WO2025246761A1 - 二次电池及电子设备 - Google Patents

二次电池及电子设备

Info

Publication number
WO2025246761A1
WO2025246761A1 PCT/CN2025/091506 CN2025091506W WO2025246761A1 WO 2025246761 A1 WO2025246761 A1 WO 2025246761A1 CN 2025091506 W CN2025091506 W CN 2025091506W WO 2025246761 A1 WO2025246761 A1 WO 2025246761A1
Authority
WO
WIPO (PCT)
Prior art keywords
sealing ring
secondary battery
hole
concave
electrode
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.)
Pending
Application number
PCT/CN2025/091506
Other languages
English (en)
French (fr)
Inventor
沈阳
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.)
Ningde Amperex Technology Ltd
Original Assignee
Ningde Amperex Technology 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 Ningde Amperex Technology Ltd filed Critical Ningde Amperex Technology Ltd
Publication of WO2025246761A1 publication Critical patent/WO2025246761A1/zh
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • 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
    • 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
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • 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
    • H01M50/184—Sealing members characterised by their shape or structure
    • 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
    • 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
    • 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
    • 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 application relates to the field of battery technology, and in particular to a secondary battery and electronic device.
  • Rechargeable batteries are crucial for the normal operation of mobile devices, serving as their power source. As mobile devices such as smartphones and laptops become increasingly prevalent, end-users are demanding higher capacity and longer battery life from rechargeable batteries. Hard-cased rechargeable batteries, compared to pouch batteries, can be designed to achieve significantly higher capacities.
  • the purpose of this application is to provide a secondary battery and electronic device, which aims to improve the technical problem of low strength and easy deformation of the secondary battery terminals, resulting in poor sealing performance.
  • a secondary battery including a housing, terminals, and a sealing assembly.
  • the housing includes a first wall portion having a first through hole, and the first wall portion includes a first wall surface and a second wall surface disposed opposite to each other, the first wall surface facing the inner cavity of the housing.
  • the terminals include a first portion, a second portion, and a third portion. The first portion is disposed within the housing, one end of the second portion is connected to the first portion, and the other end extends out of the housing from the first through hole, the third portion is connected to the second portion outside the housing .
  • the terminals also include a first hole, the opening of which is located on the surface of the third portion facing away from the second portion, and the outer surface of the second portion is provided with a first uneven structure.
  • the sealing assembly includes a first sealing ring, a second sealing ring, and a third sealing ring, the first sealing ring being disposed between the first wall surface and the first portion, the second sealing ring surrounding the second portion, and the third sealing ring being disposed between the second wall surface and the third portion.
  • a first hole is provided on the outer surface of the third part.
  • the welding equipment can realize the electrical connection between the electrode post and the electrode assembly at the first hole, without reserving space inside the housing. This not only facilitates operation but also improves the energy density of the secondary battery. Furthermore, because the electrical connection between the electrode post and the electrode assembly is simpler and more convenient, it is easier to improve the connection strength between the electrode post and the electrode assembly.
  • the first concave-convex structure increases the strength of the second part of the terminal post, reducing its deformation and thus decreasing the gap between the terminal post and the sealing ring, thereby improving the sealing performance of the secondary battery. Furthermore, the first concave-convex structure increases the connection area between the second sealing ring and the second part, further enhancing the sealing performance between the second sealing ring and the terminal post.
  • the aforementioned first concave-convex structure enhances the strength of the electrode post and increases the connection area between the second sealing ring and the electrode post, resulting in stronger sealing performance. Therefore, the length of the second part can be reduced, decreasing the space occupied by the electrode post and further improving the energy density of the secondary battery.
  • the projection of the first concave-convex structure overlaps with the first hole, and the first concave-convex structure is distributed on the outside of the first hole to reduce the influence of the first hole on the pole strength.
  • the projection of the first wall portion overlaps with the first hole along the first direction to facilitate electrical connection between the pole and the electrode assembly.
  • the first hole has a bottom wall, which is disposed opposite to the opening along the direction from the first wall surface to the second wall surface.
  • the bottom wall of the first hole is located on the side of the first wall portion away from the third portion, leaving enough space to facilitate the electrical connection between the pole and the electrode assembly and improve the connection strength.
  • the second sealing ring is provided with a second concave-convex structure, which fits into the first concave-convex structure, can fully fill the gap between the second part and the housing, and can increase the connection area between the second sealing ring and the second part, thereby improving the sealing performance between the pole and the housing.
  • the first convex-concave structure is an external thread provided on the outer surface of the second portion
  • the second convex-concave structure is an internal thread provided on the second sealing ring, with the second sealing ring threadedly connected to the second portion.
  • the second sealing ring can be threadedly connected to the second portion by rotating it, making installation convenient and quick.
  • the secondary battery further includes a gasket disposed between the third portion and the third sealing ring.
  • the gasket isolates the third portion from the third sealing ring, reducing direct pressure damage to the third sealing ring during riveting.
  • the length of the first portion is L1 , 0.1mm ⁇ L1 ⁇ 3mm ; the length of the second portion is L2 , 0.5mm ⁇ L2 ⁇ 5mm ;
  • the length of the third part is L3 , where 0.1mm ⁇ L3 ⁇ 3mm. Adaptively reducing the length of the second part decreases the space occupied by the electrode post, thereby increasing the energy density of the secondary battery.
  • the length of the third portion is L3
  • the length of the second portion is L2
  • the depth of the first hole is D, where L3 + L2 / 2 ⁇ D ⁇ L3 + L2 .
  • the electrode post includes at least one of aluminum, copper, or aluminum alloy, which has good electrical conductivity, thermal conductivity, corrosion resistance, etc., and is highly machinable, making it easy to rivet and seal the electrode post.
  • the first, second, and third parts are integrally formed. There are no connection gaps between the three parts, improving sealing performance. Furthermore, the integral form provides greater strength and stronger resistance to deformation after riveting, reducing installation gaps caused by deformation and thus improving sealing performance.
  • the first convex-concave structure includes a first protrusion having a bottom near the first hole and a top away from the first hole.
  • the width of the bottom is W1
  • the width of the top is W2 , where W2 ⁇ W1 .
  • a larger top width can improve the strength and deformation resistance of the second part.
  • a smaller top width facilitates the embedding of the second sealing ring between adjacent first protrusions, improving sealing performance.
  • the distance from bottom to top is H, where 0.1mm ⁇ H ⁇ 1mm. This facilitates the installation of the second sealing ring while ensuring full engagement between the second sealing ring and the first convex-concave structure, increasing the connection area and thus improving sealing performance.
  • the thickness of the second part along the direction from the first hole to the first concave-convex structure is T, 0.5mm ⁇ T ⁇ 2mm, which can reduce the deformation or skewing of the pole post, and the hollow structure makes the electrical connection between the pole post and the electrode assembly more convenient.
  • this application also proposes an electronic device including a secondary battery as described in any of the embodiments of the first aspect above.
  • Figure 1 is a schematic diagram of the structure of a secondary battery according to some embodiments of this application.
  • Figure 2 is a schematic diagram of the structure of the housing in some embodiments of this application.
  • Figure 3 is a schematic diagram of the structure of a secondary battery according to some embodiments of this application.
  • Figure 4 is a partial schematic diagram of the pole post riveting structure of some embodiments of this application.
  • Figure 5 is a partial exploded view of the pole post riveting structure of some embodiments of this application.
  • Figure 6 is a schematic diagram of the structure of a secondary battery according to some embodiments of this application.
  • Figure 7 is a magnified view of part A in Figure 5.
  • the term "and/or” is merely a description of the relationship between related objects, indicating that three relationships can exist.
  • a and/or B can represent: A existing alone, A and B existing simultaneously, and B existing alone.
  • the character "/" in this document generally indicates that the preceding and following related objects have an "or" relationship.
  • the secondary battery 100 includes a housing 10, an electrode assembly 20, a terminal post 30, and a sealing assembly 40.
  • the electrode assembly 20 is disposed within the housing 10.
  • One end of the terminal post 30 is electrically connected to the electrode assembly 20, and the other end extends outside the housing 10.
  • the sealing assembly 40 is disposed between the terminal post 30 and the housing 10, serving to insulate and separate the terminal post 30 from the housing 10, and to seal the installation gap between the terminal post 30 and the housing 10.
  • the housing 10 encloses an inner cavity 11.
  • the secondary battery 100 also includes an electrode assembly 20 and an electrolyte (not shown in the figures), both of which are housed within the inner cavity 11.
  • the housing 10 includes a first wall portion 12, located at the top of the housing 10 and covering the inner cavity 11.
  • the first wall portion 12 includes a first wall surface 121 and a second wall surface 122 disposed opposite to each other.
  • the first wall surface 121 faces the inner cavity 11 of the housing 10, and the second wall surface 122 faces away from the inner cavity 11 of the housing 10.
  • the first wall portion 12 has a first through hole 13, which penetrates the first wall surface 121 and the second wall surface 122, communicating with the inner cavity 11 of the housing 10.
  • the aforementioned electrode post 30 can be installed at the first through hole 13.
  • the secondary battery 100 can be a hard-shell secondary battery 100
  • the casing 10 can be a structure formed by stamping a single layer of metal sheet, such as a single layer of steel sheet, which can improve the strength of the casing 10 and its resistance to deformation.
  • the casing 10 can also be made of metal materials such as stainless steel, nickel, or copper.
