CN114975856A - Electrode plate, battery and battery preparation method - Google Patents

Electrode plate, battery and battery preparation method Download PDF

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Publication number
CN114975856A
CN114975856A CN202210690684.7A CN202210690684A CN114975856A CN 114975856 A CN114975856 A CN 114975856A CN 202210690684 A CN202210690684 A CN 202210690684A CN 114975856 A CN114975856 A CN 114975856A
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battery
pole piece
isolation layer
lithium
electrode sheet
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CN114975856B (en
Inventor
李彦
张双虎
田生
吕远轰
朱攀
王腾云
钟泽
谢继春
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Zhuhai Cosmx Battery Co Ltd
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Zhuhai Cosmx Battery Co Ltd
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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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • 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
    • H01M4/139—Processes of manufacture
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • 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 Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Composite Materials (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

The invention provides an electrode plate, a battery and a battery preparation method. Through the isolation effect of the isolation layer, electrode plates with different polarities can be directly laminated or wound to form an electric core in the preparation process of the battery, the battery structure is simplified, the process of setting the diaphragm is reduced, the situation that the diaphragm is misplaced or falls off is avoided, the internal short circuit of the battery is caused, the safety of the battery is improved, the setting of the diaphragm is cancelled in the battery, the spacing distance between the electrode plates is optimized, the occupation ratio of active substances in the electrode plates is increased under the condition that the thickness of the battery is unchanged, and the energy density of the battery is improved.

Description

Electrode plate, battery and battery preparation method
Technical Field
The invention relates to the technical field of batteries, in particular to an electrode plate, a battery and a battery preparation method.
Background
Lithium batteries are widely used in the fields of consumer electronics, new energy automobiles and the like. With the progress of technology, the demand for energy density of lithium ion batteries is also increasing.
At present, a battery mainly comprises a positive plate, a negative plate, a diaphragm and electrolyte, in the preparation process of the battery, a current collector is dried, rolled, cut and welded with a tab to prepare the positive plate or the negative plate, then the diaphragm is prepared by polyethylene, polypropylene and other materials and arranged between the positive plate and the negative plate to prevent electrons from passing through so as to prevent the short circuit between the positive plate and the negative plate, and then the diaphragm is wound to form a battery core. The battery has a complex structure and more preparation processes, and the situation that the positive plate and the negative plate are in direct contact due to the slippage of the diaphragm easily occurs, so that the internal short circuit of the battery is caused, and the safety of the battery is influenced.
Therefore, the prior art has the problem of low battery safety.
Disclosure of Invention
The embodiment of the invention provides an electrode plate, a battery and a battery preparation method, and aims to solve the problem of low battery safety in the prior art.
The embodiment of the invention provides an electrode plate which comprises a current collector and an isolating layer, wherein the current collector comprises a first surface and a second surface, the isolating layer is arranged on at least one of the first surface and the second surface, and the isolating layer comprises hexagonal boron nitride.
Optionally, the composition of the separator layer comprises a lithium salt.
Optionally, the composition of the barrier layer comprises a ductile material.
Optionally, the components of the isolation layer include hexagonal boron nitride, a ductile material, an adhesive, and a lithium salt, and a ratio of the hexagonal boron nitride to the ductile material to the adhesive to the lithium salt is in a range of, by mass: 30 to 60 wt%, 1 to 10 wt%.
Optionally, the current collector further comprises an active layer, the active layer is disposed between the current collector and the isolation layer, and a projection of the isolation layer on the current collector is larger than a projection of the active layer on the current collector.
Optionally, the thickness of the isolation layer is 3 to 25 microns.
Optionally, the separator layer has a porosity of 25% to 50%.
Optionally, the tough material comprises at least one of graphene oxide, a two-dimensional material, polyethylene oxide, polyester resin, fiber paper, non-woven fabric and nanocellulose; and/or the presence of a gas in the atmosphere,
the adhesive comprises at least one of polyvinyl alcohol, acrylonitrile, acrylic acid, styrene butadiene rubber, carboxymethyl cellulose, polyvinylidene fluoride, polyvinylpyrrolidone and polyimide; and/or the presence of a gas in the gas,
the lithium salt includes at least one of lithium perchlorate, lithium chloride, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium tetrafluoroborate and lithium bis fluorosulfonylimide.
