Non-aqueous electrolyte secondary battery

Abstract

This non-aqueous electrolyte secondary battery comprises an electrode body in which a positive electrode and a negative electrode (12) are wound with a separator interposed therebetween. The positive electrode in an unwound state has, at a plurality of positions in the longitudinal direction, positive electrode uncoated sections on a part of the width direction where a positive electrode mixture layer is not formed. An inner peripheral region (70), which does not face the positive electrode, of the negative electrode in an unwound state includes: a first region (A) that overlaps the positive electrode uncoated sections in the width direction (Y2), the first region (A) having, in at least a portion in the longitudinal direction (X2), a negative electrode double-sided coated section (42a) where a negative electrode mixture layer (42) is formed on opposite sides; and a second region (B) that does not overlap the positive electrode uncoated sections in the width direction, the second region (B) having a negative electrode uncoated section (41b) positioned at one side of the negative electrode double-sided coated portion of the first region in the width direction, located adjacent to the negative electrode mixture layer in the longitudinal direction, and having at least one surface where the negative electrode mixture layer is not formed.

Description

Non-aqueous electrolyte secondary battery

[0001] The present disclosure relates to a non-aqueous electrolyte secondary battery.

[0002] Conventionally, a non-aqueous electrolyte secondary battery including an electrode body in which a positive electrode and a negative electrode are wound with a separator interposed therebetween, and an outer can containing the electrode body and an electrolyte has been known. In recent years, there has been a demand for higher input / output of secondary batteries used in electric vehicles and the like. For this purpose, in a non-aqueous electrolyte secondary battery, as in the configuration described in Patent Document 1, by joining four current collector leads (current collector tabs) to four core body exposed surfaces (positive electrode non-coated portions) where the positive electrode mixture is peeled off, it is considered possible to improve battery characteristics.

[0003] Japanese Patent Application Laid-Open No. 2000-243376

[0004] By the way, in the negative electrode of the electrode body of a non-aqueous electrolyte secondary battery, the portion facing the positive electrode non-coated portion does not expand during charge and discharge. For this reason, in the electrode body, a gap is likely to occur inside at a portion that coincides with the axial direction corresponding to the positive electrode non-coated portion in the positive electrode width direction. An increase in the gap inside the electrode body causes Li to deposit on the negative electrode, which is not desirable.

[0005] On the other hand, in order to reduce the above gap, it is conceivable to increase the winding direction length of the inner peripheral side region of the negative electrode that does not face the positive electrode and provide a mixture layer on both surfaces of the inner peripheral side region. On the other hand, in the electrode body, the above gap is unlikely to occur in a portion different from the positive electrode non-coated portion in the axial direction. For this reason, in this portion, the tightening force by the inner peripheral side region provided with the mixture layer may become excessive. For this reason, deformation is likely to occur in the inner peripheral side portion of the negative electrode.

[0006] In addition, an unpainted negative electrode portion may be formed at one end in the width direction of the negative electrode, extending over its entire length, and this unpainted negative electrode portion may be joined to a current collector plate attached to the inner surface of the bottom of the outer casing. In this case, during charging and discharging of the secondary battery, a difference in clamping force occurs in the axial direction of the electrode body, which may result in parts of the electrode body where internal gaps are likely to occur and parts where the clamping force is excessive. In this case, for example, in the positive electrode, unpainted positive electrode portions may be formed at multiple positions as described above, or an unpainted positive electrode portion may be formed over its entire width in a part of the longitudinal direction of the positive electrode, and a current collector tab may be joined to the unpainted positive electrode portion.

[0007] Furthermore, in some cases, an uncoated portion of the negative electrode is not formed at one end in the width direction, but rather an uncoated portion is formed in a part of the negative electrode in the longitudinal direction, extending over the entire width direction, and the current collector tab joined to the uncoated portion of the negative electrode is joined to the inner surface of the bottom of the outer casing. In this case as well, during charging and discharging of the secondary battery, a difference in clamping force occurs in the axial direction of the electrode body, which can lead to areas in the electrode body where internal gaps are likely to occur and areas where the clamping force is excessive. In areas where the clamping force is excessive, deformation of the inner circumference of the negative electrode is likely to occur.

[0008] The purpose of this disclosure is to suppress the occurrence of internal gaps in the electrode body and to suppress deformation of the inner circumferential portion of the negative electrode in a non-aqueous electrolyte secondary battery.

[0009] The first non-aqueous electrolyte secondary battery according to this disclosure comprises an electrode body in which a positive electrode having a positive electrode mixture layer formed on both sides of a strip-shaped positive electrode core and a negative electrode having a negative electrode mixture layer formed on both sides of a strip-shaped negative electrode core are wound together via a separator, and a cylindrical outer casing for housing the electrode body, wherein in the expanded state of the positive electrode, at multiple positions in the longitudinal direction, a portion in the width direction has an uncoated positive electrode portion where the positive electrode mixture layer is not formed on the positive electrode core, and a current collecting tab is joined to each of the multiple uncoated positive electrode portions, and in the expanded state of the negative electrode, The non-aqueous electrolyte secondary battery includes: a first region in the width direction that overlaps with the uncoated portion of the positive electrode, and having a negative electrode double-sided coated portion in at least a part of its longitudinal direction, on both sides of which a negative electrode mixture layer is formed; and a second region in the width direction that differs from the uncoated portion of the positive electrode, and is located on one side in the width direction of the negative electrode double-sided coated portion in the first region, is longitudinally adjacent to the negative electrode mixture layer, and has a negative electrode uncoated portion on at least one side on which the negative electrode mixture layer is not formed.

[0010] The second non-aqueous electrolyte secondary battery according to this disclosure comprises an electrode body in which a positive electrode having a positive electrode mixture layer formed on both sides of a strip-shaped positive electrode core and a negative electrode having a negative electrode mixture layer formed on both sides of a strip-shaped negative electrode core are wound via a separator, and a cylindrical outer casing for housing the electrode body, wherein at multiple positions in the longitudinal direction of the deployed positive electrode, a portion in the width direction has an uncoated positive electrode portion in which the positive electrode mixture layer is not formed on the positive electrode core, and a current collector tab is joined to each of the multiple uncoated positive electrode portions, or, at a portion in the longitudinal direction of the deployed positive electrode, an uncoated positive electrode portion has a positive electrode mixture layer not formed on the positive electrode core over the entire width direction, and a current collector tab is joined to the uncoated positive electrode portion, and in the deployed negative electrode, the width direction This is a non-aqueous electrolyte secondary battery in which one end of the negative electrode has a first uncoated negative electrode portion over its entire longitudinal direction in which a negative electrode mixture layer is not formed, and the first uncoated negative electrode portion is joined to a current collector plate joined to the inner surface of the bottom of the outer casing, and in the deployed state of the negative electrode, the inner circumferential region that does not face the positive electrode has a negative electrode double-sided coated portion in the region including the end opposite to the current collector plate in the width direction in which a negative electrode mixture layer is formed on both sides, and in the inner circumferential region, on the same side as the current collector plate in the width direction in which a second uncoated negative electrode portion is connected to the first uncoated negative electrode portion and has a negative electrode mixture layer not formed on at least one side, and the length of the second uncoated negative electrode portion in the longitudinal direction of the negative electrode decreases from the current collector plate side to the side opposite the current collector plate in the width direction.

