WO2020155223A1 - 二次电池 - Google Patents

二次电池 Download PDF

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Publication number
WO2020155223A1
WO2020155223A1 PCT/CN2019/075564 CN2019075564W WO2020155223A1 WO 2020155223 A1 WO2020155223 A1 WO 2020155223A1 CN 2019075564 W CN2019075564 W CN 2019075564W WO 2020155223 A1 WO2020155223 A1 WO 2020155223A1
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WO
WIPO (PCT)
Prior art keywords
electrode assembly
tab
tabs
electrode
secondary battery
Prior art date
Application number
PCT/CN2019/075564
Other languages
English (en)
French (fr)
Inventor
雷育永
邢承友
王鹏
Original Assignee
宁德时代新能源科技股份有限公司
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 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to EP19913715.9A priority Critical patent/EP3905404B1/en
Publication of WO2020155223A1 publication Critical patent/WO2020155223A1/zh
Priority to US17/388,039 priority patent/US11695190B2/en

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Classifications

    • 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
    • H01M50/538—Connection of several leads or tabs of wound or folded electrode stacks
    • 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
    • H01M50/54—Connection of several leads or tabs of plate-like electrode stacks, e.g. electrode pole straps or bridges
    • 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
    • H01M10/0431—Cells with wound or folded electrodes
    • 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 of a single cell or a single battery
    • H01M50/147—Lids or covers
    • 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 of a single cell or a single battery
    • H01M50/147—Lids or covers
    • H01M50/148—Lids or covers characterised by their shape
    • H01M50/15—Lids or covers characterised by their shape for prismatic 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
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • 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
    • H01M50/176—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells for prismatic 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
    • H01M50/528—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
    • H01M50/531—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
    • 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
    • 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
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to the field of batteries, in particular to a secondary battery.
  • a secondary battery usually includes a case, an electrode assembly housed in the case, and a top cover assembly fixed to the case.
  • the electrode assembly is electrically connected to the electrode terminals of the top cover assembly through tabs.
  • the secondary battery usually has a plurality of electrode assemblies inside.
  • the tabs of the multiple electrode assemblies need to be gathered together and then connected to the electrode terminals at the same time. However, there is a certain distance between the tabs of adjacent electrode assemblies.
  • the tabs of multiple electrode assemblies are folded together, there will be a misalignment between the tabs. In order to compensate for the misalignment, all the tabs are set at the same time. To connect to the electrode terminal, it is necessary to increase the length of the tab, resulting in a waste of material; at the same time, too long tabs are easily inserted into the electrode assembly, causing a risk of short circuit.
  • the purpose of the present invention is to provide a secondary battery, which can reduce the requirement for the length of the tab, save material, and reduce the risk of short circuit.
  • the present invention provides a secondary battery including a first electrode assembly, a second electrode assembly, a case, and a top cover assembly.
  • the first electrode assembly and the second electrode assembly are housed in the casing.
  • the top cover assembly includes a top cover plate and a first electrode terminal, the top cover plate is connected to the housing, and the first electrode terminal is arranged on the top cover plate.
  • the first electrode assembly includes a first body and a first tab extending from the first body, and the first tab is multiple and stacked.
  • the second electrode assembly includes a second body and a second tab extending from the second body, and the second tab is multiple and stacked.
  • Each second tab is bent in a direction close to the first tab and connected to the first tab, and one end of the second tab away from the second body is a second end.
  • Each of the first tabs includes a first connecting portion extending beyond the second end, and the first connecting portion is connected to the first electrode terminal.
  • Each first tab also includes a first extension part, the first extension part is connected between the first connecting part and the first body, and the second tab is welded to the first extension part.
  • Each second tab also includes a second extension portion and a second connection portion, the second extension portion is connected to the second body and extends in a direction close to the first extension portion, and the second connection portion is away from the second extension portion from the second extension portion.
  • One end of the main body extends and is welded to the first extension part.
  • the second connecting portions of the plurality of second tabs are welded to the first extension portions of the plurality of first tabs to form a first welding zone.
  • the secondary battery further includes an adapter sheet, which is connected to the first electrode terminal.
  • the first connecting portions of the plurality of first tabs are welded to the transition piece to form a second welding zone, and the area of the second welding zone is greater than or equal to the area of the first welding zone.
  • the plurality of first tabs are located on one side of the thickness center of the first electrode assembly.
  • the plurality of second tabs are located on one side of the thickness center of the second electrode assembly.
  • One of the first tab and the second tab is arranged close to the interface between the first electrode assembly and the second electrode assembly, and the other of the first tab and the second tab is away from the first electrode assembly and the second electrode assembly Interface settings.
  • the first tab is located on the side of the thickness center of the first electrode assembly away from the interface.
  • the secondary battery further includes a third electrode assembly and a fourth electrode assembly housed in a casing, and the first electrode assembly, the second electrode assembly, the third electrode assembly, and the fourth electrode assembly are arranged in sequence.
  • the third electrode assembly includes a third body and a third tab extending from the third body, and the third tab is multiple and stacked.
  • the fourth electrode assembly includes a fourth body and a fourth tab extending from the fourth body, and the fourth tab is multiple and stacked.
  • Each third tab is bent toward the fourth tab and connected to the fourth tab, and one end of the third tab away from the third body is the third end.
  • Each of the fourth tabs includes a fourth connecting portion beyond the third end, and the fourth connecting portion is connected to the first electrode terminal.
  • the secondary battery further includes a fifth electrode assembly, the fifth electrode assembly is housed in the casing, and the fifth electrode assembly is disposed on a side of the second electrode assembly away from the first electrode assembly.
  • the fifth electrode assembly includes a fifth body and a fifth tab extending from the fifth body. The fifth tab is bent in a direction close to the second tab and welded to the second tab.
  • the fifth electrode assembly of the fifth electrode assembly adjacent to the second electrode assembly is welded to the second electrode assembly. Except for the fifth electrode assembly adjacent to the second electrode assembly, the fifth electrode assembly of the remaining fifth electrode assembly is welded to the fifth electrode assembly of the adjacent fifth electrode assembly.
  • the beneficial effects of the present invention are as follows: Compared with the known technology, the present application does not need to connect the first tab and the second tab to the first electrode terminal at the same time, that is, there is no need to compensate the first tab and the second tab. Therefore, the present application can reduce the need for the length of the tab, save materials, avoid the tab being inserted into the first body or the second body, and reduce the risk of short circuit.
  • Fig. 1 is an exploded view of a secondary battery according to the present invention.
  • Fig. 2 is a schematic diagram of a first embodiment of a secondary battery according to the present invention.
  • Fig. 3 is an enlarged view of the block part of Fig. 2.
