JP2008159530A - Wound type battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wound type battery having a wound body formed by stacking a positive electrode sheet, a separator and a negative electrode sheet for winding, with reduced internal resistance. <P>SOLUTION: This wound type battery 100 is provided with the wound body 10 formed by stacking and winding the positive electrode sheet, the negative electrode sheet and the separator, a positive electrode terminal 40 and a negative electrode terminal 50. The wound body 10 is welded to the positive electrode terminal 40 on an end surface of an end 10a thereof, and a side surface of the end 10a is caulked by the positive electrode terminal 40. An end 10b of the wound body 10 and the negative terminal 50 are similarly processed. Thereby, a contact area between the wound body 10 having the positive electrode sheet and the negative electrode sheet and the positive electrode terminal 40, and that between the wound body 10 and the negative electrode terminal 50 are increased, and the positive electrode terminal 40 and the negative electrode terminal 50 are firmly joined to the wound body 10. Thereby internal resistance of the wound type battery is reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wound battery having a wound body in which a positive electrode sheet, a negative electrode sheet, and a separator are laminated and wound. The batteries referred to in this specification include secondary batteries and capacitors that can be repeatedly charged and discharged.

In the wound battery, terminals are connected to each of the positive electrode sheet and the negative electrode sheet of the wound body. The winding body is a component that generates electricity (or a component that stores electricity). Each terminal is a component for supplying electricity from the wound body to the outside. In this specification, the positive electrode sheet and the negative electrode sheet may be collectively referred to as an electrode sheet.
In the wound battery, it is preferable that the electric resistance (internal resistance of the battery) between each electrode sheet and the terminal is small. Patent Document 1 discloses a technique for reducing electrical resistance between an electrode sheet and a terminal.
The wound battery disclosed in Patent Document 1 includes an intermediate current collector that extends in the radial direction along the end face of the wound body. The intermediate current collector forms a part of the terminal. The intermediate current collector is welded to one electrode sheet at the end face of the wound body. The end surface of the wound body is formed by gathering the edges of the electrode sheet. Therefore, the edge of the electrode sheet is in contact with the intermediate current collector over almost the entire length. The contact area between the electrode sheet and the intermediate current collector (that is, the terminal) is increased by contacting the edge of the electrode sheet with the intermediate current collector over substantially the entire circumference. Thereby, reduction of the electrical resistance between an electrode sheet and an intermediate electrical power collector (namely, terminal) is aimed at.

JP-A-11-185725

  As described above, the electrical resistance between the electrode sheet and the terminal is preferably small. The present invention provides a wound battery having a further reduced electric resistance as compared with a conventional wound battery in which an electrode sheet and a terminal are brought into contact with each other at the end face of the wound body.

A wound battery according to the present invention includes a wound body obtained by laminating a positive electrode sheet, a negative electrode sheet, and a separator, and a terminal that contacts a side surface and an end surface of the wound body at one end of the wound body. . The side surface of the winding body is crimped by a terminal, and the end surface of the winding body is welded to the terminal.
In the wound battery, the electrode sheet and the terminal of either the positive electrode sheet or the negative electrode sheet are in contact with not only the edge of the electrode sheet (that is, the end surface of the wound body) but also the side surface thereof. The electrode sheet and the terminal are not only in contact with each other but are firmly connected to each other by caulking and welding. The contact area between the electrode sheet and the terminal is made larger than that of the conventional wound battery, and the electric resistance (battery internal resistance) between the wound body and the terminal can be reduced by firmly linking the both. .
The “end portion of the wound body” here means an end portion of the wound body in the axial direction. In addition, the “end portion of the wound body” refers to a portion obtained by combining an end surface that is the outermost portion in the axial direction of the wound body and a portion close to the end surface of the side surface of the wound body that is continuous with the end surface.

