CN114614107A - Lithium ion battery and assembling method thereof - Google Patents

Lithium ion battery and assembling method thereof Download PDF

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Publication number
CN114614107A
CN114614107A CN202210383099.2A CN202210383099A CN114614107A CN 114614107 A CN114614107 A CN 114614107A CN 202210383099 A CN202210383099 A CN 202210383099A CN 114614107 A CN114614107 A CN 114614107A
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China
Prior art keywords
lithium ion
ion battery
positive
shell
tab
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Application number
CN202210383099.2A
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Chinese (zh)
Inventor
李乾坤
刘小安
刘玮勇
孙晓辉
孙新乐
许舟峰
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Svolt Energy Technology Co Ltd
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Svolt Energy Technology Co Ltd
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Priority to CN202210383099.2A priority Critical patent/CN114614107A/en
Publication of CN114614107A publication Critical patent/CN114614107A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • 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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/103—Primary casings; Jackets or wrappings characterised by their shape or physical structure prismatic or rectangular
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • H01M50/148—Lids or covers characterised by their shape
    • H01M50/15—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
    • H01M50/147—Lids or covers
    • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
    • H01M50/167—Lids or covers characterised by the methods of assembling casings with lids by crimping
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
    • H01M50/169—Lids or covers characterised by the methods of assembling casings with lids by welding, brazing or soldering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
    • H01M50/171—Lids or covers characterised by the methods of assembling casings with lids using adhesives or sealing agents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/172—Arrangements of electric connectors penetrating the casing
    • H01M50/174—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells
    • H01M50/176—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
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/536—Electrode connections inside a battery casing characterised by the method of fixing the leads to the electrodes, e.g. by welding
    • 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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/547—Terminals characterised by the disposition of the terminals on the cells
    • H01M50/55—Terminals characterised by the disposition of the terminals on the cells on the same side of the cell
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • 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

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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)
  • Connection Of Batteries Or Terminals (AREA)

Abstract

The application relates to the technical field of battery production, in particular to a lithium ion battery and an assembly method thereof. The assembly method of the lithium ion battery comprises the following steps: taking a positive plate with a positive plate tab formed at one end and a negative plate with a negative plate tab formed at one end, alternately superposing the multiple layers of positive plates and the multiple layers of negative plates to prepare a battery cell, connecting the positive plate tabs of the multiple layers of plates into a positive plate battery cell tab, and connecting the negative plate tabs of the multiple layers of plates into a negative plate battery cell tab; installing a positive pole column and a negative pole column on a first shell, placing a battery cell on the first shell, welding a positive pole core lug with the positive pole column, and welding a negative pole core lug with the negative pole column; and encapsulating the circumferential edge of the second shell and the circumferential edge of the first shell to obtain the lithium ion battery. The lithium ion battery is manufactured by the assembly method of the lithium ion battery. The assembling method of the lithium ion battery and the lithium ion battery can save assembling procedures and improve assembling efficiency.

Description

Lithium ion battery and assembling method thereof
Technical Field
The application relates to the technical field of battery production, in particular to a lithium ion battery and an assembly method thereof.
Background
The requirements on the manufacturing process of the lithium ion battery are gradually improved, and especially the requirements on the assembly efficiency are higher and higher. The lithium ion battery manufacturing process mainly comprises an electrode process part, an assembly process part and a formation process part. Among them, the assembly process generally includes tens of small processes, which is the most complicated, and thus becomes an important bottleneck that restricts the simplification of the battery manufacturing process.
At present, the two-end tab battery is provided, and for the two-end tab battery, the casing is arranged to comprise the second end casing corresponding to the two-end tabs respectively, and the upper casing and the lower casing corresponding to the upper surface and the lower surface of the battery respectively, so that the second end casing is welded with the tab on one side, then the battery is assembled with the upper casing and the lower casing, and then the second end casing is welded with the tab on the other side after the battery cell is placed into the casing.
Disclosure of Invention
The application aims to provide a lithium ion battery and an assembly method thereof, and solves the technical problems that the assembly of a battery with two end tab outlets is too complex and difficult and the efficiency is low in the prior art to a certain extent.
The application provides an assembly method of a lithium ion battery, which comprises the following steps:
assembling the battery cell: taking a positive plate with a positive plate tab formed at one end and a negative plate with a negative plate tab formed at one end, alternately superposing a plurality of layers of the positive plates and the plurality of layers of the negative plates in a mode that the positive plate tab is opposite to the negative plate tab to manufacture a battery core, connecting the plurality of layers of the positive plate tabs to form a positive plate tab, and connecting the plurality of layers of the negative plate tabs to form a negative plate tab;
assembling the first shell: installing a positive pole column and a negative pole column on a first shell, placing the battery cell on the first shell, welding a positive pole battery cell tab with the positive pole column, and welding a negative pole battery cell tab with the negative pole column;
assembling the second shell: and covering a second shell on the first shell, and encapsulating the circumferential edge of the second shell and the circumferential edge of the first shell to form a shell assembly to obtain the lithium ion battery.
In the above technical solution, further, before the step of assembling the second housing, the method further includes the following steps:
insulation treatment: and an insulating layer is arranged between the first shell and the battery core, and/or between the second shell and the battery core, and/or the anode battery core lug is opposite to the exposed surface of the anode pole, and/or the cathode battery core lug is opposite to the exposed surface of the cathode pole.
In any of the above technical solutions, further, the insulating layer is disposed on an inner surface of the first casing or a side surface of the battery cell facing the first casing, so as to be disposed between the first casing and the battery cell;
the insulating layer is provided on an inner surface of the second casing or on a side surface of the battery cell facing the second casing, so as to be provided between the second casing and the battery cell.
In any of the above technical solutions, further, the following steps are further included between the step of assembling the first housing and the step of assembling the second housing:
battery core positioning: and mounting a first positioning member and a second positioning member which are respectively abutted against two ends of the battery cell on the first shell so that the battery cell is positioned between the first positioning member and the second positioning member.
In any of the above technical solutions, further, the step of assembling the battery cell specifically includes the following steps:
forming an electric core: taking a positive plate with a positive pole piece tab formed at one end and a negative plate with a negative pole piece tab formed at one end, and alternately superposing a plurality of layers of the positive plates and a plurality of layers of the negative plates in a mode that the positive pole piece tab is opposite to the negative pole piece tab to manufacture a battery cell;
pre-welding a lug: and welding the multiple layers of the positive pole piece tabs along the superposition direction to form the positive pole electric core tabs, and welding the multiple layers of the negative pole piece tabs along the superposition direction to form the negative pole electric core tabs.
