CN111180730A - Rapid charging and discharging graphene power lithium battery and preparation method thereof - Google Patents
Rapid charging and discharging graphene power lithium battery and preparation method thereof Download PDFInfo
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- CN111180730A CN111180730A CN201911414602.0A CN201911414602A CN111180730A CN 111180730 A CN111180730 A CN 111180730A CN 201911414602 A CN201911414602 A CN 201911414602A CN 111180730 A CN111180730 A CN 111180730A
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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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
- H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/61—Types of temperature control
- H01M10/613—Cooling or keeping cold
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/65—Means for temperature control structurally associated with the cells
- H01M10/654—Means for temperature control structurally associated with the cells located inside the innermost case of the cells, e.g. mandrels, electrodes or electrolytes
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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
- H01M4/64—Carriers or collectors
- H01M4/70—Carriers or collectors characterised by shape or form
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- 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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- 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
Abstract
The invention discloses a fast charge-discharge graphene power lithium battery and a preparation method thereof, wherein the battery comprises: the battery comprises a battery shell and a battery core contained in the battery shell, wherein the battery core comprises a positive pole piece, a negative pole piece and a diaphragm, the positive pole piece comprises a positive current collector and positive material coatings respectively coated on two side surfaces of the positive current collector, the negative pole piece comprises a negative current collector and negative material coatings respectively coated on two side surfaces of the negative current collector, a conductive coating and a ceramic membrane are coated between the positive current collector and the positive material coating, a conductive coating and a ceramic membrane are coated between the negative current collector and the negative material coating, and the conductive coating is a CNT \ graphene coating; coating the positive active material in the positive conductive agent in the positive material coating and the negative active material in the negative conductive agent in the negative material coating by using the graphene suspension respectively; the positive and negative current collectors include a plurality of through holes arranged in a matrix shape and penetrating the upper and lower surfaces of the substrate.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a graphene power lithium ion battery and a preparation method thereof.
Background
The increasing exhaustion of traditional fossil energy sources and the environmental problems associated with the burning of fossil fuels are attracting attention. Therefore, the demand for developing an efficient, clean and environmentally friendly energy source is more and more urgent. In a traditional energy storage system, a lithium ion battery has the advantages of high stability, long cycle life, high voltage, certain flexibility, high safety, no memory characteristic and the like, and is widely applied to the field of small batteries such as mobile phones, computers, electric vehicles and the like.
However, this phenomenon is particularly significant in rapid charge and discharge, since lithium ion batteries generate heat when subjected to external load by overcoming internal resistance (internal resistance). If the heat cannot be dissipated in time, the heat generated in a short period can damage the internal structure of the battery cell to cause safety problems, so that the application of the battery cell is severely limited.
In the prior art, researchers mainly improve the phenomenon from two aspects of raw materials and cell structure design. In the aspect of raw materials, researchers mainly reduce internal resistance by means of adding a conductive agent, adopting an electrolyte with high conductivity, a diaphragm with high porosity and the like, and further improve the rapid charge-discharge performance of the battery. In the aspect of the structural design of the battery core, researchers mainly adopt an optimized tab structure to reduce internal resistance, and the rapid charge and discharge performance of the battery is improved to a certain extent.
As disclosed in chinese patent application publication CN103500844A, a cylindrical multi-polar ear lithium ion battery and a method for manufacturing the same, the lithium ion battery includes: a cylindrical housing; the anode cover plate and the cathode cover plate are provided with a convex platform extending towards the inside of the cylindrical shell; the electric core winding body is positioned in the cylindrical shell and formed by winding a positive plate, a diaphragm and a negative plate, and a plurality of tabs are arranged on the positive plate and the negative plate; and an electrolyte filled in the cylindrical case; wherein, a plurality of tabs on the negative plate extend to the center of the electric core winding body and are connected on the protruding platform. However, the lithium ion battery disclosed in this patent application adopts a mode of directly welding a plurality of tabs on the protruding platform, and this method is prone to cause cold joint and foil damage when welding the plurality of tabs.
For example, chinese patent application publication CN202549967U discloses a connection method of multiple tabs and cover plate of a lithium ion power battery, which is to weld a plurality of tabs led out from two ends of a battery cell on a tab with a slightly longer length, and weld the tab with the slightly longer length on the cover plate or a connection piece of the cover plate. However, the lithium ion battery disclosed in the patent application is obtained by welding a short tab to a long tab, and so on, and then welding the short tab to a cover plate or a cover plate connecting piece, which is difficult to realize when the number of tabs is large.
