Secondary cell
Patent Information
- Application Number
- JP2023128737
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-08-07
- Publication Date
- 2025-02-20
Smart Images
Figure 2025024547000001_ABST
Abstract
Description
[Technical field]
[0001] The present disclosure relates to secondary batteries. [Background technology]
[0002] Due to the widespread use of various electronic devices such as mobile phones, secondary batteries have been developed as power sources that are small and lightweight and can obtain high energy density. These secondary batteries have a positive electrode, a negative electrode, and an electrolyte housed inside an exterior member, and various studies have been conducted on the configuration of the secondary battery (for example, see Patent Document 1).
[0003] For example, Patent Document 1 describes a sealed electricity storage device that includes an electrode assembly in which a positive electrode body and a negative electrode body are stacked or wound with a separator interposed therebetween, and an exterior case that houses the electrode body. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] JP 2019-46639 A Summary of the Invention [Problem to be solved by the invention]
[0005] Various studies have been conducted to improve the performance of secondary batteries, but there is still room for improvement in the performance of secondary batteries.
[0006] It is therefore desirable to provide a battery that has a high capacity while still having a compact configuration. [Means for solving the problem]
[0007] A battery according to an embodiment of the present disclosure includes a battery element, an exterior body, and a sealing body. The exterior body has a first bottom, a second bottom facing the first bottom in a first direction, and a side wall portion located between the first bottom and the second bottom and surrounding the battery element. The exterior body has, as the first bottom, a terminal member arranged adjacent to the battery element in the first direction and connected to the battery element, and an annular lid portion spaced apart from the terminal member and surrounding the terminal member without overlapping with the terminal member in a plan view viewed in the first direction. The exterior member has, as the second bottom and side wall portion, a housing portion joined to the lid portion and housing the battery element. The sealing body is arranged so as to contact a part of the terminal member and a part of the lid portion, respectively, overlap in the first direction, and cover at least a part of the gap between the terminal member and the lid portion. Effect of the Invention
[0008] According to the battery of the embodiment of the present disclosure, the battery element is housed inside the exterior body without the lid and the terminal member overlapping in the first direction, and therefore the secondary battery of the embodiment of the present disclosure can have a high capacity while being thin in shape.
[0009] Note that the effects of the present disclosure are not necessarily limited to the effects described herein, but may be any of a series of effects related to the present technology described below. [Brief description of the drawings]
[0010] [Figure 1A] FIG. 1A is a perspective view illustrating a configuration of a secondary battery according to an embodiment of the present disclosure. [Figure 1B] FIG. 1B is an exploded perspective view of the secondary battery shown in FIG. 1A. [Diagram 2] FIG. 2 is a vertical sectional view showing a sectional configuration of the secondary battery shown in FIG. 1A. [Diagram 3] FIG. 3 is an enlarged cross-sectional view showing a cross-sectional configuration of a portion of the secondary battery shown in FIG. [Figure 4] FIG. 4 is a partial cross-sectional view illustrating the configuration of the battery element shown in FIG. [Figure 5A] FIG. 5A is a first cross-sectional view illustrating a method for manufacturing the secondary battery shown in FIG. 1A. [Figure 5B] FIG. 5B is a second cross-sectional view illustrating the method for manufacturing the secondary battery shown in FIG. 1A. [Figure 5C] FIG. 5C is a third cross-sectional view illustrating the method for manufacturing the secondary battery shown in FIG. 1A. [Figure 5D] FIG. 5D is a fourth cross-sectional view illustrating the method for manufacturing the secondary battery shown in FIG. 1A. [Figure 6] FIG. 6 is a cross-sectional view showing a vertical cross-sectional configuration of a secondary battery according to a first modified example. [Figure 7] FIG. 7 is an enlarged cross-sectional view showing a cross-sectional configuration of a portion of the secondary battery of the second modified example. [Figure 8] FIG. 8 is an enlarged cross-sectional view showing a cross-sectional configuration of a portion of a secondary battery according to a third modified example. [Figure 9] FIG. 9 is an enlarged cross-sectional view showing a cross-sectional configuration of a portion of a secondary battery according to a fourth modified example. [Figure 10] FIG. 10 is an enlarged cross-sectional view illustrating a cross-sectional configuration of a portion of a secondary battery according to a fifth modified example. [Figure 11] FIG. 11 is an enlarged cross-sectional view showing a cross-sectional configuration of a portion of a secondary battery according to a sixth modified example. [Figure 12] FIG. 12 is an enlarged cross-sectional view showing a cross-sectional configuration of a portion of a secondary battery according to a seventh modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The description will be given in the following order. 1. One embodiment 1-1.Configuration 1-2.Operation 1-3. Manufacturing method 1-4. Actions and Effects 2. Modifications of the embodiment 2-1. First modified example 2-2. Second modified example 2-3.Third modified example 2-4.Fourth modified example 2-5. Fifth modified example 2-6. Sixth Modification 2-7. Seventh Variation 3. Other Modifications
[0012] <1. One embodiment> First, a secondary battery according to an embodiment of the present disclosure will be described.
[0013] The secondary battery described here has a flat, columnar, three-dimensional appearance, and is called a coin type or button type. As described later, this secondary battery has a pair of bottoms facing each other and a side wall portion located between the pair of bottoms. In this secondary battery, the height is smaller than the outer diameter. The "outer diameter" here refers to the maximum diameter (maximum outer diameter) of the bottoms. In this secondary battery, the maximum diameters of the pair of opposing bottoms are substantially equal to each other. Also, the "height" here refers to the maximum distance from the upper surface of one bottom to the lower surface of the other bottom. In this embodiment, the direction in which the pair of bottoms face each other is defined as the height direction Z.
[0014] The charge / discharge principle of the secondary battery is not particularly limited, but the following describes a case where the battery capacity is obtained by utilizing the absorption and release of the electrode reactant. This secondary battery includes an electrolyte together with a positive electrode and a negative electrode. In this secondary battery, the charge capacity of the negative electrode is larger than the discharge capacity of the positive electrode in order to prevent the electrode reactant from being deposited on the surface of the negative electrode during charging. That is, the electrochemical capacity per unit area of the negative electrode is set to be larger than the electrochemical capacity per unit area of the positive electrode. The secondary battery of this embodiment is a high-charge voltage secondary battery that can exhibit good cycle characteristics without reducing the energy density even when charging at a high voltage of 4.38V or more.