The embodiment of the invention also provides a battery, which comprises a first pole piece, a second pole piece and electrolyte, wherein at least one of the first pole piece and the second pole piece is the above electrode piece.
The embodiment of the invention also provides a battery preparation method, which comprises the following steps:
preparing a first pole piece and a second pole piece, wherein at least one of the first pole piece and the second pole piece comprises an isolation layer, and the isolation layer comprises hexagonal boron nitride;
winding or laminating the first pole piece and the second pole piece to form a battery core;
and placing the battery core in an aluminum-plastic film, and injecting electrolyte to form the battery.
In the embodiment of the invention, the isolating layer is arranged on at least one of the first surface and the second surface of the current collector, which are opposite to each other, the components of the isolating layer comprise hexagonal boron nitride, and the electrode plates with different polarities can be directly laminated or wound to form a battery cell in the preparation process of the battery through the isolating function of the isolating layer, so that the battery structure is simplified, the process of arranging the diaphragm is reduced, the internal short circuit of the battery caused by the conditions of dislocation, falling off and the like of the diaphragm is avoided, and the safety of the battery is improved.
In addition, the battery manufactured by the electrode plates provided by the invention has the advantages that the arrangement of the diaphragm is omitted, the spacing distance between the electrode plates is optimized, the proportion of active substances in the electrode plates is increased under the condition that the thickness of the battery is not changed, and the energy density of the battery is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.
Fig. 1 is a schematic structural diagram of an electrode sheet provided in an embodiment of the present invention;
fig. 2 is a schematic flow chart of a battery manufacturing method according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious 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.
The terms first, second and the like in the description and in the claims of the present invention are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the structures so used are interchangeable under appropriate circumstances such that embodiments of the invention may be practiced in sequences other than those illustrated or described herein, and that the terms "first", "second", etc. are generally used herein as a class and do not limit the number of terms, for example, a first term can be one or more than one. In addition, "and/or" in the specification and claims means at least one of connected objects, a character "/" generally means that a preceding and succeeding related objects are in an "or" relationship.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an electrode sheet according to an embodiment of the present invention, and as shown in fig. 1, an embodiment of the present invention provides an electrode sheet including a current collector 101 and an isolation layer 103, where the current collector 101 includes a first surface and a second surface, the isolation layer 103 is disposed on at least one of the first surface and the second surface, and a composition of the isolation layer 103 includes hexagonal boron nitride.
In this embodiment, the isolation layer 103 is disposed on at least one of the first and second surfaces of the current collector 101 opposite to each other, and the composition of the isolation layer 103 includesHexagonal boron nitride, which is a good thermal conductor, an electrical insulator and has good mechanical properties, can conduct lithium ions, and has an insulator so that electrons cannot pass through the insulator and can freely pass through the insulator, thereby preventing the short circuit of the positive electrode and the negative electrode; wherein the hexagonal boron nitride has particle size of 0.5-1 μm, purity of 99%, and specific surface area of 9m 2 G to 16m 2 A density of 2.25g/cm 3 。
Like this, through the isolation of isolation layer 103 for electrode slice direct lamination or the coiling of different polarity form electric core in the preparation of battery, simplified battery structure, reduced the process that sets up the diaphragm, avoid the diaphragm to appear the dislocation, the condition such as drop leads to the inside short circuit of battery, thereby improved the security of battery.
In addition, the battery manufactured by the electrode plates provided by the invention has the advantages that the arrangement of the diaphragm is omitted, the spacing distance between the electrode plates is optimized, the proportion of active substances in the electrode plates is increased under the condition that the thickness of the battery is not changed, and the energy density of the battery is improved.
When the electrode sheet is wound or a multi-electrode-sheet lamination is arranged, the isolating layers 103 can be arranged on the first surface and the second surface of the current collector 101 opposite to each other, so that the short circuit between adjacent electrode sheets after winding or lamination is reduced.
