Cylindrical battery

Abstract

The cylindrical battery comprises a wound electrode body (14), a bottomed cylindrical outer can (16) for housing the electrode body (14), and a sealing body (17) for sealing the opening of the outer can (16), and includes a plurality of positive electrode leads (20) connected to the positive electrode of the electrode body (14). The cylindrical battery also comprises a pressing member (30) disposed between the electrode body (14) and the sealing body (17), which presses the electrode body (14) through an insulating plate (18). The pressing member (30) is a conductive member that connects the positive electrode leads (20) and the sealing body (17) to electrically connect the positive electrode leads (20) and the sealing body (17).

Description

Technical Field

[0001] This disclosure relates to cylindrical batteries. Background Technology

[0002] Cylindrical batteries generally have the following structure: a spirally wound electrode body with a positive and a negative electrode separated by a separator; a bottomed cylindrical outer can containing the electrode body; and a sealing body that seals the opening of the outer can. Leads extending from the electrode body are connected to the sealing body (see, for example, Patent Document 1). Furthermore, the outer can of the cylindrical battery has a slotted portion formed by inserting an annular groove into its outer circumferential surface, with a portion of its inner circumferential surface protruding radially inward. The slotted portion, for example, supports the sealing body and presses down on the outer circumference of the electrode body, suppressing movement of the electrode body.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: International Publication No. WO2022 / 270432 Summary of the Invention

[0006] As mentioned above, the slotted portion of the outer can helps suppress electrode displacement. However, when the battery is subjected to significant vibration or impact, it is conceivable that the slotted portion alone cannot adequately suppress electrode displacement. In particular, if the diameter of the cylindrical battery increases, electrode displacement is more likely to occur, resulting in a shift in the relative positions of the positive electrode, negative electrode, and separator constituting the electrode (so-called winding offset).

[0007] The cylindrical battery disclosed herein comprises a wound electrode body, a bottomed cylindrical outer can containing the electrode body, and a sealing body that seals the opening of the outer can, and includes leads connected to the electrodes constituting the electrode body. The cylindrical battery further comprises a pressing member disposed between the electrode body and the sealing body, pressing the electrode body through an insulating material. The pressing member is a conductive member connected to the leads and the sealing body, electrically connecting the leads to the sealing body.

[0008] According to the cylindrical battery disclosed herein, displacement of the electrode body within the outer casing and the generation of electrode body winding offset can be suppressed. The structure of the cylindrical battery disclosed herein is suitable, for example, for large cylindrical batteries with a larger diameter. Attached Figure Description

[0009] Figure 1 This is a cross-sectional view of a cylindrical battery as an example of an implementation method.

[0010] Figure 2This is a perspective view of the upper part of a cylindrical battery as an example of an implementation, showing the state before the sealing body is fastened and fixed.

[0011] Figure 3 This is a diagram showing the first modified example of the pressing member.

[0012] Figure 4 This is a diagram showing the second variation of the pressing member.

[0013] Figure 5 This is a diagram showing the third variation of the pressing member. Detailed Implementation

[0014] Hereinafter, an example of an embodiment of the cylindrical battery according to the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, structures formed by selectively combining the constituent elements of the various embodiments and modifications described below are included within the scope of this disclosure.

[0015] Figure 1 This is a cross-sectional view of a cylindrical battery 10 as an example of an implementation. Figure 1 As shown, the cylindrical battery 10 includes: a wound electrode body 14, an electrolyte, a bottomed cylindrical outer casing 16 containing the electrode body 14 and the electrolyte, and a sealing body 17 that seals the opening of the outer casing 16. The electrode body 14 has a positive electrode 11, a negative electrode 12, and a separator 13, and has a wound structure in which the positive electrode 11 and the negative electrode 12 are wound into a spiral shape with the separator 13 in between. Hereinafter, for ease of explanation, the sealing body 17 side of the battery is described as the upper side, and the bottom side of the outer casing 16 is described as the lower side.

