WO2024116623A1 - 電池 - Google Patents

電池 Download PDF

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Publication number
WO2024116623A1
WO2024116623A1 PCT/JP2023/037465 JP2023037465W WO2024116623A1 WO 2024116623 A1 WO2024116623 A1 WO 2024116623A1 JP 2023037465 W JP2023037465 W JP 2023037465W WO 2024116623 A1 WO2024116623 A1 WO 2024116623A1
Authority
WO
WIPO (PCT)
Prior art keywords
positive electrode
electrode lead
external terminal
negative electrode
battery
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2023/037465
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
彩 増子
公也 矢野
剛 山元
正博 大塚
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Murata Manufacturing Co Ltd
Original Assignee
Murata Manufacturing Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Murata Manufacturing Co Ltd filed Critical Murata Manufacturing Co Ltd
Priority to DE112023005022.8T priority Critical patent/DE112023005022T5/de
Priority to JP2024561230A priority patent/JP7800729B2/ja
Publication of WO2024116623A1 publication Critical patent/WO2024116623A1/ja
Priority to US19/080,286 priority patent/US20250210826A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/533—Electrode connections inside a battery casing characterised by the shape of the leads or tabs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/107—Primary casings; Jackets or wrappings characterised by their shape or physical structure having curved cross-section, e.g. round or elliptic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/109—Primary casings; Jackets or wrappings characterised by their shape or physical structure of button or coin shape
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/131—Primary casings; Jackets or wrappings characterised by physical properties, e.g. gas permeability, size or heat resistance
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • H01M50/148—Lids or covers characterised by their shape
    • H01M50/153—Lids or covers characterised by their shape for button or coin cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
    • H01M50/169—Lids or covers characterised by the methods of assembling casings with lids by welding, brazing or soldering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/172—Arrangements of electric connectors penetrating the casing
    • H01M50/174—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells
    • H01M50/181—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells for button or coin cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/183—Sealing members
    • H01M50/186—Sealing members characterised by the disposition of the sealing members
    • H01M50/188—Sealing members characterised by the disposition of the sealing members the sealing members being arranged between the lid and terminal
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/528—Fixed electrical connections, i.e. not intended for disconnection
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/547—Terminals characterised by the disposition of the terminals on the cells
    • H01M50/548—Terminals characterised by the disposition of the terminals on the cells on opposite sides of the cell
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/552—Terminals characterised by their shape
    • H01M50/553—Terminals adapted for prismatic, pouch or rectangular cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/552—Terminals characterised by their shape
    • H01M50/559—Terminals adapted for cells having curved cross-section, e.g. round, elliptic or button cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/564—Terminals characterised by their manufacturing process
    • H01M50/566—Terminals characterised by their manufacturing process by welding, soldering or brazing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • This disclosure relates to batteries.
  • secondary batteries are being developed as power sources that are small, lightweight, and capable of achieving 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 these secondary batteries (see, for example, Patent Document 1).
  • Patent Document 1 describes a sealed electricity storage device that includes an electrode body 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.
  • a battery according to one embodiment of the present disclosure comprises a battery element including a first electrode and a second electrode, an exterior member housing the battery element, an external terminal attached to the exterior member via an insulating member, a first electrode lead connecting the first electrode to the inner surface of the external terminal, and a second electrode lead connecting the second electrode to the inner surface of the exterior member.
  • At least one of the first electrode lead and the second electrode lead has a first end, a central portion, and a second end, in that order, along a width direction perpendicular to its longitudinal direction, and the central portion is flat and welded to the inner surface of the external terminal or the inner surface of the exterior member. At least one of the first end and the second end is bent in a direction away from the inner surface of the external terminal or the inner surface of the exterior member.
  • At least one of the first end and the second end of at least one of the first electrode lead and the second electrode lead is bent in a direction away from the inner surface of the external terminal or the inner surface of the exterior member. Therefore, the battery of one embodiment of the present disclosure has higher reliability.
  • FIG. 1 is a perspective view illustrating a configuration of a secondary battery according to an embodiment of the present disclosure.
  • FIG. 2 is a cross-sectional view showing the configuration of the secondary battery shown in FIG.
  • FIG. 3 is a partial cross-sectional view showing the configuration of the battery element shown in FIG.
  • FIG. 4A is a plan view illustrating the configuration of the positive electrode lead shown in FIG.
  • FIG. 4B is a first cross-sectional view showing the configuration of the positive electrode lead shown in FIG.
  • FIG. 4C is a second cross-sectional view showing the configuration of the positive electrode lead shown in FIG.
  • FIG. 5A is a plan view illustrating the configuration of the negative electrode lead shown in FIG.
  • FIG. 5B is a first cross-sectional view showing the configuration of the negative electrode lead shown in FIG.
  • FIG. 5C is a second cross-sectional view showing the configuration of the negative electrode lead shown in FIG.
  • FIG. 6 is a perspective view showing the structure of an exterior can used in the manufacturing process
  • the secondary battery described here has a flat, columnar, three-dimensional shape, and is known as a coin type or button type. As described below, this secondary battery has a pair of bottoms that face 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.
  • 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.
  • the principle of charging and discharging a secondary battery is not particularly limited, but the following describes a case where battery capacity is obtained by utilizing the absorption and release of an electrode reactant.
  • This secondary battery has a positive electrode, a negative electrode, and an electrolyte.
  • the charge capacity of the negative electrode is larger than the discharge capacity of the positive electrode to prevent the electrode reactant from being deposited on the surface of the negative electrode during charging.
  • 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 4.38 V or more.
  • the type of electrode reactant is not particularly limited, but specifically, it is a light metal such as an alkali metal or an alkaline earth metal.
  • Alkaline metals include lithium, sodium, and potassium, while alkaline earth metals include beryllium, magnesium, and calcium.
  • the electrode reactant is lithium.
  • a secondary battery that obtains battery capacity by utilizing the absorption and release of lithium is known as a lithium-ion secondary battery.
  • lithium-ion secondary battery lithium is absorbed and released in an ionic state.
  • Fig. 1 shows a perspective configuration of a secondary battery.
  • Fig. 2 shows a cross-sectional configuration of the secondary battery shown in Fig. 1.
  • Fig. 3 shows a cross-sectional configuration of a battery element 40 shown in Fig. 2. However, in Fig. 3, only a part of the cross-sectional configuration of the battery element 40 is enlarged.
  • the secondary battery described here has a three-dimensional shape with a height H smaller than the outer diameter D, that is, a flat and columnar three-dimensional shape, as shown in FIG. 1.
  • the three-dimensional shape of the secondary battery is flat and cylindrical.
  • the vertical direction of the paper in each of FIG. 1 and FIG. 2 is defined as the height direction Z. Therefore, the height H means the dimension in the height direction Z of the secondary battery of this embodiment.
  • the outer diameter D means the dimension in the direction perpendicular to the height direction Z of the secondary battery of this embodiment.