  • Fig. 4 is a schematic diagram of an electrode assembly of a secondary battery according to the present invention.
  • Fig. 5 is a sectional view taken along the line A-A of Fig. 4.
  • Fig. 6 is a schematic diagram of the connection between the first tab and the second tab.
  • Fig. 7 is a schematic diagram of an adapter sheet of a secondary battery according to the present invention.
  • FIG. 8 is a schematic diagram of a second embodiment of a secondary battery according to the present invention, in which the casing and the top cover assembly are omitted.
  • Figure 9 is an enlarged view of the block part of Figure 8.
  • Fig. 10 is a schematic diagram of a third embodiment of a secondary battery according to the present invention.
  • Figure 11 is an enlarged view of the block part of Figure 10;
  • Fig. 12 is a schematic diagram of a fourth embodiment of a secondary battery according to the present invention.
  • Fig. 13 is an enlarged view of the block part of Fig. 12.
  • the secondary battery of the present application includes an electrode assembly, a case 6 and a top cover assembly 7.
  • the housing 6 may be made of conductive metal materials such as aluminum or aluminum alloy.
  • the top cover assembly 7 includes a top cover plate 71, a first electrode terminal 72 and a second electrode terminal 73.
  • the top cover plate 71 is connected to the housing 6 and covers the opening of the housing 6 so as to enclose the electrode assembly in the housing 6.
  • the first electrode terminal 72 and the second electrode terminal 73 are provided on the top cover 71.
  • the top cover 71 is formed with two through terminal holes, and the first electrode terminal 72 and the second electrode terminal 73 are located outside the top cover 71 and respectively cover the two terminal holes. In the present application, the first electrode terminal 72 and the second electrode terminal 73 do not occupy the internal space of the housing 6.
  • each electrode assembly is plural and arranged along the thickness direction Y. 4, each electrode assembly includes a positive pole piece P1, a negative pole piece P2, and a separator P3, and the separator P3 separates the positive pole piece P1 and the negative pole piece P2.
  • the positive pole piece P1, the negative pole piece P2 and the separator P3 are wound into a flat structure.
  • the positive pole piece P1 includes a positive current collector P11 and a positive active material layer P12, and the positive active material layer P12 is coated on a partial area of the positive current collector P11.
  • the positive electrode current collector P11 may be aluminum foil, and the positive electrode active material layer P12 includes a ternary material, lithium manganate or lithium iron phosphate.
  • the area of the positive electrode active material layer P12 and the positive electrode current collector P11 coated with the positive electrode active material layer P12 forms the positive electrode coating area of the positive electrode piece P1, and the area of the positive electrode current collector P11 not coated with the positive electrode active material layer P12 forms the positive electrode.
  • the negative pole piece P2 includes a negative current collector P21 and a negative active material layer P22, and the negative active material layer P22 is coated on a partial area of the negative current collector P21.
  • the anode current collector P21 may be copper foil, and the anode active material layer P22 includes graphite or silicon.
  • the area of the negative electrode active material layer P22 and the negative electrode current collector P21 coated with the negative electrode active material layer P22 forms the negative electrode coating area of the negative electrode piece P2, and the area of the negative electrode current collector P21 not coated with the negative electrode active material layer P22 forms the negative electrode.
  • the plurality of electrode assemblies includes a first electrode assembly 1 and a second electrode assembly 2.
  • the first electrode assembly 1 includes a first body 11 and a first tab 12 extending from the first body 11.
  • the first tabs 12 are multiple and stacked.
  • the first body 11 includes the positive electrode coating area, the separator P3, and the negative electrode coating area of the first electrode assembly 1.
  • the first tab 12 is the blank area of the negative electrode of the first electrode assembly 1; in an alternative embodiment, the first tab 12 may also be the blank area of the positive electrode of the first electrode assembly 1.
  • the second electrode assembly 2 includes a second main body 21 and second tabs 22 extending from the second main body 21.
  • the second tabs 22 are multiple and stacked.
  • the second body 21 includes the positive electrode coating area, the separator P3, and the negative electrode coating area of the second electrode assembly 2.
  • the second tab 22 and the first tab 12 have the same polarity.
  • the second tab 22 is the negative electrode blank area of the second electrode assembly 2.
  • the first electrode assembly 1 and the second electrode assembly 2 are generally electrode assemblies of the same specifications, and the length of the first tab 12 is substantially equal to the length of the second tab 22.
  • Each second tab 22 is bent toward the first tab 12 and connected to the first tab 12, and one end of each second tab 22 away from the second body 21 is a second end 224.
  • Each first tab 12 extends from the first body 11, and one end of the first tab 12 away from the first body 11 is a first end 124.
  • the first end 124 of the first tab 12 extends beyond the second end 224 of the second tab 22.
  • each first tab 12 includes a first connecting portion 122 that extends beyond the second end 224 (that is, the first connecting portion 122 is a portion of the first tab 12 that extends beyond the second end 224), and each first pole
  • the first connecting portion 122 of the ear 12 extends beyond the second end 224 of all the second tabs 22.
  • the first connection portion 122 is connected to the first electrode terminal 72.
  • This application first connects the second tab 22 and the first tab 12 together, and then connects the first connecting portion 122 of the first tab 12 beyond the second tab 22 to the first electrode terminal 72.
  • the present application does not need to connect the first tab 12 and the second tab 22 to the first electrode terminal 72 at the same time, that is, there is no need to compensate the gap between the first tab 12 and the second tab 22. Therefore, the present application can reduce the need for the length of the tabs, save materials, avoid the tabs being inserted into the first body 11 or the second body 21, and reduce the risk of short circuit.
  • the secondary battery of the present application further includes an adapter sheet 8 which connects the first electrode terminal 72 and the first connecting portion 122.
  • the adapter piece 8 can be formed by punching to form a protrusion, and the protrusion extends to the terminal hole and is welded to the first electrode terminal 72.
  • the protrusion forms a recess on the side facing the electrode assembly.
  • the second tab 22 can be connected to the first tab 12 by ultrasonic welding, and then the first connecting portion 122 of the first tab 12 can be welded to the adapter plate 8 by ultrasonic welding. , And finally the adapter sheet 8 is welded to the first electrode terminal 72.
  • the present application can reduce the length of the first tab 12 so as to prevent the first tab 12 from covering the protrusion of the adapter sheet 8 and ensure the welding strength.
  • Each first tab 12 further includes a first extension part 121 connected between the first connection part 122 and the first body 11.
  • the first extension portion 121 extends from an end of the first connection portion 122 away from the first end portion 124, and the first extension portion 121 is bent toward the first body 11 relative to the first connection portion 122.
  • the second tab 22 is preferably welded to the first extension part 121.