Alternatively, the isolation layer 103 may be disposed on any one of the first surface and the second surface, and the electrode sheet improved in the present invention may be disposed opposite to the other electrode sheet through the isolation layer 103, so that electrons cannot pass through, but electrons can freely pass through, so as to prevent the positive and negative electrodes from being short-circuited.
Optionally, the composition of the isolation layer 103 includes a lithium salt.
In this embodiment, lithium salt is added to the isolation layer 103 to improve lithium ion conduction in the electrode sheet and improve the first coulombic efficiency of the battery.
The lithium salt can include at least one of lithium perchlorate, lithium chloride, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium tetrafluoroborate and lithium bis-fluorosulfonyl imide, and can be adjusted according to actual use requirements.
Optionally, the composition of the isolation layer 103 includes a ductile material.
In this embodiment, can coil the setting with the electrode slice to form roll core, through add toughness material in isolation layer 103, with the pliability that improves isolation layer 103, thereby be convenient for the electrode slice to coil and cut, form roll core.
The tough material may include at least one of graphene oxide, a two-dimensional material (MXene), polyethylene oxide PEO, polyester resin PET, fiber paper, non-woven fabric, and nanocellulose, and may be adjusted according to actual use requirements.
Optionally, the active layer 102 is further included, the active layer is disposed between the current collector 101 and the isolation layer 103, and a projection of the isolation layer 103 on the current collector 101 is larger than a projection of the active layer 102 on the current collector 101.
In this embodiment, the active layer 102 is coated on the first surface and the second surface of the current collector 101 opposite to each other, the isolation layer 103 covers the active layer 102, and the projection of the isolation layer 103 on the current collector 101 is greater than the projection of the active layer 102 on the current collector 101, so that the isolation effect of the isolation layer 103 is enhanced, the direct contact between the current collector 101 and the different polar materials on the surfaces of the two sides of the current collector 101 is reduced, and the safety of the battery is improved.
Specifically, an active layer slurry may be prepared, and the active layer slurry is coated on the surface of the current collector 101 to form the active layer 102; then, a separator slurry is prepared, and the separator slurry is coated on the active layer 102 to form the separator 103. And the isolation layer 103 completely covers the active layer 102, so that the head, the tail and the width of the pole piece are respectively more than 0.5mm, the internal short circuit of the battery is prevented, and the safety of the battery is improved.
Alternatively, the thickness of the isolation layer 103 may be 3 to 25 micrometers.
In this embodiment, the isolation layer 103 may be formed by gravure coating or spray coating, the isolation layer 103 covers the active layer 102, and the thickness of one side of the isolation layer 103 may be 3 to 25 micrometers. The thickness of the separator 103 may be adaptively adjusted according to the type and design requirements of the battery, for example, the thickness of one side of the separator 103 may be 3 μm, 5 μm, 7 μm, 9 μm, 12 μm, 15 μm, 17 μm, 20 μm, 22 μm or 25 μm.
Preferably, the thickness of the isolation layer 103 may be 3 to 7 micrometers, and the proportion of the active layer 102 in the electrode tab is increased under the condition that the thickness of the battery is not changed, so that the energy density of the battery is improved.
The porosity of the isolation layer 103 may be 25% to 50%, and preferably, the porosity may be 30% to 45%, so as to increase the mobility rate of lithium ions, thereby increasing the conductivity of the battery.
Optionally, the components of the isolation layer 103 include hexagonal boron nitride, a tough material, an adhesive, and a lithium salt, and the ratio of the hexagonal boron nitride, the tough material, the adhesive, and the lithium salt in percentage by mass may be: 30 to 60 wt%, 1 to 10 wt%.
In this embodiment, the hexagonal boron nitride, the ductile material, the adhesive and the lithium salt are prepared into a first slurry according to the mass percentage ratio of (30-60 wt%) (1-10 wt%), then a solvent is added and stirred to prepare a second slurry, and the second slurry is coated on the active layer 102 to form the isolation layer 103. Wherein the ratio of the hexagonal boron nitride, the ductile material, the binder, and the lithium salt in the second slurry may be 40% to 60%, in other words, the solid content of the second slurry may be 40% to 60%.