  • 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 of the outer diameter D to the height H (D/H) is greater than 1. In other words, the outer diameter D is greater than the height H.
  • the upper limit of this ratio (D/H) is not particularly limited, but it is preferable that it be 25 or less.
  • this secondary battery includes an outer can 10, an external terminal 20, a battery element 40, and a positive electrode lead 51.
  • the secondary battery further includes a gasket 30, a negative electrode lead 52, a sealant 61, and insulating films 62 and 63.
  • the exterior can 10 is a hollow exterior member that houses the battery element 40 and the like.
  • the exterior can 10 is made of a conductive material.
  • the exterior can 10 has a flat, approximately cylindrical three-dimensional shape in accordance with the three-dimensional shape of the secondary battery, which is flat and cylindrical. Therefore, the exterior can 10 has a pair of bottoms M1, M2 facing each other, and a side wall M3 located between the bottoms M1, 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. As described above, the exterior can 10 is approximately cylindrical.
  • the planar shape of each of the bottoms M1, M2 is circular, and the surface of the side wall M3 is a convex curved surface.
  • the outer can 10 also includes a storage section 11 and a lid section 12 that are welded together. That is, the internal space of the outer can 10 is sealed by welding the lid section 12 to the storage section 11.
  • the bottom section M1 forms the lid section 12, and the bottom section M2 and the side wall section M3 are integrated to form the storage section 11. Therefore, the outer edge of the lid section 12 is welded to the upper end section of the side wall section M3.
  • the storage section 11 is a flat, cylindrical storage member that stores the battery element 40 and other items inside.
  • the storage section 11 has a hollow structure with an open upper end and a closed lower end.
  • the storage section 11 has an opening 11K (Figure 2) at the upper end as an insertion port through which the battery element 40 can be inserted in the height direction Z.
  • the lid 12 is a generally disk-shaped lid member that closes the opening 11K of the storage section 11, and has a through hole 12K.
  • the through hole 12K is used as a connection path for connecting the battery element 40 and the external terminal 20 to each other.
  • the lid 12 is welded to the storage section 11 at the opening 11K.
  • the external terminal 20 is attached to the lid 12 via a gasket 30. That is, the lid 12 supports the external terminal 20 via the gasket 30.
  • the external terminal 20 is attached to the lid 12 via the gasket 30 so as to overlap with the through hole 12K and close the through hole 12K.
  • the external terminal 20 is electrically insulated from the outer can 10.
  • the lid portion 12 is welded to the storage portion 11. As described above, the opening 11K is blocked by the lid portion 12. Therefore, even if one looks at the exterior of the secondary battery, it is considered impossible to determine whether the storage portion 11 had an opening 11K or not.
  • weld marks remain on the surface of the outer can 10, more specifically, at the boundary between the storage section 11 and the lid 12. Based on the presence or absence of the weld marks, it is possible to confirm after the fact whether or not the storage section 11 had an opening 11K.
  • the lid portion 12 is bent so as to partially protrude in the height direction Z toward the inside of the storage portion 11, forming a recessed portion 12H. That is, when viewed from the outside of the outer can 10, the lid portion 12 has a shape that is partially recessed in the height direction Z toward the battery element 40 housed inside the outer can 10.
  • the recessed portion 12H includes a through hole 12K that penetrates in the height direction Z, a bottom portion 12HB that surrounds the through hole 12K along a horizontal plane perpendicular to the height direction Z, and a wall portion 12HW that stands along the outer edge of the bottom portion 12HB.
  • the portion of the lid 12 other than the recess 12H is the peripheral portion 12R.
  • the peripheral portion 12R is annular and surrounds the recess 12H in a horizontal plane perpendicular to the height direction Z of the secondary battery.
  • the peripheral portion 12R surrounds the periphery of the recess 12H and protrudes away from the battery element 40 along the height direction Z. Therefore, in the height direction Z, the surface 12HS of the bottom 12HB of the recess 12H is located lower toward the inside of the storage section 11 than the surface 12RS of the peripheral portion 12R. In other words, in the height direction Z, the distance between the surface 12HS of the bottom 12HB of the recess 12H and the battery element 40 is shorter than the distance between the surface 12RS of the peripheral portion 12R and the battery element 40.
  • the planar shape of the recess 12H i.e., the shape defined by the outer edge of the recess 12H when the secondary battery is viewed from above, is not particularly limited.
  • the planar shape of the recess 12H is approximately circular.
  • the inner diameter and depth of the recess 12H are not particularly limited and can be set arbitrarily. However, the depth of the recess 12H is set so that when the external terminal 20 is attached to the recess 12H via the gasket 30, the height position of the surface 20S of the external terminal 20 is lower than the height position of the surface 12RS of the peripheral portion 12R.
  • the exterior can 10 is a can in which the storage section 11 and the lid section 12, which were previously physically separate, have been welded together, making it a so-called welded can.
  • the exterior can 10 is a single, physically integrated member, and therefore cannot be separated into the storage section 11 and the lid section 12 later.
  • the exterior can 10 which is a welded can, is different from a crimp can formed using a crimping process and is a so-called crimpless can. This is because the element space volume increases inside the exterior can 10, and the energy density per unit volume increases.
  • This "element space volume” refers to the volume (effective volume) of the internal space of the exterior can 10 that can be used to store the battery element 40.
  • the exterior can 10 which is a welded can, does not have any parts that are folded over each other, nor does it have any parts where two or more members overlap each other.
  • Having no overlapping parts means that no parts of the exterior can 10 have been processed (folded) so that they overlap one another. Also, “having no parts where two or more components overlap one another” means that after the secondary battery is completed, the exterior can 10 is physically one component, and therefore the exterior can 10 cannot be separated into two or more components later. In other words, the state of the exterior can 10 in the completed secondary battery is not in a state where two or more components are combined together while overlapping one another so that they can be separated later.
  • the outer can 10 is conductive. More specifically, both the storage section 11 and the lid section 12 are conductive.
  • the outer can 10 is electrically connected to the negative electrode 42 of the battery element 40 via the negative electrode lead 52. Therefore, the outer can 10 also serves as an external connection terminal for the negative electrode 42. Since the secondary battery of this embodiment does not need to have an external connection terminal for the negative electrode 42 separate from the outer can 10, a reduction in the element space volume caused by the presence of the external connection terminal for the negative electrode 42 is suppressed. This increases the element space volume, and therefore increases the energy density per unit volume.
  • the exterior can 10 is a metal can containing one or more types of conductive materials such as metal materials and alloy materials.
  • the conductive materials constituting the metal can include iron, copper, nickel, stainless steel, iron alloys, copper alloys, and nickel alloys.
  • the type of stainless steel is not particularly limited, but specific examples include SUS304 and SUS316.
  • the material forming the storage section 11 and the material forming the lid section 12 may be the same as or different from each other.