[0011] The third non-aqueous electrolyte secondary battery according to this disclosure comprises an electrode body in which a positive electrode having a positive electrode mixture layer formed on both sides of a strip-shaped positive electrode core and a negative electrode having a negative electrode mixture layer formed on both sides of a strip-shaped negative electrode core are wound together via a separator, and a cylindrical outer casing for housing the electrode body, wherein in the deployed state of the positive electrode, a portion in the longitudinal direction has an uncoated portion in the width direction where the positive electrode mixture layer is not formed on the positive electrode core, and a current collecting tab is joined to the uncoated portion of the positive electrode, and in the deployed state of the negative electrode, a portion in the longitudinal direction has a width direction This is a non-aqueous electrolyte secondary battery having a first uncoated negative electrode portion where the negative electrode mixture layer is not formed over the entire length of the negative electrode core, a second current collector tab is bonded to the first uncoated negative electrode portion, and the inner circumferential region that does not face the positive electrode has negative electrode double-sided coated portions on both sides, including both ends in the width direction, and a second uncoated negative electrode portion in the central region of the inner circumferential region, which includes the center in the width direction and is sandwiched between the two negative electrode double-sided coated portions, where the negative electrode mixture layer is not formed on at least one side.

[0012] The non-aqueous electrolyte secondary battery according to this disclosure can suppress the occurrence of internal gaps in the electrode body and suppress deformation of the inner circumference portion of the negative electrode.

[0013] For example, in the first non-aqueous electrolyte secondary battery, multiple uncoated portions are formed on the positive electrode. In the unfolded state of the negative electrode, the inner circumferential region not facing the positive electrode has a negative electrode double-sided coated portion in a first region that overlaps with the uncoated portion of the positive electrode in the width direction, with a negative electrode mixture layer formed on both sides in at least a part of the longitudinal direction. This suppresses the generation of internal gaps in the electrode body in the portion that overlaps with the uncoated portion of the positive electrode in the width direction. Furthermore, the inner circumferential region of the negative electrode has a negative electrode uncoated portion in a second region that differs from the uncoated portion of the positive electrode in the width direction, located on one side in the width direction of the negative electrode double-sided coated portion in the first region, adjacent to the negative electrode mixture layer in the longitudinal direction, with at least one side not having a negative electrode mixture layer formed. This suppresses the tightening of the inner circumferential portion of the negative electrode regardless of the presence of the negative electrode double-sided coated portion in the inner circumferential region. Therefore, deformation of the inner circumferential portion of the negative electrode can be suppressed.

[0014] Furthermore, in the second non-aqueous electrolyte secondary battery, a first uncoated negative electrode portion is formed along the entire longitudinal direction at one end in the width direction of the negative electrode, and this first uncoated negative electrode portion is joined to a current collector plate joined to the inner surface of the bottom of the outer casing. In this configuration, gaps tend to easily occur in the electrode body on the side opposite to the current collector plate in the axial direction, but the negative electrode double-sided coating portion provided in the inner circumference region of the negative electrode can suppress the occurrence of internal gaps in the electrode body. In addition, in the above configuration, the clamping force tends to be excessive on the current collector plate side in the axial direction of the electrode body, but the length of the second uncoated negative electrode portion in the longitudinal direction of the negative electrode decreases from the current collector plate side in the width direction toward the side opposite to the current collector plate. As a result, clamping of the inner circumference portion of the negative electrode can be suppressed regardless of the presence of the negative electrode double-sided coating portion in the inner circumference region. Therefore, deformation of the inner circumference portion of the negative electrode can be suppressed.

[0015] Furthermore, in the third non-aqueous electrolyte secondary battery, an uncoated portion of the positive electrode and a first uncoated portion of the negative electrode are formed in a portion of the longitudinal direction of the positive electrode and the entire widthwise direction of the negative electrode, respectively, a first current collector tab is joined to the uncoated portion of the positive electrode, and a second current collector tab is joined to the first uncoated portion of the negative electrode. In this configuration, gaps tend to occur near both ends in the axial direction of the electrode body, but the occurrence of internal gaps in the electrode body can be suppressed by the negative electrode double-sided coating portions provided in both sides of the inner circumference region of the negative electrode, including both ends in the widthwise direction. In addition, in the above configuration, the clamping force tends to be excessive in the central region in the axial direction of the electrode body, but in the central region of the inner circumference region of the negative electrode, sandwiched between the two negative electrode double-sided coating portions, there is an uncoated portion of the negative electrode where a negative electrode mixture layer is not formed on at least one side. As a result, it is possible to suppress the clamping of the inner circumference portion of the negative electrode regardless of the presence of the negative electrode double-sided coating portion in the inner circumference region. Therefore, deformation of the inner circumference portion of the negative electrode can be suppressed.

[0016] This is a cross-sectional view along the axial direction of the non-aqueous electrolyte secondary battery of the embodiment. This is a perspective view of the electrode body constituting the non-aqueous electrolyte secondary battery of the embodiment. This is an unfolded view of the positive electrode of the embodiment. This is a diagram showing the outer surface of the negative electrode in the unfolded state of the embodiment. This is a diagram showing the inner surface of the negative electrode in the unfolded state of the embodiment. This is an enlarged view of the starting end of the negative electrode shown in Figure 4. This is a schematic diagram of a cross-section perpendicular to the axial direction of the inner circumferential portion of the electrode body corresponding to the C-C cross-section in Figure 4 of the embodiment. This is a schematic diagram of a cross-section perpendicular to the axial direction of the inner circumferential portion of the electrode body corresponding to the D-D cross-section in Figure 4 of the embodiment. This is a diagram corresponding to Figure 6 for the negative electrode of a comparative example non-aqueous electrolyte secondary battery. This is a diagram corresponding to Figure 7 for the negative electrode of a comparative example non-aqueous electrolyte secondary battery. This is an unfolded view of the positive electrode of another example non-aqueous electrolyte secondary battery of the embodiment. This is a diagram showing the outer surface of the negative electrode in the unfolded state of the non-aqueous electrolyte secondary battery This figure shows the outer side of the negative electrode in its unfolded state in another embodiment of a non-aqueous electrolyte secondary battery. This figure shows the outer side of the negative electrode in its unfolded state in another embodiment of a non-aqueous electrolyte secondary battery.