[0015] The type of the electrode reactant is not particularly limited, but specifically, it is a light metal such as an alkali metal or an alkaline earth metal, etc. The alkali metal is lithium, sodium, potassium, etc., and the alkaline earth metal is beryllium, magnesium, calcium, etc.
[0016] In the following, an example will be given in which the electrode reactant is lithium. A secondary battery that obtains battery capacity by utilizing the absorption and release of lithium is a so-called lithium ion secondary battery. In this lithium ion secondary battery, lithium is absorbed and released in an ionic state.
[0017] (1-1. Composition) Fig. 1A shows a perspective configuration of a secondary battery of this embodiment. Fig. 1B is an exploded perspective view showing the configuration of the secondary battery shown in Fig. 1A. Fig. 2 shows a vertical cross-sectional configuration along the height direction of the secondary battery shown in Fig. 1A. Fig. 3 is a partial cross-sectional view showing an enlarged vertical cross-section of a part of the secondary battery shown in Fig. 2. However, Fig. 3 shows only some of the components of the secondary battery.
[0018] In the following, for convenience, the upper side of each of the pages in FIGS. 1A, 1B and 2 will be described as the upper side of the secondary battery, and the lower side of each of the pages in FIGS. 1A, 1B and 2 will be described as the lower side of the secondary battery.
[0019] The secondary battery described here has a three-dimensional shape with a height H smaller than an outer diameter D, that is, a flat and columnar three-dimensional shape, as shown in FIG. 1A. The three-dimensional shape of the secondary battery shown in FIG. 1A is flat and cylindrical (columnar). In this embodiment, the vertical direction of the paper in each of FIG. 1A, FIG. 1B, and FIG. 2 is defined as the height direction Z. Therefore, the height H means the dimension of the secondary battery of this embodiment in the height direction Z. In addition, the outer diameter D means the dimension of the secondary battery of this embodiment in the direction perpendicular to the height direction Z.
[0020] The dimensions of the secondary battery are not particularly limited, but as an example, the outer diameter D is 3 mm to 30 mm and the height H is 0.5 mm to 70 mm. However, the ratio (D / H) of the outer diameter D to the height H is greater than 1. That is, the outer diameter D is greater than the height H. The upper limit of this ratio (D / H) is not particularly limited, but is preferably 25 or less.
[0021] As shown in FIGS. 1A, 1B, and 2, this secondary battery includes an exterior body 10, a sealing body 30, a battery element 40, a positive electrode lead 51, a negative electrode lead 52, and insulating films 62, 63.
[0022] [Exterior body] As shown in FIGS. 1A, 1B, and 2, the exterior body 10 is a hollow structure having an internal space V for housing the battery element 40 and the like.
[0023] In the configuration example shown in FIG. 1A, the exterior body 10 has a flat and approximately cylindrical outer shape in accordance with the three-dimensional shape of the secondary battery, which is flat and cylindrical. Specifically, the exterior body 10 has a pair of bottoms M1 and M2 facing each other, and a side wall M3 located between the bottoms M1 and M2. That is, the side wall M3 connects the bottoms M1 and M2 and surrounds the battery element 40. The upper end of the side wall M3 is connected to the bottom M1. The lower end of the side wall M3 is connected to the bottom M2. The planar shape of each of the bottoms M1 and M2 is circular. The side wall M3 is a cylindrical member having a circular planar shape.
[0024] The exterior body 10 has a positive electrode terminal plate 11 and a lid portion 12 as a bottom portion M1, and a storage portion 13 as a bottom portion M2 and a side wall portion M3. The storage portion 13 has a cylindrical wall portion 14 and a negative electrode terminal plate 15. The lid portion 12, the cylindrical wall portion 14, and the negative electrode terminal plate 15 are welded to each other to form a battery can 20 (see FIG. 1A). That is, the battery can 20 is a can in which the lid portion 12, the cylindrical wall portion 14, and the negative electrode terminal plate 15, which were physically separated from each other, are welded to each other, and is a so-called welded can. As a result, the battery can 20 after welding is a single member that is physically integrated as a whole, and cannot be separated into the lid portion 12, the cylindrical wall portion 14, and the negative electrode terminal plate 15 after the fact. In addition, each of the lid portion 12, the cylindrical wall portion 14, and the negative electrode terminal plate 15 contains at least one of a plurality of conductive materials, such as metal materials and alloy materials. The conductive material may be, for example, Fe (iron), Cu (copper), Ni (nickel), stainless steel, iron alloy, copper alloy, nickel alloy, etc. The type of stainless steel is not particularly limited, but specifically includes SUS304 and SUS316. The battery can 20 is not limited to one in which the lid portion 12, the cylindrical wall portion 14, and the negative electrode terminal plate 15, which were physically separated from each other, are integrated by welding. The battery can 20 may be one in which at least two of the lid portion 12, the cylindrical wall portion 14, and the negative electrode terminal plate 15 are integrated by, for example, molding one plate-shaped member.
[0025] The lid portion 12 has an annular shape as a whole, and has an opening edge 12K that surrounds the positive electrode terminal plate 11 in a plane perpendicular to the height direction Z. The lid portion 12 surrounds the positive electrode terminal plate 11 without overlapping with the positive electrode terminal plate 11 in a plan view seen from the height direction Z. The positive electrode terminal plate 11 is disposed in the opening of the lid portion 12 defined by the opening edge 12K. The positive electrode terminal plate 11 has an end face 11E that faces the opening edge 12K of the lid portion 12 at a distance. A sealing body 30 is disposed to cover the gap between the opening edge 12K and the end face 11E of the positive electrode terminal plate 11. Therefore, the internal space V of the exterior body 10 is sealed by the positive electrode terminal plate 11, the lid portion 12, the cylindrical wall portion 14, the negative electrode terminal plate 15, and the sealing body 30. In the secondary battery of this embodiment, the battery element 40 is sealed in the internal space V. The lid portion 12 and the positive electrode terminal plate 11 form a bottom portion M1, the negative electrode terminal plate 15 forms a bottom portion M2, and the cylindrical wall portion 14 forms a side wall portion M3. The width W12, which is the dimension in the radial direction R of the lid portion 12, is larger than the width W14, which is the dimension in the radial direction R of the cylindrical wall portion 14.