  • the lid 12 is insulated via a gasket 30 from the external terminal 20, which serves as the external connection terminal for the positive electrode 41. This is to prevent contact, i.e., a short circuit, between the exterior can 10, which serves as the external connection terminal for the negative electrode 42, and the external terminal 20, which serves as the external connection terminal for the positive electrode 41.
  • the external terminal 20 is a connection terminal that is connected to an electronic device when the secondary battery is mounted on the electronic device. As described above, the external terminal 20 is attached to and supported by the lid portion 12 of the exterior can 10. The external terminal 20 is provided on the opposite side of the bottom portion M2 as viewed from the lid portion 12, at a position overlapping with the through hole 12K in the height direction Z.
  • the external terminal 20 is connected to the positive electrode 41 of the battery element 40 via the positive electrode lead 51. Therefore, the external terminal 20 functions as an external connection terminal for the positive electrode 41.
  • the secondary battery is connected to an electronic device via the external terminal 20 (external connection terminal for the positive electrode 41) and the outer casing 10 (external connection terminal for the negative electrode 42). Therefore, the electronic device can operate using the secondary battery as a power source.
  • the external terminal 20 is a flat, approximately plate-like member that spreads along a horizontal plane perpendicular to the height direction Z of the secondary battery, and is disposed inside the recessed portion 12H via the gasket 30.
  • the external terminal 20 is insulated from the lid portion 12 via the gasket 30.
  • the position of the surface 20FS of the external terminal 20 is lower toward the battery element 40 than the position of the surface 12RS of the peripheral portion 12R of the outer can 10. That is, the external terminal 20 is stored inside the recessed portion 12H so that the surface 20FS, which is the upper end thereof, is recessed toward the battery element 40 more than the surface 12RS.
  • the height of the secondary battery is smaller than when the external terminal 20 protrudes above the lid portion 12. Therefore, the energy density per unit volume of the secondary battery is increased. In addition, it is possible to prevent a short circuit between the outer can 10 and the external terminal 20 via another conductive member.
  • the peripheral portion of the external terminal 20 overlaps with the bottom portion 12HB of the recessed portion 12H in the height direction Z. By having an overlapping portion between the external terminal 20 and the lid portion 12, the mechanical strength of the secondary battery as a whole can be improved.
  • the length of the overlapping portion between the external terminal 20 and the peripheral portion along a horizontal plane perpendicular to the height direction Z is preferably greater than the thickness of the external terminal 20 and greater than the thickness of the bottom portion 12HB.
  • the outer diameter of the external terminal 20 is smaller than the inner diameter of the recess 12H. Therefore, the outer edge 20T of the external terminal 20 is separated from the lid 12.
  • the gasket 30 is disposed only in a part of the area between the external terminal 20 and the lid 12 (recess 12H). More specifically, the gasket 30 is disposed only in a place where the external terminal 20 and the lid 12 would come into contact with each other if the gasket 30 was not present. However, it is preferable that the gasket 30 is also disposed between the inner wall surface of the wall 12HW of the recess 12H and the outer edge 20T of the external terminal 20. It is also preferable that the lid 12 and the external terminal 20 are fixed by the gasket 30.
  • the external terminal 20 also includes one or more types of conductive materials such as metal materials and alloy materials, and the conductive materials are aluminum and aluminum alloys.
  • the external terminal 20 may be formed from a clad material.
  • This clad material includes an aluminum layer and a nickel layer, in that order from the side closest to the gasket 30, and in the clad material, the aluminum layer and the nickel layer are roll-bonded to each other.
  • the gasket 30 is an insulating member disposed between the exterior can 10 (lid portion 12) and the external terminal 20.
  • the external terminal 20 is fixed to the lid portion 12 via the gasket 30.
  • the gasket 30 has a ring-like planar shape having a through hole at a position corresponding to the through hole 12K.
  • the gasket 30 contains one or more types of insulating materials such as insulating polymer compounds, and the insulating materials are resins such as polypropylene and polyethylene.
  • the installation range of the gasket 30 is not particularly limited and can be set arbitrarily.
  • the gasket 30 is placed in the gap between the upper surface of the lid 12 and the lower surface of the external terminal 20 inside the recess 12H.
  • the gasket 30 is also provided between the inner wall surface of the wall 12HW of the recess 12H and the outer edge 20T of the external terminal 20. It is also preferable that the lid 12 and the external terminal 20 are fixed together by the gasket 30.
  • the battery element 40 is a power generating element that causes charge/discharge reactions to proceed, and is housed inside the exterior can 10.
  • the battery element 40 includes a positive electrode 41 and a negative electrode 42.
  • the battery element 40 further includes a separator 43 and an electrolytic solution (not shown) that is a liquid electrolyte.
  • the center line PC shown in FIG. 2 is a line segment that corresponds to the center of the battery element 40 in the direction along the outer diameter D of the secondary battery (outer can 10). In other words, the position P0 of the center line PC corresponds to the position of the center of the battery element 40.
  • the battery element 40 is a so-called wound electrode body. That is, in the battery element 40, the positive electrode 41 and the negative electrode 42 are stacked on top of each other with a separator 43 between them. Furthermore, as shown in FIG. 2, the stacked positive electrode 41, negative electrode 42, and separator 43 are wound around the center line PC as the winding axis. The positive electrode 41 and the negative electrode 42 are wound while maintaining a state in which they face each other with the separator 43 between them. Therefore, a winding center space 40K is formed in the center of the battery element 40.
  • the positive electrode 41, the negative electrode 42, and the separator 43 are wound so that the separator 43 is disposed at the outermost circumference and the innermost circumference of the wound electrode body.
  • the number of windings of the positive electrode 41, the negative electrode 42, and the separator 43 is not particularly limited and can be set arbitrarily.
  • the negative electrode 42 is disposed outside the positive electrode 41 at the outermost circumference of the battery element 40. That is, the outermost positive electrode portion located at the outermost circumference of the positive electrode 41 included in the battery element 40 is disposed inside the outermost negative electrode portion located at the outermost circumference of the negative electrode 42 included in the battery element 40.
  • the outermost positive electrode portion is the outermost portion of the positive electrode 41 in the battery element 40.
  • the outermost negative electrode portion is the outermost portion of the negative electrode 42 in the battery element 40.
  • the negative electrode 42 is disposed inside the positive electrode 41 at the innermost circumference of the battery element 40. That is, the negative electrode innermost circumferential portion located at the innermost periphery of the negative electrode 42 included in the battery element 40 may be located inside the positive electrode innermost circumferential portion located at the innermost periphery of the positive electrode 41 included in the battery element 40.
  • the positive electrode innermost circumferential portion is the innermost part of the positive electrode 41 in the battery element 40.
  • the negative electrode innermost circumferential portion is the innermost part of the negative electrode 42 in the battery element 40.