The wound battery of the present invention preferably further comprises the following technical features. The positive electrode sheet, the negative electrode sheet, and the separator are wound around a winding core. Either one of the positive electrode sheet and the negative electrode sheet includes a separator and an extended portion that extends longer in the axial direction of the wound body than the other electrode sheet. The extension is caulked between the terminal and the core.
When one electrode sheet has the above-described extension portion, only the extension portion overlaps in the radial direction of the winding body at one end portion of the winding body. By caulking the extension, the overlapping extension can be brought into close contact with each other. While making the extended extension part contact | adhere, the contact | adherence degree of the winding body end part and terminal which the extension part forms can be raised. The electrical resistance between the extension part of one electrode sheet and the terminal can be further reduced.
Further, by caulking the extension between the terminal and the core, the extension (that is, the wound body) can be firmly fixed between the terminal and the core. The terminal, the winding core, and the wound body can be made difficult to shift from each other.

  An active material is often applied to the surfaces of the positive electrode sheet and the negative electrode sheet. In the wound battery of the present invention, it is preferable that no active material is applied to the extension portion. The wound body can be firmly fixed by caulking the extension part to which the active material is not applied.

  In the wound battery of the present invention, it is preferable that a recess is provided on the side surface of the core, and the extension is caulked between the terminal and the recess. Thereby, the wound body can be more firmly fixed.

  In the wound battery of the present invention, it is preferable that a slit extending in the axial direction of the wound body is further provided in the extension portion of the electrode sheet. By providing the slit, it is possible to prevent the extension portion from wavy when the extension portion is caulked. As a result, the diameter of the caulked extension can be reduced. It is possible to prevent an increase in the radial size of the winding body of the terminal (that is, the diameter of the end of the wound battery).

  In a wound battery, the wound body is often immersed in an electrolytic solution. In that case, it is preferable that the wound separator is uniformly immersed in the electrolytic solution. Therefore, in the wound battery of the present invention, it is preferable that a hole is provided in at least one of the positive electrode sheet and the negative electrode sheet. By providing a hole in the electrode sheet, the electrolyte can be easily moved along the radial direction of the wound body. Through the holes provided in the electrode sheet, the electrolyte can be uniformly spread on the wound body. In other words, local drying of the electrolyte solution in the wound body can be prevented.

  In the wound battery of the present invention, it is preferable that a hole is provided on the side surface of the core. In particular, it is preferable that the core is hollow and a large number of holes are provided on the side surface of the core. The electrolyte solution can be spread uniformly in the axial direction of the wound body by the holes provided in the side surface of the winding core. Furthermore, the electrolytic solution can be stored in the hollow portion by forming the core in a hollow shape. The electrolyte stored in the hollow portion diffuses into the wound body through the holes provided in the side surface of the core. This can prevent the electrolyte from drying locally in the wound body.

  ADVANTAGE OF THE INVENTION According to this invention, the winding type battery which reduced the electrical resistance between the winding body which wound the positive electrode sheet | seat, the negative electrode sheet | seat, and the laminated body and the terminal is realizable.