Therefore, although the prior art improves the rapid charging and discharging performance of the lithium power battery to a certain extent, the prior art has the disadvantages of low production efficiency, poor product consistency, difficult automatic production and no fundamental solution to the problems of heat generation and safety of the battery.
Therefore, in order to solve the above phenomena, the problem to be solved in the industry is urgently needed to provide a fast charging and discharging graphene power lithium battery with low heat production, fast heat dissipation and high safety performance and a preparation method thereof.
Disclosure of Invention
The first purpose of the invention is to provide a fast charge-discharge graphene power lithium battery, which can improve the problems of heat generation and heat dissipation during fast charge-discharge of the battery, and further improve the safety performance of the battery in the use process.
The invention provides a fast charge-discharge graphene power lithium battery, which comprises: the battery comprises a battery shell and a battery core contained in the battery shell, wherein the battery core comprises a positive pole piece, a negative pole piece and a diaphragm arranged between the positive pole piece and the negative pole piece, the positive pole piece comprises a positive current collector and positive material coatings coated on two side faces of the positive current collector respectively, and the negative pole piece comprises a negative current collector and negative material coatings coated on two side faces of the negative current collector respectively. The conductive coating and the ceramic membrane are coated between the anode current collector and the anode material coating, and the conductive coating and the ceramic membrane are coated between the cathode current collector and the cathode material coating, wherein the conductive coating is a CNT \ graphene coating; coating the positive active material in the positive conductive agent in the positive material coating and the negative active material in the negative conductive agent in the negative material coating by using the graphene suspension respectively; the positive current collector and the negative current collector comprise a plurality of through holes which are arranged in a matrix shape and penetrate through the upper surface and the lower surface of the base material.
The preparation method of the graphene suspension comprises the steps of grinding graphite oxide to prepare a suspension with the concentration of 2-4 mg/ml, carrying out ultrasonic treatment for 30 minutes, carrying out centrifugal treatment on the suspension for 15-20 minutes, and removing impurities in the suspension to obtain the graphene suspension.
In the invention, the positive pole piece comprises a nanoparticle positive pole material, a positive pole binder, a positive pole solvent and a positive pole conductive agent. The negative pole piece comprises a nano-particle negative pole material, a negative pole binder, a negative pole solvent and a negative pole conductive agent.
The nano-particle positive electrode material, the positive electrode conductive agent, the positive electrode binder and the positive electrode solvent in the positive electrode piece are mixed and prepared according to the mass ratio of 100-150: 2-6: 3-7: 85-96. The nano-particle negative electrode material, the negative electrode conductive agent, the negative electrode binder and the negative electrode solvent in the negative electrode plate are mixed and prepared according to the mass ratio of 85-98: 1-3: 1-10: 100-150.
Wherein the nano-particle cathode material is at least one of the following materials: lithium iron phosphate, lithium manganate, lithium cobaltate, or lithium nickel cobalt manganate. The nano-particle negative electrode material is at least one of the following materials: graphite, carbon nanotubes, needle coke, petroleum coke, carbon fibers, or non-graphitizing mesophase carbon microspheres.
Preferably, the nanoparticle positive electrode material comprises two ternary materials, one is a ternary material comprising nickel, cobalt and lithium, and the other is a ternary material comprising nickel, cobalt and manganese, wherein in the first ternary material, the ratio of nickel, cobalt and manganese is 8:1:1, 6: 2: 2. 5:2:3 and 1:1:1, in another ternary material, the ratio of nickel, cobalt and aluminium is 9:0.7: 0.3.
Optionally, the positive binder is one or more of polyvinylidene fluoride, polytetrafluoroethylene, sodium carboxymethylcellulose and styrene butadiene rubber, and the negative binder is one or more of polyvinylidene fluoride, polytetrafluoroethylene, sodium carboxymethylcellulose and styrene butadiene rubber. The positive electrode binder and the negative electrode binder can be the same binder or different binders.
Wherein, the anode solvent is one or more of deionized water, distilled water, industrial alcohol, absolute ethyl alcohol, acetone and NMP, and the cathode solvent is one or more of deionized water, distilled water, industrial alcohol, absolute ethyl alcohol, acetone and NMP. The positive electrode solvent and the negative electrode solvent can be the same solvent or different solvents.