[0016] The positive electrode 11, negative electrode 12, and separator 13 constituting the electrode body 14 are all strip-shaped elongated bodies, which are alternately stacked in the radial direction of the electrode body 14 by being wound into a spiral shape. To prevent lithium deposition, the negative electrode 12 is formed to be one size larger than the positive electrode 11. That is, the negative electrode 12 is formed to be longer than the positive electrode 11 in both its long and wide directions. The separator 13 is formed to be at least one size larger than the positive electrode 11; for example, two separators are arranged sandwiching the positive electrode 11. The electrode body 14 has a positive electrode lead 20 connected to the positive electrode 11 by welding or the like, and a negative electrode lead 21 connected to the negative electrode 12 by welding or the like.

[0017] Details will be described later, but the cylindrical battery 10 includes multiple positive leads 20. The cylindrical battery 10 also includes a pressing member 30 disposed between the electrode body 14 and the sealing body 17, pressing the electrode body 14 through an insulating material. The pressing member 30 is a conductive member connecting the positive leads 20 and the sealing body 17, electrically connecting the positive leads 20 and the sealing body 17. That is, the pressing member 30 functions as a positive current collector member, forming part of the current path of the positive electrode 11. Furthermore, a negative lead can also be connected to the pressing member, making the pressing member a negative current collector member.

[0018] The positive electrode 11 has a positive electrode core and a positive electrode binder layer disposed on the positive electrode core. For the positive electrode core, a foil of a metal stable within the potential range of the positive electrode 11, such as aluminum, aluminum alloy, stainless steel, or titanium, or a film of such metal disposed on the surface, can be used. The positive electrode binder layer comprises a positive electrode active material, a conductive agent, and a binder, and is preferably disposed on both sides of the positive electrode core excluding the portion connected to the positive electrode lead 20. For the positive electrode active material, a lithium transition metal composite oxide containing transition metal elements such as Ni, Co, and Mn is used.

[0019] The negative electrode 12 has a negative electrode core and a negative electrode binder layer disposed on the negative electrode core. For the negative electrode core, a foil of a metal stable within the potential range of the negative electrode 12, such as copper, copper alloy, stainless steel, nickel, or nickel alloy, or a film of such metal disposed on the surface, can be used. The negative electrode binder layer contains a negative electrode active material and a binder, and is preferably disposed on both sides of the negative electrode core excluding the portion connected to the negative electrode lead 21. For the negative electrode active material, a carbon material that reversibly absorbs and releases lithium ions is generally used. Elements alloyed with Li, such as Si and Sn, or materials containing such elements can also be used.

[0020] For the spacer 13, a porous sheet material with ion permeability and insulation is used. Specific examples of porous sheets include microporous films, woven fabrics, and nonwoven fabrics. Suitable materials for the spacer 13 include polyethylene, polyolefins such as polypropylene, and cellulose. The spacer 13 can be a single-layer or multi-layer structure. For example, the spacer 13 can also have a multi-layer structure comprising a thermoplastic resin layer such as a polyolefin and a cellulose fiber layer, a two-layer structure of polyethylene (PE) / polypropylene (PP), or a three-layer structure of PE / PP / PE.

[0021] The electrolyte can be an aqueous electrolyte, but in this embodiment, a non-aqueous electrolyte is used. The non-aqueous electrolyte has lithium-ion conductivity. The non-aqueous electrolyte can be a liquid electrolyte (electrolyte) or a solid electrolyte.

[0022] Liquid electrolytes (electrolytes) comprise a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. Examples of non-aqueous solvents include esters, ethers, nitriles, amides, and mixtures of two or more of these. Examples of non-aqueous solvents include ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and mixtures thereof. Non-aqueous solvents may also contain halogen-substituted derivatives (e.g., fluoroethylene carbonate) obtained by substituting at least a portion of the hydrogen atoms of these solvents with halogen atoms such as fluorine. Examples of electrolyte salts include lithium salts such as LiPF6.

[0023] As solid electrolytes, examples include solid or gel-like polymer electrolytes and inorganic solid electrolytes. As inorganic solid electrolytes, materials known in all-solid-state lithium-ion secondary batteries (e.g., oxide-based solid electrolytes, sulfide-based solid electrolytes, halogen-based solid electrolytes, etc.) can be used. Polymer electrolytes, for example, comprise lithium salts and matrix polymers or non-aqueous solvents, or lithium salts and matrix polymers. As matrix polymers, examples include polymer materials that absorb non-aqueous solvents and undergo gelation. Examples of polymer materials include fluoropolymers, acrylic resins, and polyether resins.