[0017] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, specific shapes, materials, numerical values, directions, etc., are examples to facilitate understanding of the present invention and can be appropriately modified to suit the specifications of the non-aqueous electrolyte secondary battery. Furthermore, the term "abbreviated" below is used to include, for example, cases where they are exactly the same, as well as cases where they can be considered substantially the same. Moreover, when multiple embodiments and modifications are included below, it is intended from the outset that their characteristic parts may be appropriately combined and used.

[0018] Figure 1 is a cross-sectional view along the axial direction of the non-aqueous electrolyte secondary battery 10 of the embodiment. Figure 2 is a perspective view of the electrode body 14 constituting the non-aqueous electrolyte secondary battery 10. Figure 3 is an unfolded view of the positive electrode 11. Figure 4 is a view showing the outer side of the winding in the unfolded state of the negative electrode 12. Figure 5 is a view showing the inner surface of the winding in the unfolded state of the negative electrode 12. Figure 6 is an enlarged view of the winding start end of the negative electrode 12 shown in Figure 4.

[0019] As shown in Figure 1, the non-aqueous electrolyte secondary battery 10 comprises a wound electrode body 14, a non-aqueous electrolyte (not shown), an outer casing 15, and a sealing body 16. The wound electrode body 14 has a positive electrode 11, a negative electrode 12, and a separator 13, and as shown in Figure 2, the positive electrode 11 and the negative electrode 12 are wound in a spiral shape via the separator 13. Hereafter, one axial side of the electrode body 14 may be referred to as "upper," and the other axial side as "lower." The outer casing 15 is a bottomed cylindrical shape that houses the electrode body 14 and the electrolyte. Hereafter, the non-aqueous electrolyte secondary battery 10 will be referred to as secondary battery 10.

[0020] The non-aqueous electrolyte has ionic conductivity (e.g., lithium ion conductivity). The non-aqueous electrolyte comprises a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. The non-aqueous electrolyte is not limited to a liquid electrolyte (non-aqueous electrolyte solution), but may also be a solid electrolyte using a gel-like polymer or the like. The secondary battery 10 is preferably a lithium-ion battery. The electrolyte salt may be, for example, LiBF ４ LiPF ６ Lithium salts such as the above are used. Non-aqueous solvents include, for example, esters such as ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and methyl propionate (MP), as well as ethers, nitriles, amides, and mixed solvents of two or more of these. The non-aqueous solvent may contain halogen-substituted products in which at least some of the hydrogen atoms of these solvents are replaced with halogen atoms such as fluorine.

[0021] Examples of halogen-substituted compounds include fluorinated cyclic carbonates such as fluoroethylene carbonate (FEC), fluorinated linear carbonates, and fluorinated linear carboxylic acid esters such as methyl fluoropropionate (FMP). In terms of suppressing the deterioration of the charge-discharge cycle characteristics of non-aqueous electrolyte secondary batteries or improving the input characteristics, the non-aqueous electrolyte preferably contains 5% by mass or more of FEC relative to the mass of the non-aqueous electrolyte, and more preferably contains 5% to 15% by mass of FEC.

[0022] As solid electrolytes, for example, solid or gel-like polymer electrolytes, inorganic solid electrolytes, etc., are used. Polymer electrolytes include, for example, a lithium salt and a matrix polymer, or a non-aqueous solvent, a lithium salt and a matrix polymer. As matrix polymers, for example, polymer materials that absorb non-aqueous solvents and gel are used. As polymer materials, for example, fluororesins, acrylic resins, polyether resins, etc., are used. As inorganic solid electrolytes, for example, materials known for all-solid-state lithium-ion secondary batteries, etc. (for example, oxide-based solid electrolytes, sulfide-based solid electrolytes, halide-based solid electrolytes, etc.) are used.

[0023] As shown in Figure 2, six positive electrode tabs, which are current-collecting tabs, are joined to the positive electrode 11 and electrically connected. Each positive electrode tab 20 is a conductive member for electrically connecting the positive electrode core 30 (Figure 3), which constitutes the positive electrode 11, to the positive electrode terminal, and extends from the upper end of the positive electrode core 30 in one axial direction (upwards) of the electrode body 14.

[0024] The negative electrode 12 is formed to be slightly larger than the positive electrode 11 in order to suppress lithium deposition, and is longer than the positive electrode 11 in both the longitudinal and widthwise (short-side) directions. The two separators 13 are also formed to be at least slightly larger than the positive electrode 11 and are arranged to sandwich the positive electrode 11. The separators 13 protrude upward above the positive electrode 11 and the negative electrode 12, while the negative electrode 12 protrudes downward above the positive electrode 11 and the separators 13.

[0025] The negative electrode 12 has a first uncoated negative electrode portion 41a, which is an exposed core portion of the negative electrode core 40 where the negative electrode mixture layer 42 is not provided, extending from the beginning end to the end end in the longitudinal direction of the elongated negative electrode 12 at its lower axial end. Therefore, the lower axial end of the electrode body 14 is composed of the exposed core portion of the negative electrode. The negative electrode 12 may constitute the beginning end of the electrode body 14. However, generally, the separator 13 extends beyond the beginning end of the negative electrode 12, and the beginning end of the separator 13 becomes the beginning end of the electrode body 14. On the other hand, in this example, the negative electrode 12 constitutes the end end of the electrode body 14. Therefore, the negative electrode 12 extends beyond the end end of the separator 13. The exposed surface of the negative electrode core 40, described later, exposed on the outer circumferential surface of the negative electrode 12, contacts the inner circumferential surface of the outer can 15 and is electrically connected.

[0026] Referring to Figure 3, the positive electrode 11 has a strip-shaped positive electrode core 30 and a positive electrode mixture layer 32 formed on both sides of the positive electrode core 30. The positive electrode core 30 can be made of, for example, a metal foil such as aluminum, or a film with the metal arranged on its surface. A preferred positive electrode core 30 is a metal foil mainly composed of aluminum or an aluminum alloy. The thickness of the positive electrode core 30 is, for example, 10 μm to 30 μm.

[0027] The positive electrode mixture layer 32 preferably contains a positive electrode active material, a conductive agent, and a binder. The positive electrode 11 is manufactured by applying a positive electrode mixture slurry containing a positive electrode active material, a conductive agent, a binder, and a solvent such as N-methyl-2-pyrrolidone (NMP) to both sides of the positive electrode core 30, followed by drying and rolling.

[0028] Examples of positive electrode active materials include lithium-containing transition metal oxides containing transition metal elements such as Co, Mn, and Ni. While lithium-containing transition metal oxides are not particularly limited, they generally have the formula Li １＋ｘ MO ２ It is preferable that the composite oxide is represented by the formula (wherein -0.2 < x ≤ 0.2, and M includes at least one of Ni, Co, Mn, and Al).

[0029] Examples of the conductive agents mentioned above include acetylene black (AB), carbon black (CB) such as Ketjenblack, and carbon materials such as graphite. Examples of the binders mentioned above include fluororesins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyimide (PI), acrylic resins, and polyolefin resins. These resins may also be used in combination with carboxymethylcellulose (CMC) or its salts, polyethylene oxide (PEO), etc. These may be used individually or in combination of two or more types.

