JP2015153691A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a configuration of a nonaqueous electrolyte secondary battery, in which short circuit between a positive electrode and a negative electrode can be suppressed.SOLUTION: A nonaqueous electrolyte secondary battery includes an electrode body 20 and a lead tab 15. The electrode body 20 is formed by winding a first electrode 21, a second electrode 22, and separators 23, 24. The first electrode 21 includes a band-shaped collector 210, and mixture layers 211, 212 formed on at least a part of one side of the collector 210. The second electrode 22 has a polarity opposite to that of the first electrode 21. The separators 23, 24 are arranged between the first electrode 21 and second electrode 22. The lead tab 15 is attached closely to one end 210a of the collector 210 in the winding direction thereof. The collector 210 is bent in the vicinity of one end 210a, so that the lead tab 15 is held in the collector 210 in the thickness direction.

Description

  The present invention relates to a non-aqueous electrolyte secondary battery.

  Conventionally, a configuration of a nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode, and an electrode body (rolled body) wound with a separator is known.

  Japanese Patent Application Laid-Open No. 2012-49089 describes a nonaqueous electrolyte secondary battery including an outer can, a wound body, a positive electrode tab, and a negative electrode tab. In this non-aqueous electrolyte secondary battery, the wound body includes a positive electrode, a negative electrode, and a separator, and the positive electrode includes a positive electrode current collector and a positive electrode active material layer. In this nonaqueous electrolyte secondary battery, an insulating tape is further attached to the first bent portion of the positive electrode current collector located on the inner peripheral end side of the positive electrode current collector.

  In the above-mentioned patent document, it is described that by applying an insulating tape, damage to the first bent portion of the positive electrode is suppressed even if the first bent portion is bent at an acute angle. Further, it is described that by attaching an insulating tape to the positive electrode tab, it is possible to suppress burrs generated by welding of the positive electrode tab from breaking through the separator.

JP 2012-49089 A

  In the non-aqueous electrolyte secondary battery described in the above patent document, it is necessary to apply an insulating tape to the electrode body. This complicates the manufacturing equipment.

  The objective of this invention is obtaining the structure of the nonaqueous electrolyte secondary battery which can suppress that a positive electrode and a negative electrode short-circuit.

  A nonaqueous electrolyte secondary battery according to an embodiment of the present invention includes an electrode body and a lead tab. The electrode body is obtained by winding a first electrode, a second electrode, and a separator. The first electrode includes a strip-shaped current collector and a mixture layer formed on a part of at least one surface of the current collector. The second electrode has a polarity opposite to that of the first electrode. The separator is disposed between the first electrode and the second electrode. The lead tab is attached in the vicinity of one end of the current collector in the winding direction. Since the current collector is bent in the vicinity of one end, the lead tab is sandwiched between the current collectors in the thickness direction.

  According to the above configuration, since the lead tab is sandwiched between the current collectors in the thickness direction, the junction between the current collector and the lead tab or the edge of the lead tab does not contact the separator. Therefore, it is possible to suppress the separator from being broken due to the junction between the current collector and the lead tab or the edge of the lead tab. Thereby, a short circuit between the first electrode and the second electrode can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the structure of the nonaqueous electrolyte secondary battery which can suppress that a positive electrode and a negative electrode short-circuit is obtained.

FIG. 1 is a perspective view showing a schematic configuration of a nonaqueous electrolyte secondary battery according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1 and is a view for explaining a schematic configuration of the electrode body. FIG. 3A is a diagram for explaining a configuration in the vicinity of the end portion of the positive electrode current collector. FIG. 3B is a diagram for explaining a configuration in the vicinity of the end portion of the positive electrode current collector. FIG. 3C is a diagram for explaining a configuration in the vicinity of the end portion of the positive electrode current collector. FIG. 4 is a schematic cross-sectional view of an electrode body provided in a nonaqueous electrolyte secondary battery according to one of the modifications of the present invention. FIG. 5A is a diagram for describing a configuration in the vicinity of the end portion of the positive electrode current collector in a modified example. FIG. 5B is a diagram for describing a configuration in the vicinity of the end portion of the positive electrode current collector in a modified example. FIG. 5C is a diagram for describing a configuration in the vicinity of the end portion of the positive electrode current collector in the modified example. FIG. 6 is a schematic cross-sectional view of an electrode body provided in a nonaqueous electrolyte secondary battery according to one of the modifications of the present invention. FIG. 7 is a schematic cross-sectional view of an electrode body provided in a nonaqueous electrolyte secondary battery according to one of the modifications of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated. In addition, in order to make the explanation easy to understand, in the drawings referred to below, the configuration is shown in a simplified or schematic manner, or some components are omitted. Further, the dimensional ratio between the constituent members shown in each drawing does not necessarily indicate an actual dimensional ratio.