  • the hard-shell secondary battery 100 in this application can be designed to achieve a higher capacity, which is convenient for meeting the design requirements of large capacity and long battery life of the secondary battery 100.
  • the electrode assembly 20 is disposed within the inner cavity 11 of the housing 10.
  • the electrolyte can wet the electrode assembly 20 within the inner cavity 11 of the housing 10 to achieve an electrochemical reaction.
  • the electrode assembly 20 can adopt a stacked structure, comprising a positive electrode (not shown in the figure), a negative electrode (not shown in the figure), and a separator (not shown in the figure).
  • a plurality of positive electrode plates and a plurality of negative electrode plates are alternately stacked, and the separator is disposed between the positive electrode plates and the negative electrode plates to insulate and separate them.
  • the electrode assembly 20 may also adopt a wound structure, that is, the positive electrode sheet, the separator and the negative electrode sheet are stacked and wound together to form a wound electrode assembly 20.
  • the aforementioned terminal post 30 acts as a "bridge” connecting to an external circuit, responsible for conducting the current generated inside the secondary battery 100 to the external circuit and conducting external current into the secondary battery 100.
  • the terminal post 30 can be disposed in the first through hole 13 of the housing 10, with one end of the terminal post 30 electrically connected to the electrode assembly 20 within the inner cavity 11 of the housing 10, for example, connected to the tab 21 of the electrode assembly 20, while the other end extends outside the housing 10 to connect to an external circuit, thereby enabling the charging and discharging of the secondary battery 100.
  • the tab 21 can be sheet-like, plate-like, disc-like, or columnar, as long as it can electrically connect to the terminal post 30.
  • the housing 10 is a metal housing 10, which is conductive and can be used as the positive or negative electrode of the secondary battery 100.
  • the terminal 30 serves as the positive electrode of the secondary battery 100 and is electrically connected to the positive electrode of the electrode assembly 20, while the housing 10 serves as the negative electrode, with the negative electrode of the electrode assembly 20 directly electrically connected to the housing 10; when the terminal 30 serves as the negative electrode, the housing 10 can serve as the positive electrode.
  • at least two terminals 30 may be used, with at least one terminal 30 serving as the positive electrode of the secondary battery 100 and at least one terminal 30 serving as the negative electrode of the secondary battery 100.
  • the electrode post 30 can adopt a riveted structure.
  • the electrode post 30 includes a first part 31, a second part 32, and a third part 33.
  • the first part 31 is disposed inside the housing 10 and is electrically connected to the electrode assembly 20, for example, through the tab 21 to the positive or negative electrode plate of the electrode assembly 20.
  • One end of the second part 32 is connected to the first part 31, and the other end extends out of the housing 10 through the first through hole 13.
  • the third part 33 is connected to the second part 32 outside the housing 10 and is used for electrical connection to an external circuit.
  • the electrode post 30 is cylindrical in shape. It can be first placed in the first through hole 13, and then both ends of the electrode post 30 can be riveted and flattened to form the first part 31, the second part 32, and the third part 33. After riveting, along the first direction X, the widths of the first part 31 and the third part 33 are both greater than the width of the second part 32. The first part 31 and the third part 33 clamp the second part 32, reducing the likelihood of the electrode post 30 detaching from the housing 10.
  • the first part 31, the second part 32, and the third part 33 are integrally formed, with no connection gap between the three parts, which improves the sealing performance. Furthermore, the integral form has greater strength and stronger resistance to deformation after riveting, which can reduce the installation gap caused by deformation and thus improve the sealing performance.
  • the electrode post 30 comprises at least one of aluminum, copper, or an aluminum alloy.
  • the electrode post 30 is made of aluminum.
  • Aluminum electrode posts 30 have good electrical conductivity, thermal conductivity, corrosion resistance, and ductility, and are highly machinable, facilitating the riveting and sealing of the electrode post 30. During riveting, the aluminum electrode post 30 can be slightly compressed, thereby filling the gap between the electrode post 30 and the sealing assembly 40 and improving the sealing performance.
  • the sealing assembly 40 is disposed between the terminal post 30 and the housing 10 to seal the installation gap between the terminal post 30 and the housing 10, thereby sealing the inner cavity 11 of the housing 10.
  • the sealing assembly 40 can also insulate and separate the terminal post 30 and the housing 10.
  • the sealing assembly 40 includes a first sealing ring 41, a second sealing ring 42, and a third sealing ring 43.
  • the first sealing ring 41 is disposed between the first wall surface 121 and the first portion 31, serving to separate the first portion 31 from the housing 10.
  • the second sealing ring 42 is disposed around the second portion 32, serving to separate the second portion 32 from the housing 10.
  • the third sealing ring 43 is disposed between the second wall surface 122 and the third portion 33, serving to separate the third portion 33 from the housing 10.
  • the first sealing ring 41, the second sealing ring 42, and the third sealing ring 43 may be made of at least one of polypropylene (PP), polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyamide (PA), or phenolic resin (PF).
  • PP polypropylene
  • PE polyethylene
  • PS polystyrene
  • PVC polyvinyl chloride
  • PET polyethylene terephthalate
  • PA polyamide
  • PF phenolic resin
  • using phenolic resin provides the sealing rings with superior heat resistance and electrical insulation.
  • the secondary battery 100 further includes a gasket 50, which is disposed between the third portion 33 and the third sealing ring 43.
  • the gasket 50 can isolate the third portion 33 from the third sealing ring 43, reducing direct pressure damage to the third sealing ring 43 by the third portion 33 during riveting.
  • the gasket 50 can be a metal gasket, such as stainless steel, carbon steel, or copper, suitable for high-voltage conditions.
  • the gasket 50 may also be made of rubber, plastic, or polytetrafluoroethylene.
  • a gasket 50 may also be provided between the first part 31 and the first sealing ring 41 to reduce direct pressure damage to the first sealing ring 41 by the first part 31 and improve the integrity of the sealing assembly 40.
  • the electrode post 30 may have a hollow structure.
  • the electrode post 30 further includes a first hole 34, the opening of which is located on the surface of the third portion 33 opposite to the second portion 32.
  • the first hole 34 may penetrate the third portion 33, or extend from the third portion 33 into the second portion 32, or simultaneously penetrate both the third portion 33 and the second portion 32, or penetrate both the third portion 33 and the second portion 32 and extend into the first portion 31.
  • the hollow structure of the electrode post 30 facilitates electrical connection between the electrode post 30 and the electrode assembly 20 from outside the housing 10.
  • Electrical connection methods include, but are not limited to, welding, conductive adhesive bonding, or snap-fitting.
  • the welding equipment extends from outside the housing 10 into the first hole 34 of the electrode post 30.
  • the tab 21 of the electrode assembly 20 which is electrically connected to the positive or negative electrode plate, serving as a connecting adapter
  • laser penetration welding is performed to weld and fix the electrode post 30 to the tab. This eliminates the need for pre-reserved space within the housing 10, simplifying operation and increasing the energy density of the secondary battery 100.
  • the simpler and more convenient electrical connection between the electrode post 30 and the electrode assembly 20 enhances the connection strength.
  • the welding method is not limited to laser welding; ultrasonic welding or electron beam welding can also be used.
  • Figure 5 is a partially exploded view of the riveted structure of the pole post 30, with only a portion of each sealing ring shown).
  • the outer surface of the second part 32 is provided with a first concave-convex structure 321.
  • the provision of the first concave-convex structure 321 improves the strength of the second part 32 and reduces the deformation of the second part 32, such as reducing the riveting or collision deformation of the pole post 30, thereby reducing the installation gap caused by the deformation of the pole post 30 and improving the sealing performance between the second sealing ring 42 and the pole post 30.
  • the pole post 30 has higher strength and stronger resistance to deformation. Even with a hollow structure, the pole post still has high strength.
  • the projection of the first concave-convex structure 321 overlaps with the first hole 34, and the first concave-convex structure 321 is distributed on the outside of the first hole 34, reducing the influence of the first hole 34 on the strength of the electrode post 30. It should be noted that the portion of the electrode post 30 with the first hole 34 has weaker strength, while the portion without the first hole 34 still has higher strength.
  • the first concave-convex structure 321 can be provided only on the outside of the electrode post 30 with the first hole 34, reducing the influence of the first hole 34 on the strength of the electrode post 30, while the portion without the first hole 34 (e.g., the portion of the first part 31 or the second part 32 where the first hole 34 is not reached) does not need to have the first hole 34, reducing the space occupied by the first concave-convex structure 321 and reducing the impact on the energy density of the secondary battery 100.
  • the first direction X is perpendicular to the direction from the first wall 121 to the second wall 122 (the third direction Z).
  • the first direction X, the second direction Y, and the third direction Z are all perpendicular to each other; along the second direction Y, the projection of the first concave-convex structure 321 also overlaps with the first hole 34.
  • the first sealing ring 41, the second sealing ring 42, and the third sealing ring 43 can all be made of flexible material to fully fill the installation gap between the pole post 30 and the housing 10.
  • the second sealing ring 42 When the second sealing ring 42 is arranged around the second part 32, the second sealing ring 42 can fill the first concave-convex structure 321 and cooperate with the first concave-convex structure 321.
  • the arrangement of the first concave-convex structure 321 can increase the connection area between the second sealing ring 42 and the second part 32, which can further improve the sealing performance between the second sealing ring 42 and the pole post 30.
  • the first uneven structure 321 can be a protruding part and/or a recessed groove on the outer surface of the second part 32.
