Lug-free battery

Abstract

The electrode roll includes a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode. The positive electrode includes a positive electrode foil extension portion extending from the positive electrode foil. The negative electrode includes a negative electrode foil extension portion extending from the negative electrode foil. The positive electrode, the negative electrode, and the separator are wound into a spiral defining a through-hole, and have a central axis extending through the through-hole. The positive electrode foil extension portion and the negative electrode foil extension portion extend from opposite end portions of the electrode winding body. A part of the positive electrode foil extension portion includes a bent portion bent toward the central axis such that the part of the positive electrode foil extension portion overlaps and defines the first surface. A part of the negative electrode foil extension portion includes a bent portion bent toward the central axis such that the part of the negative electrode foil extension portion overlaps and defines the second surface.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Patent Application No. 63 / 456,113, filed March 31, 2023. The entire contents of this application are incorporated herein by reference. Technical Field

[0003] This invention relates to a battery. More specifically, this invention relates to a tabless rechargeable battery. Background Technology

[0004] Lithium-ion rechargeable batteries were developed for applications requiring high output, such as power tools and automobiles. One method to achieve high output is high-speed discharge, which involves a relatively large current flowing through the battery. However, this high-speed discharge results in excessively large current, leading to an increase in the battery's internal resistance.

[0005] For example, in existing battery technology, in order to collect current from the ends of the wound foil as a whole, the welding points are densely packed towards the center. Therefore, simply bending the foil to overlap it creates a region with little foil overlap on the central side of the electrode assembly, resulting in openings during welding. Furthermore, when welding the bottom of the can during the assembly process, sufficient space is required in the center of the electrode assembly. If the foil is folded back from the outer periphery to the center, the space in the central area formed during winding is blocked, making assembly impossible. Summary of the Invention

[0006] To overcome the above problems, an exemplary embodiment of the present invention provides a battery that includes bent portions in both the positive and negative electrode foils, provides high-rate discharge, and is reliably weldable.

[0007] According to an exemplary embodiment of the present invention, an electrode winding includes a positive electrode, a negative electrode, and a separator between the positive and negative electrodes. The positive electrode includes: a positive electrode foil; a positive electrode active material on a portion of the positive electrode foil; and a positive electrode foil extension extending from the positive electrode foil. The positive electrode active material is not on the positive electrode foil extension. The negative electrode includes: a negative electrode foil; a negative electrode active material on a portion of the negative electrode foil; and a negative electrode foil extension extending from the negative electrode foil. The negative electrode active material is not on the negative electrode foil extension. The positive electrode, negative electrode, and separator are wound into a helix defining a through-hole, through which a central axis extends. The positive electrode foil extends from a first end of the electrode winding. The negative electrode foil extends from a second end opposite to the first end of the electrode winding. A portion of the positive electrode foil extension includes a first bend that bends toward the central axis such that a portion of the positive electrode foil extension overlaps and defines a first surface. The positive electrode foil extension includes a first groove on the first surface. A portion of the negative electrode foil extension includes a second bend that bends toward a central axis in such a manner that the portion of the negative electrode foil extension overlaps with and defines a second surface. The negative electrode foil extension includes a second groove on the second surface.

[0008] The bottom surface of the first groove can be bent, and the bottom surface of the second groove can be bent. The first curvature of the first groove can be less than the second curvature of the second groove.

[0009] The second groove may be deeper than the first groove. Both the first and second grooves may have a rectangular cross-section. A portion of the separator may include a third bend. A portion of the positive electrode active material may include a fourth bend, and a portion of the negative electrode active material may include a fifth bend. A portion of the positive electrode foil and / or a portion of the negative electrode foil may be folded onto the innermost portion of the separator closest to the through-hole.

[0010] A portion of the positive electrode foil extension may include a plurality of first bends, and a portion of the negative electrode foil extension may include a plurality of second bends. The number of the plurality of first bends in the positive electrode foil extension may be greater than the number of the plurality of second bends in the negative electrode foil extension. The first bend shape of the first bend of the positive electrode foil extension may be asymmetrical with respect to the central axis, and the second bend shape of the second bend of the negative electrode foil extension may be asymmetrical with respect to the central axis. The electrode winding may also include voids between adjacent first bends in the radial direction of the positive electrode foil extension or between adjacent second bends in the radial direction of the negative electrode foil extension.

[0011] The first surface can be a substantially smooth surface with a glossy appearance, and the second surface can be a substantially smooth surface with a glossy appearance.

[0012] The first distance between adjacent portions in the radial direction of the positive electrode foil extension can decrease as the second distance to the negative electrode active material increases, and the third distance between adjacent portions in the radial direction of the negative electrode foil extension can decrease as the fourth distance to the positive electrode active material increases.

[0013] The first distance between adjacent portions in the radial direction of the positive electrode foil extension can decrease as the second distance to the through hole decreases, and the third distance between adjacent portions in the radial direction of the negative electrode foil extension can decrease as the fourth distance to the through hole decreases.

[0014] The degree of fit between adjacent portions in the radial direction of the positive electrode foil extension can increase as the first distance to the through hole decreases, and the degree of fit between adjacent portions in the radial direction of the negative electrode foil extension can increase as the second distance to the through hole decreases.

[0015] According to an exemplary embodiment of the invention, the battery includes: an outer can; and an electrode winding within the outer can, according to various other exemplary embodiments of the invention.

[0016] The battery may also include a positive current collector plate that is joined to a first surface and includes a first flat fan-shaped portion and a first rectangular strip-shaped portion, and may also include a negative current collector plate that is joined to a second surface and includes a second flat fan-shaped portion and a second rectangular strip-shaped portion.

[0017] After the positive current collector plate and the negative current collector plate are respectively joined to the first surface and the second surface, the first groove may not maintain its cross-sectional shape, while the second groove may maintain its cross-sectional shape.

[0018] The first sector of the positive current collector may include a first curved portion and two first straight portions, wherein the two first straight portions are the same straight line. The second sector of the negative current collector may include a second curved portion and two second straight portions, wherein the two second straight portions are the same straight line.

[0019] The first flat sector and the first rectangular strip of the positive current collector can be connected at two first curved corners, and the second flat sector and the rectangular strip of the negative current collector can be connected at two second curved corners.

[0020] The battery may also include a positive insulator that is coupled to a positive current collector, including a large hole aligned with a through hole and a small hole disposed around the large hole, and may also include a negative insulator that is coupled to a negative current collector, including a hole aligned with a through hole.

[0021] According to an exemplary embodiment of the present invention, an electrode winding includes a positive electrode, a negative electrode, and a separator between the positive and negative electrodes. The positive electrode includes: a positive electrode foil; a positive electrode active material disposed on a portion of the positive electrode foil; and a positive electrode foil extension extending from the positive electrode foil. The positive electrode active material is not on the positive electrode foil extension. The negative electrode includes: a negative electrode foil; a negative electrode active material on a portion of the negative electrode foil; and a negative electrode foil extension extending from the negative electrode foil. The negative electrode active material is not on the negative electrode foil extension. The positive electrode, negative electrode, and separator are wound into a helix defining a through-hole, through which a central axis extends. The positive electrode foil extends from a first end of the electrode winding. The negative electrode foil extends from a second end opposite to the first end of the electrode winding. A portion of the positive electrode foil extension includes a first bend that bends toward the central axis such that a portion of the positive electrode foil extension overlaps with a defined first surface. The first bend shape of the first bend of the positive electrode foil extension may be asymmetrical relative to the central axis. A portion of the negative electrode foil extension includes a second bend that bends toward a central axis in such a way that the portion of the negative electrode foil extension overlaps with and defines a second surface. The second bend shape of the second bend of the negative electrode foil extension may be asymmetrical relative to the central axis.