[0030] As shown in Figure 3, in the unfolded state of the positive electrode 11, there are six uncoated positive electrode portions 31 at multiple positions in the longitudinal direction X1 (six positions in the example of Figure 3) where the surface of the metal constituting the positive electrode core 30 is exposed in part of the width direction Y1. The width direction Y1 of the positive electrode 11 coincides with the axial direction G in the wound state (Figure 1). The uncoated positive electrode portions 31 are the parts to which the positive electrode tabs 20 are joined, and are the parts on the surface of the positive electrode core 30 where the positive electrode mixture layer has not been formed. Preferably, the uncoated positive electrode portions 31 are formed in positions that overlap when viewed in the thickness direction on both sides of the positive electrode 11, and the positive electrode tabs 20 are joined to only one side, but the uncoated positive electrode portions may also be formed on only one side of the positive electrode 11. In Figure 3, the positive electrode mixture layer 32 is shown as a sandy area. The six positive electrode tabs 20 are joined to the six uncoated positive electrode portions 31, for example, by ultrasonic welding. The positive electrode tab 20 is covered with insulating tape (not shown), thereby preventing a short circuit between the positive electrode 11 and the negative electrode 12.

[0031] The constituent material of the positive electrode tab 20 is not particularly limited. Preferably, the positive electrode tab 20 is made of a metal mainly composed of aluminum.

[0032] In Figure 3, the six uncoated positive electrode portions 31 are evenly distributed along the longitudinal direction X1 of the positive electrode 11, but the multiple uncoated positive electrode portions 31 may be unevenly distributed along the longitudinal direction X1.

[0033] Next, the configuration of the negative electrode 12 will be explained using Figures 4 to 6. Figure 4 shows the outer side of the negative electrode 12, i.e., the outer circumference side, and Figure 5 shows the inner side of the negative electrode 12, i.e., the inner circumference side. The negative electrode 12 has a strip-shaped negative electrode core 40 and negative electrode mixture layers 42 formed on both sides of the negative electrode core 40. In Figures 4 to 6, the negative electrode mixture layers 42 are shown as sandy areas. For the negative electrode core 40, for example, a metal foil such as copper, or a film with the metal arranged on the surface layer can be used. The thickness of the negative electrode core 40 is, for example, 5 μm to 30 μm.

[0034] The negative electrode mixture layer 42 preferably contains a negative electrode active material and a binder. The negative electrode 12 is manufactured by, for example, applying a negative electrode mixture slurry containing a negative electrode active material, a binder, and water to both sides of the negative electrode core, and then drying and rolling it.

[0035] The negative electrode active material is not particularly limited as long as it can reversibly intercept and release lithium ions. For example, carbon materials such as natural graphite and artificial graphite, metals that alloy with lithium such as Si and Sn, or alloys and composite oxides containing these can be used. The binder contained in the negative electrode active material layer is, for example, the same resin as in the case of the positive electrode 11. When preparing the negative electrode mixture slurry with an aqueous solvent, styrene-butadiene rubber (SBR), CMC or its salts, polyacrylic acid or its salts, polyvinyl alcohol, etc. can be used. These may be used individually or in combination of two or more.

[0036] A porous sheet having ion permeability and insulating properties is used for the separator 13 (Figure 2). Specific examples of porous sheets include microporous thin films, woven fabrics, and nonwoven fabrics. The material of the separator 13 is preferably an olefin resin such as polyethylene or polypropylene. The thickness of the separator 13 is, for example, 10 μm to 50 μm. The separator 13 is tending to become thinner as batteries become more high-capacity and high-power. The separator 13 has a melting point of, for example, 130°C to 180°C.

[0037] Furthermore, in the unfolded state of the negative electrode 12, the lower end, which is one end in the width direction Y2, has a first uncoated negative electrode portion 41a over the entire length direction X2 where the negative electrode mixture layer 42 is not formed. The first uncoated negative electrode portion 41a is joined to the current collector plate 52 which is joined to the bottom of the outer casing 15, as will be described later. The width direction Y2 of the negative electrode 12 coincides with the axial direction G (Figure 1) in the wound state.

[0038] Then, with the uncoated negative electrode portion 41d, which is the exposed portion of the negative electrode core 40, positioned on the outermost surface of the negative electrode 12, which is the outermost surface of the electrode body 14, a tape (not shown) is attached to the outermost surface.

[0039] In the example shown in Figure 1, the battery case is composed of an outer casing 15 and a sealing body 16. The sealing body 16 is formed by stacking an upper metal terminal cap sealing plate 27 and a lower metal current collector plate 50 having a through hole 50a, with a metal plate 51 sandwiched between them in the vertical direction. The sealing plate 27 is hat-shaped with its center bulging upwards. The outer casing 15 has an annular groove 35 formed by recessing the upper end of the cylindrical portion radially inward along its entire circumference. The sealing body 16 is fitted inward through the opening at the upper end of the cylindrical portion 15a of the outer casing 15 via a gasket 28, and while locked to the upper surface of the groove 35, the upper end of the cylindrical portion 15a is crimped radially inward. In this way, the sealing body 16 is crimped and fixed to the inside of the opening end of the outer casing 15 via the outer gasket 28.

[0040] An insulating plate 18 is provided on the upper side of the electrode body 14. The six positive electrode tabs 20 extend towards the sealing body 16 through through holes in the insulating plate 18, pass through through holes 50a in the current collector plate 50, and are joined by being sandwiched between the current collector plate 50 and the metal plate 51. In the secondary battery 10, the sealing plate 27, which is electrically connected to the current collector plate 50 and the metal plate 51, becomes the positive electrode terminal.

[0041] Furthermore, a current collector plate 52 is disposed below the electrode body 14. The first uncoated portion 41a of the negative electrode 12 formed at the lower end of the negative electrode 12 is pressed against and joined to the upper surface of the current collector plate 52 below the electrode body 14 in a state of being tilted radially inward. The current collector plate 52 is joined to the bottom plate portion 15b of the outer can 15. Thereby, the negative electrode 12 is electrically connected to the outer can 15 serving as a negative electrode terminal via the current collector plate 52.

[0042] As described above, when the positive electrode 11 has the positive electrode uncoated portion 31 (FIG. 3), in the negative electrode 12 of the electrode body 14, the portion facing the positive electrode uncoated portion 31 does not expand during charge and discharge. Therefore, in the electrode body 14, generally, a gap is likely to occur inside the portion that coincides with the axial direction G corresponding to the width direction Y1 of the positive electrode uncoated portion 31 and the positive electrode 11. An increase in the gap inside the electrode body 14 causes Li to precipitate on the negative electrode, which is undesirable.