In any of the above technical solutions, further, the step of prewelding the tab specifically includes the following steps:
ultrasonic welding: welding a plurality of layers of the positive pole piece tabs along the overlapping direction by adopting an ultrasonic welding method, and welding a plurality of layers of the negative pole piece tabs along the overlapping direction by adopting the ultrasonic welding method;
and (4) cutting the allowance: and cutting the dislocation allowance generated after the multiple layers of the positive pole piece tabs are subjected to ultrasonic welding to obtain the positive pole core tabs, and cutting the dislocation allowance generated after the multiple layers of the negative pole piece tabs are subjected to ultrasonic welding to obtain the negative pole core tabs.
In any one of the above technical solutions, further, before the step of forming the battery core, the method further includes the following steps:
cutting a pole piece: and cutting one end of the positive plate to form the positive plate tab with the width inwards contracted or equal width at one end of the positive plate, and cutting one end of the negative plate to form the negative plate tab with the width inwards contracted or equal width at one end of the negative plate.
In any of the above technical solutions, further, the step of mounting the positive post and the negative post on the first housing specifically includes the following steps:
the middle part of the positive pole column and the middle part of the negative pole column are both provided with insulating parts, and the positive pole column and the negative pole column are both installed on the first shell in a mode that the insulating parts are contacted with the first shell, so that the two ends of the positive pole column and the two ends of the negative pole column respectively extend out of the inner surface and the outer surface of the first shell.
In any of the above technical solutions, further, the step of assembling the first housing further includes the following steps before the step of assembling the first housing:
one of the first case and the second case is shaped into a plate shape, and the other of the first case and the second case is shaped into a concave shape.
The application also provides a lithium ion battery which is manufactured by the assembly method of the lithium ion battery in any technical scheme.
In any of the above technical solutions, further, the length of the lithium ion battery is 200-2800mm, the width of the lithium ion battery is 90-300mm, and the thickness of the lithium ion battery is 10-60 mm;
the ratio of the length to the thickness of the lithium ion battery is 3-280.
In any of the above technical solutions, further, the leakage rate of the casing assembly of the lithium ion battery is a (unit 10^ -9Pa ^ m)3The lithium ion battery also comprises an explosion-proof valve arranged on the shell component, and the opening pressure of the explosion-proof valve is d (unit Mpa);
the leakage rate a of the shell assembly, the tensile strength b of the shell assembly, the compressive strength c of the shell assembly and the opening pressure d of the explosion-proof valve satisfy the following relations:
0.1≤(a*b)^2+(c*d)^2≤4648.5。
in any of the above technical solutions, further, the leakage rate a of the housing assembly has a value range of (0.002-0.2) × 10^ -9Pa ^ m3/s；
The value range of the tensile strength b of the shell assembly is 130-340 MPa;
the value range of the compressive strength c of the shell component is 0.3-2.6 Mpa;
the opening pressure d of the explosion-proof valve ranges from 0.6MPa to 1.9 MPa.
The application also provides a battery pack, and the lithium ion battery adopting any one of the technical schemes.
Compared with the prior art, the beneficial effects of this application do:
according to the assembling method of the lithium ion battery, the first shell, the positive pole column and the negative pole column are integrally assembled, the simultaneous welding operation of the positive pole and the negative pole is achieved, and only the first shell and the second shell need to be packaged once.
Compared with the scheme that the lug on one side is welded firstly and the lug on the other side is welded after the lug is placed into the shell in the prior art, the simultaneous welding of the anode and the cathode is realized, the time is saved, only one packaging process is needed, the assembly process is obviously saved, the assembly time is shortened, and the assembly efficiency is improved.
The lithium ion battery provided by the application is manufactured by the assembly method of the lithium ion battery, so that all beneficial effects of the lithium ion battery can be realized.
The battery pack provided by the embodiment includes the lithium ion battery, so that all the beneficial effects of the lithium ion battery can be realized.
Drawings
In order to more clearly illustrate the detailed description of the present application or the technical solutions in the prior art, the drawings needed to be used in the detailed description of the present application or the prior art description will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic view of a first structure of a battery cell obtained in a battery cell forming step provided in an embodiment of the present application;
fig. 2 is a second schematic structural diagram of a battery cell obtained in a battery cell forming step in an embodiment of the present application;
fig. 3 is a schematic view of a first structure of another battery cell obtained in a battery cell forming step in an embodiment of the present application;
fig. 4 is a second schematic structural diagram of another battery cell obtained in a battery cell forming step in the first embodiment of the present application;
fig. 5 is a schematic view of a first structure of another battery cell obtained in a battery cell forming step in an embodiment of the present application;
fig. 6 is a second schematic structural diagram of another battery cell obtained in the battery cell forming step in the first embodiment of the present application;
fig. 7 is a schematic structural diagram of a battery cell obtained in a step of prewelding a tab according to an embodiment of the present application;
fig. 8 is a schematic structural diagram of a component obtained after a step of mounting a positive electrode post and a negative electrode post on a first housing according to an embodiment of the present application;
FIG. 9 is a first structural diagram of a component obtained in a first housing assembling step according to an embodiment of the present disclosure;
fig. 10 is a second structural diagram of a component obtained in the first housing assembling step according to an embodiment of the present application;
fig. 11 is a schematic view of a first structure of a component obtained in a cell positioning and assembling step provided in an embodiment of the present application;
fig. 12 is a second schematic structural diagram of a component obtained in a cell positioning and assembling step provided in an embodiment of the present application;
fig. 13 is a schematic structural diagram of a lithium ion battery obtained in the second casing assembling step according to the first embodiment of the present application;
fig. 14 is a partial enlarged view of fig. 13 at the negative post;
fig. 15 is a partial enlarged view of fig. 13 at the positive post;
fig. 16 is a schematic structural diagram of a battery pack according to a third embodiment of the present application.