[0022] A portion of the positive electrode foil extension may include multiple first bends, and a portion of the negative electrode foil extension may include multiple second bends. The number of first bends in the positive electrode foil extension may be greater than the number of second bends in the negative electrode foil extension. A portion of the separator may include a third bend. A portion of the positive electrode active material may include a fourth bend, and a portion of the negative electrode active material may include a fifth bend. A portion of the positive electrode foil and / or a portion of the negative electrode foil may be bent to the innermost portion of the separator closest to the through-hole.

[0023] The positive electrode foil extension includes a first groove disposed on a first surface, and the negative electrode foil extension includes a second groove disposed on a second surface. The bottom surface of the first groove is bendable, and the bottom surface of the second groove is bendable.

[0024] The first curvature of the first groove can be less than the second curvature of the second groove. The second groove can be deeper than the first groove.

[0025] The first slot and the second slot can each have a rectangular cross-section.

[0026] The electrode winding may also include voids between adjacent first bends in the radial direction of the positive electrode foil extension or between adjacent second bends in the radial direction of the negative electrode foil extension.

[0027] The first surface can be a substantially smooth surface with a glossy appearance, and the second surface can be a substantially smooth surface with a glossy appearance.

[0028] The first distance between adjacent portions in the radial direction of the positive electrode foil extension can decrease as the second distance to the negative electrode active material increases, and the third distance between adjacent portions in the radial direction of the negative electrode foil extension can decrease as the fourth distance to the positive electrode active material increases.

[0029] The first distance between adjacent portions in the radial direction of the positive electrode foil extension can decrease as the second distance to the through hole decreases, and the third distance between adjacent portions in the radial direction of the negative electrode foil extension can decrease as the fourth distance to the through hole decreases.

[0030] The degree of fit between adjacent portions in the radial direction of the positive electrode foil extension can increase as the first distance to the through hole decreases, and the degree of fit between adjacent portions in the radial direction of the negative electrode foil extension can increase as the second distance to the through hole decreases.

[0031] According to an exemplary embodiment of the invention, the battery includes: an outer can; and an electrode winding within the outer can, according to various other exemplary embodiments of the invention.

[0032] The battery may also include a positive current collector plate that is joined to a first surface and includes a first flat fan-shaped portion and a first rectangular strip-shaped portion, and may also include a negative current collector plate that is joined to a second surface and includes a second flat fan-shaped portion and a second rectangular strip-shaped portion.

[0033] After the positive current collector plate and the negative current collector plate are respectively joined to the first surface and the second surface, the first groove may not maintain its cross-sectional shape, while the second groove may maintain its cross-sectional shape.

[0034] The first sector of the positive current collector may include a first curved portion and two first straight portions, wherein the two first straight portions are the same straight line. The second sector of the negative current collector may include a second curved portion and two second straight portions, wherein the two second straight portions are the same straight line.

[0035] The first flat sector and the first rectangular strip of the positive current collector can be connected at two first curved corners, and the second flat sector and the rectangular strip of the negative current collector can be connected at two second curved corners.

[0036] The battery may also include a positive insulator that is coupled to a positive current collector, including a large hole aligned with a through hole and a small hole disposed around the large hole, and may also include a negative insulator that is coupled to a negative current collector, including a hole aligned with a through hole.

[0037] The above and other features, elements, characteristics, steps and advantages of the present invention will become more apparent from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings.

[0038] The documents of this patent or patent application shall include at least one color drawing. A copy of the publication of this patent or patent application, including the color drawing, shall be provided by the Japanese domestic authorities upon request for payment and the necessary processing fees. Attached Figure Description

[0039] Figure 1 This is a schematic diagram showing the cross-section of the battery.

[0040] Figure 2 This is a schematic diagram illustrating an example of the relationship between the positive electrode, negative electrode, and diaphragm in an electrode winding.

[0041] Figure 3A This is a top view of the positive current collector.

[0042] Figure 3B This is a top view of the negative current collector.

[0043] Figures 4A to 4F This is a schematic diagram showing the process of assembling a battery.

[0044] Figure 5A It is shown Figures 6A to 9D A schematic diagram of the negative electrode side of a battery with various cross-sections shown.

[0045] Figure 5B It is shown Figures 6A to 9D The various cross-sections of the wires shown are related to the negative electrode side of the battery. Figure 5A The corresponding photo.

[0046] Figure 6A It is a schematic diagram of a cross-section of the positive electrode side of the battery along the groove extending from the positive electrode foil.

[0047] Figure 6B It is a schematic diagram of a cross-section of the negative electrode side of the battery along the groove extending from the negative electrode foil.

[0048] Figure 6C It is the cross-section of the positive electrode side of the battery along the groove extending from the positive electrode foil. Figure 6A The corresponding photo.

[0049] Figure 6D It is the cross-section of the negative electrode side of the battery along the groove extending from the negative electrode foil. Figure 6B The corresponding photo.

[0050] Figure 7A yes Figure 6A A close-up overview.

[0051] Figures 7B to 7D yes Figure 7A A close-up drawing of a portion of the photographs.

[0052] Figure 7E yes Figure 6B A close-up overview.

[0053] Figures 7F to 7H yes Figure 7E A close-up drawing of a portion of the photographs.

[0054] Figure 7I Is with Figure 7A The corresponding photo.

[0055] Figure 7J Is with Figure 7E The corresponding photo.

[0056] Figure 8A It is a schematic diagram of a cross-section of the positive electrode side of a battery that includes the positive electrode foil extension but not along the groove of the positive electrode foil extension.

[0057] Figures 8B to 8D yes Figure 8A A close-up drawing of a portion of the photographs.

[0058] Figure 8E It is a schematic diagram of a cross-section of the negative electrode side of a battery that includes the negative electrode foil extension but does not follow the groove along the negative electrode foil extension.

[0059] Figures 8F to 8H yes Figure 8E A close-up drawing of a portion of the photographs.

[0060] Figure 8I Is with Figure 8A The corresponding photo.

[0061] Figure 8J Is with Figure 8E The corresponding photo.

[0062] Figure 9A It is a schematic diagram of a cross-section of the positive electrode side of a battery that runs through the welding line that joins the positive electrode foil extension and the positive electrode current collector, and through multiple grooves in the positive electrode foil extension.

[0063] Figure 9B It is a schematic diagram of a cross-section of the negative electrode side of a battery that runs through the welding line that joins the negative electrode foil extension and the negative electrode current collector, and through multiple slots in the negative electrode foil extension.

[0064] Figure 9C Is with Figure 9A The corresponding photo.

[0065] Figure 9D Is with Figure 9B The corresponding photo.

[0066] Figure 10A This is a schematic diagram of the positive terminal of a battery, including the positive electrode foil extension.

[0067] Figure 10B Is with Figure 10A The corresponding photo.

[0068] Figure 11A This is a schematic diagram of the negative terminal of a battery, including the negative electrode foil extension.

[0069] Figure 11B Is with Figure 11A The corresponding photo.