  • the current of the second electrode assembly 2 can be transmitted to the adapter sheet 8 via the first extension portion 121 and the first connection portion 122. Therefore, the second tab 22 does not need to communicate with the adapter sheet 8 anymore. Welding, thereby reducing the length requirement of the second tab 22.
  • each first tab 12 further includes a first condensed portion 123, which extends from the first main body 11 and is connected to the first extension portion 121; by bending the first condensed portion 123, a plurality of One pole 12 is gathered together. Compared with the distance between the first tab 12 and the second tab 22, the distance between adjacent first tabs 12 is very small. Therefore, when a plurality of first tabs 12 are folded together, the more The misalignment between the first ends 124 of the first tab 12 is small, and the welding effect on the first tab 12 and the adapter piece 8 is low.
  • Each second tab 22 further includes a second extension part 221, a second connection part 222 and a second gathering part 223.
  • the second condensed portion 223 extends from the second main body 21, and the second extension 221 is connected to an end of the second condensed portion 223 away from the second main body 21 and extends toward the first extension 121.
  • the second connecting portion 222 extends from An end of the second extension portion 221 away from the second gathering portion 223 extends.
  • the extension length of the second extension portion 221 is substantially equal to the distance between the second condensed portion 223 and the first extension portion 121.
  • the second connection portion 222 and the first extension portion 121 are stacked and welded together.
  • the second connecting portion 222 is bent relative to the second extending portion 221.
  • the second connecting portions 222 of the plurality of second tabs 22 are welded to the first extension portions 121 of the plurality of first tabs 12 to form the first welding area W1.
  • the current of the second electrode assembly 2 can be transmitted to the first tab 12 via the first welding zone W1.
  • the area of the first welding zone W1 determines the flow capacity between the first tab 12 and the second tab 22.
  • the first connecting portions 122 of the plurality of first tabs 12 are welded to the adapter sheet 8 to form a second welding area W2.
  • the currents of the first electrode assembly 1 and the second electrode assembly 2 are collected to the first connection portion 122 and are transmitted to the first electrode terminal 72 via the second welding area W2 and the transition piece 8.
  • the area of the second welding zone W2 determines the flow capacity between the first connecting portion 122 and the adapter sheet 8. Since the first tab 12 is relatively thin, it is easy to be damaged during direct welding. Therefore, referring to FIG.
  • the present application further includes a welding protection sheet 9, and the first connecting portions 122 of the plurality of first tabs 12 are located at the welding protection sheet 9 and Between the transfer sheets 8, the welding protection sheet 9, the first connecting portion 122 and the transfer sheet 8 are welded together to form a second welding area W2.
  • the current on the second welding zone W2 will be greater than the current on the first welding zone W1, so the area of the second welding zone W2 is preferably larger than the area of the first welding zone W1 to improve the overall overcurrent capability.
  • the area of the first welding zone W1 can also be appropriately increased; that is, the area of the second welding zone W2 can also be equal to the first welding zone. The area of area W1.
  • the plurality of first tabs 12 are located on one side of the thickness center of the first electrode assembly 1 (ie, the center along the thickness direction Y).
  • the first electrode assembly 1 of the present application has a winding structure, and the center of the thickness of the first electrode assembly 1 is the winding center of the first electrode assembly 1.
  • the plurality of second tabs 22 are located on one side of the thickness center of the second electrode assembly 2 (ie, the center along the thickness direction Y).
  • first tab 12 and the second tab 22 is located close to the interface of the first electrode assembly 1 and the second electrode assembly 2, and the other of the first tab 12 and the second tab 22 is far from the first electrode
  • the interface between the assembly 1 and the second electrode assembly 2 is set.
  • the arrangement of the first tab 12 of the first electrode assembly 1 is the same as the arrangement of the second tab 22 of the second electrode assembly 2, that is, the arrangement of the first electrode assembly 1 and the second electrode assembly 2
  • the specifications are the same, the error can be reduced during assembly, which plays a role of foolproof.
  • this can increase the distance between the first extension portion 121 and the second gathering portion 223; correspondingly, the extension length of the second extension portion 221 is increased, while the extension length of the second connection portion 222 is decreased.
  • the length of the first connecting portion 122 can be correspondingly increased.
  • the length of the first connecting portion 122 is increased, sufficient space can be provided for the welding of the first tab 12 and the adapter piece 8 to avoid interference of the second end 224 of the second tab 22 and ensure the welding strength.
  • the first tab 12 is located on the side of the thickness center of the first electrode assembly 1 away from the interface.
  • the secondary battery of the present application may further include a third electrode assembly 3 and a fourth electrode assembly 4 housed in the casing 6, the first electrode assembly 1, the second electrode assembly 2, and the third electrode assembly 4.
  • the electrode assembly 3 and the fourth electrode assembly 4 are arranged in sequence.
  • the third electrode assembly 3 includes a third body 31 and third tabs 32 extending from the third body 31, and the third tabs 32 are multiple and stacked.
  • the third body 31 includes the positive electrode coating area of the third electrode assembly 3, the separator P3, and the negative electrode coating area.
  • the third tab 32 and the first tab 12 have the same polarity.
  • the third tab 32 is the negative blank area of the third electrode assembly 3.
  • the fourth electrode assembly 4 includes a fourth main body 41 and fourth tabs 42 extending from the fourth main body 41.
  • the fourth tabs 42 are multiple and stacked.
  • the fourth body 41 includes the positive electrode coating area of the fourth electrode assembly 4, the separator P3, and the negative electrode coating area.
  • the fourth tab 42 and the first tab 12 have the same polarity.
  • the fourth tab 42 is the negative blank area of the fourth electrode assembly 4.
  • each third tab 32 is bent toward the fourth tab 42 and connected to the fourth tab 42, and the end of each third tab 32 away from the third body 31 is the third end 321 .
  • each fourth pole 42 extends from the fourth body 41 and extends along the extending direction of the fourth tab 42, and the fourth tab 42 extends beyond the third end 321 of the third tab 32.
  • each fourth pole 42 includes a fourth connecting portion 422 that exceeds the third end 321 (that is, the fourth connecting portion 422 is a portion of the fourth pole 42 that exceeds the third end 321); each fourth pole The fourth connecting portion 422 of the ear 42 extends beyond the third end 321 of all third tabs 32.
  • the fourth connection portion 422 is connected to the first electrode terminal 72.
  • the adapter piece 8 includes a first part 81, a second part 82, and a third part 83.
  • the first part 81 is welded to the first connecting part 122
  • the second part 82 is welded to the fourth connecting part 422
  • the third part 83 Connected between the first part 81 and the second part 82.
  • a protrusion is formed on the third portion 83 by pressing, and the protrusion is welded to the first electrode terminal 72.