Reference numerals:
2-a first housing; 3-positive pole column; 300-inner positive post; 301-positive post insulator; 302-outer positive post; 4-a negative pole post; 400-inner negative pole; 401 — negative pole column insulation; 402-outer negative pole; 5-a second housing; 600-a first positioning member; 601-a second positioning member; 81-a first insulating layer; 82-a second insulating layer; 83-third insulating layer; 84-a fourth insulating layer; 85-a fifth insulating layer; 9-electric core; 90-positive core tab; 91-negative electrode core tab; 92-welding a positive electrode core lug to be welded; 93-welding a negative electrode core lug to be welded; 1-a battery pack; 100-lithium ion battery.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example one
Referring to fig. 1 to fig. 15 in combination with fig. 16, an embodiment of the present application provides an assembling method of a lithium ion battery 100, which is used for assembling a battery cell 9 with tabs at two ends, so as to achieve the purpose of saving an assembling process of such a battery cell 9.
The assembly method of the lithium ion battery 100 provided by the embodiment includes the following steps:
step S10, assembling the battery cell: taking a positive plate with one end formed with a positive pole plate tab and a negative plate with one end formed with a negative pole plate tab, alternately superposing a plurality of layers of the positive plates and the negative plates in a mode that the positive pole plate tab is opposite to the negative pole plate tab to manufacture a battery cell 9, connecting the plurality of layers of the positive pole plate tabs to form a positive pole battery cell tab 90, and connecting the plurality of layers of the negative pole plate tabs to form a negative pole battery cell tab 91;
step S11, first housing assembly: installing a positive pole post 3 and a negative pole post 4 on a first shell 2 to obtain a first shell 2 assembly, placing a battery cell 9 on the first shell 2, welding a positive pole tab 90 with the positive pole post 3, and welding a negative pole tab 91 with the negative pole post 4;
step S12, assembling the second housing: and covering the second shell 5 on the first shell 2, and encapsulating the circumferential edge of the second shell 5 and the circumferential edge of the first shell 2 to form a shell assembly to obtain the lithium ion battery 100.
In this alternative, the integrated assembly of the battery cell 9 is performed in step S10, the integrated assembly of the first case 2, the positive post 3, and the negative post 4 is performed in step S11, and the simultaneous welding operation of the positive and negative electrodes is performed, specifically, the positive electrode core tab 90 and the positive post 3 are welded at the same time, and the negative electrode core tab 91 and the negative post 4 are welded at the same time. In addition, only two parts of the first casing 2 and the second casing 5 need to be packaged in step S12, and the casing assembly includes the first casing 2 and the second casing 5 which are packaged all around.
Specifically, in step S10, multiple layers of positive plates and multiple layers of negative plates are alternately stacked to form the battery cell 9, and all the positive plate tabs are located at one end of the battery cell 9 and all the negative plate tabs are located at the other end of the battery cell 9, so that the positive plate tabs and the negative plate tabs of adjacent positive plates and negative plates are oppositely disposed.
Optionally, in step S10, the thickness of the positive electrode tab of the positive electrode sheet is selected to be 8-15 μm, and the thickness of the negative electrode tab of the negative electrode sheet is selected to be 8-15 μm, for example, 8 μm, 10 μm, 12 μm, or 15 μm. Further, the cell 9 is made by stacking multiple layers of pole pieces, and has a thickness of 10-30mm, such as 10mm, 15mm, 20mm, 25mm, or 30 mm.
Compared with the prior art that the tab on one side is welded firstly, and the tab on the other side is welded after the tab is placed into the shell, the simultaneous welding of the anode and the cathode is realized, the time is saved, the anode post 3 and the cathode post 4 are directly installed on the first shell 2 instead of being installed on the end cover plate respectively, so that only one-time packaging process is needed, the assembly process is obviously saved, the assembly time is shortened, and the assembly efficiency is improved.
In an alternative of this embodiment, the method for assembling the lithium ion battery 100 includes the following steps:
step S20, assembling the battery cell: taking a positive plate with a positive pole piece tab formed at one end and a negative plate with a negative pole piece tab formed at one end, alternately superposing a plurality of layers of positive plates and a plurality of layers of negative plates in a mode that the positive pole piece tab is opposite to the negative pole piece tab to manufacture a battery cell 9, connecting the positive pole piece tabs of the plurality of layers of pole pieces to form a positive pole battery cell tab 90, and connecting the negative pole piece tabs of the plurality of layers of pole pieces to form a negative pole battery cell tab 91;
step S21, insulation treatment: insulating layers are arranged between the first shell 2 and the battery cell 9, between the second shell 5 and the battery cell 9, on the exposed surface of the positive electrode core tab 90 relative to the positive electrode post 3 and on the exposed surface of the negative electrode core tab 91 relative to the negative electrode post 4;
step S22, first housing assembly: installing a positive pole post 3 and a negative pole post 4 on a first shell 2 to obtain a first shell 2 assembly, placing a battery cell 9 on the first shell 2, welding a positive pole tab 90 with the positive pole post 3, and welding a negative pole tab 91 with the negative pole post 4;
step S23, assembling the second housing: the second case 5 is covered on the first case 2, and the circumferential edge of the second case 5 and the circumferential edge of the first case 2 are encapsulated to obtain the lithium ion battery 100.
Specifically, the second insulating layer 82 is provided on a side surface of the battery cell 9 facing the first casing 2, or the fourth insulating layer 84 is provided on an inner surface of the first casing 2, so as to provide an insulating layer between the first casing 2 and the battery cell 9, that is, the second insulating layer 82 or the fourth insulating layer 84 serves as an insulating layer between the first casing 2 and the battery cell 9, thereby ensuring the safety of the battery cell 9 in use. Wherein, the inner surface of the first casing 2 refers to the surface of the first casing 2 for mounting the battery core 9, and the inner surface of the first casing 2 is inside the finally assembled lithium ion battery 100 and is not visible to a user, and the outer surface of the first casing 2 is outside the finally assembled lithium ion battery 100 and is visible to the user.
A first insulating layer 81 is provided on a side surface of the battery cell 9 facing the second casing 5, or a fifth insulating layer 85 is provided on an inner surface of the second casing 5, so as to provide an insulating layer between the second casing 5 and the battery cell 9, that is, the first insulating layer 81 or the fifth insulating layer 85 serves as an insulating layer between the second casing 5 and the battery cell 9, thereby ensuring the safety of the battery cell 9 in use. Similarly, the inner surface of the second casing 5 refers to the surface of the second casing 5 for mounting the battery cell 9, and the inner surface of the second casing 5 is not visible to the user in the finally assembled lithium ion battery 100, and the outer surface of the second casing 5 is visible to the user in the outside of the finally assembled lithium ion battery 100.