[0070] Figure 12A This is a schematic diagram of the positive terminal of the battery, showing the welding wires of the positive current collector plate.

[0071] Figure 12B This is a schematic diagram of the negative terminal of the battery, showing the welding lines of the positive and negative current collector plates.

[0072] Figure 12C yes Figure 12A A close-up schematic diagram of the welding wires in the positive current collector plate.

[0073] Figure 12D yes Figure 12A A schematic diagram of the cross-section of the welding wire of the positive current collector plate.

[0074] Figures 12E to 12H Is with Figures 12A-12D The corresponding photo.

[0075] Figure 13A This is a schematic diagram of the insulators at both ends of the electrode winding.

[0076] Figure 13B as well as Figure 13C This is a schematic diagram of the insulator on the positive side of the electrode winding.

[0077] Figure 13D as well as Figure 13E This is a schematic diagram of the insulator on the negative side of the electrode winding.

[0078] Figures 13F to 13I Is with Figures 13B-13E The corresponding photo.

[0079] Figure 14A This is a schematic diagram of the positive and negative insulating plates located at the ends of the electrode winding body.

[0080] Figure 14B as well as Figure 14C This is a schematic diagram of a positive electrode insulating plate disposed at the positive end of the electrode winding body.

[0081] Figure 14Das well as Figure 14E This is a schematic diagram of a negative insulating plate located at the negative end of the electrode winding body.

[0082] Figures 14F to 14I Is with Figures 14B to 14E The corresponding photo.

[0083] Figure 15A This is a schematic diagram of the positive current collector located at the positive end of the electrode winding body.

[0084] Figure 15B This is a schematic diagram of the negative current collector located at the negative end of the electrode body.

[0085] Figure 15C as well as Figure 15D Is with Figure 15A as well as Figure 15B The corresponding photo. Detailed Implementation

[0086] Figure 1 This is a schematic cross-sectional view of battery 1. Figures 5A to 13I Including with Figure 1 A schematic diagram and photograph of the battery corresponding to battery 1.

[0087] Battery 1 can be any rechargeable battery, such as a cylindrical lithium-ion battery. Alternatively, batteries other than lithium-ion batteries or batteries other than cylindrical shapes can also be used.

[0088] like Figure 1 As shown, the battery 1 may include an electrode winding 20 housed inside the outer can 11. Specifically, the battery 1 may include, for example, a pair of insulating plates 12 and 13 and the electrode winding 20 inside the cylindrical outer can 11. In addition, the battery 1 may include, for example, any one or more of the following inside the outer can 11: a PTC (Positive Temperature Coefficient) element, reinforcing components, etc.

[0089] The outer can 11 houses the electrode winding 20. The outer can 11 can be a cylindrical container with an open end and a closed end. That is, the outer can 11 can include an open end 11N. The outer can 11 can, for example, contain one or more metallic materials such as iron, aluminum, and their alloys. The surface of the outer can 11 can, for example, be plated with one or more metallic materials such as nickel.

[0090] Insulating plates 12 and 13 may each be, for example, disc-shaped plates having a surface that is perpendicular or substantially perpendicular to the winding axis of the electrode winding 20 within manufacturing and / or measurement tolerances; that is, having a surface that is perpendicular to the winding axis of the electrode winding 20 within manufacturing and / or measurement tolerances. Figure 1The Z-axis is perpendicular or substantially perpendicular to the surface. Furthermore, the insulating plates 12 and 13 can clamp the electrode winding 20 between them.

[0091] The open end 11N of the outer can 11 may include, for example, a battery cover 14 and a safety valve 30 pressed together by a gasket 15. The battery cover 14 functions as a "cover component," and the gasket 15 functions as a "sealing component." Thus, with the electrode winding body 20 and the like housed within the outer can 11, the outer can 11 is sealed. Therefore, the open end 11N of the outer can 11 includes a press-fit structure (press-fit structure 11R) formed by pressing the battery cover 14 and the safety valve 30 together by the gasket 15. More specifically, the bend 11P is the so-called press-fit portion, and the press-fit structure 11R is the so-called press-fit structure.

[0092] The battery cover 14 primarily closes the open end 11N of the outer can 11 while the electrode winding body 20 and the like are housed within the outer can 11. The battery cover 14 may, for example, be made of the same material as the outer can 11. The central region of the battery cover 14 protrudes, for example, in the +Z direction. Therefore, the region outside the central region of the battery cover 14 (the peripheral region) contacts, for example, the safety valve 30.

[0093] The gasket 15 is mainly sandwiched between the outer can 11 (bent portion 11P) and the battery cover 14, and can seal the gap between the bent portion 11P and the battery cover 14. However, the surface of the gasket 15 can also be coated with asphalt, for example.

[0094] The gasket 15 may contain one or more insulating materials. The type of insulating material is not particularly limited; examples include polymers such as polybutylene terephthalate (PBT) and polypropylene (PP). In particular, polybutylene terephthalate is an example of an insulating material. This is because the gap between the bent portion 11P and the battery cover 14 is sufficiently sealed, and the outer casing 11 and the battery cover 14 are electrically separated.

[0095] Safety valve 30 is mainly used to release the pressure (internal pressure) inside the outer tank 11 by releasing the sealed state of the outer tank 11 as needed when the internal pressure rises. Reasons for the rise in internal pressure in the outer tank 11 include, for example, gases produced by the decomposition reaction of the electrolyte during charging and discharging.

[0096] In battery 1, a strip-shaped positive electrode 21 and a strip-shaped negative electrode 22 are wound into a spiral shape with a separator 23 between them, impregnated with electrolyte, and housed in an outer can 11. The positive electrode 21 can be obtained by forming a positive electrode active material layer 21B on a portion of one or both sides of a positive electrode foil 21A. Examples of materials for the positive electrode foil 21A include, for example, a metal foil made of aluminum or an aluminum alloy. For example, the positive electrode foil 21A can be an aluminum foil with a thickness of approximately 12 μm within manufacturing and / or measurement tolerances. The negative electrode 22 can be obtained by forming a negative electrode active material layer 22B on a portion of one or both sides of a negative electrode foil 22A. The material for the negative electrode foil 22A can be, for example, a metal foil made of nickel, a nickel alloy, copper, or a copper alloy. For example, the negative electrode foil 22A can be a copper foil with a thickness of approximately 8 μm within manufacturing and / or measurement tolerances. The diaphragm 23 may include a porous and insulating membrane that, while electrically insulating the positive electrode 21 and the negative electrode 22, allows substances such as ions and electrolytes to move.

[0097] The positive electrode active material layer 21B and the negative electrode active material layer 22B cover most of the positive electrode foil 21A and the negative electrode foil 22A, respectively, but intentionally do not cover the peripheral portion of one end of the strip in the short axis direction. Furthermore, the portion extending from the positive electrode foil 21A or the negative electrode foil 22A but not covered by the positive electrode active material layer 21B or the negative electrode active material layer 22B is called the positive electrode foil extension 21C or the negative electrode foil extension 22C. In the battery 1, the electrode winding body 20 is wound in a manner that specifies a through hole 26 having a central axis.

