CN116646470A - Positive electrode plate, preparation method of positive electrode plate, battery and electric equipment - Google Patents

Positive electrode plate, preparation method of positive electrode plate, battery and electric equipment Download PDF

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Publication number
CN116646470A
CN116646470A CN202310876212.5A CN202310876212A CN116646470A CN 116646470 A CN116646470 A CN 116646470A CN 202310876212 A CN202310876212 A CN 202310876212A CN 116646470 A CN116646470 A CN 116646470A
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CN
China
Prior art keywords
positive electrode
electrolyte
additive
electrode sheet
battery
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CN202310876212.5A
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Chinese (zh)
Inventor
吴凯
黄滔
谢岚
吴小辉
林真
李伟
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Priority to CN202310876212.5A priority Critical patent/CN116646470A/en
Publication of CN116646470A publication Critical patent/CN116646470A/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
    • 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
    • H01M10/052—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
    • H01M10/42—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
    • H01M4/13—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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2004/028—Positive 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

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

Abstract

The application discloses a positive pole piece, a preparation method of the positive pole piece, a battery and electric equipment. The positive pole piece comprises a base layer and an active layer; the active layer is disposed on the base layer, and the active layer includes a positive electrode active material and an organic compound-based additive that is soluble in the electrolyte. By the mode, the charging rate can be considered on the basis of improving the energy density of the battery; ion transmission efficiency, immersion effect, etc.

Description

Positive electrode plate, preparation method of positive electrode plate, battery and electric equipment
Technical Field
The application relates to the technical field of new energy, in particular to a positive pole piece, a preparation method of the positive pole piece, a battery and electric equipment.
Background
In general, increasing the thickness of the electrode sheet can increase the energy density of the battery, but thickening the sheet significantly reduces the active ion transport rate and entails the risk of poor electrolyte infiltration.
Disclosure of Invention
The application mainly solves the technical problem of providing a positive pole piece, a preparation method of the positive pole piece, a battery and electric equipment, and can give consideration to the charging multiplying power on the basis of improving the energy density of the battery; ion transmission efficiency, immersion effect, etc.
In order to solve the technical problems, the application adopts a technical scheme that: providing a positive electrode plate, wherein the positive electrode plate comprises a base layer and an active layer; the active layer is disposed on the base layer, and the active layer includes a positive electrode active material and an organic compound-based additive that is soluble in the electrolyte. Through the arrangement, when the positive electrode plate is soaked in the electrolyte, the additive can be dissolved into the electrolyte, so that pores are formed in the active layer, namely, the porosity of the positive electrode plate can be improved, and the migration rate of active ions is further improved; meanwhile, the positions occupied by the additives are filled with the electrolyte, so that the contact area of the active materials and the electrolyte can be remarkably increased, and the infiltration effect of the electrolyte is further improved. Further, the additive is selected as an organic compound substance, so that the additive is better in compatibility with the positive electrode slurry in the preparation process of the positive electrode plate, and can be uniformly dissolved and dispersed in the positive electrode slurry, so that the distribution uniformity of the additive in the active layer is improved when the active coating is formed, the distribution uniformity of pores in the positive electrode plate is further improved, and the infiltration effect and the ion transport rate of the electrode plate are improved to a greater extent.
In one embodiment, the organic compound-based additive has a boiling point greater than 150 ℃ and a melting point greater than 30 ℃. By this arrangement, the additive will not volatilize during the drying of the electrode; and the pole piece is solid after being cooled to room temperature, so that the problem of low strength of the pole piece caused by influence on the mechanical stability of the active layer due to excessive liquid phase components in the positive electrode active layer is solved.
In one embodiment, the organic compound-based additive is capable of being dissolved in a polar organic solvent. By this arrangement, the solubility and dissolution rate of the additive in the electrolyte can be improved; the solubility of the additive in the positive electrode slurry is improved, so that the additive is completely and uniformly dissolved in the positive electrode slurry, and the distribution uniformity of the additive in the positive electrode active layer is improved.
In one embodiment, the polar organic solvent comprises one or more of N-methylpyrrolidone, N-dimethylformamide, N-diethylformamide, dimethylsulfoxide, pyridine, and tetrahydrofuran. The solubility of the organic additive in the positive electrode slurry can be improved, so that the additive is completely and uniformly dissolved in the positive electrode slurry, and the distribution uniformity of the additive in the positive electrode active layer is improved.
In one embodiment, the organic compound-based additive includes a solvent for the electrolyte and/or an additive for the electrolyte. The electrolyte additive can be used as the electrolyte additive when the additive is dissolved in the electrolyte, so that the battery performance is improved, or the electrolyte additive can be used as the electrolyte cosolvent to supplement the electrolyte, so that the risk of service life reduction of the battery caused by electrolyte consumption is reduced.
In one embodiment, the organic compound-based additive comprises one or more of ethylene carbonate, 1, 3-propane sultone. The contents of the two substances in the electrolyte are higher; the additive amount can be increased, and the porosity of the infiltrated positive electrode plate can be increased; and after the electrolyte is dissolved into the electrolyte, the performance of the battery is not affected.
In one embodiment, the electrolyte includes one or more of carbonate solvents, ether solvents. Can facilitate the transmission of active ions, reduce side reactions on the surface of the electrode and improve the stability of the battery.
In one embodiment, the active layer has a thickness of 80-200 μm; optionally 120-165 μm. The energy density of the battery can be improved.
In one embodiment, the additive comprises 0.2% -1% by weight of the active layer. The porosity of the obtained positive electrode plate can be regulated and controlled by regulating and controlling the addition amount of the additive, so that the ion migration rate and the electrolyte infiltration effect can be improved.
In one embodiment, the active layer further comprises a conductive agent and a binder; optionally, the conductive agent includes one or more of conductive carbon black, conductive graphite, carbon fiber, carbon nanotube, graphene, ketjen black, and acetylene black; optionally, the binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, acrylic ester and polyurethane. The conductivity and the adhesion stability of the active layer can be improved, and the occurrence probability of powder falling is reduced.
