JP7416738B2 - Nonaqueous electrolyte secondary battery - Google Patents

Description

The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte secondary battery that reduces the burden on a base material, a composite material layer, a separator, etc.

Non-aqueous electrolyte secondary batteries, typified by lithium-ion secondary batteries, have high energy density and high capacity, so they are used as power sources for driving electric vehicles (EVs), hybrid vehicles (HVs), etc. It is being

In general, a lithium ion secondary battery is configured such that a positive electrode plate and a negative electrode plate are laminated with a separator in between to form an electrode body, and this electrode body is housed in a battery case filled with an electrolyte. Particularly in recent years, a wound type is used in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are laminated with a separator in between, and in this state, the laminate is wound in the longitudinal direction and the compressed electrode body is housed in a battery case. Lithium-ion secondary batteries are widely used because they are efficient and compact.

FIG. 11A shows the state of the electrode body 10 in which the negative electrode plate 100, the positive electrode plate 110, and the separator 120 are laminated in the manufacturing process of the electrode body 10 of such a conventional wound type lithium ion secondary battery. 10 is a schematic diagram of a cross section in the width direction W (see FIG. 10) orthogonal to the winding direction L (see FIG. 8, the longitudinal direction of the negative electrode plate 100 and the positive electrode plate 110). As shown in FIG. 11A, when the negative electrode plate 100 and the positive electrode plate 110 are stacked, the negative electrode plate 100 and the positive electrode plate 110 are stacked with the negative electrode plate 100 and the positive electrode plate 110 being shifted in the width direction. A large number of negative electrode connection portions 103 in which the negative electrode composite material layer 102 is not provided protrude from one end in the width direction. Further, at the other end in the width direction, a large number of positive electrode connecting portions 113 in which the positive electrode composite material layer 112 is not provided protrude.

FIG. 11(b) is a schematic diagram of the electrode body 10 of such a conventional lithium ion secondary battery. In the manufacturing process, the negative electrode connecting portion 103 and the positive electrode connecting portion 113 are compressed in the thickness direction perpendicular to the winding direction L and the width direction W. FIG. 3 is a schematic diagram of a horizontal cross-section in the width direction in a state where the negative electrode current collector 13 and the positive electrode current collector 15 are welded together. As shown in FIG. 11(b), the negative electrode connection portion 103 and the positive electrode connection portion 113 are each compressed in the thickness direction and collected. The collected negative electrode connection portion 103 is welded to the negative electrode current collector 13. The positive electrode connection portion 113 is welded to the positive electrode current collector 15 . A part of the current collector welded to the connection part is provided to be exposed to the outside of the battery case, and is connected to the negative electrode external terminal 14 and the positive electrode external terminal 16 on the outside of the lithium ion secondary battery (see FIG. 7). ).

However, when the connection part and the current collector are connected in this way, the distance of the outer periphery of the wound electrode body to the position where the foil is collected is long, and the length at the connection part where the foil is collected is scattered. It ends up.

FIG. 12 is a diagram showing the configuration of the electrode body 10 shown in Patent Document 1 before being wound. In response to such problems, the following invention was disclosed in Patent Document 1. As shown in FIG. 12, the negative electrode connection portion 103 and the positive electrode connection portion 113 each have a rectangular original shape. It is cut out at the cutout portions 104 and 114 from the outer circumferential side of the winding toward the center of the winding, and the length becomes gradually shorter toward the center. FIG. 13 is a partial cross-sectional view in the width direction showing the structure of the electrode body 10 disclosed in Patent Document 1 after being wound. Since the cutout part 104 was cut out from the negative electrode connection part 103 and the cutout part 114 was cut out from the positive electrode connection part 113 in this way, when this laminate was wound, the collected negative electrode In the connecting portion 103, the positions of the tip portions are aligned.

With the configuration as in Patent Document 1, the tips of the connecting portions are aligned, and the welding area at the welded portion between the wound electrode body and the current collector can be made uniform.

Japanese Patent Application Publication No. 2014-060045

By the way, even if the tips of the connection parts are aligned, when the connection parts are collected, the connection parts on the outer periphery will be sharply bent toward the center. If it is suddenly bent, stress will be concentrated at the bent portion, which will put a strain on the base material made of metal foil, the composite material layer containing resin, the thin resin separator, etc.

The problem to be solved by the non-aqueous electrolyte secondary battery of the present invention is to reduce the burden when collecting foil on the outer periphery of the base material, composite material layer, separator, etc. when collecting foil on the connection part. be.

In order to solve the above problems, the nonaqueous electrolyte secondary battery of the present invention includes a negative electrode base material made of a strip-shaped metal foil having a substantially constant width, and a negative electrode composite material layer provided on both sides of the negative electrode base material. , a negative electrode plate having a negative electrode connection portion provided at one end in the width direction orthogonal to the longitudinal direction of the negative electrode base material and which is a portion where the negative electrode composite material layer is not provided; and a strip-shaped metal having a substantially constant width. A positive electrode base material made of foil, a positive electrode composite material layer provided on both surfaces of the positive electrode base material, and a positive electrode composite material layer provided at the other end in the width direction perpendicular to the longitudinal direction of the positive electrode base material. A laminated body including a positive electrode plate having a positive electrode connecting portion which is a portion that is not connected to the positive electrode plate, and a separator provided between the positive electrode plate and the negative electrode plate is wound in the longitudinal direction around a winding axis. At the same time, an electrode body compressed flat from a direction perpendicular to the width direction, and a negative electrode connection portion at the one end of the electrode body in the width direction are joined by welding to the negative electrode connection portion where the foil is collected. A non-aqueous electrolyte secondary battery comprising: a negative electrode current collector having a negative electrode current collector; and a positive electrode current collector having a positive electrode connecting portion at the other end joined by welding to the positive electrode connecting portion where the positive electrode connecting portion is foil-collected; At least the negative electrode plate is wound so as to be shifted toward the negative electrode connection part side as it becomes the outer periphery, or the positive electrode plate is wound so as to be shifted towards the positive electrode connection part side as it becomes the outer periphery, and the positive electrode of the positive electrode plate The composite material layer is characterized in that it faces the negative electrode composite material layer of the negative electrode plate.

In the width direction, the width Wn of the negative electrode composite material layer is formed to be longer than the width Wp of the positive electrode composite material layer by a difference ΔL, and the separator is arranged so as to cover the entire negative electrode composite material layer of the negative electrode plate, and is wound. Difference ΔPmax in the width direction between the edge at the center of the curved surface of the positive electrode composite layer on the positive terminal side of the rotated electrode body and the edge at the outermost circumference, and the positive electrode of the wound electrode body It is preferable that the sum of the widthwise position difference ΔNmax between the end at the center of the curved surface of the negative electrode composite layer on the terminal side and the end at the outermost periphery is smaller than the difference ΔL.