[0026] An internal space V penetrating in the height direction Z is provided inside the cylindrical wall portion 14. That is, the cylindrical wall portion 14 includes an upper open end 14K1 and a lower open end 14K2 that face each other in the height direction Z. The upper open end 14K1 forms an upper opening as an insertion port through which the battery element 40 can be inserted in the height direction Z. Similarly, the lower open end 14K2 may form a lower opening as an insertion port through which the battery element 40 can be inserted in the height direction Z.
[0027] As shown in FIG. 1A and FIG. 1B, the positive electrode terminal plate 11 is a substantially disk-shaped member that closes the opening of the lid portion 12 together with the sealing body 30. The positive electrode terminal plate 11 includes an outer surface 11S1 extending along a horizontal plane perpendicular to the height direction Z, and an end surface 11E that goes around along the outer edge of the outer surface 11S1. The positive electrode terminal plate 11 is disposed inside the opening of the lid portion 12 defined by the opening edge 12K of the lid portion 12. In this secondary battery, the positive electrode terminal plate 11 is disposed inside the exterior body 10 in the height direction Z relative to the lid portion 12. That is, in the height direction Z, the position of the outer surface 11S1 of the positive electrode terminal plate 11 may be the same as the position of the outer surface 12S1 of the lid portion 12, or may be closer to the internal space V than the position of the outer surface 12S1. In addition, in the height direction Z, the position of the inner surface 11S2 of the positive terminal plate 11 may be the same as the position of the inner surface 12S2 of the lid portion 12, or may be located outside the outer casing 10 relative to the position of the inner surface 12S2. Therefore, the area occupied by the positive terminal plate 11 in the height direction Z may be included in the area occupied by the lid portion 12 in the height direction Z. As shown in FIG. 1A and FIG. 1B, the negative terminal plate 15 is a substantially disk-shaped member that closes the lower opening of the cylindrical wall portion 14. The negative terminal plate 15 is joined to the lower open end 14K2 of the cylindrical wall portion 14 without any gap. The negative terminal plate 15 includes an outer surface 15S1 extending along a horizontal plane perpendicular to the height direction Z, and an end surface 15E that goes around along the outer edge of the outer surface 15S1.
[0028] The positive electrode terminal plate 11 and the negative electrode terminal plate 15 are external connection terminals for connecting to the outside. The positive electrode terminal plate 11 is connected to a positive electrode 41 (described later) of the battery element 40 via a positive electrode lead 51. The negative electrode terminal plate 15 is connected to a negative electrode 42 (described later) of the battery element 40 via a negative electrode lead 52. The positive electrode terminal plate 11 and the negative electrode terminal plate 15 are each a conductive plate-like member made of, for example, a metal material. When using the secondary battery of this embodiment, the positive electrode 41 and the negative electrode 42 are connected to an electronic device via the positive electrode terminal plate 11 and the negative electrode terminal plate 15, respectively. Therefore, the electronic device can operate using the secondary battery as a power source.
[0029] The positive electrode terminal plate 11 includes at least one of a plurality of conductive materials such as metal materials and alloy materials. The conductive materials are aluminum and aluminum alloys. The positive electrode terminal plate 11 may also be a clad material formed by rolling and bonding an aluminum layer to a metal layer made of at least one of Fe (iron), Cu (copper), Ni (nickel), stainless steel, iron alloys, copper alloys, and nickel alloys. More specifically, the positive electrode terminal plate 11 may be a composite member having a three-layer structure of, for example, an Al (aluminum) layer, a stainless steel layer, and a nickel layer. This composite member is disposed so that the Al layer is located on the inside (the inner space V side) of the exterior body 10 and is bonded to the positive electrode lead 51, and the nickel layer is exposed to the outer surface 11S1 of the positive electrode terminal plate 11. The type of stainless steel is not particularly limited, but specifically, it is SUS304, SUS316, and the like.
[0030] The sealing body 30 is a member that contacts and overlaps with each of a part of the positive terminal plate 11 and a part of the lid portion 12 in the height direction Z, and seals the gap G (see FIG. 3, etc.) between the positive terminal plate 11 and the lid portion 12. The width WG of the gap G, that is, the dimension of the gap G in the radial direction R of the secondary battery having a cylindrical shape, is, for example, about 0.5 mm to 1 mm. The width WG of the gap G is, for example, 0.4 or less with respect to the outer diameter D of the secondary battery (WG≦0.4×D). The sealing body 30 covers each of a part of the outer surface 11S1 of the positive terminal plate 11 and a part of the outer surface 12S1 of the lid portion 12. As shown in FIG. 3, the sealing body 30 has a laminated structure including, for example, a base layer 31 and a bonding layer 32. The rigidity of the base layer 31 is preferably higher than the rigidity of the bonding layer 32. The rigidity of the base layer 31 and the bonding layer 32 can be confirmed, for example, by a test such as JIS7171.
[0031] The base layer 31 is, for example, a metal layer. The metal material constituting the metal layer is, for example, stainless steel. The type of stainless steel is not particularly limited, but specific examples include SUS304 and SUS316. In addition, examples of the metal material used for the base layer 31 include simple metals such as aluminum, iron, copper, and nickel, as well as alloys thereof, that is, aluminum alloys, iron alloys, copper alloys, and nickel alloys. The thickness of the base layer 31 can be, for example, 10 μm or more and 200 μm or less.
[0032] The bonding layer 32 has electrical insulation properties. The bonding layer 32 is, for example, a resin adhesive layer. This resin adhesive layer may be made of a thermoplastic resin such as polypropylene (PP) or polyethylene (PE). More specifically, a non-oriented polypropylene (CPP) film is preferable. The thickness of the bonding layer 32 may be, for example, 5 μm or more and 200 μm or less.
[0033] The sealing body 30 may further include an insulating layer 33 laminated on the opposite side of the base layer 31 from the bonding layer 32. The insulating layer 33 may be made of a polyamide resin such as nylon. Alternatively, the insulating layer 33 may be made of polyethylene terephthalate (PET). It is preferable that the insulating layer 33 has a higher heat resistance than the bonding layer 32.
[0034] [Battery element] The battery element 40 is a power generating element that causes charge / discharge reactions to proceed, and is housed in the internal space V of the exterior body 10 as shown in Fig. 1B and Fig. 2. The battery element 40 includes a positive electrode 41 and a negative electrode 42. Here, the battery element 40 further includes a separator 43 and an electrolytic solution (not shown) that is a liquid electrolyte.
[0035] The battery element 40 has a laminated structure in which a positive electrode 41, a separator 43, a negative electrode 42, and a separator 43 are laminated in this order. The lamination direction in the laminated structure of the battery element 40 coincides with the height direction Z of the secondary battery.