[0098] Figure 2 This shows an example of a structure with a positive electrode 21, a negative electrode 22, and a separator 23 stacked before winding. The positive electrode foil extension 21C of the positive electrode 21... Figure 2 The shaded area on the upper side of the middle part has a width represented by A, and the negative electrode foil extension 22C of the negative electrode 22 (in the middle part) has a width represented by A. Figure 2 The shaded portion (lower side) has a width represented by B. The relationship A > B can be satisfied, for example, A = 7 mm, B = 4 mm, but other dimensions are also possible. The portion of the positive electrode foil extension 21C of the positive electrode 21 protruding from one end of the separator 23 in the width direction has a length represented by C, and the portion of the negative electrode foil extension 22C of the negative electrode 22 protruding from the other end of the separator 23 in the width direction has a length represented by D. The relationship C > D can be satisfied, for example, C = 4.5 mm, D = 3 mm, but other dimensions are also possible. The complete stack of the positive electrode 21, negative electrode 22, and separator 23 can have a width represented by G. The length of the positive electrode foil extension 21C extending from the complete stack can be represented by E, and the length of the negative electrode foil extension 22C extending from the complete stack can be represented by F. The relationship E < F can be satisfied, for example, E = 3.5 mm, F = 4.5 mm, but other dimensions are also possible.

[0099] The positive foil extension 21C of the positive electrode 21 can be made of aluminum, for example, while the negative foil extension 22C of the negative electrode 22 can be made of copper, for example. Therefore, the positive foil extension 21C of the positive electrode 21 is typically softer (lower Young's modulus) than the negative foil extension 22C of the negative electrode 22. Thus, the relationships A > B and C > D can be satisfied, and when the positive foil extension 21C of the positive electrode 21 and the negative foil extension 22C of the negative electrode 22 are bent simultaneously from both sides with the same pressure, the height of the bends measured from the ends of the separator 23 for both the positive and negative electrodes can be made to be the same. The positive foil extension 21C can be bent such that the bends of adjacent portions in the radial direction overlap, thus facilitating the connection between the positive foil extension 21C and the current collector 24. Furthermore, the negative electrode foil extension 22C can be bent such that the bends of adjacent portions in the radial direction of the negative electrode foil extension 22C overlap, thereby facilitating the joining of the negative electrode foil extension 22C and the current collector 25. Joining refers to laser welding-based joining, but the joining method is not limited to laser welding. The shapes of different bends in the positive electrode foil extension 21C and the negative electrode foil extension 22C can also be different. For example, the shape of the bend in the positive electrode foil extension 21C can be asymmetrical relative to the central axis through the through hole 26, and the shape of the bend in the negative electrode foil extension 22C can also be asymmetrical relative to the central axis through the through hole 26. When the positive and negative electrode foil extensions 21C and 22C are bent, the separator 23 can be bent. Furthermore, if the positive and negative electrode foil extensions 21C and 22C are bent, the positive electrode active material layer 21B and / or the negative electrode active material layer 22B may also be bent.

[0100] For the positive electrode 21, a portion approximately 3 mm wide, including the boundary between the positive electrode foil extension 21C and the positive electrode active material layer 21B, within the range of manufacturing tolerances and / or measurement tolerances, is covered by the insulating layer 101. Figure 2 The gray area is covered. Furthermore, the entire area of ​​the positive electrode foil extension 21C of the positive electrode 21, which sandwiches the separator 23 and faces the negative electrode active material layer 22B of the negative electrode 22, is covered by the insulating layer 101. The insulating layer 101 has the effect that even if foreign objects enter between the negative electrode active material layer 22B of the negative electrode 22 and the positive electrode foil extension 21C of the positive electrode 21, an internal short circuit of the battery 1 is reliably prevented. In addition, the insulating layer 101 has the effect that in the event of an impact on the battery 1, it absorbs the impact and reliably prevents the positive electrode foil extension 21C of the positive electrode 21 from bending or short-circuiting with the negative electrode 22.

[0101] The central axis of the electrode winding 20 extends through a through hole 26. The through hole 26 is a hole through which the core and welding electrode rod can be inserted. The electrode winding 20 is wound in an overlapping manner such that the positive foil extension 21C of the positive electrode 21 and the negative foil extension 22C of the negative electrode 22 extend from the electrode winding 20 in opposite directions. Therefore, the positive foil extension 21C of the positive electrode 21 is located at the end 41 of the electrode winding 20, and the negative foil extension 22C of the negative electrode 22 is located at the end 42 of the electrode winding 20. In order to improve the contact with the current collectors 24 and 25 used to extract current, the positive and negative foil extensions 21C and 22C can be bent in such a way that the ends 41 and 42 can be defined as substantially flat surfaces within manufacturing tolerances. The bending direction is from the outer edges 27 and 28 of ends 41 and 42 toward the through hole 26. In the wound state, the adjacent peripheral positive foil extensions 21C and negative foil extensions 22C are bent in a manner that overlaps each other, defining a substantially smooth surface within manufacturing tolerances and possessing a glossy appearance. The specular gloss Gs(60°) of the substantially smooth surface can be measured according to JIS Z 8741:1997, where the incident angle of light is 60°. For example, the specular gloss Gs(60°) of a glass surface with a refractive index of 1.567 is 100. The surface can be substantially flat or have raised portions. In any case, even if some unevenness exists on the surface, a substantially smooth surface can be formed to a degree that does not affect the bonding with the current collector 24 or current collector 25.

[0102] The positive electrode foil extension 21C can be bent so that a portion of the bent portion of the positive electrode foil extension 21C overlaps, so that the end 41 can be defined as a flat surface. Similarly, the negative electrode foil extension 22C can be bent so that a portion of the bent portion of the negative electrode foil extension 22C overlaps, so that the end 42 can be defined as a flat surface. By bending the positive and negative electrode foil extensions 21C and 22C, bends, wrinkles, folds, gaps, or voids can be formed at the ends 41 and 42. For example, Figure 7B as well as Figure 7H The hole 44 is shown between the creases of the positive and negative electrode foil extensions 21C and 22C that bend in opposite directions. For example, when the positive electrode foil 21A is softer than the negative electrode foil 22A (i.e., has a lower Young's modulus) and / or when the length of the positive electrode foil extension 21C from the fully stacked body is shorter than the length of the negative electrode foil extension 22C from the fully stacked body, the number of bends, wrinkles or folds of the positive electrode foil 21A may be greater than the number of bends, wrinkles or folds of the negative electrode foil 22A.

[0103] Slot 43 (for example, refer to) Figure 4BThe slot 43 can be formed in the radial direction of the electrode winding body 20 with the through hole 26 as the center. The slot 43 can extend from the outer edges 27, 28 of the ends 41, 42 to the through hole 26. The central axis of the electrode winding body 20 extends through the through hole 26, which is used as a hole for inserting welding tools when assembling the battery 1. If the slot 43 is formed on the flat surface before bending the positive electrode foil extension 21C and the negative electrode foil extension 22C, the slot 43 can be retained on the flat surface even after bending the positive electrode foil extension 21C and the negative electrode foil extension 22C, and the part without the slot 43 can be joined (welded, etc.) to the positive electrode current collector 24 or the negative electrode current collector 25. Not only the slot 43, but also a part of the flat surface can be joined to the positive electrode current collector 24 or the negative electrode current collector 25.

[0104] Figure 5A as well as Figure 5B Showing with Figure 1 The schematic diagram shows the negative electrode side of battery 1. Figure 5A as well as Figure 5B Show Figures 6A to 9D The lines of the sectional view. Figure 5A as well as Figure 5B A battery 1 is shown with a negative electrode current collector 25 having a cover groove 43.

