CN116417567A - Positive electrode plate, energy storage device and preparation method - Google Patents
Positive electrode plate, energy storage device and preparation method Download PDFInfo
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- CN116417567A CN116417567A CN202310681198.3A CN202310681198A CN116417567A CN 116417567 A CN116417567 A CN 116417567A CN 202310681198 A CN202310681198 A CN 202310681198A CN 116417567 A CN116417567 A CN 116417567A
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- 238000004146 energy storage Methods 0.000 title claims abstract description 62
- 238000002360 preparation method Methods 0.000 title claims abstract description 26
- 239000011247 coating layer Substances 0.000 claims abstract description 366
- 239000000835 fiber Substances 0.000 claims abstract description 151
- 238000000034 method Methods 0.000 claims abstract description 19
- 238000002347 injection Methods 0.000 claims description 54
- 239000007924 injection Substances 0.000 claims description 54
- 239000000463 material Substances 0.000 claims description 30
- 239000002002 slurry Substances 0.000 claims description 25
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 18
- 239000002033 PVDF binder Substances 0.000 claims description 14
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical group [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 claims description 14
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 14
- 239000011248 coating agent Substances 0.000 claims description 11
- 238000000576 coating method Methods 0.000 claims description 11
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- 238000003780 insertion Methods 0.000 description 9
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- 229910052751 metal Inorganic materials 0.000 description 8
- 239000002184 metal Substances 0.000 description 8
- ILXAVRFGLBYNEJ-UHFFFAOYSA-K lithium;manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[O-]P([O-])([O-])=O ILXAVRFGLBYNEJ-UHFFFAOYSA-K 0.000 description 7
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 6
- 239000011267 electrode slurry Substances 0.000 description 6
- 239000011268 mixed slurry Substances 0.000 description 6
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 5
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- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 4
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
- 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
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0404—Methods of deposition of the material by coating on electrode collectors
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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
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0411—Methods of deposition of the material by extrusion
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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
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0419—Methods of deposition of the material involving spraying
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—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
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
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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
Abstract
The invention discloses a positive pole piece, an energy storage device and a preparation method, wherein the positive pole piece comprises a current collector, a first coating layer, a second coating layer and an interface connection structure, wherein the first coating layer is arranged on the current collector in a lamination manner; the second coating layer is arranged on one side surface of the first coating layer, which is away from the current collector; the interface connection structure comprises conductive fibers, wherein one ends of the conductive fibers are inserted into one side surface of the first coating layer, which faces away from the current collector, and the other ends of the conductive fibers are inserted into one side surface of the second coating layer, which faces towards the first coating layer. The invention provides a method for improving the electrochemical performance of an energy storage device by improving the structural strength of a positive pole piece.
Description
Technical Field
The application relates to the technical field of energy storage, in particular to a positive plate, an energy storage device and a preparation method.
Background
In the preparation of the positive electrode plate, firstly, a main material is added into a stirrer for stirring and premixing to obtain a mixture, then, the mixture and an organic solvent are stirred and dispersed under a vacuum condition, then, the organic solvent is added for high-speed stirring and dispersing to obtain mixed slurry, the mixed slurry is sieved to remove large particles in the mixed slurry, so that the positive electrode slurry is obtained, finally, the positive electrode slurry is coated on a current collector to form a first coating layer, and after the first coating layer is sufficiently dried, another positive electrode slurry is coated on the first coating layer to form a second coating layer, so that the positive electrode plate is obtained.
In the related art, because the first coating layer and the second coating layer are in surface lamination connection with each other, the connection stability between the first coating layer and the second coating layer is weaker, so that the structural strength of the positive pole piece is poorer, meanwhile, the contact resistance between the first coating layer and the second coating layer is increased, and the exertion of the electrochemical performance of the energy storage device is further influenced.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides the positive electrode plate, the energy storage device and the preparation method, which can improve the structural strength of the positive electrode plate, thereby improving the exertion of the electrochemical performance of the energy storage device.
In order to solve the technical problem, in a first aspect, the present invention provides a positive electrode sheet, including:
a current collector;
a first coating layer stacked on the current collector;
the second coating layer is arranged on one side surface of the first coating layer, which is away from the current collector, in a stacked manner;
the interface connection structure comprises conductive fibers, wherein one ends of the conductive fibers are inserted into one side surface of the first coating layer, which faces away from the current collector, and the other ends of the conductive fibers are inserted into one side surface of the second coating layer, which faces towards the first coating layer.