[0043] On the other hand, in order to reduce the above-mentioned gap, it is conceivable to increase the winding direction length of the inner peripheral side region of the negative electrode that does not face the positive electrode 11 and provide an adhesive layer on both surfaces of the inner peripheral side region. However, in the electrode body 14, in a portion different from the positive electrode uncoated portion 31 in the axial direction, the above-mentioned gap is unlikely to occur. Therefore, in this portion, the tightening force by the inner peripheral side region provided with the adhesive layer may become excessive. As a result, deformation is likely to occur in the inner peripheral side portion of the negative electrode. In the present embodiment, in order to prevent such inconvenience, the first region A and the second region B are provided in the inner peripheral side region of the negative electrode 12. Hereinafter, the structure of the negative electrode, particularly the inner peripheral side region, will be described in detail with reference to FIGS. 4 to 7B.

[0044] FIG. 7A is a schematic cross-sectional view perpendicular to the axial direction of the inner peripheral side portion of the electrode body 14 corresponding to the C - C cross-section of FIG. 4. FIG. 7B is a schematic cross-sectional view perpendicular to the axial direction of the inner peripheral side portion of the electrode body 14 corresponding to the D - D cross-section of FIG. 4. In FIGS. 7A and 7B, the separator 13 is not shown.

[0045] As shown in FIGS. 4 to 6, the negative electrode 12 has an inner peripheral side region 70 (a region having a range in the longitudinal direction X2 indicated by an arrow α2 in FIGS. 4 and 5) that does not face the positive electrode in the wound state of the electrode body 14 at the winding start side end that is the inner peripheral side end. As shown in FIG. 6, the inner peripheral side region 70 has a first region A that overlaps at least a part of the positive electrode non-coated portion 31 (FIG. 3) in the width direction Y2, and a second region B that is different from the positive electrode non-coated portion 31 in the width direction Y2. The first region A has a negative electrode double-sided coated portion 42a in which negative electrode binder layers 42 are formed on both sides at least in a part of the longitudinal direction X2. In FIG. 6, a negative electrode non-coated portion 41c only on the outer winding surface is formed at the winding start side end of the first region A, but the negative electrode non-coated portion 41c may be omitted.

[0046] Also, in FIGS. 4 to 6, a region that coincides with the positive electrode non-coated portion 31 in the width direction Y2 is indicated by an arrow α1. In the example of FIG. 6, the length in the width direction Y2 of the first region A is smaller than the length in the width direction Y2 of the positive electrode non-coated portion coincidence region, but the length in the width direction Y2 of the first region A may be less than or equal to the length in the width direction Y2 of the positive electrode non-coated portion coincidence region, and may coincide with the length in the width direction Y2 of the positive electrode non-coated portion coincidence region.

[0047] The second region B is disposed on one side in the width direction (the lower side in FIG. 6) of the negative electrode double-sided coated portion 42a in the first region A, is adjacent to the negative electrode binder layer 42 in the longitudinal direction X2, and has a negative electrode non-coated portion 41b in which a negative electrode binder layer is not formed on at least one side. In this example, negative electrode binder layers are not formed on both sides of the negative electrode non-coated portion 41b, but a negative electrode binder layer may be formed on only one side.

[0048] In the second region B, a negative electrode double-sided coated portion 42b is provided so as to be adjacent to the winding end side of the negative electrode non-coated portion 41. The negative electrode double-sided coated portion in the second region B may be omitted.

[0049] Therefore, the negative electrode double-sided coating length LA in the longitudinal direction X2 of the negative electrode double-sided coated portion 42a in the first region A is larger than the negative electrode double-sided coating length LB in the longitudinal direction X2 of the negative electrode double-sided coated portion 42b in the second region B.

[0050] Thus, in this configuration, uncoated positive electrode portions 31 are formed at multiple positions on the positive electrode 11. In the unfolded state of the negative electrode 12, the inner circumferential region 70 that does not face the positive electrode 11 has a negative electrode double-sided coated portion 42a in at least a part of the longitudinal direction X2 in the first region A that overlaps with the uncoated positive electrode portion 31 in the width direction. As a result, as shown in Figure 7A, in the electrode body 14, the negative electrode double-sided coated portion 42a, which has a greater thickness, is arranged on the inner circumferential side of the portion that overlaps with the uncoated positive electrode portion 31 (Figure 3) in the width direction, so that the occurrence of internal gaps in this portion can be suppressed.

[0051] Furthermore, the inner circumferential region 70 of the negative electrode 12 is located in a second region B that differs in width from the uncoated positive electrode portion 31, and has an uncoated negative electrode portion 41b positioned on one side in the width direction of the negative electrode double-sided coated portion 42a in the first region A, adjacent to the negative electrode mixture layer 42 in the longitudinal direction. As a result, as shown in Figure 7B, the tightening of the inner circumferential portion of the negative electrode 12 can be suppressed regardless of the presence of the negative electrode double-sided coated portions 42a (Figure 7A) and 42b in the inner circumferential region 70. Therefore, deformation of the inner circumferential portion of the negative electrode 12 can be suppressed. Thus, a secondary battery 10 can be obtained that can suppress the occurrence of internal gaps in the electrode body 14 and suppress deformation of the inner circumferential portion of the negative electrode 12.

[0052] Furthermore, it is preferable that the length in the width direction Y2 of the first region A is greater than 1 / 5 of the total length in the width direction Y2 of the negative electrode 12. With this configuration, the length in the width direction Y2 of the negative electrode double-sided coated portion 42a, which is long in the longitudinal direction X2 in the inner circumferential region 70, can be increased, thereby further suppressing the occurrence of internal gaps in the electrode body 14.

[0053] Furthermore, it is preferable that in the second region B, there is no region where the negative electrode mixture layer is formed on both sides, or that the negative electrode mixture layer 42 is provided within 0.8 turns in the winding state of the negative electrode 12. With this configuration, the tightening force due to the formed portion of the negative electrode mixture layer 42 on the inner circumference side of the negative electrode 12 can be further suppressed, thereby further suppressing deformation of the inner circumference side of the negative electrode 12.

[0054] Furthermore, it is preferable that the negative electrode double-sided coated portion 42a is provided in the first region A for at least 1.0 turn of the negative electrode 12 in its wound state. With this configuration, the longitudinal length X2 of the negative electrode double-sided coated portion 42a in the region overlapping in the width direction with the positive electrode uncoated portion 31 in the inner circumferential region 70 can be increased, thereby further suppressing the occurrence of internal gaps in the electrode body 14.