[0105] Figures 6A to 6D The positive and negative electrode sides of battery 1 are shown along the grooves 43 of the positive and negative electrode foil extensions 21C and 22C. Figures 6A to 6D This demonstrates the ability to bend the bottom of the groove 43, making the groove 43 on the negative electrode side deeper than the groove 43 on the positive electrode side. For example... Figure 6A as well as Figure 6C As shown, the groove 43 on the positive electrode side of battery 1 can be approximately 0.4 mm within the range of manufacturing tolerances and / or measurement tolerances, but it can also be other values. Furthermore, as... Figure 6B as well as Figure 6D As shown, the groove 43 on the negative electrode side of battery 1 can be approximately 0.8 mm within the range of manufacturing tolerances and / or measurement tolerances, but it can also be other values. The bending shapes of the positive and negative electrode foil extensions 21C and 22C can be asymmetrical relative to the central axis extending through the through hole 26.

[0106] Figures 7A to 7J A close-up view of the positive and negative sides of the battery 1 is shown, along the grooves 43 extending from the positive and negative electrode foils 21C and 22C. Figures 7A to 7JAs shown, the positive and negative electrode foil extensions 21C and 22C include bends as described above. The process of forming bends in the positive and negative electrode foil extensions 21C and 22C can form bends in portions of the separator 23 near the positive and negative electrode foil extensions 21C and 22C, and can also create bends in portions of the positive and negative electrode active material layers 21B and 22B near the positive and negative electrode foil extensions 21C and 22C. A void or gap can be created between a portion of the positive electrode foil 21A adjacent to a portion of the negative electrode foil 22A in the radial direction. A portion of the positive electrode foil 21A and / or a portion of the negative electrode foil 22A can be folded back to the innermost portion of the separator 23 in such a way that the portion of the positive electrode foil 21A and / or the portion of the negative electrode foil 22A just reaches the through-hole 26. Depending on the application, a portion of the positive electrode foil 21A and / or a portion of the negative electrode foil 22A may be present inside the through-hole 26, but in other applications, a portion of the positive electrode foil 21A and a portion of the negative electrode foil 22A may not be present inside the through-hole 26. For example, if the fixing rod is inserted into the through hole 26 while the positive electrode foil extension 21C and the negative electrode foil extension 22C are bent, the fixing rod can prevent the positive electrode foil 21A and / or the negative electrode foil 22A from existing in the through hole 26.

[0107] Figures 8A to 8J A cross-section of the positive and negative electrode sides of a battery 1 is shown, including positive and negative electrode foil extensions 21C and 22C but not along the groove 43 of the positive and negative electrode foil extensions 21C and 22C. Figures 8A to 8D as well as Figure 8I This illustrates a situation where adjacent portions of the positive electrode foil extension 21C in the radial direction can become closer together as they move further away from the negative electrode active material layer 22B (i.e., the distance between adjacent portions of the positive electrode foil extension 21C in the radial direction decreases as the distance to the negative electrode active material layer 22B increases), and Figures 8E to 8H as well as Figure 8J This illustrates a situation where adjacent portions of the negative electrode foil extension 22C in the radial direction can become closer together as they move further away from the positive electrode active material layer 21B (i.e., the distance between adjacent portions of the negative electrode foil extension 22C in the radial direction decreases as the distance from the positive electrode active material layer 21B increases). In other words, Figures 8A to 8D as well as Figure 8I As shown, the further away from the stack of the positive electrode 21, the separator 23, and the negative electrode 22, the closer adjacent portions of the positive electrode foil extension 21C in the radial direction can be (i.e., Figures 8A to 8D as well as Figure 8I As shown, the further away from the stack of positive electrode 21, separator 23, and negative electrode 22, the closer adjacent portions of the positive electrode foil extension 22C in the radial direction can be (the distance between adjacent portions of the positive electrode foil extension 21C in the radial direction decreases as the distance to the stack of positive electrode 21, separator 23, and negative electrode 22 increases). Figures 8E to 8H as well as Figure 8J This illustrates a situation where adjacent portions of the negative electrode foil extension 22C in the radial direction can become closer together as they move further away from the stack of the positive electrode 21, the separator 23, and the negative electrode 22 (i.e., the distance between adjacent portions of the negative electrode foil extension 22C in the radial direction decreases as the distance from the positive electrode active material layer 21B increases). Furthermore, as... Figures 8A to 8D as well as Figure 8I As shown, in adjacent portions of the positive electrode foil extension 21C in the radial direction, they can become closer together as they approach the through hole 26 (i.e., the distance between adjacent portions of the positive electrode foil extension 21C in the radial direction decreases as the distance to the through hole 26 decreases), such as Figures 8E to 8H As shown in 8J, adjacent portions of the negative electrode foil extension 22C in the radial direction can become closer together as they approach the through hole 26 (i.e., the distance between adjacent portions of the negative electrode foil extension 22C in the radial direction decreases as the distance to the through hole 26 decreases). When the fitting degree includes the number of overlaps of adjacent portions in the radial direction, the overlap length of adjacent portions in the radial direction, and the number of times adjacent portions in the radial direction are clamped together, such as... Figures 8A to 8D As shown in 8I, the degree of fit between adjacent portions in the radial direction of the positive electrode foil extension 21C can be greater the closer it is to the through hole 26. Then, as... Figures 8E to 8H As shown in 8J, the degree of fit between adjacent portions in the radial direction of the negative electrode foil extension 22C can be greater as it gets closer to the through hole 26.

[0108] Figures 9A to 9D The cross-sections of the positive and negative electrode sides of the battery 1, which are shown after the positive and negative electrode foil extensions 21C and 22C are welded to the current collector 24 or 25, and which traverse the welding line and multiple slots 43, are shown. Figure 9B as well as Figure 9D As shown, the cross-section of groove 43 can maintain a rectangular shape even after welding. However, if a softer metal (i.e., with a lower Young's modulus) is used for the positive electrode foil 21A or the negative electrode foil 22A, groove 43 may lose its shape during further processing of the battery 1. Figure 9A , Figure 9C In the first case, soft aluminum is used as the positive electrode foil 21A on the positive electrode side. Therefore, the groove 43 of the positive electrode foil 21A is flattened and cannot maintain its shape, resulting in an indistinct cross-sectional shape after welding. When a harder metal (i.e., a metal with a higher Young's modulus) is used for the positive electrode foil 21A or the negative electrode foil 22A, the groove 43 is able to maintain its shape during further processing of the battery 1. Figure 9B as well as Figure 9D In this process, a harder copper is used as the negative electrode foil 22A on the negative electrode side. As a result, it can be clearly observed that the groove 43 of the negative electrode foil 22A retains its shape and maintains its cross-sectional shape after welding.

[0109] Figure 10A as well as Figure 10B The positive terminal 41 of the battery 1 without the electrode current collector 24 is shown. Figure 11A and Figure 11B The negative terminal 42 of the battery 1 without the electrode current collector 25 is shown. Figure 10A as well as Figure 10B The end 41 of the battery 1, which has a groove 43 formed and a positive electrode foil extension 21C bent, is shown. Figure 11A and Figure 11B The image shows the end 42 of battery 1, after the groove 43 has been formed, and the end 42 after the negative electrode foil extension 22C has been bent. (See image) Figures 10A to 11B As shown, the ends 41 and 42 are specified to have substantially smooth surfaces with a glossy appearance within the manufacturing tolerances.

