JP5380908B2 - Winding electrode body and non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to a wound electrode body formed by winding a positive electrode and a negative electrode through a separator, and a nonaqueous electrolyte secondary battery using the same.

  2. Description of the Related Art Conventionally, many portable electronic devices such as a camera-integrated VTR (videotape recorder), a mobile phone, and a portable computer have appeared, and their size and weight have been reduced. Accordingly, the development of batteries, particularly secondary batteries, has been actively promoted as portable power sources for electronic devices. Among these, lithium ion secondary batteries are attracting attention as being capable of realizing a high energy density.

As such a lithium ion secondary battery, there is a conventional type in which a metal battery can such as aluminum (Al) or iron (Fe) is used as an exterior member, and a power generation element is sealed together with an electrolytic solution. .
In recent years, a type in which a laminate film is used as an exterior member instead of a metal battery can, a solid gel electrolyte is used, and a power generation element is sealed with a laminate film has been developed.

A lithium ion secondary battery using a laminate film as an exterior member is more advantageous than a lithium ion battery using a battery can in terms of reducing the size, weight and capacity of the battery. Since the solid gel electrolyte is isolated, there is an advantage that safety against abnormal use conditions such as overcharge is excellent.
However, if the gel electrolyte placed between the positive electrode and the negative electrode of the lithium ion secondary battery has a defect, or if the gel electrolyte has a non-uniform thickness, it will be Resistance may be significantly reduced.

In order to keep the electrode plate interval (the thickness of the gel electrolyte) between the positive electrode and the negative electrode constant, for example, Patent Document 1 discloses a power generation element formed by winding a positive electrode plate, a separator, and a negative electrode plate in a bag shape. In a non-aqueous electrolyte secondary battery housed in a single battery case, as a power generation element, a positive electrode terminal projecting in one direction in the longitudinal direction (winding axis direction) of the power generation element from one side wall parallel to the central axis of the power generation element And a negative electrode terminal are disclosed that are fixed with a winding tape over the circumference of the power generation element (Patent Document 1).
Further, in Patent Document 2, a non-aqueous electrolyte secondary battery in which a power generation element formed by winding a positive electrode plate, a separator, and a negative electrode plate is accommodated in a bag-shaped single battery case, the central axis of the power generation element is used as the power generation element. From one side wall parallel to the first power winding element, passing between the positive electrode terminal and the negative electrode terminal protruding in one direction of the longitudinal direction (winding axis direction) of the power generation element, It is fixed with a stop tape and is fixed with a second stop tape from the lateral direction over the circumference of the power generating element so as to be orthogonal to the longitudinal stop tape (Patent Document 2). ).
JP 2000-277162 A JP 2001-185224 A

However, since the power generation elements disclosed in Patent Documents 1 and 2 are wound around the circumference of the power generation element with a winding tape, the thickness of the portion fixed with the winding tape is larger than that of other portions. Also thicken.
For example, in the power generation element of Patent Document 1, the portion fixed by the winding tape is thicker than the other portion by twice the thickness of the winding tape. Further, in the power generation element of Patent Document 2, the portion where the first winding tape and the second winding tape fixed so as to be orthogonal to each other in the vertical direction and the horizontal direction overlap with the thickness of the winding tape more than other portions. It will be 4 times thicker.

  By the way, since the gel electrolyte which comprises the power generation element of a nonaqueous electrolyte secondary battery and is interposed between the positive electrode and the negative electrode is made of a relatively soft material, the gel electrolyte is used as the positive electrode, the negative electrode, and the separator. When the power generation element is pressurized in a vacuum state in order to make it closely contact, the gel electrolyte in the thick part tends to escape to the small thickness part and tends to make the thickness of the entire power generation element uniform. Therefore, as in Patent Documents 1 and 2, if the thickness of the power generation element is not uniform, the gel electrolyte of the power generation element becomes non-uniform when pressed in a vacuum state, so There is a tendency that the thickness of the gel electrolyte in the portion fixed with the tape becomes thin.

When a power generation element having a non-uniform gel electrolyte thickness is used in a non-aqueous electrolyte secondary battery, the non-aqueous electrolyte secondary battery has an internal electrical resistance due to the difference in the thickness of the gel electrolyte. Differences in height can be made, and repeated charge / discharge results in a difference in discharge, which degrades cycle characteristics.
In addition, if a power generation element with a non-uniform gel electrolyte thickness is used for a non-aqueous electrolyte secondary battery, the non-aqueous electrolyte secondary battery will have a thin portion of the gel electrolyte when an abnormality such as an external short circuit occurs. In some cases, a large amount of current flows to cause thermal runaway.

  The present invention has been made paying attention to the above-described conventional problems, and makes the thickness of the gel electrolyte as uniform as possible, uniforming electric resistance, improving cycle characteristics and energy density, It is an object of the present invention to provide a wound electrode body and a non-aqueous electrolyte secondary battery in which safety is improved by suppressing thermal runaway at the time.

  As a result of intensive studies to achieve the above-mentioned object, the inventors of the present invention have found that the fixing tape that fixes the outermost peripheral edge around which the positive electrode, the negative electrode, and the separator are fixed is formed into a flat-shaped wound electrode body. The present inventors have found that the above object can be achieved by the presence of the flat surface in a position that does not overlap with the positive electrode terminal and the negative electrode terminal in plan view, and the present invention has been completed.

That is, the wound electrode body of the present invention includes a strip-shaped positive electrode and a negative electrode, a strip-shaped separator interposed between the positive electrode and the negative electrode, connected to the positive electrode, and the positive electrode, the negative electrode, and the separator stacked. A flat plate-like positive electrode terminal protruding along the wound winding axis direction; and a flat plate-like negative electrode terminal connected to the negative electrode and protruding along the winding axis direction. A fixing tape that fixes the outermost peripheral ends of the positive electrode, the negative electrode, and the separator wound so that a cross section perpendicular to the axis has a flat shape having a major axis and a minor axis around the winding axis, It exists only on one flat surface of two flat surfaces facing the main surface of the flat positive electrode terminal and / or negative electrode terminal, and the winding axis direction of the positive electrode terminal and the negative electrode terminal in plan view position that does not overlap with the positive and negative terminals so as to face the end It is present, between at least one and the separator of the positive electrode and the negative electrode, in which an electrolytic solution is interposed a polymeric support layer made by supporting the polymer.

  Moreover, the nonaqueous electrolyte secondary battery of the present invention comprises the above wound electrode body, a nonaqueous electrolyte solution, and an exterior body that accommodates the above wound electrode body and the nonaqueous electrolyte solution.

  According to the present invention, the fixing tape that fixes the outermost peripheral end portion of the wound electrode body is wound so that the positive electrode, the negative electrode, and the separator are overlapped so that the cross section perpendicular to the winding axis direction has a flat shape. The wound wound electrode body is on one flat surface facing the main surface of the flat plate-like positive electrode terminal and / or negative electrode terminal, and is present at a position that does not overlap the positive electrode terminal and the negative electrode terminal in plan view. As a result, the thickness of the gel electrolyte existing between the two opposing flat surfaces of the wound electrode body is made substantially uniform, the electric resistance is made uniform, the cycle characteristics and the energy density are improved, and abnormal It is possible to provide a wound electrode body and a non-aqueous electrolyte secondary battery that are improved in safety by suppressing thermal runaway at the time.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is an exploded perspective view showing a first example of a preferred embodiment of the nonaqueous electrolyte secondary battery of the present invention.
As shown in FIG. 1, in the nonaqueous electrolyte secondary battery 10 of this example, a wound electrode body (winding battery element) 20 to which a positive electrode terminal 11 and a negative electrode terminal 12 are attached is formed with a bathtub-shaped recess. An exterior member 30A and a rectangular exterior member 30B disposed opposite to a bathtub-shaped recess of the exterior member 30A are enclosed in an exterior body 30.
The positive electrode terminal 11 and the negative electrode terminal 12 are led out in the same direction in this example from the inside of the exterior body 30 toward the outside. The positive electrode terminal 11 and the negative electrode terminal 12 are each made of a metal material such as aluminum (Al), copper (Cu), nickel (Ni), or stainless steel.
The positive electrode terminal 11 and the negative electrode terminal 12 were each a flat plate having a thickness of 40 to 100 μm. In the flat positive electrode terminal (or negative electrode terminal), the main surface of the positive electrode terminal (or negative electrode terminal) means the plane having the largest area among the flat surfaces constituting the flat plate positive electrode terminal (or negative electrode terminal). To do.
In the nonaqueous electrolyte secondary battery described later, the positive electrode terminal and the negative electrode terminal having the same material and thickness as the positive electrode terminal and the negative electrode terminal were used.

  An adhesion film 31 for preventing intrusion of outside air is inserted between the exterior members 30 </ b> A and 30 </ b> B and the positive electrode terminal 11 and the negative electrode terminal 12. The adhesion film 31 is made of a material having adhesion to the positive electrode terminal 11 and the negative electrode terminal 12. For example, when the positive electrode terminal 11 and the negative electrode terminal 12 are made of the above metal material, polyethylene, polypropylene, modified It is preferably composed of a polyolefin resin such as polyethylene or modified polypropylene.