In order to solve the technical problems, the application adopts another technical scheme that: the preparation method comprises the steps of mixing an anode active material, an organic compound additive and a solvent to obtain anode slurry; coating the positive electrode slurry on a base layer, and drying to obtain a positive electrode plate; wherein, the organic compound additive of the positive electrode plate can be dissolved in the electrolyte. The prepared positive pole piece has the excellent performance.
In one embodiment, the mass ratio of the positive electrode active material to the additive is 97:1 to 97:5. The porosity of the obtained positive electrode plate can be regulated and controlled by regulating and controlling the addition amount of the additive, so that the ion migration rate and the electrolyte infiltration effect can be improved.
In order to solve the technical problems, the application adopts another technical scheme that: the battery comprises a porous positive electrode plate, wherein the porous positive electrode plate is obtained by immersing the positive electrode plate in electrolyte. The positive pole piece improves the energy density of the battery and gives consideration to the charging multiplying power; ion transmission efficiency, immersion effect, etc.
In one embodiment, the porosity of the porous positive electrode sheet is 20% -35%.
In order to solve the technical problems, the application adopts another technical scheme that: an electric device is provided, which comprises the battery. The electric equipment has at least the same advantages as the battery, and can improve the storage of the electric equipment.
The foregoing description is only an overview of the present application, and is intended to be implemented in accordance with the teachings of the present application in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present application more readily apparent.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic structural view of a positive pole piece according to one or more embodiments;
FIG. 2 is a schematic diagram of a change in state of a positive pole piece according to one or more embodiments;
FIG. 3 is a flow diagram of a method of making a positive electrode sheet according to one or more embodiments;
fig. 4 is an exploded view of a battery according to one or more embodiments;
fig. 5 is an exploded view of a battery cell according to one or more embodiments;
FIG. 6 is a schematic structural view of a vehicle according to one or more embodiments.
In the accompanying drawings:
1000. a vehicle; 300. a motor; 200. a controller; 100. a battery; 10. a case; 11. a first portion; 12. a second portion; 20. a battery cell; 21. an end cap; 21a, electrode terminals; 22. a housing; 23. an electrode assembly;
40. a positive electrode sheet; 41. a base layer; 43. an active layer; 431. an additive; 433. a void; 50. a porous positive electrode plate.
Detailed Description
In order to make the objects, technical solutions and effects of the present application clearer and more specific, embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present application, and thus are merely examples, and are not intended to limit the scope of the present application.
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 application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description of the application and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion.
In the description of embodiments of the present application, the technical terms "first," "second," and the like are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the term "plurality" means two or more (including two), and similarly, "plural sets" means two or more (including two), and "plural sheets" means two or more (including two), unless otherwise specifically defined.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, and indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
Amounts, ratios, and other numerical values are presented herein in a range format. It is to be understood that such range format is used for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited.
All the steps of the present application may be performed sequentially, randomly, or in parallel, preferably sequentially, unless otherwise specified. For example, the method comprises steps (a) and (b), meaning that the method may comprise steps (a) and (b) performed sequentially, may comprise steps (b) and (a) performed sequentially, and may be performed simultaneously. For example, the method may further comprise step (c), meaning that step (c) may be added to the method in any order, e.g., the method may comprise steps (a), (b) and (c), may also comprise steps (a), (c) and (b), may also comprise steps (c), (a) and (b), etc.
With the continuous development of new energy technology, the power battery is widely applied to various fields of various consumer electronic products, electric vehicles, aerospace and the like. In particular, with the continuous acceleration of the progress of the electric motor of automobiles in recent years, higher demands are also being made on the energy density and the rate capability of batteries as power sources.
Currently, the following methods are preferable for improving the energy density and the rate capability of the battery. Such as increasing the thickness of the positive and negative pole pieces, increasing the compaction density of the pole piece active material coating, increasing the gram capacity of the active material, and increasing the porosity of the pole piece active material coating, but in the above method, it is difficult to achieve both energy density and rate capability. If the thickness of the positive and negative electrode plates is increased, the ion transmission rate is obviously reduced, and the risk of poor electrolyte infiltration is accompanied. However, increasing the thickness of the pole piece is the most direct and simple method for increasing the energy density of the battery. Therefore, how to solve the problems of low ion transmission rate, uneven electrolyte infiltration and the like caused by the thick electrode is a technical difficulty which needs to be solved in the field. In view of the above, the application provides a thick positive electrode plate with high ion transmission rate and uniform electrolyte infiltration, a preparation method thereof, a battery and electric equipment.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a positive electrode sheet according to one or more embodiments. The application provides a positive electrode sheet 40, wherein the positive electrode sheet 40 comprises a base layer 41 and an active layer 43; the active layer 43 is disposed on the base layer 41, and the active layer 43 includes a positive electrode active material and an organic compound-based additive 431, and the organic compound-based additive 431 is soluble in an electrolyte.
The base layer 41 is a conductive base layer, and may be a current collector, and may be a metal foil or a composite material, for example, a composite conductive material formed by mixing a metal material with a polymer base material. For example, as the metal foil, aluminum foil may be used. The composite conductive material may include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material base layer. The composite conductive material may be formed by forming a metal material (aluminum, aluminum alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.). The base layer 41 may be cube-shaped with a first surface and a second surface disposed opposite in the thickness direction thereof for carrying the disposition of the other layer structures.
The active layer 43 includes at least a positive electrode active material. The active layer 43 may be in the form of a layered structure formed of an active material as a main material, and may be in the form of a layered film. The active layer 43 may be provided only on the first surface or the second surface of the base layer 41, or may be provided on both the first surface and the second surface of the base layer 41. The active layer 43 may be directly disposed on the surface of the base layer 41, or another functional material layer may be disposed between the active layer 43 and the base layer 41. The active layer 43 is the main structural layer of the electrode to realize the basic functions of the battery.