  • the uneven setting increases the friction between the second part 32 and the second sealing ring 42 and increases the connection area between the second part 32 and the second sealing ring 42, resulting in stronger sealing performance.
  • the portion of the second part 32 that contacts the second sealing ring 42 may be provided with a first concave-convex structure 321, thereby increasing the connection area between the second part 32 and the second sealing ring 42. A larger contact area results in stronger sealing performance. Since the third sealing ring 43 is disposed between the second wall surface 122 and the third part 33, the third sealing ring 43 may also contact the second part 32. The portion of the second part 32 that contacts the third sealing ring 43 may also be provided with a first concave-convex structure 321, further improving sealing performance while increasing the strength of the pole post 30.
  • the strength of the electrode post 30 is significantly improved, and the connection area between the second sealing ring 42 and the electrode post 30 is increased, resulting in stronger sealing performance. Therefore, the length of the second part 32 can be reduced, the space occupied by the electrode post 30 can be reduced, and the energy density of the secondary battery 100 can be further improved.
  • the length of the second part 32 is L2 , 0.5mm ⁇ L2 ⁇ 5mm , which improves the sealing performance while increasing the energy density of the secondary battery 100.
  • the length of the first part 31 is L1 , 0.1mm ⁇ L1 ⁇ 3mm ; and the length of the third part 33 is L3 , 0.1mm ⁇ L3 ⁇ 3mm , which reduces the deformation and skew of the first part 31 and the third part 33, and improves the sealing performance.
  • the depth of the first hole 34 if the depth is too small, it will be difficult to weld the electrode post 30, which may lead to unstable electrical connection between the electrode post 30 and the electrode assembly 20. If the depth of the first hole 34 is too large, the first part 31 may be too thin, reducing its strength. As the part that is electrically connected to the electrode assembly 20, reduced strength of the first part 31 may cause damage and breakage at the connection between the electrode post 30 and the electrode assembly 20.
  • the depth D of the first hole 34 is selected as L3 + L2 /2 ⁇ D ⁇ L3 + L2 . This not only facilitates the penetration welding of the electrode post 30 and the electrode assembly 20, improving the connection strength, but also gives the first part 31 of the electrode post 30 higher strength, reducing damage and breakage at the connection between the electrode post 30 and the electrode assembly 20.
  • the projection of the first wall portion 12 along the first direction X overlaps with the first hole 34, so as to facilitate the electrical connection between the pole post 30 and the electrode assembly 20 and to enable the pole post 30 to have higher strength.
  • the first hole 34 has a bottom wall 341.
  • the bottom wall 341 is positioned opposite the opening, and is located on the side of the first wall portion 12 away from the third portion 33.
  • the welding equipment can directly act on the bottom wall 341 at the first hole 34 to perform penetration welding.
  • the difficulty of penetration can be reduced, and sufficient space is reserved in the first hole 34 to facilitate the electrical connection between the electrode post 30 and the electrode assembly 20, improving the connection strength. Simultaneously, this gives the electrode post 30 higher strength to reduce deformation.
  • the aforementioned first concave-convex structure 321 not only improves the strength of the electrode post 30 and reduces its riveting deformation, but also increases the connection area between the second sealing ring 42 and the second electrode post 30, improving sealing performance. Simultaneously, due to the increased strength and improved sealing performance of the electrode post 30, its length can be reduced, decreasing the space it occupies and thus increasing the energy density of the secondary battery 100. Furthermore, a first hole 34 can be provided in the third portion 33 of the electrode post 30, facilitating electrical connection between the electrode post 30 and the electrode assembly 20 without requiring pre-reserved operating space for electrical connection, further improving the energy density of the secondary battery 100.
  • the second sealing ring 42 is bonded between the second portion 32 and the housing 10, which can improve the bonding strength between the housing 10 and the second portion 32 and reduce the skew deformation of the pole post 30.
  • the first sealing ring 41 is bonded between the first portion 31 and the first wall surface 121 of the housing 10
  • the third sealing ring 43 is bonded between the third portion 33 and the second wall surface 122 of the housing 10, further improving the bonding strength between the pole post 30 and the housing 10, reducing the deformation of the pole post 30, and thus improving the sealing performance.
  • the second sealing ring 42 is provided with a second concave-convex structure 421, which is adapted to the first concave-convex structure 321.
  • the second concave-convex structure 421 can directly fit with the first concave-convex structure 321, thereby fully filling the gap between the second part 32 and the housing 10, and increasing the connection area between the second sealing ring 42 and the second part 32, thereby improving the sealing performance between the pole post 30 and the housing 10.
  • the above-mentioned fitting can be that the shapes and dimensions of the first concave-convex structure 321 and the second concave-convex structure 421 are matched.
  • both the first concave-convex structure 321 and the second concave-convex structure 421 have protruding portions and recessed portions.
  • the protruding portion of the first concave-convex structure 321 fills the recessed portion of the second concave-convex structure 421, and the protruding portion of the second concave-convex structure 421 fills the recessed portion of the first concave-convex structure 321, which can be regarded as fitting.
  • the above-mentioned matching can mean that the shapes and dimensions are consistent or approximately consistent.
  • the first concave-convex structure 321 can be an external thread provided on the outer surface of the second portion 32
  • the second concave-convex structure 421 can be an internal thread provided on the second sealing ring 42.
  • the second sealing ring 42 can be directly threadedly connected to the second portion 32.
  • the second sealing ring 42 can be sleeved on the outer surface of the second portion 32, and then the second sealing ring 42 can be rotated to make the second sealing ring 42 threadedly connected to the second portion 32.
  • the installation operation is convenient and quick.
  • the pole post 30 is placed at the first through hole 13 of the first wall portion 12, and the first portion 31, the second portion 32, and the third portion 33 are formed by riveting.
  • the second portion 32 is tightened with the inner wall of the first hole 34, so that the second sealing ring 42 fully fills the gap between the second portion 32 and the housing 10, thereby improving the sealing performance.
  • the external thread protrudes on the second part 32, and the second sealing ring 42 can be press-fitted with the second part 32.
  • the press-fit can fully fill the gap between the second sealing ring 42 and the second part 32, thereby improving the sealing performance.
  • the first sealing ring 41 may be integrally formed with the second sealing ring 42, and during installation, the second sealing ring 42 may be directly placed into the first through hole 13 from the inner cavity 11 of the housing 10; or, the second sealing ring 42 may be integrally formed with the third sealing ring 43, and during installation, the second sealing ring 42 may be directly placed into the first through hole 13 from the outside of the housing 10.
  • the first sealing ring 41, the second sealing ring 42, and the third sealing ring 43 may be integrally formed, and by utilizing the flexibility of each sealing ring, after the housing 10 compresses the first part 31, the first part 31 may be directly placed into the inner cavity 11 of the housing 10, and the second part 32 may be located at the first through hole 13.
  • first sealing ring 41, the second sealing ring 42, and the third sealing ring 43 can be set separately.
  • the second sealing ring 42 can be first arranged around the second part 32, the first sealing ring 41 can be arranged between the first part 31 and the first wall surface 121 during riveting, and the third sealing ring 43 can be arranged between the third part 33 and the second wall surface 122.
  • the first convex-concave structure 321 includes a first protrusion 3211, the provision of the first protrusion 3211 makes the second portion 32 stronger.
  • a recess is formed between two adjacent first protrusions 3211, and the aforementioned third sealing ring 43 can be embedded in the recess, thereby increasing the connection area between the third sealing ring 43 and the second portion 32.
  • the first protrusion 3211 can be triangular, rectangular, or trapezoidal, etc.
  • the first protrusion 3211 has a bottom 3213 near the first hole 34 and a top 3212 away from the first hole 34.
  • the width of the bottom 3213 is W1
  • the width of the top 3212 is W2 , where W2 ⁇ W1 .
  • the width of the top 3212 can be set to be larger to improve the strength of the second part 32 and its resistance to deformation.
  • a smaller width of the top 3212 facilitates the embedding of the second sealing ring 42 between two adjacent first protrusions 3211, facilitating the filling of the gap between the pole post 30 and the second sealing ring 42, and improving sealing performance.
  • the aforementioned first direction X, second direction Y, and third direction Z are all perpendicular to each other.
  • 0.1mm ⁇ W 1 ⁇ 1mm can not only improve the strength of the second part 32, but also facilitate the embedding of the second sealing ring 42 and the first concave-convex structure 321, thereby improving the sealing performance.
  • the second sealing ring 42 will be difficult to install on the second part 32; if the height of the first protrusion 3211 is too small, the connection area will be small, which is not conducive to improving the sealing performance.
  • the distance from the bottom 3213 to the top 3212 along the first direction X is H, 0.1mm ⁇ H ⁇ 1mm. This facilitates the installation of the second sealing ring 42 while ensuring sufficient engagement between the second sealing ring 42 and the first concave-convex structure 321, increasing the connection area and thus improving the sealing performance.
  • the second part 32 is disposed in the first through hole 13.
  • the second part 32 serves as a connector between the inner first part 31 and the outer third part 33, and its strength also affects the deformation resistance of the electrode post 30.
  • the electrode post 30 adopts a hollow structure, and the first hole 34 enables electrical connection between the electrode post 30 and the electrode assembly 20 outside the housing 10.
  • the thickness of the second portion 32 is T, 0.5mm ⁇ T ⁇ 2mm.
  • the hollow structure of the electrode post 30 can also have high strength, sufficient to reduce deformation or skewing of the electrode post 30, and the hollow structure of the electrode post 30 makes electrical connection between the electrode post 30 and the electrode assembly 20 more convenient. It should be noted that the thickness of the second portion 32 mentioned above does not include the first concave-convex structure 321.