[0036] The battery element 40 has a three-dimensional shape that conforms to the three-dimensional shape of the exterior body 10. Specifically, the battery element 40 has a flat and cylindrical three-dimensional shape. Compared to a case in which the battery element 40 has a three-dimensional shape different from the three-dimensional shape of the exterior body 10, when the battery element 40 is housed inside the exterior body 10, so-called dead space, specifically, a gap between the exterior body 10 and the battery element 40, is less likely to occur. Therefore, the internal space of the exterior body 10 is effectively utilized. As a result, the element space volume increases, and the energy density per unit volume of the secondary battery increases.
[0037] (positive electrode) Positive electrode 41 is a first electrode used for promoting charge / discharge reactions, and includes a positive electrode current collector 41A and a positive electrode active material layer 41B, as shown in FIG.
[0038] Positive electrode current collector 41A has a pair of surfaces on which positive electrode active material layer 41B is provided. Positive electrode current collector 41A contains a conductive material such as a metal material, and the metal material is, for example, aluminum.
[0039] The positive electrode active material layer 41B is provided on both sides of the positive electrode current collector 41A, and contains one or more types of positive electrode active materials capable of absorbing and releasing lithium. However, the positive electrode active material layer 41B may be provided on only one side of the positive electrode current collector 41A. The positive electrode active material layer 41B may further contain a positive electrode binder and a positive electrode conductive agent. The method for forming the positive electrode active material layer 41B is not particularly limited, but specifically includes a coating method.
[0040] The positive electrode active material contains a lithium compound. This lithium compound is a general term for compounds containing lithium as a constituent element, and more specifically, a compound containing lithium and one or more transition metal elements as constituent elements. This is because a high energy density can be obtained. However, the lithium compound may further contain one or more of other elements (excluding lithium and transition metal elements). The type of lithium compound is not particularly limited, and specific examples include oxides, phosphate compounds, silicate compounds, and borate compounds. Specific examples of oxides include LiNiO2, LiCoO2, and LiMn2O4, and specific examples of phosphate compounds include LiFePO4 and LiMnPO4.
[0041] The positive electrode binder contains one or more of synthetic rubber and polymer compounds. The synthetic rubber is styrene butadiene rubber and the polymer compounds are polyvinylidene fluoride. The positive electrode conductive agent contains one or more of conductive materials such as carbon materials, and the carbon materials are graphite, carbon black, acetylene black, ketjen black, and the like. However, the conductive materials may be metal materials and polymer compounds.
[0042] (Negative electrode) The negative electrode 42 is a second electrode used for promoting charge / discharge reactions, and includes a negative electrode current collector 42A and a negative electrode active material layer 42B, as shown in FIG.
[0043] The negative electrode current collector 42A has a pair of surfaces on which the negative electrode active material layer 42B is provided. The negative electrode current collector 42A contains a conductive material such as a metal material, and the metal material is, for example, copper.
[0044] The negative electrode active material layer 42B is provided on both sides of the negative electrode current collector 42A, and contains one or more types of negative electrode active materials capable of absorbing and releasing lithium. However, the negative electrode active material layer 42B may be provided on only one side of the negative electrode current collector 42A. The negative electrode active material layer 42B may further contain a negative electrode binder and a negative electrode conductor. Details regarding the negative electrode binder and the negative electrode conductor are the same as those regarding the positive electrode binder and the positive electrode conductor. The method of forming the negative electrode active material layer 42B is not particularly limited, and specifically, it is one or more types of a coating method, a gas phase method, a liquid phase method, a thermal spraying method, a baking method (sintering method), and the like.
[0045] The negative electrode active material contains one or both of a carbon material and a metal-based material. This is because a high energy density can be obtained. Carbon materials include graphitizable carbon, non-graphitizable carbon, and graphite (natural graphite and artificial graphite). The metal-based material is a material that contains, as a constituent element, one or more of metal elements and metalloid elements that can form an alloy with lithium, and the metal elements and metalloid elements are one or both of silicon and tin. However, the metal-based material may be a single element, an alloy, a compound, a mixture of two or more of them, or a material containing two or more of them. Specific examples of metal-based materials are TiSi2 and SiO x (0 <x≦2、または0.2<x<1.4)などである。
[0046] In a plane perpendicular to the height direction Z, the area of the negative electrode 42 is larger than the area of the positive electrode 41. That is, an edge 42T of the negative electrode 42 protrudes outward beyond an edge 41T of the positive electrode 41 in a radial direction R perpendicular to the height direction Z.
[0047] (Separator) The separator 43 is an insulating porous film, and is disposed between the positive electrode 41 and the negative electrode 42, as shown in Fig. 2 and Fig. 4. The separator 43 allows lithium ions to pass through while preventing a short circuit between the positive electrode 41 and the negative electrode 42. The separator 43 contains a polymer compound such as polyethylene.
[0048] In a plane perpendicular to the height direction Z, the area of the separator 43 is preferably larger than each of the areas of the positive electrode 41 and the negative electrode 42. That is, an edge 43T of the separator 43 protrudes outward beyond each of an edge 41T of the positive electrode 41 and an edge 42T of the negative electrode 42 in a radial direction R perpendicular to the height direction Z.
[0049] (electrolyte) The electrolyte is impregnated into each of the positive electrode 41, the negative electrode 42, and the separator 43, and contains a solvent and an electrolyte salt. The solvent contains one or more of non-aqueous solvents (organic solvents) such as carbonate ester compounds, carboxylate ester compounds, and lactone compounds, and the electrolyte containing the non-aqueous solvent is a so-called non-aqueous electrolyte. The electrolyte salt contains one or more of light metal salts such as lithium salt.
[0050] In addition, an insulating film 62 is disposed between the lid portion 12 and the battery element 40. As a result, the lid portion 12 and the battery element 40 are insulated from each other via the insulating film 62, and a short circuit between the lid portion 12 and the positive electrode 41 of the battery element 40 is prevented.
[0051] [Positive lead] As shown in Fig. 2, the positive electrode lead 51 is housed in the internal space V of the exterior body 10. The positive electrode lead 51 is a connection wire electrically connected to each of the positive electrode 41 and the positive electrode terminal plate 11. Therefore, the positive electrode terminal plate 11 (bottom part M1) is electrically connected to the positive electrode 41 via the positive electrode lead 51. The secondary battery shown in Fig. 2 includes one positive electrode lead 51. However, the secondary battery may include two or more positive electrode leads 51.
