CN114242944A - Negative plate component, battery core, preparation method of battery core and laminated battery - Google Patents

Negative plate component, battery core, preparation method of battery core and laminated battery Download PDF

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Publication number
CN114242944A
CN114242944A CN202210041387.XA CN202210041387A CN114242944A CN 114242944 A CN114242944 A CN 114242944A CN 202210041387 A CN202210041387 A CN 202210041387A CN 114242944 A CN114242944 A CN 114242944A
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negative
negative electrode
copper foil
positive
tab
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史金元
邓健想
刘长昊
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Fullymax Battery Co ltd
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Fullymax Battery Co ltd
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Priority to CN202210041387.XA priority Critical patent/CN114242944A/en
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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
    • 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
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • 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
    • 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
    • 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
    • H01M50/538—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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

The application provides a negative plate assembly, a battery cell, a preparation method of the battery cell and a laminated battery. The negative pole piece assembly comprises a plurality of negative pole pieces, each negative pole piece comprises a copper foil piece, a negative pole lug and an auxiliary pole lug, the negative pole lugs and the corresponding auxiliary pole lugs are connected with the corresponding copper foil pieces, the negative pole lugs of the negative pole pieces are connected in a stacked mode, and the auxiliary pole lugs of the negative pole pieces are connected in a stacked mode. The negative plate component can reduce the thermal runaway inside the battery core of the lithium battery cell, and further improve the use safety of the lithium battery.

Description

Negative plate component, battery core, preparation method of battery core and laminated battery
Technical Field
The invention relates to the technical field of batteries, in particular to a negative plate assembly, a battery core, a preparation method of the battery core and a laminated battery.
Background
The lithium battery has the advantages of high energy density, good cycle performance and long service life, and is widely applied to products such as electric equipment, electric appliances, intelligent machines and the like, but the lithium battery has a more severe safety problem, namely, the lithium battery has an internal short circuit, which causes the problem of thermal runaway of a battery core of the lithium battery, especially, electrochemical reactions continuously occur inside the battery core of the lithium battery, the electrochemical reactions also accompany with heat release, wherein the temperature rise of a tab position is the most serious, and in the preparation process of the lithium battery, the tab is easily interfered by the outside to break.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a negative plate assembly, a battery cell, a preparation method of the negative plate assembly and the battery cell, and a laminated battery, wherein the negative plate assembly can reduce thermal runaway inside the battery cell of a lithium battery so as to improve the use safety of the lithium battery.
The purpose of the invention is realized by the following technical scheme:
the utility model provides a negative pole piece subassembly, includes a plurality of negative pole pieces, each the negative pole piece includes copper foil, negative pole ear and assists the utmost point ear, the negative pole ear with correspond assist utmost point ear all with correspond copper foil connects, a plurality of the negative pole piece the negative pole ear is range upon range of to be connected, and is a plurality of the negative pole piece assist utmost point ear range upon range of to be connected.
In one embodiment, the negative electrode tabs of the plurality of negative electrode sheets are welded together in a stacked manner.
In one embodiment, the auxiliary electrode tabs of the plurality of negative electrode sheets are welded together in a stacked manner.
In one embodiment, the negative electrode tab assembly further includes a plurality of nickel layers, the plurality of nickel layers are connected to the negative electrode tabs of the plurality of negative electrode tabs in a one-to-one correspondence, and each nickel layer is wound on the negative electrode tab of the corresponding negative electrode tab.
In one embodiment, the negative electrode tab and the auxiliary electrode tab are disposed on the same side of the copper foil.
In one embodiment, the negative electrode tab and the auxiliary electrode tab are oppositely arranged at two sides of the copper foil.
An electric core comprises the negative pole piece assembly in any one of the above embodiments, and further comprises a diaphragm and a plurality of positive pole pieces, wherein the copper foils of the plurality of negative pole pieces and the plurality of positive pole pieces are alternately stacked in a one-to-one correspondence manner, and the diaphragm is arranged between each positive pole piece and the copper foil of the adjacent negative pole piece.
In one embodiment, each positive plate includes an aluminum foil and a positive tab, the positive tabs of the positive plates are connected in a stacked manner, the aluminum foils of the positive plates and the copper foils of the negative plates are alternately stacked in a one-to-one correspondence manner, and the separator is disposed between the aluminum foil of each positive plate and the copper foil of the adjacent negative plate.
A method for preparing a battery cell, configured to prepare the battery cell according to any of the embodiments above, where the method for preparing the battery cell includes the following steps:
obtaining a copper foil piece to be processed, a diaphragm and a positive plate;
cutting the copper foil to be processed to integrally form the negative electrode lug and the auxiliary electrode lug on the copper foil to obtain a negative electrode sheet;
carrying out stacking connection operation on the diaphragm, the plurality of negative plates and the plurality of positive plates so that the copper foils of the plurality of negative plates and the plurality of positive plates are alternately stacked in a one-to-one correspondence manner, and the diaphragm is arranged between each positive plate and the copper foil of the adjacent negative plate to obtain a semi-finished product of the battery core;
and carrying out tab connection operation on the semi-finished product of the battery cell to obtain the battery cell.
A laminated battery includes the battery cell of any of the above embodiments, and further includes an electrolyte and a case, the electrolyte is filled in the case, the battery cell is disposed in the case, and the battery cell is soaked in the electrolyte.
Compared with the prior art, the invention has at least the following advantages:
according to the negative plate assembly, the negative electrode tabs and the corresponding auxiliary electrode tabs are connected with the corresponding copper foils, the negative electrode tabs of the negative electrode plates are connected in a stacked mode, the auxiliary electrode tabs of the negative electrode plates are connected in a stacked mode, and when partial negative electrode tabs of the negative electrode plates are broken, the copper foils of the negative electrode plates are still connected with the whole negative plate assembly due to the existence of the auxiliary electrode tabs on the negative electrode plates, so that the problem that the copper foils of partial negative electrode plates are oxidized due to the fact that the copper foils are in high potential, namely, the problem that the copper foils are oxidized due to the fact that the corresponding copper foils are in high potential after the negative electrode tabs of partial negative electrode plates are broken, and further the problem that the internal short circuit of a battery cell is caused to cause thermal runaway is solved, the thermal runaway of the battery cell containing the negative electrode plate assembly is effectively relieved, and the use safety of the battery cell containing the negative electrode plate assembly is effectively improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic structural view of a negative electrode tab assembly according to an embodiment of the present invention;
fig. 2 is a schematic view of a negative electrode sheet of the negative electrode sheet assembly shown in fig. 1;
fig. 3 is another schematic view of the negative electrode tab assembly shown in fig. 1;
fig. 4 is a schematic structural diagram of a battery cell according to an embodiment of the invention;
fig. 5 is a schematic structural diagram of a battery cell according to another embodiment of the present invention;
fig. 6 is a flowchart of a method for manufacturing a battery cell according to an embodiment of the present invention.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The application provides a negative plate assembly. The negative pole piece assembly comprises a plurality of negative pole pieces, each negative pole piece comprises a copper foil piece, a negative pole lug and an auxiliary pole lug, the negative pole lugs and the corresponding auxiliary pole lugs are connected with the corresponding copper foil pieces, the negative pole lugs of the negative pole pieces are connected in a stacked mode, and the auxiliary pole lugs of the negative pole pieces are connected in a stacked mode.