Because the interface connection structure is arranged between the first coating layer and the second coating layer, one end of the conductive fiber in the interface connection structure is inserted into one side surface of the first coating layer, which is away from the current collector, and the other end of the conductive fiber is inserted into one side surface of the second coating layer, which faces the first coating layer, therefore, compared with the direct bonding connection of the first coating layer and the second coating layer, on the one hand, the interface resistance between the first coating layer and the second coating layer can be reduced by arranging the conductive fiber, and the two ends of the conductive fiber are respectively inserted into the first coating layer and the second coating layer, the connection between the first coating layer and the second coating layer can be realized by the conductive fiber, so that the connection stability between the first coating layer and the second coating layer is improved, and the structural strength of the positive electrode plate is further improved, and on the other hand, because the conductive fiber is made of chemical fiber, metal wire, carbon fiber or the like with conductive medium, the interface resistance between the first coating layer and the second coating layer can be reduced, so that the electrochemical performance of the energy storage device formed by the positive electrode plate is improved.
In a possible implementation manner of the first aspect, the first coating layer is a lithium manganese iron phosphate coating layer, and the second coating layer is a ternary material coating layer.
Since the voltage plateau of lithium manganese iron phosphate is 4.1V, which is much higher than the voltage plateau (3.4V) of lithium iron phosphate, the energy density of lithium manganese iron phosphate is higher than that of lithium iron phosphate, and therefore, the energy density of the energy storage device formed by the positive electrode plate can be improved by adopting the lithium manganese iron phosphate coating layer.
In a possible implementation manner of the first aspect, the thickness of the first coating layer is 30 μm-50 μm, and/or the thickness of the second coating layer is 30 μm-50 μm.
When the first coating layer is a lithium iron manganese phosphate coating layer, the metal manganese in the first coating layer is gradually dissolved out along with the increase of the cycle times of the energy storage device, if the first coating layer is thinner, namely, when the thickness of the first coating layer is smaller than 30 mu m, the cycle performance of the energy storage device is poorer, and when the thickness of the first coating layer is larger than 50 mu m, the processing difficulty of the first coating layer is increased because the thickness of the first coating layer is thicker, and based on the processing difficulty, the thickness of the first coating layer is 30 mu m-50 mu m, so that the cycle performance of the energy storage device can be improved, and the processing difficulty of the first coating layer can be simplified.
In addition, when the thickness of the second coating layer is smaller than 30 μm, and the second coating layer is a ternary material coating layer, the protection effect of the second coating layer on the first coating layer is weaker, the possibility of metal manganese in the first coating layer is still present, and when the thickness of the second coating layer is larger than 50 μm, electrolyte is harder to pass through the second coating layer and the first coating layer because the thickness of the second coating layer is thicker, so that the material characteristics of the first coating layer are difficult to exert, and the performance of the energy storage device is influenced, and based on the electrolyte, the thickness of the second coating layer is 30 μm-50 μm, so that the protection performance of the second coating layer can be improved, the material characteristics of the first coating layer can be exerted, and the performance of the energy storage device is improved.
In a possible implementation manner of the first aspect, the depth of the conductive fibers inserted into the first coating layer and the second coating layer is 2 μm-6 μm.
When the depth of the conductive fiber inserted into the first coating layer and the second coating layer is smaller than 2 μm, on one hand, the effect of improving the structural strength of the positive electrode sheet is weaker because the depth of the conductive fiber inserted into the first coating layer and the second coating layer is shallower, on the other hand, the effect of improving the interface resistance between the first coating layer and the second coating layer is also weaker, and when the depth of the conductive fiber inserted into the first coating layer and the second coating layer is larger than 6 μm, although the structural strength of the positive electrode sheet can be enhanced by the conductive fiber, the effect of improving the interface resistance between the first coating layer and the second coating layer is weakened, and meanwhile, the process difficulty of setting the conductive fiber is increased, and on the basis of the effect, the depth of the conductive fiber inserted into the first coating layer is 2 μm-6 μm, so that the structural strength of the positive electrode sheet can be improved, the interface resistance can be improved, and the process difficulty of setting the conductive fiber can be simplified.
In a second aspect, the present invention also provides an energy storage device, including the positive electrode sheet according to any one of the first aspects.
In a third aspect, the present invention further provides a method for preparing the positive electrode sheet, where the method is used for preparing the positive electrode sheet according to the first aspect, and the method includes:
step one, coating a first coating layer on a current collector;
inserting conductive fibers into one side surface of the first coating layer, which is away from the current collector, and enabling part of the conductive fibers to extend out of one side surface of the first coating layer, which is away from the current collector;
and thirdly, coating a second coating layer on one side of the first coating layer, in which the conductive fibers are inserted, so that the conductive fibers extending out of the first coating layer are inserted into the second coating layer.