[0052] The details regarding the material for forming the positive electrode lead 51 are similar to the details regarding the material for forming the positive electrode current collector 41A. However, the materials for forming the positive electrode lead 51 and the positive electrode current collector 41A may be the same as or different from each other.
[0053] The connection position of the positive electrode lead 51 to the positive electrode 41 is not particularly limited and can be set arbitrarily. The positive electrode lead 51 is provided as a separate body from the positive electrode current collector 41A. However, since the positive electrode lead 51 is physically continuous with the positive electrode current collector 41A, it may be integrated with the positive electrode current collector 41A.
[0054] [Negative lead] 2, the negative electrode lead 52 is housed inside the exterior body 10. The negative electrode lead 52 is electrically connected to each of the negative electrode 42 and the negative electrode terminal plate 15. Here, the secondary battery includes one negative electrode lead 52. However, the secondary battery may include two or more negative electrode leads 52.
[0055] The negative electrode lead 52 is connected to the lower end of the negative electrode 42, more specifically, to the lower end of the negative electrode current collector 42A. The negative electrode lead 52 is also connected to the bottom surface of the housing portion 13. The method for connecting the negative electrode lead 52 is not particularly limited, but specifically, it is any one or more of welding methods such as resistance welding and laser welding.
[0056] The details regarding the material for forming the negative electrode lead 52 are similar to the details regarding the material for forming the negative electrode current collector 42A. However, the materials for forming the negative electrode lead 52 and the negative electrode current collector 42A may be the same as or different from each other.
[0057] The negative electrode lead 52 is provided as a separate body from the negative electrode current collector 42A. However, since the negative electrode lead 52 is physically continuous with the negative electrode current collector 42A, the negative electrode lead 52 may be integrated with the negative electrode current collector 42A.
[0058] [Insulating film] 2, the insulating film 62 is an insulating member disposed between the lid portion 12 and the battery element 40 in the height direction Z. The insulating film 62 electrically insulates the battery element 40 from the positive electrode lead 51 and the lid portion 12. The insulating film 62 has a substantially circular planar shape in a plane perpendicular to the height direction Z. The insulating film 62 may be adhered to the lid portion 12 via an adhesive layer.
[0059] Furthermore, the insulating film 62 may contain one or more types of insulating materials such as insulating polymer compounds, etc. The insulating material contained in the insulating film 62 is polyimide, etc.
[0060] 2, the insulating film 63 is an insulating member provided between the negative electrode terminal plate 15, which is the bottom portion M2, and the battery element 40 in the height direction Z. The insulating film 63 electrically insulates the battery element 40 from the negative electrode lead 52 and the bottom portion M2 (negative electrode terminal plate 15).
[0061] The details regarding the material for forming the insulating film 63 are similar to the details regarding the material for forming the insulating film 62. However, the material for forming the insulating film 63 and the material for forming the insulating film 62 may be the same as or different from each other.
[0062] [others] The secondary battery may further include one or more other components.
[0063] Specifically, the secondary battery is provided with a safety valve mechanism. This safety valve mechanism is configured to cut off the electrical connection between the exterior body 10 and the battery element 40 when the internal pressure of the exterior body 10 reaches a certain level or higher. The internal pressure of the exterior body 10 reaches a certain level or higher due to a short circuit occurring inside the secondary battery, the secondary battery being heated from the outside, etc. The location where the safety valve mechanism is installed is not particularly limited, but it is preferable that the safety valve mechanism be provided on either of the bottoms M1 and M2.
[0064] The secondary battery may also include an insulator other than the insulating films 62, 63 between the exterior body 10 and the battery element 40. This insulator includes one or more types of insulating film and insulating sheet, and prevents a short circuit between the exterior body 10 and the battery element 40. The installation range of the insulator is not particularly limited and can be set arbitrarily.
[0065] The exterior body 10 is provided with an open-close valve. This open-close valve breaks when the internal pressure of the exterior body 10 reaches a certain level or higher, thereby releasing the internal pressure. The installation location of the open-close valve is not particularly limited, but is preferably either the bottom M1 or M2, as with the installation location of the safety valve mechanism described above, and more preferably the bottom M2.
[0066] (1-2.Operation) When the secondary battery is charged, in the battery element 40, lithium is released from the positive electrode 41 and the lithium is absorbed in the negative electrode 42 via the electrolyte. On the other hand, when the secondary battery is discharged, in the battery element 40, lithium is released from the negative electrode 42 and the lithium is absorbed in the positive electrode 41 via the electrolyte. During these charge and discharge operations, lithium is absorbed and released in an ionic state.
[0067] (1-3. Manufacturing method) Next, a method for manufacturing a secondary battery according to the present embodiment will be described with reference to FIGS. 5A to 5D in addition to FIGS. 1A to 4.
[0068] 1B, positive terminal plate 11, lid portion 12, cylindrical wall portion 14, and negative terminal plate 15, which are physically separated from one another, are prepared. Next, for example, end face 15E of negative terminal plate 15 is brought into contact with lower open end 14K2 of cylindrical wall portion 14, and the contact point is heated and pressurized to bond end face 15E to lower open end 14K2. This results in housing portion 13 in which cylindrical wall portion 14 and negative terminal plate 15 are joined together.
[0069] [Preparation of positive electrode] First, a positive electrode mixture is prepared by mixing a positive electrode active material, a positive electrode binder, a positive electrode conductive agent, and the like. Next, the prepared positive electrode mixture is poured into an organic solvent or the like to prepare a paste-like positive electrode mixture slurry. Next, the positive electrode mixture slurry is applied to both sides of a positive electrode current collector 41A to form a positive electrode active material layer 41B. Finally, the positive electrode active material layer 41B is compression molded using a roll press or the like. In this case, the positive electrode active material layer 41B may be heated, or the compression molding may be repeated multiple times. In this way, the positive electrode 41 is prepared.
[0070] [Preparation of negative electrode] The negative electrode 42 is produced by the same procedure as that for producing the positive electrode 41. Specifically, a negative electrode mixture obtained by mixing a negative electrode active material, a negative electrode binder, a negative electrode conductive agent, and the like is poured into an organic solvent to prepare a paste-like negative electrode mixture slurry, and then the negative electrode mixture slurry is applied to both sides of a negative electrode current collector 42A to form a negative electrode active material layer 42B. Thereafter, the negative electrode active material layer 42B is compression molded using a roll press or the like. In this way, the negative electrode 42 is produced.