The positive electrode connection part is formed by winding the positive electrode composite layer on the positive terminal side of the wound electrode body so that the position of the tip of the collected foil for welding on the positive electrode current collector remains constant. It is also preferable that a widthwise position difference ΔP be set between the end of the positive electrode connecting portion at the center of the curved surface portion of the end in the direction and the end of the positive electrode connecting portion at the outermost periphery.

Further, the negative electrode connection part is formed of a negative electrode composite material layer on the negative electrode terminal side of the wound electrode body so that the position of the tip of the collected foil for welding in the negative electrode current collector is constant. It is also preferable that a widthwise position difference ΔN be set between the end of the negative electrode connecting portion at the center of the curved surface portion of the end in the winding direction and the end of the negative electrode connecting portion at the outermost circumference.

Note that at least one of the positive electrode plate and the negative electrode plate may be formed in the shape of a parallelogram with both ends thereof having a set inclination with respect to the winding direction.
It is suitably applicable when the non-aqueous electrolyte secondary battery is a lithium ion secondary battery.

According to the non-aqueous electrolyte secondary battery of the present invention, it is possible to reduce the burden of foil collecting the base material, composite material layer, separator, etc. on the outer periphery when collecting the foil at the connection portion.

(a) A schematic diagram showing the positional relationship between the negative electrode plate and the positive electrode plate in the electrode body of the present embodiment. (b) A schematic diagram showing a state in which the negative electrode connection portion and the positive electrode connection portion of the stacked electrode bodies as shown in FIG. 1(a) are collected, and the negative electrode current collector and the positive electrode current collector are welded, respectively. FIG. 2 is an enlarged view of the positive electrode connection portion side of the foil-collected electrode body shown in FIG. 1(b). (a) An expanded view of the negative electrode plate of this embodiment. (b) An expanded view of the positive electrode plate of this embodiment. (a) An expanded view of a negative electrode plate of another embodiment. (b) A developed view of a positive electrode plate of another embodiment. (a) A schematic diagram showing the positional relationship between a negative electrode plate and a positive electrode plate in an electrode body of another embodiment. (b) A schematic diagram showing a state in which the negative electrode connection portion and the positive electrode connection portion of the stacked electrode bodies as shown in FIG. 5(a) are collected, and the negative electrode current collector and the positive electrode current collector are welded, respectively. (a) A schematic diagram showing the positional relationship between a negative electrode plate and a positive electrode plate in an electrode body of another embodiment. (b) A schematic diagram showing a state in which the negative electrode connection portion and the positive electrode connection portion of the stacked electrode bodies as shown in FIG. 6(a) are collected, and the negative electrode current collector and the positive electrode current collector are welded, respectively. A perspective view of a cell battery of a lithium ion secondary battery. FIG. 3 is a schematic diagram showing the configuration of a wound electrode body. FIG. 2 is a schematic diagram showing the configuration of an electrode body of a lithium ion secondary battery. FIG. 3 is a perspective view showing the end of the wound electrode body on the negative electrode connection portion side in the width direction. (a) A schematic cross-sectional view in the width direction perpendicular to the winding direction of an electrode body in which a negative electrode plate, a positive electrode plate, and a separator are laminated in a conventional manufacturing process of an electrode body for a lithium ion secondary battery. (b) In the manufacturing process of conventional electrode bodies for lithium ion secondary batteries, the negative electrode connection part and the positive electrode connection part are compressed in the width direction perpendicular to the winding direction, and the negative electrode current collector and the positive electrode current collector are FIG. 3 is a schematic cross-sectional view of the welded state in the width direction perpendicular to the winding direction. The figure which shows the structure before the electrode body shown in patent document 1 is wound. FIG. 2 is a partial cross-sectional view in the width direction showing the structure of the electrode body disclosed in Patent Document 1 after being wound.

With reference to FIGS. 1 to 6, the non-aqueous electrolyte secondary battery of the present invention will be explained using a lithium ion secondary battery 1 as an example.
(Configuration of first embodiment)
First, the basic configuration of the lithium ion secondary battery 1 (see FIG. 7) of this embodiment will be explained. The principles of this embodiment and the conventional lithium ion secondary battery are basically the same except for the arrangement of the negative electrode plate 100 and the positive electrode plate 110. Therefore, in explaining the lithium ion secondary battery 1 of this embodiment, in order to simplify the explanation, a conventional lithium ion secondary battery as a premise will first be explained with reference to FIGS. 7 to 10.

<Basic configuration of lithium ion secondary battery 1>
FIG. 7 is a perspective view of the lithium ion secondary battery 1. As shown in FIG. 7, the lithium ion secondary battery 1 is configured as a cell battery. The lithium ion secondary battery 1 includes a rectangular parallelepiped battery case 11 having an opening on the upper side. The battery case 11 includes a lid 12 that seals the battery case 11. The electrode body 10 is housed inside the battery case 11 . A non-aqueous electrolyte 17 is injected into the battery case 11 from a liquid injection hole (not shown). The battery case 11 and the lid 12 are made of metal such as aluminum alloy. The lithium ion secondary battery 1 is configured as a sealed battery case by attaching a lid 12 to a battery case 11. The lithium ion secondary battery 1 also includes a lid 12 with a negative external terminal 14 and a positive external terminal 16, which are used for charging and discharging power.

<Electrode body 10>
FIG. 8 is a schematic diagram showing the configuration of the electrode body 10 to be wound. The electrode body 10 is formed by winding a negative electrode plate 100, a positive electrode plate 110, and a separator 120 disposed between them into a flat shape. In the negative electrode plate 100, a negative electrode composite layer 102 is formed on a negative electrode base material 101. The negative electrode connection portion 103 has no negative electrode composite material layer 102 formed on one end side in the width direction W (winding axis direction) perpendicular to the winding direction (winding direction L) and the negative electrode base material 101 is exposed. It is provided. In the positive electrode plate 110, a positive electrode composite layer 112 is formed on a positive electrode base material 111. The positive electrode composite layer 112 is not formed on the other end side in the width direction W (winding axis direction) perpendicular to the direction in which the positive electrode base material 111 is wound (winding direction L), and the positive electrode base material 111 is exposed. A positive electrode connection portion 113 is provided.

<Laminated body of electrode body 10>
FIG. 9 is a schematic diagram showing the structure of a laminate of the electrode body 10 of the lithium ion secondary battery 1. As shown in FIG. 9, the electrode body 10 of the lithium ion secondary battery 1 includes a negative electrode plate 100, a positive electrode plate 110, and a separator 120. The negative electrode plate 100 includes negative electrode composite material layers 102 on both sides of a negative electrode base material 101 . The positive electrode plate 110 includes positive electrode composite layers 112 on both sides of a positive electrode base material 111 . The negative electrode plate 100 and the positive electrode plate 110 are stacked on top of each other with a separator 120 in between to form a laminate. This laminated body is wound in the longitudinal direction around the winding axis and formed into a flat shape to constitute the electrode body 10.