Therefore, before the second coating layer is coated on the first coating layer, the conductive fiber is arranged on the first coating layer, then the second coating layer is coated on one side surface of the first coating layer provided with the conductive fiber, so that one end of the conductive fiber can be inserted into the second coating layer, on one hand, compared with the direct joint connection of the first coating layer and the second coating layer, the two ends of the conductive fiber are respectively inserted into the first coating layer and the second coating layer through arranging the conductive fiber, the first coating layer and the second coating layer can be connected through the conductive fiber, the connection stability between the first coating layer and the second coating layer is improved, and the structural strength of the positive electrode plate is improved.
In a possible implementation manner of the second aspect, the step two includes:
the conductive fibers are inserted into a surface of the first coating layer facing away from the current collector by a needle injection device or an electrostatic spraying device.
Thus, the conductive fiber can be inserted into the first coating layer by using a needle injection device or an electrostatic spraying device, and the operation is simple.
In a possible implementation manner of the second aspect, the inserting the conductive fiber into a side surface of the first coating layer facing away from the aluminum foil by using a needle injection device includes:
adjusting the injection direction of an injection head of the needle tube injection device to be perpendicular to the upper surface of the first coating layer;
moving the injector head height to within a range of 1.5 to 4.5mm above a side surface of the first coating layer facing away from the current collector;
and starting the needle tube injection device so that part of the conductive fibers in the needle tube injection device are inserted into the surface of one side of the first coating layer, which is away from the current collector.
Therefore, the insertion direction of the conductive fiber can be adjusted by adjusting the injection direction of the injection head, and the operation is simple.
In a possible implementation manner of the second aspect, the preparation method includes:
The needle injection device inserts the conductive fiber in a state that the first coating layer is not completely dried.
Thus, the first coating layer in the incompletely dried state is softer, and the resistance of the conductive fiber inserted into the first coating layer can be made smaller.
In a possible implementation manner of the second aspect, the step one includes:
weighing the following components in percentage by mass: 2%:3% of lithium iron manganese phosphate, conductive carbon black and polyvinylidene fluoride are stirred to form first slurry;
the first paste is extruded and uniformly coated on the current collector to form the first coating layer.
From this, through weighing the mass ratio to be 95%:2%:3% of lithium iron manganese phosphate, conductive carbon black and polyvinylidene fluoride, and can form a first coating layer with good material effect.
In a possible implementation manner of the second aspect, the applying a second coating layer on the side of the first coating layer where the conductive fiber is disposed includes:
weighing the following components in percentage by mass: 2%:3% of ternary material, conductive carbon black and polyvinylidene fluoride are stirred to form second slurry;
and extruding the second slurry and uniformly coating one side surface of the first coating layer, on which the conductive fibers are arranged, so as to form the second coating layer.
Thus, the passing mass ratio is 95%:2%:3% of ternary material, conductive carbon black and polyvinylidene fluoride can form a second coating layer with good material effect.
In a fourth aspect, the present invention further provides a method for preparing an energy storage device, the method comprising:
preparing a positive electrode plate, wherein the positive electrode plate is prepared by the preparation method of the positive electrode plate in the third aspect;
providing a negative electrode plate and a diaphragm;
assembling the positive electrode plate, the diaphragm and the negative electrode plate and winding to form a winding type electrode assembly;
providing an end cap assembly and connecting with the coiled electrode assembly;
providing a shell, mounting the coiled electrode assembly into the shell and welding and fixing the end cover assembly and the shell;
providing electrolyte, injecting the electrolyte into the shell, and packaging after formation;
and providing an outer envelope, and wrapping the outer peripheral wall of the shell to form an energy storage device monomer.
Because the positive electrode plate in the preparation method of the energy storage device is prepared by adopting the preparation method of the positive electrode plate in the second aspect, the energy storage device prepared by adopting the preparation method of the energy storage device has high energy density and better comprehensive performance.