  • the battery element 40 has a three-dimensional shape similar to that of the outer can 10. Specifically, the battery element 40 has a flat, approximately cylindrical three-dimensional shape. Compared to a case in which the battery element 40 has a three-dimensional shape different from that of the outer can 10, when the battery element 40 is stored inside the outer can 10, so-called dead space, specifically, a gap between the outer can 10 and the battery element 40, is less likely to occur. For this reason, the internal space of the outer can 10 is effectively utilized. As a result, the element space volume increases, and the energy density per unit volume of the secondary battery increases.
  • the 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.
  • the positive electrode collector 41A has a pair of surfaces on which the positive electrode active material layer 41B is provided.
  • the positive electrode collector 41A contains a conductive material such as a metal material, and the metal material is aluminum, for example.
  • the positive electrode active material layer 41B is provided on both sides of the positive electrode 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 collector 41A.
  • the positive electrode active material layer 41B may further contain a positive electrode binder and a positive electrode conductive agent.
  • the method of forming the positive electrode active material layer 41B is not particularly limited, but specifically includes a coating method.
  • the positive electrode active material contains a lithium compound.
  • This lithium compound is a general term for compounds that contain lithium as a constituent element, and more specifically, is a compound that contains lithium as well as one or more transition metal elements as constituent elements. This is because a high energy density can be obtained.
  • the lithium compound may further contain any one or more of other elements (excluding lithium and transition metal elements).
  • the type of lithium compound is not particularly limited, but 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.
  • the positive electrode binder contains one or more of synthetic rubber and polymer compounds.
  • the synthetic rubber is styrene butadiene rubber, and the polymer compound is polyvinylidene fluoride.
  • the positive electrode conductor contains one or more of conductive materials such as carbon materials, and the carbon materials are graphite, carbon black, acetylene black, and ketjen black.
  • the conductive material may also be a metal material, a polymer compound, etc.
  • 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.
  • 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.
  • the negative electrode active material layer 42B is provided on both sides of the negative electrode 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 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, but specifically, it is one or more types of a coating method, a gas phase method, a liquid phase method, a thermal spraying method, and a baking method (sintering method).
  • 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).
  • Metal-based materials are materials that contain one or more metal elements and semi-metal elements that can form an alloy with lithium as constituent elements, and the metal elements and semi-metal elements are one or both of silicon and tin.
  • the metal-based material may be a simple substance, an alloy, a compound, a mixture of two or more of these, or a material containing two or more of these phases. Specific examples of metal-based materials include TiSi2 and SiOx (0 ⁇ x ⁇ 2, or 0.2 ⁇ x ⁇ 1.4).
  • the height of the negative electrode 42 is greater than the height of the positive electrode 41. That is, the negative electrode 42 protrudes upward from the positive electrode 41 and also protrudes downward from the positive electrode 41. This is to prevent the lithium released from the positive electrode 41 from precipitating.
  • This "height" is the dimension corresponding to the height H of the secondary battery described above, that is, the dimension in the vertical direction in each of Figures 1 and 2. The definition of height explained here will be the same hereafter.
  • the separator 43 is an insulating porous film disposed between the positive electrode 41 and the negative electrode 42.
  • 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.
  • the height of the separator 43 is greater than the height of the negative electrode 42.
  • the separator 43 preferably protrudes upward from the negative electrode 42 and downward from the negative electrode 42.
  • 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.
  • the positive electrode lead 51 is housed inside the exterior can 10.
  • the positive electrode lead 51 is a connection wire connected to each of the positive electrode 41 and the external terminal 20.
  • 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.
  • the positive electrode lead 51 is connected to the upper end of the positive electrode 41. Specifically, the positive electrode lead 51 is connected to the upper end of the positive electrode current collector 41A. The positive electrode lead 51 is also connected to a part of the surface 20S of the external terminal 20 via a through hole 12K provided in the lid portion 12.
  • the method of connecting the positive electrode lead 51 is not particularly limited, but specifically, it is any one or more of welding methods such as resistance welding and laser welding. The details of the welding methods described here will also be applied hereinafter.
  • the positive electrode lead 51 includes a first portion 511, a second portion 512, and a folded portion 513.
  • the first portion 511 and the second portion 512 extend along a horizontal plane perpendicular to the height direction Z of the secondary battery.
  • the first portion 511 and the second portion 512 overlap each other in the height direction Z of the secondary battery via the sealant 61.
  • the folded portion 513 is curved so as to connect the first portion 511 and the second portion 512.
  • the first portion 511 and the second portion 512 are sandwiched between the battery element 40 and the recessed portion 12H of the lid portion 12 in the height direction Z of the secondary battery.
  • FIG. 4A is a plan view showing an example of the configuration of the positive electrode lead 51.
  • FIG. 4A shows a schematic view of the joint between the positive electrode lead 51 and the external terminal 20 as viewed from the battery element 40 inside the outer can 10.
  • FIG. 4B is a cross-sectional view showing a cross section along the longitudinal direction of the positive electrode lead 51.
  • FIG. 4B shows a cross section of the positive electrode lead 51 along the line IVB-IVB shown in FIG. 4A.
  • FIG. 4C is a cross-sectional view showing a cross section along the width direction of the positive electrode lead 51 perpendicular to the longitudinal direction.
  • FIG. 4C shows a cross section of the positive electrode lead 51 along the line IVC-IVC shown in FIG. 4A.
  • FIGS. 4A to 4C show an enlarged view of the vicinity of the welded portion of the positive electrode lead 51 welded to the back surface 20BS of the external terminal 20. Also, in FIGS. 4A to 4C, the longitudinal direction of the positive electrode lead 51 is the L-axis direction, and the width direction of the positive electrode lead 51 is the W-axis direction.
  • the positive electrode lead 51 has a first end 51A, a central portion 51C, and a second end 51B in this order along a width direction (W axis direction) perpendicular to the longitudinal direction (L axis direction).
  • the central portion 51C is flat so as to extend along the back surface 20BS of the external terminal 20, and includes one or more welding points WP welded to the back surface 20BS of the external terminal 20. Two welding points WP1 and WP2 are illustrated in FIG. 4A and FIG. 4B.
  • the first end 51A and the second end 51B of the positive electrode lead 51 are bent in a direction away from the back surface 20BS of the external terminal 20. Note that FIG.
  • 4C illustrates a case in which both the first end 51A and the second end 51B are bent, but in the present disclosure, it is sufficient that at least one of the first end 51A and the second end 51B is bent in a direction away from the back surface 20BS of the external terminal 20.
  • the positive electrode lead 51 may further have two recesses U1, U2.
  • the two recesses U1, U2 are formed on the front surface 51FS of the central portion 51C opposite the back surface 20BS of the external terminal 20, and are aligned in the longitudinal direction (L-axis direction) of the positive electrode lead 51.
  • the planar shape of the recesses U1, U2 is, for example, approximately semicircular or approximately partially annular.
  • one or more welding points WP are located between the recesses U1 and U2.