[Configuration of non-aqueous electrolyte secondary battery]
FIG. 1 is a perspective view showing a schematic configuration of a nonaqueous electrolyte secondary battery 1 according to an embodiment of the present invention. The nonaqueous electrolyte secondary battery 1 includes an outer can 11, a lid plate (top cover) 12, a negative electrode terminal 13, a sealing plug 14, an electrode body 20, and an electrolyte solution (not shown).

  For convenience of explanation, the x direction, the y direction, and the z direction are determined along the outer shape of the outer can 11 as shown in FIG. The non-aqueous electrolyte secondary battery 1 is a flat battery whose dimension in the y direction is smaller than that in the x and z directions.

  The outer can 11 has a box shape with one end opened, and houses the electrode body 20 therein. The opening of the outer can 11 is blocked by the lid plate 12. The outer can 11 and the lid plate 12 are made of, for example, aluminum or an aluminum alloy.

  A negative electrode terminal 13 is disposed at the center of the lid plate 12. The negative electrode terminal 13 is formed of, for example, nickel or copper plated with nickel. The negative terminal 13 passes through the lid plate 12. The negative electrode terminal 13 is electrically connected to the negative electrode of the electrode body 20 via a negative electrode lead tab described later. The lid plate 12 and the negative electrode terminal 13 are electrically insulated by an insulating packing (not shown).

  Note that the positive electrode of the electrode body 20 is electrically connected to the lid plate 12 via a positive electrode lead tab described later. With this configuration, the lid plate 12 and the outer can 11 that is electrically connected to the lid plate 12 function as a positive electrode terminal.

  The lid plate 12 has a liquid injection port 12a for injecting an electrolytic solution. The liquid injection port 12 a passes through the lid plate 12. The liquid injection port 12a is sealed by the sealing plug 14 after the electrolytic solution is injected.

The electrolytic solution is a solution in which a lithium salt is dissolved in an organic solvent. As an organic solvent, vinylene carbonate (VC), propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), or γ- Butyrolactone and the like can be used alone or in admixture of two or more. As the lithium salt, LiPF ₆ , LiBF ₄ , LiN (CF ₃ SO ₂ ) _2, or the like can be used.

  FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1 and is a diagram for explaining a schematic configuration of the electrode body 20. In FIG. 2, only the innermost periphery of the electrode body 20 is illustrated, and illustration of the outer side of the electrode body 20 and the outer can 11 is omitted. Further, in FIG. 2, each member is illustrated with a space in order to make it easy to distinguish, but in an actual configuration, each member is arranged with almost no gap. The same applies to FIGS. 4, 6, and 7 to be described later.

  The electrode body 20 includes a strip-shaped positive electrode 21, a strip-shaped negative electrode 22, and strip-shaped separators 23 and 24. In the electrode body 20, the negative electrode 22, the separator 23, the positive electrode 21, and the separator 24 are stacked in this order, and are wound around the z direction with the negative electrode 22 inside.

  The positive electrode 21 includes a strip-shaped positive electrode current collector 210, a positive electrode mixture layer 211 formed on one surface of the positive electrode current collector 210, and a positive electrode mixture formed on the other surface of the positive electrode current collector 210. Layer 212.

  The positive electrode current collector 210 is formed of, for example, a foil such as aluminum or titanium, a plain woven wire net, an expanded metal, a lath net, or a punching metal.

  The positive electrode mixture layers 211 and 212 are formed by mixing a positive electrode active material, a conductive additive, and a binder. As the positive electrode active material, lithium manganate, lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel cobalt composite oxide, vanadium oxide, molybdenum oxide, or the like can be used. As the conductive assistant, graphite, carbon black, acetylene black, or the like can be used. As the binder, polyimide, polyamideimide, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), or the like can be used alone or in combination.

  The negative electrode 22 includes a strip-shaped negative electrode current collector 220, a negative electrode mixture layer 221 formed on one surface of the negative electrode current collector 220, and a negative electrode mixture formed on the other surface of the negative electrode current collector 220. Layer 222.

  The negative electrode current collector 220 is formed of, for example, a foil such as copper, nickel, or stainless steel, a plain woven wire net, an expanded metal, a lath net, or a punching metal.