  • a second aspect of this application also provides an electronic device including the secondary battery 100 described in any embodiment of the first aspect.
  • the electronic device in this application is not particularly limited and can be any electronic device known in the prior art.
  • electronic devices include, but are not limited to, Bluetooth headsets, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc.
  • Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.
  • spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.
  • Lithium iron phosphate (LiFePO4), acetylene black (Acetylene Black), and polyvinylidene fluoride (PVDF, weight-average molecular weight 5 ⁇ 105 ) were mixed in a mass ratio of 94:3:3.
  • NMP N-methylpyrrolidone
  • An 8 ⁇ m thick aluminum foil was selected as the positive electrode current collector, and the foil was cut to create inner tabs.
  • the positive electrode slurry was uniformly coated onto one surface of the aluminum foil and dried at 110°C to obtain a positive electrode sheet with a single-sided coating of positive active material (80 ⁇ m thick). The above steps were then repeated on the other surface of the aluminum foil to obtain a positive electrode sheet with a double-sided coating of positive active material.
  • Graphite powder negative electrode active material
  • conductive carbon black Super P
  • styrene-butadiene rubber binder
  • Deionized water was then added as a solvent to prepare a negative electrode slurry with a solid content of 50 wt%, and the mixture was stirred thoroughly.
  • a 5 ⁇ m thick copper foil was selected as the negative electrode current collector, and the inner tabs of the copper foil were cut out.
  • the negative electrode slurry was uniformly coated onto one surface of the copper foil and dried at 90°C to obtain a single-sided negative electrode sheet with a negative electrode active material weight of 9.1 mg/cm2. This completes the single-sided coating of the negative electrode sheet.
  • the above steps were then repeated on the other surface of the negative electrode sheet to obtain a double-sided coated negative electrode sheet.
  • a porous polyethylene (PE) film with a thickness of 8 ⁇ m was used as the separator.
  • ethylene carbonate, methyl ethyl carbonate and diethyl carbonate are mixed in a mass ratio of 30:50:20 to obtain an organic solution.
  • lithium hexafluorophosphate is added to the organic solvent to dissolve and mix evenly to obtain an electrolyte with a lithium salt concentration of 1.15 mol/L.
  • the separator, positive electrode, separator, and negative electrode prepared above are stacked in sequence and wound to obtain an electrode assembly.
  • the electrode assembly is then hot-pressed at a pressure of 5 MPa, a temperature of 65°C, and a holding time of 10 s.
  • the electrode assembly is placed in a steel housing with a first through hole.
  • a hollow electrode post is used, and the electrode post is positioned at the first through hole in the housing.
  • One end of the electrode post extends beyond the first through hole and is located inside the housing, while the other end extends beyond the first through hole and is located outside the housing.
  • the portion of the electrode post located within the first through hole has a first uneven structure, while the portion outside the housing has the first hole.
  • a sealing ring is fitted onto the electrode post, extending from inside the housing to the outside.
  • the ends of the electrode post are riveted and flattened using a riveting device, forming a first, second, and third part.
  • the second part is 5mm long (refer to the length along the third direction Z in Figure 4), the first part is 0.5mm long, and the third part is 0.8mm long.
  • the sealing ring between the first part and the housing is the first sealing ring
  • the sealing ring between the second part and the housing is the second sealing ring
  • the sealing ring between the third part and the housing is the third sealing ring.
  • Laser penetration welding is used to weld the electrode post to the inner tab of the positive electrode at the first hole, and the housing is directly connected to the inner tab of the negative electrode. After removing moisture at 80°C, electrolyte is injected and the electrode is sealed.
  • the pole post does not have a first hole or a first concave-convex structure.
  • Drop test method The lithium-ion battery was pretreated at 25°C and left to stand at room temperature for 60 minutes. The voltage of the lithium-ion battery before the drop test was measured. The lithium-ion battery was placed in a fixture and dropped freely from a height of 1.5m on the ground using a drop device in the following order: head-tail-right corner of head-right corner of tail-left corner of head-left corner of tail (angle: 45 ⁇ 15°), repeated 6 times. After the drop test, the battery was left to stand at room temperature for 24 hours. The appearance of the top terminal of the lithium-ion battery was checked and photographed before and after the test.
  • test pass criteria were: no smoke or leakage at the top terminal, and the connection between the terminal and the positive inner tab of the lithium-ion battery was undamaged and unbroken when disassembled. 20 lithium-ion batteries were tested, and the number of batteries that failed the test was X, with a failure rate of X/20. The test results are shown in Table 1 below.
  • the first concave-convex structure makes the electrode post stronger, reducing deformation and tilting of the electrode post when the lithium-ion battery is impacted, thereby reducing the gap caused by deformation and tilting, and thus reducing the risk of battery leakage.
  • Comparative Example 1 the absence of a first hole hinders the electrical connection between the electrode post and the inner positive electrode tab, making it difficult to increase the connection area and resulting in low connection strength. Furthermore, a large space is required for electrical connection operations within the lithium-ion battery casing. This reserved space may be used for electrode assembly movement, making the connection between the electrode post and the inner positive electrode tab prone to damage or breakage during drop tests. The reserved space also affects the energy density of the lithium-ion battery. Comparative Example 1 also lacks a first concave-convex structure, resulting in lower electrode post strength and susceptibility to deformation. Deformation of the electrode post during impact increases the installation gap between the electrode post and the casing, leading to a higher impact failure rate. Additionally, the small connection area between the electrode post and the sealing ring results in poor sealing, increasing the risk of leakage and smoke during drop tests.
  • Comparative Example 2 only the first hole is provided without the first concave-convex structure. This results in lower pole strength, making it prone to deformation. Upon impact, the deformation of the pole increases the installation gap between the pole and the housing, leading to a higher failure rate. Furthermore, the connection area between the pole and the sealing ring is small, resulting in poor sealing.
  • a first concave-convex structure is provided but a first hole is not provided. It is difficult to electrically connect the electrode post and the inner tab of the positive electrode. Space needs to be reserved in the casing for the electrical connection between the electrode post and the inner tab of the positive electrode. The electrical connection operation is inconvenient, which not only affects the energy density of the lithium-ion battery, but also reduces the connection area, causing damage and breakage at the connection between the electrode post and the inner tab of the positive electrode.
  • the strength of the electrode post is improved, and the connection area between the second sealing ring and the electrode post is increased, resulting in stronger sealing performance.
  • the length of the second part can be reduced to reduce the space occupied by the electrode post, thereby improving the energy density of the lithium-ion battery.
  • the setting of the first hole eliminates the need to reserve additional space for the electrical connection between the electrode post and the inner tab of the positive electrode, which can further improve the energy density of the lithium-ion battery.
  • Example 7 the risk of drop failure is lower than that of Example 7. This may be because in Example 7, the electrode length is too short, which may reduce the connection area and have little effect on improving sealing performance.
  • the risk of drop failure is the same as that of Example 1, but in Example 1, the electrode is shorter and occupies less space, allowing the lithium-ion battery of Example 1 to have a higher energy density. Therefore, in this application, the length L2 of the second part of the electrode can be selected as 0.5mm ⁇ L2 ⁇ 5mm.