The negative pole piece assembly is characterized in that the negative pole lugs and the corresponding auxiliary pole lugs are connected with the corresponding copper foils, the negative pole lugs of the negative pole pieces are connected in a stacked mode, the auxiliary pole lugs of the negative pole pieces are connected in a stacked mode, after the negative pole lugs of part of the negative pole pieces break, due to the existence of the auxiliary pole lugs on the negative pole pieces, the copper foils of the negative pole pieces are still connected together in the whole negative pole piece assembly, the situation that the copper foils of part of the negative pole pieces are in high potential and are oxidized is avoided, namely, the situation that the corresponding copper foils after the negative pole lugs of part of the negative pole pieces break are in high potential is avoided, the copper foils are oxidized, the problem that the electric core is in thermal runaway due to internal short circuit of the battery is caused, the thermal runaway of the electric core containing the negative pole piece assembly is effectively relieved, and the use safety of the electric core containing the negative pole piece assembly is effectively improved.
Referring to fig. 1, 2 and 3 together, in order to better understand the negative electrode sheet assembly 10 of the present application, the negative electrode sheet assembly 10 of the present application is further explained below, in which the negative electrode sheet assembly 10 of an embodiment includes a plurality of negative electrode sheets 100, each negative electrode sheet 100 includes a copper foil 110, a negative electrode tab 120 and an auxiliary electrode tab 130, the negative electrode tabs 120 and the corresponding auxiliary electrode tabs 130 are connected to the corresponding copper foils 110, the negative electrode tabs 120 of the plurality of negative electrode sheets 100 are connected in a stacked manner, and the auxiliary electrode tabs 130 of the plurality of negative electrode sheets 100 are connected in a stacked manner.
In the negative electrode tab assembly 10, the negative electrode tabs 120 and the corresponding auxiliary electrode tabs 130 are connected to the corresponding copper foil 110, the negative electrode tabs 120 of the negative electrode tabs 100 are connected in a stacked manner, the auxiliary electrode tabs 130 of the negative electrode tabs 100 are connected in a stacked manner, when the negative electrode tab 120 of a part of the negative electrode sheet 100 is broken, due to the existence of the auxiliary electrode tab 130 on the negative electrode sheet 100, so that the copper foil 110 of the negative electrode sheet 100 is still connected to the whole negative electrode sheet assembly 10, thereby preventing the copper foil 110 of a part of the negative electrode sheet 100 from being oxidized due to high potential, namely, the situation that when part of the negative electrode tabs 120 of the negative electrode sheet 100 are broken, the corresponding copper foil 110 is at a high potential, so that the copper foil 110 is oxidized, and then cause the inside short circuit of battery and lead to the thermal runaway problem of electric core, alleviateed the thermal runaway of the electric core that contains this negative pole piece subassembly 10 effectively, and then improved the safety in utilization of the electric core that contains this negative pole piece subassembly 10 effectively.
It should be noted that, because the auxiliary tab does not play a role of being electrically connected with an external component, the auxiliary tab can be directly arranged in the shell of the battery, the problem that the auxiliary tab is interfered by the outside world and breaks is avoided, the electrical connection of each negative plate in the negative plate assembly is effectively ensured, the copper foil piece corresponding to the broken negative tab of a part of negative plates is better ensured to be at a high potential, the copper foil piece is oxidized, the problem that the thermal runaway of the battery core is caused by the internal short circuit of the battery is effectively avoided, the thermal runaway of the battery core containing the negative plate assembly is effectively reduced, and the use safety of the battery core containing the negative plate assembly is effectively improved.
Referring to fig. 1, in one embodiment, the negative electrode tabs 120 of the plurality of negative electrode tabs 100 are welded together in a stacked manner, so as to better ensure the connection stability and effectiveness of each negative electrode tab 100 and the component.
Referring to fig. 1, in one embodiment, the auxiliary tabs 130 of the negative electrode plates 100 are welded together in a stacked manner, so as to better ensure stable and firm connection of the negative electrode tabs 120 of each negative electrode plate 100, further ensure effective reduction of thermal runaway of a battery cell containing the negative electrode plate assembly 10, and effectively improve the use safety of the battery cell containing the negative electrode plate assembly 10.
In one embodiment, the negative electrode sheet assembly further comprises a plurality of nickel layers, the plurality of nickel layers are connected with the negative electrode tabs of the plurality of negative electrode sheets in a one-to-one correspondence manner, and each nickel layer is wound on the corresponding negative electrode tab of the negative electrode sheet, so that the electrochemical polarization at the negative electrode tab can be effectively reduced, the temperature rise of the battery cell containing the negative electrode sheet assembly is slowed down, and the safety performance of the battery cell containing the negative electrode sheet assembly is improved.
Referring to fig. 1 and 2, in one embodiment, the negative tab 120 and the auxiliary tab 130 are disposed on the same side of the copper foil 110. It can be understood that if the positive tab and the negative tab 120 are located at the same side position of the battery cell, the auxiliary tab 130 and the negative tab 120 are set at the same side position of the battery cell, so that the packaging difficulty of the battery cell is reduced, and the packaging efficiency of the battery cell is increased.
Referring to fig. 3, in one embodiment, the negative tab 120 and the auxiliary tab 130 are disposed opposite to each other on two sides of the copper foil 110. It can be understood that if the positive tab and the negative tab 120 are respectively located at two opposite side positions of the electrical core, the auxiliary tab 130 and the negative tab 120 may be located at the same side position of the electrical core or at two opposite side positions of the electrical core, the size specification of the auxiliary tab 130 at this time may be limited by the negative tab 120 or the positive tab, and the location where the auxiliary tab 130 is located at this time has a small influence on the difficulty of packaging the electrical core; however, if the positive tab and the negative tab 120 are located at the same lateral position of the battery cell, when the negative tab 120 and the negative tab 120 are respectively and oppositely disposed at the two lateral positions of the battery cell, the dimension of the auxiliary tab 130 is not affected by the positive tab and the negative tab 120, so that the dimension of the auxiliary tab 130 has a better adjustment space, and the battery cell has better charge-discharge rate performance due to the larger dimension of the auxiliary tab 130.