FIG. 2 is a schematic cross-sectional view taken along an imaginary line II-II of the spirally wound electrode body illustrated in FIG.
In FIG. 2, a wound electrode body (wound battery element) 20 has a configuration in which a positive electrode 21 and a negative electrode 22 are disposed so as to face each other with a polymer support layer 23 and a separator 24 interposed therebetween. doing. In addition, in FIG. 2, although the cross section orthogonal to a winding axis shows the winding electrode body which becomes a rectangular shape typically, it is not only this example but orthogonal to a winding axis as shown in FIG. The cross section may be an ellipse having a major axis and a minor axis with the winding axis as the center, and the opposing part of the wound electrode body in which the cross section perpendicular to the winding axis is an ellipse is 2 You may form so that it may become two flat surfaces.
As shown in FIG. 2, in the wound electrode body 20, a polymer support layer 23 and a separator 24 are fixed to a take-up shaft (not shown), and the polymer support layer 23 and the separator 24 are fixed to the take-up shaft. Between them, the positive electrode 21 or the negative electrode 22 is inserted, and it has the structure wound by the state where four layers were laminated | stacked.
Note that the winding shaft is removed after winding. In this specification, the axis center of the wound electrode body from which the winding shaft is removed is referred to as a wound body axis.
The starting end of the positive electrode 21 or the negative electrode 22 is protected by protective tapes 25a and 25b. Note that the thickness of the protective tapes 25a and 25b is 15 to 35 μm, and the presence of the protective tape hardly affects the thickness of the wound electrode body and the gel electrolyte. In the nonaqueous electrolyte secondary battery described later, the same protective tape as the protective tape was used.

FIG. 3 is a plan view of the nonaqueous electrolyte secondary battery 10 shown in FIG.
The wound electrode body 20 has a structure in which at least one of the positive electrode 21, the negative electrode 22, and the separator 24 that constitutes the outermost peripheral end portion of the wound electrode body 20 is fixed with a fixing tape (winding tape) 26 </ b> A. ing.
The fixing tape (winding tape) has a thickness of 40 to 100 μm.
Further, as the fixing tape, for example, a tape-like base material made of polypropylene, for example, having an acrylic adhesive applied as an adhesive can be used. In the nonaqueous electrolyte secondary battery described later, a fixing tape having the same material and thickness as the fixing tape was used.

As shown in FIG. 3, the wound electrode body 20 includes a winding tape 26 </ b> A that fixes the outermost peripheral end of the wound electrode body, facing the main surface of the flat plate-like positive electrode terminal and / or negative electrode terminal. It has a structure that is on one flat surface of the rotating electrode body 20 and is present at a position that does not overlap the positive electrode terminal 11 and the negative electrode terminal 12 in plan view.
In the present specification, the flat surface of the wound electrode body means that a surface having a curvature is also included. For example, the cross-sectional shape orthogonal to the winding axis direction of the wound electrode body is an elliptical shape, and the surface having a convex bulge in the external direction of the wound electrode body is also included in the flat surface of the wound electrode body Shall be.

In the present specification, the polymer support layer means a layer formed by supporting an electrolytic solution on a polymer.
Examples of the polymer support layer of the wound electrode body 20 include a polymer (polymer) layer containing an electrolytic solution formed between at least one of the positive electrode 21 and the negative electrode 22 and the separator 24.
Further, as the polymer support layer of the wound electrode body 20, a polymer (polymer) layer not containing an electrolytic solution is formed between at least one of the positive electrode 21 and the negative electrode 22 and the separator 24, and the positive electrode 21, The negative electrode 22, the separator, and the polymer (polymer) layer are stacked and wound, and the wound material is sealed in the exterior body 30 composed of the exterior members 30A and 30B, and an electrolytic solution containing a monomer is injected into the exterior body 30, Examples include those in which a monomer contained in an electrolytic solution is polymerized and the electrolytic solution is supported by a polymer (polymer) layer.

Among the members constituting the nonaqueous electrolyte secondary battery 10, the positive electrode terminal 11, the negative electrode terminal 12, and the fixing tape 26A each have a large thickness of 40 to 100 μm.
Therefore, in the wound electrode body, when the positive electrode terminal 11, the negative electrode terminal 12, and the fixing tape 26A are present at positions where they overlap each other in plan view, the wound electrode body has a portion where these members exist, Thicker than the part. When such a wound electrode body is subjected to vacuum pressurization or the like, the gel-like polymer support layer 23 existing in the thick portion escapes to the small thickness portion, and the thickness of the gel electrolyte is increased. May become uneven.

  In the nonaqueous electrolyte secondary battery 10 of this example, the positive electrode terminal 11, the negative electrode terminal 12, and the fixing tape 26 </ b> A having relatively large thickness among the members constituting the wound electrode body 20 are all viewed from above. Therefore, the thickness between the two flat surfaces facing each other of the spirally wound electrode body 20 can be made substantially uniform, and the polymer support layer 23 that is gelled by the electrolytic solution. Can be made uniform in thickness.

In this way, when the thickness between the two flat surfaces facing each other of the wound electrode body 20 is substantially uniform, the non-aqueous electrolyte secondary battery formed by pressurization using the wound electrode body 20 10 can make the thickness of the polymer support layer (gel electrolyte) 23 gelled by the electrolytic solution uniform.
As a result, the non-aqueous electrolyte secondary battery 10 using the wound electrode body 20 of this example can suppress the difference in height of the electrical resistance and can improve the cycle characteristics.
Further, when the thickness of the gel electrolyte layer of the nonaqueous electrolyte secondary battery 10 is made uniform, the energy density of the nonaqueous electrolyte secondary battery can be improved.
In addition, since the non-aqueous electrolyte secondary battery 10 of this example has a uniform thickness of the gel electrolyte layer, the internal resistance of the battery can be made uniform, and the resistance is small when an abnormality such as an external short circuit occurs. Since a large amount of current does not flow specifically in the portion, safety can be improved.

Next, another example of a preferred embodiment of the nonaqueous electrolyte secondary battery of the present invention will be described.
FIG. 4 is a plan view showing a second example of a preferred embodiment of the nonaqueous electrolyte secondary battery of the present invention. FIG. 5 is a schematic cross-sectional view taken along the phantom line II-II of the nonaqueous electrolyte secondary battery shown in FIG. The II-II imaginary line is symmetrical with one flat plane of the wound electrode body 20 formed so that the cross section perpendicular to the winding axis direction has a flat shape having a major axis and a minor axis with the winding axis as the center. It is a line that passes through the center point C and extends in a direction (lateral direction) orthogonal to the wound body axis direction. 4 and 5, the same members as those in the nonaqueous electrolyte secondary battery in FIGS.
In the present specification, the symmetrical center point C of the wound electrode body is formed such that a cross section perpendicular to the winding axis direction has a flat shape having a major axis and a minor axis about the winding axis. It refers to the symmetrical center point C of the shape constituting one flat surface of the wound electrode body 20, and when one flat surface is a quadrangle, the center point between one side and the other side of the quadrilateral Say.
As shown in FIG. 4, the non-aqueous electrolyte secondary battery 10B of this example includes a short positive electrode terminal 11B and a negative electrode terminal 12B that do not reach the II-II imaginary line passing through the symmetry center point C of the wound electrode body 20B. I have.

As shown in FIGS. 4 and 5, the wound electrode body 20 </ b> B of this example is formed by fixing a fixing tape 26 </ b> B with the outermost peripheral end portion of the wound electrode body 20 </ b> B fixed in a cross section perpendicular to the winding axis direction. On one flat plane of the wound electrode body 20B formed so as to have a flat shape having a major axis and a minor axis with the axis as a center, a symmetrical center point C of the shape constituting the flat plane is included, and is seen in a plan view Thus, the positive electrode terminal 11B and the negative electrode terminal 12B are not overlapped with each other.
In the wound electrode body 20B of this example, the fixing tape 26B is an area (rectangular shape) that spreads substantially uniformly on the one flat surface of the wound electrode body 20B around the symmetry center point C of the flat surface. Therefore, the thickness between the two flat surfaces facing each other of the spirally wound electrode body 20 is substantially uniform, and the thickness of the polymer support layer 23 that is gelled by the electrolytic solution is made uniform. can do.

FIG. 6 is a plan view showing a first example of a preferred reference embodiment of the nonaqueous electrolyte secondary battery of the present invention. FIG. 7 is a schematic cross-sectional view taken along an imaginary line II-II of the nonaqueous electrolyte secondary battery shown in FIG. The II-II imaginary line passes through the symmetrical center point C of the wound electrode body 20C formed so that the cross section perpendicular to the winding axis direction has a flat shape having a major axis and a minor axis about the winding axis. And it is a line extended in the direction (horizontal direction) orthogonal to a wound body axial direction. 6 and 7, the same members as those of the nonaqueous electrolyte secondary battery of FIGS.
As shown in FIGS. 6 and 7, the nonaqueous electrolyte secondary battery 10C of this example includes a positive electrode terminal 11C and a negative electrode having a length exceeding the II-II imaginary line passing through the symmetry center point C of the wound electrode body 20C. A terminal 12C is provided.