The positive electrode conductive agent includes: 97-99 parts of positive active material, 0.2-0.4 part of Ketjen black and 0.2-0.4 part of carbon nano tube. The negative electrode conductive agent includes: 97-99 parts of negative active material, 0.2-0.4 part of nano-grade superfine carbon powder and 0.2-0.4 part of carbon nano tube.
Wherein the positive electrode active material or the negative electrode active material is one or a mixture of at least two of carbon black, conductive graphite, ketjen black, acetylene black or carbon nanofibers.
Optionally, the tail of the battery cell is terminated by copper foil, the length of the copper foil is set to be 1.5-2 times of the circumference of the battery cell, and the length of the copper foil is set to be 6-12 micrometers.
Optionally, the thickness of the conductive coating is set to be 1-5 microns, and the thickness of the ceramic film is set to be 2-5 microns.
Optionally, the positive current collector and the negative current collector are concave-convex three-dimensional structure through-hole foils or sponge foam structure through-hole copper foils with the thickness of 6-12 microns; the through holes comprise a first type of through holes and a second type of through holes which are arranged in a staggered mode, the first type of through holes are formed by punching from the first surface to the second surface of the base material, the second type of through holes are formed by punching from the second surface to the first surface of the base material, the aperture of the first type of through holes is 0.25-0.35 mm, and the aperture of the second type of through holes is set to be 0.1-0.2 mm.
The second purpose of the present invention is to provide a method for preparing a fast charging and discharging graphene power lithium battery, which comprises the following steps: (1) coating the positive active material by using graphene suspension, mixing 97-99 parts of the coated positive active material, 0.2-0.4 part of Ketjen black and 0.2-0.4 part of carbon nano tube, mixing the mixed material with a nanoparticle positive material, a positive binder and a positive solvent, and carrying out vacuum emulsification for 1-3 hours to obtain the positive material of the fast charging and discharging graphene power lithium battery; (2) coating the negative active material by using graphene suspension, mixing 97-99 parts of the coated negative active material, 0.2-0.4 part of nanoscale ultrafine carbon powder and 0.2-0.4 part of carbon nano tube, mixing the mixed material with a nanoparticle negative material, a negative binder and a negative solvent, and performing vacuum emulsification for 1-3 hours to obtain the negative material of the fast charge-discharge graphene power lithium battery; (3) sequentially coating a conductive coating, a positive material and a ceramic membrane on two side surfaces of a positive current collector to form a positive pole piece, sequentially coating a conductive coating, a negative material and a ceramic membrane on two side surfaces of a negative current collector to form a negative pole piece, and reserving the positions of pole lugs at the edge positions of the positive current collector and the negative current collector respectively when coating; (4) respectively compressing the coated positive pole piece and the coated negative pole piece at 60-130 ℃, and cutting into unit parts according to a set value; and (5) winding the unit parts obtained in the step (4) by using diaphragm paper to form a winding core, and adopting copper foil ending for the winding core.
Optionally, in step (1), the method comprises: (1-1) placing the positive active material into the graphene suspension, and stirring for 1-4 hours in a vacuum state to form a mixture; (1-2) placing the mixture prepared in the step (1-1) in a spray dryer, and stirring for 1-4 hours at 40-80 ℃ to prepare a coated positive active material; and (1-3) mixing 97-99 parts of the positive active material prepared in the step (1-2) with 0.2-0.4 part of Ketjen black and 0.2-0.4 part of carbon nano tube, mixing the mixed material with a nanoparticle positive material, a positive binder and a positive solvent, and carrying out vacuum emulsification for 1-3 hours to prepare the positive material of the graphene power lithium battery capable of being rapidly charged and discharged.
Optionally, in step (2), the method includes: (2-1) placing a negative electrode active material in the graphene suspension, and stirring for 1-4 hours in a vacuum state to form a mixture; (2-2) placing the mixture prepared in the step (2-1) in a spray dryer, and stirring for 1-4 hours at 40-80 ℃ to prepare a coated negative active material; and (2-3) mixing 97-99 parts of the negative active material prepared in the step (2-3) with 0.2-0.4 part of nano-scale ultrafine carbon powder and 0.2-0.4 part of carbon nano tube, mixing the mixed material with a nano-particle negative material, a negative binder and a negative solvent, and carrying out vacuum emulsification for 1-3 hours to prepare the negative material of the graphene power lithium battery capable of being charged and discharged rapidly.