Referring to fig. 4 and 5, the present application further provides a battery cell 10A. The battery cell 10A includes the negative electrode plate assembly 10 of any one of the above embodiments, and further includes a separator 20 and a plurality of positive electrode plates 30, the copper foil pieces 110 of the negative electrode plates 100 and the positive electrode plates 30 are alternately stacked in a one-to-one correspondence, and the separator 20 is disposed between each positive electrode plate 30 and the copper foil piece 110 of the adjacent negative electrode plate 100. In the present embodiment, the negative electrode sheet assembly 10 includes a plurality of negative electrode sheets 100, each negative electrode sheet 100 includes a copper foil 110, a negative electrode tab 120 and an auxiliary electrode tab 130, the negative electrode tabs 120 and the corresponding auxiliary electrode tabs 130 are connected to the corresponding copper foil 110, the negative electrode tabs 120 of the plurality of negative electrode sheets 100 are connected in a stacked manner, and the auxiliary electrode tabs 130 of the plurality of negative electrode sheets 100 are connected in a stacked manner.
The above-mentioned battery cell 10A adopts the negative electrode plate assembly 10, and the negative electrode tab 120 and the corresponding auxiliary electrode tab 130 in the negative electrode plate 100 are connected with the corresponding copper foil 110, the negative electrode tabs 120 of the negative electrode plates 100 are connected in a stacked manner, the auxiliary electrode tabs 130 of the negative electrode plates 100 are connected in a stacked manner, the copper foil 110 of the negative electrode plates 100 and the positive electrode plates 30 are matched in a one-to-one alternate stacked manner, the diaphragm 20 is arranged between each positive electrode plate 30 and the copper foil 110 of the adjacent negative electrode plate 100, the thermal runaway of the battery cell 10A is effectively reduced, and the use safety of the battery cell 10A containing the negative electrode plate assembly 10 is effectively improved.
Referring to fig. 4 and 5, in one embodiment, each positive electrode sheet 30 includes an aluminum foil and a positive electrode tab 310, the positive electrode tabs 310 of the positive electrode sheets 30 are connected in a stacked manner, the aluminum foils of the positive electrode sheets 30 and the copper foils 110 of the negative electrode sheets 100 are alternately stacked in a one-to-one correspondence manner, and the separator 20 is disposed between the aluminum foil of each positive electrode sheet 30 and the copper foil 110 of the adjacent negative electrode sheet 100. It can be understood that the aluminum foils of the positive plates 30 and the copper foils 110 of the negative plates 100 are alternately stacked in a one-to-one correspondence, and the separator 20 is disposed between the aluminum foil of each positive plate 30 and the copper foil 110 of the adjacent negative plate 100, so that the insulating stacked arrangement of the negative tab 120 and the positive plate 30 is ensured, and the quality of the battery cell 10A is further ensured.
Referring to fig. 4 and 5, in one embodiment, the battery cell further includes a negative tab adhesive 40, the negative tab adhesive 40 is disposed around the negative tab 120, and the negative tab adhesive 40 is sandwiched between the negative tab 120 and the casing. It is to be understood that the negative electrode tab 40 serves to facilitate the insulating connection of the negative electrode tab 120 to the battery case, and the negative electrode tab 120 serves to assist in the encapsulation of the battery cell 10A.
In one embodiment, the negative electrode tab glue comprises insulating glue and heat-conducting silica gel. It can be understood, because the resistance of lug vicinity region is less, in battery charge-discharge process, the current density of lug is great, electrochemistry polarization is great, the temperature rise of negative pole lug department is very fast promptly, and be connected in order to make the shell insulation of negative pole lug and battery, need set up negative pole lug glue in negative pole lug periphery, and the general thermal conductivity of negative pole lug glue is relatively poor, further aggravate the rapid rise of the temperature of negative pole lug department, therefore, in this application, make the negative pole lug glue including insulating glue and heat conduction silica gel, the heat conductivility of negative pole lug glue has been increased, the quick heat dissipation of negative pole lug department has been realized effectively, and then the charge-discharge rate of battery has been improved effectively.
Referring to fig. 4 and fig. 5, in one embodiment, the battery core includes a positive tab glue 50, the positive tab glue 50 is sleeved on the periphery of the positive tab 310, and the positive tab glue 50 is sandwiched between the positive tab 310 and the casing, so as to ensure the insulating connection between the positive tab 310 and the casing of the battery, and further ensure the quality of the battery.
In one embodiment, the positive plate further comprises a positive substrate and positive slurry, the positive slurry is coated on the positive substrate, and the positive tab is connected with the positive substrate. It can be understood that structurally adjusting at electric core is with under the condition of lightening electric core thermal runaway, and the effect that only structurally improves the charge and discharge multiplying power and the cycle performance of electric core from electric core is limited, and starts from the electrode thick liquids, can realize electric core charge and discharge multiplying power and cycle performance's improvement betterly, especially starts from positive pole thick liquids to cooperate electric core structure, can be more effectively under the condition of lightening electric core thermal runaway, improve the charge and discharge multiplying power and the cycle performance of electric core.
In one embodiment, the positive electrode slurry comprises a positive electrode active substance, a conductive agent, a binder, a solvent and nano silica gel powder, wherein the nano silica gel powder comprises the following components in percentage by mass
Figure BDA0003470368740000071
It is understood that the mass percentage is
Figure BDA0003470368740000072
After being mixed with the positive active substance, the nano silica gel powder is matched with a conductive agent, so that the conductivity of the positive slurry is effectively improved, the lithium ion is favorably embedded and de-embedded, the charge and discharge multiplying power of the lithium battery is further improved, and the quick infiltration of the positive slurry is favorably realized; in addition, the mass percentage content is
Figure BDA0003470368740000073
The nanometer silica gel powder utilizes the higher porosity of the nanometer silica gel powder and the porosity of the positive active material to offset the thermal expansion of the nanometer silica gel powder, and can also play a supporting role for the positive slurry, reduce the collapse of the positive slurry when lithium ions are de-embedded, and further improve the cycle performance of the lithium battery.