For example, the mass percentage of the hexagonal boron nitride may be 50%, the mass percentage of the tough material may be 44%, the mass percentage of the adhesive may be 5%, and the mass percentage of the lithium salt may be 1%, the hexagonal boron nitride, the tough material, the adhesive and the lithium salt are prepared into a first slurry, and then the first slurry is added with a solvent and stirred to prepare a second slurry, and the solid content in the second slurry may be 60%.
Therefore, the migration rate of lithium ions is improved, and the conductivity of the battery is enhanced; meanwhile, the isolation effect of the isolation layer 103 is enhanced, so that electrode plates with different polarities can be directly laminated or wound to form a battery core in the preparation process of the battery, the structure of the battery is simplified, the process of arranging the diaphragm is reduced, the internal short circuit of the battery caused by the conditions of dislocation, falling and the like of the diaphragm is avoided, and the safety of the battery is improved.
The adhesive comprises at least one of polyvinyl alcohol, acrylonitrile, acrylic acid, styrene butadiene rubber, carboxymethyl cellulose, polyvinylidene fluoride, polyvinylpyrrolidone and polyimide;
the solvent comprises at least one of N-methyl pyrrolidone, N-dimethylformamide, acetone, N-heptane, toluene, 1, 4-dioxane and ethyl lactate; n-methylpyrrolidone, N, N-dimethylformamide is preferred.
Referring to fig. 2, fig. 2 is a schematic flow chart of a battery manufacturing method according to an embodiment of the present invention, and as shown in fig. 2, the method includes the following steps:
step 1, preparing a first pole piece and a second pole piece, wherein at least one of the first pole piece and the second pole piece comprises an isolation layer, and the isolation layer comprises hexagonal boron nitride;
in this step, the first and second pole pieces correspond to electrode pieces with different polarities, for example, the first pole piece may be a negative pole piece, and the second pole piece may be a positive pole piece. Configuring a negative electrode active material into a negative electrode active layer, and laying the negative electrode active layer on the surface of a negative electrode current collector; meanwhile, preparing the positive electrode active substance into a positive electrode active layer, and laying the positive electrode active layer on the surface of a positive electrode current collector; then, a spacer 103 is formed by disposing a spacer material including hexagonal boron nitride and the like, and the spacer 103 is disposed on the negative electrode active layer and/or the positive electrode active layer to obtain a first pole piece and a second pole piece.
Then, winding or laminating the first pole piece and the second pole piece to form a battery cell in the step 2; and step 3, placing the battery core in an aluminum-plastic film, baking to remove water, injecting electrolyte, and carrying out processes such as formation, aging and the like to form the battery.
In the embodiment, through the isolation effect of the isolation layer 103, electrode plates with different polarities can be directly laminated or wound to form a battery core in the preparation process of the battery, the structure of the battery is simplified, the processes of preparing and setting the diaphragm are reduced, the situation that the diaphragm is dislocated, falls off and the like to cause short circuit inside the battery is avoided, and the safety of the battery is improved.
In addition, the battery manufactured by the method has the advantages that the arrangement of the diaphragm is omitted, the spacing distance between the electrode plates is optimized, the proportion of active substances in the electrode plates is increased under the condition that the thickness of the battery is not changed, and therefore the energy density of the battery is improved.
The embodiment of the invention also provides a battery, which comprises a first pole piece, a second pole piece and electrolyte, wherein at least one of the first pole piece and the second pole piece is the above electrode plate.
It should be noted that, the implementation manner of the embodiment of the electrode tab is also applicable to the embodiment of the battery, and the same technical effect can be achieved, and details are not described herein again.
The effect of the battery manufactured by the battery manufacturing method provided by the invention is described based on multiple sets of experiments.