As shown in FIGS. 6 and 7, the wound electrode body 20 </ b> C includes a fixing tape 26 </ b> C that fixes the outermost peripheral end of the wound electrode body 20 </ b> C, and a cross section perpendicular to the winding axis direction is centered on the winding axis. As a flat terminal of a spirally wound electrode body 20C formed so as to have a flat shape having a major axis and a minor axis. 11B and the negative electrode terminal 12B.
In the wound electrode body 20C of this example, the positive electrode terminal 11C, the fixing tape 26C, and the negative electrode terminal 12C, which are relatively thick members, are arranged in parallel in the axial direction (longitudinal direction) of the wound body in plan view. Therefore, the thickness between the two flat surfaces facing each other of the spirally wound electrode body 20C becomes substantially uniform, and the thickness of the polymer support layer 23 that is gelled by the electrolytic solution can be made uniform. .

FIG. 8 is a plan view showing a third example of a preferred embodiment of the nonaqueous electrolyte secondary battery of the present invention. FIG. 9 is a schematic cross-sectional view taken along an imaginary line II-II of the nonaqueous electrolyte secondary battery shown in FIG. The II-II imaginary line is on one flat surface of the wound electrode body 20D formed so that a cross section perpendicular to the winding axis direction has a flat shape having a major axis and a minor axis with the winding axis as the center. These are lines that pass through the symmetry center point C of the shape constituting the flat surface and extend in a direction (lateral direction) orthogonal to the winding body axis direction. 8 and 9, the same members as those of the nonaqueous electrolyte secondary battery of FIGS.
As shown in FIGS. 8 and 9, the nonaqueous electrolyte secondary battery 10D of this example does not reach the II-II imaginary line passing through the symmetry center point C of the spirally wound electrode body 20D, but the II-II imaginary line. Is provided with a short positive electrode terminal 11D and a negative electrode terminal 12D that protrude in the axial direction of the wound body opposite to each other.

As shown in FIGS. 8 and 9, the wound electrode body 20 </ b> D includes a fixing tape 26 </ b> D that fixes the outermost peripheral end portion of the wound electrode body 20 </ b> D, and a cross section perpendicular to the winding axis direction is centered on the winding axis. Between the positive electrode terminal 11D and the negative electrode terminal 12D arranged to face each other on one flat surface of the wound electrode body 20D formed so as to have a flat shape having a major axis and a minor axis. It has a structure that exists on a virtual line (II-II virtual line) orthogonal to the wound body axis passing through the symmetry center point C of the wound electrode body 20D.
In the wound electrode body 20D of the present example, the positive electrode terminal 11D, the fixing tape 26D, and the negative electrode terminal 12D, which are relatively thick members, are present at positions that do not overlap each other in plan view. The thickness between two flat surfaces facing each other in 20D becomes substantially uniform, and the thickness of the polymer support layer 23 that becomes a gel by the electrolytic solution can be made uniform.

FIG. 10 is a plan view showing a second example of a preferred reference embodiment of the nonaqueous electrolyte secondary battery of the present invention. FIG. 11 is a schematic cross-sectional view taken along an imaginary line II-II of the nonaqueous electrolyte secondary battery shown in FIG. The II-II imaginary line is on one flat surface of the wound electrode body 20E formed so that a cross section perpendicular to the winding axis direction has a flat shape having a major axis and a minor axis with the winding axis as the center. These are lines that pass through the symmetry center point C of the shape constituting the flat surface and extend in a direction (lateral direction) orthogonal to the winding body axis direction. 10 and 11, the same members as those of the nonaqueous electrolyte secondary battery of FIGS.
As shown in FIGS. 10 and 11, the non-aqueous electrolyte secondary battery 10E of this example has a length that reaches the II-II imaginary line that passes through the symmetry center point C of the spirally wound electrode body 20E. A positive electrode terminal 11E and a negative electrode terminal 12E protruding in the opposite winding body axial direction are provided.

As shown in FIGS. 10 and 11, the wound electrode body 20 </ b> E is formed by winding a fixing tape 26 </ b> E that fixes the outermost peripheral end of the wound electrode body 20 </ b> E so as to have at least two opposed planes. On one plane of the rotating electrode body 20E, there is a structure between the positive electrode terminal 11E and the negative electrode terminal 12E in plan view and on the winding body axis of the wound electrode body 20E in plan view. Yes.
In the wound electrode body 20 of the present example, the positive electrode terminal 11E, the fixing tape 26E, and the negative electrode terminal 12E, which are relatively thick members, are arranged in parallel in the wound body axial direction (vertical direction) in plan view. Therefore, the thickness between the two opposing flat surfaces of the spirally wound electrode body 20E becomes substantially uniform, and the thickness of the polymer support layer 23 that is gelled by the electrolytic solution can be made uniform.

FIG. 12 is a plan view showing a fourth example of a preferred embodiment of the nonaqueous electrolyte secondary battery of the present invention. FIG. 13 is a schematic cross-sectional view taken along an imaginary line II-II of the nonaqueous electrolyte secondary battery shown in FIG. The II-II imaginary line is on one flat plane of the wound electrode body 20F formed so that a cross section perpendicular to the winding axis direction has a flat shape having a major axis and a minor axis with the winding axis as the center. These are lines that pass through the symmetry center point C of the shape constituting the flat surface and extend in a direction (lateral direction) orthogonal to the winding body axis direction. 12 and 13, the same members as those in the nonaqueous electrolyte secondary battery in FIGS.
As shown in FIG. 12, the nonaqueous electrolyte secondary battery 10F of this example includes short positive terminal 11F and negative terminal 12F that do not reach the II-II imaginary line passing through the symmetry center point C of the wound electrode body 20F. Prepare.
FIG. 14 is a rear view of the wound electrode body 20F used in the nonaqueous electrolyte secondary battery 10F shown in FIG.
As shown in FIG. 14, in this positive electrode terminal 11F, for example, an aluminum (Al) foil connected to the positive electrode 21 constituting the positive electrode terminal 11F protrudes from the wound electrode body 20F, and the terminal is provided on the protruded aluminum (Al) foil. It has an attached structure.
Similarly to the positive electrode terminal 11F, for example, a copper (Cu) foil connected to the negative electrode 22 constituting the negative electrode terminal 12F protrudes from the wound electrode body 20F, and the terminal is attached to the protruded copper (Cu) foil. Has the structure.

As shown in FIGS. 12 to 14, the wound electrode body 20 </ b> F of the present example is formed by fixing a fixing tape 26 </ b> F with the outermost peripheral end portion of the wound electrode body 20 </ b> F fixed in a cross section perpendicular to the winding axis direction. On one flat plane of the wound electrode body 20F formed so as to have a flat shape having a major axis and a minor axis with the axis as a center, a symmetrical center point C of the shape constituting the flat plane is included, and is seen in a plan view And has a structure in which the positive electrode terminal 11F and the negative electrode terminal 12F are not overlapped with each other.
In the wound electrode body 20F of this example, the fixing tape 26F is a region (rectangular shape) that spreads substantially uniformly on the one flat surface of the wound electrode body 20F around the symmetry center point C of the flat surface. Therefore, the thickness between the two flat surfaces facing each other of the spirally wound electrode body 20F is substantially uniform, and the thickness of the polymer support layer 23 that is gelled by the electrolyte is uniformized. can do.

Next, each component of the nonaqueous electrolyte secondary battery of the above example will be described in detail.
[Positive electrode]
The positive electrode 21 has, for example, a structure in which a positive electrode active material layer 21B is coated on both surfaces or one surface of a strip-shaped positive electrode current collector 21A having a pair of opposed surfaces. The positive electrode current collector 21 </ b> A has a portion exposed without being covered with the positive electrode active material layer 21 </ b> B at one end portion in the longitudinal direction, and the positive electrode terminal 11 is attached to the exposed portion.
The positive electrode current collector 21A is made of a metal foil such as an aluminum foil, a nickel foil, or a stainless steel foil.

The positive electrode active material layer 21B includes one or more positive electrode materials capable of inserting and extracting lithium as a positive electrode active material, and includes a conductive material and a binder as necessary. You may go out.
Examples of the positive electrode material capable of inserting and extracting lithium include sulfur (S), iron disulfide (FeS ₂ ), titanium disulfide (TiS ₂ ), molybdenum disulfide (MoS ₂ ), and niobium diselenide. lithium (NbSe _2), vanadium oxide _{(V 2 O} 5), chalcogenides containing no lithium, such as titanium dioxide (TiO ₂₎ and manganese dioxide (MnO ₂₎ (especially layered compound and the spinel-type compound), containing lithium Examples thereof include conductive compounds such as polyaniline, polythiophene, polyacetylene, and polypyrrole.

  Among these, lithium-containing compounds are preferable because some compounds can obtain a high voltage and a high energy density. Examples of such a lithium-containing compound include a composite oxide containing lithium and a transition metal element, and a phosphate compound containing lithium and a transition metal element. From the viewpoint of obtaining a higher voltage, cobalt is particularly preferred. (Co), nickel (Ni), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), chromium (Cr), vanadium (V), titanium (Ti) or any mixture thereof. The inclusion is preferred.