Third insulating layers 83 are respectively arranged on the exposed surface of the positive electrode core tab 90 relative to the positive electrode column 3 and the exposed surface of the negative electrode core tab 91 relative to the negative electrode column 4, so that the positive electrode core tab 90 and the negative electrode core tab 91 are subjected to external insulation protection through the third insulating layers 83.
Alternatively, the first insulating layer 81 and the second insulating layer 82 may be integrally molded.
Further, as for the method of forming the insulating layer, for example, it may be formed in the form of encapsulation, coating, or using an insulating separator, and specifically, for example, an insulating tape or an insulating glue.
Further, the insulating layer may be made of a material having an insulating shape such as mica, mylar, or PP, and may be made of an insulating material having a high heat insulating property so that the insulating layer has a heat insulating property.
Alternatively, the insulating layer is for example mylar film, mica sheet or PP encapsulation or the like.
Optionally, the insulating layer has a thickness of 0.05-0.1mm, e.g. 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09 mm.
In an alternative of this embodiment, the method for assembling the lithium ion battery 100 includes the following steps:
step S30, assembling the battery cell: taking a positive plate with a positive plate tab formed at one end and a negative plate with a negative plate tab formed at one end, alternately superposing a plurality of layers of positive plates and a plurality of layers of negative plates in a manner that the positive plate tab is opposite to the negative plate tab to manufacture a battery cell 9, connecting the plurality of layers of positive plate tabs to form a positive plate tab 90, and connecting the negative plate tabs of the plurality of layers of plates to form a negative plate tab 91;
step S31, insulation treatment: insulating layers are arranged between the first shell 2 and the battery cell 9, between the second shell 5 and the battery cell 9, on the exposed surface of the positive electrode core tab 90 relative to the positive electrode post 3 and on the exposed surface of the negative electrode core tab 91 relative to the negative electrode post 4;
step S32, first housing assembly: installing a positive pole post 3 and a negative pole post 4 on a first shell 2 to obtain a first shell 2 assembly, placing a battery cell 9 on the first shell 2, welding a positive pole tab 90 with the positive pole post 3, and welding a negative pole tab 91 with the negative pole post 4;
step S33, positioning the battery cell: a first positioning member 600 and a second positioning member 601 which are respectively abutted against both ends of the battery cell 9 are mounted on the first casing 2 so as to position the battery cell between the first positioning member 600 and the second positioning member 601;
step S34, assembling the second housing: the second case 5 is covered on the first case 2, and the circumferential edge of the second case 5 and the circumferential edge of the first case 2 are encapsulated to obtain the lithium ion battery 100.
In this alternative, in step S33, the first positioning member 600 and the second positioning member 601 are used to respectively position two ends (two ends connected with the positive electrode core tab 90 and the negative electrode core tab 91) of the electrical core 9 in the length direction, so as to prevent the electrical core 9 from moving relative to the first casing 2, and particularly prevent the electrical core 9 from accidentally moving inside the casing formed by the first casing 2 and the second casing 5 after the second casing is assembled, so as to protect the welding point between the positive electrode core tab 90 and the positive post 3 and the welding point between the negative electrode core tab 91 and the negative post 4, thereby prolonging the service life of the lithium ion battery 100.
Optionally, after the second casing 5 is covered on the first casing 2, along the length direction of the battery core 9, one end of each of the first positioning member 600 and the second positioning member 601 abuts against a side wall of the second casing 5, and the other end of each of the first positioning member 600 and the second positioning member 601 abuts against an end of the battery core 9.
In this embodiment, in order to improve positioning reliability, the first positioning members 600 are provided on both sides of the positive electrode core tab 90 in the width direction, and the second positioning members 601 are provided on both sides of the negative electrode core tab 91 in the width direction.
In an alternative of this embodiment, the method for assembling the lithium ion battery 100 includes the following steps:
step S40, forming the battery cell: taking a positive plate with a positive pole piece tab formed at one end and a negative plate with a negative pole piece tab formed at one end, and alternately superposing the multiple layers of positive plates and the multiple layers of negative plates in a manner that the positive pole piece tab is opposite to the negative pole piece tab to manufacture an electric core 9;
step S41, pre-welding the tabs: welding a plurality of layers of positive pole piece tabs along the superposition direction to form a positive pole electrode core tab 90, and welding a plurality of layers of negative pole piece tabs along the superposition direction to form a negative pole electrode core tab 91;
step S42, insulation treatment: insulating layers are arranged between the first shell 2 and the battery cell 9, between the second shell 5 and the battery cell 9, on the exposed surface of the positive electrode core tab 90 relative to the positive electrode post 3 and on the exposed surface of the negative electrode core tab 91 relative to the negative electrode post 4;
step S43, first housing assembly: installing a positive pole 3 and a negative pole 4 on a first shell 2 to obtain a first shell 2 assembly, placing a battery cell 9 on the first shell 2, welding a positive pole tab 90 with the positive pole 3, and welding a negative pole tab 91 with the negative pole 4;
step S44, positioning the battery cell: a first positioning member 600 and a second positioning member 601, which are respectively abutted against both ends of the battery cell 9, are mounted on the first casing 2 so that the battery cell is positioned between the first positioning member 600 and the second positioning member 601.
Step S45, assembling the second housing: the second case 5 is covered on the first case 2, and the circumferential edge of the second case 5 and the circumferential edge of the first case 2 are encapsulated to obtain the lithium ion battery 100.
Specifically, in step S40, the multilayer positive electrode tab of the cell 9 manufactured by stacking is used as the positive electrode core tab 92 to be welded, and the multilayer positive electrode tab of the cell 9 manufactured by stacking is used as the negative electrode core tab 93 to be welded.
Optionally, in step S40, 20 to 140 layers of pole pieces are stacked to form the battery cell 9, where the difference between the number of the positive pole pieces and the number of the negative pole pieces is 1 or-1, for example, 20 layers, 40 layers, 50 layers, 70 layers, 100 layers, 120 layers, 140 layers, and the like.
In step S41, the positive electrode tab 92 to be welded is welded, that is, the multiple layers of positive electrode tabs are connected in a welding manner to form a positive electrode tab 90; the negative electrode core tab 93 to be welded is welded, that is, the multiple layers of negative electrode core tabs are connected in a welding manner to form the negative electrode core tab 91.