  • the width dimension of the positive electrode lead 51 is 4 mm or less.
  • the positive electrode lead 51 includes a flat central portion 51C and a first end portion 51A and a second end portion 51B that are located on either side of the central portion 51C and bent in a direction away from the back surface 20BS, so that the shape of the positive electrode lead 51 is less likely to be deformed by external forces. Therefore, for example, when the positive electrode lead 51 is welded to the back surface 20BS, the flatness of the central portion 51C is less likely to be damaged. Therefore, the central portion 51C and the back surface 20BS are welded with high welding strength. As a result, even if the secondary battery is subjected to external forces such as vibration and impact, the positive electrode lead 51 is less likely to fall off from the back surface 20BS of the external terminal 20.
  • a portion of the positive electrode lead 51 extends along the underside of the lid 12 and the upper surface of the battery element 40, and is thereby held by the lid 12 and the battery element 40. Therefore, the positive electrode lead 51 is fixed inside the exterior can 10. Even if the secondary battery is subjected to external forces such as vibration and impact, the positive electrode lead 51 is less likely to move, and therefore the positive electrode lead 51 is less likely to be damaged. Damage to the positive electrode lead 51 here refers to the occurrence of cracks in the positive electrode lead 51, the positive electrode lead 51 being cut, the positive electrode lead 51 falling off from the positive electrode 41, etc.
  • a part of the positive electrode lead 51 is sandwiched between the outer can 10 and the battery element 40
  • the positive electrode lead 51 is insulated from the outer can 10 and the battery element 40 while being held from above and below by the outer can 10 and the battery element 40, so that the positive electrode lead 51 is unlikely to move inside the outer can 10 even if the secondary battery is subjected to external forces such as vibration and impact.
  • the fact that the positive electrode lead 51 is unlikely to move inside the outer can 10 means that the battery element 40 is also unlikely to move inside the outer can 10. Therefore, when the secondary battery is subjected to vibration or impact, problems such as collapse of the winding of the battery element 40, which is a wound electrode body, can be avoided.
  • the lid portion 12 includes a recessed portion 12H, and a portion of the positive electrode lead 51 is sandwiched between the recessed portion 12H and the battery element 40. That is, a portion of the positive electrode lead 51 extends along the lower surface of the recessed portion 12H and the upper surface of the battery element 40, and is thereby held by the recessed portion 12H and the battery element 40.
  • the recessed portion 12H makes it easier to hold the positive electrode lead 51, making the positive electrode lead 51 less likely to be damaged.
  • a portion of the positive electrode lead 51 is insulated from the lid portion 12 and the negative electrode 42 via the separator 43, the sealant 61, and the insulating films 62, 63, respectively.
  • the height of the separator 43 is greater than the height of the negative electrode 42.
  • a portion of the positive electrode lead 51 is separated from the negative electrode 42 via the separator 43, and is therefore insulated from the negative electrode 42 via the separator 43. This is because a short circuit between the positive electrode lead 51 and the negative electrode 42 is prevented.
  • the positive electrode lead 51 is also coated with an insulating sealant 61. This insulates a portion of the positive electrode lead 51 from the lid 12 and the negative electrode 42 via the sealant 61. This is because a short circuit between the positive electrode lead 51 and the lid 12 is prevented, and a short circuit between the positive electrode lead 51 and the negative electrode 42 is also prevented.
  • an insulating film 62 is disposed between the lid portion 12 and the positive electrode lead 51.
  • a portion of the positive electrode lead 51 is insulated from the lid portion 12 via the insulating film 62. This is because a short circuit between the positive electrode lead 51 and the lid portion 12 is prevented.
  • an insulating film 63 is disposed between the battery element 40 and the positive electrode lead 51. As a result, a portion of the positive electrode lead 51 is insulated from the negative electrode 42 via the insulating film 63. This is because a short circuit between the positive electrode lead 51 and the negative electrode 42 is prevented.
  • the details regarding the material for the positive electrode lead 51 are similar to the details regarding the material for the positive electrode collector 41A. However, the materials for the positive electrode lead 51 and the positive electrode collector 41A may be the same or different.
  • the positive electrode lead 51 is connected to the positive electrode 41 in a region in front of the center line PC, i.e., in a region to the right of the center line PC in FIG. 2.
  • the positive electrode lead 51 has a folded portion 513 on the way to the external terminal 20 in order to be connected to the external terminal 20.
  • the folded portion 513 is present in a region behind the center line PC, i.e., in a region to the left of the center line PC in FIG. 2.
  • the positive electrode lead 51 has a first portion 511 as a portion from the point where it is connected to the positive electrode 41 through the center position P0 to the folded portion 513.
  • the first portion 511 extends in a direction perpendicular to the height direction Z along the upper surface of the battery element 40.
  • the positive electrode lead 51 has a second portion 512 as a portion on the way from the folded portion 513 to the point where it is connected to the external terminal 20.
  • the second portion 512 extends in a direction perpendicular to the height direction Z along the upper surface of the battery element 40 so as to cover the first portion 511.
  • a portion of the positive electrode lead 51 extends toward the external terminal 20 while being sandwiched between the lid portion 12 and the battery element 40 in both the region in front of the center line PC and the region behind the center line PC.
  • the "region in front of the center line PC” refers to one of the regions in which the connection point of the positive electrode lead 51 to the positive electrode 41 exists when the battery element 40 is divided into two regions in the direction along the outer diameter D with the center line PC as a reference.
  • the "region in front of the center line PC” is the region to the right of the center line PC.
  • the "region behind the center line PC” refers to the other of the two regions described above, which is the region to the left of the center line PC in FIG. 2.
  • the "region behind the center line PC" refers to the other region in which the connection point of the positive electrode lead 51 to the positive electrode 41 does not exist when the battery element 40 is divided into two regions in the direction along the outer diameter D with the center line PC as a reference.
  • 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 connected to the positive electrode 41 on the inner side of the outermost circumference of the positive electrode 41. This is because, unlike the case where the positive electrode lead 51 is connected to the positive electrode 41 at the outermost circumference of the positive electrode 41, corrosion of the outer can 10 caused by the electrolyte creeping up is prevented.
  • This "electrolyte creeping up” refers to the electrolyte in the battery element 40 creeping up the positive electrode lead 51 and reaching the inner wall surface of the outer can 10 when the positive electrode lead 51 is disposed close to the inner wall surface of the outer can 10.
  • the outer can 10 dissolves or discolors.
  • the positive electrode lead 51 is folded back at least once between the positive electrode 41 and the external terminal 20, and is therefore folded over at least once.
  • the number of times the positive electrode lead 51 is folded back is not particularly limited as long as it is at least once.
  • the positive electrode lead 51 is folded back means that the extension direction of the positive electrode lead 51 changes midway so that it forms an angle greater than 90°.
  • the folded back portion of the positive electrode lead 51 may have a curved shape, like the folded back portion 513, without bending.