Here, the end of the negative electrode composite material layer 102 on the negative electrode connection part side is referred to as "negative electrode connection part side negative electrode composite layer end 102n", and the end part of the negative electrode composite material layer 102 on the positive electrode connection part side is referred to as "positive electrode connection part side". "Negative electrode composite layer end portion 102p".

In addition, the end portion of the positive electrode composite material layer 112 on the negative electrode connection portion side is referred to as “negative electrode connection portion side positive electrode composite layer end portion 112n”, and the end portion of the positive electrode composite material layer 112 on the positive electrode connection side is referred to as “positive electrode connection portion side positive electrode composite layer end portion 112n”. "material layer end portion 112p".

The negative electrode connection portion 103 functions as a current collector that extracts electricity from the negative electrode composite material layer 102 of the negative electrode plate 100. The positive electrode connection portion 113 functions as a current collector that extracts electricity from the positive electrode composite material layer 112 of the positive electrode plate 110.

<End configuration of electrode body 10>
FIG. 10 is a perspective view showing the end of the wound electrode body 10 in the width direction W on the negative electrode connection portion side. When the electrode body 10 is wound around the winding axis, it is compressed in the thickness direction D perpendicular to the width direction W, and its cross section is shaped into a flat shape in the shape of a racing track. The flat electrode body 10 is housed in a battery case 11 as shown in FIG. 7, and a negative electrode current collector 13 is welded to the negative electrode connection portion 103. The positive electrode current collector 15 is welded to the positive electrode connection portion 113. Examples of methods for welding the connection portion and the current collector include ultrasonic welding, resistance welding, and electric welding. A negative external terminal 14 is connected to the negative current collector 13 through the lid 12, and a positive external terminal 16 is connected to the positive current collector 15.

The negative electrode plate 100 and the positive electrode plate 110 constituting the wound electrode body 10 are spirally wound from the center. When viewed in the width direction W from the negative electrode connection side, the appearance resembles that of a racing truck. The upper end and the lower end are semicircular arc shapes, and the negative electrode plate 100 and the positive electrode plate 110 form a "curved surface portion R". Further, the central portion is linear, and a “flat portion F” is formed by the negative electrode plate 100 and the positive electrode plate 110. Here, in this embodiment, a portion corresponding to the center of the semicircular arc-shaped "curved surface portion R" is referred to as a "curved surface center C."

<Negative electrode plate 100>
As shown in FIG. 9, negative electrode composite layers 102 are formed on both sides of a negative electrode base material 101 to constitute a negative electrode plate 100. In the embodiment, the negative electrode base material 101 is made of Cu foil. The negative electrode base material 101 serves as a base for the negative electrode composite material layer 102 as an aggregate, and has the function of a current collecting member that collects electricity from the negative electrode composite material layer 102. In the negative electrode plate 100, a negative electrode composite layer 102 is formed on a negative electrode base material 101 made of metal. In the first embodiment, the negative electrode active material is a material capable of intercalating and deintercalating lithium ions, and is a powdery carbon material made of graphite or the like.

The negative electrode plate 100 is produced, for example, by kneading a negative electrode active material, a solvent, and a binder, and applying the kneaded negative electrode mixture onto the negative electrode base material 101 and drying it.
<Positive electrode plate 110>
As shown in FIG. 9, a positive electrode plate 110 is configured by forming positive electrode composite material layers 112 on both sides of a positive electrode base material 111. In this embodiment, the positive electrode base material 111 is made of Al foil or Al alloy foil. The positive electrode base material 111 serves as a base for the positive electrode composite material layer 112 as an aggregate, and has the function of a current collecting member that collects electricity from the positive electrode composite material layer 112.

In the positive electrode plate 110, a positive electrode composite layer 112 is formed on the surface of a positive electrode base material 111. The positive electrode composite material layer 112 includes a positive electrode active material. The positive electrode active material is a material that can insert and release lithium, and for example, lithium cobalt oxide (LiCoO ₂ ), lithium manganate (LiMn ₂ O ₄ ), lithium nickel oxide (LiNiO ₂ ), etc. can be used. Alternatively, a material in which LiCoO ₂ , LiMn ₂ O ₄ , and LiNiO ₂ are mixed in an arbitrary ratio may be used.

Further, the positive electrode composite material layer 112 includes a conductive material. As the conductive material, for example, carbon black such as acetylene black (AB) or Ketjen black, or graphite can be used.

The positive electrode plate 110 is produced, for example, by kneading a positive electrode active material, a conductive material, a solvent, and a binder, and applying the kneaded positive electrode mixture onto the positive electrode base material 111 and drying it. be done.
<Separator 120>
The separator 120 is a nonwoven fabric made of polypropylene or the like for holding the non-aqueous electrolyte 17 between the negative electrode plate 100 and the positive electrode plate 110. As the separator 120, porous polymer membranes such as porous polyethylene membranes, porous polyolefin membranes, and porous polyvinyl chloride membranes, or lithium ion or ion conductive polymer electrolyte membranes may be used alone or in combination. You can also. When the electrode body 10 is immersed in the non-aqueous electrolyte 17, the non-aqueous electrolyte permeates from the ends of the separator 120 toward the center.

<Nonaqueous electrolyte 17>
The non-aqueous electrolyte 17 shown in FIG. 7 is a composition containing a supporting salt in a non-aqueous solvent. Here, ethylene carbonate (EC) can be used as the nonaqueous solvent. Alternatively, one or more materials selected from the group consisting of propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), etc. may be used. Supporting salts include LiPF ₆ , LiBF ₄ , LiClO _{4 , LiAsF 6 ,} LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiN(CF ₃ SO ₂ ) ₂ , LiC(CF ₃ SO ₂ ) ₃ , LiI One or more kinds of lithium compounds (lithium salts) selected from the following can be used.

<Features of this embodiment>
The lithium ion secondary battery 1 of this embodiment is characterized by the positional relationship between the negative electrode plate 100 and the positive electrode plate 110 in the electrode body 10.

<Positional relationship between negative electrode plate 100 and positive electrode plate 110>
FIG. 1A is a schematic diagram showing the positional relationship between the negative electrode plate 100 and the positive electrode plate 110 in the electrode body 10 of this embodiment. FIG. 1(a) is a cross-sectional view of the electrode body 10 along the line AA along the center C of the curved surface shown in FIG. Note that the drawings do not reflect the actual lengths of the negative electrode plate 100, the positive electrode plate 110, and the separator 120 in the thickness direction D and the width direction W. 10 is a schematic diagram for explaining the configuration of FIG. Therefore, this embodiment is not limited to the dimensions of the drawings. The same applies to other drawings.