  • This application first connects the third tab 32 and the fourth tab 42 together, and then connects the fourth connecting portion 422 of the fourth tab 42 that extends beyond the third tab 32 to the first electrode terminal 72.
  • the present application does not need to connect the third tab 32 and the fourth tab 42 to the first electrode terminal 72 at the same time, that is, there is no need to compensate for the gap between the third tab 32 and the fourth tab 42. Therefore, the present application can reduce the need for the length of the tab, save materials, avoid the tab from being inserted into the third body 31 or the fourth body 41, and reduce the risk of short circuit.
  • each fourth tab 42 further includes a fourth extension portion 421, and the fourth extension portion 421 is connected between the fourth connection portion 422 and the fourth body 41.
  • the fourth extension portion 421 is bent toward the fourth body 41 relative to the fourth connecting portion 422.
  • a plurality of third tabs 32 are located on one side of the thickness center of the third electrode assembly 3 (ie, the center along the thickness direction Y), and a plurality of fourth tabs 42 are located at the thickness center of the fourth electrode assembly 4 ( That is, one side along the center of the thickness direction Y).
  • the plurality of first tabs 12 are located on the side of the thickness center of the first electrode assembly 1 away from the second electrode assembly 2, and the plurality of second tabs 22 are located at the thickness center of the second electrode assembly 2 close to the first One side of the electrode assembly 1.
  • a plurality of fourth tabs 42 are located on the side of the thickness center of the fourth electrode assembly 4 away from the third electrode assembly 3, and a plurality of third tabs 32 are located at the thickness center of the third electrode assembly 2 near the fourth electrode.
  • One side of component 4. In this way, the distance between the fourth tab 42 and the first tab 12 can be increased, thereby increasing the extension length of the third portion 83 of the adapter plate 8 and providing a sufficient area for the stamping protrusion.
  • the third part 83 of the transfer piece 8 has a relatively large length, which is convenient for opening a fuse hole on the third part 83.
  • the secondary battery of the second embodiment further includes a fifth electrode assembly 5 housed in the casing 6.
  • the fifth electrode assembly 5 is disposed on the second electrode assembly 2 away from the first electrode assembly 1. Side.
  • the fifth electrode assembly 5 includes a fifth main body 51 and a fifth tab 52 extending from the fifth main body 51, and the fifth tab 52 is multiple and stacked.
  • the fifth body 51 includes the positive electrode coating area of the fifth electrode assembly 5, the separator P3, and the negative electrode coating area.
  • the fifth tab 52 has the same polarity as the first tab 12. In this embodiment, the fifth tab 52 is the negative blank area of the fifth electrode assembly 5.
  • the fifth tab 52 is bent toward the second tab 22 and welded to the second tab 22. Specifically, the fifth tab 52 may be fixed to the second extension portion 221 by ultrasonic welding to form the third welding area W3.
  • the tabs of the three electrode assemblies are gathered together and welded to the adapter sheet 8 at the same time, the tabs of the three electrode assemblies will be seriously misaligned; compared to the two electrode assemblies, the three The tabs of each electrode assembly require a greater length.
  • the fifth lug 52 only needs to be welded to the second extension 221, and does not need to be welded to the first lug 12 or the adapter sheet 8. Therefore, the present application can effectively reduce the length of the lug. Claim.
  • the current in the first welding zone W1 will be greater than the current in the third welding zone W3; to meet the overcurrent requirements and strength requirements, the area of the first welding zone W1 is preferably equal to or greater than the area of the third welding zone W3.
  • the third embodiment omits the third electrode assembly 3 and the fourth electrode assembly 4. That is, the secondary battery of the third embodiment only includes the first electrode assembly 1, the second electrode assembly 2, and the fifth electrode assembly 5.
  • the fifth electrode assemblies 5 of the third embodiment there are a plurality of fifth electrode assemblies 5 of the third embodiment, and they are arranged in sequence along a direction away from the second electrode assembly 2, and the fifth electrode assembly 5 of each fifth electrode assembly 5 faces toward the second electrode assembly 22. The direction bends.
  • the fifth tab 52 of the fifth electrode assembly 5 adjacent to the second electrode assembly 2 is welded to the second tab 22. Except for the fifth electrode assembly 5 adjacent to the second electrode assembly 2, the fifth tab 52 of each fifth electrode assembly 5 is welded to the fifth tab 52 of the adjacent fifth electrode assembly 5.
  • the adapter piece 8 only needs to be welded to the first connecting portion 122. Therefore, the structure of the adapter piece 8 can be simplified (for example, the second part 82 is removed), thereby reducing the adapter piece 8 The space occupied.
  • FIGS. 12 and 13 are schematic diagrams of a fourth embodiment of the secondary battery of the application. Compared with the first embodiment, the positions of the tabs of the fourth embodiment are different.
  • the plurality of first tabs 12 are located at the side of the thickness center of the first electrode assembly 1 close to the second electrode assembly 2, and the plurality of second tabs 22 are located at the thickness center of the second electrode assembly 2 far away from the first electrode assembly 2.
  • a plurality of fourth tabs 42 are located at the side of the thickness center of the fourth electrode assembly 4 close to the third electrode assembly 3, and a plurality of third tabs 32 are located at the thickness center of the third electrode assembly 2 away from the fourth electrode.
  • the fourth embodiment can reduce the distance between the fourth tab 42 and the first tab 12, reduce the extension length of the third portion 83 of the adapter plate 8, and save materials.