In the step (1), after the coated positive active material is mixed with other materials and dried, the mixed material is in a three-dimensional structure particle, so that a foundation is laid for forming an ultrafast electronic network on the surface of the positive electrode, and the positive electrode plate is enabled to have a three-dimensional nano-layer electronic ultrafast conduction structure. Likewise, in step (2), the negative electrode plate is also constructed in a structure of nano-oriented channels.
Alternatively, in the step (1-1) and the step (2-1), the stirring speed is set to 50 to 80 rpm.
Optionally, in the step (3), setting a blank area with a width of 20-24 mm on two side edges of two surfaces to be coated of the positive current collector respectively, spraying a conductive coating with a thickness of 1-5 microns on the non-blank area of the surface to be coated of the positive current collector, drying, and spraying a positive material on the non-blank area of the surface of the two coated conductive coatings of the positive current collector respectively; (3-2) respectively coating ceramic membranes with the thickness of 2-5 microns on the blank areas of the surfaces of the two coated positive electrode materials of the positive electrode current collector to prepare a positive electrode piece, and reserving the position of a positive electrode lug at the edge position of the positive electrode current collector; (3-3) respectively arranging a blank area with the width of 20-24 mm on two side edges of two surfaces to be coated of the negative current collector, spraying a conductive coating with the thickness of 1-5 microns on the non-blank area of the surface to be coated of the negative current collector, drying, and spraying a negative material on the non-blank area of the surface of the two coated conductive coatings of the negative current collector; and (3-4) respectively coating ceramic membranes with the thickness of 2-5 microns on the blank areas of the surfaces of the two coated negative materials of the negative current collector to manufacture a negative pole piece, and reserving the positions of negative pole lugs at the edge position of the negative current collector.
Preferably, both sides of the positive current collector substrate are respectively left white for 22 +/-1 mm without coating during coating, a coating area is coated and dried by adopting CNT \ graphene colloidal fluid, the thickness is controlled to be 1-5 micrometers, prepared slurry, namely a positive material or a negative material, is coated again, and finally, a ceramic membrane is coated on the white area again, wherein the ceramic membrane with the width of 5-10 millimeters is adopted at the edge of the substrate, and the coating thickness is controlled to be 2-5 micrometers, so that the problem of micro short circuit can be effectively solved. Optionally, the mass ratio of the CNT to the graphene is 5-1: 1 to 5.
In the coating process, the spraying method is adopted to ensure that the through holes, namely the through holes, can be effectively coated.
Optionally, in step (4), the compaction pressure is calculated according to the material compaction ratio, different parameters of different equipment can be set and adjusted according to actual conditions, and 3 times of high-temperature compaction method is adopted.
Optionally, in the copper foil ending process in the step (5), the size of the reserved copper foil is changed along with the change of the model size of the winding core, the thickness of the copper foil is 6-12 mm, and the length of the copper foil is 1.5-2 times of the circumference of the winding core.
Optionally, the method further comprises: (6) respectively carrying out prewelding treatment on a positive electrode lug and a negative electrode lug at two ends of the coiled core which finishes ending, then welding a positive electrode overflowing sheet on the positive electrode lug which finishes prewelding, welding a negative electrode overflowing sheet on the negative electrode lug which finishes prewelding, then respectively welding the positive electrode overflowing sheet and the negative electrode overflowing sheet on a cover plate to prepare a battery cell, and finally putting the battery cell into a shell; (7) performing cover plate welding, baking and liquid injection on the battery cell to complete the assembly of the battery cell; and (8) carrying out formation and grading on the assembled battery core, and after activation, preparing the fast charging and discharging graphene power lithium battery.
Optionally, the diaphragm paper used in the step (6) is an adhesive diaphragm with a three-layer film coating thickness of 1-4 microns.