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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)
  • Materials Engineering (AREA)
  • Sealing Battery Cases Or Jackets (AREA)
  • Connection Of Batteries Or Terminals (AREA)

Abstract

本申请涉及一种二次电池及电子设备，包括壳体、极柱以及密封组件。极柱包括第一部分、第二部分以及第三部分。第一部分设置于壳体内，第二部分一端与第一部分连接，另一端自壳体的第一通孔伸出壳体外，第三部分于壳体外与第二部分连接。极柱还包括第一孔，第一孔的开口位于第三部分的背离所述第二部分的表面，第二部分的外表面设置有第一凹凸结构。密封组件包括第一密封圈、第二密封圈以及第三密封圈，密封组件的第一密封圈设置于壳体的第一壁面与第一部分之间，第二密封圈环绕第二部分设置，第三密封圈设置于第二壁面与第三部分之间。本申请提供的二次电池及电子设备，可以改善二次电池极柱强度不高易变形以致于密封性较差的技术问题。

Description

二次电池及电子设备
相关申请的交叉参考
本申请要求于2024年5月20日提交中国专利局，申请号为202410674438.1，发明名称为“二次电池及电子设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电池技术领域，特别是涉及一种二次电池及电子设备。
背景技术
二次电池作为移动设备的电源之源是保证移动设备正常使用的关键，同时移动设备例如手机、笔记本电脑等设备普及度越来越高，终端用户对二次电池的大容量和续航要求也越来越高。硬壳二次电池相比软包二次电池，可以设计达到更高的容量。
发明内容
传统的硬壳二次电池需要设置极柱，极柱需要与二次电池内部电极组件的极耳焊接连接，以引出极性。本申请发明人通过研究发现，在极柱与内部极耳焊接的过程中，需要对二次电池的壳体预留较大的空间，以实现极柱与极耳的焊接操作。然而，壳体的空间有限，焊接操作不便，易导致极柱与极耳之间的连接强度不佳，并且预留较大的空间会导致二次电池的能量密度降低。本申请发明人将极柱设置为中空极柱，也即在极柱的外表面设置开孔，在壳体外，可直接在开孔处采用穿透焊实现极柱与极耳的电连接，不需要预留额外的空间，可提高二次电池的能量密度，并且操作更为简单方便，有利于提高极柱与极耳之间的连接强度。然而，中空极柱的设置，使得极柱的强度减弱，在极柱压紧铆合时，极柱与密封圈易发生变形错位，导致密封性变差。
本申请的目的在于提供一种二次电池及电子设备，旨在改善二次电池极柱强度不高易变形以致于密封性较差的技术问题。
根据本申请的第一方面，提供一种二次电池，包括壳体、极柱以及密封组件。壳体包括开设有第一通孔的第一壁部，第一壁部包括相对设置的第一壁面和第二壁面，第一壁面面向壳体的内腔。极柱包括第一部分、第二部分以及第三部分。第一部分设置于壳体内，第二部分一端与第一部分连接，另一端自第一通孔伸出壳体外，第三部分于壳体外与第二部分连接。极柱还包括第一孔，第一孔的开口位于第三部分的背离第二部分的表面，第二部分的外表面设置有第一凹凸结构。密封组件包括第一密封圈、第二密封圈以及第三密封圈，第一密封圈设置于第一壁面与第一部分之间，第二密封圈环绕第二部分设置，第三密封圈设置于第二壁面与第三部分之间。
上述技术方案中，在第三部分的外表面开设有第一孔，焊接设备可在第一孔处实现对极柱与电极组件的电连接，不需要在壳体内预留空间，不仅操作方便，还可提高二次电池的能量密度。并且，因极柱与电极组件的电连接操作更为简单方便，可便于提高极柱与电极组件的连接强度。
同时，第一凹凸结构的设置提高了极柱第二部分的强度，可减少第二部分的变形，进而减少极柱与密封圈之间的间隙，提高二次电池的密封性能。并且，第一凹凸结构的设置可增大第二密封圈与第二部分的连接面积，进一步提高了第二密封圈与极柱之间的密封性能。
另外，因上述第一凹凸结构的设置，提高了极柱的强度，以及第二密封圈与极柱的连接面积增大，密封性能更强。因此，可减小第二部分的长度，减小极柱所占用的空间，进一步提高二次电池的能量密度。
在一些优选的实施方式中，沿第一方向，第一凹凸结构的投影与第一孔重叠，第一凹凸结构分布在第一孔的外侧，减少第一孔对极柱强度的影响。
在一些优选的实施方式中，沿第一方向，第一壁部的投影与第一孔重叠，以便于极柱与电极组件的电连接。
在一些优选的实施方式中，第一孔具有底壁，沿第一壁面至第二壁面的方向，底壁与开口相对设置，第一孔的底壁位于第一壁部的背离第三部分的一侧，预留足够的空间，以便于极柱与电极组件的电连接，提高连接强度。
在一些优选的实施方式中，第二密封圈设置有第二凹凸结构，第二凹凸结构与第一凹凸结构相嵌合，可充分填充第二部分与壳体之间的间隙，并可增大第二密封圈与第二部分的连接面积，提高极柱与壳体之间的密封性能。
在一些优选的实施方式中，第一凹凸结构为设置于第二部分外表面的外螺纹，第二凹凸结构为设置于第二密封圈的内螺纹，第二密封圈与第二部分螺纹连接。通过旋转第二密封圈即可使得第二密封圈与第二部分螺纹连接，安装操作方便快捷。
在一些优选的实施方式中，二次电池还包括垫圈，垫圈设置于第三部分与第三密封圈之间。垫圈可隔绝第三部分与第三密封圈，减少铆压时第三部分对第三密封圈的直接压接损坏。
在一些优选的实施方式中，沿第一壁面至第二壁面的方向，第一部分的长度为L1，0.1mm≤L1≤3mm；第二部分的长度为L2，0.5mm≤L2≤5mm；
第三部分的长度为L3，0.1mm≤L3≤3mm。适应性减小第二部分的长度，减小极柱所占用的空间，进而提高二次电池的能量密度。
在一些优选的实施方式中，沿第一壁面至第二壁面的方向，第三部分的长度为L3，第二部分的长度为L2，第一孔的深度为D，L3+L2/2≤D≤L3+L2。不仅便于极柱与电极组件焊接，提高连接强度，同时使得极柱的第一部分具有较高的强度，减少极柱与电极组件连接处的破损断裂。
在一些优选的实施方式中，极柱包括铝、铜或铝合金中至少一种，具有良好的导电性、导热性、耐腐蚀性等，可加工性强，便于极柱的铆压密封。
在一些优选的实施方式中，第一部分、第二部分以及第三部分一体设置。三个部分之间不存在连接间隙，提高密封性能，并且一体设置强度更大，在铆压后，其抗变形能力更强，可减少因变形而产生的安装间隙，进而提高密封性能。
在一些优选的实施方式中，第一凹凸结构包括第一凸部，第一凸部具有靠近第一孔的底部以及远离第一孔的顶部。沿第一壁面至第二壁面的方向，底部的宽度为W1，顶部的宽度为W2，W2≤W1。顶部的宽度可设置得更大，便于提高第二部分的强度，提高第二部分的抗变形能力。顶部的宽度更小，便于第二密封圈嵌入至相邻两个第一凸部之间，提高密封性能。
在一些优选的实施方式中，0.1mm≤W1≤1mm。
在一些优选的实施方式中，底部至顶部的距离为H，0.1mm≤H≤1mm。可在便于第二密封圈安装的同时，方便第二密封圈与第一凹凸结构的充分啮合，提高链接面积，进而提高密封性能
在一些优选的实施方式中，所沿第一孔至第一凹凸结构的方向，第二部分的厚度为T，0.5mm≤T≤2mm，可减少极柱变形或歪斜，并且中空结构的设置使得极柱与电极组件的电连接更为便利。
第二方面，本申请还提出了一种电子设备，包括如上述第一方面任一实施例的二次电池。
本申请实施例的额外层面及优点将部分地在后续说明中描述、显示、或是经由本申请实施例的实施而阐释。
附图说明
一个或多个实施例通过与之对应的附图进行示例性说明，这些示例性说明并不构成对实施例的限定，附图中具有相同参考数字标号的元件表示为类似的元件，除非特别申明，附图中的尺寸不构成比例限制。
图1为本申请一些实施例的二次电池的结构示意图；
图2为本申请一些实施例的壳体的结构示意图；
图3为本申请一些实施例的二次电池的结构示意图；
图4为本申请一些实施例的极柱铆压结构的部分示意图；
图5为本申请一些实施例的极柱铆压结构的部分爆炸示意图；
图6为本申请一些实施例的二次电池的结构示意图；
图7为图5中A处的局部放大图。
附图标记说明：
100、二次电池；
10、壳体；11、内腔；12、第一壁部；121、第一壁面；122、第二壁面；13、
第一通孔；
20、电极组件；21、极耳；
30、极柱；31、第一部分；32、第二部分；321、第一凹凸结构；3211、第一
凸部；3212、顶部；3213、底部；33、第三部分；34、第一孔；341、底壁；
40、密封组件；41、第一密封圈；42、第二密封圈；421、第二凹凸结构；43、
第三密封圈；
50、垫圈；
X、第一方向；Y、第二方向；Z、第三方向。
具体实施方式
为使本申请实施例的目的、技术方案和优点更加清楚，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。
在本申请中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。
在本申请实施例的描述中，技术术语“第一”“第二”等仅用于区别不同对象，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量、特定顺序或主次关系。在本申请实施例的描述中，“多个”的含义是两个以上，除非另有明确具体的限定。