[0024] Insulating plates 18 and 19 are respectively disposed above and below the electrode body 14. Figure 1 In the example shown, the positive lead 20 extends towards the sealing body 17 through the through hole in the insulating plate 18, and the negative lead 21 extends towards the bottom of the outer can 16 through the outer side of the insulating plate 19. A pressing member 30, to which multiple positive leads 20 are connected, is connected to the lower surface of the internal terminal plate 23 of the sealing body 17 by welding or the like, and the top plate, i.e., the cover 27, of the sealing body 17, which is electrically connected to the internal terminal plate 23, becomes the positive terminal. The negative lead 21 is connected to the inner bottom surface of the outer can 16 by welding or the like, and the outer can 16 becomes the negative terminal. The outer can 16 and the sealing body 17 are connected, for example, to external circuits such as other batteries or chargers that constitute the battery module.

[0025] The outer can 16 is a bottomed cylindrical metal container with an opening on one side in the axial direction. The opening of the outer can 16 is sealed by a sealing body 17. A gasket 28 is provided between the outer can 16 and the sealing body 17 to ensure the airtightness of the battery interior. A slotted portion 22 is formed in the outer can 16, extending inward from a portion of its side surface, to support the sealing body 17. The slotted portion 22 is preferably formed in a ring shape along the circumference of the outer can 16, supporting the sealing body 17 through its upper surface. The sealing body 17 is fixed to the upper part of the outer can 16 by the slotted portion 22 and the opening end of the outer can 16 that is fastened relative to the sealing body 17.

[0026] The sealing body 17 has a structure in which an internal terminal plate 23, a lower valve body 24, an insulating member 25, an upper valve body 26, and a cover 27 are stacked sequentially from the electrode body 14 side. Each component constituting the sealing body 17 has, for example, a circular or annular shape, and all components except the insulating member 25 are electrically connected to each other. The lower valve body 24 and the upper valve body 26 are connected at their respective central portions, and the insulating member 25 is located between the peripheral portions of each valve body. When the internal pressure of the battery rises due to abnormal heating, the lower valve body 24 presses the upper valve body 26 towards the cover 27, causing it to break, thereby cutting off the current path between the lower valve body 24 and the upper valve body 26. When the internal pressure rises further, the upper valve body 26 breaks, and gas is discharged from the opening of the cover 27.

[0027] The following is further reference. Figure 2 The positive lead 20 and the pressing member 30 will be described in detail below. Figure 2 This is a perspective view of the upper part of the cylindrical battery 10, showing the state before the opening of the outer can 16 is sealed by the sealing body 17.

[0028] like Figure 1 as well as Figure 2 As shown, the electrode body 14 includes a plurality of positive electrode leads 20 connected to the positive electrode 11. The plurality of positive electrode leads 20 extend from the upper end of the electrode group 14a constituting the electrode body 14 toward the sealing body 17 and are connected to the pressing member 30 disposed on the insulating plate 18. Furthermore, the term "electrode group 14a" refers to a wound body composed of the positive electrode 11, the negative electrode 12, and the insulating member 13, with a hollow portion 29 formed in the core of the electrode group 14a. The hollow portion 29 is a space extending along the axial direction of the electrode group 14a. The pressing member 30 is a conductive member connected to the sealing body 17, and the positive electrode leads 20 are electrically connected to the sealing body 17 via the pressing member 30.

[0029] The positive electrode lead 20 is a short, strip-shaped conductive component, for example, made of a metal with aluminum as the main component. The preferred material for the positive electrode lead 20 is an aluminum alloy. An aluminum alloy is an alloy with one or more other metallic elements added, such as copper, manganese, silicon, magnesium, zinc, and nickel. By adjusting the type and amount of added elements, the material's resistance, hardness, and other properties can be varied.