In one embodiment, the conductive agent is at least one of carbon black, ketjen black, carbon fiber, and carbon nanotubes. It can be understood that carbon black, ketjen black, carbon fibers and carbon nanotubes can well form point, line and surface type lithium ion transmission and provide more binding sites for lithium ions, so that the lithium ion deintercalation and intercalation are facilitated, and the charge and discharge multiplying power of the lithium battery is further improved.
In one embodiment, the binder is at least one of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, styrene butadiene rubber, sodium carboxymethyl cellulose, nitrile butadiene rubber, and silica gel. It can be understood that at least one of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, styrene butadiene rubber, sodium carboxymethyl cellulose, nitrile rubber and silica gel is used as a binder of the positive electrode slurry, so that the adhesive strength of the positive electrode slurry on the positive electrode substrate is ensured.
In one embodiment, the solvent is N-methylpyrrolidone. It can be understood that the N-methyl pyrrolidone has better compatibility with the positive active material in the positive slurry, and is easy to be removed when the positive plate is dried, so as to better ensure the stability of the positive slurry.
In one embodiment, the positive active material is a nickel-cobalt-manganese ternary composite positive electrode material. It can be understood that the nickel-cobalt-manganese ternary composite positive electrode material and
Figure BDA0003470368740000081
the nanometer silica gel powder is matched, so that the positive electrode slurry has better electrolyte solution retention capacity, and better charge-discharge multiplying power and cycle performance.
In one embodiment, the positive active material is LiNi1/3Co1/3-x/3Mn1/3-x/3Mgx/3Vx/3O2-2yFyWherein x is more than 0 and less than or equal to 0.01, and y is more than 0 and less than or equal to 0.05. It is understood that the positive electrode active material is LiNi1/3Co1/3-x/3Mn1/3-x/3Mgx/3Vx/ 3O2-2yFyHas better stratum structure and electrochemical performance, and can be used in anode slurry
Figure BDA0003470368740000082
The nano silica gel powder is matched, so that the structural stability of the layered structure of the anode slurry coating layer on the surface of the anode substrate is well ensured in the lithium ion de-intercalation and intercalation processes, namely, the collapse of the anode slurry during the lithium ion de-intercalation process is reduced, the damage of the layered structure caused by the expansion of the anode slurry coating layer on the surface of the anode substrate is reduced, and the cycle performance, the charge and discharge multiplying power and the capacity retention rate of the lithium battery are further improved.
It can be understood that the nano silica gel powder is nano silica, and although the thermal expansion coefficient of the silica is lower than that of the silicon-based negative electrode material, the coating layer of the positive electrode slurry on the surface of the positive electrode substrate is thinner, even under the condition that the thermal expansion coefficient of the silica is lower, if the positive electrode slurry contains more silica, specifically, when the silicon content is more than 0.5 wt%, the positive electrode slurry still expands and contracts in the charging and discharging process of the lithium battery to affect the structural stability of the coating layer of the positive electrode slurry on the surface of the positive electrode substrate, so in the present application, in order to ensure the electrolyte solution retaining capability of the positive electrode slurry and ensure the wetting effect and the conductive performance of the positive electrode slurry, the scheme of using silica is retained, and the usage amount of silica is optimized from the overall formula of the positive electrode slurry, and particularly, it is found that, in the case of using a ternary composite positive electrode active material doped with magnesium and vanadium metal, the amount of silica used is made to be in the range of
Figure BDA0003470368740000091
During the process, the charging and discharging multiplying power of the lithium battery is well ensured, the rapid infiltration of the anode slurry is facilitated, the electrolyte solution retention capacity of the anode slurry is improved, the collapse of the anode slurry during the lithium ion deintercalation is reduced, and the cycle performance of the lithium battery is further improved.
In one embodiment, x is 0.01; y is 0.05. It can be understood that when the positive electrode active material LiNi1/ 3Co1/3-x/3Mn1/3-x/3Mgx/3Vx/3O2-2yFyWhen x is 0.01 and y is 0.05, the positive electrode active material has a stable layered structure and good electrochemical properties, and thus the cycle performance, charge and discharge rate and capacity retention rate of the lithium battery are better ensured.
In one embodiment, the method for preparing the positive active material includes the steps of:
putting lithium salt, nickel salt, cobalt salt, manganese salt, vanadium salt and organic acid into deionized water for mixing and dissolving operation to obtain a metal mixed solution;
heating the metal mixed solution to obtain metal sol;
calcining the metal sol;
and (4) crushing the calcined metal sol to obtain the positive active material.
According to the preparation method of the positive active material, the organic acid is adopted to dissolve the lithium salt, the nickel salt, the cobalt salt, the manganese salt and the vanadium salt, so that the lithium salt, the nickel salt, the cobalt salt, the manganese salt and the vanadium salt are fully mixed and dissolved, the mixing uniformity of the lithium salt, the nickel salt, the cobalt salt, the manganese salt and the vanadium salt is further ensured, the heating operation of the metal mixed solution is further ensured, the dispersion uniformity of all substances in the positive active material obtained after the calcination treatment is further ensured, the stability of the layered structure of the formed positive active material and the excellence of the electrochemical performance are further ensured, and the electrochemical performance and the cycle performance of the lithium battery are further improved.
In one embodiment, the method for preparing the positive active material includes the steps of:
putting lithium nitrate, nickel nitrate, cobalt nitrate, manganese nitrate, vanadium nitrate and citric acid into deionized water for mixing and dissolving to obtain a metal mixed solution;
heating the metal mixed solution to obtain metal sol;
calcining the metal sol;
and (4) crushing the calcined metal sol to obtain the positive active material.
According to the preparation method of the anode active substance, the nitric acid can form nitrogen dioxide and water after being heated and calcined, so that the anode slurry is prepared by adopting the lithium nitrate, the nickel nitrate, the cobalt nitrate, the manganese nitrate and the vanadium nitrate, the introduction of impurity ions is reduced, the formation stability of the layered structure of the anode active substance is ensured, the lithium nitrate, the nickel nitrate, the cobalt nitrate, the manganese nitrate and the vanadium nitrate are mixed and dissolved by utilizing the citric acid, the citric acid is a ternary acid, the mixing and dissolving of the lithium nitrate, the nickel nitrate, the cobalt nitrate, the manganese nitrate and the vanadium nitrate can be better promoted, the chelation of the lithium nitrate, the nickel nitrate, the cobalt nitrate, the manganese nitrate and the vanadium nitrate can be better promoted, namely the citric acid can form a chelate with a plurality of high-valence metal ions, the formation of the anode active substance with higher stability of the layered structure after being calcined is better realized, and the formed anode active substance is ensured to have better electrochemical performance, thereby ensuring the cycle performance and the electrochemical performance of the lithium battery.