Abstract

本发明提供了一种二次电池，其包括第一电极组件、第二电极组件、壳体以及顶盖组件。第一电极组件和第二电极组件收容于壳体内。顶盖组件包括顶盖板和第一电极端子，顶盖板连接于壳体，第一电极端子设置于顶盖板。第一电极组件包括第一主体和从第一主体延伸的第一极耳，第一极耳为多个且层叠设置。第二电极组件包括第二主体和从第二主体延伸的第二极耳，第二极耳为多个且层叠设置。各第二极耳朝靠近第一极耳的方向弯折并连接于第一极耳，且第二极耳远离第二主体的一端为第二端部。各第一极耳包括超出第二端部的第一连接部，且第一连接部连接于第一电极端子。

Description

二次电池 技术领域
本发明涉及电池领域，尤其涉及一种二次电池。
背景技术
二次电池通常包括壳体、收容于壳体的电极组件和固定于壳体的顶盖组件，电极组件通过极耳与顶盖组件的电极端子电连接。为了提高容量，二次电池通常在内部设置多个电极组件。在装配时，所述多个电极组件的极耳需要先收拢在一起，然后再同时连接到电极端子。然而，相邻的电极组件的极耳之间存在一定的间距，当多个电极组件的极耳收拢在一起时，极耳之间会出现错位；而为了补偿错位，并将所有的极耳同时连接到电极端子，就需要增大极耳的长度，导致材料的浪费；同时，过长的极耳容易插入到电极组件内部，引发短路风险。
发明内容
鉴于背景技术中存在的问题，本发明的目的在于提供一种二次电池，其能降低对极耳的长度的需求，节省材料，降低短路风险。
为了实现上述目的，本发明提供了一种二次电池，其包括第一电极组件、第二电极组件、壳体以及顶盖组件。第一电极组件和第二电极组件收容于壳体内。顶盖组件包括顶盖板和第一电极端子，顶盖板连接于壳体，第一电极端子设置于顶盖板。第一电极组件包括第一主体和从第一主体延伸的第一极耳，第一极耳为多个且层叠设置。第二电极组件包括第二主体和从第二主体延伸的第二极耳，第二极耳为多个且层叠设置。各第二极耳朝靠近第一极耳的方向弯折并连接于第一极耳，且第二极耳远离第二主体的一端为第二端部。各第一极耳包括超出第二端部的第一连接部，且第一连接部连接于第一电极端子。
各第一极耳还包括第一延伸部，第一延伸部连接于第一连接部与第一主 体之间，第二极耳焊接于第一延伸部。
各第二极耳还包括第二延伸部和第二连接部，第二延伸部连接于第二主体并朝靠近第一延伸部的方向延伸，第二连接部从第二延伸部的远离第二主体的一端延伸并焊接于第一延伸部。
多个第二极耳的第二连接部焊接于多个第一极耳的第一延伸部并形成第一熔接区。
二次电池还包括转接片，转接片连接于第一电极端子。多个第一极耳的第一连接部焊接于转接片并形成第二熔接区，且第二熔接区的面积大于或等于第一熔接区的面积。
多个第一极耳位于第一电极组件的厚度中心的一侧。多个第二极耳位于第二电极组件的厚度中心的一侧。第一极耳和第二极耳中的一个靠近第一电极组件和第二电极组件的交界面设置，第一极耳和第二极耳中的另一个远离第一电极组件和第二电极组件的交界面设置。
第一极耳位于第一电极组件的厚度中心的远离所述交界面的一侧。
所述二次电池还包括收容于壳体内的第三电极组件和第四电极组件，第一电极组件、第二电极组件、第三电极组件和第四电极组件依次排列。第三电极组件包括第三主体和从第三主体延伸的第三极耳，第三极耳为多个且层叠设置。第四电极组件包括第四主体和从第四主体延伸的第四极耳，第四极耳为多个且层叠设置。各第三极耳朝靠近第四极耳的方向弯折并连接于第四极耳，且第三极耳远离第三主体的一端为第三端部。各第四极耳包括超出第三端部的第四连接部，且第四连接部连接于第一电极端子。
所述二次电池还包括第五电极组件，第五电极组件收容于壳体内，且第五电极组件设置于第二电极组件的远离第一电极组件的一侧。第五电极组件包括第五主体和从第五主体延伸的第五极耳，第五极耳朝靠近第二极耳的方向弯折并焊接于第二极耳。
第五电极组件为多个并沿远离第二电极组件的方向依次设置，且各第五电极组件的第五极耳朝靠近第二极耳的方向弯折。与第二电极组件相邻的第五电极组件的第五极耳焊接于第二极耳。除与第二电极组件相邻的第五电极组件外，其余的各第五电极组件的第五极耳焊接于相邻的第五电极组件的第五极耳。
本发明的有益效果如下：与已知技术相比，本申请无需同时将第一极耳和第二极耳连接到第一电极端子，也就是说，无需补偿第一极耳和第二极耳之间的错位；因此，本申请可以减小对极耳长度的需求，节省材料，避免极耳插入第一主体或第二主体，降低短路风险。
附图说明
图1为根据本发明的二次电池的分解图。
图2为根据本发明的二次电池的第一实施例的示意图。
图3为图2的方框部分的放大图。
图4为根据本发明的二次电池的电极组件的示意图。
图5为图4沿线A-A作出的断面图。
图6为第一极耳与第二极耳的连接示意图。
图7为根据本发明的二次电池的转接片的示意图。
图8为根据本发明的二次电池的第二实施例的示意图，其中壳体和顶盖组件省略。
图9为图8的方框部分的放大图；
图10为根据本发明的二次电池的第三实施例的示意图。
图11为图10的方框部分的放大图；
图12为根据本发明的二次电池的第四实施例的示意图。
图13为图12的方框部分的放大图。
其中，附图标记说明如下：
1第一电极组件               52第五极耳
11第一主体                  6壳体
12第一极耳                  7顶盖组件
121第一延伸部               71顶盖板
122第一连接部               72第一电极端子
123第一收拢部               73第二电极端子
124第一端部                 8转接片
2第二电极组件               81第一部分
21第二主体                  82第二部分
22第二极耳                  83第三部分
221第二延伸部               9焊接保护片
222第二连接部               P1正极极片
223第二收拢部               P11正极集流体
224第二端部                 P12正极活性物质层
3第三电极组件               P2负极极片
31第三主体                  P21负极集流体
32第三极耳                  P22负极活性物质层
321第三端部                 P3隔膜
4第四电极组件               W1第一熔接区
41第四主体                  W2第二熔接区
42第四极耳                  W3第三熔接区
421第四延伸部               X宽度方向
422第四连接部               Y厚度方向
5第五电极组件               Z高度方向
51第五主体
具体实施方式