First Example A wound battery according to a first example of the present invention will be described. FIG. 1 is a schematic cross-sectional view of a wound battery 100 of the first embodiment. The wound battery 100 is a nickel metal hydride battery. This battery can be repeatedly charged and discharged.
The wound battery 100 includes a wound body 10, a core 30, a positive terminal 40, a negative terminal 50, an insulating resin member 60, and a case 70. The wound body 10 is obtained by laminating a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator in this order and winding them around the core 30. The detailed structure of the wound body 10 will be described later.
A positive electrode terminal 40 is fixed to one end 10 a of the wound body 10. The end of the wound body 10 on the positive electrode terminal 40 side is referred to as a positive electrode side end 10a. The positive electrode terminal 40 is in contact with the end surface and the side surface of the wound body 10 at the positive electrode side end portion 10a. As will be described later, the end surface of the wound body 10 is welded to the positive electrode terminal 40. The side surface of the wound body 10 is caulked by the positive electrode terminal 40. A negative electrode terminal 50 is fixed to the other end 10 b of the wound body 10. The end of the wound body 10 on the negative electrode terminal 50 side is referred to as a negative electrode side end 10b. The negative electrode terminal 50 is in contact with the side surface and the end surface of the wound body 10 at the negative electrode side end portion 10b. Both the positive electrode terminal 40 and the negative electrode terminal 50 are formed of a conductive material (for example, a metal containing aluminum as a main component or a metal containing copper as a main component).
The wound body 10 is housed in a cylindrical case 70. The case 70 is formed in a cylindrical shape in which one end is closed and the other end is open. The wound body 10 is immersed in an electrolytic solution (not shown) in the case 70. The cylindrical case 70 is formed of a conductive material (for example, aluminum).
The negative electrode terminal 50 is in contact with the bottom surface of the case 70. Since the negative electrode terminal 50 and the case 70 are both formed of a conductive material, the negative electrode terminal and the outside can be electrically connected via the case 70.
A space between the positive terminal 40 and the case 70 is sealed with an insulating resin member 60. The insulating resin member 60 seals the electrolyte inside the case 70.
A part of the positive terminal 40 is exposed to the outside. Electricity generated by the wound body 10 can be supplied to the outside by the positive electrode terminal 40 and the negative electrode terminal 50. Moreover, the positive electrode terminal 40 and the negative electrode terminal 50 can supply the electricity for accumulating in the winding body 10 from the outside.

FIG. 2 shows a cross-sectional view of the wound body 10. In FIG. 2, the positive electrode terminal 40, the negative electrode terminal 50, and the core 30 are illustrated along with the wound body 10. In FIG. 2, only the left half section from the center line of the core 30 is shown.
The wound body 10 is formed by laminating a positive electrode sheet 12, a first separator 16, a negative electrode sheet 14, and a second separator 18 in this order and wound around a core 30. In FIG. 2, the positive electrode sheet 12 and the like are illustrated only in the vicinity of the outer periphery and the inner periphery of the wound body 10, and the positive electrode sheet 12 and the like are not illustrated between the outer periphery and the inner periphery. ing. In FIG. 2, “...” Indicates that the positive electrode sheet 12 and the like are not shown.
An active material 20 is applied to a part of the surface of the positive electrode sheet 12. An active material 22 is applied to a part of the surface of the negative electrode sheet 14. For the active materials 20 and 22, for example, a material such as a Ni-based oxide or a carbon-based material is used. The active material 20 and the active material 22 may be the same material or may be different materials.
As the first separator 16 and the second separator 18, for example, a polyethylene porous sheet or a sheet having a three-layer structure in which a polypropylene porous sheet is formed on both sides of a polyethylene porous sheet is used. The 1st separator 16 and the 2nd separator 18 play the role which insulates the positive electrode sheet 12 and the negative electrode sheet 14 which are located in the both sides, respectively. Hereinafter, the first separator 16 and the second separator 18 may be collectively referred to as a separator 16 or the like.