In one embodiment, the pH of the metal mixed solution is 0.8 to 1.2. It can be understood that the PH of the metal mixed solution has a large influence on the electrochemical performance of the positive electrode active material, specifically, the cycle performance stability and the charge-discharge capacity retention rate of the lithium battery with the positive electrode active material, and under the condition of a high or low PH, it is difficult to ensure that the good cycle performance and the good capacity retention rate are maintained at the same time, so that in the application, the PH of the metal mixed solution is 0.8-1.2, and the lithium battery with the positive electrode active material has the good cycle performance stability and the good charge-discharge capacity retention rate at the same time.
In one embodiment, the pH value of the metal mixed solution is 1.0, so that the lithium battery with the positive active material is better ensured to have better cycle performance stability and charge-discharge capacity retention rate.
In one embodiment, the molar ratio of the sum of the nickel salt, cobalt salt, manganese salt and vanadium salt to the lithium salt is 1: (1.2-1.6). It can be understood that when the molar ratio of the sum of nickel salt, cobalt salt, manganese salt and vanadium salt to lithium salt is 5/6-5/8, the positive active material with better lithium ion de-intercalation and intercalation capabilities is formed, and the first discharge specific capacity and the cycle performance of the lithium battery are better ensured.
In one embodiment, the molar ratio of the sum of the nickel, cobalt, manganese and vanadium salts to the lithium salt is 1: 1.5. It can be understood that when the molar ratio of the sum of the nickel salt, the cobalt salt, the manganese salt and the vanadium salt to the lithium salt is 1:1.5, the formed positive active material is better ensured to have better lithium ion de-intercalation and intercalation capabilities, and further the first charge-discharge specific capacity and the cycle performance of the lithium battery are better ensured.
In one embodiment, the molar ratio of nickel salt, cobalt salt, manganese salt, and vanadium salt is 0.1:0.2:0.4: 0.2. It can be understood that when the molar ratio of the nickel salt, the cobalt salt, the manganese salt and the vanadium salt is 0.1:0.2:0.4:0.2, the specific discharge capacity of the positive electrode slurry reaches 200mAh/g, and the stable generation of the positive electrode active material with better layered structure and electrochemical performance is facilitated.
In one embodiment, the molar ratio of the sum of the nickel salt, the cobalt salt, the manganese salt, the vanadium salt and the lithium salt to the citric acid is 1.8-2.5. It can be understood that when the content of citric acid is high, the group in the citric acid interferes with the internal structure of the active material, so that the generated phenomenon that the layered structure of the positive active material is disordered and the internal group is aggregated is caused, namely the structure of the positive active material is in a disordered state, and the discharge specific capacity and the cycling stability of the lithium battery using the positive slurry are reduced, therefore, in the application, the molar ratio of the sum of nickel salt, cobalt salt, manganese salt, vanadium salt and lithium salt to the citric acid is 1.8-2.5, the stable and ordered layered structure of the positive active material is well ensured, and the discharge specific capacity and the cycling stability of the lithium battery containing the positive slurry are further ensured.
In one embodiment, the molar ratio of the sum of the nickel, cobalt, manganese, vanadium and lithium salts to citric acid is 2. It can be understood that the molar ratio of the sum of the nickel salt, the cobalt salt, the manganese salt, the vanadium salt and the lithium salt to the citric acid is 2, so that the stable and ordered structure of the layered structure of the positive active material is better ensured, and the discharge specific capacity and the cycling stability of the lithium battery containing the positive slurry are further ensured.
In one embodiment, the temperature at which the metal mixed solution is heated is 80 to 90 ℃. It can be understood that the heating operation of the metal mixed solution is performed to reduce the content of the solvent in the metal mixed solution, which is advantageous for the calcination of the metal mixed solution, and the heating of the metal mixed solution at 80 to 90 ℃ is advantageous for the order and stability of the layered structure of the cathode active material formed after the calcination.
In one embodiment, the metal sol is calcined, which specifically includes the following steps: pre-calcining the metal sol;
carrying out secondary calcination treatment on the metal sol subjected to the pre-calcination treatment;
and carrying out tertiary calcination treatment on the metal sol subjected to the secondary calcination treatment.
The metal sol is calcined, citric acid and vanadium nitrate are contained in the metal sol, namely, the metal sol has a carbon source, when the vanadium nitrate is calcined, the high-valence oxide of vanadium can be sublimated and consumed at a lower temperature, and then a three-stage calcination mode is needed, so that the oxidation valence of vanadium is lower at the lower temperature, and then the temperature is increased to continue calcining, and the stable generation of the vanadium-doped ternary composite material is promoted.
In one embodiment, the metal sol is pre-calcined at 400-500 deg.c for 2-3 hr. It can be understood that the calcination is carried out for 2 to 3 hours at the temperature of between 400 and 500 ℃, so that the rapid removal of the solvent is effectively ensured, and the stability of each substance in the metal sol is ensured.
In one embodiment, the temperature for carrying out the secondary calcination treatment on the metal sol subjected to the pre-calcination treatment is 600-700 ℃ and the time is 3-5 hours. It can be understood that the calcination is continued for 3 to 5 hours at the temperature of between 600 and 700 ℃, so that the reduction of the valence of the high-valence oxide of the vanadium is effectively ensured, and the stable generation of the vanadium-doped ternary composite material is effectively ensured.
In one embodiment, the temperature for carrying out the three-time calcination treatment on the metal sol subjected to the secondary calcination treatment is 800-1350 ℃ and the time is 6-8 h. It can be understood that the calcination is continuously carried out for 6 to 8 hours at the temperature of between 800 and 1350 ℃, so that the stable generation of the positive active material with better layered structure and electrochemical performance is effectively ensured.
The application also provides a preparation method of the battery cell, which is used for preparing the battery cell of any embodiment. The preparation method of the battery cell comprises the following steps: obtaining a copper foil piece to be processed, a diaphragm and a positive plate; cutting the copper foil to be processed to integrally form the negative electrode lug and the auxiliary electrode lug on the copper foil to obtain a negative electrode sheet; carrying out lamination connection operation on the diaphragm, the plurality of negative plates and the plurality of positive plates so that copper foils of the plurality of negative plates and the plurality of positive plates are alternately laminated one by one, and the diaphragm is arranged between each positive plate and the copper foil of the adjacent negative plate to obtain a semi-finished product of the battery core; and carrying out tab connection operation on the semi-finished product of the battery cell to obtain the battery cell.