[0110] Figure 12A And 12E shows a positive current collector 24 with welded wires. Figure 12B Figure 12F shows a negative current collector with weld lines. The groove 43 below the positive and negative current collectors 24 and 25 is indicated by dashed lines. The weld lines can extend radially with the center as the central axis of the through-hole 26. Each weld line may include more than two sub-lines. Figure 12C , 12D 12G and 12H show six secondary lines extending parallel or substantially parallel within manufacturing and / or measurement tolerances, but any number of secondary lines can also be used. Therefore, multiple welding lines can be included between adjacent slots 43.

[0111] In known lithium-ion secondary batteries, current collector leads are welded to the positive electrode 21 and the negative electrode 22, respectively. However, the internal resistance of the battery is high, and the temperature rises due to the heat generated during discharge, making it unsuitable for high-rate discharge. Therefore, in battery 1, the positive current collector plate 24 and the negative current collector plate 25 are disposed at the ends 41 and 42, and the positive foil extension 21C and the negative foil extension 22C at the ends 41 and 42 are welded at multiple locations, thereby reducing the internal resistance of the battery. The ends 41 and 42 can be bent in a manner that specifies substantially flat surfaces within manufacturing tolerances, which also helps to reduce resistance.

[0112] Figure 3A and Figure 3B Examples of current collectors 24 and 25 are shown. Figure 3A The positive current collector 24 is shown. Figure 3B The negative current collector 25 is shown. The positive current collector 24 is, for example, a metal plate made of aluminum, aluminum alloy, or a composite thereof, and the negative current collector 25 is, for example, a metal plate made of nickel, nickel alloy, copper, copper alloy, or a composite thereof. Figure 3A , Figure 15A as well as Figure 15C As shown, the positive current collector 24 includes a flat fan-shaped portion 31 and a rectangular strip-shaped portion 32. The flat fan-shaped portion 31 and the rectangular strip-shaped portion 32 can be connected by defining two corners 48. Figure 3A , Figure 15A as well as Figure 15C As shown, the two corner portions 48 are each flexible. The sector portion 31 includes a hole 35 near its center, which is located at a position corresponding to the through hole 26, thus aligning the hole 35 with the through hole 26. The sector portion 31 includes a curved portion and two straight portions. Figure 3A , Figure 15A as well as Figure 15C As shown, the lines 49 of the two straight sections can be the same straight line or substantially the same straight line within the range of manufacturing tolerances and / or measurement tolerances. Figure 3A The shaded area is the insulating portion 32A, to which insulating tape is attached or coated with insulating material. Below the shaded portion is the connecting portion 32B, which connects to the sealing plate that also serves as an external terminal. In a battery structure where a metal center pin (not shown) is not provided in the through hole 26, the probability of the strip portion 32 contacting the portion with a negative electrode potential is low, and the insulating portion 32A is unnecessary. In this case, the width of the positive electrode 21 and the negative electrode 22 can be increased by an amount comparable to the thickness of the insulating portion 32A, thereby increasing the charge / discharge capacity.

[0113] The negative current collector 25 has essentially the same shape as the positive current collector 24, but has a different strip-shaped portion 34. Figure 3B The strip-shaped portion 34 of the negative current collector 25 is shorter than the strip-shaped portion 32 of the positive current collector 24, and lacks a portion equivalent to the insulating portion 32A. For example... Figure 3B , Figure 15B , Figure 15D As shown, the strip portion 34 has a circular protrusion (protrusion) 37 capable of welding the strip portion 34 to the outer can 11. The flat fan-shaped portion 33 and the rectangular strip portion 34 can be connected by defining two corners 48. Figure 3B , Figure 15B as well as Figure 15D As shown, the two corner portions 48 can be bent separately. The fan-shaped portion 33 includes a curved portion and two straight portions. Figure 3B , Figure 15B as well as Figure 15DAs shown, the lines 49 of the two straight sections can be the same straight line or substantially the same straight line within the manufacturing tolerance and / or measurement tolerance range. In resistance welding, the current is concentrated on the protrusion, causing the protrusion to melt and weld the strip 34 to the bottom of the outer can 11. Similar to the positive current collector 24, the negative current collector 25 includes a hole 36 near the center of the fan-shaped section 33, and the hole 36 is arranged in a manner consistent with the through hole 26 at a position corresponding to the through hole 26. The fan-shaped section 31 of the positive current collector 24 and the fan-shaped section 33 of the negative current collector 25 can have a fan shape, so that a portion of the ends 41, 42 can be covered. The hole 36 is not covered because, during the assembly of the battery 1, the electrolyte can smoothly penetrate into the electrode winding body 20, or the gas generated by the battery under abnormal high temperature conditions or overcharge conditions can be easily released to the outside of the battery 1.

[0114] The positive electrode active material layer 21B comprises one or more positive electrode materials capable of lithium insertion and extraction as positive electrode active materials. However, the positive electrode active material layer 21B may also comprise one or more other materials such as positive electrode agents and positive electrode conductive agents. Examples of positive electrode materials include lithium-containing compounds, and more specifically, lithium-containing composite oxides, lithium-containing phosphate compounds, etc.

[0115] Lithium-containing composite oxides are oxides that contain lithium and one or more other elements (elements other than lithium) as constituent elements, such as layered rock salt crystal structures, spinel crystal structures, etc. Lithium-containing phosphate compounds are phosphate compounds that contain lithium and one or more other elements as constituent elements, such as olivine crystal structures.

[0116] Examples of positive electrode conductive agents include, for example, any one or more synthetic rubbers and polymers. Examples of synthetic rubbers include styrene-butadiene rubber, fluororubber, and ethylene propylene diene monomer (EPDM) rubber. Examples of polymers include polyvinylidene fluoride (PVDF) and polyimide. Examples of positive electrode conductive agents include, for example, any one or more carbon materials. Examples of carbon materials include graphite, carbon black, acetylene black, and Ketjen black. As long as the positive electrode conductive agent is a conductive material, it can be a metallic material, a conductive polymer, etc.

[0117] The surface of the negative electrode foil 22A can be roughened. This is because the adhesion between the negative electrode active material layer 22B and the negative electrode foil 22A is improved through the so-called anchoring effect. In this case, the surface of the negative electrode foil 22A only needs to be roughened in at least the area opposite to the negative electrode active material layer 22B. Examples of roughening methods include forming microparticles using electrolytic treatment. The unevenness of the surface of the negative electrode foil 22A is imparted by electrolytic treatment because microparticles are formed on the surface of the negative electrode foil 22A by electrolysis within an electrolytic cell. Copper foil produced by electrolysis is generally called electrolytic copper foil.

[0118] The negative electrode active material layer 22B may contain one or more negative electrode materials capable of lithium insertion and extraction as negative electrode active materials. However, the negative electrode active material layer 22B may also contain one or more other materials such as negative electrode binders and negative electrode conductive agents.

[0119] Carbon materials can be used as anode materials, for example. This is because the changes in crystal structure during lithium insertion and extraction are very small, thus enabling the stable achievement of high energy density. Furthermore, carbon materials also function as a conductive agent in the anode, thereby improving the conductivity of the anode active material layer 22B.