  • FIG. 2 illustrates an example in which the positive electrode lead 51 includes one folded back portion 513, it may include multiple folded back portions 513.
  • the positive electrode lead 51 is folded back at a folding back portion 513 midway from the positive electrode 41 to the external terminal 20.
  • the first portion 511 extends from a first position P1 other than the position P0 at the center of the outer casing 10 to a second position P2 on the opposite side of the first position P1 as viewed from the center position in a horizontal plane perpendicular to the height direction of the secondary battery.
  • the second portion 512 extends from the second position P2 toward the center position P0.
  • the overlapping portion of the first portion 511 and the second portion 512 is an excess portion. In other words, it can be said that the positive electrode lead 51 has a length margin in its longitudinal direction.
  • the storage section 11 and the lid section 12 are used to form the outer can 10 in the manufacturing process of the secondary battery, there is sufficient room to change the position of the lid section 12 relative to the storage section 11.
  • the secondary battery is subjected to external forces such as vibration and impact, the external forces are mitigated by utilizing the length margin of the positive electrode lead 51, making the positive electrode lead 51 less likely to be damaged.
  • the length margin of the positive electrode lead 51 it is possible to arbitrarily change the connection position of the positive electrode lead 51 relative to the positive electrode 41 without changing the length of the positive electrode lead 51.
  • the length of the positive electrode lead 51 (total length including the length margin) is not particularly limited and can be set arbitrarily.
  • the length of the positive electrode lead 51 is preferably at least half the outer diameter D of the outer can 10. This is because the length of the positive electrode lead 51 ensures a length margin for standing the lid portion 12 against the storage portion 11, making it easier to stand the lid portion 12 against the storage portion 11.
  • connection range of the positive electrode lead 51 to the external terminal 20 is not particularly limited.
  • the connection range of the positive electrode lead 51 to the external terminal 20 is preferably sufficiently wide so that the positive electrode lead 51 is unlikely to fall off the external terminal 20, and is also preferably sufficiently narrow so that a length margin of the positive electrode lead 51 can be obtained.
  • the reason why the connection range of the positive electrode lead 51 to the external terminal 20 is preferably sufficiently narrow is that the portion of the positive electrode lead 51 that is not connected to the external terminal 20 becomes the length margin, and therefore the length margin of the positive electrode lead 51 becomes sufficiently large.
  • the positive electrode lead 51 is provided separately from the positive electrode collector 41A. However, since the positive electrode lead 51 is physically continuous with the positive electrode collector 41A, it may be integrated with the positive electrode collector 41A.
  • the negative electrode lead 52 is stored inside the exterior can 10.
  • the negative electrode lead 52 is electrically connected to each of the negative electrode 42 and the exterior can 10 (storage section 11). Therefore, the storage section 11 (bottom M2) is electrically connected to the negative electrode 42 via the negative electrode lead 52.
  • the secondary battery includes one negative electrode lead 52. However, the secondary battery may include two or more negative electrode leads 52.
  • 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 storage section 11. There are no particular limitations on the method of connecting the negative electrode lead 52, but specifically, it is any one or more of the welding methods such as resistance welding and laser welding.
  • the negative electrode lead 52 may have a configuration similar to that of the positive electrode lead 51 shown in Figures 4A to 4C.
  • Figure 5A is a plan view showing an example of the configuration of the negative electrode lead 52. Specifically, Figure 5A shows a schematic view of the joint between the negative electrode lead 52 and the bottom M2 as viewed from the battery element 40 inside the outer can 10.
  • Figure 5B is a cross-sectional view showing a cross section along the longitudinal direction of the negative electrode lead 52. Specifically, Figure 5B shows a cross section of the negative electrode lead 52 along the line VB-VB shown in Figure 5A.
  • Figure 5C is a cross-sectional view showing a cross section of the negative electrode lead 52 along the width direction perpendicular to the longitudinal direction.
  • Figure 5C shows a cross section of the negative electrode lead 52 along the line VC-VC shown in Figure 5A.
  • Figures 5A to 5C show an enlarged view of the vicinity of the welded portion of the negative electrode lead 52 welded to the inner surface M2S of the bottom M2.
  • the longitudinal direction of the negative electrode lead 52 is the L-axis direction
  • the width direction of the negative electrode lead 52 is the W-axis direction.
  • the negative electrode lead 52 has a first end 52A, a central portion 52C, and a second end 52B in this order along the width direction (W-axis direction) perpendicular to the longitudinal direction (L-axis direction).
  • the central portion 52C is flat so as to extend along the inner surface M2S of the bottom portion M2, and includes one or more welded portions WP welded to the inner surface M2S.
  • FIGS. 5A and 5B two welded portions WP1 and WP2 are illustrated.
  • the first end 52A and the second end 52B of the negative electrode lead 52 are bent in a direction away from the inner surface M2S of the bottom portion M2.
  • FIG. 5C illustrates an example in which both the first end 52A and the second end 52B are bent, but in the present disclosure, it is sufficient that at least one of the first end 52A and the second end 52B is bent in a direction away from the inner surface M2S of the bottom portion M2.
  • the negative electrode lead 52 may further have two recesses U1 and U2, similar to the positive electrode lead 51. If the outer diameter D of the exterior can 10 of the secondary battery is, for example, 16 mm, the width dimension of the negative electrode lead 52 is 4 mm or less.
  • the negative electrode lead 52 has the same configuration as the positive electrode lead 51, so that, for example, when the negative electrode lead 52 is welded to the inner surface M2S, the flatness of the central portion 52C is unlikely to be damaged. Therefore, the central portion 52C and the inner surface M2S are welded with high welding strength. As a result, even if the secondary battery is subjected to external forces such as vibration and impact, the negative electrode lead 52 is unlikely to fall off from the inner surface M2S of the bottom portion M2.
  • the details regarding the material for the negative electrode lead 52 are similar to the details regarding the material for the negative electrode current collector 42A. However, the material for the negative electrode lead 52 and the material for the negative electrode current collector 42A may be the same as or different from each other.
  • connection position of the negative electrode lead 52 to the negative electrode 42 is not particularly limited and can be set arbitrarily.
  • the negative electrode lead 52 is connected to the outermost peripheral portion of the negative electrode 42 that constitutes the wound electrode body.
  • the negative electrode lead 52 is provided separately from the negative electrode current collector 42A. However, since the negative electrode lead 52 is physically continuous with the negative electrode current collector 42A, it may be integrated with the negative electrode current collector 42A.
  • the sealant 61 is a first insulating member that covers the periphery of the positive electrode lead 51, and is formed by attaching two pieces of insulating tape to the front and back surfaces of the positive electrode lead 51, respectively.
  • the sealant 61 covers the periphery of the middle part of the positive electrode lead 51 in order to connect the positive electrode lead 51 to the positive electrode 41 and the external terminal 20, respectively.