Compared with the prior art, the application has at least the following beneficial effects:
In this application, owing to be provided with interface connection structure between first coating layer and second coating layer, and the one end of the conductive fiber in the interface connection structure inserts in the one side surface that first coating layer deviates from the electric current collector, the other end inserts in the one side surface that the second coating layer was towards first coating layer, consequently, on the one hand, compare in first coating layer and the direct laminating of second coating layer and be connected, through setting up conductive fiber, and make the both ends of conductive fiber insert respectively in first coating layer and the second coating layer, can make between first coating layer and the second coating layer connect through conductive fiber, thereby improve the connection stability between first coating layer and the second coating layer, and then improved the structural strength of positive pole piece, on the other hand, because conductive fiber is made by the chemical fiber that has conductive medium, wire or carbon fiber etc. consequently, through setting up conductive fiber between first coating layer and or second coating layer, interface resistance between first coating layer and second coating layer, thereby the electrochemical performance of the energy storage device that is formed by the positive pole piece has been improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and 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 diagram of a positive electrode sheet according to an embodiment of the present invention;
FIG. 2 is a table showing the electrochemical performance of the energy storage device according to the thickness of the second coating layer according to the embodiment of the present invention;
FIG. 3 is an enlarged partial schematic view at A of FIG. 1;
FIG. 4 is a table showing the electrochemical performance of the energy storage device according to the insertion depth of the conductive fibers according to the embodiment of the present invention;
fig. 5 is a flowchart of the preparation of the positive electrode sheet according to the embodiment of the present invention;
fig. 6 is a schematic structural diagram of a first coating layer formed on a current collector according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a structure of providing conductive fibers on a first coating layer according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a positive electrode sheet according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of an electrostatic spraying device provided by an embodiment of the present invention, in which conductive fibers are disposed;
FIG. 10 is a schematic view of a structure of a needle injection device provided with conductive fibers according to an embodiment of the present invention;
FIG. 11 is a flowchart of a first coating layer formation according to an embodiment of the present invention;
FIG. 12 is a flow chart of a second coating layer formation provided by an embodiment of the present invention;
fig. 13 is a flowchart of a preparation of an energy storage device according to an embodiment of the present invention.
Reference numerals illustrate:
100-positive pole piece; 110-current collector; 120-a first coating layer; 130-a second coating layer; 140-interface connection structure; 141-conductive fibers; 151-electrostatic spraying device.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the present invention, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate an azimuth or a positional relationship based on that shown in the drawings. These terms are only used to better describe the present invention and its embodiments and are not intended to limit the scope of the indicated devices, elements or components to the particular orientations or to configure and operate in the particular orientations.
Also, some of the terms described above may be used to indicate other meanings in addition to orientation or positional relationships, for example, the term "upper" may also be used to indicate some sort of attachment or connection in some cases. The specific meaning of these terms in the present invention will be understood by those of ordinary skill in the art according to the specific circumstances.
Furthermore, the terms "mounted," "configured," "provided," "connected," and "connected" are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; may be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements, or components. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
Furthermore, the terms "first," "second," and the like, are used primarily to distinguish between different devices, elements, or components (the particular species and configurations may be the same or different), and are not used to indicate or imply the relative importance and number of devices, elements, or components indicated. Unless otherwise indicated, the meaning of "a plurality" is two or more.
As described in the background art of the present application, in the preparation of the positive electrode sheet, a main material is first added into a stirrer to perform stirring and premixing to obtain a mixture, then the mixture and an organic solvent are stirred and dispersed under a vacuum condition, then the organic solvent is added to perform high-speed stirring and dispersing to obtain a mixed slurry, the mixed slurry is screened to remove large particles in the mixed slurry, so as to obtain a positive electrode slurry, finally the positive electrode slurry is coated on a current collector to form a first coating layer, and after the first coating layer is sufficiently dried, another positive electrode slurry is coated on the first coating layer to form a second coating layer, so that the positive electrode sheet is obtained.
However, in the related art, since the first coating layer and the second coating layer are bonded to each other, the connection stability between the first coating layer and the second coating layer is weak, so that the structural strength of the positive electrode plate is poor, and meanwhile, the contact resistance between the first coating layer and the second coating layer is increased, thereby affecting the exertion of the electrochemical performance of the energy storage device.
In order to solve the technical problems mentioned in the background art, the invention provides an anode plate, an energy storage device and a preparation method, wherein an interface connection structure is arranged between a first coating layer and a second coating layer, one end of a conductive fiber in the interface connection structure is inserted into one side surface of the first coating layer, which is far away from a current collector, and the other end of the conductive fiber is inserted into one side surface of the second coating layer, which is far towards the first coating layer, so that on one hand, compared with the direct bonding connection of the first coating layer and the second coating layer, the two ends of the conductive fiber are respectively inserted into the first coating layer and the second coating layer, the connection stability between the first coating layer and the second coating layer can be improved through the conductive fiber, and the structural strength of the anode plate is improved.