Such lithium-containing compounds are typically represented by the following general formula (1) or (2)
Li _x M ^I O ₂ (1)
Li _y M ^II PO ₄ (2)
(MI and MII in the formula indicate one or more transition metal elements, and the values of x and y vary depending on the charge / discharge state of the battery, but are generally 0.05 ≦ x ≦ 1.10, 0.05 ≦ y ≦ The compound of formula (1) generally has a layered structure, and the compound of formula (2) generally has an olivine structure.

Specific examples of the composite oxide containing lithium and a transition metal element include lithium cobalt composite oxide (Li _x CoO ₂ ), lithium nickel composite oxide (Li _x NiO ₂ ), lithium nickel cobalt composite oxide ( _Examples include Li _x Ni _1-z Co _z O ₂ (0 <z <1), lithium manganese composite oxide (LiMn ₂ O ₄ ) having a spinel structure.
Furthermore, specific examples of the phosphate compound containing lithium and a transition metal element include, for example, a lithium iron phosphate compound (LiFePO ₄ ) or a lithium iron manganese phosphate compound (LiFe _1-v Mn _v PO ₄ ( v <1)).
In these composite oxides, for the purpose of stabilizing the structure, a transition metal is partially substituted with Al, Mg or other transition metal elements or included in the crystal grain boundary, and a part of oxygen is fluorine. The thing substituted by etc. can also be mentioned. Further, at least a part of the surface of the positive electrode active material may be coated with another positive electrode active material. Moreover, you may use a positive electrode active material in mixture of multiple types.

[Negative electrode]
On the other hand, the negative electrode 22 has a structure in which, for example, a negative electrode active material layer 22B is coated on both surfaces or one surface of a strip-shaped negative electrode current collector 22A having a pair of opposed surfaces, similarly to the positive electrode 21. The negative electrode current collector 22A has an exposed portion without being provided with the negative electrode active material layer 22B at one end in the longitudinal direction, and the negative electrode terminal 12 is attached to the exposed portion.
The anode current collector 22A is made of a metal foil such as a copper foil, a nickel foil, or a stainless steel foil.

The negative electrode active material layer 22B includes one or more of a negative electrode material capable of inserting and extracting lithium ions and metallic lithium as a negative electrode active material, and a conductive material and a binder as necessary. An adhesive may be included.
Examples of the negative electrode material capable of inserting and extracting lithium include a carbon material, a metal oxide, and a polymer compound. Examples of the carbon material include non-graphitizable carbon materials, artificial graphite materials, and graphite-based materials. More specifically, pyrolytic carbons, cokes, graphites, glassy carbons, organic polymer compound firing Body, carbon fiber, activated carbon and carbon black.

  Among these, coke includes pitch coke, needle coke and petroleum coke, and the organic polymer compound fired body is carbonized by firing a polymer material such as phenol resin or furan resin at an appropriate temperature. Say things. In addition, examples of the metal oxide include iron oxide, ruthenium oxide, and molybdenum oxide, and examples of the polymer compound include polyacetylene and polypyrrole.

In addition, examples of the negative electrode material capable of inserting and extracting lithium include materials containing at least one of a metal element and a metalloid element capable of forming an alloy with lithium as a constituent element. The negative electrode material may be a single element, alloy or compound of a metal element or a metalloid element, or may have at least a part of one or more of these phases.
In the present invention, alloys include those containing one or more metal elements and one or more metalloid elements in addition to those composed of two or more metal elements. Moreover, the nonmetallic element may be included. Some of the structures include a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or a mixture of two or more of these.

Examples of such metal elements or metalloid elements include tin (Sn), lead (Pb), aluminum, indium (In), silicon (Si), zinc (Zn), antimony (Sb), bismuth (Bi), Examples include gallium (Ga), germanium (Ge), arsenic (As), silver (Ag), hafnium (Hf), zirconium (Zr), and yttrium (Y).
Among them, a group 14 metal element or metalloid element in the long-period type periodic table is preferable, and silicon or tin is particularly preferable. This is because silicon and tin have a large ability to occlude and release lithium, and a high energy density can be obtained.

Examples of the tin alloy include silicon, magnesium (Mg), nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium (Ti), germanium, bismuth, and antimony as second constituent elements other than tin. And at least one selected from the group consisting of chromium (Cr).
As an alloy of silicon, for example, as a second constituent element other than silicon, tin, magnesium, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony, and chromium can be used. The thing containing at least 1 sort (s) of them is mentioned.

  Examples of the tin compound or the silicon compound include those containing oxygen (O) or carbon (C), and may contain the second constituent element described above in addition to tin or silicon.

  The negative electrode material as described above may be an element that forms a complex oxide with lithium, such as titanium. Of course, metallic lithium may be precipitated and dissolved, and magnesium and aluminum other than lithium may be precipitated and dissolved.

[Polymer support layer]
Next, the polymer support layer 23 has ionic conductivity and can hold a non-aqueous electrolyte. In the embodiment and the reference embodiment shown in FIGS. 1 to 14, the polymer support layer 23 is in close contact with or bonded to the separator 24, but the separator 24 and the positive electrode 21, the separator 24 and the negative electrode 22, The electrode may be in close contact with or bonded to the electrode, or may not be in close contact with or bonded to the separator, and may be in close contact with or bonded to only one or both of the positive electrode 21 and the negative electrode 22.
Here, “adhesion” means that the polymer support layer 23 and the separator 24, the positive electrode 21, and the negative electrode 22 are in contact with each other to the extent that they do not move relative to each other unless a predetermined force is applied. .

  The polymer support layer 23 and the separator 24, or the polymer support layer 23 and the positive electrode or the negative electrode are in close contact or bonded to each other, so that the polymer support layer 23 holds the non-aqueous electrolyte and has a gel-like shape. In a state where the nonaqueous electrolyte layer is formed, the positive electrode 21 or the negative electrode 22 and the separator 24 are bonded via the nonaqueous electrolyte layer. The degree of adhesion is preferably such that, for example, the peel strength between the exposed portion of the positive electrode 21 and the negative electrode 22 where the active material layer is not provided and the current collector is exposed and the separator is 5 mN / mm or more. . The peel strength is measured between 6 seconds and 25 seconds after the current collector is placed on a support stand, pulled in a 180 ° direction at a speed of 10 cm / min, and the current collector is peeled off from the separator. , The average force required to peel.

Such adhesion or adhesion can reduce excess non-aqueous electrolyte that does not substantially participate in the battery reaction. In the embodiment and the reference embodiment shown in FIGS. 1 to 14, the polymer formed in a uniform thickness is used. The nonaqueous electrolyte is efficiently supplied around the electrode active material through the support layer.
Therefore, the non-aqueous electrolyte secondary battery of the embodiment and the reference embodiment shown in FIGS. 1 to 14 exhibits excellent cycle life characteristics and is used even when the amount of the non-aqueous electrolyte is smaller than the conventional amount. Since the amount of the non-aqueous electrolyte is small, the liquid leakage resistance is also excellent.

The polymer support constituting the polymer support layer is not particularly limited as long as it retains the non-aqueous electrolyte and exhibits ionic conductivity, but the copolymerization amount of acrylonitrile is 50% or more. 80% or more of acrylonitrile polymer, aromatic polyamide, acrylonitrile / butadiene copolymer, acrylic polymer comprising acrylate or methacrylate homopolymer or copolymer, acrylamide polymer, vinylidene fluoride, etc. Examples thereof include a polymer, polysulfone, and polyallylsulfone. In particular, a polymer having a copolymerization amount of 50% or more of acrylonitrile has a CN group in its side chain, so that a polymer gel electrolyte having a high dielectric constant and high ion conductivity can be produced.
In order to improve the support of non-aqueous electrolytes for these polymers and the ionic conductivity of polymer gel electrolytes from these polymers, acrylonitrile and vinyl carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, acrylamide, methacrylic Copolymerization of sulfonic acid, hydroxyalkylene glycol (meth) acrylate, alkoxyalkylene glycol (meth) acrylate, vinyl chloride, vinylidene chloride, vinyl acetate, various (meth) acrylates, preferably at a ratio of 50% or less, particularly 20% or less. It is also possible to use.

In addition, since the aromatic polyamide is a high heat-resistant polymer, it is a preferable high-molecular polymer when a polymer gel electrolyte that requires high heat resistance such as an automobile battery is required. Further, a polymer having a crosslinked structure obtained by copolymerizing butadiene or the like can also be used.
In particular, a polymer containing vinylidene fluoride as a constituent component, that is, a homopolymer, a copolymer, and a multi-component copolymer are preferable. Specifically, polyvinylidene fluoride (PVdF), polyvinylidene fluoride-hexafluoropropylene copolymer A combination (PVdF-HFP) and a polyvinylidene fluoride-hexafluoropropylene-chlorotrifluoroethylene copolymer (PVdF-HEP-CTFE) can be mentioned.