  • the sealant 61 is not limited to having a tape-like structure, and may have, for example, a tube-like structure.
  • the sealant 61 contains one or more types of insulating materials, such as insulating polymer compounds, such as polyimide.
  • 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 has a ring-shaped planar shape having an opening 62K at a position corresponding to the through hole 12K in the height direction Z.
  • the insulating film 62 may be adhered to the lid portion 12 via an adhesive layer.
  • the insulating film 62 may also contain one or more types of insulating materials, such as insulating polymer compounds.
  • the insulating material contained in the insulating film 62 is polyimide, for example.
  • the insulating film 63 is an insulating member disposed between the battery element 40 and the positive electrode lead 51.
  • the insulating film 63 has a flat plate-like shape.
  • the insulating film 63 is disposed so as to shield the winding center space 40K and to cover the battery element 40 around the winding center space 40K.
  • 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 each other or different from each other.
  • the secondary battery may further include one or more other components.
  • the secondary battery is equipped with a safety valve mechanism.
  • This safety valve mechanism is configured to cut off the electrical connection between the outer can 10 and the battery element 40 when the internal pressure of the outer can 10 reaches a certain level or higher.
  • causes of the internal pressure of the outer can 10 reaching a certain level or higher include a short circuit occurring inside the secondary battery and the secondary battery being heated from the outside.
  • the safety valve mechanism be installed on either the bottom portion M1 or M2, and it is more preferable that the safety valve mechanism be installed on the bottom portion M2 to which the external terminal 20 is not attached.
  • the secondary battery may also have an insulator other than the insulating films 62, 64 between the exterior can 10 and the battery element 40.
  • This insulator includes one or more types of insulating film and insulating sheet, etc., and prevents short-circuiting between the exterior can 10 and the battery element 40.
  • the installation range of the insulator is not particularly limited and can be set as desired.
  • the outer can 10 is provided with a splitting valve. This splitting valve splits when the internal pressure of the outer can 10 reaches a certain level or higher, thereby releasing the internal pressure.
  • a splitting valve splits when the internal pressure of the outer can 10 reaches a certain level or higher, thereby releasing the internal pressure.
  • the location of the splitting valve there are no particular limitations on the location of the splitting valve, but as with the location of the safety valve mechanism described above, either the bottom M1 or M2 is preferred, and bottom M2 is particularly preferred.
  • FIG. 5 shows a perspective view of an exterior can 10 used in the manufacturing process of a secondary battery, and corresponds to FIG.
  • FIG. 5 shows the state in which the lid portion 12 is separated from the storage portion 11 before the lid portion 12 is welded to the storage portion 11.
  • the storage section 11 is a roughly container-shaped member in which the bottom section M2 and the side wall section M3 are integrated with each other, and has an opening section 11K.
  • the lid section 12 is a roughly plate-shaped member that corresponds to the bottom section M1, and the external terminal 20 is attached in advance to the recess section 12H provided in the lid section 12 via a gasket 30.
  • 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.
  • the prepared positive electrode mixture is put into an organic solvent or the like to prepare a paste-like positive electrode mixture slurry.
  • the positive electrode mixture slurry is applied to both sides of the positive electrode current collector 41A to form a positive electrode active material layer 41B.
  • 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.
  • the negative electrode 42 is produced by the same procedure as that of 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 the negative electrode current collector 42A to form the negative electrode active material layer 42B. At that time, the thickness T2 of the negative electrode outer active material layer 42B2 covering the negative electrode current collector outer surface 42A2 is made thicker than the thickness T1 of the negative electrode inner active material layer 42B1 covering the negative electrode current collector inner surface 42A1. Then, 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.
  • electrolyte solution 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.
  • the positive electrode lead 51 whose periphery is covered with a sealant 61, is connected to the positive electrode 41 (positive electrode current collector 41A), and the negative electrode lead 52 is connected to the negative electrode 42 (negative electrode current collector 42A).
  • the wound body 40Z has a similar configuration to 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. Note that the positive electrode lead 51 and the negative electrode lead 52 are not shown in FIG. 6.
  • the wound body 40Z to which the positive electrode lead 51 and the negative electrode lead 52 are connected is stored inside the storage section 11 through the opening 11K.
  • the negative electrode lead 52 is connected to the storage section 11 using a welding method such as resistance welding.
  • an insulating film 63 is placed on the wound body 40Z.
  • the cover 12 is prepared, to which the external terminal 20 is attached via the gasket 30 and to which the insulating film 62 is already provided, and then the positive electrode lead 51 is connected to the external terminal 20 via the through hole 12K using a welding method such as resistance welding.
  • the wound body 40Z (positive electrode 41) stored inside the storage section 11 and the external terminal 20 attached to the lid section 12 are connected to each other via the positive electrode lead 51.
  • the electrolyte is injected into the storage section 11 through the opening 11K.
  • the lid 12 does not close the opening 11K, so the electrolyte can be easily injected into the storage section 11 through the opening 11K.
  • the wound body 40Z including the positive electrode 41, the negative electrode 42, and the separator 43 is impregnated with the electrolyte, and the battery element 40, which is a wound electrode body, is produced.
  • the lid 12 is tilted down so as to approach the storage section 11, thereby closing the opening 11K with the lid 12, and then the lid 12 is welded to the storage section 11 using a welding method such as laser welding.
  • a welding method such as laser welding.
  • a part of the positive electrode lead 51 is sandwiched between the lid 12 and the battery element 40, and a curved folded portion 513 is formed in the positive electrode lead 51 before the connection point to the external terminal 20.
  • the outer can 10 is formed, and the battery element 40 and the like are stored inside the outer can 10, completing the assembly of the secondary battery.
  • 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.
  • a coating is formed on the surface of the negative electrode 42, etc., and the state of the secondary battery is electrochemically stabilized.
  • the secondary battery is completed.
  • the positive electrode lead 51 includes a flat central portion 51C, and a first end 51A and a second end 51B located on both sides of the central portion 51C and bent in a direction away from the back surface 20BS. Therefore, the welding strength between the flat central portion 51C and the back surface 20BS of the external terminal 20 is high. Therefore, even if an external mechanical load such as vibration or impact is applied to the battery, the positive electrode lead 51 does not come off the back surface 20BS of the external terminal 20, and the electrical connection between the positive electrode lead 51 (positive electrode 41) and the external terminal 20 can be maintained in a good condition.
  • the positive electrode lead 51 has two recesses U1 and U2 arranged in the longitudinal direction, the shape stability of the positive electrode lead 51 can be improved. That is, by providing two recesses U1 and U2, the shape of the positive electrode lead 51 including the flat central portion 51C and the first end 51A and the second end 51B located on both sides of the central portion 51C is more stably maintained.
  • the negative electrode lead 52 has two recesses U1, U2 aligned in the longitudinal direction, the shape stability of the negative electrode lead 52 can be improved.