[0055] Figure 8 is a diagram of the negative electrode 12a of the comparative example secondary battery, corresponding to Figure 6. Figure 9 is a diagram of the negative electrode 12a, corresponding to Figure 7. In the comparative example, unlike the embodiments shown in Figures 1 to 7B, a negative electrode double-sided coating portion 42a1 is formed in the inner circumferential region 70, indicated by arrow α2 in the longitudinal direction X2. On the other hand, in the inner circumferential region 70, an uncoated negative electrode portion 41f is formed only on the outer surface of the winding start end, and a first uncoated negative electrode portion 41a is formed. However, these are located on one side in the width direction of the negative electrode double-sided coating portion in the region that overlaps with the positive electrode uncoated portion 31 (see Figure 3) in the width direction Y2, and no negative electrode uncoated portion is formed adjacent to the negative electrode mixture layer in the longitudinal direction. In such a comparative example, since the negative electrode mixture layer 42 is formed over almost the entire width direction Y2, it is possible to suppress the occurrence of internal gaps in the electrode body 14, but deformation of the inner circumferential portion of the negative electrode 12 is likely to occur. According to the above embodiment, such inconveniences can be prevented.

[0056] To confirm the effects of the above embodiment, the inventors conducted experiments to check the innermost circumferential gap in the region that coincides with the uncoated portion 31 of the positive electrode in the width direction, and the presence or absence of deformation in the portion of the negative electrode facing the positive electrode, while varying the combination of negative electrode coating lengths LA and LB in the first region A and the second region B. The experiments were conducted in five types: Comparative Examples 1 to 4 and the embodiment.

[0057] The configuration of the embodiment is the same as the configuration shown in Figures 1 to 7B, with the negative electrode double-sided coating length LA of the negative electrode double-sided coating section 42a in the first region A being 1.8 turns, and the negative electrode double-sided coating length LB of the negative electrode double-sided coating section 42b in the second region B being 0.5 turns. In each of Comparative Examples 1 to 4, the negative electrode double-sided coating lengths LA and LB of the first region A and the second region B are the same. In Comparative Example 1, the negative electrode double-sided coating lengths LA and LB are 0.5 turns. In Comparative Example 2, the negative electrode double-sided coating lengths LA and LB are 0.8 turns. In Comparative Example 3, the negative electrode double-sided coating lengths LA and LB are 1.3 turns. In Comparative Example 4, the negative electrode double-sided coating lengths LA and LB are 1.8 turns. In each of Comparative Examples 1 to 4, the only difference is the negative electrode double-sided coating lengths LA and LB of the first region A and the second region B, otherwise it is the same as the embodiment.

[0058] The innermost circumferential gap and the presence or absence of deformation were confirmed by taking cross-sectional photographs of the electrode body 14 using an X-ray CT scanner (X-ray computed tomography scanner) after a predetermined charge-discharge cycle was completed in the secondary battery. Table 1 shows the experimental results.

[0059]

[0060] As shown in Table 1, in Comparative Examples 1 and 2, where the coating lengths LA and LB on both sides of the negative electrode in the first region A and the second region B were the same and the coating length was 0.8 turns or less, no deformation occurred in the portion of the negative electrode facing the positive electrode, but the innermost circumferential gap increased. On the other hand, in Comparative Examples 3 and 4, where the coating lengths LA and LB on both sides of the negative electrode in the first region A and the second region B were the same and the coating length on both sides of the negative electrode was 1.3 turns or more, the innermost circumferential gap decreased, but deformation occurred in the portion of the negative electrode facing the positive electrode.

[0061] On the other hand, in an embodiment where the negative electrode double-sided coating length LA in the first region A is longer than the negative electrode double-sided coating length LB in the second region B, it was confirmed that the innermost circumferential gap could be made sufficiently small and that there was no deformation in the positive electrode-facing portion of the negative electrode 12.

[0062] Figure 10 is an unfolded view of the positive electrode 11a of a secondary battery in another embodiment. Figure 11 is a view of the outer side of the negative electrode 12b in the unfolded state in another secondary battery.

[0063] In this example, the positive electrode 11a does not have multiple positive electrode tabs. Therefore, the positive electrode 11a does not have multiple uncoated positive electrode portions formed only in a portion of the width direction. Instead, the positive electrode has an uncoated positive electrode portion 31a in the middle of the longitudinal direction X1, which is a part of the longitudinal direction X1 in the unfolded state, where the positive electrode mixture layer 32 of the positive electrode core body 30 is not formed, extending over the entire width direction Y1. A positive electrode tab 20a is bonded to the uncoated positive electrode portion 31a. The positive electrode tab 20a is connected, for example, to an internal terminal plate (not shown) that constitutes a sealing body. The internal terminal plate is electrically connected to the sealing plate that constitutes the sealing body via metal parts such as an upper valve body and a lower valve body.

[0064] Such a configuration does not involve only a portion of the negative electrode's width direction facing the uncoated portion of the positive electrode. On the other hand, in this example, as shown in Figure 11, the first uncoated negative electrode portion 41a is formed over the entire length X2 at the lower end, which is one end in the width direction Y2 of the negative electrode 12b. The first uncoated negative electrode portion 41a is joined to the current collector plate 52 (see Figure 1) which is joined to the inner surface of the bottom of the outer casing 15. In this case, a difference in clamping force tends to occur in the axial direction of the electrode body during charging and discharging of the secondary battery. Specifically, if the negative electrode is uniformly coated on both sides or uncoated, except for the first uncoated negative electrode portion 41a of the negative electrode 12b, and the inner circumference region 70 (the region indicated by arrow α2 in the longitudinal direction X2 in Figure 11) that does not face the positive electrode 11a, then the clamping force on the inner circumference of the electrode body will be excessive on the side where it connects to the current collector plate 52, and a gap may be formed on the inner circumference of the electrode body on the side opposite to the current collector plate 52. In this example, to prevent such problems, the length of the uncoated negative electrode portion in the inner circumference region 70 is varied according to its position in the width direction.

[0065] Specifically, the inner circumference region 70 of the negative electrode 12b has a negative electrode double-sided coated portion 42c in the width direction Y2, including the end opposite to the current collector plate 52 (see Figure 1) (upper end of Figure 11), where a negative electrode mixture layer 42 is formed on both sides. In addition, in the inner circumference region 70, on the same side as the current collector plate 52 in the width direction Y2 (lower side of Figure 11), there is a second negative electrode uncoated portion 41g connected to the first negative electrode uncoated portion 41a, where a negative electrode mixture layer is not formed on at least one side. In this example, the second negative electrode uncoated portion 41g does not have a negative electrode mixture layer formed on both sides of the negative electrode core body 40, but it is also possible to have a configuration where the negative electrode mixture layer is not formed on only one side.

[0066] The starting edge La of the coated portion 42c on both sides of the negative electrode is inclined toward the starting edge toward the side opposite to the current collector plate 52. As a result, the length of the second uncoated portion 41g of the negative electrode 12b in the longitudinal direction X2 decreases from the lower side, which is on the current collector plate 52 side, toward the upper side, which is opposite to the current collector plate 52, in the width direction Y2.