Here, when the negative electrode plate 100 is wound, the side away from the center C of the curved surface is defined as the "outer peripheral side". Then, the negative electrode plate 100 placed at the center C of the curved surface is placed closest to the positive electrode connection part (on the right side in the figure) in the width direction W, and toward the outer periphery, the negative electrode plate 100 placed at the center C of the curved surface is placed closest to the positive electrode connection part (on the left side in the figure). It is arranged so that it shifts.

On the other hand, in the positive electrode plate 110, the positive electrode plate 110 disposed at the center C of the curved surface is disposed closest to the negative electrode connection part (left side in the figure) in the width direction W, and toward the outer circumference, the positive electrode plate 110 is placed at the positive electrode connection part side (right side). It is arranged so that it shifts.

<Negative electrode plate 100 and positive electrode plate 110 during foil collection>
In FIG. 1(b), the negative electrode connection portion 103 and the positive electrode connection portion 113 of the electrode body 10 stacked as shown in FIG. 1(a) are collected, and the negative electrode current collector 13 and the positive electrode current collector 15 are welded, respectively. FIG. In the negative electrode plate 100, the tip of the negative electrode connecting portion 103 is collected in the thickness direction D. At this time, the positive electrode plate 110 is relatively harder than the negative electrode plate 100, so the negative electrode plate 100 is bent and foil-collected at the base end 110e of the positive electrode plate 110. In this embodiment, when a plurality of negative electrode connection parts 103 are foil-collected, the position of the tips 103t of the negative electrode connection parts 103 in the width direction W is set to be constant, and the tips 103t are aligned. .

In the positive electrode plate 110, the tip of the positive electrode connecting portion 113 is collected in the thickness direction D. At this time, the positive electrode connecting portion 113 is sandwiched between the negative electrode plates 100 with the separator 120 in between. The positive electrode connecting portion 113 made of Al foil is softer than the negative electrode plate 100, and therefore, the positive electrode connecting portion 113 is bent and foil-collected together with the separator 120 at the base end 100e of the negative electrode plate 100. In this embodiment, when a plurality of positive electrode connecting parts 113 are foil-collected, the positions of the tips 113t of the positive electrode connecting parts 113 in the width direction W are set to be constant, and the tips 113t are set to be aligned. .

<Setting the first deviation amount>
FIG. 2 is an enlarged view of the positive electrode connection portion side of the collected electrode body 10 shown in FIG. 1(b). Here, the setting of the first shift amount will be explained using an enlarged view of the positive electrode connection part side.

As a premise, the “width Wn” of the negative electrode composite material layer, which is the length in the width direction W of the negative electrode composite material layer 102, is the length in the width direction W of the positive electrode composite material layer 112, as shown in FIG. 1(a). It is formed longer than the "width Wp" of a certain positive electrode composite material layer. The difference in length between the width Wn of the negative electrode composite material layer and the width Wp of the positive electrode composite material layer is defined as "difference ΔL".

Another premise is that the positive electrode composite material layer 112 is always placed at a position facing the negative electrode composite material layer 102. This is because if the positive electrode composite material layer 112 does not face the negative electrode composite material layer 102, it will be difficult to exchange lithium ions in that area. Note that the lithium ion secondary battery 1 of this embodiment has a "positive electrode regulation" in which the negative electrode capacity is larger than the positive electrode capacity, and all of the positive electrode composite material layer 112 faces the negative electrode composite material layer 102, and the lithium ion secondary battery 1 has a negative electrode capacity larger than the positive electrode capacity. If exchange is possible, the capacity of the lithium ion secondary battery 1 will not be restricted.

As shown in FIG. 2, the base end portion 100e, which is the end of the negative electrode plate 100 on the positive electrode connection portion side, is located closest to the positive electrode connection portion at the center C of the curved surface. From there, as it moves toward the outer periphery, it shifts toward the negative electrode connection part. With the position in the width direction W of the base end 100e of the negative electrode plate 100 at the center C of the curved surface as a reference, the difference in the position of the base end 100e on the outer peripheral side in the width direction W is defined as "negative electrode position difference ΔN". Then, the negative electrode position difference ΔN at the base end 100e of the outermost negative electrode plate 100 becomes the largest. This negative electrode position difference ΔN between the base end portion 100e of the outermost negative electrode plate 100 is defined as "negative electrode maximum position difference ΔNmax."

Similarly, the "positive electrode connection part side positive electrode composite layer end 112p" which is the end of the positive electrode composite material layer 112 on the positive electrode connection part side of the positive electrode plate 110 is located closest to the negative electrode connection part side at the center C of the curved surface. There is. From there, as it gets closer to the outer circumference, it shifts toward the positive electrode connection part. Based on the position in the width direction W of the positive electrode composite layer end portion 112p on the positive electrode connection portion side at the center C of the curved surface as a reference, the difference in the position of the positive electrode composite layer end portion 112p on the outer peripheral side in the width direction W is calculated. Let it be "positive electrode position difference ΔP". Then, the positive electrode position difference ΔP at the outermost positive electrode connection portion side positive electrode composite layer end portion 112p becomes the largest. This positive electrode position difference ΔP between the outermost positive electrode connection portion side positive electrode composite layer end portion 112p is defined as “positive electrode maximum position difference ΔPmax”.

As described above, firstly, as shown in FIG. The width Wp of the positive electrode composite material layer is longer than the width Wp of the positive electrode composite material layer by a difference ΔL. Second, the positive electrode composite material layer 112 is always placed at a position facing the negative electrode composite material layer 102.

Considering these preconditions, the positive electrode composite material layer 112 is allowed to be shifted by a maximum difference ΔL from the negative electrode composite material layer 102.
Here, the amount of deviation of the positive electrode composite material layer 112 from the negative electrode composite material layer 102 is the sum of the negative electrode maximum positional difference ΔNmax and the positive electrode maximum positional difference ΔPmax.

Then,
Negative electrode maximum position difference ΔNmax + positive electrode maximum position difference ΔPmax≦ΔL…(Formula 1)
The relationship satisfies the following.

Here, the negative electrode maximum position difference ΔNmax or the positive electrode maximum position difference ΔPmax is allowed to have a value of zero. That is, a configuration in which either the negative electrode plate 100 or the positive electrode plate 110 is aligned at the same position in the width direction W without deviation in the width direction W is also acceptable. The specific configuration will be explained in the third embodiment and the fourth embodiment.

By setting the first deviation amount as described above, the positive electrode composite material layer 112 always has the maximum deviation amount of the positive electrode composite material layer 112 with respect to the negative electrode composite material layer 102 within the range of the position facing the negative electrode composite material layer 102. can be set.

<Second deviation amount setting>
Regarding the deviation amount setting, the first deviation amount setting sets the maximum deviation amount, but the second deviation amount setting sets the deviation amount regarding the collected negative electrode connection part 103 and positive electrode connection part 113. It is a setting.