[0071] [Preparation of electrolyte] An electrolyte salt is added to a solvent, whereby the electrolyte salt is dispersed or dissolved in the solvent, and an electrolyte solution is prepared.
[0072] [Secondary battery assembly] First, after preparing the sealing body 30, a part of the sealing body 30 (of the bonding layer 32) is adhered to the peripheral portion of the surface 11S1 of the positive electrode terminal plate 11 as shown in Fig. 5A. Then, another part of the sealing body 30 (of the bonding layer 32) is adhered to the outer surface 12S1 near the opening edge 12K of the lid portion 12 as shown in Fig. 5B.
[0073] Next, using a welding method such as resistance welding, a portion of the positive electrode lead 51 is connected to a portion of the positive electrode 41 (positive electrode current collector 41A), and a portion of the negative electrode lead 52 is connected to a portion of the negative electrode 42 (negative electrode current collector 42A).
[0074] Next, the positive electrode 41 and the negative electrode 42 are laminated with the separator 43 interposed therebetween to obtain a laminated structure. This laminated structure has the same configuration as that of the battery element 40, except that the positive electrode 41, the negative electrode 42, and the separator 43 are not impregnated with an electrolyte solution.
[0075] 5C, the insulating film 63 and the laminated structure to which the positive electrode lead 51 and the negative electrode lead 52 are connected are housed inside the housing portion 13 from the upper open end 14K1 of the cylindrical wall portion 14. At this time, the negative electrode lead 52 is connected to the inner surface 15S2 of the negative electrode terminal plate 15 by using a welding method such as resistance welding. Then, the insulating film 62 is placed on the laminated structure.
[0076] Next, the positive electrode lead 51 is connected to the inner surface 11S2 of the positive electrode terminal plate 11 by using a welding method such as resistance welding, as shown in FIG. 5D.
[0077] Next, the electrolyte is injected into the housing portion 13 from the upper open end 14K1. As a result, the laminated structure including the positive electrode 41, the negative electrode 42, and the separator 43 is impregnated with the electrolyte, and the battery element 40 is produced. Note that the laminated structure may be impregnated with the electrolyte beforehand, before being housed in the housing portion 13.
[0078] Next, the lid portion 12 and the storage portion 13 are overlapped with each other so that the lid portion 12 closes the upper open end 14K1.
[0079] Finally, the inner surface 12S2 of the lid portion 12 is welded to the housing portion 13 using a welding method such as laser welding. As a result, the battery can 20 and the exterior body 10 are formed, and the battery element 40 and the like are housed inside the exterior body 10, completing the assembly of the secondary battery.
[0080] [Stabilization of secondary batteries] The assembled secondary battery is charged and discharged. Various conditions such as the environmental temperature, the number of charge / discharge cycles (number of cycles), and the charge / discharge conditions can be set arbitrarily. As a result, a coating is formed on the surface of the negative electrode 42, etc., and the state of the secondary battery is electrochemically stabilized. Thus, the secondary battery is completed.
[0081] (1-4. Actions and Effects) In this manner, in the secondary battery of this embodiment, the annular lid portion 12 surrounds the positive electrode terminal plate 11 along a plane perpendicular to the height direction Z, and the sealing body 30 overlaps a part of the positive electrode terminal plate 11 and a part of the lid portion 12 in the height direction Z, and seals the gap G between the positive electrode terminal plate 11 and the lid portion 12. That is, the battery element 40 is accommodated inside the exterior body 10 without the positive electrode terminal plate 11 and the lid portion 12 overlapping in the height direction Z. Furthermore, the inside of the secondary battery is sealed by the sealing body 30 provided so as to straddle the gap G. Therefore, according to the secondary battery of this embodiment, it is possible to have a high capacity while having a thin shape as a whole. Furthermore, by providing the sealing body 30, the position of the outer surface 11S1 of the positive electrode terminal plate 11 is lower than the position of the upper surface of the sealing body 30 in the height direction Z. Therefore, it is possible to prevent an unintended short circuit between the positive electrode terminal plate 11 and the battery can 20 via an external conductor.
[0082] In particular, in the secondary battery of the present embodiment, the sealing body 30 has a laminated structure including a base material layer 31 and a bonding layer 32 that bonds each of a portion of the positive electrode terminal plate 11 and a portion of the lid portion 12 to the base material layer 31. For this reason, for example, by forming the bonding layer 32 from a material with excellent adhesiveness and forming the base material layer 31 from a material with higher rigidity than the bonding layer 32, it is possible to ensure both sealing performance and high strength.
[0083] In the secondary battery of the present embodiment, the position of the inner surface 11S2 of the positive terminal plate 11 and the position of the inner surface 12S2 of the lid portion 12 substantially coincide with each other in the height direction Z, so that the battery element 40 can occupy the internal space V of the exterior body 10 without waste. Therefore, higher capacity efficiency can be obtained.
[0084] In addition, in the secondary battery of the present embodiment, since the exterior body 10 has a cylindrical outer shape, it can have higher mechanical strength compared to, for example, a case in which the exterior member has a prismatic or elliptical cylindrical outer shape. However, the secondary battery of the present disclosure also includes a case in which the exterior member has a prismatic or elliptical cylindrical outer shape.
[0085] Furthermore, if the secondary battery is a lithium ion secondary battery, sufficient battery capacity can be stably obtained by utilizing the absorption and release of lithium.
[0086] 2. Modifications of the embodiment (2-1. First modified example) Next, a secondary battery as a first modified example of an embodiment of the present disclosure will be described with reference to FIG. 6. FIG. 6 is a cross-sectional view showing a secondary battery as a first modified example, and corresponds to FIG. 2 showing the secondary battery of the above embodiment. In the secondary battery of the above embodiment, the case where the outer diameter of the lid portion 12 is substantially equal to the outer diameter of the cylindrical wall portion 14 constituting the side wall portion M3 is illustrated. That is, in the secondary battery of the above embodiment, the outer diameter of the lid portion 12 and the outer diameter of the cylindrical wall portion 14 are both equal to the outer diameter D of the secondary battery. In contrast, in the secondary battery of the first modified example, the outer diameter of the lid portion 12 is larger than the outer diameter of the cylindrical wall portion 14. Except for this point, the configuration of the secondary battery of the first modified example is substantially the same as the configuration of the secondary battery of the above embodiment. In the secondary battery of the first modified example, the inner diameter of the lid portion 12, i.e., the diameter of the opening edge 12K may be substantially equal to the inner diameter of the cylindrical wall portion 14. The secondary battery of the first modified example can also be expected to have the same effect as the secondary battery of the above embodiment.