  The negative electrode mixture layers 221 and 222 are formed by mixing a negative electrode active material and a binder. As the negative electrode active material, natural graphite, mesophase carbon, amorphous carbon, or the like can be used. As the binder, celluloses such as carboxymethyl cellulose (CMC) and hydroxypropyl cellulose (HPC), rubber binders such as styrene butadiene rubber (SBR) and acrylic rubber, PTFE, PVDF and the like can be used alone or in combination.

  Separator 23 and 24 are porous films or nonwoven fabrics, such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polyphenyl sulfide (PPS), for example.

  As shown in FIG. 2, the negative electrode mixture layer 221 is formed to face the positive electrode mixture layer 212 with the separator 23 interposed therebetween. Similarly, the negative electrode mixture layer 222 is formed to face the positive electrode mixture layer 211 with the separator 24 interposed therebetween. Since there is no positive electrode mixture layer to be opposed to the innermost periphery of the electrode body 20, the negative electrode mixture layer 222 is not formed. Therefore, in the electrode body 20, the position of the application end of the negative electrode mixture layer 221 and the position of the application end of the negative electrode mixture layer 222 are different.

  Neither of the positive electrode mixture layers 211 and 212 is formed in the vicinity of the end portion 210 a on the inner peripheral side of the positive electrode current collector 210. That is, the positive electrode current collector 210 is exposed at the inner peripheral end of the positive electrode 21. A positive electrode lead tab 15 is attached to a portion where the positive electrode current collector 210 is exposed. The positive electrode lead tab 15 is formed to extend in the z-axis direction (winding axis direction of the wound body), and is welded to the lid plate 12 (FIG. 1).

  Similarly, neither of the negative electrode mixture layers 221 and 222 is formed in the vicinity of the inner peripheral end 220a of the negative electrode current collector 220. That is, the negative electrode current collector 220 is exposed at the inner peripheral end of the negative electrode 22. A negative electrode lead tab 16 is attached to a portion where the negative electrode current collector 220 is exposed. The negative electrode lead tab 16 is formed to extend in the z-axis direction, and is welded to the negative electrode terminal 13 (FIG. 1).

  The positive electrode current collector 210 is bent toward the positive electrode lead tab 15 in the vicinity of the end portion 210a. Thus, the positive electrode lead tab 15 is sandwiched between the positive electrode current collectors 210 in the thickness direction (y direction).

[Method for Manufacturing Nonaqueous Electrolyte Secondary Battery 1]
Hereinafter, an example of the manufacturing method of the nonaqueous electrolyte secondary battery 1 will be described.

  A positive electrode active material, a conductive additive, and a binder are sufficiently mixed in pure water or an organic solvent to prepare a dispersion. The dispersion is applied to both surfaces of the positive electrode current collector 210 using a die coater, a slit coater, a dip coater or the like. At this time, the dispersion is not applied in the vicinity of the end portion 210a. After the application, the dispersion is dried, and the thickness and density are adjusted by calendaring to form the positive electrode mixture layers 211 and 212. Thereby, the positive electrode 21 is obtained.

  The positive electrode lead tab 15 is attached to the positive electrode 21. 3A to 3C are views for explaining a configuration in the vicinity of the end portion 210a of the positive electrode current collector 210. FIG.

  As shown in FIG. 3A, the positive electrode lead tab 15 is attached to the positive electrode current collector 210 with an interval equal to or larger than the width w of the positive electrode sheet tab 15 from the end portion 210 a. The positive lead tab 15 is attached by welding or a conductive adhesive, for example.

  As shown in FIG. 3B, the portion p <b> 1 from the end portion 210 a of the positive electrode current collector 210 to the end piece of the positive electrode lead tab 15 is bent so as to cover the positive electrode lead tab 15.

  Accordingly, as shown in FIGS. 2 and 3C, the positive electrode lead tab 15 is sandwiched between the positive electrode current collectors 210 in the thickness direction.

  The negative electrode active material and the binder are sufficiently mixed in pure water or an organic solvent to prepare a dispersion. The dispersion is applied to both surfaces of the negative electrode current collector 220 using a die coater, a slit coater, a dip coater, or the like. At this time, the dispersion is not applied in the vicinity of the end 220a. After the application, the dispersion is dried, and the thickness and density are adjusted by calendaring to form the negative electrode mixture layers 221 and 222. Thereby, the negative electrode 22 is obtained.