<Setting the amount of deviation at the positive electrode>
The positive electrode connection portion 113 shown in FIG. 2 is bent along the base end portion 100e of the negative electrode plate 100 adjacent to the curved surface center C side, and is collected. In FIG. 2, the separator 120 actually bends because it is flexible, but for ease of viewing the illustration, the illustration of the bending of the separator 120 is omitted to simplify the drawing. These positive electrode connecting portions 113 ensure that the positions of the tips 113t of the foil collecting portions 113a of the positive electrode connecting portions 113 are aligned in the width direction W, ensuring uniform conductivity, uniform mechanical stress, and preventing foreign matter from entering the tips 113t. This is preferable because it is difficult to do.

For this purpose, the length of the flat part 113c from the positive electrode composite layer end 112p on the positive electrode connection part side to the base end 100e of the negative electrode plate 100, and the bent part from the base end 100e of the negative electrode plate 100 to the foil collecting part 113a are required. It is desired that the total lengths of 113b are equal. Note that the lengths of the foil collecting portions 113a of each positive electrode connection portion 113 are equal.

<Setting the amount of deviation at the negative electrode>
The negative electrode connection portion 103 shown in FIG. 1(b) is bent along the base end portion 110e of the positive electrode plate 110 adjacent to the curved surface center C side, and is collected. Note that, as shown in FIG. 1(b), since the separator 120 is flexible, it bends together with the negative electrode plate 100. In these negative electrode connecting parts 103, the positions of the tips 103t of the foil collecting parts 103a of the negative electrode connecting parts 103 are aligned in the width direction W, which ensures uniform conductivity, uniformity of mechanical stress, and prevention of foreign matter from entering the tips 103t. This is preferable because it is difficult to do.

For this purpose, it is desirable that the length of the bent portion 103b from the base end 110e of the positive electrode plate 110 to the foil collecting portion 103a be equal. Note that the lengths of the foil collecting portions 103a of each negative electrode connection portion 103 are equal.

<Shape of negative electrode plate 100>
In order to set the amount of deviation in setting the second amount of deviation, the present embodiment includes the following configuration.

FIG. 3(a) is an expanded view of the negative electrode plate 100. The shape shown by the two-dot chain line is the shape of a conventional rectangular positive electrode plate for comparison.
As shown in FIG. 3A, when the negative electrode plate 100 is wound in the winding direction L, the lower part of the figure becomes the center of winding, and the upper part of the figure becomes the outer peripheral side. This negative electrode plate 100 is rolled up and shaped into a flat shape. In the electrode body 10, as shown in FIG. 2, the upper end is shifted from the lower end so that the position in the width direction W of the negative electrode plate 100 on the outer peripheral side is shifted by ΔNmax from the position in the width direction W of the negative electrode plate 100 at the center of the curved surface. It is located on the negative electrode connection part side in the width direction W by ΔNmax from the part.

Then, the position is specified so that the length of the bent part 103b from the base end 110e of the positive electrode plate 110 to the foil collecting part 103a is equal, and the curve is based on that position.
As a result, since the negative electrode plate 100 has such a configuration, when it is wound and shaped, the bent portion 103b from the base end 110e of the positive electrode plate 110 to the foil collecting portion 103a of the negative electrode connecting portion 103 is formed. the lengths will be equal.

<Shape of positive electrode plate 110>
FIG. 3(b) is an expanded view of the positive electrode plate 110. The shape shown by the two-dot chain line is the shape of a conventional rectangular positive electrode plate for comparison.

As shown in FIG. 3(b), when the positive electrode plate 110 is wound in the winding direction L, the lower part of the figure becomes the center of winding, and the upper part of the figure becomes the outer peripheral side. Therefore, this positive electrode plate 110 is wound and shaped into a flat shape. Then, in the electrode body 10, as shown in FIG. 2, the upper end portion is shifted from the lower end so that the position in the width direction W of the positive electrode plate 110 on the outer peripheral side is shifted by ΔPmax from the position in the width direction W of the positive electrode plate 110 at the center C of the curved surface. It is located on the positive electrode connection part side in the width direction W by ΔPmax from the part.

The length of the flat part 113c from the positive electrode composite layer end 112p on the positive electrode connection part side to the base end 100e of the negative electrode plate 100, and the length of the bent part 113b from the base end 100e of the negative electrode plate 100 to the foil collecting part 113a. Its position is specified so that the total length is equal, and the curve is based on that position.

As a result, since the positive electrode plate 110 has such a configuration, when it is wound and shaped, a flat portion 113c from the positive electrode composite layer end 112p on the positive electrode connection side to the base end 100e of the negative electrode plate 100 is formed. The total length of the bent portion 113b from the base end 100e of the negative electrode plate 100 to the foil collecting portion 113a is equal to the length of the bent portion 113b of the negative electrode plate 100.

<Lamination of negative electrode plate 100 and positive electrode plate 110>
The negative electrode plate 100 and the positive electrode plate 110 are stacked and wound as described above with a difference of ΔNmax and ΔPmax, respectively. As a result, the deviation between the negative electrode plate 100 and the positive electrode plate 110 becomes ΔNmax+ΔPmax. Since this value is adjusted to ΔNmax+ΔPmax≦ΔL, the positive electrode composite material layer 112 of the positive electrode plate 110 does not deviate from the range of the negative electrode composite material layer 102 of the negative electrode plate 100 even at the outermost periphery. As a result, the positive electrode composite material layer 112 is always in a position opposite to the negative electrode composite material layer 102.

<Method for manufacturing negative electrode plate 100 and positive electrode plate 110>
The negative electrode plate 100 and positive electrode plate 110 as described above are manufactured, for example, by the following method. The negative electrode base material 101 and the positive electrode base material 111 are created, for example, by punching a metal foil of Al, Cu, or the like having a sufficient area into a predetermined shape using a press. Alternatively, cut a metal foil such as Al or Cu with a certain width into a predetermined length, and stretch the convex part on the side opposite to the connection part using a press roll or the like. Good too.

(Effects of the first embodiment)
Since the electrode body 10 of the lithium ion secondary battery 1 of this embodiment has the above configuration, it has the following effects.

As shown in FIG. 1(b), in the positive electrode, when the position of the foil collection in the width direction W is the same, the bending angle of the positive electrode connecting portion 113 is Since the stress is relaxed, the stress applied to the metal foil of the positive electrode connection part 113 is reduced, and the load applied to the positive electrode connection part 113 can be reduced.

Further, as shown in FIG. 1(b), in the negative electrode, when compared with the conventional technology shown in FIG. 11(b), if the position of the foil collection in the width direction W is the same, is relaxed, the stress related to the metal foil of the negative electrode connection portion 103 is reduced, and the load related to the negative electrode connection portion 103 can be reduced.