Adopt the welded mode, can not only be can be under the prerequisite of the electric conductive property that remains utmost point ear, connect multilayer pole piece utmost point ear for 9 utmost point ears of electric core for electric core 9 can switch on with the external world through 9 utmost point ears of electric core, also can switch on mutually with utmost point post, specifically speaking, anodal electric core utmost point ear 90 switches on mutually with anodal post 3, and negative pole electric core utmost point ear 91 switches on mutually with negative pole post 4. And adopt the mode of welding, can also improve connection reliability and connection efficiency.
In an alternative of this embodiment, the method for assembling the lithium ion battery 100 includes the following steps:
step S50, forming the battery cell: taking a positive plate with a positive pole piece lug formed at one end and a negative plate with a negative pole piece lug formed at one end, and alternately superposing multiple layers of positive plates and multiple layers of negative plates in a mode that the positive pole piece lug is opposite to the negative pole piece lug to manufacture a battery cell 9;
step S51, pre-welding the tabs: welding a plurality of layers of positive pole piece tabs along the superposition direction to form a positive pole electrode core tab 90, and welding a plurality of layers of negative pole piece tabs along the superposition direction to form a negative pole electrode core tab 91;
step S52, ultrasonic welding: welding a plurality of layers of positive pole piece tabs along the overlapping direction by adopting an ultrasonic welding method, and welding a plurality of layers of negative pole piece tabs along the overlapping direction by adopting the ultrasonic welding method;
step S53, margin cutting: cutting the dislocation allowance generated after the ultrasonic welding of the multilayer positive pole piece lug to obtain a positive pole core lug 90, and cutting the dislocation allowance generated after the ultrasonic welding of the multilayer negative pole piece lug to obtain a negative pole core lug 91;
step S54, insulation treatment: insulating layers are arranged between the first shell 2 and the battery cell 9, between the second shell 5 and the battery cell 9, on the exposed surface of the positive electrode core tab 90 relative to the positive electrode post 3 and on the exposed surface of the negative electrode core tab 91 relative to the negative electrode post 4;
step S55, first housing assembly: installing a positive pole post 3 and a negative pole post 4 on a first shell 2 to obtain a first shell 2 assembly, placing a battery cell 9 on the first shell 2, welding a positive pole tab 90 with the positive pole post 3, and welding a negative pole tab 91 with the negative pole post 4;
step S56, positioning the battery cell: a first positioning member 600 and a second positioning member 601, which are respectively abutted against both ends of the battery cell 9, are attached to the first casing 2 so that the battery cell is positioned between the first positioning member 600 and the second positioning member 601.
Step S57, assembling the second housing: the second case 5 is covered on the first case 2, and the circumferential edge of the second case 5 and the circumferential edge of the first case 2 are encapsulated to obtain the lithium ion battery 100.
In steps S52 and S53, ultrasonic welding is performed by transmitting high-frequency vibration waves to the surfaces of two objects to be welded, and the surfaces of the two objects are rubbed against each other under pressure to form fusion between the molecular layers. That is to say, adopt ultrasonic bonding can make multilayer positive pole piece utmost point ear fuse layer by layer in the short time and form wholly, also obtain anodal electric core utmost point ear 90, and on the same way, adopt ultrasonic bonding can make multilayer negative pole piece utmost point ear fuse layer by layer in the short time and form wholly, also obtain negative pole electric core utmost point ear 91.
The ultrasonic welding is reliable and efficient, and the positive pole piece tab and the negative pole piece tab obtained after welding are obviously thinned and are easily connected with the pole.
After ultrasonic welding, the pole piece lugs on the upper layer are more obvious in collapse and dislocation due to the pressurization, so that the welding margins of the pole piece lugs in different levels are different, the edges of the pole lugs of the battery cell 9 obtained through the margin cutting step are regular, and the assembly requirements are met.
Optionally, the multilayer positive pole piece tabs are welded in the overlapping direction by an ultrasonic flat insection welding method, the multilayer negative pole piece tabs are welded in the overlapping direction by an ultrasonic flat insection welding method, the welding is efficient, the surface quality of the positive pole piece tabs obtained after welding and the surface quality of the negative pole piece tabs obtained after welding are both in a higher level, and the improvement of the welding quality of the tabs and the poles is facilitated.
Alternatively, ultrasonic welding may be accomplished using a single weld, the area of the single weld being 100 and 350mm2E.g. 100mm2、150mm2、200mm2、250mm2、300mm2Or 350mm2Etc.; alternatively, the ultrasonic welding may be performed by a plurality of welding impressions in a superposed or non-superposed manner, and when the plurality of welding impressions perform the ultrasonic welding in a superposed manner, the superposed distance may be 2-10mm, such as 2mm, 5mm, 8mm, or 10 mm.
In an alternative of this embodiment, the method for assembling the lithium ion battery 100 includes the following steps:
step S60, cutting the pole piece: cutting one end of the positive plate to form a positive plate tab with the width shrunk inwards or the same width, and cutting one end of the negative plate to form a negative plate tab with the width shrunk inwards or the same width;
step S61, forming the battery cell: taking a positive plate with a positive pole piece tab formed at one end and a negative plate with a negative pole piece tab formed at one end, and alternately superposing the multiple layers of positive plates and the multiple layers of negative plates in a manner that the positive pole piece tab is opposite to the negative pole piece tab to manufacture an electric core 9;
step S62, pre-welding the tabs: welding a plurality of layers of positive pole piece tabs along the superposition direction to form a positive pole electrode core tab 90, and welding a plurality of layers of negative pole piece tabs along the superposition direction to form a negative pole electrode core tab 91;
step S63, ultrasonic welding: welding a plurality of layers of positive pole piece tabs along the overlapping direction by adopting an ultrasonic welding method, and welding a plurality of layers of negative pole piece tabs along the overlapping direction by adopting the ultrasonic welding method;
step S64, margin trimming: cutting the dislocation allowance generated after the ultrasonic welding of the multilayer positive pole piece lug to obtain a positive pole core lug 90, and cutting the dislocation allowance generated after the ultrasonic welding of the multilayer negative pole piece lug to obtain a negative pole core lug 91;
step S65, insulation treatment: insulating layers are arranged between the first shell 2 and the battery cell 9, between the second shell 5 and the battery cell 9, on the exposed surface of the positive electrode core tab 90 relative to the positive electrode post 3 and on the exposed surface of the negative electrode core tab 91 relative to the negative electrode post 4;
step S66, first housing assembly: installing a positive pole post 3 and a negative pole post 4 on a first shell 2 to obtain a first shell 2 assembly, placing a battery cell 9 on the first shell 2, welding a positive pole tab 90 with the positive pole post 3, and welding a negative pole tab 91 with the negative pole post 4;
step S67, positioning the battery cell: a first positioning member 600 and a second positioning member 601, which are respectively abutted against both ends of the battery cell 9, are mounted on the first casing 2 so that the battery cell is positioned between the first positioning member 600 and the second positioning member 601.