The length along the axial direction of the wound body 10 of the positive electrode sheet 12 (the vertical direction in FIG. 2, which can also be referred to as the axial direction of the core 30) is referred to as the width of the positive electrode sheet 12. Similarly, for the negative electrode sheet 14, the separator 16, and the like, the length along the axial direction of the wound body 10 is referred to as a width.
The widths of the positive electrode sheet 12 and the negative electrode sheet 14 are L1 and L2, respectively. The width of the separator 16 or the like is L4.
The positive electrode sheet 12 and the negative electrode sheet 14 are stacked while being shifted from each other by a predetermined distance in the axial direction of the wound body 10. In other words, the positive electrode sheet 12 and the negative electrode sheet 14 are laminated so as to overlap by a length L4 when viewed from the radial direction of the core 30. A separator 16 or the like is laminated between the length L4 where the positive electrode sheet 12 and the negative electrode sheet 14 overlap. In other words, the positive electrode sheet 12 has a portion that extends longer in the axial direction of the wound body 10 than the negative electrode sheet 14, the first separator 16, and the second separator 18 on the positive electrode side end 10 a side of the wound body 10. is doing. This portion is referred to as an extension portion 12b of the positive electrode sheet 12. The portion other than the extended portion of the positive electrode sheet 12 is referred to as a main portion 12 a of the positive electrode sheet 12. In FIG. 2, in the positive electrode sheet 12, a portion corresponding to the width L4 is the main portion 12a, and a portion corresponding to the width L3 is the extension portion 12b.
Similarly, the negative electrode sheet 14 has a portion that extends longer in the axial direction of the wound body 10 than the positive electrode sheet 12, the separator 16, and the like on the negative electrode side end 10 b side of the wound body 10. This portion is referred to as an extension 14b of the negative electrode sheet 14. The portion other than the extended portion of the negative electrode sheet 14 is referred to as a main portion 14 a of the negative electrode sheet 14. In FIG. 2, in the negative electrode sheet 14, the portion corresponding to the width L4 is the main portion 14a, and the portion corresponding to the width L5 is the extension portion 14b.
As shown in FIG. 2, the active material 20 is applied to the surface of the main portion 12 a of the positive electrode sheet 12. The active material is not applied to the extension 12b of the positive electrode sheet 12. An active material 22 is applied to the surface of the main portion 14 a of the negative electrode sheet 14. The active material is not applied to the extension portion 14b of the negative electrode sheet 14.

As shown in FIG. 2, the extended portion 12 b of the wound positive electrode sheet 12 is fixed between the core 30 and the positive terminal 40. More specifically, the extension portion 12 b is fixed between the outer peripheral portion of the positive electrode terminal 40 and the core 30. The extended portion 12b of the wound positive electrode sheet 12 is caulked in the radial direction of the core 30 by a positive electrode terminal 40 and fixed.
At the positive electrode side end portion 10 a of the wound body 10, only the extension portion 12 b of the positive electrode sheet 12 is wound. Accordingly, at the positive electrode side end portion 10 a of the wound body 10, only the laminated extension portion 12 b is caulked between the outer peripheral portion of the positive electrode terminal 40 and the core 30.
Further, as described above, the positive electrode terminal 40 is in contact with the end face of the positive electrode side end portion 10 a of the wound body 10. The end surface of the positive electrode side end portion 10 a of the wound body 10 is a surface formed by winding the edge portion 12 c on the positive electrode terminal 40 side of the positive electrode sheet 12. That is, the positive electrode terminal 40 is in contact with the edge portion 12 c of the positive electrode sheet 12 at the end surface of the wound body 10, and is in surface contact with the surface of the extension portion 12 b of the positive electrode sheet 12 at the side surface of the end portion 10 a of the wound body 10. .
The connection state of the positive electrode terminal 40 and the wound body 10 can be expressed as follows. At the positive electrode side end portion 10a of the wound body 10, only the positive electrode sheet 12 is wound (more specifically, only the extension portion 12b of the positive electrode sheet 12 is wound). The positive electrode terminal 40 is in contact with the positive electrode sheet 12 at the end surface and the side surface of the positive electrode side end portion 10 a of the wound body 10. With this structure, the contact area between the positive electrode terminal 40 and the positive electrode sheet 12 is increased. As a result, the resistance between the positive electrode sheet 12 and the positive electrode terminal 40 of the wound body 10 (part of the internal resistance of the wound battery 100) has been successfully reduced. Moreover, by winding the winding body 10 between the winding core 30 and the positive electrode terminal 40, the winding body 10, the winding core 30, and the positive electrode terminal 40 can be firmly fixed to each other.
The edge 12c of the positive electrode sheet 12 and the positive electrode terminal 40 are welded. Further, the caulking is stopped by a method called energizing caulking.
The edge 12c of the positive electrode sheet 12 and the positive electrode terminal 40 are welded, and the side surface of the positive electrode sheet 12 (side surface of the extension 12b) is caulked by the positive electrode terminal 40, whereby the positive electrode sheet 12 and the positive electrode terminal The electrical resistance between 40 is reduced.
Moreover, since the active material is not apply | coated to the extension part 12b, the surfaces of the extension part 12b can be made to adhere | attach and crimp. This also reduces the electrical resistance between the positive electrode sheet 12 and the positive electrode terminal 40. Furthermore, the extension portion 12b can be caulked and stopped more firmly than when the extension portion coated with the active material is caulked.