[Separator]
As the separator 24, for example, a porous film made of a polyolefin-based synthetic resin such as polypropylene (PP) or polyethylene (PE), or a porous film made of an inorganic material such as a ceramic nonwoven fabric has an ion permeability. It is large and is comprised from the insulating thin film which has predetermined | prescribed mechanical strength, It is good also as a structure which laminated | stacked these 2 or more types of porous films. In particular, those containing a polyolefin-based porous membrane are suitable because they have excellent separability between the positive electrode and the negative electrode, and can further reduce internal short circuit and open circuit voltage drop.

[Non-aqueous electrolyte]
The nonaqueous electrolytic solution may be any one containing an electrolyte salt and a nonaqueous solvent.
Here, as the electrolyte salt, any electrolyte salt may be used as long as it dissolves or disperses in a nonaqueous solvent described later, and lithium hexafluorophosphate (LiPF ₆ ) can be suitably used. Needless to say, it is not limited.
That is, lithium tetrafluoroborate (LiBF _4), lithium hexafluoroarsenate (LiAsF _6), lithium hexafluoro antimonate (LiSbF _6), lithium perchlorate (LiClO _4), four lithium aluminum chloride acid ( Inorganic lithium salts such as LiAlCl ₄ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium bis (trifluoromethanesulfone) imide (LiN (CF ₃ SO ₂ ) ₂ ), lithium bis (pentafluoromethanesulfone) imide (LiN (C ₂ F ₅ SO ₂ ) ₂ ) and lithium salts of perfluoroalkanesulfonic acid derivatives such as lithium tris (trifluoromethanesulfone) methide (LiC (CF ₃ SO ₂ ) ₃ ) can also be used. These can be used alone or in combination of two or more. It is also possible to use it.

  In addition, the content of such an electrolyte salt is preferably in the range of 0.1 mol to 0.3 mol, and more preferably in the range of 0.5 mol to 2.0 mol, with respect to 1 liter (L) of the solvent. This is because higher ion conductivity can be obtained within this range.

Examples of the non-aqueous solvent include various high dielectric constant solvents and low viscosity solvents.
As the high dielectric constant solvent, ethylene carbonate, propylene carbonate, and the like can be suitably used, but are not limited thereto, butylene carbonate, vinylene carbonate, 4-fluoro-1,3-dioxolan-2-one Cyclic carbonates such as (fluoroethylene carbonate), 4-chloro-1,3-dioxolan-2-one (chloroethylene carbonate), and trifluoromethylethylene carbonate can be used.

  Further, as a high dielectric constant solvent, instead of or in combination with a cyclic carbonate, a lactone such as γ-butyrolactone and γ-valerolactone, a lactam such as N-methylpyrrolidone, and a cyclic carbamate such as N-methyloxazolidinone A sulfone compound such as tetramethylene sulfone can also be used.

  On the other hand, diethyl carbonate can be preferably used as the low-viscosity solvent, but besides this, chain carbonates such as dimethyl carbonate, ethyl methyl carbonate and methyl propyl carbonate, methyl acetate, ethyl acetate, methyl propionate Chain carboxylic acid esters such as ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethylacetate and ethyl trimethylacetate, chain amides such as N, N-dimethylacetamide, methyl N, N-diethylcarbamate and N, Chain carbamates such as ethyl N-diethylcarbamate and ethers such as 1,2-dimethoxyethane, tetrahydrofuran, tetrahydropyran and 1,3-dioxolane can be used.

In addition, as a non-aqueous electrolyte used for the non-aqueous electrolyte secondary battery of the present invention, the high dielectric constant solvent and the low-viscosity solvent may be used alone or in combination of two or more. However, those containing 20 to 50% cyclic carbonate and 50 to 80% low viscosity solvent (low viscosity non-aqueous solvent) are preferred, and those having a boiling point of 130 ° C. or less as the low viscosity solvent are particularly preferred Is desirable.
By using such a non-aqueous electrolyte, the polymer support layer can be swelled satisfactorily with a small amount of the non-aqueous electrolyte, and both battery swelling suppression and leakage prevention and high conductivity are achieved. be able to.
If the ratio between the cyclic carbonate and the low-viscosity solvent deviates from the above range, the conductivity of the electrolytic solution is lowered, and the cycle characteristics may be lowered. Specifically, when the amount of the low-viscosity solvent is too large, the dielectric constant becomes low. On the other hand, when the amount of the low-viscosity solvent is too small, the viscosity becomes low. In either case, sufficient conductivity is obtained. Therefore, there is a possibility that good battery characteristics cannot be obtained.

Examples of the chain carbonate having a boiling point of 130 ° C. or lower include dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate.
In addition, when the cyclic carbonate derivative having a halogen atom is included as the above cyclic carbonate in the nonaqueous electrolytic solution, it is more preferable because cycle characteristics are improved. Examples of the cyclic carbonate derivative include 4-fluoro-1,3-dioxolan-2-one and 4-chloro-1,3-dioxolan-2-one. These can be used alone or in combination. As content, 0.5 to 2% is preferable. This is because if the content is small, the effect of improving the cycle characteristics is small, whereas if the content is too large, the swelling during high-temperature storage becomes large.

[Exterior body]
The exterior body 30 is configured by laminate films 30A and 30B that are exterior members in which, for example, a nylon film, an aluminum foil, and a polyethylene film are bonded together in this order. The exterior member 30 is disposed so that, for example, the polyethylene film side and the wound electrode body (wound battery element) 20 face each other, and the outer edge portions are joined to each other by fusion or an adhesive.

Note that the exterior member may be formed of 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.

  The structures that can be used as the exterior member 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 (direct) Chain low density polyethylene), PET / PE / Al / PET / LDPE (low density polyethylene), and PET / Ny / Al / LDPE / CPP.

Next, an example of a method for producing the nonaqueous electrolyte secondary battery of this example will be described.
The non-aqueous electrolyte secondary battery can be manufactured as follows.
First, the positive electrode 21 is produced. For example, when a particulate positive electrode active material is used, a positive electrode mixture is prepared by mixing a positive electrode active material and, if necessary, a conductive material and a binder, and a dispersion medium such as N-methyl-2-pyrrolidone. To produce a positive electrode mixture slurry.
Next, the positive electrode mixture slurry is applied to the positive electrode current collector 21A, dried, and compression molded to form the positive electrode active material layer 21B.

  Next, the negative electrode 22 is produced. For example, when a particulate negative electrode active material is used, a negative electrode mixture is prepared by mixing a negative electrode active material and, if necessary, a conductive material and a binder, and a dispersion medium such as N-methyl-2-pyrrolidone. To prepare a negative electrode mixture slurry. Thereafter, the negative electrode mixture slurry is applied to the negative electrode current collector 22A, dried, and compression molded to form the negative electrode active material layer 22B.

Then, the polymer support layer 23 is formed on the separator 24. As a method of forming the polymer support layer 23 on the separator 24, a method of applying a solution containing the polymer support to the surface of the separator 24 and removing the solvent, and a separately formed polymer support layer are used. A technique of closely fixing to the surface of the separator 24 is exemplified.
As a method of applying a solution containing a polymer support to the surface of the separator 24, a method of immersing the separator in a solution containing a polymer support, a method of supplying and applying by a T-die extrusion method, a spray method, a roll coater, a knife A technique of applying the solution to the surface of the substrate with a coater or the like can be mentioned.
Examples of the solvent removal treatment method for removing the solvent include a method for drying and removing, a method for extracting and removing the solvent by immersing it in a poor solvent for the polymer support, and a method for drying and removing the poor solvent, or a combination thereof. Can be used.
As a method of closely fixing the separately formed polymer support layer to the surface of the separator 24, it is possible to adhere using an adhesive, but in this case, the type of electrolyte used (acid, alkali, organic solvent, etc.) ), It is necessary to select an adhesive appropriately and to prevent clogging.
Moreover, as a method of closely attaching the polymer support layer formed on the separator, heat fusion at a temperature equal to or higher than the gel transition point can be mentioned. In particular, heat fusion while applying pressure such as hot roll compression is preferable.

  Next, the positive electrode terminal 11 is attached to the positive electrode 21 and the negative electrode terminal 12 is attached to the negative electrode 22, and then the separator 24 with the polymer support layer 23, the positive electrode 21, the same separator 24, and the negative electrode 22 are sequentially laminated and wound. Rotate and adhere the protective tape 25 to the outermost periphery to form a wound electrode body. Further, the wound electrode body is sandwiched between the exterior members 30A and 30B, and the outer peripheral edge except one side is heat-sealed to form a bag shape.

Thereafter, an electrolyte salt such as lithium hexafluorophosphate and a non-aqueous electrolyte solution containing a non-aqueous solvent such as ethylene carbonate are prepared, and injected into the wound electrode body from the opening of the exterior member 30, The opening of the exterior member 30 is heat-sealed and sealed. Thereby, the non-aqueous electrolyte is held on the polymer support layer 23, and the non-aqueous electrolyte secondary battery shown in FIGS. 1 to 14 is completed.
In this way, after the polymer support layer is formed and stored, the electrolyte is swollen to form an electrolyte. In this method, the precursor and solvent that are the raw materials for forming the polymer support are removed in advance, and the electrolyte is almost completely removed from the electrolyte. It is possible not to leave it, and the polymer support forming step can be well controlled. Therefore, the separator, the positive electrode, the negative electrode, and the polymer support layer can be adhered to each other.