为了使本申请的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本申请，并不用于限定本申请。
在本申请的描述中，除非另有明确的规定和限定，术语“第一”、“第二”、“第三”仅用于描述的目的，而不能理解为指示或暗示相对重要性；术语“多个”是指两个以上(包括两个)；除非另有规定或说明，术语“连接”应做广义理解，例如，“连接”可以是固定连接，也可以是可拆卸连接，或一体地连接，或电连接，或信号连接；“连接”可以是直接相连，也可以通过中间媒介间接相连。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
本说明书的描述中，需要理解的是，本申请实施例所描述的“上”、“下”等方位词是以附图所示的角度来进行描述的，不应理解为对本申请实施例的 限定。下面通过具体的实施例并结合附图对本申请做进一步的详细描述。
在第一实施例中，参照图1，本申请的二次电池包括电极组件、壳体6以及顶盖组件7。
壳体6内部形成有容纳腔，以收容电极组件和电解液。壳体6一端形成有开口，而电极组件可经由所述开口放置到壳体6内。壳体6可由铝或铝合金等导电金属的材料制成。
顶盖组件7包括顶盖板71、第一电极端子72和第二电极端子73，顶盖板71连接于壳体6且覆盖壳体6的开口，从而将电极组件封闭在壳体6内。第一电极端子72和第二电极端子73设置于顶盖板71。顶盖板71形成有两个贯通的端子孔，第一电极端子72和第二电极端子73位于顶盖板71的外侧并分别覆盖两个端子孔。在本申请中，第一电极端子72和第二电极端子73不占用壳体6的内部空间。
电极组件为多个并沿厚度方向Y布置。参照图4，各电极组件包括正极极片P1、负极极片P2和隔膜P3，隔膜P3将正极极片P1和负极极片P2隔开。优选地，正极极片P1、负极极片P2和隔膜P3卷绕为扁平状结构。
参照图5，正极极片P1包括正极集流体P11和正极活性物质层P12，正极活性物质层P12涂覆于正极集流体P11的部分区域。正极集流体P11可为铝箔，正极活性物质层P12包括三元材料、锰酸锂或磷酸铁锂。正极活性物质层P12和正极集流体P11的涂覆有正极活性物质层P12的区域形成正极极片P1的正极涂覆区，正极集流体P11的未涂覆正极活性物质层P12的区域形成正极极片P1的正极空白区。当正极极片P1卷绕成型后，多个正极空白区层叠设置。
负极极片P2包括负极集流体P21和负极活性物质层P22，负极活性物质层P22涂覆于负极集流体P21的部分区域。负极集流体P21可为铜箔，负极活性物质层P22包括石墨或硅。负极活性物质层P22和负极集流体P21的涂覆有负极活性物质层P22的区域形成负极极片P2的负极涂覆区，负极集流体P21的未涂覆负极活性物质层P22的区域形成负极极片P2的负极空白区。当负极极片P2卷绕成型后，多个负极空白区层叠设置。
所述多个电极组件包括第一电极组件1和第二电极组件2。
参照图3和图6，第一电极组件1包括第一主体11和从第一主体11延 伸的第一极耳12，第一极耳12为多个且层叠设置。具体地，第一主体11包括第一电极组件1的正极涂覆区、隔膜P3和负极涂覆区。在本实施例中，第一极耳12为第一电极组件1的负极空白区；在替代地实施例中，第一极耳12也可为第一电极组件1的正极空白区。
第二电极组件2包括第二主体21和从第二主体21延伸的第二极耳22，第二极耳22为多个且层叠设置。具体地，第二主体21包括第二电极组件2的正极涂覆区、隔膜P3和负极涂覆区。第二极耳22与第一极耳12的极性相同，在本实施例中，第二极耳22为第二电极组件2的负极空白区。
在二次电池中，为了便于生产和装配，第一电极组件1和第二电极组件2一般为同等规格的电极组件，第一极耳12的长度大体等于第二极耳22的长度。
各第二极耳22朝靠近第一极耳12的方向弯折并连接于第一极耳12，且各第二极耳22远离第二主体21的一端为第二端部224。
各第一极耳12从第一主体11延伸，且第一极耳12远离第一主体11的一端为第一端部124。沿第一极耳12的延伸方向，第一极耳12的第一端部124超出第二极耳22的第二端部224。具体地，各第一极耳12包括超出第二端部224的第一连接部122(即第一连接部122为第一极耳12的超出第二端部224的部分)，各第一极耳12的第一连接部122超出所有的第二极耳22的第二端部224。在本申请中，第一连接部122连接于第一电极端子72。
本申请先将第二极耳22和第一极耳12连接在一起，然后再将第一极耳12的超出第二极耳22的第一连接部122连接到第一电极端子72。与已知技术相比，本申请无需同时将第一极耳12和第二极耳22连接到第一电极端子72，也就是说，无需补偿第一极耳12和第二极耳22之间的错位；因此，本申请可以减小对极耳长度的需求，节省材料，避免极耳插入第一主体11或第二主体21，降低短路风险。
优选地，本申请的二次电池还包括转接片8，转接片8连接第一电极端子72和第一连接部122。转接片8可通过冲压形成突部，突部延伸到端子孔并焊接于第一电极端子72。突部在朝向电极组件的一侧形成凹部。
在装配时，可先通过超声波焊接等方式将第二极耳22连接到第一极耳12，然后通过超声波焊接等方式将第一极耳12的第一连接部122焊接到转 接片8上，最后再将转接片8焊接到第一电极端子72上。
如果第一极耳12过长，第一极耳12很容易延伸到转接片8的突部的下侧并遮挡突部，影响突部与第一电极端子72的焊接。与已知技术相比，本申请可以减小第一极耳12的长度，从而避免第一极耳12遮挡转接片8的突部，保证焊接强度。
各第一极耳12还包括第一延伸部121，第一延伸部121连接于第一连接部122与第一主体11之间。优选地，第一延伸部121从第一连接部122的远离第一端部124的一端延伸，且第一延伸部121相对于第一连接部122朝靠近第一主体11的方向弯折。通过弯折第一极耳12，可以减小第一极耳12在二次电池的高度方向Z上占用的空间，提高能量密度。
第二极耳22优选焊接于第一延伸部121。在二次电池的工作过程中，第二电极组件2的电流可经由第一延伸部121和第一连接部122传输到转接片8，因此，第二极耳22无需再与转接片8焊接，从而降低第二极耳22对长度的需求。
参照图6，各第一极耳12还包括第一收拢部123，第一收拢部123从第一主体11延伸且连接于第一延伸部121；通过弯折第一收拢部123，多个第一极耳12收拢在一起。与第一极耳12和第二极耳22的间距相比，相邻的第一极耳12之间的间距很小，因此，当多个第一极耳12收拢在一起时，所述多个第一极耳12的第一端部124之间的错位较小，对第一极耳12和转接片8的焊接影响较低。
各第二极耳22还包括第二延伸部221、第二连接部222和第二收拢部223。第二收拢部223从第二主体21延伸，第二延伸部221连接于第二收拢部223的远离第二主体21的一端并朝靠近第一延伸部121的方向延伸，第二连接部222从第二延伸部221的远离第二收拢部223的一端延伸。