在本申请实施例的描述中，术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
下面所描述的本申请不同实施例中所涉及的技术特征只要彼此之间未构成冲突就可以相互结合。
本申请的第一方面，提出了一种二次电池100，请参照图1，二次电池100包括壳体10、电极组件20、极柱30以及密封组件40。电极组件20设置于壳体10内，极柱30的一端与电极组件20电连接，另一端伸出壳体10外，密封组件40设置于极柱30与壳体10之间，用于绝缘分隔极柱30与壳体10，以及用于密封极柱30与壳体10之间的安装间隙。
对于上述壳体10，请参照图1和图2，壳体10围合有内腔11，二次电池100还包括电极组件20及电解液(未在图中示出)，电极组件20及电解液均可收容于内腔11。壳体10包括第一壁部12，第一壁部12位于壳体10的顶部并覆盖壳体10的内腔11。第一壁部12包括相对设置的第一壁面121和第二壁面122，第一壁面121面向壳体10的内腔11，第二壁面122背离壳体10的内腔11。第一壁部12开设有第一通孔13，第一通孔13贯穿第一壁面121以及第二壁面122，第一通孔13与壳体10的内腔11相通，上述极柱30可安装于第一通孔13处。
本申请的实施例中，二次电池100可采用硬壳二次电池100，壳体10可采用一层金属片冲裁成型的结构，例如采用一层钢片冲裁成型，可提高壳体10的强度，提高壳体10的抗变形能力。在其他一些实施例中，壳体10还可采用不锈钢、镍或铜等金属材料。相较于软包二次电池100，本申请中的硬壳二次电池100可以设计达到更高的容量，便于满足二次电池100的大容量和长续航的设计要求。
对于上述电极组件20，请参照图1，电极组件20设置于壳体10的内腔11，上述电解液可在壳体10的内腔11中浸润电极组件20，以实现电化学反应。电极组件20可采用叠片式结构，电极组件20包括正极极片(未在图中示出)、负极极片(未在图中示出)以及隔离膜(未在图中示出)，若干正极极片以及若干负极极片交替层叠设置，隔离膜设置于正极极片与负极极片之间，以绝缘分隔二者。
在其他一些实施例中，电极组件20还可采用卷绕式结构，也即正极极片、隔离膜以及负极极片层叠后卷绕设置，以形成卷绕式电极组件20。
对于上述极柱30，极柱30作为与外部电路连接的“桥梁”，负责将二次电池100内部产生的电流导出至外部电路，以及将外部电流导入至二次电池100内部。极柱30可设置于上述壳体10的第一通孔13，并且极柱30的一端于壳体10的内腔11中与电极组件20电连接，例如与电极组件20的极耳21连接，另一端则伸出壳体10外，用于连接外部电路，以实现二次电池100的充放电。其中，极耳21可采用片状、板状、盘状或柱状等，能够电连接极柱30即可。
本申请的实施例中，壳体10采用金属壳体10，金属壳体10本身可导电，可将金属壳体10作为二次电池100的正极或负极。例如，极柱30作为二次电池100的正极，与上述电极组件20的正极极片电连接，壳体10则作为负极，电极组件20的负极极片与壳体10直接电连接；极柱30作为负极时，则壳体10可作为正极。在其他一些实施例中，也可采用至少两个极柱30，至少一个极柱30作为二次电池100的正极，至少一个极柱30作为二次电池100的负极。
极柱30可采用铆压结构，请参照图2和图3，极柱30包括第一部分31、第二部分32以及第三部分33。第一部分31设置于壳体10内，第一部分31与上述电极组件20电连接，例如通过上述极耳21与上述电极组件20的正极极片或负极极片电连接。第二部分32一端与第一部分31连接，另一端自第一通孔13伸出壳体10外。第三部分33于壳体10外与第二部分32连接，第三部分33用于电连接外部电路。
可选的，安装时，极柱30整体呈柱状，可首先将极柱30置于第一通孔13中，再对极柱30的两端进行铆压，并使得两端压平，以形成上述第一部分31、第二部分32以及第三部分33。在铆压后，沿第一方向X，第一部分31和第三部分33的宽度均大于第二部分32的宽度，第一部分31和第三部分33将第二部分32夹设，可减少极柱30从壳体10上脱出。
在一些实施例中，第一部分31、第二部分32以及第三部分33一体设置，三个部分之间不存在连接间隙，提高密封性能，并且一体设置强度更大，在铆压后，其抗变形能力更强，可减少因变形而产生的安装间隙，进而提高密封性能。
在一些实施例中，极柱30包括铝、铜或铝合金等中的至少一种。示例性的，极柱30采用铝，铝材质的极柱30具有良好的导电性、导热性、耐腐蚀性以及延展性等，可加工性强，便于极柱30的铆压密封，在铆压时，铝材质的极柱30可轻微压缩，从而可填充极柱30与密封组件40之间的间隙，提高密封性能。
对于上述密封组件40，密封组件40设置于极柱30与壳体10之间，用于密封极柱30与壳体10之间的安装间隙，以密封壳体10的内腔11；当极柱30与壳体10分别作为二次电池100的正负极时，密封组件40也可绝缘分隔极柱30与壳体10。
请参照图3，密封组件40包括第一密封圈41、第二密封圈42以及第三密封圈43。第一密封圈41设置于第一壁面121与第一部分31之间，用于分隔第一部分31与壳体10。第二密封圈42环绕第二部分32设置，用于分隔第二部分32与壳体10。第三密封圈43设置于第二壁面122与第三部分33之间，用于分隔第三部分33与壳体10。
其中，第一密封圈41、第二密封圈42以及第三密封圈43可采用聚丙烯(PP)、聚乙烯(PE)、聚苯乙烯(PS)、聚氯乙烯(PVC)、聚对苯二甲酸乙二醇酯(PET)、聚酰胺(PA)或酚醛树脂(PF)中的至少一种。示例性的，采用酚醛树脂，使得上述各密封圈具有较佳的耐热性以及电绝缘性。
在一些实施例中，请参照图3至图4，二次电池100还包括垫圈50，垫圈50设置于第三部分33与第三密封圈43之间。在铆压极柱30时，垫圈50可隔绝第三部分33与第三密封圈43，减少铆压时第三部分33对第三密封圈43的直接压接损坏。其中，垫圈50可采用金属垫圈50，例如采用不锈钢、碳钢或铜等金属材料，适用于高压等工况。
在其他一些实施例中，垫圈50也可采用橡胶、塑料或者聚四氟乙烯等。可选的，第一部分31与第一密封圈41之间也可设置垫圈50，减少第一部分31对第一密封圈41的直接压接损坏，提高密封组件40的完整性。
在一些实施例中，极柱30可采用中空结构，请参照图3，极柱30还包括第一孔34，第一孔34的开口位于第三部分33的背离第二部分32的表面。其中，第一孔34可贯穿第三部分33，或者，第一孔34自第三部分33延伸于第二部分32内，或者第一孔34同时贯穿第三部分33和第二部分32，再或者第一孔34贯穿第三部分33、第二部分32并延伸于第一部分31内。
中空结构的极柱30可便于从壳体10的外部实现对极柱30与电极组件20的电连接，电连接方式包括但不限于焊接、导电胶粘接或卡接等。示例性的，以焊接为例，焊接设备在壳体10外并自伸入极柱30的第一孔34，通过将电极组件20的极耳21(极耳与正极极片或负极极片电连接，作为连接的转接件)抵靠在极柱30的下端，然后进行激光穿透焊接即可使得极柱30与极耳焊接固定。不需要在壳体10内预留空间，不仅操作方便，还可提高二次电池100的能量密度。同时，因极柱30与电极组件20的电连接操作更为简单方便，可便于极柱30与电极组件20的连接强度。焊接方式并不限于激光焊接，还可采用超声波焊接或电子束焊接等。
在一些实施例中，请进一步参照图4和图5(图5中为极柱30铆压结构的部分爆炸示意图，各密封圈仅示出了部分)，第二部分32的外表面设置有第一凹凸结构321，第一凹凸结构321的设置提高了第二部分32的强度，可减少第二部分32的变形，例如减少极柱30的铆压或者碰撞变形等，进而减少因极柱30变形而产生的安装间隙，可提高第二密封圈42与极柱30之间的密封性能。因极柱30的第二部分32设置有第一凹凸结构321，使得极柱30的强度更高，其抗变形能力更强，即使采用中空结构，极柱同样具有较高的强度。
在一些实施例中，沿第一方向X，第一凹凸结构321的投影与第一孔34重叠，第一凹凸结构321分布在第一孔34的外侧，减少第一孔34对极柱30强度的影响。需要说明，极柱30设置有第一孔34的部分，其强度较弱，而未设置第一孔34的部分，仍具有较高的强度。本实施例中，可仅在极柱30设置有第一孔34的外侧设置第一凹凸结构321，减少第一孔34对极柱30强度的影响，而未设置第一孔34的部分(例如第一部分31或第二部分32中第一孔34未到达的部分)无需设置第一孔34，减少第一凹凸结构321所占用减少，减少对二次电池100能量密度的影响。
其中，第一方向X与第一壁面121至第二壁面122的方向(第三方向Z)垂直。再例如，第一方向X、第二方向Y以及第三方向Z两两相互垂直；沿第二方向Y，第一凹凸结构321的投影也与第一孔34重叠。
上述第一密封圈41、第二密封圈42以及第三密封圈43均可采用柔性材质，以充分填充极柱30与壳体10之间的安装间隙。当第二密封圈42环绕设置于第二部分32上时，第二密封圈42可填充第一凹凸结构321，并与第一凹凸结构321相配合，第一凹凸结构321的设置可增大第二密封圈42与第二部分32的连接面积，可进一步提高第二密封圈42与极柱30之间的密封性能。
第一凹凸结构321可以是在第二部分32外表面凸出的凸起部和/或凹陷的凹陷槽，凹凸不平的设置提高了第二部分32与第二密封圈42之间的摩擦力并增大了第二部分32与第二密封圈42之间的连接面积，其密封性能更强。