According to the preparation method of the battery core, based on the copper foil to be processed, the structure of the negative plate is adjusted, namely the copper foil to be processed is cut, so that the negative electrode lug and the auxiliary electrode lug are integrally formed on the copper foil, the connection stability of the negative electrode lug and the auxiliary electrode lug and the copper foil is ensured, and the arrangement of the auxiliary electrode lug ensures that the copper foil of the negative plate is still connected with the whole negative plate assembly, so that the problem that the copper foil of a part of negative plates is oxidized due to the fact that the copper foil is in high potential after the negative electrode lug of the part of negative plates is broken, the copper foil is oxidized, and further the internal short circuit of the battery is caused, so that the thermal runaway of the battery core is caused, is effectively reduced, and the use safety of the battery core containing the negative plate assembly is effectively improved; in addition, before the negative electrode tab and the auxiliary electrode tab of the negative electrode piece are connected in a laminated manner, the negative electrode piece, the diaphragm and the positive electrode piece are sequentially and alternately arranged in a laminated manner, so that the alternate laminating speed of the negative electrode piece, the diaphragm and the positive electrode piece is favorably improved, and the preparation efficiency of the battery cell is further improved.
Referring to fig. 6, in order to better understand the method for manufacturing the battery cell of the present application, the method for manufacturing the battery cell of the present application is further explained below, and the method for manufacturing the battery cell of an embodiment includes the following steps:
s100, obtaining a copper foil sheet to be processed, a diaphragm and a positive plate. It can be understood, because the temperature rise of utmost point ear position is the most serious, and in the preparation process of lithium cell, utmost point ear receives outside interference easily and takes place cracked problem, if some utmost point ear breaks off, especially under the negative pole ear fracture condition, then the inside negative pole piece of lithium cell can take place sharp redox reaction and cause the temperature to rise fast, the thermal runaway problem of lithium cell has further aggravated, there is great safety hazard in utilization, therefore, based on waiting to process the copper foil piece, adjust negative pole piece structure, and then realize lightening the thermal runaway of lithium cell.
S200, cutting the copper foil to be processed to enable the negative electrode lug and the auxiliary electrode lug to be integrally formed on the copper foil to obtain the negative electrode piece. It can be understood, treat the processing copper foil piece and cut the operation, make negative pole ear and supplementary utmost point ear integrated into one piece on the copper foil piece, the connection stability of negative pole ear and supplementary utmost point ear and copper foil piece has been ensured, and the setting of assisting utmost point ear, make the copper foil piece of this negative pole piece still link together in whole negative pole piece subassembly, the copper foil piece of having avoided partial negative pole piece is in the high potential and takes place the oxidation, the copper foil piece that corresponds after having avoided the negative pole ear of partial negative pole piece to take place to fracture promptly is in the high potential, cause this copper foil piece by oxidation, and then arouse the inside short circuit of battery and lead to electric core thermal runaway problem, the thermal runaway of the electric core that contains this negative pole piece subassembly has been alleviateed effectively, and then the safety in utilization of the electric core that contains this negative pole piece subassembly has been improved effectively.
S300, carrying out stacking connection operation on the diaphragm, the negative plates and the positive plates so that the copper foils of the negative plates and the positive plates are alternately stacked in a one-to-one correspondence manner, and the diaphragm is arranged between each positive plate and the copper foil of the adjacent negative plate to obtain a semi-finished product of the battery cell. It can be understood that before the negative electrode tab and the auxiliary electrode tab of the negative electrode tab are connected in a laminated manner, the negative electrode tab, the diaphragm and the positive electrode tab are sequentially and alternately arranged in a laminated manner, so that the alternate laminating speed of the negative electrode tab, the diaphragm and the positive electrode tab is improved, and the preparation efficiency of the battery cell is improved.
And S400, carrying out tab connection operation on the semi-finished product of the battery cell to obtain the battery cell. It can be understood that, carry out utmost point ear connection operation to electric core semi-manufactured goods, carry out range upon range of connection for the anodal ear to the positive plate in the electric core promptly, carry out range upon range of connection to the negative pole ear of the negative plate in the electric core, and carry out range upon range of connection to the auxiliary pole ear of the negative plate in the electric core, realized the preparation of electric core, and after stacking up negative plate, diaphragm and positive plate in proper order in turn, carry out utmost point ear connection operation to electric core semi-manufactured goods again, be favorable to improving the preparation efficiency of electric core.
According to the preparation method of the battery core, based on the copper foil to be processed, the structure of the negative plate is adjusted, namely the copper foil to be processed is cut, so that the negative electrode lug and the auxiliary electrode lug are integrally formed on the copper foil, the connection stability of the negative electrode lug and the auxiliary electrode lug and the copper foil is ensured, and the arrangement of the auxiliary electrode lug ensures that the copper foil of the negative plate is still connected with the whole negative plate assembly, so that the problem that the copper foil of a part of negative plates is oxidized due to the fact that the copper foil is in high potential after the negative electrode lug of the part of negative plates is broken, the copper foil is oxidized, and further the internal short circuit of the battery is caused, so that the thermal runaway of the battery core is caused, is effectively reduced, and the use safety of the battery core containing the negative plate assembly is effectively improved; in addition, before the negative electrode tab and the auxiliary electrode tab of the negative electrode piece are connected in a laminated manner, the negative electrode piece, the diaphragm and the positive electrode piece are sequentially and alternately arranged in a laminated manner, so that the alternate laminating speed of the negative electrode piece, the diaphragm and the positive electrode piece is favorably improved, and the preparation efficiency of the battery cell is further improved.
In one embodiment, before the step of cutting the copper foil to be processed, the method for preparing the battery cell further includes the following steps: and carrying out preheating treatment on the copper foil to be processed so as to soften the copper foil to be processed. It can be understood that when the copper foil to be processed is cut, that is, when the copper foil to be processed is cut by using the die cutter, a burr appears at the cut part of the copper foil obtained after cutting, and the existence of the burr makes the negative electrode plate easily pierce the diaphragm, so that a micro short circuit occurs inside the electric core, and further aggravates the thermal runaway problem of the electric core, therefore, in order to alleviate the situation that the negative electrode plate pierces the diaphragm, and further aggravates the thermal runaway inside the electric core, in the application, before the step of cutting operation, the copper foil to be processed is preheated, the copper foil to be processed after preheating is softened, the hardness of the softened copper foil to be processed is lower, so that when the copper foil to be processed with lower hardness is cut, the burr amount at the cut part of the copper foil to be processed is greatly reduced, the burr of the negative electrode plate is effectively alleviated, and further aggravated the thermal runaway inside the electric core when the negative electrode plate pierces the diaphragm is alleviated, the use safety of the battery cell containing the negative plate component is effectively improved.