[0087] In the secondary battery of the first modified example, the lid portion 12 and the cylindrical wall portion 14 may be integrally formed. Alternatively, the lid portion 12 and the cylindrical wall portion 14 may be formed as separate bodies and connected to each other.
[0088] (2-2. Second Modification) Next, a secondary battery as a second modified example of an embodiment of the present disclosure will be described with reference to FIG. 7. FIG. 7 is a partial cross-sectional view showing an enlarged portion of the secondary battery as the second modified example, and corresponds to FIG. 3 which is a partial cross-sectional view showing an enlarged portion of the secondary battery of the embodiment. As shown in FIG. 7, the secondary battery of the second modified example further has a resin layer 16. Except for this, the configuration of the secondary battery of the second modified example is substantially the same as the configuration of the secondary battery of the embodiment. The resin layer 16 is provided so as to fill at least a part of the gap G between the positive electrode terminal plate 11 and the lid portion 12. In the example shown in FIG. 7, the resin layer 16 fills only a part of the gap G, but the resin layer 16 may be filled so as to fill the entire gap G.
[0089] According to the secondary battery of the second modified example, since the gap G is further provided with the resin layer 16, the mechanical strength can be improved compared to the secondary battery of the above embodiment. For example, the resistance to stress unintentionally applied from the outside is improved, and a highly reliable secondary battery is realized.
[0090] (2-3. Third Modification) Next, a secondary battery as a third modified example of an embodiment of the present disclosure will be described with reference to FIG. 8. FIG. 8 is a partial cross-sectional view showing an enlarged portion of the secondary battery as the third modified example, and corresponds to FIG. 3 which is a partial cross-sectional view showing an enlarged portion of the secondary battery of the embodiment. As shown in FIG. 8, the secondary battery of the third modified example further has a sealing body 17 in addition to the resin layer 16. Except for this point, the configuration of the secondary battery of the third modified example is substantially the same as the configuration of the secondary battery of the second modified example of the embodiment. The sealing body 17 covers each of a part of the inner surface 11S2 of the positive electrode terminal plate 11 and a part of the inner surface 12S2 of the lid portion 12, and seals the gap G. As shown in FIG. 8, the sealing body 17 has a laminated structure including, for example, a base layer 17A and a bonding layer 17B. The rigidity of the base layer 17A is preferably higher than the rigidity of the bonding layer 17B. The base layer 17A is, for example, a metal layer. The metal material constituting the metal layer is, for example, the same as that of the base layer 31. The bonding layer 17B has electrical insulation properties. The constituent material of the bonding layer 17B is, for example, the same as the constituent material of the bonding layer 32. Therefore, it is preferable that the rigidity of the base layer 17A is higher than the rigidity of the bonding layer 17B.
[0091] The secondary battery of the third modified example further includes sealing body 17 that seals gap G, and therefore the mechanical strength can be further improved compared to the secondary battery of the second modified example. For example, the resistance to stress unintentionally applied from the outside is further increased, and a secondary battery with even higher reliability is realized.
[0092] (2-4. Fourth Modification) Next, a secondary battery as a fourth modified example of an embodiment of the present disclosure will be described with reference to FIG. 9. FIG. 9 is a partial cross-sectional view showing an enlarged portion of a secondary battery as a fourth modified example, and corresponds to FIG. 3 which is a partial cross-sectional view showing an enlarged portion of the secondary battery of the embodiment. As shown in FIG. 9, the secondary battery of the fourth modified example may further include a sealing body 17 without providing a resin layer 16. Except for this, the configuration of the secondary battery of the fourth modified example is substantially the same as the configuration of the secondary battery of the second modified example shown in FIG. 7. The configuration of the sealing body 17 is the same as the sealing body 17 of the secondary battery as the third modified example shown in FIG. 8.
[0093] (2-5. Fifth Modification) 10 is a partial cross-sectional view showing an enlarged portion of a secondary battery as a fifth modified example, and corresponds to FIG. 3 which is a partial cross-sectional view showing an enlarged portion of the secondary battery of the above-described embodiment. In the secondary battery of the fifth modified example, as shown in FIG. 10, a part of the bonding layer 32 of the sealing body 30 and a part of the bonding layer 17B of the sealing body 17 are bonded inside the gap G. Except for this point, the configuration of the secondary battery of the fifth modified example is substantially the same as the configuration of the secondary battery of the fourth modified example shown in FIG.
[0094] According to the secondary battery of the fifth modified example, a portion of the sealing body 30 and a portion of the sealing body 17 are joined to each other inside the gap G, so that the mechanical strength can be further improved compared to the secondary battery of the fourth modified example.
[0095] (2-6. Sixth Modification) Fig. 11 is an exploded perspective view showing the configuration of a secondary battery as a sixth modified example of an embodiment, and corresponds to Fig. 1B which is an exploded perspective view of the secondary battery of the above-mentioned embodiment. In the secondary battery of the sixth modified example, as shown in Fig. 11, the battery element 40 has a wound structure. Except for this point, the configuration of the secondary battery of the sixth modified example is substantially the same as the configuration of the secondary battery of the embodiment shown in Fig. 1B.
[0096] (2-7. Seventh Modification) FIG. 12 is a partial cross-sectional view showing an enlarged view of a secondary battery as a seventh modified example of an embodiment of the present disclosure, and corresponds to FIG. 3 which is a partial cross-sectional view showing an enlarged view of a part of the secondary battery of the embodiment. In the secondary battery of the embodiment (FIG. 3), the width W12, which is the dimension in the radial direction R of the lid portion 12, is larger than the width W14, which is the dimension in the radial direction R of the cylindrical wall portion 14. In contrast, in the secondary battery of the seventh modified example, as shown in FIG. 12, the width W12 in the radial direction R of the lid portion 12 is equal to or smaller than the width W14 in the radial direction R of the cylindrical wall portion 14. Therefore, the area of the positive electrode terminal plate 11 can be made larger in the plane direction perpendicular to the height direction Z. However, the joint area between the sealing body 30 and the outer surface 12S1 of the lid portion 12 is smaller than that of the secondary battery of the embodiment (FIG. 3). Therefore, the mechanical strength of the secondary battery of the embodiment (FIG. 3) is higher than that of the secondary battery of the seventh modified example (FIG. 12).