Step S68, assembling the second housing: the second case 5 is covered on the first case 2, and the circumferential edge of the second case 5 and the circumferential edge of the first case 2 are encapsulated to obtain the lithium ion battery 100.
In step S60, it is determined according to the installation requirement whether the tab of the positive electrode tab is cut to have the same width as the positive electrode tab or the same width as the negative electrode tab, where the "width retraction" means that the tab has a width smaller than the width of the electrode tab, for example, the tab is semi-circular or trapezoidal. In step S61, the positive electrode sheets and the negative electrode sheets with the cut multi-layer tabs may be alternately stacked by winding or lamination.
In the alternative of this embodiment, the middle of the positive post 3 and the middle of the negative post 4 are insulated to form an insulating portion, and the positive post 3 and the negative post 4 are both mounted on the first housing 2 in such a manner that the insulating portion contacts the first housing 2, so that both ends of the positive post 3 and both ends of the negative post 4 respectively protrude out of the inner surface and the outer surface of the first housing 2.
Specifically, the positive post 3 includes a positive post insulating portion 301, and an inside positive post 300 and an outside positive post 302 that are connected, the positive post insulating portion 301 is sleeved on the joint of the inside positive post 300 and the outside positive post 302, the positive post 3 is inserted into the first casing 2 through the positive post insulating portion 301, so that the inside positive post 300 is located on the inner surface side of the first casing 2, and the outside positive post 302 is located on the outer surface side of the first casing 2. Optionally, the inner positive post 300 and the outer positive post 302 are riveted.
Negative pole 4 includes negative pole insulation part 401 and inboard negative pole 400 and the outside negative pole 402 that are connected, and negative pole insulation part 401 overcoat is in the junction of inboard negative pole 400 and outside negative pole 402, and negative pole 4 pegs graft mutually with first casing 2 through negative pole insulation part 401 to make inboard negative pole 400 be located the internal surface place side of first casing 2, outside negative pole 402 is located the surface place side of first casing 2. Optionally, the inner negative post 400 and the outer negative post 402 are riveted.
In an alternative of this embodiment, the method for assembling the lithium ion battery 100 includes the following steps:
step S70, cutting the pole piece: cutting one end of the positive pole piece to form a positive pole piece tab with the width being shrunk inwards or the same width at one end of the positive pole piece, and cutting one end of the negative pole piece to form a negative pole piece tab with the width being shrunk inwards or the same width at one end of the negative pole piece;
step S71, forming the battery cell: taking a positive plate with a positive pole piece tab formed at one end and a negative plate with a negative pole piece tab formed at one end, and alternately superposing the multiple layers of positive plates and the multiple layers of negative plates in a manner that the positive pole piece tab is opposite to the negative pole piece tab to manufacture an electric core 9;
step S72, pre-welding the tabs: welding a plurality of layers of positive pole piece tabs along the superposition direction to form a positive pole electrode core tab 90, and welding a plurality of layers of negative pole piece tabs along the superposition direction to form a negative pole electrode core tab 91;
step S73, ultrasonic welding: welding a plurality of layers of positive pole piece tabs along the overlapping direction by adopting an ultrasonic welding method, and welding a plurality of layers of negative pole piece tabs along the overlapping direction by adopting the ultrasonic welding method;
step S74, margin cutting: cutting the dislocation allowance generated after the multilayer positive pole piece lug is ultrasonically welded to obtain a positive pole electrode core lug 90, and cutting the dislocation allowance generated after the multilayer negative pole piece lug is ultrasonically welded to obtain a negative pole electrode core lug 91;
step S75, insulation treatment: insulating layers are arranged between the first shell 2 and the battery cell 9, between the second shell 5 and the battery cell 9, on the exposed surface of the positive electrode core tab 90 relative to the positive electrode post 3 and on the exposed surface of the negative electrode core tab 91 relative to the negative electrode post 4;
step S76 of molding one of the first case 2 and the second case 5 into a plate shape;
step S77, molding the other of the first case 2 and the second case 5 into a concave shape;
step S78, first housing assembly: installing a positive pole post 3 and a negative pole post 4 on a first shell 2 to obtain a first shell 2 assembly, placing a battery cell 9 on the first shell 2, welding a positive pole tab 90 with the positive pole post 3, and welding a negative pole tab 91 with the negative pole post 4;
step S79, positioning the battery cell: a first positioning member 600 and a second positioning member 601 which are respectively abutted against both ends of the battery cell 9 are mounted on the first casing 2 so as to position the battery cell between the first positioning member 600 and the second positioning member 601;
step S80, assembling the second housing: the second case 5 is covered on the first case 2, and the circumferential edge of the second case 5 and the circumferential edge of the first case 2 are encapsulated to obtain the lithium ion battery 100.
In steps S76 and S77, the first case 2 is shaped like a plate, and the second case 5 is shaped like a concave, specifically, the second case 5 is shaped like a concave, which means that the second case 5 includes a bottom plate and a circumferential side wall standing on the edge of the bottom plate, so that an accommodation space for accommodating the battery cell 9, the pole, and the positioning member is formed inside the second case 5, and an opening that can be closed by the first case 2 is formed.
Alternatively, in step S76 and step S77, the thickness of the first casing 2 and the thickness of the second casing 5 are 0.2 to 1mm, for example, 0.2mm, 0.5mm, 0.8mm, 1mm, or the like, respectively.
In this embodiment, the circumferential edge of the first casing 2 and the circumferential edge of the second casing 5 may be connected by welding, or by pop-top can packaging, or by peripheral edge-curl packaging, or by bonding with a molten adhesive. It is to be emphasized that the packing compression strength between the first casing 2 and the second casing 5 needs to satisfy 0.3 to 2.6Mpa, for example, 0.3Mpa, 0.5Mpa, 0.8Mpa, 1Mpa, 1.5Mpa, 1.8Mpa, 2Mpa, 2.3Mpa, or 2.6Mpa, and further, preferably not less than 1.2 Mpa.
Optionally, the positive post 3 and the positive core tab 90 are welded by laser welding, the negative post 4 and the negative core tab 91 are welded by laser welding, and the circumferential edge of the first casing 2 and the circumferential edge of the second casing 5 are welded by laser welding.