  In the secondary battery described above, when charged, lithium ions are released from the positive electrode active material layer 21 </ b> B and occluded in the negative electrode active material layer 22 </ b> B through the non-aqueous electrolyte held in the polymer support layer 23. Is done. When discharging is performed, lithium ions are released from the negative electrode active material layer 22B, and are inserted in the positive electrode active material layer 21B through the polymer support layer 23 and the nonaqueous electrolytic solution.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail with reference to drawings, this invention is not limited to the following Example.

Example 1
A polymer support layer of PVdF is formed on both sides of a separator made of PE, wound together with the positive electrode and the negative electrode, and the wound outermost peripheral end is fixed with a fixing tape, as shown in FIGS. A wound electrode body 20 having the same structure as that of the first example shown was produced.
The flat positive electrode terminal 11 uses an Al foil having a thickness of 70 μm, the flat negative electrode terminal 12 uses an Ni foil having a thickness of 70 μm, and the fixing tape is made of acrylic on one side of a base material made of strip-shaped polypropylene. The thing of 65 micrometers in thickness which apply | coated the type | system | group adhesive was used.
The wound electrode body 20 was hermetically sealed under reduced pressure with an exterior member made of an aluminum laminate film molded into a bathtub shape together with the electrolytic solution to gel the PVdF polymer support layer.
Thereafter, sandwiched between two iron plates and pressurized at 3 kN at 70 ° C. for 3 minutes to bring both electrodes of the positive electrode 21 and the negative electrode 22 into contact with the separator 24, and the main surfaces of the plate-like positive electrode terminal 11 and negative electrode terminal 12 The spirally wound electrode body 20 was formed such that the portion of the spirally wound electrode body 20 facing the surface was smoothed so that the cross section perpendicular to the spiral axis had a flat shape having a major axis and a minor axis.
Thus, a nonaqueous electrolyte secondary battery having a structure similar to that shown in FIGS. 1 to 3 and having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm was produced.

In the cross-sectional view of FIG. 2, it is described that there is a gap in the central portion (winding body shaft portion) of the wound electrode body 20. Since the rotating electrode body 20 and the electrolytic solution are sealed in the exterior body 30 and then pressurized, both the positive electrode 21 and the negative electrode 22 are brought into close contact with the gelled polymer support layer 23 and the separator 24. There is no air gap inside the wound electrode body 20 of the secondary battery 10.
In the non-aqueous electrolyte secondary battery 10 of the present embodiment, among the members constituting the wound electrode body 20, the members having a large thickness, that is, the positive electrode terminal 11, the negative electrode terminal 12, and the fixing tape 26A are all flat. Since it exists in the position which does not overlap in view, the thickness between the two flat surfaces which the winding electrode body 20 opposes is substantially uniform, and the thickness of the polymer support body layer 23 gelatinized with electrolyte solution is uniform. Met.

(Example 2)
A nonaqueous electrolyte secondary having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm, in the same manner as in Example 1, except that it has the same structure as that of the second example shown in FIGS. A battery was produced.
The non-aqueous electrolyte secondary battery 10B of the present example has a fixing tape 26B for the wound electrode body 20B, a flat shape in which a cross section perpendicular to the winding axis direction has a major axis and a minor axis with the winding axis as the center. On one flat surface of the wound electrode body 20B formed to include the symmetrical center point C of the shape constituting the flat surface, and present in a position that does not overlap with the positive electrode terminal 11B and the negative electrode terminal 12B in plan view Has a structure.
In the cross-sectional view of FIG. 5, it is described that there is a gap in the center portion (winding body shaft portion) of the winding electrode body 20 </ b> B, but the winding electrode body of the nonaqueous electrolyte secondary battery 10 </ b> B. There is no void inside 20B.
The wound electrode body 20B of this example has a substantially uniform thickness between two flat surfaces facing each other, and the nonaqueous electrolyte secondary battery 10B of this example has a gelled polymer support layer 23. The thickness was uniform.

( Reference Example 3)
A nonaqueous electrolyte secondary having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm in the same manner as in Example 1 except that it has the same structure as that of the first example shown in FIGS. A battery was produced.
The nonaqueous electrolyte secondary battery 10C of the present reference example has a tape 26C for fixing the wound electrode body 20C having a flat shape in which a cross section perpendicular to the winding axis direction has a major axis and a minor axis about the winding axis. On one flat surface of the wound electrode body 20 </ b> C formed to be between the positive electrode terminal 11 </ b> C and the negative electrode terminal 12 </ b> C in a plan view and at a position parallel to the wound body axis of the wound electrode body 20 </ b> C. It has an existing structure.
In the cross-sectional view of FIG. 7, it is described that there is a gap in the center portion (winding body shaft portion) of the winding electrode body 20 </ b> C, but the winding electrode body of the nonaqueous electrolyte secondary battery 10 </ b> C. There is no void inside 20C.
Wound electrode body 20C of the present embodiment, the thickness between the two flat surfaces facing a is substantially uniform, non-aqueous electrolyte secondary battery 10C of this reference example, the polymeric support layer 23 gelled The thickness was uniform.

Example 4
A nonaqueous electrolyte secondary having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm, as in Example 1, except that it has the same structure as that of the third example shown in FIGS. A battery was produced.
The non-aqueous electrolyte secondary battery 10D of the present embodiment has a fixing tape 26D for the winding electrode body 20D, which has a flat shape in which a cross section perpendicular to the winding axis direction has a major axis and a minor axis with the winding axis as the center. Between the positive electrode terminal 11D and the negative electrode terminal 12D arranged to face each other in a plan view on one flat surface of the wound electrode body 20D formed to be a symmetrical center point of the wound electrode body 20D in a plan view It has a structure that exists on an imaginary line (II-II imaginary line) perpendicular to the winding axis passing through C.
In the cross-sectional view of FIG. 9, the winding electrode body 20 </ b> D is described so that there is a gap in the center portion (winding body shaft portion), but the winding electrode body of the nonaqueous electrolyte secondary battery 10 </ b> D. There is no void inside 20D.
The wound electrode body 20D of this example has a substantially uniform thickness between two flat surfaces facing each other, and the nonaqueous electrolyte secondary battery 10D of this example has a gelled polymer support layer 23. The thickness was uniform.

( Reference Example 5)
A nonaqueous electrolyte secondary having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm, in the same manner as in Example 1, except that it has the same structure as that of the second example shown in FIGS. A battery was produced.
The non-aqueous electrolyte secondary battery 10E of the present reference example has a tape 26E for fixing the wound electrode body 20E with a flat shape in which a cross section perpendicular to the winding axis direction has a major axis and a minor axis about the winding axis. On one flat surface of the wound electrode body 20E formed to be between the positive electrode terminal 11E and the negative electrode terminal 12E in plan view and on the wound body axis of the wound electrode body 20E in plan view It has an existing structure.
In the cross-sectional view of FIG. 11, it is described that there is a gap in the center portion (winding body shaft portion) of the winding electrode body 20 </ b> E, but the winding electrode body of the nonaqueous electrolyte secondary battery 10 </ b> E. There is no void inside 20E.
The wound electrode body 20E of this reference example has a substantially uniform thickness between two flat surfaces facing each other, and the nonaqueous electrolyte secondary battery 10E of this reference example has a gelled polymer support layer 23. The thickness was uniform.

(Example 6)
A nonaqueous electrolyte secondary battery having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm was produced in the same manner as in Example 1 having the same structure as that of the fourth example shown in FIGS. .
In the nonaqueous electrolyte secondary battery of this example, the fixing tape 26F of the wound electrode body 20 is in a position where it does not overlap with the positive electrode terminal 11F and the negative electrode terminal 12F in plan view, and the cross section orthogonal to the winding axis direction is wound. On one flat plane of the wound electrode body 20E formed so as to have a flat shape having a major axis and a minor axis with the rotation axis as the center, a position including a symmetry center point C of the shape constituting the flat plane It has an existing structure.
In the cross-sectional view of FIG. 9, the winding electrode body 20 </ b> D is described so that there is a gap in the center portion (winding body shaft portion), but the winding electrode body of the nonaqueous electrolyte secondary battery 10 </ b> D. There is no void inside 20D.
The wound electrode body 20F of this example has a substantially uniform thickness between two flat surfaces facing each other. The nonaqueous electrolyte secondary battery 10F of this example has a gelled polymer support layer 23. The thickness was uniform.