The present application is described in detail below by way of specific examples:
referring to fig. 1, an embodiment of the present application provides a positive electrode tab 100, where the positive electrode tab 100 includes a current collector 110, a first coating layer 120, a second coating layer 130, and an interface connection structure 140, where the first coating layer 120 is stacked on the current collector 110; the second coating layer 130 is stacked on a surface of the first coating layer 120 facing away from the current collector 110; the interfacing structure 140 includes conductive fibers 141, one end of the conductive fibers 141 being inserted into a side surface of the first coating layer 120 facing away from the current collector 110, and the other end being inserted into a side surface of the second coating layer 130 facing the first coating layer 120.
In this embodiment, since the interface connection structure 140 is disposed between the first coating layer 120 and the second coating layer 130, and one end of the conductive fiber 141 in the interface connection structure 140 is inserted into the surface of one side of the first coating layer 120 facing away from the current collector 110, and the other end is inserted into the surface of one side of the second coating layer 130 facing toward the first coating layer 120, on the one hand, compared with the direct bonding connection of the first coating layer 120 and the second coating layer 130, by disposing the conductive fiber 141 and inserting the two ends of the conductive fiber 141 into the first coating layer 120 and the second coating layer 130 respectively, the connection stability between the first coating layer 120 and the second coating layer 130 is improved through the conductive fiber 141, and the structural strength of the positive electrode sheet 100 is further improved, and on the other hand, since the conductive fiber 141 is made of a chemical fiber, a metal wire, a carbon fiber, or the like with a conductive medium, the interface resistance between the first coating layer 120 and the second coating layer 130 can be reduced, and the performance of the electrochemical energy storage device formed by the machine sheet is improved.
It should be noted that, the positive electrode tab 100 refers to a positive electrode tab in which two material layers (i.e., the first coating layer 120 and the second coating layer 130) are coated on the current collector 110, where the first coating layer 120 and the second coating layer 130 may be the same material layer or different material layers.
In addition, the second coating layer 130 is coated on the first coating layer 120, it being understood that the second coating layer 130 completely covers the first coating layer 120.
In addition, the conductive fibers 141 include a plurality of conductive fibers 141, and the plurality of conductive fibers 141 are spaced apart from one side surface of the first coating layer 120 facing away from the current collector 110, and the more the number of conductive fibers 141, the smaller the distance between every two adjacent conductive fibers 141, the more significant the effect of the conductive fibers 141 on improving the interfacial resistance between the first coating layer 120 and the second coating layer 130. The number of the conductive fibers 141 and the interval between every two adjacent conductive fibers 141 are not limited, and those skilled in the art can plan the structural strength and the improvement degree of the interfacial resistance of the positive electrode sheet 100 according to the conductive fibers 141.
In some possible embodiments, the first coating layer 120 is a lithium manganese iron phosphate coating layer and the second coating layer 130 is a ternary material coating layer.
The voltage plateau of lithium manganese phosphate is 4.1V, which is far higher than the voltage plateau (3.4V) of lithium iron phosphate, so that the energy density of lithium manganese phosphate is higher than that of lithium iron phosphate, and therefore, the energy density of the energy storage device formed by the positive electrode plate 100 can be improved by adopting the lithium manganese phosphate coating layer, and in addition, the metal manganese in the lithium manganese phosphate can be gradually dissolved out along with the increase of the cycle number of the energy storage device, thereby influencing the performance of the energy storage device, based on the fact, the second coating layer 130 is a ternary material coating layer, and the ternary material coating layer can serve as a protective layer to inhibit the dissolution of the metal manganese in the lithium manganese phosphate, so that the energy density of the energy storage device can be improved and the cycle performance of the energy storage device can be improved by enabling the first coating layer 120 to be the lithium manganese phosphate coating layer and the second coating layer 130 to be a ternary material coating layer.
In some possible embodiments, referring to FIG. 1, first coating layer 120 has a thickness of 30 μm to 50 μm and/or second coating layer 130 has a thickness of 30 μm to 50 μm.
Wherein the thickness of the first coating layer 120 is a distance denoted by a in fig. 1, and the thickness of the second coating layer 130 is a distance denoted by b in fig. 1.
When the first coating layer 120 is a lithium iron manganese phosphate coating layer, since the metal manganese in the first coating layer 120 will gradually dissolve out with the increase of the cycle times of the energy storage device, if the first coating layer 120 is thinner, i.e. when the thickness of the first coating layer 120 is smaller than 30 μm, the cycle performance of the energy storage device is poorer, and when the thickness of the first coating layer 120 is larger than 50 μm, the processing difficulty of the first coating layer 120 is increased because the thickness of the first coating layer 120 is thicker, and based on this, the thickness of the first coating layer 120 is 30 μm-50 μm, so that the cycle performance of the energy storage device can be improved, and the processing difficulty of the first coating layer 120 can be simplified.