The beneficial effects of the invention are as follows: (1) the fast charge-discharge graphene power lithium battery can realize fast charge and discharge, has the advantages of low heat production, fast heat dissipation and high safety performance, and is very suitable for the field of fast charge-discharge power batteries; (2) the positive active substance and the negative active substance are respectively coated with graphene, and the conductive agent adopts graphene suspension prepared by an emulsification process during proportioning, so that the positive active substance is in a three-dimensional nano-layer electronic ultra-fast conduction structure, the ultra-strong conductivity and ultra-low resistivity of the graphene are exerted, the ultra-high rate charging is ensured to be realized when charging is carried out, 80C is reached, the negative active substance forms a nano directional channel, the ultra-fast and ordered conduction of lithium ions is ensured, and the ultra-high rate discharging can be realized, and 120C is reached; (3) the battery winding core adopts a copper foil ending mode, so that the heat dissipation performance of the battery core can be increased, and the radial temperature difference inside the battery core is reduced; (4) the pre-welding step of the tab can effectively solve the problems of insufficient welding, falling, over-welding, tab damage and the like of the tab, and realizes the automatic production of the full-tab battery; (5) the preparation method has simple procedures, reduces the procedures by 60 percent compared with the traditional preparation method, and greatly improves the production efficiency; (6) the preparation method provided by the invention can be grafted with any traditional lithium battery equipment for use, and is suitable for soft packages and square lithium ion power batteries.
Drawings
Fig. 1 is a schematic flow diagram of a preparation method of a fast charge-discharge graphene power lithium battery according to the present invention.
Fig. 2 is an SEM image of the negative electrode current collector of the present invention.
Fig. 3 is a schematic view of a white space of the positive electrode current collector of the present invention.
Fig. 4 is a schematic structural view of a pre-welded winding core of the present invention.
Fig. 5 is a schematic structural diagram of a battery cell casing according to the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
As a non-limiting embodiment, the method for manufacturing a fast charge and discharge graphene-based power lithium battery according to the present invention is as shown in fig. 1, and first, in step S1, a positive electrode active material is coated with a graphene suspension, 98 parts of coated conductive graphite, 0.4 part of ketjen black, and 0.4 part of carbon nanotubes are mixed, the mixed material is mixed with a nanoparticle positive electrode material, a positive electrode binder, and a positive electrode solvent, and vacuum emulsification is performed for 1 to 3 hours, thereby manufacturing a positive electrode material of a fast charge and discharge graphene-based power lithium battery.
Specifically, in step S1, the conductive graphite is placed in the graphene suspension, and stirred for 3 hours in a vacuum state to form a mixture, and then the obtained mixture is placed in a spray dryer, and stirred for 3 hours at 60 degrees celsius to obtain the coated conductive graphite. And then, mixing 98 parts of coated conductive graphite with 0.4 part of Ketjen black and 0.4 part of carbon nano tube to obtain a coated mixed material, mixing the lithium iron phosphate nano particles, the mixed material, polyvinylidene fluoride and alcohol according to the proportion of 120:4:5:90, and performing vacuum emulsification for 2 hours to obtain the positive electrode material of the graphene power lithium battery capable of being rapidly charged and discharged.
Then, in step S2, coating conductive graphite with a graphene suspension, mixing 97-99 parts of coated conductive graphite, 0.2-0.4 part of nanoscale ultrafine carbon powder, and 0.2-0.4 part of carbon nanotubes, mixing the mixed material with a nanoparticle negative electrode material, a negative electrode binder, and a negative electrode solvent, and performing vacuum emulsification for 2 hours to obtain the negative electrode material of the fast charging and discharging graphene power lithium battery.
Specifically, in step S2, the conductive graphite is placed in the graphene suspension and stirred for 4 hours in a vacuum state to form a mixture, and then the obtained mixture is placed in a spray dryer and stirred for 3 hours at 70 degrees celsius to obtain the coated conductive graphite. And finally, mixing 99 parts of conductive graphite, 0.2-0.4 part of nanoscale ultrafine carbon powder and 0.2-0.4 part of carbon nano tubes to obtain a coated mixed material, mixing the graphite, the mixed material, polyvinylidene fluoride and a solvent NMP according to a ratio of 90:2:4:100, and performing vacuum emulsification for 2 hours to obtain the negative electrode material of the graphene power lithium battery capable of being rapidly charged and discharged.
In step S3, a positive electrode sheet is formed by sequentially coating a conductive coating, a positive electrode material, and a ceramic film on both sides of a positive electrode current collector, a negative electrode sheet is formed by sequentially coating a conductive coating, a negative electrode material, and a ceramic film on both sides of a negative electrode current collector, and the positions of tabs are reserved at the edge positions of the positive electrode current collector and the negative electrode current collector respectively when coating is performed.