In this embodiment, the active layer 43 further includes an organic compound-based additive 431 that is soluble in the electrolyte. The electrolyte can be completely dissolved in the electrolyte or partially dissolved in the electrolyte, that is, the specific dissolution degree of the additive in the electrolyte is not excessively limited, and only a certain degree of dissolution is required. Preferably capable of being completely dissolved in the electrolyte. When the positive electrode sheet 40 is immersed in the electrolyte, the additive 431 can be dissolved into the electrolyte, so that pores are formed in the active layer 43, that is, the porosity of the positive electrode sheet 40 can be improved, and the migration rate of active ions can be further improved; meanwhile, the position occupied by the additive 431 is filled with the electrolyte, so that the contact area of the active material and the electrolyte can be remarkably increased, and the infiltration effect of the electrolyte is further improved. Further, the additive is selected as an organic compound substance, so that the additive is better in compatibility with the positive electrode slurry in the preparation process of the positive electrode plate, and can be uniformly dissolved and dispersed in the positive electrode slurry, so that the distribution uniformity of the additive in the active layer is improved when the active coating is formed, the distribution uniformity of pores in the positive electrode plate is further improved, and the infiltration effect and the ion transport rate of the electrode plate are improved to a greater extent.
Referring to fig. 2, fig. 2 is a schematic diagram illustrating a change in state of a positive pole piece according to one or more embodiments. The application provides a battery, which comprises a porous positive electrode plate 50, wherein the porous positive electrode plate 50 is obtained by soaking the positive electrode plate 40 in electrolyte in any embodiment.
As shown in fig. 2, the positive electrode sheet 40 includes a base layer 41 and an active layer 43, and the active layer 43 includes a positive electrode active material and an organic compound-based additive 431. When the positive electrode sheet 40 is immersed in the electrolyte, the additive 431 can be dissolved into the electrolyte, so that the pores 433 are formed in the active layer 43, resulting in the porous positive electrode sheet 50. The porosity of the obtained porous positive electrode plate 50 is high, so that the migration rate of active ions can be improved; meanwhile, the position occupied by the additive 431 is filled with the electrolyte, so that the contact area of the active material and the electrolyte can be remarkably increased, and the infiltration effect of the electrolyte is further improved.
In one embodiment, the porosity of the porous positive electrode sheet is 20% -35%. For example, 20%, 23%, 25%, 28%, 30%, 32%, 35%, etc.; or the composition may be in the range of 20% to 25%, 25% to 30%, 30% to 35%, etc. After the electrolyte is soaked, the porosity of the positive electrode plate is larger, and the soaking effect can be improved.
Referring to fig. 3, fig. 3 is a flow chart illustrating a method of manufacturing a positive electrode sheet according to one or more embodiments. The application provides a preparation method of a positive pole piece, which comprises the following steps:
s110: and mixing the positive electrode active material, the organic compound additive and the solvent to obtain positive electrode slurry.
S120: coating the positive electrode slurry on a base layer, and drying to obtain a positive electrode plate; wherein the organic compound additive of the positive electrode plate can be dissolved in the electrolyte.
In one embodiment, the solvent used to prepare the positive electrode slurry includes one or more of N-methylpyrrolidone (NMP), N-Dimethylformamide (DMF), N-Diethylformamide (DEF), dimethylsulfoxide (DMSO), pyridine, and Tetrahydrofuran (THF). By selecting these solvents, the stability and dispersion uniformity of the positive electrode active material in the slurry can be improved; meanwhile, the solubility of the organic additives in the slurry can be improved, and the problems of unstable slurry, easiness in layering and sedimentation and the like are solved. The selected solvent is a non-aqueous system, so that the problem of thermal hydrolysis of the additive can be solved.
In one embodiment, the mass ratio of the positive electrode active material to the additive is 97:1 to 97:5. For example, 97:1, 97:2, 97:3, 97:4, 97:5, etc. The porosity of the obtained positive electrode plate can be regulated and controlled by regulating and controlling the addition amount of the additive, so that the ion migration rate and the electrolyte infiltration effect can be improved.
In one embodiment, the positive electrode sheet coated with the positive electrode slurry may be heated, dried, and cooled to obtain the positive electrode sheet. The heating and baking temperature is 90-120deg.C, such as 90deg.C, 95deg.C, 100deg.C, 105, 110deg.C, 115, 120deg.C, etc. The positive electrode active material and the additive are not thermally decomposed due to overheating or the like on the basis of promoting the solvent volatile slurry to solidify by controlling the baking temperature.
The application is based on the preparation method of the positive pole piece, and starts from the principle of induced phase separation, in particular to the principle of double induced phase separation of heat and solvent, so as to prepare the positive pole piece with optimized performance.
Specifically, the additive is added in the stirring process of the positive electrode slurry, so that the additive is completely and uniformly dissolved and dispersed in the solvent, the solvent volatilizes due to low boiling point in the coating baking process because of higher baking temperature, the additive remains in the positive electrode active layer because of high boiling point, and the additive solidifies into a solid phase in the positive electrode active coating layer due to higher melting point in the subsequent cooling and winding process. Wherein, since the additive is uniformly dispersed in the solvent of the positive electrode slurry, the additive in the solid phase is uniformly dispersed in the active coating layer after the solvent is volatilized. In the process of assembling the positive electrode plate into a battery, particularly in the liquid injection process and the standing process, the solid phase additive in the active coating can be dissolved by the injected electrolyte, namely the electrolyte can fill the position occupied by the solid phase additive, the positive electrode plate prepared by the method can obviously increase the contact area of active substances and the electrolyte, obviously improve the infiltration effect of the electrolyte on the battery plate, effectively improve the migration rate of active ions in the electrode material, reduce the polarization internal resistance and improve the multiplying power performance of the plate.
In one embodiment, the additive is capable of being dissolved in a polar organic solvent. Alternatively, the polar organic solvent includes, but is not limited to, one or more of N-methylpyrrolidone, N-dimethylformamide, N-diethylformamide, dimethylsulfoxide, pyridine, and tetrahydrofuran.
The electrolyte solvent is mostly a polar solvent, and for example, the electrolyte includes one or more of carbonate solvents and ether solvents. In order to increase the solubility and dissolution rate of the additive in the electrolyte, the additive is preferably a compound capable of being dissolved in a polar organic solvent. Further, in order to improve the uniformity of the distribution of the additive in the active layer, the solvent used in the positive electrode slurry is usually a polar solvent, and the uniformity of the distribution of the additive in the positive electrode slurry is improved, so that the additive is completely and uniformly dissolved in the positive electrode slurry, and the uniformity of the distribution of the additive in the positive electrode active layer can be improved.