在其他一些实施例，第二部分32与第二密封圈42接触的部分均可设置第一凹凸结构321，进而增加第二部分32与第二密封圈42之间的连接面积，接触面积更大则密封性能更强。因第三密封圈43设置于第二壁面122与第三部分33之间，因此第三密封圈43也可能与第二部分32接触，第二部分32与第三密封圈43接触的部分也可设置第一凹凸结构321，进一步提高密封性能的同时，提高极柱30强度。
另外，因上述第一凹凸结构321的设置，极柱30的强度得到显著提高，以及第二密封圈42与极柱30的连接面积增大，密封性能更强，因此可减小第二部分32的长度，减小极柱30所占用的空间，进一步提高二次电池100的能量密度。例如，沿第一壁面121至第二壁面122的方向(第三方向Z)，第二部分32的长度为L2，0.5mm≤L2≤5mm，在提高密封性能的同时提高二次电池100的能量密度。其中，第一部分31的长度为L1，0.1mm≤L1≤3mm；以及，第三部分33的长度为L3，0.1mm≤L3≤3mm，减少第一部分31与第三部分33的变形歪斜，提高密封性能。
而对于上述第一孔34的深度，第一孔34的深度过小，难以对极柱30进行焊接，可能导致极柱30与电极组件20的电连接不稳定；而第一孔34的深度过大，则可能导致第一部分31过薄，使得第一部分31强度降低，而第一部分31作为与电极组件20电连接的部件，强度降低可能导致极柱30与电极组件20的连接处易发生破损断裂。本申请的实施例中，请参照图3和图4，第一孔34的深度D选择L3+L2/2≤D≤L3+L2，不仅便于极柱30与电极组件20穿透焊接，提高连接强度，同时使得极柱30的第一部分31具有较高的强度，减少极柱30与电极组件20连接处的破损断裂。
在一些实施例中，请进一步参照图6，沿第一方向X，第一壁部12的投影与第一孔34重叠，以便于极柱30与电极组件20的电连接并可使得极柱30具有较高的强度。
在其他一些实施例中，第一孔34具有底壁341，沿第一壁面121至第二壁面122的方向(第三方向Z)，底壁341与开口相对设置，第一孔34的底壁341位于第一壁部12的背离第三部分33的一侧。以焊接为例，焊接设备可在第一孔34处直接作用于底壁341，以进行穿透焊接，通过将底壁341设置于第一壁部12的背离第三部分33的一侧，可降低穿透难度，并预留足够的第一孔34的空间，以便于极柱30与电极组件20的电连接，提高连接强度，同时使得极柱30具有较高的强度，以减少极柱30的变形。
上述第一凹凸结构321的设置，不仅可提高极柱30的强度，减少极柱30的铆压变形，还可增大第二密封圈42与第二极柱30的连接面积，提高密封性能。同时，因极柱30的强度提高以及密封性能的提高，可减小极柱30长度，减少极柱30所占用空间，进而提高二次电池100的能量密度。以及，可在极柱30的第三部分33设置第一孔34，可方便极柱30与电极组件20的电连接，不需要预留电连接的操作空间，可进一步提高二次电池100的能量密度。
在一些实施例中，第二密封圈42粘接在第二部分32与壳体10之间，可提高壳体10与第二部分32之间的结合强度，减少极柱30歪斜变形。类似的，第一密封圈41粘接于第一部分31与壳体10的第一壁面121之间，第三密封圈43粘接于第三部分33与壳体10的第二壁面122之间，进一步提高极柱30与壳体10的结合强度，减少极柱30变形，进而提高密封性能。
在一些实施例中，请参照图4和图5，第二密封圈42设置有第二凹凸结构421，第二凹凸结构421与第一凹凸结构321相适配，当第二密封圈42套设置第二部分32时，第二凹凸结构421可直接与第一凹凸结构321相嵌合，进而充分填充第二部分32与壳体10之间的间隙，并可增大第二密封圈42与第二部分32的连接面积，提高极柱30与壳体10之间的密封性能。
需要说明的是，上述嵌合可以是第一凹凸结构321与第二凹凸结构421的形状尺寸相匹配，例如第一凹凸结构321和第二凹凸结构421均具有凸起部分与凹陷部分，第一凹凸结构321的凸起部分填充第二凹凸结构421的凹陷部分，第二凹凸结构421的凸起部分填充第一凹凸结构321的凹陷部分即可视为嵌合。上述相匹配可以是指形状尺寸一致或近似一致，当凸起部分填充凹陷部分时，在满足二次电池100整体密封要求的情况下，凸起部分与凹陷部分之间具有微小间隙和/或没有间隙，当具有微小间隙时，该微小间隙被第二密封圈42与第二部分32覆盖。
在一些实施例中，第一凹凸结构321可以是设置于第二部分32外表面的外螺纹，第二凹凸结构421为设置于第二密封圈42的内螺纹，第二密封圈42可直接与第二部分32螺纹连接。安装时，可将第二密封圈42套设在第二部分32的外表面，再通过旋转第二密封圈42使得第二密封圈42与第二部分32螺纹连接，安装操作方便快捷。将极柱30置于第一壁部12的第一通孔13处，通过铆压分别形成上述第一部分31、第二部分32以及第三部分33，铆压时会使得第二部分32与第一孔34的内壁之间收紧，使得第二密封圈42充分填充第二部分32与壳体10之间的间隙，提高密封性能。
外螺纹在第二部分32上凸出，第二密封圈42可与第二部分32过盈配合，当旋转第二密封圈42使得第二密封圈42与第二部分32螺纹连接时，过盈配合可充分填充第二密封圈42与第二部分32之间的间隙，进而提高密封性能。
在一些实施例中，第一密封圈41可与第二密封圈42一体设置，安装时可直接从壳体10内腔11将第二密封圈42设置于第一通孔13；或者，第二密封圈42与第三密封圈43一体设置，安装时可直接从壳体10外将第二密封圈42设置于第一通孔13。或者，第一密封圈41、第二密封圈42以及第三密封圈43一体设置，利用各密封圈的柔性特性，在壳体10压缩第一部分31后可直接将第一部分31设置于壳体10的内腔11，并使得第二部分32位于第一通孔13处。
在其他一些实施例中，也可采用第一密封圈41、第二密封圈42以及第三密封圈43分体设置，可首先将第二密封圈42环绕设置于第二部分32，在铆压时将第一密封圈41设置于第一部分31与第一壁面121之间，以及将第三密封圈43设置第三部分33与第二壁面122之间。
在一些实施例中，请参照图4至图7，第一凹凸结构321包括第一凸部3211，第一凸部3211的设置使得第二部分32的强度更高。相邻两第一凸部3211之间形成有凹陷，上述第三密封圈43可嵌入至凹陷中，进而提高第三密封圈43与第二部分32之间的连接面积。
对于第一凸部3211的形状，沿第二方向Y观察，第一凸部3211可设置三角形、矩形或梯形等。示例性的，以梯形为例，第一凸部3211具有靠近第一孔34的底部3213以及远离第一孔34的顶部3212。沿第一壁面121至第二壁面122的方向，底部3213的宽度为W1，顶部3212的宽度为W2，W2≤W1。顶部3212的宽度可设置得更大，便于提高第二部分32的强度，提高第二部分32的抗变形能力。顶部3212的宽度更小，便于第二密封圈42嵌入至相邻两个第一凸部3211之间，便于填充极柱30与第二密封圈42之间的间隙，提高密封性能。上述第一方向X、第二方向Y、第三方向Z两两相互垂直。
其中，0.1mm≤W1≤1mm，不仅可提高第二部分32的强度，还可便于第二密封圈42与第一凹凸结构321的嵌入，提高密封性能。
对于第一凸部3211的高度，第一凸部3211的高度过大，第二密封圈42难以安装于第二部分32；第一凸部3211的高度过小，连接面积则较小，不利于提高密封性能。本申请中的实施例中，请参照图7，沿第一方向X，底部3213至顶部3212的距离为H，0.1mm≤H≤1mm。可在便于第二密封圈42安装的同时，方便第二密封圈42与第一凹凸结构321的充分啮合，提高链接面积，进而提高密封性能。
第二部分32设置于第一通孔13，第二部分32作为内部第一部分31与外部第三部分33的连接件，其强度的大小也影响着极柱30的抗变形能力。本申请的实施例中，极柱30采用的是中空结构的极柱30，第一孔34的设置可实现在壳体10外对极柱30与电极组件20电连接。
本申请的实施例中，请参照图5，沿第一孔34至第一凹凸结构321的方向(第一方向X)，第二部分32的厚度为T，0.5mm≤T≤2mm。结合第一凹凸结构321，中空结构的极柱30也可具有较高的强度，足以减少极柱30变形或歪斜，并且中空结构的极柱3使得极柱30与电极组件20的电连接更为便利。需要说明的是，上述第二部分32的厚度是不包括第一凹凸结构321的。
本申请的第二方面，还提出了一种电子设备，包括上述第一方面任一实施例所述的二次电池100。本申请实施例的电子设备没有特别限定，其可以是现有技术中已知的任何电子设备。例如，电子设备包括但不限于蓝牙耳机、手机、平板、笔记本电脑、电动玩具、电动工具、电瓶车、电动汽车、轮船、航天器等等。其中，电动玩具可以包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等，航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
实施例1：锂离子电池的制备
<正极极片的制备>：
将正极活性材料磷酸铁锂、正极导电剂乙炔黑、正极粘结剂聚偏二氟乙烯(PVDF，重均分子量为5×105)按照质量比94:3:3进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，在真空搅拌机作用下搅拌至固含量为75wt％且体系均匀的正极浆料。选用厚度为8μm的铝箔作为正极集流体，并对铝箔裁剪出正极内极耳。将正极浆料均匀涂布在正极集流体铝箔的一个表面上，110℃条件下烘干，得到单面涂布正极活性物质层(厚度80μm)的正极极片。之后，在该铝箔的另一个表面上重复以上步骤，得到双面涂布正极活性物质层的正极极片。