In one embodiment, the pre-heat treatment temperature of the copper foil to be processed is 400 ℃ to 550 ℃. It can be understood that, under the condition that the temperature is 400 ℃ -550 ℃, the preheating treatment is carried out on the copper foil to be processed, the softening of the copper foil to be processed is effectively ensured, and further, when the copper foil to be processed with lower hardness is cut, the burr quantity of the cutting part of the copper foil to be processed is greatly reduced, the flash of the negative electrode plate is effectively reduced, the situation that the negative electrode plate pierces through the diaphragm to further aggravate the thermal runaway in the battery core is further reduced, and the use safety of the battery core containing the negative electrode plate assembly is effectively improved.
In one embodiment, the temperature for preheating the copper foil to be processed is 500 ℃, the softening degree of the copper foil to be processed is better controlled, so that when the copper foil to be processed with lower hardness is cut, the burr quantity of the cut part of the copper foil to be processed is better reduced, the flash of the negative electrode plate is effectively reduced, the situation that the negative electrode plate pierces through a diaphragm to further aggravate thermal runaway in the battery core is further reduced, and the use safety of the battery core containing the negative electrode plate assembly is effectively improved.
In one embodiment, the cutting operation performed on the copper foil to be processed is specifically as follows: and fixing the copper foil piece to be processed, and integrally punching and molding the fixed copper foil piece to be processed by adopting a punching machine to obtain the negative plate. The method can be understood that the copper foil piece to be processed is cut after being fixed, so that the forming consistency of the negative pole piece is effectively ensured, and the quality of the battery cell is further ensured.
In one embodiment, before the step of obtaining the negative electrode sheet and after the step of performing a cutting operation on the copper foil to be processed, the method for preparing the battery cell further includes the following steps:
splicing the copper foil to be processed after the cutting operation;
reinforcing the spliced copper foil piece to be processed;
and carrying out negative electrode slurry coating treatment on the reinforced copper foil to be processed.
In the preparation method of the battery core, the copper foil pieces to be processed after cutting operation are spliced, namely the negative electrode pieces and the residual copper foil pieces of the copper foil pieces to be processed are spliced, and then the spliced copper foil pieces to be processed are reinforced, namely the spliced negative electrode pieces and the residual copper foil pieces of the copper foil pieces to be processed are fixed, so that the subsequent negative electrode pieces are favorably uniformly and quickly coated with negative electrode slurry, namely the reinforced copper foil pieces to be processed are coated with the negative electrode slurry, and simultaneous coating of a plurality of negative electrode pieces can be realized, the preparation efficiency of the negative electrode pieces is effectively increased, the consistency of the negative electrode pieces is ensured, and the quality of the battery core is improved.
In one embodiment, after the step of performing the negative electrode slurry coating treatment on the reinforced copper foil to be processed and before the step of obtaining the negative electrode sheet, the method for preparing the battery core further includes the following steps: and carrying out drying and rolling treatment on the copper foil to be processed after the negative electrode slurry is coated. It can be understood that the negative pole pieces coated with the negative pole slurry are dried and rolled, namely, the negative pole slurry is dried and rolled, and a plurality of negative pole pieces are uniformly dried and rolled, so that the consistency of the negative pole pieces is effectively improved, and the quality of the battery cell is improved.
The present application further provides a laminated battery. The laminated battery comprises the battery cell of any one of the embodiments, and further comprises electrolyte and a shell, wherein the electrolyte is filled in the shell, the battery cell is arranged in the shell, and the battery cell is soaked in the electrolyte.
The laminated battery adopts the battery core, so that the electrolyte is filled in the shell, the battery core is arranged in the shell, and the battery core is soaked in the electrolyte, thereby effectively lightening the thermal runaway of the battery and further effectively improving the use safety of the battery.
Compared with the prior art, the invention has at least the following advantages:
according to the negative plate assembly, the negative electrode tabs and the corresponding auxiliary electrode tabs are connected with the corresponding copper foils, the negative electrode tabs of the negative electrode plates are connected in a stacked mode, the auxiliary electrode tabs of the negative electrode plates are connected in a stacked mode, and when partial negative electrode tabs of the negative electrode plates are broken, the copper foils of the negative electrode plates are still connected with the whole negative plate assembly due to the existence of the auxiliary electrode tabs on the negative electrode plates, so that the problem that the copper foils of partial negative electrode plates are oxidized due to the fact that the copper foils are in high potential, namely, the problem that the copper foils are oxidized due to the fact that the corresponding copper foils are in high potential after the negative electrode tabs of partial negative electrode plates are broken, and further the problem that the internal short circuit of a battery cell is caused to cause thermal runaway is solved, the thermal runaway of the battery cell containing the negative electrode plate assembly is effectively relieved, and the use safety of the battery cell containing the negative electrode plate assembly is effectively improved.
The following examples are given by way of illustration, and it is noted that the following examples are not intended to be exhaustive of all possible and that the materials used in the following examples are commercially available without specific recitation.
Example 1
Under the condition that the temperature is 400 ℃, carrying out preheating treatment on copper foil to soften the copper foil, cutting the softened copper foil to obtain a negative electrode tab and an auxiliary electrode tab which are integrally formed on the negative electrode sheet of the copper foil, splicing and fixing the cut negative electrode sheet, coating negative electrode slurry on the spliced and fixed negative electrode sheet, rolling and drying, then laminating a diaphragm, a plurality of obtained negative electrode sheets and a plurality of positive electrode sheets one by one alternately to enable the positive electrode sheets and the negative electrode sheets to be isolated by the diaphragm, welding the positive electrode tabs of the positive electrode sheets, respectively welding the negative electrode tabs and the auxiliary electrode tabs of the negative electrode sheets to obtain an electric core, and carrying out formation treatment on the electric core.
Example 2
Under the condition that the temperature is 500 ℃, carrying out preheating treatment on copper foil to soften the copper foil, cutting the softened copper foil to obtain a negative electrode tab and an auxiliary electrode tab which are integrally formed on the negative electrode sheet of the copper foil, splicing and fixing the cut negative electrode sheet, coating negative electrode slurry on the spliced and fixed negative electrode sheet, rolling and drying, then laminating a diaphragm, a plurality of obtained negative electrode sheets and a plurality of positive electrode sheets one by one alternately to enable the positive electrode sheets and the negative electrode sheets to be isolated by the diaphragm, welding the positive electrode tabs of the positive electrode sheets, respectively welding the negative electrode tabs and the auxiliary electrode tabs of the negative electrode sheets to obtain an electric core, and carrying out formation treatment on the electric core.