In addition, when the thickness of the second coating layer 130 is less than 30 μm and the second coating layer 130 is a ternary material coating layer, the protection effect of the second coating layer 130 on the first coating layer 120 is weak, and there is still a possibility that manganese metal in the first coating layer 120 is dissolved out, and when the thickness of the second coating layer 130 is greater than 50 μm, since the thickness of the second coating layer 130 is thicker, it is difficult for electrolyte to pass through the second coating layer 130 and the first coating layer 120, thereby making it difficult to exert the material characteristics of the first coating layer 120, and consequently affecting the performance of the energy storage device, and based on this, the thickness of the second coating layer 130 is 30 μm to 50 μm, thus, not only improving the protection performance of the second coating layer 130, but also exerting the material characteristics of the first coating layer 120, thereby improving the performance of the energy storage device.
As shown in fig. 2, the data obtained by performing a chemical performance test on the energy storage device prepared by using the positive electrode sheet 100, specifically, performing an electrochemical performance test on the energy storage device by using a battery tester, wherein the peel force test in fig. 2 is to intercept the positive electrode sheet 100 with 20mm x 70mm, adhere the second coating layer 130 with a 3M double-sided adhesive tape, and perform a 180 ° peel test with a strain rate of 10mm/min by a high-iron tensile machine, and the result is based on the average value of the peel force in the length direction, and the calculation mode of the capacity retention rate in fig. 2 is to be the value of the capacity retention rate obtained by dividing the capacity of the 150 th turn by the initial capacity in the 1C charge-discharge test.
When the first coating layer 120 is 30 μm, the electrochemical performance of the energy storage device increases and decreases as the thickness of the second coating layer 130 increases in a different state in which the thickness of the second coating layer 130 increases from 30 μm to 50 μm, that is, the electrochemical performance of the energy storage device increases as the thickness of the second coating layer 130 increases from 30 μm to 40 μm, and the electrochemical performance of the energy storage device decreases as the thickness of the second coating layer 130 increases from 40 μm to 50 μm. In addition, as the thickness of the second coating layer 130 increases, the peeling force of the positive electrode tab gradually decreases, and the interfacial resistance between the first coating layer 120 and the second coating layer 130 gradually increases.
In some possible embodiments, referring to FIG. 3, conductive fibers 141 are inserted into first coating layer 120 and second coating layer 130 to a depth of 2 μm-6 μm.
Wherein the conductive fibers 141 are inserted into the first coating layer 120 to a depth of a distance shown as d in fig. 3.
When the depth of the conductive fiber 141 inserted into the first and second coating layers 120 and 130 is less than 2 μm, on one hand, since the depth of the conductive fiber 141 inserted into the first coating layer 120 is shallow, the effect of improving the structural strength of the positive electrode sheet 100 is weak, and on the other hand, the effect of improving the interfacial resistance between the first and second coating layers 120 and 130 is weak, and when the depth of the conductive fiber 141 inserted into the first and second coating layers 120 and 130 is greater than 6 μm, although the effect of the conductive fiber 141 can enhance the structural strength of the positive electrode sheet 100, the effect of improving the interfacial resistance between the first and second coating layers 120 and 130 is weakened, and meanwhile, the process difficulty of setting the conductive fiber 141 is increased, based on this, the depth of the conductive fiber 141 inserted into the first and second coating layers 120 and 130 is 2 μm to 6 μm, so that the structural strength of the positive electrode sheet 100 can be improved, the interfacial resistance can be improved, and the process of setting the conductive fiber 141 can be simplified.
As shown in fig. 4, the energy storage device tested in the table is the same as the energy storage device in fig. 2, and it is seen that the electrochemical performance of the energy storage device is first increased to decrease as the depth of insertion of the conductive fiber 141 is deeper, specifically, the peeling force of the positive electrode tab 100 is increased with the increase of the depth of insertion of the conductive fiber 141 when the depth of insertion of the conductive fiber 141 is from 2 μm to 5 μm, and the peeling force of the positive electrode tab 100 is decreased with the increase of the depth of insertion of the conductive fiber 141 when the depth of insertion of the conductive fiber 141 is from 5 μm to 6 μm, and in addition, the interfacial resistance between the first coating layer 120 and the second coating layer 130 is gradually decreased as the depth of insertion of the conductive fiber 141 is deeper.
In addition, referring to fig. 2 and 4 in combination, the positive electrode sheet 100 in the present embodiment is compared with the case where the conductive fiber 141 is not disposed between the first coating layer 120 and the second coating layer 130 in the comparative example in different states, respectively, and it is seen that the structural strength of the positive electrode sheet 100 in the comparative example is weaker than the positive electrode sheet 100 in the present embodiment where the conductive fiber 141 is disposed (judged in terms of the magnitude of the peeling force), and the interface resistance is high and the electrochemical performance is poor.