In one embodiment, the additive has a boiling point greater than 150 ℃ and a melting point greater than 30 ℃. For example, the boiling point of the additive may be greater than 160 ℃, 170 ℃, 180 ℃, etc.; the melting point of the additive may be greater than 35 ℃, 40 ℃, 50 ℃, etc.
In the process of manufacturing the positive electrode sheet, the additive is generally dissolved in the solvent of the positive electrode slurry, and after the solvent volatilizes, the additive is dissolved out to form a solid phase so as to occupy the space of the active layer, and after the additive is dissolved by the electrolyte, the pore is formed in the positive electrode active layer. Based on this, it is necessary that the additive has a higher boiling point, at least higher than the boiling point of the solvent used in the positive electrode slurry, so that the additive does not volatilize together when the solvent volatilizes; further, the baking and drying temperature of the positive electrode plate is higher than that of the positive electrode plate, so that the additive cannot volatilize in the drying process; furthermore, the melting point of the additive should be higher than room temperature to be solid after the pole piece is cooled to room temperature, so as to prevent the problem of low strength of the pole piece caused by influence of excessive liquid phase components in the positive electrode active layer on the mechanical stability of the active layer. Therefore, the additive is preferably an organic compound having a boiling point greater than 150 ℃ and a melting point greater than 30 ℃.
In one embodiment, the additive should have good thermal and solvent stability so that the additive is relatively stable in the positive electrode slurry and does not chemically react with the solvent of the slurry or other additives; meanwhile, the pole piece cannot be thermally decomposed in the drying process. Further, the additives do not negatively affect the battery performance after dissolution in the electrolyte.
In one embodiment, the additive includes a solvent for the electrolyte and/or an additive for the electrolyte. By selecting the solvent and/or additive used in the electrolyte as the additive of the active layer, the additive can be used as the electrolyte additive when dissolved in the electrolyte, thereby improving the battery performance or being used as the electrolyte cosolvent to supplement the electrolyte, and reducing the risk of the service life reduction of the battery caused by electrolyte consumption.
In one embodiment, the additive comprises one or more of ethylene carbonate, 1,3-propane sultone.
Wherein the boiling point of the ethylene carbonate (Ethylene Carbonate, EC) is 248 ℃/760mm Hg,243-244 ℃/740mmHg; the melting point is 35-38 ℃; transparent colorless liquid at 35 ℃ and crystalline solid at room temperature. Ethylene carbonate is an organic solvent with excellent performance and is often used as an electrolyte solvent; it is capable of dissolving a variety of substances, and is also miscible with a variety of solvents. 1,3-propane sultone (1, 3-Propanesultone,1, 3-PS) has a boiling point of 180 ℃/30mmHg and a melting point of 30-33 ℃; slightly soluble in water and easily soluble in organic solvents.
Further, ethylene carbonate is used as a solvent of the electrolyte, and a component existing in a large amount in the electrolyte; even if the amount of the additive is large, the electrolyte is dissolved therein, and thus the battery performance is hardly affected. 1,3-propane sultone is also commonly added as an additive to an electrolyte, and similarly, does not affect battery performance after it is dissolved into the electrolyte.
In one embodiment, the additive comprises 0.2% -1% by weight of the active layer. For example, 0.2%, 0.5%, 0.8%, 1.0% and the like are possible. The porosity of the obtained positive electrode plate can be regulated and controlled by regulating and controlling the addition amount of the additive, so that the ion migration rate and the electrolyte infiltration effect can be improved.
In one embodiment, the active layer further includes a conductive agent, thereby imparting conductivity to the electrode. The positive electrode conductive material may include any conductive material as long as it does not cause chemical change. Non-limiting examples of positive electrode conductive materials include carbon-based materials (e.g., natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fibers, etc.), metal-based materials (e.g., metal powders, metal fibers, etc., including, for example, copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives), and mixtures thereof. Optionally, the conductive agent includes one or more of conductive carbon black, conductive graphite, carbon fiber, carbon nanotube, graphene, ketjen black, and acetylene black.
In one embodiment, the active layer further includes a binder to improve adhesion stability of the active layer and reduce the probability of powder loss. The binder can be one or more of Styrene Butadiene Rubber (SBR), water-based acrylic resin (water-based acrylic resin), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyacrylic acid (PAA), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA) and polyvinyl butyral (PVB). Optionally, the binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, acrylic ester and polyurethane.
In one embodiment, the active layer further includes other optional adjuvants, which may be thickening and dispersing agents (e.g., sodium carboxymethylcellulose CMC-Na), PTC thermistor materials.
In the above embodiment, in the liquid injection process and the standing process of the battery assembly process, the solid phase additive in the active coating is dissolved by the injected electrolyte, that is, the electrolyte fills the position occupied by the solid phase additive, so that the contact area between the active substance and the electrolyte is greatly increased, the infiltration effect of the electrolyte on the electrode plate is improved, and the electrolyte infiltration effect of the thick electrode is improved; the migration rate of active ions in the electrode material can be effectively improved, the polarization internal resistance is reduced, and the multiplying power performance of the pole piece is improved. Therefore, through the design, the thickness of the positive electrode plate can be made thick, and the charging multiplying power can be considered on the basis of improving the energy density of the battery; ion transmission efficiency, immersion effect, etc.
In one embodiment, the active layer of the positive electrode sheet has a thickness of 80-200 μm; optionally 120-165 μm. For example, 80 μm, 85 μm, 90 μm, 100 μm, 108 μm, 116 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, 150 μm, 155 μm, 160 μm, 165 μm, 170 μm, 180 μm, 190 μm, 200 μm, etc. are possible. Or any two of the above values, for example, 80-100 μm, 90-108 μm, 100-120 μm, 120-130 μm, 125-135 μm, 130-150 μm, 150-165 μm, 170-200 μm, etc.
In one embodiment, the total thickness of the positive electrode sheet may be 88-213 μm; optionally 130-165 μm. Wherein the base layer is 8-13 μm, and the thickness of the active layer is 80-200 μm.