[0030] The width and thickness of the positive electrode lead 20 vary depending on the size and capacity of the battery, but an example of the width of the positive electrode lead 20 is 2mm or more and 15mm or less, or 3mm or more and 10mm or less. An example of the thickness of the positive electrode lead 20 is 0.03mm or more and 0.15mm or less, or 0.05mm or more and 0.10mm or less. Multiple positive electrode leads 20 can also have different widths and thicknesses, but... Figure 2 In the example shown, all the positive leads 20 have substantially the same width and thickness.

[0031] Positive lead 20 is soldered to the core of positive electrode 11. In positive electrode 11, multiple core exposure portions are separately provided along the length of positive electrode 11, where no positive electrode binder layer exists on the core and the surface of the core is exposed. Positive lead 20 is connected one by one to each exposure portion by soldering or the like. Positive lead 20 is generally only bonded to one side of the positive electrode core, but core exposure portions are provided on both sides of positive electrode 11. The core exposure portions are formed, for example, of substantially the same size, so that they overlap in the thickness direction of positive electrode 11. The soldering position of the positive lead 20 in each exposure portion is not particularly limited; the positive lead 20 is positioned within the range of the core exposure portion so as not to overlap with the positive electrode binder layer.

[0032] exist Figure 2 In the illustrated configuration, three positive electrode leads 20 are provided, thus forming three exposed core portions at three points along the length of the positive electrode 11. The spacing between these exposed portions can be fixed or varied, but the layout of the positive electrode leads 20 is appropriately set according to the battery performance, such as the capacity and output characteristics of the cylindrical battery 10. Therefore, the spacing between the exposed core portions is determined based on this layout. Furthermore, the number of positive electrode leads 20 can be one, but in large batteries, multiple leads are preferred, for example, two or more and up to 15.

[0033] The pressing member 30 is disposed between the electrode body 14 and the sealing body 17, pressing the electrode body 14 through an insulating material to suppress movement of the electrode body 14 within the outer packaging can 16 and to prevent the electrode body 14 from shifting. Since the outer periphery of the electrode body 14 can be pressed by the slotted portion 22, the pressing member 30 is preferably positioned far from the slotted portion 22, overlapping in the axial direction with the radially inner portion of the electrode body 14. In this embodiment, since the outer packaging can 16 with the slotted portion 22 functions as the negative terminal, the pressing member 30 is configured not to contact the slotted portion 22.

[0034] The pressing member 30 is a conductive component welded with multiple positive leads 20 and welded to the sealing body 17, functioning as a positive current collector. The material of the pressing member 30 is not particularly limited, but it can be made of a metal primarily composed of aluminum, for example, similar to the positive leads 20. A suitable example of the material for the pressing member 30 is an aluminum alloy. The pressing member 30 includes a welding portion 32 to the sealing body 17 and a welding portion 31 to the positive leads 20.

[0035] The pressing member 30 is disposed on the electrode body 14 with the insulating plate 18 in between. While the pressing member 30 is disposed on the insulating plate 18, it can also be fixed to the insulating plate 18. Furthermore, the insulating material between the electrode body 14 and the pressing member 30 is not limited to the insulating plate 18; for example, it can be any insulating material constituting either the electrode body 14 or the pressing member 30. Examples of insulating materials other than the insulating plate 18 include the spacer 13 constituting the electrode body 14 and an insulating layer disposed on the surface of the pressing member 30 opposite to the electrode body 14.

[0036] The pressing member 30 is disposed on the core (central axis) of the electrode body 14. In this embodiment, the electrode body 14 has a hollow portion 29 formed in the core, and the pressing member 30 is disposed on the hollow portion 29. That is, the pressing member 30 is disposed at a position where it overlaps with the hollow portion 29 in the axial direction of the electrode body 14. The pressing member 30 has a width and length larger than the diameter of the hollow portion 29, and is configured, for example, to cover the entire hollow portion 29 and the radially inner portion of the electrode body 14. By disposing the pressing member 30 on the core of the electrode body 14, displacement of the electrode body 14 can be more effectively suppressed.