  The negative electrode lead tab 16 is attached to the portion where the negative electrode current collector 220 is exposed. The negative electrode lead tab 16 is attached by welding or a conductive adhesive, for example.

  The positive electrode 21, the negative electrode 22, and the separators 23 and 24 are wound using a winding core having a circular, elliptical, or rhombus cross-sectional shape, and then the winding core is pulled out and flattened by applying pressure in one direction. To. Alternatively, the positive electrode 21, the negative electrode 22, and the separators 23 and 24 may be wound using a winding core having a flat cross-sectional shape to form a flat electrode body. Thereby, the electrode body 20 is obtained.

  An outer can 11 and a lid plate 12 are prepared. The outer can 11 is manufactured, for example, by deep drawing a plate of aluminum or aluminum alloy. The lid plate 12 is manufactured, for example, by punching a plate of aluminum or aluminum alloy. A negative electrode terminal 13 is attached to the lid plate 12 in advance.

  The positive electrode lead tab 15 and the lid plate 12 are welded, and the negative electrode lead tab 16 and the negative electrode terminal 13 are welded. The electrode body 20 is accommodated in the outer can 11, and the lid plate 12 is fitted into the opening of the outer can 11. In this state, the inner periphery of the opening of the outer can 11 and the outer periphery of the lid plate 12 are welded.

  An electrolytic solution is injected from the injection port 12a, and preliminary charging is performed as necessary. Thereafter, the sealing plug 14 is fitted into the liquid injection port 12a, and the inner periphery of the liquid injection port 12a and the outer periphery of the sealing plug 14 are welded to seal the liquid injection port 12a. Then, the nonaqueous electrolyte secondary battery 1 is manufactured by charging to a predetermined capacity.

[Effects of non-aqueous electrolyte secondary battery 1]
When the positive electrode current collector 210 and the positive electrode lead tab 15 are welded, there may be a case where a burr is formed at the welding point. Such a burr may break the separator 23 or 24. Even if the positive electrode current collector 210 and the positive electrode lead tab 15 are joined by a method other than welding, the separator 23 or 24 may be broken by the edge of the positive electrode lead tab 15. When the separator 23 or 24 is broken, the positive electrode lead tab 15 and the negative electrode mixture layer 222 or the positive electrode lead tab 15 and the negative electrode current collector 220 may come into contact with each other. That is, the positive electrode 21 and the negative electrode 22 may be short-circuited.

  According to the present embodiment, the positive electrode lead tab 15 is sandwiched between the positive electrode current collectors 210 in the thickness direction. Therefore, the welded portion between the positive electrode current collector 210 and the positive electrode lead tab 15 or the edge of the positive electrode lead tab 15 does not contact the separators 23 and 24. Thereby, a short circuit between the positive electrode 21 and the negative electrode 22 can be suppressed.

  According to this embodiment, the positive electrode current collector 210 is bent in the vicinity of the end portion 210a, and the positive electrode current collector 210 sandwiches the positive electrode lead tab 15 in the thickness direction. According to this configuration, a member (insulating tape or the like) that only covers the positive electrode lead tab 15 is not required. Therefore, the configuration can be simplified.

  Note that burrs may also be generated at the welded portion between the negative electrode current collector 220 and the negative electrode lead tab 16. Therefore, the welded portion between the negative electrode current collector 220 and the negative electrode lead tab 16 may be covered with the negative electrode current collector 220 as in the case of the positive electrode lead tab 15. However, in the present embodiment, as shown in FIG. 2, only the negative electrode current collector 220 having the same polarity is disposed around the negative electrode lead tab 16. Therefore, the possibility that the negative electrode lead tab 16 and the positive electrode 21 are short-circuited is low. Therefore, it is not essential to cover the welded portion between the negative electrode current collector 220 and the negative electrode lead tab 16 with the negative electrode current collector 220.

  According to the present embodiment, the positive electrode lead tab 15 is attached in the vicinity of the end portion 210 a on the inner peripheral side of the positive electrode current collector 210. When the positive electrode lead tab 15 is attached in the vicinity of the end portion 210 a on the inner peripheral side of the positive electrode current collector 210, the positive electrode lead tab 15 is disposed near the center of the electrode body 20. Therefore, even if the electrode body 20 expands and contracts due to charge / discharge, the stress applied to the electrode body 20 becomes relatively symmetrical. Therefore, the distortion of the electrode body 20 can be reduced.