In the embodiment, the content of the active material can be increased by increasing the thickness of the active layer so as to improve the energy density of the battery, and meanwhile, the additive is dissolved into the electrolyte, so that the diffusion path of the electrolyte is increased, the electrolyte wettability of the pole piece is improved, and the porosity of the pole piece is improved; the migration rate of active ions in the electrode material is effectively improved, the polarization internal resistance is reduced, and the multiplying power performance of the pole piece is improved. Further, the dissolved additive may act in the electrolyte to supplement the electrolyte or act as an electrolyte additive without negatively affecting the battery.
The present application also provides an electrochemical device including any device in which an electrochemical reaction occurs, and specific examples thereof include all kinds of primary or secondary batteries. For example, the secondary batteries may be lithium batteries, sodium batteries, potassium batteries, and the like. The lithium secondary battery may include a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery.
Referring to fig. 4, fig. 4 is a schematic diagram of an exploded structure of a battery according to one or more embodiments. The battery 100 includes a case 10 and a battery cell 20, and the battery cell 20 is accommodated in the case 10. The case 10 is used to provide an accommodating space for the battery cell 20, and the case 10 may have various structures. In some embodiments, the case 10 may include a first portion 11 and a second portion 12, the first portion 11 and the second portion 12 being overlapped with each other, the first portion 11 and the second portion 12 together defining an accommodating space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one end opened, the first portion 11 may be a plate-shaped structure, and the first portion 11 covers the opening side of the second portion 12, so that the first portion 11 and the second portion 12 together define a containing space; the first portion 11 and the second portion 12 may be hollow structures each having an opening at one side, and the opening side of the first portion 11 is engaged with the opening side of the second portion 12. Of course, the case 10 formed by the first portion 11 and the second portion 12 may be of various shapes, such as a cylinder, a rectangular parallelepiped, or the like.
In the battery 100, the plurality of battery cells 20 may be connected in series, parallel or a series-parallel connection, wherein the series-parallel connection refers to that the plurality of battery cells 20 are connected in series or parallel. The plurality of battery cells 20 can be directly connected in series or in parallel or in series-parallel, and then the whole formed by the plurality of battery cells 20 is accommodated in the box 10; of course, the battery 100 may also be a battery module formed by connecting a plurality of battery cells 20 in series or parallel or series-parallel connection, and a plurality of battery modules are then connected in series or parallel or series-parallel connection to form a whole and are accommodated in the case 10. The battery 100 may further include other structures, for example, the battery 100 may further include a bus member for making electrical connection between the plurality of battery cells 20.
Wherein each battery cell 20 may be a secondary battery or a primary battery; but not limited to, lithium sulfur batteries, sodium ion batteries, or magnesium ion batteries. The battery cell 20 may be in the shape of a cylinder, a flat body, a rectangular parallelepiped, or other shapes, etc.
Referring to fig. 5, fig. 5 is a schematic diagram illustrating an exploded structure of a battery cell according to one or more embodiments. The battery cell 20 refers to the smallest unit constituting the battery. As shown in fig. 5, the battery cell 20 includes an end cap 21, a case 22, an electrode assembly 23, and other functional components.
The end cap 21 refers to a member that is covered at the opening of the case 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 21 may be adapted to the shape of the housing 22 to fit the housing 22. Optionally, the end cover 21 may be made of a material (such as an aluminum alloy) with a certain hardness and strength, so that the end cover 21 is not easy to deform when being extruded and collided, so that the battery cell 20 can have higher structural strength, and the safety performance can be improved. The end cap 21 may be provided with a functional member such as an electrode terminal 21 a. The electrode terminal 21a may be used to be electrically connected with the electrode assembly 23 for outputting or inputting electric power of the battery cell 20. In some embodiments, the end cap 21 may also be provided with a pressure relief mechanism for relieving the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The material of the end cap 21 may be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in the embodiment of the present application. In some embodiments, insulation may also be provided on the inside of the end cap 21, which may be used to isolate electrical connection components within the housing 22 from the end cap 21 to reduce the risk of short circuits. By way of example, the insulation may be plastic, rubber, or the like.
The case 22 is an assembly for cooperating with the end cap 21 to form an internal environment of the battery cell 20, wherein the formed internal environment may be used to accommodate the electrode assembly 23, the electrolyte, and other components. The case 22 and the end cap 21 may be separate members, and an opening may be provided in the case 22, and the interior of the battery cell 20 may be formed by covering the opening with the end cap 21 at the opening. It is also possible to integrate the end cap 21 and the housing 22, but specifically, the end cap 21 and the housing 22 may form a common connection surface before other components are put into the housing, and when it is necessary to encapsulate the inside of the housing 22, the end cap 21 is then put into place with the housing 22. The housing 22 may be of various shapes and sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. Specifically, the shape of the case 22 may be determined according to the specific shape and size of the electrode assembly 23. The material of the housing 22 may be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in the embodiment of the present application.
The electrode assembly 23 is a component in which electrochemical reactions occur in the battery cell 20. One or more electrode assemblies 23 may be contained within the housing 22. The electrode assembly 23 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is generally provided between the positive electrode sheet and the negative electrode sheet. The portions of the positive electrode sheet and the negative electrode sheet having the active material constitute the main body portion of the electrode assembly, and the portions of the positive electrode sheet and the negative electrode sheet having no active material constitute the tab 23a, respectively. The positive electrode tab and the negative electrode tab may be located at one end of the main body portion together or located at two ends of the main body portion respectively. During charge and discharge of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab 23a is connected to the electrode terminal to form a current loop.
In one embodiment, the electrode assembly includes a porous positive electrode sheet, which may be obtained by immersing the positive electrode sheet in the electrolyte as described in any of the above embodiments.
In some embodiments, a positive electrode tab includes a current collector and a positive electrode active layer disposed on the current collector.