<负极极片的制备>
将负极活性材料石墨粉末、导电剂导电炭黑(Super P)、粘结剂丁苯橡胶(SBR)按照重量比97.5:1:1.5进行混合，然后加入去离子水作为溶剂，调配成固含量为50wt％的负极浆料，并搅拌均匀。选用厚度为5μm的铜箔作为负极集流体，并对铜箔裁剪出负极内极耳。将负极浆料均匀涂覆在负极集流体铜箔的一个表面上，90℃条件下烘干，得到负极活性物质重量为9.1mg/cm2单面负极极片。以上步骤完成后，即已完成负极极片的单面涂布。之后，在该负极极片的另一个表面上重复以上步骤，即得到双面涂布负极活性物质层的负极极片。
<隔离膜的制备>
以厚度为8μm的聚乙烯(PE)多孔薄膜作为隔离膜。
<电解液制备>
在干燥氩气气氛中，将碳酸乙烯酯、碳酸甲乙酯和碳酸二乙酯以质量比30:50:20混合得到有机溶液，然后向有机溶剂中加入锂盐六氟磷酸锂溶解并混合均匀，得到锂盐的浓度为1.15mol/L的电解液。
<锂离子电池的制备>
将上述制备得到的隔离膜、正极极片、隔离膜、负极极片按顺序叠好，卷绕得到电极组件，对电极组件进行热压，压力5MPa，温度65℃，保压时间10s。
将电极组件放入开设有第一通孔的钢质壳体中，采用中空结构的极柱，并将极柱置于壳体的第一通孔处，极柱一端超出第一通孔并位于壳体内，另一端超出第一通孔并位于壳体外。其中极柱位于第一通孔的部分上设置有凹凸不平的第一凹凸结构，位于壳体外的部分则开设有第一孔。
对极柱套设密封圈，密封圈延伸自壳体内延伸至壳体外。采用铆压设备对极柱的两端进行铆压并压平，使得极柱形成第一部分、第二部分以及第三部分，其中第二部分的长度为5mm(可参照图4中沿第三方向Z的长度)，第一部分长度为0.5mm，第三部分长度为0.8mm。第一部分与壳体之间的密封圈为第一密封圈，第二部分与壳体之间的密封圈为第二密封圈，第三部分与壳体之间的密封圈为第三密封圈。在第一孔处采用激光穿透焊将极柱与上述正极内极耳焊接，并将壳体与上述负极内极耳直接连接。在80℃下脱去水分后，注入电解液并封装。
对比例1，与实施例1不同的是，极柱未设置第一孔，也未设置第一凹凸结构。
对比例2至3以及实施例2至8的相关参数可参照如下表1。
跌落测试方法：将锂离子电池在25℃下进行预处理，常温环境中静置60min后，测试跌落测试前锂离子电池的电压；将锂离子电池装入夹具中，采用跌落设备按照如下顺序从距离地面1.5m的位置自由跌落：头-尾-头右角-尾右角-头左角-尾左角(角度：45±15°)，重复6次。跌落结束后，常温静置24h，测试前后均检查锂离子电池的顶部极柱处外观并拍照。测试通过判断标准：顶部极柱处不冒烟，不漏液，拆解锂离子电池，极柱与正极内极耳的连接处未破损未断裂。测试20个锂离子电池，未通过测试的电池数量为X个，测试失效率为X/20。测试结果如下表1所示。
表1
根据上述表1，结合实施例1至8以及对比例1至3可知，当采用极柱设置第一凹凸结构以及设置第一孔时，其测试失效率明显降低。这是因为第一凹凸结构的设置可增大第二密封圈与第二部分的连接面积，提高第二密封圈与极柱之间的密封性能，进而减少锂离子电池的漏液风险。并且，第一孔的设置便于从壳体外电连接极柱与正极内极耳，可方便提高极柱与正极内极耳的连接面积，进而提高连接强度，极柱与正极内极耳连接处破损断裂的风险更低。同时，第一凹凸结构的设置使得极柱强度更高，当锂离子电池发生碰撞时，可减少极柱变形歪斜，进而减少因变形歪斜产生的间隙，从而降低电池漏液风险。
对比例1中，未设置第一孔，不便于极柱与正极内极耳的电连接，难以提高极柱与正极内极耳的连接面积，连接强度不高，并且需要预留较大的空间以供在锂离子电池壳体内部进行电连接操作，该预留的空间可能作为电极组件活动的空间，以致于跌落测试时易发生极柱与正极内极耳连接处的破损、断裂，并且预留的空间会影响锂离子电池的能量密度。对比例1中也未设置第一凹凸结构，极柱强度较低，易发生变形，碰撞时极柱的变形则导致极柱与壳体之间安装间隙增大，碰撞失效率较高；并且极柱与密封圈之间的连接面积较小，导致密封性不佳，在跌落测试时，漏液冒烟风险提高。
对比例2中，仅设置有第一孔而未设置第一凹凸结构，极柱强度较低，易发生变形，碰撞时极柱的变形则导致极柱与壳体之间安装间隙增大，碰撞失效率较高。并且，并且极柱与密封圈之间的连接面积较小，密封性较差。
对比例3中，设置有第一凹凸结构而未设置第一孔，极柱与正极内极耳难以电连接，需要在壳体内预留空间以供极柱与正极内极耳的电连接，电连接操作不方便，不仅影响锂离子电池的能量密度，还会导致连接面积减小，导致极柱与正极内极耳的连接处发生破损断裂。
而上述各实施例中，因上述第一凹凸结构的设置，极柱的强度得到提高，以及第二密封圈与极柱的连接面积增大，密封性能更强，可适应性减小第二部分的长度，减小极柱所占用的空间，进而提高锂离子电池的能量密度，以及第一孔的设置，不需要预留额外的空间以供极柱与正极内极耳的电连接，可进一步提高锂离子电池能量密度。
结合实施例1至8，实施例1至6以及实施例8中，跌落失效风险低于实施例7，这可能是因为实施例7中，极柱长度太短，可能导致连接面积减少，对提高密封性能的效果不明显；而实施例8中，其跌落失效风险与实施例1一致，而实施例1中极柱更短，占用空间更小，实施例1的锂离子电池可具有更高的能量密度。因此本申请中，可选择极柱第二部分的长度L2为0.5mm≤L2≤5mm。
以上所述仅为本申请的实施例，并非因此限制本申请的专利范围，凡是利用本申请说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本申请的专利保护范围内。

Claims (17)

  1. 一种二次电池，其特征在于，包括：
    壳体，包括开设有第一通孔的第一壁部，所述第一壁部包括相对设置的第一壁面和第二壁面，所述第一壁面面向所述壳体的内腔；
    极柱，包括第一部分、第二部分以及第三部分，所述第一部分设置于所述壳体内，所述第二部分一端与所述第一部分连接，另一端自所述第一通孔伸出所述壳体外，所述第三部分于所述壳体外与所述第二部分连接；所述极柱还包括第一孔，所述第一孔的开口位于所述第三部分的背离所述第二部分的表面，所述第二部分的外表面设置有第一凹凸结构；
    密封组件，包括第一密封圈、第二密封圈以及第三密封圈，所述第一密封圈设置于所述第一壁面与所述第一部分之间，所述第二密封圈环绕所述第二部分设置，所述第三密封圈设置于所述第二壁面与所述第三部分之间。
  2. 根据权利要求1所述的二次电池，其特征在于，沿第一方向，所述第一凹凸结构的投影与所述第一孔重叠；其中，所述第一方向与所述第一壁面至所述第二壁面的方向垂直。
  3. 根据权利要求1所述的二次电池，其特征在于，沿第一方向，所述第一壁部的投影与所述第一孔重叠。
  4. 根据权利要求3所述的二次电池，其特征在于，所述第一孔具有底壁，沿所述第一壁面至所述第二壁面的方向，所述底壁与所述开口相对设置，所述第一孔的底壁位于所述第一壁部的背离所述第三部分的一侧。
  5. 根据权利要求1所述的二次电池，其特征在于，所述第二密封圈设置有第二凹凸结构，所述第二凹凸结构与所述第一凹凸结构相嵌合。
  6. 根据权利要求1所述的二次电池，其特征在于，所述第一凹凸结构为设置于所述第二部分外表面的外螺纹，所述第二凹凸结构为设置于所述第二密封圈的内螺纹，所述第二密封圈与所述第二部分螺纹连接。
  7. 根据权利要求1所述的二次电池，其特征在于，所述二次电池还包括垫圈，所述垫圈设置于所述第三部分与所述第三密封圈之间。
  8. 根据权利要求1所述的二次电池，其特征在于，沿所述第一壁面至所述第二壁面的方向，所述第二部分的长度为L2，0.5mm≤L2≤5mm。
  9. 根据权利要求1至8中任一项所述的二次电池，其特征在于，沿所述第一壁面至所述第二壁面的方向，
    所述第一部分的长度为L1，0.1mm≤L1≤3mm；
    所述第三部分的长度为L3，0.1mm≤L3≤3mm。
  10. 根据权利要求1所述的二次电池，其特征在于，沿所述第一壁面至所述第二壁面的方向，所述第三部分的长度为L3，所述第二部分的长度为L2，所述第一孔的深度为D，L3+L2/2≤D≤L3+L2。
  11. 根据权利要求1所述的二次电池，其特征在于，所述极柱包括铝、铜或铝合金中至少一种。
  12. 根据权利要求1所述的二次电池，其特征在于，所述第一部分、第二部分以及第三部分一体设置。
  13. 根据权利要求1所述的二次电池，其特征在于，所述第一凹凸结构包括第一凸部，所述第一凸部具有靠近所述第一孔的底部以及远离所述第一孔的顶部；
    沿所述第一壁面至所述第二壁面的方向，所述底部的宽度为W1，所述顶部的宽度为W2，W2≤W1。
  14. 根据权利要求13所述的二次电池，其特征在于，0.1mm≤W1≤1mm。
  15. 根据权利要求13所述的二次电池，其特征在于，所述底部至所述顶部的距离为H，0.1mm≤H≤1mm。
  16. 根据权利要求1所述的二次电池，其特征在于，所沿所述第一孔至所述第一凹凸结构的方向，所述第二部分的厚度为T，0.5mm≤T≤2mm。
  17. 一种电子设备，其特征在于，包括如权利要求1至16中任一项所述的二次电池。
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