  The same applies to the negative electrode lead tab 16. According to this embodiment, the negative electrode lead tab 16 is attached in the vicinity of the end portion 220 a on the inner peripheral side of the negative electrode current collector 220. According to this configuration, the distortion of the electrode body 20 can be reduced.

  According to this embodiment, the electrode body 20 is wound around the z direction with the negative electrode 22 inside. In this configuration, the positive electrode lead tab 15 and the negative electrode 22 face each other with the separator interposed therebetween, regardless of the surface of the positive electrode current collector 210 where the positive electrode lead tab 15 is attached. In the present embodiment, the positive electrode lead tab 15 and the negative electrode 22 are prevented from being short-circuited by sandwiching the positive electrode lead tab 15 from both sides in the thickness direction by the positive electrode current collector 210 as described above.

[Modification of non-aqueous electrolyte secondary battery]
The nonaqueous electrolyte secondary battery 1 may include any of electrode bodies 20 </ b> A to 20 </ b> C described below instead of the electrode body 20.

  FIG. 4 is a schematic cross-sectional view of an electrode body 20 </ b> A that is one of the modifications of the electrode body 20. The electrode body 20 and the electrode body 20A are different in the configuration in the vicinity of the positive electrode lead tab 15. In the case of the electrode body 20 (FIG. 2), the portion of the positive electrode current collector 210 where the positive electrode lead tab 15 is not attached is bent. On the other hand, in the case of the electrode body 20A (FIG. 4), the portion of the positive electrode current collector 210 to which the positive electrode lead tab 15 is attached is bent.

  5A to 5C are diagrams for explaining the configuration in the vicinity of the end portion 210a of the positive electrode current collector 210 in this modification. As shown in FIG. 5A, in the electrode body 20A, the positive electrode lead tab 15 is attached closer to the end portion 210a of the positive electrode current collector 210 than in the electrode body 20 (FIG. 3A). As shown in FIG. 5B, in the electrode body 20A, the positive electrode current collector 210 has a portion p2 including both ends of the positive electrode lead tab 15 bent with the positive electrode lead tab 15 inside. As shown in FIGS. 4 and 5C, the positive electrode lead tab 15 is also sandwiched between the positive electrode current collector 210 in the thickness direction in the electrode body 20A. Therefore, the same effect as that of the electrode body 20 can be obtained by the electrode body 20A.

  FIG. 6 is a schematic cross-sectional view of an electrode body 20 </ b> B that is one of modifications of the electrode body 20. The electrode body 20 and the electrode body 20B are different in the configuration in the vicinity of the positive electrode lead tab 15.

  In the electrode body 20B, the vicinity of the end portion 210a on the inner peripheral side of the positive electrode current collector 210 is further bent inward in the winding direction from the state of the electrode body 20. That is, in the electrode body 20B, the positive electrode current collector 210 is bent twice in the vicinity of the end portion 210a.

  As a result, the positive electrode current collector 210 sandwiching the positive electrode lead tab 15 has two layers on the separator 24 side (plus side in the y direction). As a result, burrs and the like at the welded portion are difficult to reach by the separator 24. Therefore, a short circuit between the positive electrode 21 and the negative electrode 22 can be further suppressed.

  The positive electrode current collector 210 may be further bent. That is, the positive electrode current collector 210 may be bent three or more times in the vicinity of the end portion 210a.

  FIG. 7 is a schematic cross-sectional view of an electrode body 20 </ b> C that is one of modifications of the electrode body 20. The electrode body 20 and the electrode body 20C are different in the configuration in the vicinity of the positive electrode lead tab 15.

  In the electrode body 20C, the vicinity of the inner peripheral end 210a of the positive electrode current collector 210 is further bent inward in the winding direction from the state of the electrode body 20A (FIG. 4). That is, in the electrode body 20C, the positive electrode current collector 210 is bent twice in the vicinity of the end portion 210a.

  Thus, the positive electrode current collector 210 sandwiching the positive electrode lead tab 15 has two layers on the separator 24 side (minus side in the y direction). As a result, burrs and the like at the welded portion are difficult to reach by the separator 24. Therefore, a short circuit between the positive electrode 21 and the negative electrode 22 can be further suppressed.

  Also in the electrode body 20C, the positive electrode current collector 210 may be further bent. That is, the positive electrode current collector 210 may be bent three or more times in the vicinity of the end portion 210a.

[Other Embodiments]
The embodiment of the present invention has been described above. The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the invention.