Example 3
The method comprises the steps of preheating copper foil at 550 ℃, softening the copper foil, cutting the softened copper foil to obtain a negative electrode tab and an auxiliary electrode tab which are integrally formed on the copper foil, splicing and fixing the cut negative electrode tab, coating negative electrode slurry on the spliced and fixed negative electrode tab, rolling and drying, stacking a diaphragm, a plurality of obtained negative electrode tabs and a plurality of positive electrode tabs one by one in an alternating mode, isolating the positive electrode tab from the negative electrode tab by the diaphragm, welding the positive electrode tab of the positive electrode tab, welding the negative electrode tab and the auxiliary electrode tab of the negative electrode tab respectively, assembling to obtain an electric core, and carrying out formation treatment on the electric core.
The short circuit detection is performed on the battery cells obtained in the embodiments 1 to 3, 1000 of the battery cells prepared in the embodiments 1 to 3 are respectively detected, and specifically, the detection is performed after the battery cells in the embodiments 1 to 3 are subjected to 100 times of constant current charging and discharging.
Table 1: short circuit detection pass rate of battery cells in embodiments 1-3
Example 1 Example 2 Example 3
Passage Rate (%) 99.90 99.98 99.92
After 100 constant current charge and discharge to electric core, the short circuit that the utmost point ear fracture formed takes place inside the electric core, or the short circuit that the diaphragm puncture formed, or other short circuit condition homoenergetic also can exist, and can see from table 1, the short circuit detection through rate of electric core after constant current charge and discharge many times that embodiment 1 ~ 3 prepare is higher, has all exceeded 99.90%, and the probability that the electric core that the explanation made exists the condition of above internal short circuit is lower, and then shows that the thermal runaway hidden danger of the electric core that this application made is less.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. The utility model provides a negative pole piece subassembly, its characterized in that includes a plurality of negative pole pieces, each the negative pole piece includes copper foil, negative pole ear and assists the utmost point ear, the negative pole ear with correspond assist utmost point ear all with correspond copper foil connection is a plurality of the negative pole piece the negative pole ear is range upon range of to be connected, and is a plurality of the negative pole piece assist utmost point ear range upon range of to be connected.
2. The negative electrode tab assembly of claim 1, wherein the negative electrode tabs of a plurality of the negative electrode tabs are stack-welded together.
3. A negative electrode tab assembly according to claim 1, wherein the auxiliary electrode tabs of a plurality of the negative electrode tabs are stack-welded together.
4. The negative plate assembly of claim 1, further comprising a plurality of nickel layers, wherein the plurality of nickel layers are connected with the negative tabs of the plurality of negative plates in a one-to-one correspondence, and each nickel layer is wound on the negative tab of the corresponding negative plate.
5. The negative plate assembly of claim 1, wherein the negative tab and the auxiliary tab are disposed on the same side of the copper foil.
6. The negative electrode tab assembly of claim 1, wherein the negative electrode tabs are disposed opposite the auxiliary electrode tabs on both sides of the copper foil.
7. An electric core, comprising the negative electrode plate assembly of any one of claims 1 to 6, further comprising a separator and a plurality of positive electrode plates, wherein the copper foil sheets of the negative electrode plates and the positive electrode plates are alternately stacked in a one-to-one correspondence manner, and the separator is disposed between each positive electrode plate and the copper foil sheet of the adjacent negative electrode plate.
8. The battery cell of claim 7, wherein each positive electrode plate comprises an aluminum foil and a positive electrode tab, the positive electrode tabs of the positive electrode plates are connected in a stacked manner, the aluminum foils of the positive electrode plates and the copper foils of the negative electrode plates are alternately stacked in a one-to-one correspondence manner, and the separator is disposed between the aluminum foil of each positive electrode plate and the copper foil of the adjacent negative electrode plate.
9. A method for preparing a cell, for preparing the cell of claim 7 or 8, the method comprising the steps of:
obtaining a copper foil piece to be processed, a diaphragm and a positive plate;
cutting the copper foil to be processed to integrally form the negative electrode lug and the auxiliary electrode lug on the copper foil to obtain a negative electrode sheet;
carrying out stacking connection operation on the diaphragm, the plurality of negative plates and the plurality of positive plates so that the copper foils of the plurality of negative plates and the plurality of positive plates are alternately stacked in a one-to-one correspondence manner, and the diaphragm is arranged between each positive plate and the copper foil of the adjacent negative plate to obtain a semi-finished product of the battery core;
and carrying out tab connection operation on the semi-finished product of the battery cell to obtain the battery cell.
10. A laminated battery, comprising the battery cell of claim 7 or 8, and further comprising an electrolyte and a casing, wherein the electrolyte is filled in the casing, the battery cell is disposed in the casing, and the battery cell is soaked in the electrolyte.
CN202210041387.XA 2022-01-14 2022-01-14 Negative plate component, battery core, preparation method of battery core and laminated battery Pending CN114242944A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114927834A (en) * 2022-07-01 2022-08-19 齐鲁中科光物理与工程技术研究院 Battery pole piece, electrode core and secondary battery
CN115189100A (en) * 2022-09-06 2022-10-14 宁德新能源科技有限公司 Electrode assembly, electrochemical device, and electric device
CN116598561A (en) * 2023-05-09 2023-08-15 深圳欣视界科技有限公司 Packaging method of laminated battery cell and laminated battery

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114927834A (en) * 2022-07-01 2022-08-19 齐鲁中科光物理与工程技术研究院 Battery pole piece, electrode core and secondary battery
CN114927834B (en) * 2022-07-01 2024-01-09 齐鲁中科光物理与工程技术研究院 Battery pole piece, electrode core and secondary battery
CN115189100A (en) * 2022-09-06 2022-10-14 宁德新能源科技有限公司 Electrode assembly, electrochemical device, and electric device
CN115189100B (en) * 2022-09-06 2023-08-22 宁德新能源科技有限公司 Electrode assembly, electrochemical device and electric equipment
CN116598561A (en) * 2023-05-09 2023-08-15 深圳欣视界科技有限公司 Packaging method of laminated battery cell and laminated battery
CN116598561B (en) * 2023-05-09 2024-04-16 深圳欣界能源科技有限公司 Packaging method of laminated battery cell and laminated battery

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