[0037] The pressing member 30 has a through hole 34 in the portion overlapping with the hollow portion 29. The hollow portion 29 of the electrode body 14 becomes a venting path when gas is generated due to an anomaly in the battery. Therefore, it is preferable to form a through hole 34 in the pressing member 30 to ensure a venting path. That is, the through hole 34 functions as a vent. The pressing member 30 is configured such that at least a portion of the through hole 34 overlaps with the hollow portion 29 in the axial direction of the electrode body 14. Figure 2 In the example shown, the positive lead 20 is soldered around the through hole 34 of the pressing member 30 so as not to cover the through hole 34.

[0038] In the pressing member 30, a plurality of welded portions 31 are formed surrounding the through hole 34. The positive electrode lead 20 is welded to the first surface (upper surface) of the pressing member 30 facing the sealing body 17, or to the second surface (lower surface) of the pressing member 30 facing the electrode body 14, or to both the first and second surfaces. Figure 2 In the example shown, all the positive leads 20 are soldered to the upper surface of the pressing member 30. In this case, a good weld 31 can be easily formed, and the reliability of the weld 31 is improved. The weld 31 can also be formed on the hollow portion 29 of the electrode body 14. In this case, the weld 31 can be formed by inserting a jig used for welding into the hollow portion 29.

[0039] The through hole 34 is formed by the pressing member 30 penetrating through the electrode body 14 in the axial direction. Figure 2In the example shown, the shape is perfectly circular when viewed from above. Additionally, a through-hole is also formed in the insulating plate 18 at a position overlapping with the through-hole 34. When viewed from above with the electrode body 14 and the pressing member 30, the through-hole 34 is larger than the hollow portion 29, allowing the pressing member 30 to be positioned on the electrode body 14 such that the entire hollow portion 29 is exposed through the through-hole 34. The pressing member 30 is, for example, configured such that the center of the through-hole 34 overlaps with the central axis of the electrode body 14.

[0040] The pressing member 30 is a plate-shaped member with a larger cross-sectional area in the width direction compared to the positive electrode lead 20. It has a bent portion 33 in the middle of its length direction and elastically deforms in the axial direction of the electrode body 14. Details will be described later, but the pressing member 30 is positioned between the electrode body 14 and the sealing body 17 in a bent and compressed state with the bent portion 33, and functions as a spring that presses the electrode body 14 through the insulating plate 18. The bent portion 33 is formed by bending the metal plate constituting the pressing member 30. In addition, the bent portion 33 is formed parallel to the width direction of the pressing member 30. Furthermore, a half-cut line, a slit, etc., may also be formed in the bent portion 33. The bent portion 33 is formed in at least one location, but multiple bent portions may also be formed in the length direction of the pressing member 30.

[0041] The pressing member 30 is preferably wider and thicker than the positive electrode lead 20. On the other hand, the length of the pressing member 30 is not particularly limited and may be shorter than the positive electrode lead 20. The pressing member 30 is, for example, a metal plate with a substantially fixed width and thickness throughout its entire length. The dimensions of the pressing member 30 can be appropriately varied depending on the size of the cylindrical battery 10, but the width of the pressing member 30 is, for example, 10 mm or more and 30 mm or less, or 15 mm or more and 25 mm or less. The thickness of the pressing member 30 is, for example, 0.1 mm or more and 1.0 mm or less, or 0.2 mm or more and 0.5 mm or less.

[0042] The width of the pressing member 30 is greater than its thickness. The ratio of the width to the thickness of the pressing member 30 is preferably 30 times or more and 100 times or less, more preferably 40 times or more and 90 times or less, and particularly preferably 50 times or more and 80 times or less. In this case, the good spring characteristics of the pressing member 30 can be effectively utilized. Furthermore, even if at least one of the thickness and width of the pressing member 30 is not fixed, it is acceptable as long as the ratio of the average width to the average thickness, or the ratio of the maximum width to the maximum thickness, is within this range.