  • the recesses U1 and U2 are formed, for example, by pressing a jig having an approximately semicircular or partially annular abutment surface against the surface of the positive electrode lead 51.
  • the planar shape of the recesses U1 and U2 is approximately semicircular or partially annular, so that it is possible to avoid the occurrence of cracks in the positive electrode lead 51 when forming the recesses U1 and U2.
  • the recesses U1 and U2 have an approximately semicircular or partially annular planar shape, the reliability of the secondary battery of this embodiment is improved.
  • the need to provide a welding point WP between the two recesses means that the distance between the two recesses tends to be wider than when recesses U1, U2 are provided with an approximately semicircular or partially annular shape. Therefore, by having recesses U1, U2 with an approximately semicircular or partially annular planar shape, it is easier to accommodate miniaturization of the secondary battery.
  • the negative electrode lead 52 further includes a flat central portion 52C, and a first end 52A and a second end 52B that are located on either side of the central portion 52C and bent in a direction away from the inner surface M2S.
  • This increases the welding strength between the flat central portion 52C and the inner surface M2S of the bottom portion M2. Therefore, even if an external mechanical load such as vibration or impact is applied to the secondary battery of this embodiment, the negative electrode lead 52 will not come off the inner surface M2S of the bottom portion M2, and good electrical connection can be maintained between the negative electrode lead 52 (negative electrode 42) and the outer can 10. Therefore, the secondary battery of this embodiment has high reliability.
  • a recessed portion 12H is provided in the lid portion 12, and the external terminal 20 is arranged in the recessed portion 12H. This makes it possible to reduce the height dimension of the secondary battery while ensuring the battery capacity.
  • the secondary battery is flat and columnar, that is, the secondary battery is called a coin type or button type secondary battery
  • the positive electrode lead 51 is less likely to be damaged even in small secondary batteries which are subject to significant size restrictions, and therefore greater effects can be obtained in terms of physical durability.
  • the secondary battery is a lithium-ion secondary battery, sufficient battery capacity can be obtained stably by utilizing the absorption and release of lithium.
  • the outer can is a welded can (crimpless can)
  • the configuration of the outer can is not particularly limited, and it may be a crimp can that has been crimped.
  • this crimp can the storage section and the lid section, which are separated from each other, are crimped together via a gasket.
  • the electrode reactant has been described as being lithium, the electrode reactant is not particularly limited. Therefore, as described above, the electrode reactant may be other alkali metals such as sodium and potassium, or alkaline earth metals such as beryllium, magnesium and calcium. In addition, the electrode reactant may be other light metals such as aluminum.
  • both the positive electrode lead 51 and the negative electrode lead 52 are described as having bent ends in the width direction, but in the present disclosure, it is sufficient that at least one of the positive electrode lead and the negative electrode lead has such a configuration.
  • the positive electrode lead 51 is connected to the external terminal 20, and the negative electrode lead 52 is connected to the storage section 11 of the exterior can 10, but the present disclosure is not limited to this. That is, in the secondary battery of the present disclosure, the negative electrode lead may be connected to the external terminal, and the positive electrode lead may be connected to the exterior member.
  • a secondary battery is used as an example for explanation, but the battery disclosed herein is not limited to a secondary battery and can also be applied to a primary battery.
  • a battery element including a first electrode and a second electrode; An exterior member that houses the battery element; an external terminal attached to the exterior member via an insulating member; a first electrode lead connecting the first electrode and an inner surface of the external terminal; a second electrode lead connecting the second electrode and an inner surface of the exterior member; Equipped with At least one of the first electrode lead and the second electrode lead has a first end, a central portion, and a second end in that order along a width direction perpendicular to a longitudinal direction of the lead, the central portion is flat and is welded to an inner surface of the external terminal or an inner surface of the exterior member, At least one of the first end and the second end is bent in a direction away from the inner surface of the external terminal or the inner surface of the exterior member.
  • ⁇ 2> The battery according to ⁇ 1> above, wherein both of the first end and the second end of at least one of the first electrode lead and the second electrode lead are bent in a direction away from the inner surface of the external terminal or the inner surface of the exterior member.
  • At least one of the first electrode lead and the second electrode lead is The external terminal has two recesses arranged in the longitudinal direction, the recesses being formed on an inner surface of the external terminal or on a surface of the exterior member opposite to the inner surface of the exterior member, The battery according to the above item ⁇ 1> or ⁇ 2>, wherein one or more welding points to an inner surface of the external terminal or an inner surface of the exterior member are provided between the two recesses.
  • the exterior member has a generally cylindrical outer shape with a diameter of 16 mm
  • the exterior member has a container including an insertion opening through which the battery element can be inserted in a first direction and capable of accommodating the battery element through the insertion opening, and a lid portion that closes the insertion opening and has a through-opening that penetrates in the first direction,
  • ⁇ 7> The battery according to ⁇ 6> above, wherein an outer edge of the lid portion is connected to the insertion hole of the storage container by welding.
  • the cover portion of the exterior member has a recessed portion recessed toward the battery element along the first direction, The battery according to ⁇ 6> or ⁇ 7> above, wherein the through hole is provided in the recess.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Sealing Battery Cases Or Jackets (AREA)
PCT/JP2023/037465 2022-12-01 2023-10-17 電池 Ceased WO2024116623A1 (ja)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE112023005022.8T DE112023005022T5 (de) 2022-12-01 2023-10-17 Batterie
JP2024561230A JP7800729B2 (ja) 2022-12-01 2023-10-17 電池
US19/080,286 US20250210826A1 (en) 2022-12-01 2025-03-14 Battery

Applications Claiming Priority (2)

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JP2022193112 2022-12-01
JP2022-193112 2022-12-01

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JP (1) JP7800729B2 (https=)
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0935739A (ja) * 1995-07-24 1997-02-07 Fuji Photo Film Co Ltd 円筒形電池およびその組立方法
JP2010157510A (ja) * 2008-12-31 2010-07-15 Samsung Sdi Co Ltd 二次電池
WO2017098690A1 (ja) * 2015-12-10 2017-06-15 パナソニックＩｐマネジメント株式会社 電池
WO2023100768A1 (ja) * 2021-11-30 2023-06-08 パナソニックＩｐマネジメント株式会社 蓄電装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0935739A (ja) * 1995-07-24 1997-02-07 Fuji Photo Film Co Ltd 円筒形電池およびその組立方法
JP2010157510A (ja) * 2008-12-31 2010-07-15 Samsung Sdi Co Ltd 二次電池
WO2017098690A1 (ja) * 2015-12-10 2017-06-15 パナソニックＩｐマネジメント株式会社 電池
WO2023100768A1 (ja) * 2021-11-30 2023-06-08 パナソニックＩｐマネジメント株式会社 蓄電装置

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JPWO2024116623A1 (https=) 2024-06-06
US20250210826A1 (en) 2025-06-26
DE112023005022T5 (de) 2025-10-16

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