At the negative electrode side end portion 10b of the wound body 10, the wound body 10 and the negative electrode terminal 50 are fixed in the same structure as the positive electrode side end portion 10a. The connection structure of the negative electrode side end portion 10b of the wound body 10 and the negative electrode terminal 50 can be expressed as follows.
At the negative electrode side end portion 10b of the wound body 10, only the negative electrode sheet 14 is wound (more specifically, only the extension portion 14b of the negative electrode sheet 14 is wound). The negative electrode terminal 50 is in contact with the negative electrode sheet 14 at the end surface and the side surface of the negative electrode side end portion 10 b of the wound body 10. The end surface of the negative electrode side end portion 10b of the wound body 10 is a surface formed by winding the edge portion 14c of the negative electrode sheet 14 on the negative electrode terminal 50 side. With this structure, in the wound battery 100, the contact area between the negative electrode terminal 50 and the negative electrode sheet 14 is increased. As a result, the resistance between the negative electrode sheet 14 of the wound body 10 and the negative electrode terminal 50 (part of the internal resistance of the wound battery 100) has been successfully reduced.
Furthermore, the winding body 10 can be more firmly fixed to the core 30 by caulking the winding body 10 to the core 30 with the positive electrode terminal 40 and the negative electrode terminal 50.

Second Example Next, a wound battery according to a second example of the present invention will be described. The wound type battery of this example is different from the wound type battery of the first example in that the positive electrode sheet, the negative electrode sheet, and the wound core have holes. Other components are the same as those of the wound battery 100 of the first embodiment. Therefore, the schematic cross section of the wound battery of the present example is the same as FIG.
In FIG. 3, sectional drawing of the winding body 110 and the winding core 130 of the winding type battery of a present Example is shown. In FIG. 3, reference numerals are omitted for some of the same components as the components shown in FIG. 2. Parts whose reference numerals are omitted are parts having the same structure as the corresponding parts in FIG.
In the wound battery of this example, the uncoated region of the active material 20 is formed near both ends of the main portion 112a of the positive electrode sheet 112. This uncoated region is a portion corresponding to the width L6 and the width L7 in the main portion 112a having the width L4. A plurality of holes 113 are provided in the uncoated area of the main portion 112a. The plurality of holes 113 are provided at substantially equal intervals along the winding direction. The plurality of holes 113 are provided at positions overlapping the separator 16 and the like when viewed from the radial direction of the wound body 110.
An uncoated region of the active material 22 is formed near both ends of the main portion 114 a of the negative electrode sheet 114. This uncoated region is a portion corresponding to the width L6 and the width L7 in the main portion 114a having the width L4. A plurality of holes 115 are provided in the uncoated area of the main portion 114a. The plurality of holes 115 are provided at substantially equal intervals along the winding direction. The plurality of holes 115 are provided at positions overlapping the separator 16 and the like when viewed from the radial direction of the wound body 110.
Further, the core 130 has a hollow cylindrical shape, and a plurality of holes 131 are provided on a side surface thereof.