[0043] The cross-sectional area in the width direction of the pressing member 30 is larger than that in the width direction of the positive electrode lead 20, preferably 5 times or more but less than 100 times. More preferably, it is 10 times or more but less than 50 times, and particularly preferably 15 times or more but less than 30 times. In this case, adverse conditions such as contact between the outer can 16 and the pressing member 30 and reduction in energy density can be suppressed, while the good spring characteristics of the pressing member 30 can be utilized efficiently. When the cross-sectional area in the width direction of at least one of the positive electrode lead 20 and the pressing member 30 is not fixed, it is acceptable as long as the ratio of the average value or the ratio of the maximum value of the cross-sectional area in the width direction of each member is within this range. The pressing member 30 preferably increases its cross-sectional area in the width direction by further increasing both its thickness and width relative to the positive electrode lead 20.

[0044] The thickness of the pressing member 30 is, for example, 1.5 times or more and 15 times or less, preferably 2 times or more and 10 times or less, the thickness of the positive lead 20. When at least one of the thicknesses of the positive lead 20 and the pressing member 30 is not fixed, it is acceptable as long as the ratio of the average thickness of each member to its maximum thickness is within this range (the same applies to the width). Furthermore, the width of the pressing member 30 is, for example, 1.5 times or more and 10 times or less, preferably 2 times or more and 6 times the width of the positive lead 20.

[0045] The maximum width of the pressing member 30 is preferably 30% to 90% of the minimum inner diameter of the outer can 16, more preferably 35% to 80%, and particularly preferably 40% to 70%. In this embodiment, the inner diameter of the outer can 16 is minimized in the portion where the slotted portion 22 is formed. As long as the ratio of the maximum width of the pressing member 30 to the minimum inner diameter of the outer can 16 is within this range, adverse conditions such as contact between the outer can 16 and the pressing member 30 and reduction in energy density can be suppressed, while the good spring characteristics of the pressing member 30 can be utilized efficiently. In addition, the soldering of the positive lead 20 becomes easier.

[0046] The portion of the pressing member 30 having the welded portion 31 to the positive lead 20 (hereinafter referred to as "the first region") is arranged on the insulating plate 18 along the radial direction of the electrode body 14. The portion having the welded portion 32 to the sealing body 17 (hereinafter referred to as "the second region") is arranged along the lower surface of the sealing body 17. In this embodiment, the bend 33 forms the boundary between the first region and the second region. The bend 33 is positioned further outward in the radial direction than the longitudinal end of the pressing member 30 present in the first region, close to the slotted portion 22.

[0047] The width of the pressing member 30 can also vary along its length. To increase the width of the pressing member 30 while preventing contact with the outer can 16, the width of the pressing member 30 can be varied, making the width of the portion where the bend 33 is formed smaller than the lengthwise end. That is, the width of the pressing member 30 can also be smaller in the portion where the bend 33 is formed than the lengthwise end on the electrode body 14 side. The width of the first region of the pressing member 30 can gradually narrow from the lengthwise end toward the bend 33, or it can narrow in stages at more than one location. The width of the bend 33 of the pressing member 30 can be, for example, less than 90% of the width of the lengthwise end, or it can be more than 30% and less than 80%, or more than 50% and less than 70%. The width of the second region of the pressing member 30 can be substantially the same as the width of the bend 33 throughout its entire length, or it can be wider than the bend 33.

[0048] The pressing member 30 is bent into an L-shape at the bend 33, and has an L-shape when no external force is applied. The pressing member 30 is fastened to the opening edge of the outer can 16 by the sealing body 17, and is positioned between the electrode body 14 and the sealing body 17 in a state where the first region and the second region are opposite each other and compressed in the axial direction of the electrode body 14. In this case, the compressed pressing member 30 functions as a spring that presses the electrode body 14 through the insulating plate 18 in order to return to its original L-shape, and can apply a force to push the electrode body 14 from above by the pressing member 30. The first region and the second region of the pressing member 30 are arranged substantially parallel, and can be opposite each other with a small gap, and can also clamp the positive lead 20 welded to the upper surface of the first region.

[0049] The following is for reference Figures 3-5 Another example of the embodiment will be described. Hereinafter, the same reference numerals will be used for structures that are the same as those in the embodiments described above, and repeated descriptions will be omitted.