[0120] Examples of carbon materials include graphitizable carbon, non-graphitizable carbon, and graphite. However, the interplanar spacing of the (002) facets in non-graphitizable carbon can be about 0.37 nm or more within the range of manufacturing tolerances and / or measurement tolerances, while the interplanar spacing of the (002) facets in graphite can be about 0.34 nm or less within the range of manufacturing tolerances and / or measurement tolerances. More specifically, examples of carbon materials include pyrolytic carbon, coke, glassy carbon fibers, sintered organic polymers, activated carbon, and carbon black. Examples of coke include pitch coke, needle coke, and petroleum coke. Sintered organic polymers are obtained by sintering (carbonizing) polymers such as phenolic resins or furan resins at an appropriate temperature. Furthermore, carbon materials can be low-crystallinity carbon that has been heat-treated at a temperature of about 1000°C or lower, or they can be amorphous carbon. Carbon materials can also be in any of the following shapes: fibrous, spherical, granular, or scaly.

[0121] In battery 1, when the open-circuit voltage (i.e., battery voltage) at full charge is approximately 4.25V or higher, compared to when the open-circuit voltage at full charge is approximately 4.20V, the lithium extraction / intercalation per unit mass increases even when using the same positive electrode active material. Therefore, by appropriately adjusting the amount of positive and negative electrode active material used, a high energy density can be obtained.

[0122] The separator 23 is located between the positive electrode 21 and the negative electrode 22, preventing short circuits caused by the current generated from the contact between the positive electrode 21 and the negative electrode 22 while allowing lithium ions to pass through. The separator 23 can be any one or more porous membranes such as synthetic resin or ceramic, or it can be a laminate of two or more porous membranes. Examples of synthetic resins include polytetrafluoroethylene, polypropylene, and polyethylene.

[0123] In particular, the separator 23 may, for example, comprise the aforementioned porous membrane (substrate layer) and a polymer compound layer disposed on one or both sides of the substrate layer. This is because, due to the improved adhesion of the separator 23 to both the positive electrode 21 and the negative electrode 22, warping of the electrode winding 20 is suppressed. This suppresses the decomposition reaction of the electrolyte and also suppresses leakage of the electrolyte impregnated in the substrate layer. Therefore, even with repeated charging and discharging, the resistance value does not easily increase, and the secondary battery does not easily expand.

[0124] The polymer compound layer may contain, for example, a polymer compound such as polyvinylidene fluoride (PVDF). This is because polymer compounds have excellent physical strength and are electrochemically stable. However, the polymer compound may also be a compound other than PVDF. When forming the polymer compound layer, for example, after coating a substrate layer with a solution in which the polymer compound is dissolved in an organic solvent, the substrate layer is dried. Alternatively, the substrate layer may be immersed in the solution and then dried. This polymer compound layer may contain, for example, any one or more insulating particles such as inorganic particles. Examples of inorganic particles include alumina and aluminum nitride.

[0125] Electrolytes contain solvents and electrolyte salts. However, electrolytes may also contain one or more other materials, such as additives.

[0126] The solvent includes one or more non-aqueous solvents such as organic solvents. Electrolytes containing non-aqueous solvents are called non-aqueous electrolytes.

[0127] Examples of non-aqueous solvents include cyclic carbonates, linear carbonates, lactones, linear carboxylic esters, and nitriles (mononitriles). Examples of electrolyte salts include any one or more salts such as lithium salts. However, electrolyte salts may include salts other than lithium salts. Examples of salts other than lithium include salts of light metals other than lithium.

[0128] Examples of lithium salts include lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiCIO4), lithium hexafluoroarsenate (LiAsF6), lithium tetraphenylborate (LiB(C6H5)4), and lithium methanesulfonate (LiCH3SO3), lithium trifluoromethanesulfonate (LiCF3SO3), lithium tetrachloroaluminate (LiAlCl4), dilithium hexafluorosilicate (Li2SF6), lithium chloride (LiCl), and lithium bromide (LiBr).

[0129] One or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium hexafluoroarsenate can be used.

[0130] The content of electrolyte salts is not particularly limited, but can be set to about 0.3 mol / kg to about 3 mol / kg within the range of manufacturing tolerances and / or measurement tolerances relative to the solvent.

[0131] Regarding the manufacturing method of battery 1, refer to... Figures 4A to 4F The following explanation is provided. First, a positive electrode active material layer 21B can be coated on the surface of the strip-shaped positive electrode foil 21A to form a covered portion and an uncovered portion (e.g., a positive electrode foil extension 21C) of the positive electrode 21. Similarly, a negative electrode active material layer 22B can be coated on the surface of the strip-shaped negative electrode foil 22A to form a covered portion and an uncovered portion (e.g., a negative electrode foil extension 22C) of the negative electrode 22. The positive electrode foil extension 21C and the negative electrode foil extension 22C, which are not coated with either the positive or negative electrode active material layer 21B, can be located at one end of the positive electrode 21 in the width direction and one end of the negative electrode 22 in the width direction. Furthermore, slits can be formed in the positive electrode foil extension 21C and the negative electrode foil extension 22C at portions corresponding to the winding start position during winding. The positive electrode 21 and the negative electrode 22 can then undergo processes such as drying. Next, with the positive electrode foil extension 21C of the positive electrode 21 and the negative electrode foil extension 22C of the negative electrode 22 facing opposite directions, the positive electrode 21 and the negative electrode 22 are stacked with the separator 23 in between, and wound into a spiral shape to form a through hole 26 for the central axis to pass through. A cutout is arranged near the central axis, thereby enabling the fabrication of... Figure 4A The electrode winding body 20 shown.

[0132] Next, as Figure 4B As shown, the ends of the thin plate (e.g., 0.5 mm thick) are pressed vertically or substantially vertically onto ends 41 and 42 within manufacturing and / or measurement tolerances, causing ends 41 and 42 to bend locally, thereby enabling the formation of grooves 43. Grooves 43 can be formed using a groove-making tool with a non-sharp tip to avoid damaging the positive electrode foil 21A and the negative electrode foil 22A. Grooves 43 extending toward the central axis can be arranged radially around the through hole 26. Furthermore, Figure 4B The number and arrangement of slots 43 shown are illustrative; the number and arrangement of slots 43 are arbitrary. Next, as... Figure 4C As shown, the same pressure is applied simultaneously from both sides in a direction perpendicular or substantially perpendicular to the ends 41 and 42, causing the positive foil extension 21C of the positive electrode 21 and the negative foil extension 22C of the negative electrode 22 to bend. Afterward, the ends 41 and 42 can be formed into predetermined flat surfaces. At this time, a load can be applied through the surface of a flat plate, etc., to cause the bending of a portion of the positive foil extension 21C in end 41 to overlap and bend towards the through hole 26, and to cause the bending of a portion of the negative foil extension 22C in end 42 to overlap and bend towards the through hole 26. Afterward, the fan-shaped portion 31 of the positive current collector plate 24 is joined to end 41 (e.g., by laser welding), and the fan-shaped portion 33 of the negative current collector plate 25 is joined to end 42 (e.g., by laser welding).