(Comparative Example 1)
A nonaqueous electrolyte secondary battery having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm was produced in the same manner as in Example 1 except that the structure shown in FIGS. 15 and 16 was used.
In the nonaqueous electrolyte secondary battery 10G of this comparative example, the fixing tape 26G of the wound electrode body 20G is overlapped with both the positive electrode terminal 11G and the negative electrode terminal 12G in a plan view, and the cross section orthogonal to the winding axis direction is wound. On one flat plane of the wound electrode body 20G formed so as to have a flat shape having a major axis and a minor axis with the rotation axis as the center, a symmetrical center point C of the shape constituting the flat plane is included, It has a structure that is unevenly distributed in one direction of the rotating body axis (longitudinal direction).
In the cross-sectional view of FIG. 16, it is described that there is a gap in the center portion (winding body shaft portion) of the winding electrode body 20G, but the winding electrode body of the nonaqueous electrolyte secondary battery 10G is described. There is no void inside 20G.
In the wound electrode body 20G of this comparative example, the part where the fixing tape 26G and the positive electrode terminal 11G overlap and the part where the fixing tape 26G and the negative electrode terminal 12G overlap each other are thicker than the other parts.
For this reason, the nonaqueous electrolyte secondary battery 10G of this comparative example has a gelation that exists in the overlapping portion when the positive electrode 21 or the negative electrode 22, the polymer support layer 23, and the separator 24 are pressurized to be in close contact with each other. The polymer support layer 23 thus evacuated to a thin portion, and the thickness of the gelled polymer support layer 23 was non-uniform.

(Comparative Example 2)
A nonaqueous electrolyte secondary battery having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm was produced in the same manner as in Example 1 except that the structure shown in FIGS. 17 and 18 was used.
The nonaqueous electrolyte secondary battery 10H of this comparative example has a structure in which the fixing tape 26H of the wound electrode body 20H is present at a position overlapping the negative electrode terminal 12 in a plan view and is unevenly distributed near one side wall. Have.
In the cross-sectional view of FIG. 18, the winding electrode body of the nonaqueous electrolyte secondary battery 10 </ b> H is described as having a gap in the center portion (winding body shaft portion) of the winding electrode body 20 </ b> H. There is no void inside 20H.
The thickness of the wound electrode body 20H of this comparative example differs between the portion where the fixing tape 26H is unevenly distributed and the portion where the fixing tape 26I is not unevenly distributed.
Therefore, the non-aqueous electrolyte secondary battery 10H of this comparative example exists in a portion overlapping the fixing tape 26H in a plan view when the polymer support layer 23 and the separator 24 are pressurized to adhere to the electrodes. The gelled polymer support layer 23 escaped to a thin portion, and the gelled polymer support layer 23 had a non-uniform thickness.

(Comparative Example 3)
A nonaqueous electrolyte secondary battery having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm was produced in the same manner as in Example 1 except that the structure shown in FIGS. 19 and 20 was used.
The nonaqueous electrolyte secondary battery 10I of this comparative example is a position where the fixing tape 20I for the wound electrode body 20I does not overlap with the positive electrode terminal 11 and the negative electrode terminal 12 in a plan view, and the wound body axial direction in the plan view. It has the structure which existed on the II-II imaginary line extended in the direction (lateral direction) orthogonal to.
In the cross-sectional view of FIG. 20, it is described that there is a gap in the center portion (winding body shaft portion) of the winding electrode body 20I. However, the winding electrode body of the nonaqueous electrolyte secondary battery 10I is described. There is no void inside 20I.
The thickness of the wound electrode body 20I of this comparative example differs between the portion where the fixing tape 26I exists and the portion where the fixing tape 26I does not exist.
Therefore, the nonaqueous electrolyte secondary battery 10I of the present comparative example exists in a portion overlapping the fixing tape 26I in a plan view when the polymer support layer 23 and the separator 24 are pressurized to adhere to the electrodes. The gelled polymer support layer 23 escaped to a thin portion, and the gelled polymer support layer 23 had a non-uniform thickness.

(Comparative Example 4)
A nonaqueous electrolyte secondary battery having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm was produced in the same manner as in Example 1 except that the structure shown in FIGS. 21 and 22 was used.
In the nonaqueous electrolyte secondary battery 10J of this comparative example, the fixing tape 26J of the wound electrode body 20J is between the positive electrode terminal 11J and the negative electrode terminal 12J in plan view, and is the same as the wound body axis (longitudinal direction). In the direction, it has a structure that exists around the circumference of the wound electrode body 20J.
In the cross-sectional view of FIG. 22, it is described that there is a gap in the central portion (winding body shaft portion) of the wound electrode body 20 </ b> J, but the wound electrode body of the nonaqueous electrolyte secondary battery 10 </ b> J. There is no void inside 20J.
The wound electrode body 10J of the present comparative example has a different thickness at a portion where the fixing tape 26J is present and a portion where the fixing tape 26I is not present.
Therefore, the nonaqueous electrolyte secondary battery 10J of the present comparative example is present at a position where the fixing tapes 26I overlap each other in plan view when the polymer support layer 23 and the separator 24 are pressurized to adhere to the electrodes. The gelled polymer support layer 23 escaped to a thin portion, and the gelled polymer support layer 23 had a non-uniform thickness.

(Comparative Example 5)
A nonaqueous electrolytic secondary battery having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm was produced in the same manner as in Example 1 except that the structure shown in FIGS.
The nonaqueous electrolyte secondary battery 10K of this comparative example is a position where the fixing tape 26K of the wound electrode body 20K does not overlap with the positive electrode terminal 11K and the negative electrode terminal 12K in a plan view, and the wound electrode body 20 faces. It has a structure that exists over one of two planes, a side surface connecting the two planes, and the other plane.
In the cross-sectional view of FIG. 24, it is described that there is a gap in the center portion (winding body shaft portion) of the winding electrode body 20K, but the winding electrode body of the non-aqueous electrolyte secondary battery 10K. There is no void inside 20K.
The thickness of the wound electrode body 20K of this comparative example differs between the portion where the fixing tape 26K is present and the portion where the fixing tape 26K is not present.
Therefore, the nonaqueous electrolyte secondary battery 10K of the present comparative example exists in a portion where the fixing tapes 26K overlap each other in a plan view when the polymer support layer 23 and the separator 24 are pressed to adhere to the electrodes. The gelled polymer support layer 23 escaped to a thin portion, and the gelled polymer support layer 23 had a non-uniform thickness.

(Comparative Example 6)
A nonaqueous electrolyte secondary battery having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm was produced in the same manner as in Example 1 except that the structure shown in FIGS. 25 and 26 was used.
The nonaqueous electrolyte secondary battery 10L of this comparative example is a position where the fixing tape 26L of the wound electrode body 20L does not overlap with the positive electrode terminal 11L and the negative electrode terminal 12L in a plan view, and faces the wound electrode body 20L. In one of the two planes, the other plane has a structure in which the fixing tape 26L is present at a position where the two tapes 26L overlap in a plan view.
In the cross-sectional view of FIG. 26, it is described that there is a gap in the center portion (winding body shaft portion) of the winding electrode body 20L, but the winding electrode body of the nonaqueous electrolyte secondary battery 10L is described. There is no void inside 20L.
The thickness of the wound electrode body 20L of this comparative example is different between a portion where the fixing tape 26L exists and a portion where the fixing tape 26L does not exist.
Therefore, the nonaqueous electrolyte secondary battery 10L of the present comparative example exists in a portion where the fixing tapes 26K overlap each other in a plan view when the polymer support layer 23 and the separator 24 are pressed to adhere to the electrodes. The gelled polymer support layer 23 escaped to a thin portion, and the gelled polymer support layer 23 had a non-uniform thickness.

(Comparative Example 7)
A separator made only of PE not having a polymer support layer of PVdF, a positive electrode, and a negative electrode are wound together, and the wound outermost end is fixed with a fixing tape to gel the polymer. A nonaqueous electrolyte secondary having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm, in the same manner as in Example 1, except that the structure shown in FIGS. 27 and 28 does not exist. A battery was produced.
In the non-aqueous electrolyte secondary battery 10M of the present embodiment, among the members constituting the wound electrode body 20M, the members having a large thickness, that is, the positive electrode terminal 11M, the negative electrode terminal 12M, and the fixing tape 26M are all flat. Since it exists in the position which does not overlap visually, the thickness between the two flat surfaces which the winding electrode body 20M opposes was substantially uniform.
However, in the non-aqueous electrolyte secondary battery 10M of this comparative example, since there is only a highly fluid electrolyte in the gap between the positive electrode 21 or the negative electrode 22 and the separator 24, the intervals between the positive electrode 21, the negative electrode 22, and the separator 24 are It became uneven.
In the cross-sectional view of FIG. 28, it is described that there is a gap in the center portion (winding body shaft portion) of the winding electrode body 20 </ b> M, but the winding electrode body of the nonaqueous electrolyte secondary battery 10 </ b> M. There is no void inside 20M.