In the present invention, the positive current collector and the negative current collector are copper foils with a thickness of 6 to 12 micrometers, taking the negative current collector as an example, as shown in fig. 2, the through holes include first-type through holes and second-type through holes which are arranged in a staggered manner, the first-type through holes are punched from the first surface to the second surface of the substrate, the second-type through holes are punched from the second surface to the first surface of the substrate, and the aperture of the first-type through holes is slightly larger than that of the second-type through holes.
In step S3, as shown in fig. 3, a blank area Q with a width of 20-24 mm is disposed on two side edges of the surface S to be coated of the positive current collector, and after a conductive coating with a thickness of 1-5 μm is sprayed on a non-blank area F of the surface S to be coated of the positive current collector and dried, positive electrode materials are respectively sprayed on the non-blank areas F of the two surfaces of the positive current collector, which are coated with the conductive coating. And then, coating ceramic membranes with the thickness of 2-5 microns on the blank areas Q of the surfaces of the two coated positive electrode materials of the positive electrode current collector to manufacture a positive electrode piece, and reserving the position of a positive electrode lug at the edge position of the positive electrode current collector.
And then, setting a 20-24 mm wide margin area on two side edges of two surfaces to be coated of the negative current collector, respectively, spraying a conductive coating with the thickness of 1-5 microns on the non-margin area of the surface to be coated of the negative current collector, drying, and respectively spraying a negative material on the non-margin area of the surface of the two surfaces coated with the conductive coating of the negative current collector. And then, coating ceramic membranes with the thickness of 2-5 microns on the blank areas of the two surfaces of the negative current collector coated with the negative materials to prepare a negative pole piece, and reserving the positions of negative pole lugs at the edge position of the negative current collector.
With reference to fig. 1, in step S4, the coated positive electrode plate and the coated negative electrode plate are respectively compressed at 60-130 ℃, and cut into unit parts according to the set values.
Subsequently, in step S5, the unit portion of step S4 is wound with separator paper to form a core, and a copper foil tail T is taken for the core (as shown in fig. 5). In this non-limiting embodiment, the length of the copper foil is set to be 1.5 to 2 times the circumference of the cell, and the copper foil is set to be 6 to 12 μm.
In this non-limiting embodiment, step S6 is also included. In this step, the prewelding treatment of the positive electrode tab E1 and the negative electrode tab E2 is performed on both ends of the completed roll core, and the roll core after the prewelding is completed is as shown in fig. 4. Then, welding a positive electrode overflowing sheet G1 at a positive electrode welding point K1 on the positive electrode tab E1 after the pre-welding is finished, welding a negative electrode overflowing sheet G2 at a negative electrode welding point K2 on the negative electrode tab E2 after the pre-welding is finished, then respectively welding the positive electrode overflowing sheet and the negative electrode overflowing sheet on a cover plate to manufacture a battery cell, and finally putting the battery cell into a shell (as shown in FIG. 5).
Subsequently, in step S7, the cell is subjected to cover welding, baking, and liquid injection, completing the assembly of the cell. Finally, in step S8, the assembled battery core is subjected to chemical conversion and capacity grading, and after activation, the graphene power lithium battery with rapid charge and discharge is manufactured.
Therefore, the graphene power lithium battery capable of being charged and discharged rapidly provided by the invention comprises: the battery comprises a battery shell and a battery cell accommodated in the battery shell, wherein the battery cell comprises a positive pole piece, a negative pole piece and a diaphragm arranged between the positive pole piece and the negative pole piece, the positive pole piece comprises a positive current collector and positive material coatings respectively coated on two side faces of the positive current collector, the negative pole piece comprises a negative current collector and negative material coatings respectively coated on two side faces of the negative current collector, a conductive coating and a ceramic membrane are coated between the positive current collector and the positive material coating, a conductive coating and a ceramic membrane are coated between the negative current collector and the negative material coating, and the conductive coating is a CNT \ graphene coating; coating the positive active material in the positive conductive agent in the positive material coating and the negative active material in the negative conductive agent in the negative material coating by using the graphene suspension respectively; the positive current collector and the negative current collector comprise a plurality of through holes which are arranged in a matrix shape and penetrate through the upper surface and the lower surface of the base material.