The wound body 110 is immersed in the electrolytic solution inside the case. That is, the active materials 20 and 22 and the separator 16 are impregnated with the electrolytic solution. When the electrolyte solution such as the active materials 20 and 22 and the separator 16 is dried, the performance of the battery is deteriorated. When a wound battery is used, the wound battery generates heat. There may be a local variation in the amount of heat generated inside the wound battery. For this reason, the density of the electrolyte solution becomes coarse and dense inside the battery due to evaporation of the electrolyte solution and the like. An area where the electrolyte is locally dried may be generated inside the wound body 110. If the electrolytic solution produces a dry region, the performance of the battery is degraded. By providing the holes 113, 115, and 131, the electrolyte can easily move in the radial direction of the wound body 110, and the electrolyte can easily spread uniformly inside the wound body 110. Thereby, possibility that electrolyte solution will dry locally within the winding body 110 can be reduced. In particular, the hole 113 of the positive electrode sheet 112 is provided at a position overlapping the separator 16 and the like when viewed from the radial direction of the wound body 110. Similarly, the hole 115 of the negative electrode sheet 114 is provided at a position overlapping the separator 16 and the like when viewed from the radial direction of the wound body 110. Thereby, the electrolyte solution that has passed through the holes 113 or 115 immediately contacts the separator 16 or the like. The electrolytic solution in contact with the separator 16 or the like spreads throughout the separator due to capillary action of the separator 16 or the like. By providing the holes 113 and 115 at a position overlapping the separator 16 or the like when viewed from the radial direction of the wound body 110, the electrolyte can be easily spread.
Moreover, by making the core 130 hollow, the electrolyte solution can be stored in the hollow portion of the core 130 at the time of manufacturing the battery. The electrolyte stored in the hollow portion of the core 130 can spread through the holes 113, 115, and 131 to the entire area of the wound body 110. This also prevents the electrolyte from locally drying inside the wound body 110.
The positive electrode terminal 40 is in contact with the end surface of the positive electrode side end portion 110a of the winding body 110, and the negative electrode terminal 50 is in contact with the end surface of the negative electrode side end portion 110b. Therefore, the electrolytic solution cannot move in the radial direction at the positive electrode side end portion 110a or the negative electrode side end portion 110b of the wound body 110. However, the electrolytic solution can move in the radial direction through the holes 113, 115, and 131. It is particularly effective to provide the holes 113, 115, and 131 in a wound battery in which a terminal is in contact with each end face of the wound body 110.

Experiments were conducted to verify the effects of the holes 113, 115, and 131. Three types of specimens were prepared for the experiment. All three types of test specimens are cylindrical batteries (winding batteries) made to a standard size called 18650 (diameter 18 mm (maximum diameter 18.3 mm), length 65 mm). In all three types of test bodies, the wound body and the terminal are in contact at the end face and the side surface of the end of the wound body. The end face of the end of the winding body and the terminal are welded. The side surface of the end of the winding body is caulked by a terminal. The 1st test body does not provide the hole in any of a positive electrode sheet, a negative electrode sheet, and a core. In the second test body, holes having a diameter of 2 mm (holes corresponding to holes 113 and 115 in FIG. 3) were provided at intervals of 4 mm in each of the positive electrode sheet and the negative electrode sheet. The third test body was provided with holes similar to those of the second test body, and a number of mesh holes (holes corresponding to the holes 131 in FIG. 3) were provided on the surface of the core. Each specimen was subjected to a test in which charging and discharging at 1 coulomb was repeated 1000 cycles at an atmospheric temperature of 60 ° C. The change in the capacity of the test body every 100 cycles is shown in FIG. The graph of FIG. 4 shows the capacity of the test specimen every 100 cycles as a percentage when the capacity after the first charge / discharge is 100%.
As shown in FIG. 4, the capacity after 1000 cycles is 66% for the first specimen and 74% and 78% for the second specimen and the third specimen, respectively. In other words, when charging and discharging are repeated 1000 cycles, the capacity of the first test body is reduced by 34%, whereas the second test body and the third test body are suppressed to 26% and 22%, respectively. . It has been demonstrated that by providing a hole in the positive electrode sheet and the negative electrode sheet, and further providing a hole in the core, the performance deterioration of the wound battery can be reduced.