(Comparative Example 8)
A separator made only of PE not having a polymer support layer of PVdF, a positive electrode, and a negative electrode are wound together, and the wound outermost end is fixed with a fixing tape to gel the polymer. A nonaqueous electrolyte secondary having a thickness of 3.8 mm, a width of 35.0 mm, and a height of 62.0 mm, in the same manner as in Comparative Example 1 except that the structure shown in FIGS. 29 and 30 does not exist. A battery was produced.
In the nonaqueous electrolyte secondary battery 10N of this comparative example, the tape 26N for fixing the wound electrode body 20N is overlapped with both the positive electrode terminal 11N and the negative electrode terminal 12N in plan view, and one flat surface of the wound electrode body 20N is obtained. Above, it has a structure including the symmetrical center point C of the shape constituting the flat surface and unevenly distributed in one direction of the wound body axis (vertical direction).
In the wound electrode body 20N of this comparative example, the portion where the fixing tape 26N and the positive electrode terminal 11N overlap and the portion where the fixing tape 26N and the negative electrode terminal 12N overlap each other are thicker than the other portions.
In the non-aqueous electrolyte secondary battery 10N of this comparative example, since only a highly fluid electrolyte exists in the gap between the positive electrode 21 or the negative electrode 22 and the separator 24, the intervals between the positive electrode 21, the negative electrode 22, and the separator 24 are not uniform. It became.
In the cross-sectional view of FIG. 30, the winding electrode body 20N is described as having a gap in the center (winding body shaft portion), but the winding electrode body of the nonaqueous electrolyte secondary battery 10N is described. There is no void inside 20N.

[Performance evaluation]
With respect to the battery of each example obtained as described above, the discharge capacity maintenance rate (%) after 300 cycles of charge and discharge and the maximum temperature (° C.) of the battery surface during the external short circuit test were measured as follows. . The results are shown in Table 1.

<Discharge capacity maintenance rate after charge / discharge of 300 cycles (%)>
Charging / discharging of 500 mA constant current constant voltage charging at 23 ° C. to an upper limit of 4.2 V for 2 hours and then 500 mA constant current discharging to a final voltage of 3.0 V was repeated 300 cycles.
The cycle characteristics are the capacity retention rate at the 300th cycle when the discharge capacity at the first cycle in the 500 mA discharge is 100%, that is, (discharge capacity at the 100th cycle at 500 mA discharge / discharge capacity at the first cycle at 500 mA discharge). ) × 100 (%).

<Maximum temperature of battery surface during external short circuit test (℃)>
Under an environment of 20 ° C., the battery was connected to an external resistance of 80 mΩ, and the maximum temperature on the battery surface was measured as shown in FIG. In order to measure the heat generation of the battery with high reproducibility, the temperature of the battery surface is such that the thermocouple 40 is attached to the symmetrical central point C on the plane side where the fixing tape is not provided, between the two opposing planes of the battery. Measured by fixing with In addition, when the fixing tape exists on both surfaces of the two opposing flat surfaces of the wound electrode body 20 as in Comparative Example 3 or 4, the thermocouple is adhered to the symmetrical center point C on either one of the flat surfaces. Measurement was carried out by fixing with tape.

As shown in Table 1, the nonaqueous electrolyte secondary batteries of Examples 1 , 2, 4, 6 and Reference Examples 3 and 5 are arranged at positions where the positive electrode terminal, the negative electrode terminal and the fixing tape do not overlap. Therefore, the thickness of the polymer support layer that is gelled by the electrolytic solution can be made uniform, and the cycle characteristics can be improved as compared with Comparative Examples 1-8. In the nonaqueous electrolyte secondary battery of Comparative Example 7 or 8, the discharge capacity retention rate after 300 cycles of charge / discharge was significantly reduced.
In addition, since the non-aqueous electrolyte secondary batteries of Examples 1 , 2, 4, 6 and Reference Examples 3 and 5 have a uniform thickness of the polymer support layer that is gelled by the electrolytic solution, The maximum temperature of the battery surface during the external short-circuit test is about 15 to 25 ° C. lower than the maximum temperature of the battery surface of Comparative Examples 1 to 8, and heat generation at the time of abnormality is suppressed and safety is improved. Was confirmed.

It is a disassembled perspective view which shows the 1st example of embodiment of the nonaqueous electrolyte secondary battery of this invention. FIG. 2 is a schematic cross-sectional view taken along a phantom line II-II of the spirally wound electrode body illustrated in FIG. 1 according to the first example of the embodiment of the spirally wound electrode body of the present invention. It is a top view of the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the 2nd example of embodiment of the nonaqueous electrolyte secondary battery of this invention. It is typical sectional drawing along the II-II imaginary line of the wound electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the 1st example of the reference form of the nonaqueous electrolyte secondary battery of this invention. It is typical sectional drawing along the II-II virtual line of the wound electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the 3rd example of embodiment of the nonaqueous electrolyte secondary battery of this invention. It is typical sectional drawing along the II-II imaginary line of the winding electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the 2nd example of the reference form of the nonaqueous electrolyte secondary battery of this invention. It is typical sectional drawing along the II-II virtual line of the wound electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the 4th example of embodiment of the nonaqueous electrolyte secondary battery of this invention. It is typical sectional drawing along the II-II imaginary line of the winding electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a rear view of the winding electrode body of the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the nonaqueous electrolyte secondary battery of a 1st comparative example. It is typical sectional drawing along the II-II imaginary line of the winding electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the nonaqueous electrolyte secondary battery of a 2nd comparative example. It is typical sectional drawing along the II-II virtual line of the wound electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the nonaqueous electrolyte secondary battery of a 3rd comparative example. It is typical sectional drawing along the II-II virtual line of the wound electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the nonaqueous electrolyte secondary battery of a 4th comparative example. It is typical sectional drawing along the II-II virtual line of the winding electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the nonaqueous electrolyte secondary battery of a 5th comparative example. It is typical sectional drawing along the II-II virtual line of the wound electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the nonaqueous electrolyte secondary battery of a 6th comparative example. It is typical sectional drawing along the XX imaginary line of the wound electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the nonaqueous electrolyte secondary battery of a 7th comparative example. It is typical sectional drawing along the II-II virtual line of the winding electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is a top view which shows the nonaqueous electrolyte secondary battery of the 8th comparative example. It is typical sectional drawing along the II-II virtual line of the winding electrode body used for the nonaqueous electrolyte secondary battery shown in FIG. It is explanatory drawing which shows typically the method of measuring the maximum temperature of the battery surface at the time of an external short circuit test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10B-10N ... Nonaqueous electrolyte secondary battery, 11 ... Positive electrode terminal, 12 ... Negative electrode terminal, 20, 20B-20N ... Winding electrode body (winding battery element), 21 ... Positive electrode, 21A ... Positive electrode collector , 21B ... positive electrode active material layer, 22 ... negative electrode, 22A ... negative electrode current collector, 22B ... negative electrode active material, 23 ... polymer support layer, 24 ... separator, 25a, 25b ... protective tape, 26A-26N ... for fixing Tape, 30 ... exterior body, 30A, 30B ... exterior member, 31 ... adhesion film, 40 ... thermocouple, 41 ... adhesive tape

Claims (4)

A belt-like positive electrode and a negative electrode;
A strip-shaped separator interposed between the positive electrode and the negative electrode;
A plate-like positive electrode terminal connected to the positive electrode and projecting along a winding axis direction in which the positive electrode, the negative electrode, and the separator are wound together;
A flat negative electrode terminal connected to the negative electrode and protruding along the winding axis direction;
For fixing the outermost peripheral ends of the positive electrode, the negative electrode, and the separator wound so that the cross section perpendicular to the winding axis has a flat shape having a major axis and a minor axis with the winding axis as the center The tape is present only on one flat surface of the two flat surfaces facing the main surface of the flat plate-like positive electrode terminal and / or negative electrode terminal, and the positive electrode terminal and the negative electrode terminal are wound in plan view . Opposing to the end in the direction of the rotation axis and present at a position that does not overlap the positive electrode terminal and the negative electrode terminal,
A wound electrode body in which a polymer support layer formed by supporting an electrolyte solution on a polymer is interposed between at least one of the positive electrode and the negative electrode and the separator.   The wound electrode body according to claim 1, wherein the fixing tape is present at a position including a symmetrical center point of the shape constituting the flat surface. The spirally wound electrode body according to any one of claims 1 and 2, wherein the fixing tape is present between the positive electrode terminal and the negative electrode terminal arranged to face each other in plan view. A strip-shaped separator interposed between the positive electrode and the negative electrode;
A polymer support layer that is interposed between at least one of the positive electrode and the negative electrode and the separator, and is formed by supporting an electrolytic solution on a polymer;
A plate-like positive electrode terminal connected to the positive electrode and projecting along a winding axis direction in which the positive electrode, the negative electrode, and the separator are wound together;
A flat negative electrode terminal connected to the negative electrode and protruding along the winding axis direction;
The outermost peripheral end wound by winding the positive electrode, the negative electrode, and the separator so that the cross section perpendicular to the winding axis is a flat shape having a major axis and a minor axis around the winding axis. A fixing tape that fixes at least one of the positive electrode, the negative electrode, and the separator that constitutes the portion is mounted on one flat surface of two flat surfaces that face the main surface of the flat plate positive electrode terminal and / or negative electrode terminal. A wound electrode body that is present only in a plan view and opposed to the ends in the winding axis direction of the positive electrode terminal and the negative electrode terminal in a plan view and does not overlap the positive electrode terminal and the negative electrode terminal;
A non-aqueous electrolyte,
The nonaqueous electrolyte secondary battery provided with the exterior body which accommodates the said winding electrode body and nonaqueous electrolyte.

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