The positive electrode active layer includes a positive electrode active material, which may include at least one of the following materials: olivine structured lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material may be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (e.g., liCoO) 2 ) Lithium nickel oxide (e.g. LiNiO) 2 ) Lithium manganese oxide (e.g. LiMnO 2 、LiMn 2 O 4 ) Lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., liNi) 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM) 333 ）、LiNi 0.5 Co 0.2 Mn 0.3 O 2 (also referred to as NCM) 523 ）、LiNi 0.5 Co 0.25 Mn 0.25 O 2 (also referred to as NCM) 211 ）、LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also referred to as NCM) 622 ）、LiNi 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM) 811 ) Lithium nickel cobalt aluminum oxide (e.g. LiNi 0.85 Co 0.15 Al 0.05 O 2 ) And at least one of its modified compounds and the like. Examples of olivine structured lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (e.g., liFePO 4 (also abbreviated as LFP)), composite material of lithium iron phosphate and carbon, and manganese lithium phosphate (such as LiMnPO) 4 ) Composite material of lithium manganese phosphate and carbonAt least one of lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.
In some embodiments, the positive electrode active layer further contains an organic compound additive, a conductive agent, a binder, and the like. The specific structure is described in detail above and will not be repeated here.
In some embodiments, a negative electrode tab includes a current collector and a negative active layer disposed on the current collector.
The anode active layer includes an anode active material including, but not limited to, carbon-based anode materials, silicon-based anode materials, tin-based anode materials, lithium titanate anode materials, lithium metal anode materials, and the like; including in particular, but not limited to, graphite materials, silicon carbon materials, graphite-silicon oxide materials, nano-silicon materials, silicon oxide materials, and tin-based materials; more specifically natural graphite, artificial graphite, mesocarbon microbeads (MCMB), hard carbon, soft carbon, silicon-carbon composite, li-Sn alloy, li-Sn-O alloy, sn, snO, snO 2 Lithiated TiO of spinel structure 2 -Li 4 Ti 5 O 12 One or more of Li-Al alloys.
In some embodiments, the anode active layer may further include a binder, a conductive agent, and other optional adjuvants. As an example, the conductive agent may be one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, super P (SP), graphene, and carbon nanofibers. As an example, the binder may be one or more of styrene-butadiene rubber (SBR), aqueous acrylic resin (water-based acrylic resin), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyacrylic acid (PAA), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB). Other optional adjuvants may be, by way of example, thickening and dispersing agents (e.g., sodium carboxymethylcellulose CMC-Na), PTC thermistor materials.
In some embodiments, the material of the isolating film may be at least one selected from glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The separator may be a single-layer film or a multilayer composite film, and is not particularly limited. When the separator is a multilayer composite film, the materials of the respective layers may be the same or different, and are not particularly limited.
In one embodiment, the electrolyte includes one or more of carbonate solvents, ether solvents.
Carbonates are typically small molecule cyclic or chain carbonates; including, but not limited to, one or more of ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, methylpropyl carbonate, dipropyl carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, fluorocarbonates; and at least one ester solvent selected from gamma-butyrolactone, dimethyl sulfite, ethyl acetate, methyl butyrate, ethyl butyrate, methyl propionate, ethyl propionate, propyl acetate and fluorocarboxylate.
The ether solvents include, but are not limited to, one or more of dimethyl ether, diethyl ether, tetrahydrofuran, methyltetrahydrofuran, ethylene oxide, 1, 3-dioxolane, fluoroether, DME (ethylene glycol dimethyl ether), DEE (ethylene glycol diethyl ether), DEGDME (diethylene glycol dimethyl ether), TRGDME (triethylene glycol dimethyl ether), TEGDME (tetraethylene glycol dimethyl ether), dipropyl ether, and dibutyl ether.
In other embodiments, the electrolyte may further include any one or a mixture of several of amine solvents, sulfone solvents and nitrile solvents. The amine solvent comprises at least one of N-methylacetamide, N-methylformamide, dimethylformamide and diethylformamide. The sulfone solvent comprises at least one of dimethyl sulfoxide, sulfolane, diphenyl sulfoxide, thionyl chloride and dipropyl sulfone. The nitrile solvent comprises at least one of acetonitrile, succinonitrile, adiponitrile and glutaronitrile. The electrolyte is preferentially resistant to high-voltage electrolyte, the acidity of the electrolyte is weakened under high voltage, the transmission of active ions can be facilitated, the side reaction on the surface of the electrode is obviously reduced, and the stability of the battery is improved.
In some embodiments, the electrolyte further includes an electrolyte salt, which may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethylsulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalato borate, lithium difluorooxalato phosphate, and lithium tetrafluorooxalato phosphate.
In some embodiments, the electrolyte further optionally includes an additive. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives capable of improving certain properties of the battery, such as additives that improve the overcharge performance of the battery, additives that improve the high or low temperature performance of the battery, and the like.
In some embodiments, the use of the electrochemical device of the present application is not particularly limited, and it may be used in any electronic device known in the art. The battery disclosed by the embodiment of the application can be used for electric equipment using the battery as a power supply or various energy storage systems using the battery as an energy storage element. That is, there is provided an electric device, which in some embodiments, the electric device of the present application can be used for, but is not limited to, notebook computers, pen-input computers, mobile computers, electronic book players, portable telephones, portable fax machines, portable copiers, portable printers, headsets, video recorders, liquid crystal televisions, hand-held cleaners, portable CD-players, mini-compact discs, transceivers, electronic notepads, calculators, memory cards, portable audio recorders, radios, standby power supplies, motors, automobiles, motorcycles, mopeds, bicycles, ships, spacecraft, lighting fixtures, toys, game consoles, clocks, electric tools, flashlights, cameras, household large-sized storage batteries, lithium ion capacitors, and the like.
The electric equipment can select a battery cell, a battery module or a battery pack according to the use requirement.
Referring to fig. 6, fig. 6 is a schematic structural diagram of a vehicle according to one or more embodiments. The vehicle 1000 may be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or a range-extended vehicle. The battery 100 is provided in the interior of the vehicle 1000, and the battery 100 may be provided at the bottom or the head or the tail of the vehicle 1000. The battery 100 may be used for power supply of the vehicle 1000, for example, the battery 100 may be used as an operating power source of the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, the controller 200 being configured to control the battery 100 to power the motor 300, for example, for operating power requirements during start-up, navigation, and travel of the vehicle 1000.