Comparative example 1:
preparing a negative plate: according to the weight percentage, 95% of negative electrode active material (artificial graphite), 1% of negative electrode conductive agent (conductive carbon black SP), 2% of sodium carboxymethylcellulose (CMC), 2% of Styrene Butadiene Rubber (SBR) and solvent are selected from deionized water to prepare negative electrode artificial graphite slurry, the negative electrode artificial graphite slurry is coated on negative electrode current collectors (two sides of copper foil), and a negative electrode sheet is prepared after drying, rolling, slitting and welding negative electrode lugs;
preparing a positive plate: adding 96% of positive active material (lithium cobaltate), 2% of positive conductive agent (conductive carbon black SP) and 2% of polyvinylidene fluoride (PVDF) into N-methyl pyrrolidone (NMP) according to weight parts to prepare positive lithium cobaltate slurry, coating the positive lithium cobaltate slurry on positive current collectors (two sides of an aluminum foil), and preparing a positive plate after drying, rolling, slitting and welding positive lugs;
preparing an electrolyte: the electrolyte consists of lithium salt and a solvent, wherein the organic solvent is a mixture of propylene carbonate, ethylene carbonate, dimethyl carbonate and three organic solvents, the volume ratio of the three solvents is 1:1:1, the lithium salt is LiPF6, and the concentration is 1M;
preparing a diaphragm: the thickness of the polyethylene diaphragm prepared by the conventional technical means is 10 microns;
preparing a lithium ion battery: after stacking positive plate, diaphragm and negative plate in proper order, convolute and form electric core for through the diaphragm interval setting between positive plate and the negative plate, arrange the aluminium-plastic membrane in with electric core, toast the dewatering, pour into electrolyte into again, to electric core go on turn into, process such as ageing, obtain lithium ion battery.
Example 1:
preparing a negative plate: firstly, according to the weight percentage, preparing 95% of negative electrode active material (artificial graphite), 1% of negative electrode conductive agent (conductive carbon black SP), 2% of sodium carboxymethyl cellulose (CMC), 2% of Styrene Butadiene Rubber (SBR) and deionized water as a solvent to obtain negative electrode artificial graphite slurry, and respectively coating the negative electrode artificial graphite slurry on a first surface and a second surface which are arranged on the opposite sides of a negative electrode current collector 101 (copper foil is selected) to form an active layer 102; then, adding 50% of hexagonal boron nitride, 45% of a tough material (polyethylene oxide is selected) and 5% of an adhesive (polyvinylidene fluoride is selected) into a solvent (N-methylpyrrolidone is selected) according to the weight percentage to prepare isolation layer slurry, respectively coating the isolation layer slurry on the active layer 102 to form an isolation layer 103, and completely covering the active layer 102 by the isolation layer 103 to ensure that the thickness of the isolation layer exceeds 0.5mm in the head, tail and width directions of the pole piece so as to prevent the contact of a positive electrode and a negative electrode; drying, rolling, cutting and welding the negative electrode lug to obtain a negative electrode sheet; wherein the one-sided thickness of the isolation layer 103 may be 5 um.
Preparing a positive plate: adding 96% of positive active material (lithium cobaltate), 2% of positive conductive agent (conductive carbon black SP) and 2% of polyvinylidene fluoride (PVDF) into N-methyl pyrrolidone (NMP) to prepare positive lithium cobaltate slurry, coating the slurry on positive current collectors (two sides of an aluminum foil), and preparing a positive plate after drying, rolling, slitting and welding positive lugs;
preparing an electrolyte: the electrolyte consists of lithium salt and a solvent, wherein the organic solvent is a mixture of propylene carbonate, ethylene carbonate, dimethyl carbonate and three organic solvents, the volume ratio of the three solvents is 1:1:1, the lithium salt is LiPF6, and the concentration is 1M;
preparing a lithium ion battery: and (3) winding the positive plate and the negative plate with the isolation layer 103 into a battery cell, placing the battery cell in an aluminum-plastic film, baking to remove water, injecting electrolyte, and performing procedures such as formation, aging and the like on the battery cell to obtain the lithium ion battery.
Example 2:
the only difference between example 2 and example 1 is the proportioning of the slurry of the separation layer 103. In example 2, the composition of the isolation layer is 50% of hexagonal boron nitride, 44% of a ductile material (polyethylene oxide is selected), 5% of an adhesive (polyvinylidene fluoride is selected), and 1% of a lithium salt (lithium hexafluorophosphate is selected).
Example 3:
the only difference between example 3 and example 1 is the proportioning of the slurry of the separation layer 103. In example 3, the composition of the isolation layer is 50% of hexagonal boron nitride, 42% of a ductile material (polyethylene oxide is selected), 5% of an adhesive (polyvinylidene fluoride is selected), and 3% of a lithium salt (lithium hexafluorophosphate is selected).