As shown in FIG. 1(b), in the positive electrode, when the position of the foil collection in the width direction W is the same, the bending angle of the positive electrode connecting portion 113 is Since the stress is relaxed, the stress applied to the separator 120 can be reduced, and the load applied to the separator 120 can be reduced.

As shown in FIG. 1(b), in comparison with the prior art shown in FIG. 11(b), in the negative electrode, if the position of the foil collection in the width direction W is the same, the bending angle of the negative electrode connecting portion 103 Since the stress is relaxed, the stress applied to the separator 120 can be reduced, and the load applied to the separator 120 can be reduced.

On the negative electrode connecting portion side, the negative electrode composite layer end portion 102n on the negative electrode connecting portion side is close to the foil collecting portion 103a, so that the portion where only the metal foil with low strength is made can be shortened.
When the foil is collected, the positions of the tips 103t of the negative electrode connecting portions 103 in the width direction W are aligned, so there is no need to apply excessive tension to the metal foil on the outer peripheral side during the foil collection.

Since the positive electrode composite material layer 112 of the positive electrode plate 110 is always arranged to face the negative electrode composite material layer 102, in the case of a lithium ion secondary battery with positive electrode regulations, the capacity does not decrease.
The negative electrode plate 100 is shaped in advance by winding and shaping so that when the foil is collected, the tips 103t of the negative electrode connecting portions 103 are aligned. Therefore, the tips 103t of the negative electrode connecting portions 103 can be aligned simply by winding and shaping a predetermined negative electrode plate 100.

Similarly, the shape of the positive electrode plate 110 is shaped in advance so that when the positive electrode plate 110 is wound and collected, the tips 113t of the positive electrode connecting portions 113 are aligned. Therefore, just by winding and shaping a predetermined positive electrode plate 110, the tips 113t of the positive electrode connecting portions 113 can be aligned.

(Effects of the first embodiment)
(1-1) In the lithium ion secondary battery 1 of this embodiment, the negative electrode connecting portion 103 is wound toward the negative electrode connecting portion and the positive electrode connecting portion 113 is shifted toward the positive electrode connecting portion as the winding approaches the outer periphery. Therefore, on the negative electrode connecting portion side, the negative electrode composite layer end portion 102n on the negative electrode connecting portion side is located close to the foil collecting portion 103a, so that the portion where only the metal foil with low strength is made can be shortened. In addition, on the positive electrode connecting portion side, since the positive electrode composite layer end portion 112p on the positive electrode connecting portion side is close to the foil collecting portion 113a, the portion where only the metal foil with low strength is made can be shortened.

(1-2) In addition, in the lithium ion secondary battery 1 of this embodiment, the positive electrode connection portion 113 is shifted toward the positive electrode connection portion side and the negative electrode connection portion 103 is shifted toward the negative electrode connection portion side as the outer circumference approaches the winding. . Therefore, the bending angle of the negative electrode connecting portion 103 made of only thinner metal foil is relaxed toward the outer periphery, and the bending angle of the negative electrode plate 100 and separator 120 associated with this is relaxed. can be reduced.

(1-3) In addition, in the lithium ion secondary battery 1 of this embodiment, the negative electrode connection portion 103 is shifted toward the negative electrode connection portion side and the positive electrode connection portion 113 is shifted toward the positive electrode connection portion side as the outer circumference approaches the winding. . For this reason, the bending angle of the positive electrode connection part 113 made of only thinner metal foil is relaxed toward the outer periphery, and the bending angle of the positive electrode plate 110 and separator 120 associated with this is relaxed, and the load on the positive electrode plate 110 and separator 120 is can be reduced.

(1-4) In the lithium ion secondary battery 1 of this embodiment, the tips 103t of the negative electrode connection portions 103 of the negative electrode plate 100 are adjusted so that they coincide in the width direction W when the foils are collected. Further, the tips 113t of the positive electrode connecting portion 113 of the positive electrode plate 110 are adjusted so that they coincide in the width direction W when the foil is collected. Therefore, uniform conductivity can be obtained. Additionally, mechanical stress can be made uniform. Furthermore, there is an effect that foreign matter is less likely to get mixed into the tips 103t and 113t.

(Second embodiment)
FIG. 4(a) is an expanded view of the negative electrode plate 100 of the second embodiment. FIG. 4(b) is an expanded view of the positive electrode plate 110 of the second embodiment.

The second embodiment differs from the first embodiment in that the shapes of the negative electrode plate 100 and the positive electrode plate 110 are different. The other configurations are the same, with the only difference being that the shapes of the negative electrode plate 100 and the positive electrode plate 110 are different, and therefore the description thereof will be omitted.

In the first embodiment shown in FIG. 3A, the width Wn of the negative electrode plate 100 is constant, and the deviation of the negative electrode plate 100 is such that the positions of the tips 103t of the foil collecting portions 103a of the negative electrode plate 100 are aligned. ing. That is, when the negative electrode plate 100 is wound and shaped, the negative electrode connecting portion 103 of the negative electrode plate 100 is bent at the base end portion 110e of the positive electrode plate 110, and is connected by the bent portion 103b from here to the foil collecting portion 103a of the negative electrode connecting portion 103. Ru. At this time, the tips 103t of the negative electrode connecting portions 103 having the same length are shifted so that their positions are aligned. The shape of the negative electrode plate 100 has been specified by a curved line based on such a shift amount. On the other hand, in the negative electrode plate 100 of the second embodiment, from the lower winding center to the upper outer circumferential side shown in FIG. It is composed of straight lines so that the amount of deviation is ΔNmax. Therefore, in the second embodiment, when the negative electrode plate 100 is wound and shaped, the lengths of the bent portions 103b from the base end 110e of the positive electrode plate 110 to the foil collecting portion 103a of the negative electrode connecting portion 103 are not strictly equal. . In other words, the positions of the tips 103t of the negative electrode connecting portions 103 are not aligned.

However, even when configured in a straight line as in the second embodiment, when the negative electrode plate 100 is wound and shaped, the bent portion 103b extends from the base end 110e of the positive electrode plate 110 to the foil collecting portion 103a of the negative electrode connection portion 103. The lengths of are approximately equal. Therefore, the lithium ion secondary battery 1 of the second embodiment has the problem of reducing the burden of foil collecting the base material, composite material layer, separator, etc. on the outer periphery when collecting the foil at the connection part of the present invention. As a means for solving the problem, this embodiment has roughly the same effects as the first embodiment. On the other hand, its manufacture becomes extremely easy.

That is, in order to form the negative electrode plate 100 having a width of Wn, when the slope of the deviation is defined as "inclination θ", a strip-shaped metal foil having a width of Wn×Cos θ is simply cut in the width direction and at an inclination θ. The negative electrode plate 100 can be easily manufactured.