[0050] Figure 3 The illustrated pressing member 30x has a protrusion 35 protruding towards the center of a through hole 34x. A positive electrode lead 20 is welded to the upper surface of the protrusion 35. Similar to the pressing member 30, the pressing member 30x is configured such that the through hole 34x overlaps with the hollow portion 29 in the axial direction of the electrode body 14. The pressing member 30x ensures the welding position of the lead and forms a venting path in case of battery malfunction. The through hole 34x is formed, for example, in a roughly C-shaped form when viewed from above. Furthermore, the shape of the through hole is not limited to a perfect circle or a C-shape; for example, it can also be polygonal, cross-shaped, semi-circular, etc.

[0051] Figure 4The illustrated electrode body 14y differs from the electrode body 14 in that the six positive electrode leads 20 are arranged in pairs and overlapped with each other. Furthermore, the pressing member 30y does not have a through hole 34, and the six positive electrode leads 20 are welded to the upper surface of the pressing member 30y with their tips close to each other. The welded portion 31y is formed, for example, at a position where it overlaps with the hollow portion 29 in the axial direction of the electrode body 14. The two positive electrode leads 20 can also be connected to the front and back of a positive electrode core, but as... Figure 4 As shown, preferably, two positive electrode leads 20 extend from the radial direction of the electrode body 14y and are arranged side by side in the radial direction.

[0052] Figure 5 The illustrated method is similar to the above-described embodiment in that it includes a pressing member 30z disposed between the electrode body 14 and the sealing body 17z, separated by an insulating material, i.e., an insulating plate 18, which presses against the electrode body 14. The pressing member 30z is a conductive member that connects the positive electrode lead 20 and the sealing body 17z, electrically connecting the positive electrode lead 20 and the sealing body 17z. On the other hand, the pressing member 30z differs from pressing members 30, 30x, and 30y in that it is a flat, plate-shaped or block-shaped member without bending portions and does not function as a spring that elastically deforms in the axial direction of the electrode body 14. In addition, the positive electrode lead 20 is only soldered to the lower surface of the pressing member 30z.

[0053] The pressing member 30z is not a member that applies force to the electrode body 14, but it is pushed from above by the sealing body 17z. This force presses the electrode body 14 through the insulating plate 18, suppressing displacement and winding deviation of the electrode body 14. The sealing body 17z is fastened to the opening edge of the outer can 16 and pushes the pressing member 30z from above. For example, a laser can be irradiated from the upper surface of the sealing body 17z to form a weld between the sealing body 17z and the pressing member 30z. Figure 5 In the example shown, a through hole 34z is formed in the portion of the pressing member 30z that overlaps with the hollow portion 29 of the electrode body 14.

[0054] As described above, with respect to the cylindrical battery having the above structure, the pressing member presses the radially inner portion of the electrode body 14 from above, thus effectively suppressing displacement of the electrode body 14 within the outer casing 16 and preventing winding offset of the electrode body 14. The outer periphery of the electrode body 14 is pressed by the slotted portion 22, and the radially inner portion near the core is pressed by the pressing member. This structure is particularly suitable for large cylindrical batteries with a large diameter of the electrode body 14.

[0055] Like the pressing member 30, when the bent metal plate is arranged in a compressed state between the electrode body 14 and the sealing body 17, the pressing member 30 functions as a spring that elastically deforms in the axial direction of the electrode body 14, and can impart a force to push the electrode body 14 from above. In this case, the displacement of the electrode body 14 can be effectively suppressed, and the pressing member 30 can be made thin-walled and lightweight. In addition, the assembly and size design of the battery are also easy.

[0056] Furthermore, the above embodiments can be appropriately modified without prejudice to the purpose of this disclosure, and can also be configured to selectively combine the constituent elements of the above multiple embodiments. For example, in Figure 2 The illustrated methods can also be combined with Figure 4 Similarly, in the illustrated manner, the number of positive leads 20 is set to 6. Additionally, multiple pressing members can be arranged between the electrode body and the sealing body.

[0057] This disclosure is further illustrated by the following embodiments.

[0058] Structure 1:

[0059] A cylindrical battery includes a wound electrode body, a bottomed cylindrical outer can containing the electrode body, and a sealing body that seals the opening of the outer can, and includes a lead wire connected to the electrode body. The cylindrical battery further includes a pressing member disposed between the electrode body and the sealing body, which presses the electrode body through an insulating material. The pressing member is a conductive member connected to the lead wire and the sealing body, and electrically connects the lead wire to the sealing body.