A modification of the above embodiment will be described.
A first modification will be described with reference to FIG. FIG. 5 is a schematic partial perspective view of the wound body 210 of the wound battery according to the first modification. In FIG. 5, the positive terminal 40 is indicated by a virtual line (two-dot chain line). In FIG. 5, the outermost layer of the wound body 210 is the positive electrode sheet 212. Further, the positive electrode side end portion 210 a of the wound body 210 is formed by winding only the extension portion 212 b of the positive electrode sheet 212.
In this modification, a plurality of slits 213 are provided in the extended portion 212 b of the wound positive electrode sheet 212. Each slit 213 extends long in the axial direction of the wound body 210. The end of the slit 213 reaches the edge of the extension 212b. Providing a plurality of slits 213 in the extension 212b can prevent the extension 212b from undulating when the winding body 210 is caulked between the outer periphery of the positive electrode terminal 40 and the core 30. That is, the diameter of the crimped extension portion 212b can be reduced. Thereby, it is possible to prevent the size of the positive electrode terminal 40 in the radial direction (that is, the diameter near the end on the positive electrode terminal side of the wound battery) from increasing. Similarly, it is preferable to provide a slit in the extended portion of the negative electrode sheet.

  A second modification will be described with reference to FIG. FIG. 6 is a schematic partial cross-sectional view of a wound body 310 of a wound battery according to a second modification. In this modification, a recess 332 is provided on the side surface of the core 330. A positive electrode side end portion 310 a of the winding body 310 (the positive electrode side end portion 310 a is formed by an extension portion of the positive electrode sheet) is caulked between the outer peripheral portion of the positive electrode terminal 340 and the recess 332. A recess 342 is provided on the outer periphery of the positive electrode terminal 340. The positive electrode side end portion 310 a of the winding body 310 is caulked between the recess 342 in the outer peripheral portion of the positive electrode terminal 340 and the recess 332 in the core 330. According to this structure, the wound body 310 can be more firmly fixed to the core 330.

Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of purposes at the same time, and has technical utility by achieving one of the purposes.

FIG. 1 is a schematic cross-sectional view of a wound battery according to a first embodiment. FIG. 2 is a cross-sectional view of a wound body of the wound battery according to the first embodiment. FIG. 3 is a cross-sectional view of a wound body of the wound battery according to the second embodiment. FIG. 4 is a graph showing the results of an experiment for verifying the effect of the wound battery according to the second example. FIG. 5 is a schematic perspective view of a wound body of the wound battery according to the first modification. FIG. 6 is a schematic partial cross-sectional view of a wound body of a wound battery according to a second modification.

Explanation of symbols

10: Winding body 12: Positive electrode sheet 14: Negative electrode sheet 16, 18: Separator 20, 22: Active material 30: Core 40: Positive electrode terminal 50: Negative electrode terminal 60: Insulating resin member 70: Case 100: Winding type battery

Claims (7)

A wound body obtained by laminating and winding a positive electrode sheet, a negative electrode sheet, and a separator;
A terminal that contacts the side surface and the end surface at one end of the wound body,
The wound battery according to claim 1, wherein the side surface of the wound body is crimped by a terminal, and the end surface of the wound body is welded to the terminal. The positive electrode sheet, the negative electrode sheet, and the separator are wound around the core,
Either one of the positive electrode sheet and the negative electrode sheet is provided with an extension that extends longer in the axial direction of the winding body than the separator and the other electrode sheet at the end,
The wound battery according to claim 1, wherein the extension portion is caulked between the terminal and the core.   The wound battery according to claim 2, wherein no active material is applied to the extension portion.   The wound battery according to claim 2 or 3, wherein a depression is provided on a side surface of the winding core, and the extension portion is caulked between the terminal and the depression.   5. The wound battery according to claim 2, wherein a slit extending in an axial direction of the wound body is provided in an extension portion of the electrode sheet.   The wound battery according to any one of claims 2 to 5, wherein a hole is provided in at least one of the positive electrode sheet and the negative electrode sheet.   The wound battery according to any one of claims 2 to 6, wherein a hole is provided in a side surface of the winding core.

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