In some embodiments of the present application, battery 100 may not only serve as an operating power source for vehicle 1000, but may also serve as a driving power source for vehicle 1000, instead of or in part instead of fuel oil or natural gas, to provide driving power for vehicle 1000.
In the above embodiment, in the solution injection process and the standing process of the battery assembly procedure, the solid phase additive in the active coating is dissolved by the injected electrolyte, namely the electrolyte fills the position occupied by the solid phase additive, so that the contact area between the active substance and the electrolyte is greatly increased, the infiltration effect of the electrolyte on the electrode plate is improved, and the electrolyte infiltration effect of the thick electrode is particularly improved; the migration rate of active ions in the electrode material can be effectively improved, the polarization internal resistance is reduced, and the multiplying power performance of the pole piece is improved. Therefore, through the design, the thickness of the positive electrode plate can be made thick, and the charging multiplying power can be considered on the basis of improving the energy density of the battery; ion transmission efficiency, immersion effect, etc.
The advantageous effects of the present application are further illustrated below with reference to examples.
In order to make the technical problems, technical schemes and beneficial effects solved by the embodiments of the present application more clear, the following will be described in further detail with reference to the embodiments and the accompanying drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. All other embodiments, which can be made by a person skilled in the art based on the embodiments of the application without any inventive effort, are intended to fall within the scope of the application.
Example 1
1) Preparation of cathode slurry
Positive electrode active material LiNi to be 97 g 0.8 Co 0.1 Mn 0.1 O 2 Mixing the conductive agent of 1 g and the binder of 2 g, adding the additive EC of 1 g, adding a proper amount of N-methyl pyrrolidone, stirring and dispersing.
2) Preparation of positive electrode plate
And (3) after the stirring of the prepared positive electrode slurry is finished, regulating the viscosity of the slurry to 35000-40000 mPa.s by using N-methyl pyrrolidone, then coating the positive electrode slurry on an aluminum foil by using coating equipment, and after the coating is finished, carrying out vacuum drying, cold pressing, cutting and preparing the positive electrode plate.
3) Buckling assembly
The positive pole piece is punched into a round pole piece with the diameter of 14 mm, and is assembled, buckled and kept stand for 24 hours for later use.
Examples 2 to 6
The difference from example 1 is the kind and amount of the additive, and the details are shown in Table 1.
Comparative example 1
The difference from example 1 is that no additional additives were added, see in particular table 1.
Pole piece and battery performance test
(1) Pole piece porosity test
The test is carried out with reference to the standard GB/T24586-2009. The method comprises the specific process that > 20 wafers with good appearance and no powder falling at the edge are selected by forceps and are filled into a sample cup. Recording the number of sheets, calculating the apparent volume, placing a sample cup filled with a sample in a true density tester, sealing a test system, introducing helium according to a program, detecting the pressure of the gas in a sample chamber and an expansion chamber, and calculating the true volume according to Bohr's law (PV=nRT), thereby obtaining the porosity of the sample to be tested. Wherein the porosity result output by the pole piece sample is not deducted from the base material.
(2) Testing of the liquid absorption Rate of Pole pieces
The imbibition rate is the most direct parameter for qualitatively characterizing the wettability of the electrolyte to the polar plate and is also the basic parameter for the most reactive porosity change. The testing method is based on the capillary action principle, and comprises the specific processes that electrolyte with a certain height is sucked by a capillary tube, the capillary tube is contacted with a dry pole piece, the time from the beginning of the falling of the electrolyte liquid level to the complete absorption of the electrolyte by the pole piece is measured, and then the calculation is carried out according to the following formula:
Imbibition rate = (capillary bottom area electrolyte height electrolyte density)/time.
(3) Testing of capacity utilization
Capacity exertion rate, the present application is defined as the ratio of the discharge capacity at the current discharge rate to the discharge capacity at 0.04C discharge rate. Specifically, taking a 1C discharge rate as an example, the capacity utilization rate is a ratio of 1C discharge capacity to 0.04C discharge capacity, and the capacity utilization rate calculation method of other rates is consistent with this.
(4) Capacity exertion test
Standing the battery at 25 ℃ for 30 min, and charging to 4.2V at a constant current of 0.04C;
standing for 1 hour at 25 ℃, and discharging at a constant current of 0.04 and C to 3V;
standing for 1 hour at 25 ℃, and charging to 4.2V under constant current of 0.04 and C;
standing for 1 hour at 25 ℃, and discharging the mixture to 3V under constant current of 1C;
standing for 1 hour at 25 ℃, and charging to 4.2V under constant current of 0.04 and C;
standing for 1 hour at 25 ℃, and discharging 3C to 3V under constant current;
standing for 1 hour at 25 ℃, and charging to 4.2V under constant current of 0.04 and C;
standing at 25 ℃ for 1 hour, and discharging 5C to 3V; standing at 25deg.C for 1 hr.
Table 1 tables of Condition parameters and test parameters for various examples
From the table above, it can be seen that: compared with comparative example 1, examples 1-6 of porous thick positive electrode plates prepared by the method provided by the application show that the porosity of the electrode plates of the examples is superior to that of the comparative example through porosity comparison, because the used additives are dissolved in electrolyte after the battery is injected, the in-situ pore-forming method can play a role in improving the porosity of the electrode plates to different degrees according to different pore-forming agent ratios (the porosity of the electrode plates can be improved by 4% -43.9%). In addition, the additive contained in the pole piece is easy to dissolve in the electrolyte, so that the liquid absorption rate of the pole piece is obviously improved, and the wettability of the pole piece and the electrolyte is also improved to a certain extent. The prepared lithium ion battery has the advantages of good multiplying power performance and balanced energy density.
The foregoing description is only of embodiments of the present application, and is not intended to limit the scope of the application, and all equivalent structures or equivalent processes using the descriptions and the drawings of the present application or directly or indirectly applied to other related technical fields are included in the scope of the present application.

Claims (16)

1. A positive electrode sheet, characterized by comprising:
a base layer;
and an active layer on the base layer, the active layer including a positive electrode active material and an organic compound-based additive, the organic compound-based additive being soluble in an electrolyte.
