising a step of injecting a nonaqueous electrolyte solution containing at least one of a lithium salt having an oxalato complex as an anion and lithium difluorophosphate (LiPF ₂ O ₂ ) into the outer package. A flat wound electrode body obtained by winding a long positive electrode plate and a long negative electrode plate through a long separator;
An exterior body having an opening and a bottom and accommodating the flat wound electrode body and the non-aqueous electrolyte; and
A sealing body for sealing the opening,
There are 8 or more layers of only the separator in the center of the flat wound electrode body,
A positive electrode core exposed portion is formed along the longitudinal direction of the positive electrode plate,
A negative electrode core exposed portion is formed along the longitudinal direction of the negative electrode plate,
The flat wound electrode body has a positive electrode core exposed portion wound around one end, and a negative electrode core exposed portion wound around the other end.
A current collector is welded to at least one of the positive electrode core exposed portion and the negative electrode core exposed portion,
The welded portion of the current collector is a method for producing a nonaqueous electrolyte secondary battery that is offset from a winding center axis of the flat wound electrode body,
At least one of the wound positive electrode core exposed portion and the wound negative electrode core exposed portion,
In the stacking direction of the positive electrode core exposed portion or the negative electrode core exposed portion, the step of bundling all of the positive electrode core exposed portion or the negative electrode core exposed portion together and connecting to the current collector;
A method for producing a nonaqueous electrolyte secondary battery, comprising a step of injecting a nonaqueous electrolyte solution containing at least one of a lithium salt having an oxalato complex as an anion and lithium difluorophosphate (LiPF ₂ O ₂ ) into the outer package.   In a direction perpendicular to the bottom, the distance from the end on the sealing body side of the flat wound electrode body to the end on the bottom side of the current collector is the bottom side of the current collector The manufacturing method of the nonaqueous electrolyte secondary battery of Claim 1 or 2 smaller than the distance from the edge part of this to the edge part on the said bottom part side of the said flat winding electrode body. A flat wound electrode body obtained by winding a long positive electrode plate and a long negative electrode plate through a long separator;
An exterior body having an opening and a bottom and accommodating the flat wound electrode body and the non-aqueous electrolyte; and
A sealing body for sealing the opening,
There are 8 or more layers of only the separator in the center of the flat wound electrode body,
A positive electrode core exposed portion is formed along the longitudinal direction of the positive electrode plate,
A negative electrode core exposed portion is formed along the longitudinal direction of the negative electrode plate,
The flat wound electrode body has a positive electrode core exposed portion wound around one end, and a negative electrode core exposed portion wound around the other end.
A current collector is welded to at least one of the positive electrode core exposed portion and the negative electrode core exposed portion,
The welded portion of the current collector is offset from the winding center axis of the flat wound electrode body,
In a direction perpendicular to the bottom, the distance from the end on the sealing body side of the flat wound electrode body to the end on the bottom side of the current collector is the bottom side of the current collector A non-aqueous electrolyte secondary battery manufacturing method smaller than the distance from the end of the flat wound electrode body to the end on the bottom side of the flat wound electrode body,
A method for producing a nonaqueous electrolyte secondary battery, comprising a step of injecting a nonaqueous electrolyte solution containing at least one of a lithium salt having an oxalato complex as an anion and lithium difluorophosphate (LiPF ₂ O ₂ ) into the outer package. At least one of the wound positive electrode core exposed portion and the wound negative electrode core exposed portion is:
A first region where the stacked positive electrode core exposed portion or the stacked negative electrode core exposed portion is bundled in the stacking direction and the current collector is connected;
A second region having a thickness larger than the thickness of the first region in the stacking direction and disposed closer to the sealing body than the first region;
A third region having a thickness greater than the thickness of the first region in the stacking direction and disposed on the bottom side of the first region;
The manufacturing method of the nonaqueous electrolyte secondary battery in any one of Claims 1-4 which have these. At the time of producing the non-aqueous electrolyte secondary battery, the non-aqueous electrolyte includes at least a lithium salt having the oxalato complex as an anion, and a content of the lithium salt having the oxalato complex as an anion in the non-aqueous electrolyte is 0.01 to 2.0 mol / L,
Or
At the time of manufacturing the non-aqueous electrolyte secondary battery, the non-aqueous electrolyte contains at least the lithium difluorophosphate, and the content of the lithium difluorophosphate in the non-aqueous electrolyte is 0.00.
01-2.0 mol / L,
The manufacturing method of the nonaqueous electrolyte secondary battery in any one of Claims 1-5. A flat wound electrode body obtained by winding a long positive electrode plate and a long negative electrode plate through a long separator;
An exterior body having an opening and a bottom and accommodating the flat wound electrode body and the non-aqueous electrolyte; and
A sealing body for sealing the opening ,
Windings of the separator only occur more than eight layers in the central portion of the front SL flat wound electrode assembly,
A positive electrode core exposed portion in which a positive electrode active material mixture layer is not formed on the surface of the positive electrode core along the longitudinal direction is formed on the positive electrode plate,
A negative electrode core exposed portion in which a negative electrode active material mixture layer is not formed on the surface of the negative electrode core is formed along the longitudinal direction at both ends in the width direction of the negative electrode plate,
The flat wound electrode body has a positive electrode core exposed portion wound around one end, and a negative electrode core exposed portion wound around the other end.