[0097] <3. One embodiment> The present disclosure has been described above with reference to one embodiment and several modified examples. However, the configuration of the present technology is not limited to the configurations described in the one embodiment and several modified examples, and can be modified in various ways.
[0098] Specifically, the exterior member has a cylindrical outer shape, but the present disclosure is not limited thereto. For example, the secondary battery may have an exterior member having a prismatic or elliptical outer shape. In the case of a prismatic exterior member, the corners may be rounded.
[0099] In the above embodiment, the electrode reactant is lithium, but the electrode reactant is not particularly limited. Therefore, the electrode reactant may be other alkali metals such as sodium and potassium, or alkaline earth metals such as beryllium, magnesium, and calcium, as described above. In addition, the electrode reactant may be other light metals such as aluminum.
[0100] Furthermore, while a secondary battery has been exemplified in the above embodiment, the battery of the present disclosure is not limited to a secondary battery and may be a primary battery.
[0101] Furthermore, in the above embodiment, a battery having an electrolytic solution that is a liquid electrolyte has been exemplified, but the battery of the present disclosure may be an all-solid-state battery that includes a solid electrolyte.
[0102] The effects described in this specification are merely examples, and the effects of the present disclosure are not limited to the effects described in this specification. Therefore, other effects may be obtained with respect to the present disclosure.
[0103] Furthermore, the present disclosure may take the following aspects. <1> A battery element; an exterior body having a first bottom, a second bottom facing the first bottom in a first direction, and a sidewall portion located between the first bottom and the second bottom and surrounding the battery element; The encapsulant and Equipped with The exterior body is the first bottom portion includes a terminal member that is disposed adjacent to the battery element in the first direction and is connected to the battery element, and an annular lid portion that is spaced apart from the terminal member and surrounds the terminal member without overlapping with the terminal member in a plan view seen in the first direction, the second bottom and the side wall include a housing portion joined to the lid portion and housing the battery element; The sealing body is a first insulating layer disposed in contact with a portion of the terminal member and a portion of the lid portion, overlapping the first insulating layer in the first direction, and covering at least a portion of the gap between the terminal member and the lid portion; battery. <2> The terminal member is disposed on an inner side of the exterior body relative to the lid portion in the first direction. the above <1> Battery as described. <3> The lid portion has an opening, The terminal member is disposed inside the opening. the above <1> or <2> 2. The battery according to claim 1 . <4> An area occupied by the terminal member in the first direction is included in an area occupied by the cover portion in the first direction. the above <1> from <3> 2. A battery according to claim 1 . <5> The terminal member and the cover portion are filled with a resin. the above <1> from <4> 2. A battery according to claim 1 . <6> The sealing body covers a part of the outer surface of the terminal member and a part of the outer surface of the cover. the above <1> from <5> 2. A battery according to claim 1 . <7> The terminal member further includes an additional seal that covers a part of the inner surface of the terminal member and a part of the inner surface of the cover and seals the gap. the above <1> from <6> 2. A battery according to claim 1 . <8> The sealing body has a laminated structure including a base layer and a bonding layer that bonds a portion of the terminal member and a portion of the lid portion to the base layer. the above <1> from <7> 2. A battery according to claim 1 . <9> The rigidity of the base layer is higher than the rigidity of the bonding layer. the above <8> 2. The battery according to claim 1 . <10> The base layer is a metal layer, and the bonding layer is a resin adhesive layer. the above <9> 2. The battery according to claim 1 . [Explanation of symbols]
[0104] 10...Exterior body, M1,M2...bottom, M3...side wall, 11...positive terminal plate, 11E...end surface, 11S1...outer surface, 12...lid, 12K...opening edge, 12S1...outer surface Surface, 12S2...Inner surface, 13...Accommodation part, 14...Cylindrical wall part, 14K1...Upper open end, 14K2...Lower open end, 14S...Inner wall surface, 15...Negative electrode terminal plate, 16...Resin layer , 17...sealing body, 20...battery can, 30...sealing body, 31...substrate layer, 32...bonding layer, 33...insulating layer, 40...battery element, 41...positive electrode, 41A...positive electrode current collector, 41B...positive electrode active material layer, 42...negative electrode, 42A...negative electrode current collector, 42B...negative electrode active material layer, 51...positive electrode lead, 52...negative electrode lead, 62, 63...insulating film, V...internal space.
Claims
1. A battery element; an exterior body having a first bottom, a second bottom facing the first bottom in a first direction, and a sidewall portion located between the first bottom and the second bottom and surrounding the battery element; The encapsulant and Equipped with The exterior body is the first bottom portion includes a terminal member disposed adjacent to the battery element in the first direction and connected to the battery element, and an annular lid portion spaced apart from the terminal member and surrounding the terminal member without overlapping with the terminal member in a plan view seen in the first direction; the second bottom portion and the side wall portion include a housing portion joined to the lid portion and housing the battery element; The sealing body is a first insulating layer disposed in the first direction so as to contact and overlap a portion of the terminal member and a portion of the lid portion and to cover at least a portion of the gap between the terminal member and the lid portion; battery.
2. The terminal member is disposed on an inner side of the exterior body relative to the lid portion in the first direction. The battery of claim 1.
3. The lid portion has an opening, The terminal member is disposed inside the opening. The battery of claim 1.
4. An area occupied by the terminal member in the first direction is included in an area occupied by the cover portion in the first direction. The battery of claim 1.
5. The sealing body seals a gap between the terminal member and the lid portion.
10. The battery of claim 1.
6. The terminal member and the cover portion are filled with a resin. The battery of claim 1.
7. The sealing body covers a part of the outer surface of the terminal member and a part of the outer surface of the cover. The battery of claim 1.
8. The terminal member further includes an additional seal that covers a part of the inner surface of the terminal member and a part of the inner surface of the cover and seals the gap. The battery of claim 1.
9. The sealing body has a laminated structure including a base layer and a bonding layer that bonds a portion of the terminal member and a portion of the lid portion to the base layer. The battery of claim 1.
10. The rigidity of the base layer is higher than the rigidity of the bonding layer. The battery of claim 9.
11. The base layer is a metal layer, and the bonding layer is a resin adhesive layer. The battery of claim 10.