[0067] In this example, the uncoated portion 41a of the first negative electrode is joined to the current collector plate 52 which is joined to the inner surface of the bottom of the outer can 15. As a result, gaps tend to easily occur in the electrode body on the side opposite to the current collector plate 52 in the axial direction. However, the double-sided coated portion 42c of the negative electrode provided in the inner circumference region 70 of the negative electrode 12b suppresses the occurrence of internal gaps in the electrode body. Furthermore, in a configuration where the uncoated portion 41a of the first negative electrode is joined to the current collector plate 52 which is joined to the inner surface of the bottom of the outer can 15, the clamping force tends to be excessive on the current collector plate 52 side in the axial direction of the electrode body. However, the length of the uncoated portion 41g of the second negative electrode in the longitudinal direction of the negative electrode 12b decreases from the current collector plate 52 side in the width direction Y2 toward the side opposite to the current collector plate 52. As a result, regardless of the presence of the double-sided coated portion 42c of the negative electrode in the inner circumference region 70, the clamping of the inner circumference portion of the negative electrode 12b can be suppressed. Therefore, deformation of the inner circumference portion of the negative electrode 12 can be suppressed. In this example, the other configurations and operations are the same as those in Figures 1 to 7B.

[0068] Figure 12 shows the outer side view of the negative electrode 12c in its unfolded state in another embodiment of a secondary battery. The positive electrode in this example is the same as in Figure 11. In this example, the end edge of the negative electrode coating portion 42d on both sides of the negative electrode 12c on the winding start side changes in a stepped manner toward the winding start side toward the opposite side of the current collector plate. As a result, the length of the second uncoated negative electrode portion 41g in the longitudinal direction X2 of the negative electrode 12c decreases in a stepped manner toward the upper side toward the opposite side of the current collector plate 52 in the width direction Y2.

[0069] Even with the configuration in this example, similar to the configurations in Figures 10 to 11, the occurrence of internal gaps in the electrode body can be suppressed, and the tightening of the inner circumference of the negative electrode 12c can be suppressed, thereby suppressing deformation of the inner circumference of the negative electrode 12c. In this example, the other configurations and operations are the same as those in Figures 1 to 7B, or Figures 10 to 11.

[0070] In addition, the configurations in Figures 10 to 11 and Figure 12 described above describe a case in which, as shown in Figure 10, the positive electrode has an uncoated portion 31a in which the positive electrode compound layer 32 of the positive electrode core body 30 is not formed, in a part of the longitudinal direction X1 in the unfolded state and over the entire width direction Y1, and the positive electrode tab 20a is joined to the uncoated portion 31a. On the other hand, in the configurations in Figures 10 to 11 and Figure 12 described above, similar to the configurations in Figures 1 to 7B, the positive electrode can also have an uncoated portion in which the positive electrode compound layer of the positive electrode core body is not formed, in a part of the width direction at multiple positions in the longitudinal direction of the unfolded state of the positive electrode, and a positive electrode tab, which is a current collecting tab, is joined to each of the multiple uncoated portions of the positive electrode. In this case as well, similar to the negative electrode configuration shown in Figures 10 to 11, or Figure 12, in the deployed state of the negative electrode, the inner circumference region that does not face the positive electrode has a negative electrode double-sided coated portion in the region including the end opposite to the current collector plate 52 (Figure 1) in the width direction, where a negative electrode mixture layer is formed on both sides. In the inner circumference region, on the same side as the current collector plate 52 in the width direction, there may be a second negative electrode uncoated portion 41g (Figure 11) or second negative electrode uncoated portion 41g (Figure 12) connected to the first negative electrode uncoated portion 41a (Figure 11 or Figure 12), where a negative electrode mixture layer is not formed on at least one side. Furthermore, the length of the second negative electrode uncoated portion in the longitudinal direction of the negative electrode may decrease from the current collector plate 52 side toward the opposite side in the width direction of the negative electrode. For example, as shown in the configuration of Figure 11, the length of the second unpainted portion 41g of the negative electrode 12b in the longitudinal direction X2 may be continuously decreasing from the lower side, which is on the current collector plate 52 side in the width direction Y2, to the upper side, which is on the opposite side of the current collector plate 52. Alternatively, as shown in the configuration of Figure 12, the length of the second unpainted portion 41g of the negative electrode 12c in the longitudinal direction X2 may be stepped in decreasing from the lower side, which is on the current collector plate 52 side in the width direction Y2, to the upper side, which is on the opposite side of the current collector plate 52. With these configurations, regardless of the configuration in which the first unpainted portion 41a of the negative electrode is joined to the current collector plate 52 which is joined to the inner surface of the bottom of the outer casing 15, the occurrence of internal gaps in the electrode body can be suppressed, and the tightening of the inner circumference portion of the negative electrode can be suppressed, thereby suppressing deformation of the inner circumference portion of the negative electrode.

[0071] Figure 13 shows the outer side of the negative electrode 12d in its unfolded state in another embodiment of the secondary battery. Figure 14 shows the outer side of the negative electrode 12d in its unfolded state.

[0072] In this example configuration, similar to the configurations in Figures 11 and 12, the positive electrode 11a has an uncoated portion 31a extending over its entire width in the middle of the longitudinal direction, which is a part of the longitudinal direction when unfolded, and the positive electrode tab 20a is joined to the uncoated portion 31a.

[0073] Furthermore, in this example, no uncoated negative electrode portion is formed at one end of the negative electrode 12d in the width direction Y2, extending over the entire length in the longitudinal direction X2. Instead, in this example, the negative electrode 12d has a first uncoated negative electrode portion 41j at the winding start end, which is part of the longitudinal direction X2 in the unfolded state, where the negative electrode mixture layer of the negative electrode core body 40 is not formed over the entire width direction Y2. A second current collector tab, the negative electrode tab 19, is joined to the first uncoated negative electrode portion 41j. The portion of the negative electrode tab 19 that protrudes downward is directly joined to the bottom of the outer casing 15. An uncoated negative electrode portion 41k is formed at the winding end end of the negative electrode, extending over the entire length in the width direction. The uncoated negative electrode portion 41k may be omitted.

[0074] Even with this configuration, a difference in clamping force tends to occur in the axial direction of the electrode body during charging and discharging of the secondary battery. Specifically, near both ends in the width direction of the negative electrode 12d and the positive electrode 11a, the negative electrode 12d and the positive electrode 11a tend to expand and contract in the axial direction, so the clamping force in the radial direction of the electrode body is less likely to be excessive, and conversely, an internal gap tends to be formed. On the other hand, in the middle part of the width direction of the negative electrode 12d, expansion during charging and discharging causes the clamping force on the inner circumference of the electrode body to become excessive, and deformation of the inner circumference of the negative electrode 12d tends to occur. In this example, in order to prevent such problems, the length of the uncoated portion of the negative electrode in the inner circumference region 70 is changed according to the width direction position.