A method for producing a non-aqueous electrolyte secondary battery in which a current collector is welded to at least one of the positive electrode core exposed portion and the negative electrode core exposed portion,
Connecting at least one of the positive electrode core exposed portion and the negative electrode core exposed portion with the current collector by ultrasonic welding; and
A method for producing a nonaqueous electrolyte secondary battery, comprising a step of injecting a nonaqueous electrolyte solution containing at least one of a lithium salt having an oxalato complex as an anion and lithium difluorophosphate (LiPF ₂ O ₂ ) into the outer package. A flat wound electrode body obtained by winding a long positive electrode plate and a long negative electrode plate through a long separator;
An exterior body having an opening and a bottom and accommodating the flat wound electrode body and the non-aqueous electrolyte; and
A sealing body for sealing the opening ,
Windings of the separator only occur more than eight layers in the central portion of the front SL flat wound electrode assembly,
A positive electrode core exposed portion in which a positive electrode active material mixture layer is not formed on the surface of the positive electrode core along the longitudinal direction is formed on the positive electrode plate,
A negative electrode core exposed portion in which a negative electrode active material mixture layer is not formed on the surface of the negative electrode core is formed along the longitudinal direction at both ends in the width direction of the negative electrode plate,
The flat wound electrode body has a positive electrode core exposed portion wound around one end, and a negative electrode core exposed portion wound around the other end.
A method for producing a non-aqueous electrolyte secondary battery in which a current collector is welded to at least one of the positive electrode core exposed portion and the negative electrode core exposed portion,
At least one of the wound positive electrode core exposed portion and the wound negative electrode core exposed portion,
In the stacking direction of the positive electrode core exposed portion or the negative electrode core exposed portion, the step of bundling all of the positive electrode core exposed portion or the negative electrode core exposed portion together and connecting to the current collector;
A method for producing a nonaqueous electrolyte secondary battery, comprising a step of injecting a nonaqueous electrolyte solution containing at least one of a lithium salt having an oxalato complex as an anion and lithium difluorophosphate (LiPF ₂ O ₂ ) into the outer package.   In a direction perpendicular to the bottom, the distance from the end on the sealing body side of the flat wound electrode body to the end on the bottom side of the current collector is the bottom side of the current collector The manufacturing method of the nonaqueous electrolyte secondary battery of Claim 7 or 8 smaller than the distance from the edge part of this to the edge part on the said bottom part side of the said flat winding electrode body. A flat wound electrode body obtained by winding a long positive electrode plate and a long negative electrode plate through a long separator;
An exterior body having an opening and a bottom and accommodating the flat wound electrode body and the non-aqueous electrolyte; and
A sealing body for sealing the opening ,
Windings of the separator only occur more than eight layers in the central portion of the front SL flat wound electrode assembly,
A positive electrode core exposed portion in which a positive electrode active material mixture layer is not formed on the surface of the positive electrode core along the longitudinal direction is formed on the positive electrode plate,
A negative electrode core exposed portion in which a negative electrode active material mixture layer is not formed on the surface of the negative electrode core is formed along the longitudinal direction at both ends in the width direction of the negative electrode plate,
The flat wound electrode body has a positive electrode core exposed portion wound around one end, and a negative electrode core exposed portion wound around the other end.
A current collector is welded to at least one of the positive electrode core exposed portion and the negative electrode core exposed portion,
In a direction perpendicular to the bottom, the distance from the end on the sealing body side of the flat wound electrode body to the end on the bottom side of the current collector is the bottom side of the current collector A non-aqueous electrolyte secondary battery manufacturing method smaller than the distance from the end of the flat wound electrode body to the end on the bottom side of the flat wound electrode body,
A method for producing a nonaqueous electrolyte secondary battery, comprising a step of injecting a nonaqueous electrolyte solution containing at least one of a lithium salt having an oxalato complex as an anion and lithium difluorophosphate (LiPF ₂ O ₂ ) into the outer package. At least one of the wound positive electrode core exposed portion and the wound negative electrode core exposed portion is:
A first region where the stacked positive electrode core exposed portion or the stacked negative electrode core exposed portion is bundled in the stacking direction and the current collector is connected;
A second region having a thickness larger than the thickness of the first region in the stacking direction and disposed closer to the sealing body than the first region;
A third region having a thickness greater than the thickness of the first region in the stacking direction and disposed on the bottom side of the first region;
The manufacturing method of the nonaqueous electrolyte secondary battery in any one of Claims 7-10 which has these. At the time of producing the non-aqueous electrolyte secondary battery, the non-aqueous electrolyte includes at least a lithium salt having the oxalato complex as an anion, and a content of the lithium salt having the oxalato complex as an anion in the non-aqueous electrolyte is 0.01 to 2.0 mol / L,
Or
At the time of producing the non-aqueous electrolyte secondary battery, the non-aqueous electrolyte includes at least the lithium difluorophosphate, and the content of the lithium difluorophosphate in the non-aqueous electrolyte is 0.01 to 2.0 mol / L,
The manufacturing method of the nonaqueous electrolyte secondary battery in any one of Claims 7-11.