Although the negative electrode plate 100 has been described above, even in the positive electrode plate 110 shown in FIG. 4(b), the positions of the tips 113t of the positive electrode connecting portions 113 having the same length are not exactly aligned. However, as with the negative electrode plate 100, as a means for solving the problem of reducing the burden of foil collecting the base material, composite material layer, separator, etc. on the outer periphery when collecting the connecting portion of the present invention, This embodiment has roughly the same effects as the first embodiment. On the other hand, its manufacture becomes extremely easy. Similarly for the positive electrode plate 110, in order to form the positive electrode plate 110 with a width Wp, a strip-shaped metal foil with a width Wp x Cos θ' is aligned in the width direction, assuming that the slope of the deviation is "inclination θ'". The positive electrode plate 110 can be easily manufactured by simply cutting at the inclination θ'.

(Effects of the second embodiment)
(2-1) As described above, an effect similar to that of the first embodiment can be achieved using a simple manufacturing method.

(Third embodiment)
FIG. 5A is a schematic diagram showing the positional relationship between the negative electrode plate 100 and the positive electrode plate 110 in the electrode body 10 of the lithium ion secondary battery 1 of the third embodiment. FIG. 5B shows a state in which the negative electrode connection portion 103 and the positive electrode connection portion 113 of the electrode body 10 stacked as shown in FIG. 5A are collected and the negative electrode current collector 13 and the positive electrode current collector 15 are welded, respectively. FIG.

In the lithium ion secondary battery 1 of the first embodiment, the negative electrode plate 100 is arranged at the center C of the curved surface, and the width direction W is located closest to the positive electrode connection portion (right side in the figure), and the negative electrode plate 100 is arranged at the outer peripheral side. toward the negative electrode connection part side (left side).

On the other hand, in the positive electrode plate 110, the width direction W of the positive electrode plate 110 placed at the center C of the curved surface is placed closest to the negative electrode connection portion side (left side in the figure), and toward the outer circumference, the positive electrode plate 110 is placed at the positive electrode connection portion side (right side). It is arranged so that it shifts.

On the other hand, in the lithium ion secondary battery 1 of the third embodiment, as in the first embodiment, the negative electrode plate 100 disposed at the center C of the curved surface has the most width direction W connected to the positive electrode. side (right side in the figure), and is arranged so as to be shifted toward the outer circumferential side toward the negative electrode connection side (left side).

On the other hand, unlike the first embodiment, the positive electrode plates 110 of the third embodiment are arranged at the same position in the width direction W so that there is no deviation in the width direction W.
(Effects of the third embodiment)
(3-1) In the lithium ion secondary battery of this embodiment, the negative electrode connecting portion 103 is wound toward the negative electrode connecting portion side toward the outer periphery. Therefore, on the negative electrode connecting portion side, the negative electrode composite layer end portion 102n on the negative electrode connecting portion side is located close to the foil collecting portion 103a, so that the portion where only the metal foil with low strength is made can be shortened.

(3-2) Furthermore, in the lithium ion secondary battery of this embodiment, the negative electrode connecting portion 103 is wound toward the negative electrode connecting portion side as it approaches the outer periphery. Therefore, the bending angle of the positive electrode connecting portion 113 made of only a thinner metal foil toward the outer periphery can be relaxed, and the bending angle of the separator 120 associated with this can be relaxed, thereby reducing the load on the separator 120.

(Fourth embodiment)
FIG. 6A is a schematic diagram showing the positional relationship between the negative electrode plate 100 and the positive electrode plate 110 in the electrode body 10 of the lithium ion secondary battery 1 of the fourth embodiment. In FIG. 6(b), the negative electrode connection portion 103 and the positive electrode connection portion 113 of the electrode body 10 stacked as shown in FIG. 6(a) are collected, and the negative electrode current collector 13 and the positive electrode current collector 15 are welded, respectively. FIG.

In the lithium ion secondary battery 1 of the first embodiment, the negative electrode plate 100 is arranged at the center C of the curved surface, and the width direction W is located closest to the positive electrode connection portion (right side in the figure), and the negative electrode plate 100 is arranged at the outer peripheral side. toward the negative electrode connection part side (left side).

On the other hand, in the positive electrode plate 110, the width direction W of the positive electrode plate 110 placed at the center C of the curved surface is placed closest to the negative electrode connection portion side (left side in the figure), and toward the outer circumference, the positive electrode plate 110 is placed at the positive electrode connection portion side (right side). It is arranged so that it shifts.

On the other hand, in the lithium ion secondary battery 1 of the fourth embodiment, as in the first embodiment, the positive electrode plate 110 disposed at the center C of the curved surface has the negative electrode connection portion closest to the width direction W. side (left side in the figure), and is arranged so as to be shifted toward the outer circumferential side and toward the negative electrode connection part side (left side).

On the other hand, in the fourth embodiment, unlike the first embodiment, the negative electrode plates 100 are arranged at the same position in the width direction W so that there is no deviation in the width direction W.
(Effects of the fourth embodiment)
(4-1) In the lithium ion secondary battery 1 of the fourth embodiment, the positive electrode connection portion 113 is wound toward the positive electrode connection portion side toward the outer periphery. Therefore, the bending angle of the negative electrode connecting portion 103 made of only thinner metal foil toward the outer periphery can be relaxed, and the resulting bending angle of the separator 120 can be relaxed, thereby reducing the load on the separator 120.

(4-2) In the lithium ion secondary battery 1 of the fourth embodiment, the negative electrode connecting portion 103 is wound toward the negative electrode connecting portion side toward the outer periphery. Therefore, on the positive electrode connecting portion side, the positive electrode composite layer end portion 112p on the positive electrode connecting portion side is closer to the foil collecting portion 113a, so that the portion where only the metal foil with low strength is made can be shortened.

(Other examples)
The first to fourth embodiments can be implemented as follows.
〇The shifting method is not a method using a negative electrode plate 100 and a positive electrode plate 110 whose side edges are inclined with respect to the winding direction L as shown in FIGS. 3 and 4, but a method using a rectangular negative electrode plate 100 and a positive electrode plate. 110 itself may be used to tilt and shift the winding direction with respect to the longitudinal direction. In this case, the winding base end and the winding terminal end of the rectangular negative electrode plate 100 and positive electrode plate 110 are not in a direction perpendicular to the winding direction L.

In addition, when collecting foil, the tips 103t of the negative electrode connection portions 103 of the negative electrode plate 100 and the tips 113t of the positive electrode connection portions 113 of the positive electrode plate 110 do not necessarily need to be aligned as in the first embodiment.

In addition, the amount of deviation is sufficient as long as at least the burden caused by concentration of stress on the separator 120 is reduced. For this reason, it is not necessary that all adjacent electrode plates are evenly shifted, the amount of shift may not be uniform, or there may be some portions that are not shifted.

○ The number of windings, the number of laminated layers, the balance of thickness, width, and length, amount of deviation, angle, etc. of the electrode body 10 illustrated in the drawings are simplified or deformed for the sake of explanation, and the present invention It is not limited to.