Referring to fig. 5 to fig. 8 in combination, the embodiment of the present application further provides a preparation method of the positive electrode sheet 100, where the preparation method is used to prepare the positive electrode sheet 100 in the foregoing embodiment, and the preparation method includes:
S100, coating a first coating layer on the current collector.
Specifically, referring to fig. 6, lithium manganese phosphate, conductive carbon black, polyvinylidene fluoride are put in a certain ratio into a stirring tank, and then an appropriate amount of N-methylpyrrolidone is added into the stirring tank, and then stirred for a large preset time, for example, for 6 hours, to obtain a first slurry having an appropriate viscosity, and then the first slurry is coated on one side surface of the current collector 110 to form the first coating layer 120.
And S200, inserting conductive fibers into the surface of one side of the first coating layer, which is away from the current collector, and enabling parts of the conductive fibers to extend out of the side of the first coating layer, which is away from the current collector.
The conductive fibers 141 include a plurality of conductive fibers, and one ends of the plurality of conductive fibers 141 are sequentially inserted into a side surface of the first coating layer 120 facing away from the current collector 110, respectively, or one ends of the plurality of conductive fibers 141 are simultaneously inserted into a side surface of the first coating layer 120 facing away from the current collector 110.
Specifically, referring to fig. 7, a plurality of conductive fibers 141 are first dissolved in N-methylpyrrolidone, and then stirred for a certain time to obtain a slurry of the uniformly mixed conductive fibers 141, and then the slurry of the conductive fibers 141 is inserted into a surface of the first coating layer 120 facing away from the current collector 110 using an auxiliary device.
In addition, the depth of the conductive fiber 141 extending into the first coating layer 120 and the length of the conductive fiber 141 extending out of the first coating layer 120 may be equal or unequal, and for example, when the depth of the conductive fiber 141 extending into the first coating layer 120 and the length of the conductive fiber 141 extending out of the first coating layer 120 are equal, the connection strength between the conductive fiber 141 and the first coating layer 120 and the connection strength between the conductive fiber 141 and the second coating layer 130 can be made equal, thereby further improving the connection effect between the first coating layer 120 and the second coating layer 130.
And S300, coating a second coating layer on one side of the first coating layer, where the conductive fibers are inserted, so that the conductive fibers extending out of the first coating layer are inserted into the second coating layer.
Specifically, referring to fig. 8, a ternary material, conductive carbon black, and polyvinylidene fluoride are put in a stirring tank in a certain ratio, and an appropriate amount of N-methylpyrrolidone is added to the stirring tank, and then the stirring tank is started to stir for a preset time, for example, for 6 hours, to obtain an appropriate second slurry, and then the second slurry is coated on a side surface of the first coating layer 120 facing away from the current collector 110, and since the side surface of the first coating layer 120 facing away from the current collector 110 is provided with conductive fibers 141, and the conductive fibers 141 protrude from the first coating layer 120, the conductive fibers 141 protruding from the first coating layer 120 will be inserted into the second coating layer 130.
Therefore, before the second coating layer 130 is coated on the first coating layer 120, the conductive fiber 141 is disposed on the first coating layer 120, and then the second coating layer 130 is coated on one side surface of the first coating layer 120 on which the conductive fiber 141 is disposed, so that one end of the conductive fiber 141 can be inserted into the second coating layer 130, on the one hand, compared with the direct bonding connection of the first coating layer 120 and the second coating layer 130, by disposing the conductive fiber 141 and inserting the two ends of the conductive fiber 141 into the first coating layer 120 and the second coating layer 130 respectively, the connection between the first coating layer 120 and the second coating layer 130 can be made through the conductive fiber 141, thereby improving the connection stability between the first coating layer 120 and the second coating layer 130, and further improving the structural strength of the positive electrode sheet 100, on the other hand, since the conductive fiber 141 is made of a chemical fiber, a metal wire, a carbon fiber or the like with a conductive medium, the interfacial resistance between the first coating layer 120 and the second coating layer 130 can be reduced, and the performance of the energy storage device formed by the positive electrode sheet can be improved.
In some possible embodiments, step S200 includes: conductive fibers 141 are inserted into a surface of the first coating layer 120 on a side facing away from the current collector 110 using a needle injection device or an electrostatic spray device 151.