Although preferred embodiments of the present invention have been described in detail herein, it is to be understood that this invention is not limited to the precise construction and steps herein shown and described, and that other modifications and variations may be effected by one skilled in the art without departing from the spirit and scope of the invention. In addition, the parameters in the present invention may be appropriately selected within the range disclosed in the present invention depending on the specific use conditions.
Claims (10)
1. A fast charge-discharge graphene power lithium battery comprises: the battery comprises a battery shell and a battery core accommodated in the battery shell, wherein the battery core comprises a positive pole piece, a negative pole piece and a diaphragm arranged between the positive pole piece and the negative pole piece, the positive pole piece comprises a positive current collector and positive material coatings coated on two side faces of the positive current collector respectively, the negative pole piece comprises a negative current collector and negative material coatings coated on two side faces of the negative current collector respectively,
a conductive coating and a ceramic film are coated between the positive current collector and the positive material coating, and a conductive coating and a ceramic film are coated between the negative current collector and the negative material coating, wherein the conductive coating is a CNT \ graphene coating;
coating the positive active material in the positive conductive agent in the positive material coating and the negative active material in the negative conductive agent in the negative material coating by using graphene suspension respectively;
the positive current collector and the negative current collector comprise a plurality of through holes which are arranged in a matrix shape and penetrate through the upper surface and the lower surface of the base material.
2. The fast charge-discharge graphene power lithium battery as claimed in claim 1, wherein the tail of the cell is terminated with a copper foil, the length of the copper foil is set to be 1.5 to 2 times of the circumference of the cell, and the length of the copper foil is set to be 6 to 12 microns.
3. The fast charging and discharging graphene power lithium battery according to claim 1, wherein the thickness of the conductive coating is set to 1-5 microns, and the thickness of the ceramic film is set to 2-5 microns.
4. The preparation method of the fast charge-discharge graphene power lithium battery as claimed in claims 1 to 3, characterized by comprising the following steps:
(1) coating the positive active material by using graphene suspension, mixing 97-99 parts of the coated positive active material, 0.2-0.4 part of Ketjen black and 0.2-0.4 part of carbon nano tube, mixing the mixed material with a nanoparticle positive material, a positive binder and a positive solvent, and performing vacuum emulsification for 1-3 hours to obtain the positive material of the rapid charging and discharging graphene power lithium battery;
(2) coating the negative active material by using graphene suspension, mixing 97-99 parts of the coated negative active material, 0.2-0.4 part of nanoscale ultrafine carbon powder and 0.2-0.4 part of carbon nano tube, mixing the mixed material with a nanoparticle negative material, a negative binder and a negative solvent, and performing vacuum emulsification for 1-3 hours to obtain the negative material of the fast charge-discharge graphene power lithium battery;
(3) sequentially coating the conductive coating, the positive material and the ceramic membrane on two side surfaces of the positive current collector to form a positive pole piece, sequentially coating the conductive coating, the negative material and the ceramic membrane on two side surfaces of the negative current collector to form a negative pole piece, and reserving the positions of pole lugs at the edge positions of the positive current collector and the negative current collector respectively during coating;
(4) respectively compressing the coated positive pole piece and the coated negative pole piece at 60-130 ℃, and cutting into unit parts according to a set value; and
(5) and (3) winding the unit parts obtained in the step (4) by using diaphragm paper to form a winding core, and adopting copper foil ending for the winding core.
5. The method for preparing the fast charge-discharge graphene-based power lithium battery as claimed in claim 4, wherein the step (1) comprises:
(1-1) placing the positive active material in the graphene suspension, and stirring for 1-4 hours in a vacuum state to form a mixture;
(1-2) placing the mixture prepared in the step (1-1) in a spray dryer, and stirring for 1-4 hours at 40-80 ℃ to prepare the coated positive active material; and
(1-3) mixing 97-99 parts of the positive active material prepared in the step (1-2) with 0.2-0.4 part of Ketjen black and 0.2-0.4 part of carbon nano tube, mixing the mixed material with a nanoparticle positive material, a positive binder and a positive solvent, and performing vacuum emulsification for 1-3 hours to prepare the positive material of the fast charge-discharge graphene power lithium battery.