Example two
The second embodiment provides a lithium ion battery, which is manufactured by the assembly method of the lithium ion battery in the first embodiment, the technical features of the assembly method of the lithium ion battery disclosed in the first embodiment are also applicable to the second embodiment, and the technical features of the assembly method of the lithium ion battery disclosed in the first embodiment are not described repeatedly.
As shown in fig. 1 to 16, in an alternative of the present embodiment, the length of the lithium ion battery 100 is 200 and 2800mm, such as 200mm, 400mm, 600mm, 800mm, 100mm, 1400mm, 1800mm, 2200mm, 2500mm, or 2800 mm. When the length of the lithium ion battery 100 is not more than 800mm, the lithium ion battery 100 is a short blade battery; when the length of the lithium ion battery 100 is greater than 800mm, the lithium ion battery 100 is a long sheet battery.
In an alternative of this embodiment, the width of the lithium ion battery 100 is 90-300mm, for example, 90mm, 120mm, 150mm, 200mm, 250mm, or 300 mm.
In an alternative of this embodiment, the thickness of the lithium ion battery 100 is 10-60mm, such as 10mm, 20mm, 30mm, 40mm, 50mm, or 60 mm.
In an alternative of this embodiment, the ratio of the length to the thickness of the lithium ion battery 100 is 3 to 280, for example, 3, 10, 15, 20, 50, 80, 100, 150, 200, 250, or 280, and the grouping efficiency of the lithium ion battery 100 can be increased to 70% or more, thereby improving the heat dissipation performance and the safety performance of the lithium ion battery 100.
In an alternative aspect of this embodiment, the lithium ion battery 100 has a case assembly with a leak rate of a (unit of 10^ -9Pa ^ m)3And/s), the tensile strength of the housing assembly is b (unit Mpa), the compressive strength of the housing assembly is c (unit Mpa), and the lithium ion battery 100 further includes an explosion-proof valve disposed in the housing assembly, the opening pressure of the explosion-proof valve being d (unit Mpa).
The leakage rate a of the shell assembly, the tensile strength b of the shell assembly, the compressive strength c of the shell assembly and the opening pressure d of the explosion-proof valve satisfy the following relations: 0.1 ≤ (a × b) ^2+ (c × d) ^2 ≤ 4648.5.
Therefore, when the a, the b, the c and the d meet the relationship, the sealing performance and the structural strength of the shell assembly of the lithium ion battery 100 can be fully considered, and the opening performance of the explosion-proof valve is ensured, so that the use safety and the cycle service life of the lithium ion battery 100 are improved, and further, when the thermal runaway reaction occurs in the shell assembly, enough reaction time can be reserved for relevant personnel to evacuate timely.
In this embodiment, the leakage rate a of the housing assembly has a value range of (0.002-0.2) × 10^ -9Pa ^ m3S, e.g. 0.002 x 10-9 Pa x m3/s、0.02*10^-9Pa*m3/s、0.05*10^-9Pa*m3/s、0.1*10^-9Pa*m3/s、0.5*10^-9Pa*m3(ii)/s or 0.2 x 10-9 Pa x m3And s. Wherein the leakage rate a of the housing assembly is not less than 0.002 x 10-9 Pa x m3S, ensuring sufficient sealing performance of the housing assembly and avoiding the housing assemblyThe inner positive pole piece or the negative pole piece is in contact with the air outside the shell assembly to cause thermal runaway. Limiting the leak rate a of the housing assembly to not more than 0.2 x 10-9 Pa x m for cost control of the housing assembly3/s。
Optionally, the positive electrode plate is made of lithium cobaltate, a ternary material, lithium iron phosphate, lithium manganate or the like, and the negative electrode plate is made of natural graphite, soft carbon, a silicon-based material, an alloy material, a tin-gold material or the like.
The tensile strength b of the shell assembly ranges from 130Mpa to 340Mpa, such as 130Mpa, 200Mpa, 250Mpa, 300Mpa or 340 Mpa. Wherein, by limiting the tensile strength b of the housing assembly to not less than 130Mpa, the housing assembly can be ensured to have sufficient tensile strength, so that when the battery pack 1 including the lithium ion battery 100 is applied to a scene such as a vehicle, the risk of deformation of the housing assembly due to collision or the like can be effectively avoided. The tensile strength b of the housing assembly is defined to be not more than 340Mpa in view of controlling the cost of the housing assembly.
The compressive strength c of the shell component ranges from 0.3 to 2.6Mpa, such as 0.3Mpa, 0.8Mpa, 1.2Mpa, 1.6Mpa, 2Mpa or 2.6 Mpa. Wherein, by limiting the compression strength c of the housing assembly to not less than 0.3Mpa, it can be ensured that the housing assembly is not punctured by the accumulation of lithium ions inside, and the sealing performance of the housing assembly is improved. The compressive strength c of the housing assembly is defined to be not more than 2.6Mpa in view of controlling the cost of the housing assembly.
The opening pressure d of the explosion-proof valve ranges from 0.6Mpa to 1.9Mpa, for example, 0.6Mpa, 1Mpa, 1.5Mpa or 1.9Mpa, which can prevent the internal pressure of the housing assembly from being too high due to the accumulation of gas inside the housing assembly, thereby preventing the lithium ion battery 100 from exploding.
Alternatively, explosion-proof valves are provided at both ends of the housing assembly in the longitudinal direction, that is, both ends where the positive and negative posts 3 and 4 are installed. The lithium ion battery in the present embodiment has the advantages of the method for assembling a lithium ion battery in the first embodiment, and the advantages of the method for assembling a lithium ion battery disclosed in the first embodiment are not described again here.
EXAMPLE III
The third embodiment provides a battery pack 1, which includes the lithium ion battery 100 in the second embodiment, and the technical features of the lithium ion battery 100 disclosed in the second embodiment are also applicable to this embodiment, and the technical features of the lithium ion battery 100 disclosed in the second embodiment are not described repeatedly.
In an alternative of this embodiment, as shown in fig. 16 in combination with fig. 1 to fig. 15, the battery pack 1 may include a plurality of lithium ion batteries 100 connected in series in order to meet the power demand of the corresponding power utilization scenario. The length direction of the lithium ion battery 100 is indicated by a bidirectional arrow e, and the length direction of the lithium ion battery 100 is consistent with the length direction of a single pole piece; the width direction of the lithium ion battery 100 is indicated by a double-headed arrow f, and the width direction of the lithium ion battery 100 is consistent with the width direction of a single pole piece; the thickness direction of the lithium ion battery 100 is indicated by a double-headed arrow g, and the thickness direction of the lithium ion battery 100 coincides with the stacking direction of the multilayer pole pieces.