[0133] After that, as Figure 4D As shown, the strip-shaped portions 32 and 34 of the current collectors 24 and 25 can be bent to attach the insulating plates 12 and 13 (or insulating tape) to the positive current collector 24 and the negative current collector 25. Figure 13A , Figure 13B , Figure 13C , Figure 13F as well as Figure 13G As shown, an insulator 53 can be attached to the positive electrode side end of the electrode winding 20, such as... Figure 13A , Figure 13D , Figure 13E , Figure 13H as well as Figure 13I As shown, an insulator 54 is attached to the negative electrode side end of the electrode winding 20. The insulator 53 covers a portion of the side surface of the electrode winding 20 and a portion of the end 41 in such a manner that the rectangular strip 32 of the positive electrode current collector 24 separates from the end 41. The insulator 54 covers a portion of the side surface of the electrode winding 20 and a portion of the end 42 in such a manner that the strip 34 of the negative electrode current collector 25 separates from the end 42. Figure 14A , Figure 14B , Figure 14C , Figure 14F as well as Figure 14G As shown, the insulating plate 12 may include: an outlet for the rectangular strip 32 of the positive current collector 24 to extend from; a large hole 45 aligned with the through hole 26 corresponding to the through hole 26 of the electrode winding body 20; and a small hole 46 disposed around the large hole 45 to allow electrolyte to pass through. Figure 14A , Figure 14D , Figure 14E , Figure 14H as well as Figure 14IAs shown, the insulating plate 13 may include: an outlet for the strip portion 34 of the negative electrode current collector 25 to extend; and a hole corresponding to the through hole 26 of the electrode winding body 20 in a manner that aligns with the through hole 26.

[0134] After installing insulating plates 12 and 13 onto the positive current collector 24 and the negative current collector 25, as follows Figure 4E As shown, the electrode winding body 20 assembled in the above manner can be inserted into the outer can 11, and the bottom of the outer can 11 is welded. After the electrolyte is injected into the outer can 11, as... Figure 4F As shown, it can be sealed by gasket 15 and battery cover 14.

[0135] It should be understood that the above description is merely illustrative of the invention. Those skilled in the art will be able to devise various alternatives or modifications without departing from the invention. Therefore, the invention is intended to encompass all such alternatives, modifications, and variations falling within the scope of the appended claims.

Claims

1. An electrode winding body, comprising a positive electrode, a negative electrode, and a separator between the positive and negative electrodes. The positive electrode includes: Positive electrode foil; The positive electrode active material is located on a portion of the positive electrode foil; as well as A positive electrode foil extension extends from the positive electrode foil, wherein the positive electrode active material is not located on the positive electrode foil extension. The negative electrode includes: Negative electrode foil; The negative electrode active material is located on a portion of the negative electrode foil; and A negative electrode foil extension extends from the negative electrode foil, wherein the negative electrode active material is not located on the negative electrode foil extension. The positive electrode, negative electrode, and diaphragm are wound into a defined helix including through holes, and have a central axis extending through the through holes. The positive electrode foil extension extends from the first end of the electrode winding body. The negative electrode foil extension extends from the second end, which is opposite to the first end of the electrode winding. A portion of the positive electrode foil extension includes a first bend that bends toward a central axis in such a manner that a portion of the positive electrode foil extension overlaps with and defines a first surface. The first bending shape of the first bending portion of the positive electrode foil extension is asymmetrical relative to the central axis. A portion of the negative electrode foil extension includes a second bent portion, which bends toward a central axis in such a manner that a portion of the negative electrode foil extension overlaps with and defines a second surface. The second bending shape of the second bending portion of the negative electrode foil extension is asymmetrical relative to the central axis.

2. The electrode winding body according to claim 1, wherein, A portion of the positive electrode foil extension includes multiple first bends. A portion of the negative electrode foil extension includes multiple second bends, and The number of first bends in the positive electrode foil extension is greater than the number of second bends in the negative electrode foil extension.

3. The electrode winding body according to claim 1 or 2, wherein, A portion of the diaphragm includes a third bend.

4. The electrode winding body according to any one of claims 1 to 3, wherein, A portion of the positive electrode active material includes a fourth bend, and A portion of the negative electrode active material includes the fifth bend.

5. The electrode winding body according to any one of claims 1 to 4, wherein, A portion of the positive electrode foil and / or a portion of the negative electrode foil are folded in such a way that they cover the innermost portion of the diaphragm closest to the through-hole.

6. The electrode winding body according to any one of claims 1 to 5, wherein, The positive electrode foil extension includes a first groove on the first surface, and The negative electrode foil extension includes a second groove on the second surface.

7. The electrode winding body according to claim 6, wherein, The bottom surface of the first groove is curved, and The bottom surface of the second groove is curved.

8. The electrode winding body according to claim 7, wherein, The first curvature of the first groove is less than the second curvature of the second groove.

9. The electrode winding body according to any one of claims 6 to 8, wherein, The second groove is deeper than the first groove.

10. The electrode winding body according to any one of claims 1 to 9, wherein, There are also voids between adjacent first bends in the radial direction of the positive electrode foil extension or between adjacent second bends in the radial direction of the negative electrode foil extension.

11. The electrode winding body according to any one of claims 1 to 10, wherein, The first surface has a glossy appearance and is substantially smooth, and The second surface has a glossy appearance and is substantially smooth.

12. The electrode winding body according to any one of claims 1 to 11, wherein, The first distance between adjacent portions of the positive electrode foil extension in the radial direction decreases as the second distance to the negative electrode active material increases, and The third distance between adjacent portions of the negative electrode foil extension in the radial direction decreases as the fourth distance from the positive electrode active material increases.

13. The electrode winding body according to any one of claims 1 to 11, wherein, The first distance between adjacent portions in the radial direction of the positive electrode foil extension decreases as the second distance to the through hole decreases, and The third distance between adjacent portions in the radial direction of the negative electrode foil extension decreases as the fourth distance to the through hole decreases.

14. The electrode winding body according to any one of claims 1 to 13, wherein, The degree of fit between adjacent portions of the positive electrode foil extension in the radial direction increases as the first distance to the through hole decreases, and The degree of fit between adjacent portions of the negative electrode foil extension in the radial direction increases as the second distance to the through hole decreases.

15. A battery comprising: Outer packaging cans; as well as The electrode winding body according to any one of claims 1 to 14, housed in an outer can.

16. The battery according to claim 15, wherein, The battery also includes: A positive current collector plate, bonded to the first surface, includes a first flat fan-shaped portion and a first rectangular strip-shaped portion; and The negative current collector plate is joined to the second surface and includes a second flat fan-shaped portion and a second rectangular strip-shaped portion.

17. The battery according to claim 16, wherein, After the positive current collector plate and the negative current collector plate are respectively joined to the first surface and the second surface, the first groove does not maintain its cross-sectional shape, while the second groove maintains its cross-sectional shape.

18. The battery according to claim 16 or 17, wherein, The first sector of the positive electrode current collector includes a first curved portion and two first straight portions, the two first straight portions being located on the same straight line; and the second sector of the negative electrode current collector includes a second curved portion and two second straight portions, the two second straight portions being located on the same straight line.

19. The battery according to any one of claims 16 to 18, wherein, The first flat sector and the first rectangular strip of the positive current collector plate are connected at two first curved corners, and The second flat sector and the second rectangular strip of the negative electrode current collector are connected at two second curved corners.

20. The battery according to any one of claims 16 to 19, wherein, The battery also features: A positive electrode insulator, coupled to the positive electrode current collector, includes a large hole aligned with the through hole, and small holes disposed around the large hole; and The negative insulator, which is coupled to the negative current collector, includes a hole aligned with the through hole.

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