  In the above-described embodiment, the case where the polarity of the outer can is the positive electrode has been described. However, the polarity of the outer can may be a negative electrode. Or it is good also as a structure which provided the positive electrode terminal insulated with the armored can separately, and the armored can was insulated from both the positive electrode and the negative electrode. Moreover, although the case where the electrode body was accommodated in the metal exterior can was demonstrated in the above-mentioned embodiment, it is good also as a structure by which the electrode body is accommodated in the laminate film etc.

  In the above-described embodiment, the case where the positive electrode lead tab 15 is sandwiched by the positive electrode current collector 210 has been described. However, instead of this, the negative electrode lead tab 16 may be sandwiched between the negative electrode current collectors 220. Alternatively, the positive electrode lead tab 15 may be sandwiched between the positive electrode current collector 210 and the negative electrode lead tab 16 may be sandwiched between the negative electrode current collector 220. That is, it is sufficient that at least one of the positive electrode lead tab 15 and the negative electrode lead tab 16 is sandwiched between the current collectors.

  In the above-described embodiment, the case where the positive electrode lead tab 15 and the negative electrode lead tab 16 are both on the inner peripheral side of the electrode body 20 has been described. However, one or both of the positive electrode lead tab 15 and the negative electrode lead tab 16 may be on the outer peripheral side of the electrode body 20.

  In the above-described embodiment, the case where the positive electrode lead tab 15 is attached to the surface closer to the separator 23 among the two surfaces of the positive electrode current collector 210 has been described. However, the positive electrode lead tab 15 may be attached to the surface close to the separator 24 among the two surfaces of the positive electrode current collector 210. In this case, the positive electrode current collector 210 may be bent in the direction opposite to that in the case of FIG. 3B (clockwise in FIG. 3).

  As illustrated by the above embodiment, the nonaqueous electrolyte secondary battery according to an embodiment of the present invention includes at least an electrode body and a lead tab. The electrode body is obtained by winding a first electrode, a second electrode, and a separator. The first electrode includes a strip-shaped current collector and a mixture layer formed on a part of at least one surface of the current collector. The second electrode has a polarity opposite to that of the first electrode. The separator is disposed between the first electrode and the second electrode. The lead tab is attached in the vicinity of one end of the current collector in the winding direction. Since the current collector is bent in the vicinity of one end, the lead tab is sandwiched between the current collectors in the thickness direction.

  According to the above configuration, since the lead tab is sandwiched between the current collectors in the thickness direction, the junction between the current collector and the lead tab or the edge of the lead tab does not contact the separator. Therefore, it is possible to suppress the separator from being broken due to the junction between the current collector and the lead tab or the edge of the lead tab. Thereby, a short circuit between the first electrode and the second electrode can be suppressed.

  The current collector is preferably bent twice or more in the vicinity of one end. According to this configuration, since the layer of the current collector disposed around the lead tab is thick, the lead tab burr and the like are more difficult to reach by the separator. Therefore, a short circuit between the first electrode and the second electrode can be further suppressed.

  The electrode body is wound with the second electrode inside, and the lead tab is preferably attached in the vicinity of the inner peripheral end of the current collector. According to this configuration, the lead tab is disposed close to the center of the electrode body. The distortion of the electrode body can be reduced.

  DESCRIPTION OF SYMBOLS 1 Nonaqueous electrolyte secondary battery, 11 Exterior can, 12 Cover plate, 13 Negative electrode terminal, 14 Sealing plug, 15 Positive electrode lead tab, 16 Negative electrode lead tab, 20, 20A-20C Electrode body, 21 Positive electrode, 210 Positive electrode current collector 211, 212 Positive electrode mixture layer, 22 Negative electrode, 220 Negative electrode current collector, 221, 222 Negative electrode mixture layer, 23, 24 Separator

Claims (3)

A first electrode including a strip-shaped current collector and a mixture layer formed on a part of at least one surface of the current collector; a second electrode having a polarity opposite to the first electrode; and the first electrode And a separator disposed between the second electrode and the second electrode,
A lead tab attached in the vicinity of one end of the current collector in the winding direction;
The non-aqueous electrolyte secondary battery, wherein the current collector is bent in the vicinity of the one end portion, whereby the lead tab is sandwiched between the current collectors in the thickness direction.   The non-aqueous electrolyte secondary battery according to claim 1, wherein the current collector is bent twice or more in the vicinity of the one end portion. The electrode body is wound with the second electrode inside,
The non-aqueous electrolyte secondary battery according to claim 1, wherein the lead tab is attached in the vicinity of an end portion on an inner peripheral side of the current collector.

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