[0075] Specifically, the inner circumferential region 70 of the negative electrode 12d that does not face the positive electrode 11a has a negative electrode double-sided coated portion 42e on both sides, including both ends in the width direction Y2, where a negative electrode mixture layer 42 is formed on both sides. Furthermore, the central region of the inner circumferential region 70, including the center in the width direction and sandwiched between the two negative electrode double-sided coated portions 42e, has a negative electrode uncoated portion 41h where a negative electrode mixture layer is not formed on at least one side. In this example, the negative electrode uncoated portion 41h does not have a negative electrode mixture layer formed on both sides of the negative electrode core body 40, but it is also possible to have a configuration where a negative electrode mixture layer is not formed on only one side.

[0076] In this example, despite the tendency for gaps to easily occur near both ends of the electrode body in the axial direction, the negative electrode double-sided coating portions 42e provided on both sides of the inner circumferential region 70 of the negative electrode 12d in the width direction Y2 can suppress the occurrence of internal gaps in the electrode body. Furthermore, although the clamping force tends to be excessive in the central region in the axial direction of the electrode body, the central region of the inner circumferential region 70 of the negative electrode 12d, sandwiched between the two negative electrode double-sided coating portions 42e, has an uncoated negative electrode portion 41h where the negative electrode mixture layer is not formed on at least one side. As a result, the clamping of the inner circumferential portion of the negative electrode 12d can be suppressed regardless of the presence of the negative electrode double-sided coating portions 42e in the inner circumferential region 70. Therefore, deformation of the inner circumferential portion of the negative electrode 12d can be suppressed. The first uncoated negative electrode portion 41j may be provided in the longitudinal middle portion of the negative electrode or at the end of the winding end of the negative electrode. Furthermore, the first uncoated portion of the negative electrode may be provided at multiple positions along the longitudinal direction of the negative electrode. In this example, the other configurations and functions are the same as those in Figures 1 to 7B, or Figures 10 to 11.

[0077] 10 Non-aqueous electrolyte secondary battery, 11, 11a Positive electrode, 12, 12a, 12b, 12c, 12d Negative electrode, 13 Separator, 14 Electrode body, 15 Outer can, 16 Sealing body, 18 Insulating plate, 19 Negative electrode tab, 20 Positive electrode tab, 27 Sealing plate, 28 Gasket, 30 Positive electrode core, 31, 31a Uncoated positive electrode portion, 32 Positive electrode mixture layer, 40 Negative electrode core, 41a-41k Uncoated negative electrode portion, 42a-42e Negative electrode double-sided coated portion, A First region, B Second region.

Claims

1. The electrode body comprises a positive electrode in which a positive electrode core body with a positive electrode mixture layer formed on both sides and a negative electrode core body with a negative electrode mixture layer formed on both sides are wound together via a separator, and a cylindrical outer container housing the electrode body, wherein, at multiple positions in the longitudinal direction of the deployed state of the positive electrode, a portion in the width direction has an uncoated positive electrode portion where the positive electrode mixture layer is not formed on the positive electrode core body, and a current collector tab is joined to each of the multiple uncoated positive electrode portions. In the deployed state of the negative electrode, the inner circumferential region not facing the positive electrode includes a first region that overlaps with the uncoated portion of the positive electrode in the width direction, and has a negative electrode double-sided coated portion in at least a part of the longitudinal direction, on both sides of which the negative electrode mixture layer is formed; and a second region that differs from the uncoated portion of the positive electrode in the width direction, and is located on one side in the width direction of the negative electrode double-sided coated portion in the first region, is adjacent to the negative electrode mixture layer in the longitudinal direction, and has a negative electrode uncoated portion on at least one side on which the negative electrode mixture layer is not formed.

2. The electrode body comprises a positive electrode in which a positive electrode has a positive electrode mixture layer formed on both sides of a strip-shaped positive electrode core, and a negative electrode has a negative electrode mixture layer formed on both sides of a strip-shaped negative electrode core, wound together with a separator, and a cylindrical outer can that houses the electrode body, wherein, in the deployed state of the positive electrode, at multiple positions in the longitudinal direction, a portion in the width direction has an uncoated portion in which the positive electrode mixture layer is not formed on the positive electrode core, and a current collector tab is joined to each of the multiple uncoated portions, or, in the deployed state of the positive electrode, a portion in the longitudinal direction has an uncoated portion in which the positive electrode mixture layer is not formed on the positive electrode core over the entire width direction, and a current collector tab is joined to the uncoated portion, and, in the deployed state of the negative electrode, at one end in the width direction, there is a first uncoated portion in the longitudinal direction in which the negative electrode mixture layer is not formed. The first uncoated negative electrode portion is joined to a current collector plate joined to the inner surface of the bottom of the outer casing, and in the deployed state of the negative electrode, the inner circumferential region not facing the positive electrode has a negative electrode double-sided coated portion in the region including the end opposite to the current collector plate in the width direction, where the negative electrode mixture layer is formed on both sides, and in the inner circumferential region, on the same side as the current collector plate in the width direction, there is a second uncoated negative electrode portion connected to the first uncoated negative electrode portion, where the negative electrode mixture layer is not formed on at least one side, and the length of the second uncoated negative electrode portion in the longitudinal direction of the negative electrode decreases from the current collector plate side to the side opposite the current collector plate in the width direction, non-aqueous electrolyte secondary battery.

3. The electrode body comprises a positive electrode in which a positive electrode core body with a positive electrode mixture layer formed on both sides and a negative electrode core body with a negative electrode mixture layer formed on both sides are wound together via a separator, and a cylindrical outer container for housing the electrode body, wherein in the deployed state of the positive electrode, a portion of the longitudinal direction has an uncoated portion in the width direction where the positive electrode mixture layer is not formed on the positive electrode core body, and a current collector tab is joined to the uncoated portion of the positive electrode, and in the deployed state of the negative electrode, a portion of the longitudinal direction has a first uncoated portion in the width direction where the negative electrode mixture layer is not formed on the negative electrode core body, and a second current collector tab is joined to the first uncoated portion of the negative electrode, A non-aqueous electrolyte secondary battery, wherein the inner circumferential region not facing the positive electrode has a negative electrode double-sided coated portion on both sides of each of the two side regions including both ends in the width direction, and the central region of the inner circumferential region, including the center in the width direction and sandwiched between the two negative electrode double-sided coated portions, has a second negative electrode uncoated portion on at least one side where the negative electrode mixture layer is not formed.

4. The length in the width direction of the first region is less than or equal to the length in the width direction of the uncoated positive electrode portion, as described in claim 1.

5. The non-aqueous electrolyte secondary battery according to claim 1, wherein the length in the width direction of the first region is greater than 1 / 5 of the total length of the negative electrode in the width direction.

6. The non-aqueous electrolyte secondary battery according to claim 4 or claim 5, wherein the second region does not have a region in which the negative electrode mixture layer is formed on both sides, or the negative electrode mixture layer is provided within 0.8 turns in the winding state of the negative electrode.

7. The non-aqueous electrolyte secondary battery according to claim 6, wherein the negative electrode double-sided coating portion is provided in the first region for 1.0 turn or more in the winding state of the negative electrode.

Images