通过弯折第二收拢部223，多个第二极耳22收拢在一起。第二延伸部221的延伸长度大体等于第二收拢部223和第一延伸部121的间距。第二连接部222与第一延伸部121层叠设置并焊接在一起。第二连接部222相对于第二延伸部221弯折。
在本实施例中，多个第二极耳22的第二连接部222焊接于多个第一极耳12的第一延伸部121并形成第一熔接区W1。在使用过程中，第二电极组 件2的电流可经由第一熔接区W1传输到第一极耳12。第一熔接区W1的面积决定第一极耳12和第二极耳22之间的过流能力。
多个第一极耳12的第一连接部122焊接于转接片8并形成第二熔接区W2。第一电极组件1和第二电极组件2的电流汇集到第一连接部122，并经由第二熔接区W2和转接片8传输到第一电极端子72。第二熔接区W2的面积决定第一连接部122与转接片8之间的过流能力。由于第一极耳12较薄，直接焊接时容易被破坏，因此，参照图2，本申请还包括焊接保护片9，多个第一极耳12的第一连接部122位于焊接保护片9和转接片8之间，且焊接保护片9、第一连接部122及转接片8焊接在一起并形成第二熔接区W2。
在使用过程中，第二熔接区W2上的电流会大于第一熔接区W1上的电流，所以第二熔接区W2的面积优选大于第一熔接区W1的面积，以改善整体的过流能力。当然，为了提高第一极耳12和第二极耳22的连接强度，也可以适当地增大第一熔接区W1的面积；也就是说，第二熔接区W2的面积也可以等于第一熔接区W1的面积。
参照图3，多个第一极耳12位于第一电极组件1的厚度中心(即沿厚度方向Y的中心)的一侧。参照图4，本申请的第一电极组件1为卷绕结构，第一电极组件1的厚度中心为第一电极组件1的卷绕中心。同样地，多个第二极耳22位于第二电极组件2的厚度中心(即沿厚度方向Y的中心)的一侧。
第一极耳12和第二极耳22中的一个靠近第一电极组件1和第二电极组件2的交界面设置，第一极耳12和第二极耳22中的另一个远离第一电极组件1和第二电极组件2的交界面设置。此时，第一电极组件1的第一极耳12的布置方式与第二电极组件2的第二极耳22的布置方式相同，也就是说，第一电极组件1和第二电极组件2的规格相同，装配时可以降低误差，起到防呆的作用。另外，这样可以增大第一延伸部121和第二收拢部223的间距；对应地，第二延伸部221的延伸的长度增大，而第二连接部222延伸的长度减小。第二连接部222减小时，可以对应地增大第一连接部122的长度。第一连接部122的长度增大时，可以为第一极耳12和转接片8的焊接提供足够的空间，避免第二极耳22的第二端部224干涉，保证焊接强度。
优选地，第一极耳12位于第一电极组件1的厚度中心的远离所述交界 面的一侧。
为了提高二次电池的容量，本申请的二次电池还可包括收容于壳体6内的第三电极组件3和第四电极组件4，第一电极组件1、第二电极组件2、第三电极组件3和第四电极组件4依次排列。
第三电极组件3包括第三主体31和从第三主体31延伸的第三极耳32，第三极耳32为多个且层叠设置。具体地，第三主体31包括第三电极组件3的正极涂覆区、隔膜P3和负极涂覆区。第三极耳32与第一极耳12的极性相同，在本实施例中，第三极耳32为第三电极组件3的负极空白区。
第四电极组件4包括第四主体41和从第四主体41延伸的第四极耳42，第四极耳42为多个且层叠设置。具体地，第四主体41包括第四电极组件4的正极涂覆区、隔膜P3和负极涂覆区。第四极耳42与第一极耳12的极性相同，在本实施例中，第四极耳42为第四电极组件4的负极空白区。
参照图3，各第三极耳32朝靠近第四极耳42的方向弯折并连接于第四极耳42，且各第三极耳32远离第三主体31的一端为第三端部321。
第四极耳42从第四主体41延伸，且沿第四极耳42的延伸方向，第四极耳42超出第三极耳32的第三端部321。具体地，各第四极耳42包括超出第三端部321的第四连接部422(即第四连接部422为第四极耳42的超出第三端部321的部分)；各第四极耳42的第四连接部422超出所有第三极耳32的第三端部321。在本申请中，第四连接部422连接于第一电极端子72。
参照图7，转接片8包括第一部分81、第二部分82和第三部分83，第一部分81焊接于第一连接部122，第二部分82焊接于第四连接部422，第三部分83连接于第一部分81和第二部分82之间。通过冲压在第三部分83上形成突部，突部焊接于第一电极端子72。
本申请先将第三极耳32和第四极耳42连接在一起，然后再将第四极耳42的超出第三极耳32的第四连接部422连接到第一电极端子72。与已知技术相比，本申请无需同时将第三极耳32和第四极耳42连接到第一电极端子72，也就是说，无需补偿第三极耳32和第四极耳42之间的错位；因此，本申请可以减小对极耳长度的需求，节省材料，避免极耳插入第三主体31或第四主体41，降低短路风险。
参照图3，各第四极耳42还包括第四延伸部421，第四延伸部421连接 于第四连接部422与第四主体41之间。优选地，第四延伸部421相对于第四连接部422朝靠近第四主体41的方向弯折。通过弯折第四极耳42，可以减小第四极耳42在二次电池的高度方向Z上占用的空间，提高能量密度。
参照图3，多个第三极耳32位于第三电极组件3的厚度中心(即沿厚度方向Y的中心)的一侧，多个第四极耳42位于第四电极组件4的厚度中心(即沿厚度方向Y的中心)的一侧。
优选地，多个第一极耳12位于第一电极组件1的厚度中心的远离第二电极组件2的一侧，多个第二极耳22位于第二电极组件2的厚度中心的靠近第一电极组件1的一侧。同时，多个第四极耳42位于第四电极组件4的厚度中心的远离第三电极组件3的一侧，多个第三极耳32位于第三电极组件2的厚度中心的靠近第四电极组件4的一侧。这样可以增大第四极耳42和第一极耳12的间距，从而提高转接片8的第三部分83的延伸长度，为冲压突部提供足够的面积。同时，转接片8的第三部分83具有较大的长度，便于在第三部分83上开设熔断孔。
下面对本申请的二次电池的其它实施例进行说明。为了简化描述，以下仅主要介绍其它实施例与第一实施例的不同之处，未描述的部分可以参照第一实施例进行理解。
图8和图9为本申请的二次电池的第二实施例的示意图。与第一实施例相比，第二实施例的二次电池还包括收容于壳体6内的第五电极组件5，第五电极组件5设置于第二电极组件2的远离第一电极组件1的一侧。
第五电极组件5包括第五主体51和从第五主体51延伸的第五极耳52，第五极耳52为多个且层叠设置。具体地，第五主体51包括第五电极组件5的正极涂覆区、隔膜P3和负极涂覆区。第五极耳52与第一极耳12的极性相同，在本实施例中，第五极耳52为第五电极组件5的负极空白区。
第五极耳52朝靠近第二极耳22的方向弯折并焊接于第二极耳22。具体地，第五极耳52可通过超声波焊接固定于第二延伸部221并形成第三熔接区W3。