Example 4:
example 4 differs from example 1 only in the proportioning of the slurry of the separation layer 103. In example 4, the composition of the isolation layer is 50% hexagonal boron nitride, 40% flexible material (polyethylene oxide is selected), 5% adhesive (polyvinylidene fluoride is selected), and 5% lithium salt (lithium hexafluorophosphate is selected).
Example 5:
the only difference between example 5 and example 1 is the proportioning of the slurry of the separation layer 103. In example 5, the composition of the isolation layer is 50% hexagonal boron nitride, 38% flexible material (polyethylene oxide is selected), 5% adhesive (polyvinylidene fluoride is selected), and 7% lithium salt (lithium hexafluorophosphate is selected).
Example 6:
example 6 differs from example 3 only in that the single-sided thickness of the isolation layer 103 in example 6 is 3 um.
Example 7:
example 7 differs from example 3 only in that the single-sided thickness of the isolation layer 103 in example 7 is 7 um.
Example 8:
example 8 differs from example 3 only in that the single-sided thickness of the isolation layer 103 in example 8 is 9 um.
Example 9:
example 9 differs from example 3 only in that the single-sided thickness of the isolation layer 103 in example 9 is 10 um.
The batteries prepared in examples 1 to 9 and comparative example 1 were subjected to a performance test, a K value test, and a first coulombic efficiency test, respectively.
Cycle capacity retention at 25 ℃ test: and testing the voltage, the internal resistance, the thickness and the direct current internal resistance of the battery cell at normal temperature. And (3) placing the cell in an environment with the temperature of 25 +/-3 ℃, standing for 10min, and discharging to the cutoff voltage of 3.0V at the current of 0.2C. Standing for 10min, charging to the upper limit voltage of 4.45V with a constant current of 0.5C, maintaining constant voltage charging at 4.45V after the upper limit voltage is reached, and cutting off the current of 0.02C. Standing for 10min, discharging to lower limit voltage of 3V at 0.2C (performing initial capacity test).
The cycle test was as follows: 1. standing for 10min, charging to upper limit voltage of 4.45V at 0.5C, maintaining constant voltage charging at 4.45V after reaching the upper limit voltage, and stopping current at 0.02C. 2. Standing for 10min, discharging at 0.2C to cut-off voltage of 3V, and repeating 1-2 steps for 300 times. Wherein, every 50 times, full-electricity test process data, voltage, internal resistance, thickness and direct-current internal resistance are repeatedly tested at 25 ℃ every 100 times. And measuring the data, voltage, internal resistance, thickness and direct current internal resistance in the full charge state after circulation. Capacity retention rate ═ C 2 /C 1 *100％，C 1 For initial capacity testing, C 2 The 300 th discharge capacity.
And (3) testing the K value: the K value is the voltage drop per unit time, usually expressed in mV/h, and is used to measure the self-discharge rate of lithium ion batteries. Time t 1 Measurement of OCV 1 At t 2 Time-dependent test OCV 2 ；
Wherein K is OCV 1 -OCV 2 /t 1 -t 2 。
The first coulombic efficiency test, called first effect for short, of the lithium ion battery is used for quantifying one performance index of a lithium ion battery cathode material and is defined as the proportion of discharge capacity and charge capacity of the lithium ion battery in first charge-discharge cycle. There are two main loss modes: 1. generating an SEI film; 2. the negative electrode irreversibly intercalates lithium.
Wherein the energy density can be expressed as:
E＝C*U/w*t*l
e: Wh/L, volumetric energy density;
u: v, average cell operating voltage;
c: mAh, cell off-site capacity;
w: cm, cell width;
t: cm, the thickness of the battery cell;
l: cm, cell length.