In the embodiment, the laminate is wound and then shaped into a flat shape, but the wound type lithium ion secondary battery is not necessarily limited to one shaped into a flat shape. For example, the present invention can be suitably applied to an electrode body 10 formed in a cylindrical shape.

○The lithium ion secondary battery of this embodiment is one embodiment of the present invention, and is not limited to the embodiment, and a person skilled in the art may add, delete, or change the configuration without departing from the scope of the claims. Needless to say, it can be implemented.

1... Lithium ion secondary battery 10... Electrode body 11... Battery case 12... Lid body 13... Negative electrode current collector 14... Negative electrode external terminal 15... Positive electrode current collector 16... Positive electrode external terminal 17... Nonaqueous electrolyte 100... Negative electrode Plate 100e...Base end portion 101...Negative electrode base material 102...Negative electrode composite material layer 102p...Negative electrode composite material layer end on the positive electrode connection part side 102n...Negative electrode composite material layer end part on the negative electrode connection part side 103...Negative electrode connection part 103a... Foil collection Part 103b...Bending portion 103t...Tip 110...Positive electrode plate 110e...Base end portion 111...Positive electrode base material 112...Positive electrode composite material layer 112p...Positive electrode composite material layer end portion on positive electrode connection portion side 112n…Positive electrode composite material layer on negative electrode connection portion side End portion 113...Positive electrode connection portion 113a...Foil collection portion 113b...Bending portion 113c...Flat portion 113t...Tip 120...Separator C...Curved surface center portion R...Curved surface portion F...Flat portion W...Width direction Wn...Negative electrode composite material layer Width Wp...width of positive electrode composite layer ΔL...difference (=Wn-Wp)
ΔN...Negative electrode position difference ΔNmax...Negative electrode maximum position difference ΔP...Positive electrode position difference ΔPmax...Positive electrode maximum position difference D...Thickness direction L...Winding direction (longitudinal direction)

Claims (5)

A negative electrode base material made of a strip-shaped metal foil having a substantially constant width, a negative electrode composite material layer provided on both sides of the negative electrode base material, and a negative electrode composite material layer provided at one end in a width direction perpendicular to the longitudinal direction of the negative electrode base material. a negative electrode plate having a negative electrode connection portion which is a portion where the negative electrode composite material layer is not provided;
A positive electrode base material made of a strip-shaped metal foil having a substantially constant width, a positive electrode composite material layer provided on both sides of the positive electrode base material, and a positive electrode composite material layer provided at the other end in the width direction perpendicular to the longitudinal direction of the positive electrode base material. a positive electrode plate having a positive electrode connecting portion, which is a portion where the positive electrode composite material layer is not provided;
A laminated body including the positive electrode plate and the separator provided between the negative electrode plate is wound longitudinally around a winding axis and compressed flat from a direction perpendicular to the width direction. an electrode body,
a negative electrode current collector whose negative electrode connection portion at the one end in the width direction of the electrode body is joined by welding to the foil-collected negative electrode connection portion; A non-aqueous electrolyte secondary battery comprising: a positive electrode current collector joined to a positive electrode connection portion by welding;
At least the negative electrode plate is wound so as to shift toward the negative electrode connection portion as the outer periphery increases, or the positive electrode plate is wound toward the positive electrode connection portion side as the outer periphery increases, and
The positive electrode composite material layer of the positive electrode plate is opposed to the negative electrode composite material layer of the negative electrode plate,
In the width direction, the width Wn of the negative electrode composite layer is longer than the width Wp of the positive electrode composite layer by a difference ΔL,
The separator is arranged to cover the entire negative electrode composite layer of the negative electrode plate,
The difference ΔPmax in the position in the width direction between the end at the center of the curved surface of the positive electrode composite layer on the positive terminal side of the wound electrode body and the end at the outermost periphery, and the positive electrode of the wound electrode body. A non-aqueous electrolytic solution 2 characterized in that the sum of the widthwise position difference ΔNmax between the end at the center of the curved surface and the end at the outermost periphery of the negative electrode composite layer on the terminal side is smaller than the difference ΔL. Next battery. A negative electrode base material made of a strip-shaped metal foil having a substantially constant width, a negative electrode composite material layer provided on both sides of the negative electrode base material, and a negative electrode composite material layer provided at one end in a width direction perpendicular to the longitudinal direction of the negative electrode base material. a negative electrode plate having a negative electrode connection portion which is a portion where the negative electrode composite material layer is not provided;
A positive electrode base material made of a strip-shaped metal foil having a substantially constant width, a positive electrode composite material layer provided on both sides of the positive electrode base material, and a positive electrode composite material layer provided at the other end in the width direction perpendicular to the longitudinal direction of the positive electrode base material. a positive electrode plate having a positive electrode connecting portion, which is a portion where the positive electrode composite material layer is not provided;
A laminated body including the positive electrode plate and the separator provided between the negative electrode plate is wound longitudinally around a winding axis and compressed flat from a direction perpendicular to the width direction. an electrode body,
a negative electrode current collector whose negative electrode connection portion at the one end in the width direction of the electrode body is joined by welding to the foil-collected negative electrode connection portion; A non-aqueous electrolyte secondary battery comprising: a positive electrode current collector joined to a positive electrode connection portion by welding;
At least the negative electrode plate is wound so as to shift toward the negative electrode connection portion as the outer periphery increases, or the positive electrode plate is wound toward the positive electrode connection portion side as the outer periphery increases, and
The positive electrode composite material layer of the positive electrode plate is opposed to the negative electrode composite material layer of the negative electrode plate,
A non-aqueous electrolyte secondary battery, wherein at least one of the positive electrode plate and the negative electrode plate is formed in the shape of a parallelogram with both ends thereof having an inclination set with respect to the winding direction. The positive electrode connection part is formed by winding the positive electrode composite layer on the positive terminal side of the wound electrode body so that the position of the tip of the collected foil for welding on the positive electrode current collector remains constant. A position difference ΔP in the width direction between the end of the positive electrode connecting portion at the center of the curved surface portion of the end in the direction and the end of the positive electrode connecting portion at the outermost periphery is set. Item 2. The non-aqueous electrolyte secondary battery according to item 1 or 2. The negative electrode connection part is formed by winding the negative electrode composite material layer on the negative electrode terminal side of the wound electrode body so that the position of the tip of the collected foil for welding on the negative electrode current collector is constant. A difference ΔN between the positions in the width direction between the end of the negative electrode connecting portion at the center of the curved surface portion of the end in the direction and the end of the negative electrode connecting portion at the outermost circumference is set. The non-aqueous electrolyte secondary battery according to any one of Items 1 to 3. The nonaqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein the nonaqueous electrolyte secondary battery is a lithium ion secondary battery.

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