2. The positive electrode sheet according to claim 1, wherein the boiling point of the organic compound-based additive is greater than 150 ℃, and the melting point of the organic compound-based additive is greater than 30 ℃.
3. The positive electrode sheet according to claim 1 or 2, wherein the organic compound-based additive is soluble in a polar organic solvent.
4. The positive electrode sheet according to claim 3, wherein the polar organic solvent comprises one or more of N-methylpyrrolidone, N-dimethylformamide, N-diethylformamide, dimethylsulfoxide, pyridine and tetrahydrofuran.
5. The positive electrode sheet according to any one of claims 1 to 2, 4, wherein the organic compound-based additive comprises a solvent for an electrolyte and/or an additive for an electrolyte.
6. The positive electrode sheet according to claim 5, wherein the organic compound-based additive comprises one or more of ethylene carbonate and 1, 3-propane sultone.
7. The positive electrode sheet according to any one of claims 1 to 2, 4, 6, wherein the electrolyte comprises one or more of a carbonate-based solvent and an ether-based solvent.
8. The positive electrode sheet according to any one of claims 1 to 2, 4, 6, wherein the active layer has a thickness of 80 to 200 μm.
9. The positive electrode sheet according to claim 8, wherein the active layer has a thickness of 120-165 μm.
10. The positive electrode sheet according to any one of claims 1 to 2, 4, and 6, wherein the organic compound additive accounts for 0.2 to 1% by weight of the active layer.
11. The positive electrode sheet according to any one of claims 1 to 2, 4, 6, wherein the active layer further comprises a conductive agent and a binder;
the conductive agent comprises one or more of conductive carbon black, conductive graphite, carbon fiber, carbon nanotube, graphene, ketjen black and acetylene black;
The binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, acrylic ester and polyurethane.
12. The preparation method of the positive electrode plate is characterized by comprising the following steps:
mixing an anode active material, an organic compound additive and a solvent to obtain anode slurry;
coating the positive electrode slurry on a base layer, and drying to obtain a positive electrode plate; wherein, the organic compound additive of the positive electrode plate can be dissolved in electrolyte.
13. The method for preparing a positive electrode sheet according to claim 12, wherein the mass ratio of the positive electrode active material to the organic compound additive is 97:1 to 97:5.
14. A battery comprising a porous positive electrode sheet, wherein the porous positive electrode sheet is obtained by immersing the positive electrode sheet in electrolyte according to any one of claims 1 to 11; or the positive electrode sheet prepared by the method for preparing the positive electrode sheet according to claim 12 or 13 is immersed in the electrolyte.
15. The battery of claim 14, wherein the porous positive electrode sheet has a porosity of 20% -35%.
16. A powered device comprising a battery as claimed in claim 14 or 15.
CN202310876212.5A 2023-07-18 2023-07-18 Positive electrode plate, preparation method of positive electrode plate, battery and electric equipment Pending CN116646470A (en)

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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111640946A (en) * 2020-06-29 2020-09-08 天津市捷威动力工业有限公司 Infiltration improving additive, pole piece and infiltration method thereof, battery and preparation method thereof
CN113328098A (en) * 2021-07-12 2021-08-31 珠海冠宇电池股份有限公司 Negative plate and lithium ion battery comprising same
CN113346141A (en) * 2021-06-01 2021-09-03 清华大学 Amino acid slow-release composite carbon skeleton for lithium metal and preparation method thereof
US20210351395A1 (en) * 2018-09-28 2021-11-11 Ningbo Zhiliang New Energy Co., Ltd. Cathode additive and preparation method therefor, cathode electrode and preparation method therefor, and lithium ion battery
CN114188541A (en) * 2021-12-09 2022-03-15 河北省科学院能源研究所 Positive electrode plate of lithium ion battery and preparation method thereof
CN114204027A (en) * 2021-11-26 2022-03-18 华中科技大学 Lithium ion battery positive pole piece, preparation method thereof and lithium ion battery
CN114400301A (en) * 2022-03-09 2022-04-26 中南大学 High-performance thick pole piece of lithium ion battery and preparation method thereof
CN115911597A (en) * 2021-09-24 2023-04-04 比亚迪股份有限公司 Lithium ion battery electrode, preparation method thereof and lithium ion battery
CN116111044A (en) * 2023-04-11 2023-05-12 宁德新能源科技有限公司 Positive electrode sheet, secondary battery, and electronic device
CN116111042A (en) * 2023-04-11 2023-05-12 宁德新能源科技有限公司 Positive electrode sheet, secondary battery, and electronic device

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210351395A1 (en) * 2018-09-28 2021-11-11 Ningbo Zhiliang New Energy Co., Ltd. Cathode additive and preparation method therefor, cathode electrode and preparation method therefor, and lithium ion battery
CN111640946A (en) * 2020-06-29 2020-09-08 天津市捷威动力工业有限公司 Infiltration improving additive, pole piece and infiltration method thereof, battery and preparation method thereof
CN113346141A (en) * 2021-06-01 2021-09-03 清华大学 Amino acid slow-release composite carbon skeleton for lithium metal and preparation method thereof
CN113328098A (en) * 2021-07-12 2021-08-31 珠海冠宇电池股份有限公司 Negative plate and lithium ion battery comprising same
CN115911597A (en) * 2021-09-24 2023-04-04 比亚迪股份有限公司 Lithium ion battery electrode, preparation method thereof and lithium ion battery
CN114204027A (en) * 2021-11-26 2022-03-18 华中科技大学 Lithium ion battery positive pole piece, preparation method thereof and lithium ion battery
CN114188541A (en) * 2021-12-09 2022-03-15 河北省科学院能源研究所 Positive electrode plate of lithium ion battery and preparation method thereof
CN114400301A (en) * 2022-03-09 2022-04-26 中南大学 High-performance thick pole piece of lithium ion battery and preparation method thereof
CN116111044A (en) * 2023-04-11 2023-05-12 宁德新能源科技有限公司 Positive electrode sheet, secondary battery, and electronic device
CN116111042A (en) * 2023-04-11 2023-05-12 宁德新能源科技有限公司 Positive electrode sheet, secondary battery, and electronic device

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