[0060] Structure 2:

[0061] In the cylindrical battery described in structure 1, the pressing member is a plate-shaped member with a larger cross-sectional area in the width direction compared to the lead wire, has a curved portion in the middle of the length direction, and elastically deforms in the axial direction of the electrode body.

[0062] Structure 3:

[0063] In the cylindrical battery described in structure 1 or 2, the cross-sectional area of ​​the pressing member in the width direction is more than 5 times and less than 100 times the cross-sectional area of ​​the lead wire in the width direction.

[0064] Structure 4:

[0065] In any of the cylindrical batteries described in structures 1 to 3, the maximum width of the pressing member is more than 30% and less than 90% of the minimum inner diameter of the outer can.

[0066] Structure 5:

[0067] In any of the cylindrical battery structures 1 to 4, the ratio of the width of the pressing member to its thickness is more than 50 times and less than 100 times.

[0068] Structure 6:

[0069] In the cylindrical battery described in structure 2, the width of the pressing member is smaller at the portion where the curved portion is formed than at one end in the length direction of the electrode body.

[0070] Structure 7:

[0071] In the cylindrical battery described in any one of structures 1 to 6, the electrode body has a hollow portion formed in the winding core, the pressing member is disposed on the hollow portion, and has a through hole in the portion overlapping the hollow portion.

[0072] Structure 8:

[0073] In any of the cylindrical battery structures 1 to 7, the lead wire is welded to a first surface of the pressing member in the direction toward the sealing body, or to a second surface of the pressing member in the direction toward the electrode body, or to both the first surface and the second surface.

[0074] -Explanation of Figure Markers-

[0075] 10 Cylindrical battery, 11 Positive electrode, 12 Negative electrode, 13 Separator, 14 Electrode body, 14a Electrode group, 16 Outer can, 17 Sealing body, 18, 19 Insulating plate, 20 Positive lead, 21 Negative lead, 22 Slotted part, 23 Internal terminal plate, 24 Lower valve body, 25 Insulating component, 26 Upper valve body, 27 Cover, 28 Gasket, 29 Hollow part, 30 Pressing component, 31, 32 Welded part, 33 Bending part, 34 Through hole.

Claims

1. A cylindrical battery comprising a wound electrode body, a bottomed cylindrical outer can for housing the electrode body, and a sealing body for sealing the opening of the outer can, and including leads connected to the electrodes constituting the electrode body. The cylindrical battery further comprises: a pressing member disposed between the electrode body and the sealing body, which presses the electrode body through an insulating material. The pressing component is a conductive component that connects the lead wire and the sealing body, electrically connecting the lead wire to the sealing body.

2. The cylindrical battery according to claim 1, wherein, The pressing member is a plate-shaped member with a larger cross-sectional area in the width direction compared to the lead wire, and has a curved portion in the middle of the length direction, which can elastically deform in the axial direction of the electrode body.

3. The cylindrical battery according to claim 2, wherein, The cross-sectional area of ​​the pressing member in the width direction is more than 5 times and less than 100 times the cross-sectional area of ​​the lead wire in the width direction.

4. The cylindrical battery according to claim 2, wherein, The maximum width of the pressing member is more than 30% and less than 90% of the minimum inner diameter of the outer can.

5. The cylindrical battery according to claim 2, wherein, The width of the pressing member is more than 30 times and less than 100 times its thickness.

6. The cylindrical battery according to claim 2, wherein, The width of the pressing member is smaller than that of one end of the electrode body in the longitudinal direction at the portion where the curved portion is formed.

7. The cylindrical battery according to claim 1 or 2, wherein, The electrode body has a hollow portion formed in the winding core. The pressing member is disposed on the hollow portion and has a through hole in the portion overlapping the hollow portion.

8. The cylindrical battery according to any one of claims 1 to 7, wherein, The lead wire is welded to a first surface of the pressing member facing the sealing body, or to a second surface of the pressing member facing the electrode body, or to both the first and second surfaces.

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