The lithium ion battery 100 in the present embodiment has the advantages of the lithium ion battery 100 in the second embodiment, and the advantages of the lithium ion battery 100 in the second embodiment are not described repeatedly herein.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention. Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Claims (14)

1. A method for assembling a lithium ion battery, comprising the steps of:
assembling the battery cell: taking a positive plate with a positive plate tab formed at one end and a negative plate with a negative plate tab formed at one end, alternately superposing a plurality of layers of the positive plates and the plurality of layers of the negative plates in a mode that the positive plate tab is opposite to the negative plate tab to manufacture a battery core, connecting the plurality of layers of the positive plate tabs to form a positive plate tab, and connecting the plurality of layers of the negative plate tabs to form a negative plate tab;
assembling the first shell: installing a positive pole column and a negative pole column on a first shell, placing the battery cell on the first shell, welding a positive pole battery cell tab with the positive pole column, and welding a negative pole battery cell tab with the negative pole column;
assembling the second shell: and covering a second shell on the first shell, and encapsulating the circumferential edge of the second shell and the circumferential edge of the first shell to form a shell assembly to obtain the lithium ion battery.
2. The method of assembling a lithium ion battery of claim 1, further comprising, before the step of assembling the second housing, the steps of:
insulation treatment: and an insulating layer is arranged between the first shell and the battery core, and/or between the second shell and the battery core, and/or the anode battery core lug is opposite to the exposed surface of the anode pole, and/or the cathode battery core lug is opposite to the exposed surface of the cathode pole.
3. The method of assembling a lithium-ion battery according to claim 2, wherein the insulating layer is provided on an inner surface of the first casing or on a side surface of the cell that faces the first casing, so as to be provided between the first casing and the cell;
the insulating layer is provided on an inner surface of the second casing or on a side surface of the battery cell facing the second casing, so as to be provided between the second casing and the battery cell.
4. The method of assembling a lithium ion battery of claim 1, further comprising, between the step of assembling the first casing and the step of assembling the second casing, the steps of:
battery core positioning: and mounting a first positioning member and a second positioning member which are respectively abutted against two ends of the battery cell on the first shell so that the battery cell is positioned between the first positioning member and the second positioning member.
5. The assembly method of the lithium ion battery according to claim 1, wherein the step of assembling the battery cell specifically includes the steps of:
forming an electric core: taking a positive plate with a positive pole piece tab formed at one end and a negative plate with a negative pole piece tab formed at one end, and alternately superposing a plurality of layers of the positive plates and a plurality of layers of the negative plates in a mode that the positive pole piece tab is opposite to the negative pole piece tab to manufacture a battery cell;
pre-welding the lugs: and welding the multiple layers of the positive pole piece tabs along the superposition direction to form the positive pole electric core tabs, and welding the multiple layers of the negative pole piece tabs along the superposition direction to form the negative pole electric core tabs.
6. The assembly method of the lithium ion battery according to claim 4, wherein the step of prewelding the tab specifically comprises the steps of:
ultrasonic welding: welding a plurality of layers of the positive pole piece tabs along the overlapping direction by adopting an ultrasonic welding method, and welding a plurality of layers of the negative pole piece tabs along the overlapping direction by adopting an ultrasonic welding method;
and (4) cutting the allowance: and cutting the dislocation allowance generated after the multiple layers of the positive pole piece tabs are subjected to ultrasonic welding to obtain the positive pole core tabs, and cutting the dislocation allowance generated after the multiple layers of the negative pole piece tabs are subjected to ultrasonic welding to obtain the negative pole core tabs.
7. The method for assembling a lithium ion battery according to claim 5, wherein the step of forming the cell further comprises the following steps:
cutting a pole piece: and cutting one end of the positive plate to form the positive plate tab with the width inwards contracted or equal width at one end of the positive plate, and cutting one end of the negative plate to form the negative plate tab with the width inwards contracted or equal width at one end of the negative plate.
8. The method for assembling a lithium ion battery according to claim 1, wherein the step of mounting the positive electrode tab and the negative electrode tab on the first case specifically comprises the steps of:
the middle part of the positive pole column and the middle part of the negative pole column are both provided with insulating parts, and the positive pole column and the negative pole column are both installed on the first shell in a mode that the insulating parts are contacted with the first shell, so that the two ends of the positive pole column and the two ends of the negative pole column respectively extend out of the inner surface and the outer surface of the first shell.
9. The method of assembling a lithium ion battery of claim 1, wherein the step of assembling the first housing further comprises the steps of:
one of the first case and the second case is shaped into a plate shape, and the other of the first case and the second case is shaped into a concave shape.
10. A lithium ion battery produced by the method for assembling a lithium ion battery according to any one of claims 1 to 9.
11. The lithium ion battery of claim 10, wherein the length of the lithium ion battery is 200-2800mm, the width of the lithium ion battery is 90-300mm, and the thickness of the lithium ion battery is 10-60 mm;
the ratio of the length to the thickness of the lithium ion battery is 3-280.
12. The lithium ion battery of claim 11, wherein the housing assembly of the lithium ion battery has a leak rate of a (in units of 10-9 Pa x m)3The lithium ion battery also comprises an explosion-proof valve arranged on the shell component, and the opening pressure of the explosion-proof valve is d (unit Mpa);
the leakage rate a of the shell assembly, the tensile strength b of the shell assembly, the compressive strength c of the shell assembly and the opening pressure d of the explosion-proof valve satisfy the following relations:
0.1≤(a*b)^2+(c*d)^2≤4648.5。
13. the lithium ion battery of claim 12,
the value range of the leakage rate a of the shell component is (0.002-0.2) 10^ -9Pa ^ m3/s；
The value range of the tensile strength b of the shell assembly is 130-340 MPa;
the value range of the compressive strength c of the shell component is 0.3-2.6 Mpa;
the opening pressure d of the explosion-proof valve ranges from 0.6MPa to 1.9 MPa.
14. A battery pack comprising the lithium ion battery of any one of claims 10 to 13.
CN202210383099.2A 2022-04-12 2022-04-12 Lithium ion battery and assembling method thereof Pending CN114614107A (en)

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