6. The method for preparing the fast charge-discharge graphene-based power lithium battery as claimed in claim 4, wherein the step (2) comprises:
(2-1) placing the negative active material in the graphene suspension, and stirring for 1-4 hours in a vacuum state to form a mixture;
(2-2) placing the mixture prepared in the step (2-1) in a spray dryer, and stirring for 1-4 hours at 40-80 ℃ to prepare the coated negative active material; and
(2-3) mixing 97-99 parts of the negative active material prepared in the step (2-3) with 0.2-0.4 part of nanoscale ultrafine carbon powder and 0.2-0.4 part of carbon nano tube, mixing the mixed material with a nanoparticle negative material, a negative binder and a negative solvent, and carrying out vacuum emulsification for 1-3 hours to prepare the negative material of the fast charge-discharge graphene power lithium battery.
7. The method for preparing a fast charge-discharge graphene-based power lithium battery according to claim 5, wherein the step (3) comprises:
(3-1) respectively arranging a blank area with the width of 20-24 mm on two side edges of two surfaces to be coated of the positive current collector, spraying the conductive coating with the thickness of 1-5 microns on the non-blank area of the surface to be coated of the positive current collector, drying, and spraying the positive material on the non-blank area of the surface of the two coated conductive coatings of the positive current collector;
(3-2) coating the ceramic membranes with the thickness of 2-5 microns on the blank areas of the surfaces of the two coated positive electrode materials of the positive electrode current collector respectively to prepare a positive electrode piece, and reserving the positions of positive electrode lugs at the edge position of the positive electrode current collector;
(3-3) respectively arranging a blank area with the width of 20-24 mm on two side edges of two surfaces to be coated of the negative current collector, spraying the conductive coating with the thickness of 1-5 microns on the non-blank area of the surface to be coated of the negative current collector, drying, and spraying the negative material on the non-blank area of the surface of the two conductive coatings coated of the negative current collector; and
(3-4) coating the ceramic membranes with the thickness of 2-5 microns in the blank areas on the surfaces of the two coated negative materials of the negative current collector to form the negative pole piece, and reserving the positions of negative pole lugs at the edge positions of the negative current collector.
8. The method for preparing the fast charge-discharge graphene-powered lithium battery as claimed in claim 4, wherein in the copper foil ending process in the step (5), the thickness of the copper foil is 6-12 mm, and the length of the copper foil is 1.5-2 times of the circumference of the winding core.
9. The method for preparing a fast charge-discharge graphene-powered lithium battery as claimed in claim 4, further comprising:
(6) respectively carrying out prewelding treatment on a positive electrode lug and a negative electrode lug at two ends of the coiled core which is finished to be terminated, then welding a positive electrode overflowing sheet on the positive electrode lug which is finished to be prewelded, welding a negative electrode overflowing sheet on the negative electrode lug which is finished to be prewelded, then respectively welding the positive electrode overflowing sheet and the negative electrode overflowing sheet on a cover plate to prepare a battery cell, and finally putting the battery cell into a shell;
(7) performing cover plate welding, baking and liquid injection on the battery cell to finish the assembly of the battery cell; and
(8) and forming and grading the assembled battery core, and preparing the quick charge-discharge graphene power lithium battery after activation.
10. The method for preparing the fast charge-discharge graphene-powered lithium battery as claimed in claim 9, wherein the separator paper used in the step (6) is an adhesive separator with a thickness of 1-4 μm of a three-layer film coating.
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| CN201911414602.0A CN111180730A (en) | 2019-12-31 | 2019-12-31 | Rapid charging and discharging graphene power lithium battery and preparation method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113690403A (en) * | 2021-08-25 | 2021-11-23 | 蜂巢能源科技有限公司 | Battery pole group, preparation method thereof and lithium ion battery |
| CN113948710A (en) * | 2021-10-22 | 2022-01-18 | 珠海冠宇电池股份有限公司 | Positive current collector, positive plate and lithium ion battery |
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2019
- 2019-12-31 CN CN201911414602.0A patent/CN111180730A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113690403A (en) * | 2021-08-25 | 2021-11-23 | 蜂巢能源科技有限公司 | Battery pole group, preparation method thereof and lithium ion battery |
| CN113690403B (en) * | 2021-08-25 | 2022-12-27 | 蜂巢能源科技有限公司 | Battery pole group, preparation method thereof and lithium ion battery |
| CN113948710A (en) * | 2021-10-22 | 2022-01-18 | 珠海冠宇电池股份有限公司 | Positive current collector, positive plate and lithium ion battery |
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