在已知技术中，如果三个电极组件的极耳收拢在一起并同时焊接到转接片8，那么三个电极组件的极耳将会存在严重的错位；相比于两个电极组件，三个电极组件的极耳需要更大的长度。而在本申请中，第五极耳52只需要 焊接到第二延伸部221即可，无需焊接到第一极耳12或转接片8，因此，本申请可以有效地降低对极耳长度的要求。
在使用过程中，第一熔接区W1的电流会大于第三熔接区W3的电流；为满足过流要求和强度要求，第一熔接区W1的面积优选等于或大于第三熔接区W3的面积。
图10和图11为本申请的二次电池的第三实施例的示意图。与第二实施例相比，第三实施例将第三电极组件3和第四电极组件4省略。也就是说，第三实施例的二次电池仅包括第一电极组件1、第二电极组件2和第五电极组件5。
优选地，第三实施例的第五电极组件5为多个并沿远离第二电极组件2的方向依次设置，且各第五电极组件5的第五极耳52朝靠近第二极耳22的方向弯折。与第二电极组件2相邻的第五电极组件5的第五极耳52焊接于第二极耳22。除与第二电极组件2相邻的第五电极组件5外，其余的各第五电极组件5的第五极耳52焊接于相邻的第五电极组件5的第五极耳52。
与第二实施例相比，转接片8仅需与第一连接部122焊接即可，因此，转接片8的结构可以简化(例如去除第二部分82)，从而减小转接片8占用的空间。
图12和图13为本申请的二次电池的第四实施例的示意图。与第一实施例相比，第四实施例的极耳设置的位置不同。
具体地，多个第一极耳12位于第一电极组件1的厚度中心的靠近第二电极组件2的一侧，多个第二极耳22位于第二电极组件2的厚度中心的远离第一电极组件1的一侧。同时，多个第四极耳42位于第四电极组件4的厚度中心的靠近第三电极组件3的一侧，多个第三极耳32位于第三电极组件2的厚度中心的远离第四电极组件4的一侧。
与第一实施例相比，第四实施例可以减小第四极耳42和第一极耳12的间距，降低转接片8的第三部分83的延伸长度，节省物料。

Claims (10)

  1. 一种二次电池，包括第一电极组件(1)、第二电极组件(2)、壳体(6)以及顶盖组件(7)；
    第一电极组件(1)和第二电极组件(2)收容于壳体(6)内；
    顶盖组件(7)包括顶盖板(71)和第一电极端子(72)，顶盖板(71)连接于壳体(6)，第一电极端子(72)设置于顶盖板(71)；
    第一电极组件(1)包括第一主体(11)和从第一主体(11)延伸的第一极耳(12)，第一极耳(12)为多个且层叠设置；
    第二电极组件(2)包括第二主体(21)和从第二主体(21)延伸的第二极耳(22)，第二极耳(22)为多个且层叠设置；
    各第二极耳(22)朝靠近第一极耳(12)的方向弯折并连接于第一极耳(12)，且第二极耳(22)远离第二主体(21)的一端为第二端部(224)；
    各第一极耳(12)包括超出第二端部(224)的第一连接部(122)，且第一连接部(122)连接于第一电极端子(72)。
  2. 根据权利要求1所述的二次电池，其特征在于，
    各第一极耳(12)还包括第一延伸部(121)，第一延伸部(121)连接于第一连接部(122)与第一主体(11)之间，第二极耳(22)焊接于第一延伸部(121)。
  3. 根据权利要求2所述的二次电池，其特征在于，
    各第二极耳(22)还包括第二延伸部(221)和第二连接部(222)，第二延伸部(221)连接于第二主体(21)并朝靠近第一延伸部(121)的方向延伸，第二连接部(222)从第二延伸部(221)的远离第二主体(21)的一端延伸并焊接于第一延伸部(121)。
  4. 根据权利要求3所述的二次电池，其特征在于，多个第二极耳(22)的第二连接部(222)焊接于多个第一极耳(12)的第一延伸部(121)并形成第一熔接区(W1)。
  5. 根据权利要求4所述的二次电池，其特征在于，
    二次电池还包括转接片(8)，转接片(8)连接于第一电极端子(72)；
    多个第一极耳(12)的第一连接部(122)焊接于转接片(8)并形成第二熔接区(W2)，且第二熔接区(W2)的面积大于或等于第一熔接区(W1)的面积。
  6. 根据权利要求1所述的二次电池，其特征在于，
    多个第一极耳(12)位于第一电极组件(1)的厚度中心的一侧；
    多个第二极耳(22)位于第二电极组件(2)的厚度中心的一侧；
    第一极耳(12)和第二极耳(22)中的一个靠近第一电极组件(1)和第二电极组件(2)的交界面设置，第一极耳(12)和第二极耳(22)中的另一个远离第一电极组件(1)和第二电极组件(2)的交界面设置。
  7. 根据权利要求6所述的二次电池，其特征在于，第一极耳(12)位于第一电极组件(1)的厚度中心的远离所述交界面的一侧。
  8. 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收容于壳体(6)内的第三电极组件(3)和第四电极组件(4)，第一电极组件(1)、第二电极组件(2)、第三电极组件(3)和第四电极组件(4)依次排列；
    第三电极组件(3)包括第三主体(31)和从第三主体(31)延伸的第三极耳(32)，第三极耳(32)为多个且层叠设置；
    第四电极组件(4)包括第四主体(41)和从第四主体(41)延伸的第四极耳(42)，第四极耳(42)为多个且层叠设置；
    各第三极耳(32)朝靠近第四极耳(42)的方向弯折并连接于第四极耳(42)，且第三极耳(32)远离第三主体(31)的一端为第三端部(321)；
    各第四极耳(42)包括超出第三端部(321)的第四连接部(422)，且第四连接部(422)连接于第一电极端子(72)。
  9. 根据权利要求1或8所述的二次电池，其特征在于，
    所述二次电池还包括第五电极组件(5)，第五电极组件(5)收容于壳体(6)内，且第五电极组件(5)设置于第二电极组件(2)的远离第一电极组件(1)的一侧；
    第五电极组件(5)包括第五主体(51)和从第五主体(51)延伸的第五极耳(52)，第五极耳(52)朝靠近第二极耳(22)的方向弯折并焊接于第二极耳(22)。
  10. 根据权利要求9所述的二次电池，其特征在于，
    第五电极组件(5)为多个并沿远离第二电极组件(2)的方向依次设置，且各第五电极组件(5)的第五极耳(52)朝靠近第二极耳(22)的方向弯折；
    与第二电极组件(2)相邻的第五电极组件(5)的第五极耳(52)焊接于第二极耳(22)；
    除与第二电极组件(2)相邻的第五电极组件(5)外，其余的各第五电极组件(5)的第五极耳(52)焊接于相邻的第五电极组件(5)的第五极耳(52)。
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CN209401759U (zh) 2019-09-17
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