The batteries manufactured in examples 1 to 9 and comparative example 1 were subjected to the above-described tests, and the test results thereof were recorded as shown in the following table 1:
table 1: results of the related tests of examples 1-9 and comparative example 1
Figure BDA0003699524280000101
Through the comparison, the capacity retention rates are consistent after 300 cycles and the change is ignored when the examples 1-9 are compared with the comparative example 1, and compared with the examples 6, 7, 8 and 9 and the comparative example 1, the energy density is smaller along with the increase of the thickness of the isolating layer, and the isolating layer replaces the diaphragm, so that the energy density is improved; in examples 1, 2, 3, 4, 5 and comparative example 1, the lithium salt helps to improve the first coulombic efficiency of the negative electrode; comparing the K values from the comparative example and the example, the isolation layer is too thin with the risk of short circuit;
in conclusion, the electrode plate and the lithium ion battery provided by the invention can improve the energy density and the first coulombic efficiency of the negative electrode; and the isolating layer 103 replaces the diaphragms arranged on the two sides of the electrode plates, and the isolating effect of the isolating layer 103 ensures that the electrode plates with different polarities can be directly laminated or wound to form a battery cell in the preparation process of the battery, so that the battery structure is simplified, the process of arranging the diaphragms is reduced, the internal short circuit of the battery caused by the conditions of dislocation, falling and the like of the diaphragms is avoided, and the safety of the battery is improved.
Practical applications of the present invention include, but are not limited to, the above-described embodiments.
The embodiment of the invention also provides electronic equipment, and the electronic equipment comprises the battery.
The electronic device may be a notebook computer, a smart phone, or the like, and is not limited herein. The implementation manner of the embodiment of the battery is also suitable for the embodiment of the electronic device, and can achieve the same technical effect, which is not described herein again.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element. Furthermore, it should be noted that the scope of the methods and apparatus of embodiments of the present invention is not limited to performing functions in the order discussed, but may include performing functions in a substantially simultaneous manner or in a reverse order depending on the functionality involved, e.g., the methods described may be performed in an order different than that described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.
While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (10)

1. An electrode sheet, comprising a current collector and an isolation layer, the current collector comprising a first surface and a second surface, the isolation layer disposed on at least one of the first surface and the second surface, the isolation layer comprising a composition comprising hexagonal boron nitride.
2. The electrode sheet of claim 1, wherein the composition of the separator layer comprises a lithium salt.
3. The electrode sheet of claim 1, wherein the composition of the separator layer comprises a ductile material.
4. The electrode sheet according to claim 1, wherein the components of the isolation layer comprise hexagonal boron nitride, a tough material, an adhesive and a lithium salt, and the ratio of the hexagonal boron nitride to the tough material to the adhesive to the lithium salt is as follows: 30 to 60 wt%, 1 to 10 wt%.
5. The electrode sheet of claim 1, further comprising an active layer disposed between the current collector and the isolation layer, wherein a projection of the isolation layer on the current collector is greater than a projection of the active layer on the current collector.
6. The electrode sheet according to claim 1, wherein the thickness of the separator layer is 3 to 25 micrometers.
7. The electrode sheet as defined in claim 1, wherein the separator layer has a porosity of 25 to 50%.
8. The electrode sheet of claim 4, wherein the tough material comprises at least one of graphene oxide, a two-dimensional material, polyethylene oxide, polyester resin, fiber paper, non-woven fabric, and nanocellulose; and/or the presence of a gas in the gas,
the adhesive comprises at least one of polyvinyl alcohol, acrylonitrile, acrylic acid, styrene butadiene rubber, carboxymethyl cellulose, polyvinylidene fluoride, polyvinylpyrrolidone and polyimide; and/or the presence of a gas in the gas,
the lithium salt includes at least one of lithium perchlorate, lithium chloride, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium tetrafluoroborate and lithium bis fluorosulfonylimide.
9. A battery comprising a first pole piece, a second pole piece, and an electrolyte, at least one of the first pole piece and the second pole piece being an electrode sheet of any one of claims 1 to 8.
10. A method of making a battery, the method comprising:
preparing a first pole piece and a second pole piece, wherein at least one of the first pole piece and the second pole piece comprises an isolation layer, and the isolation layer comprises hexagonal boron nitride;
winding or laminating the first pole piece and the second pole piece to form a battery core;
and placing the battery core in an aluminum-plastic film, and injecting electrolyte to form the battery.
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