Specifically, in the process of inserting the conductive fiber 141 into the first coating layer 120 using the syringe injection device, the injection amount, the moving speed and the injection frequency of the injection head of the syringe injection device are controlled to extend the slurry of the conductive fiber 141 into the inside of the first coating layer 120 to insert the conductive fiber 141 into the inside of the first coating layer 120.
Referring to fig. 9, when the conductive fiber 141 is inserted into the first coating layer 120 using the electrostatic spraying device 151, the current collector 110 is connected to the grounded electrode such that a voltage is applied between it and the electrostatic spraying device 151, so that the spraying port of the electrostatic spraying device 151 sprays the charged conductive fiber 141 against the first coating layer 120.
Thus, the conductive fiber 141 can be inserted into the first coating layer 120 by using the syringe injection device or the electrostatic spraying device 151, and the operation is simple.
In some possible embodiments, referring to fig. 10, inserting conductive fibers 141 into a side surface of first coating layer 120 facing away from current collector 110 using a needle cannula injection device includes:
S210, adjusting the injection direction of the needle tube injection device to be perpendicular to the upper surface of the first coating layer.
Specifically, before the injection is started, the injection direction of the injection head is adjusted manually or automatically until the injection direction of the injection head is perpendicular to the upper surface of the first coating layer 120, wherein the perpendicular is approximately perpendicular, and is not understood to be completely perpendicular.
It should be noted that the injection direction of the injection head is not limited to the above, and the injection direction of the injection head may also form an acute angle or an obtuse angle with the upper surface of the first coating layer 120.
And S220, moving the height of the injection head to be within a range of 1.5mm to 4.5mm above the surface of one side of the first coating layer, which faces away from the current collector.
Specifically, the adjusted injection head is moved to a range of 1.5mm to 4.5mm above a side surface of the first coating layer 120 facing away from the current collector 110, that is, directly above an area where the conductive fibers 141 are to be disposed, so that the injection head can dispose the conductive fibers 141 on the first coating layer 120 when the needle injection device is started. In addition, adjusting the injection head within a range of 1.5mm to 4.5mm above a side surface facing away from the current collector 110 can not only enable the injection head to insert the conductive fibers 141 into the first coating layer 120 quickly, but also ensure that a portion of the conductive fibers 141 is exposed out of the upper surface of the first coating layer 120.
S230, starting the needle tube injection device so that part of conductive fibers in the needle tube injection device are inserted into the surface of one side of the first coating layer, which is away from the current collector.
Specifically, the syringe injection device includes a storage bin, the storage bin is communicated with the injection head and is used for storing the slurry of the conductive fibers 141, and when the syringe injection device is pressurized and extruded, the slurry of the conductive fibers 141 in the storage bin is inserted into the first coating layer 120 through the injection head. The first coating layer 120 provided with the conductive fibers 141 is then sufficiently dried by an oven (the drying temperature of the oven is about 120 c for about 5 hours) to form the first coating layer 120 having the specially distributed conductive fibers 141.
Thereby, the insertion direction of the conductive fiber 141 can be adjusted by adjusting the injection direction of the injection head, and the operation is simple.
In some possible embodiments, the method of making comprises:
the needle injection device inserts the conductive fiber 141 in a state that the first coating layer 120 is not completely dried.
Thus, the first coating layer 120 in an incompletely dried state is softer, and the resistance of the conductive fibers 141 inserted into the first coating layer 120 can be made smaller.
The humidity of the first coating layer 120 in the incompletely dried state is about 30%, for example, the humidity of the first coating layer 120 in the incompletely dried state is 30%, 31%, or the like.
In some possible embodiments, referring to fig. 11, step S100 in the preparation method of the positive electrode tab, coating the first coating layer on the current collector includes:
s110, weighing the following components in percentage by mass: 2%:3% of lithium iron manganese phosphate, conductive carbon black and polyvinylidene fluoride are stirred to form uniform first slurry.
Specifically, the mass ratio was 95%:2%:3% of lithium iron manganese phosphate, conductive carbon black and polyvinylidene fluoride are placed in a stirring tank, N-methyl pyrrolidone is placed in the stirring tank, the stirring tank is started to stir, the materials are uniformly mixed to form uniform first slurry, and of course, large particles in the first slurry are screened out to ensure the quality of the first coating layer 120.
And S120, extruding the first slurry and uniformly coating the first slurry on the current collector to form a first coating layer.
Specifically, the first paste is uniformly applied to the current collector 110 by means of extrusion, and the contact effect between the first coating layer 120 and the current collector 110 can be improved.
From this, through weighing the mass ratio to be 95%:2%:3% of lithium iron manganese phosphate, conductive carbon black and polyvinylidene fluoride can form the first coating layer 120 with good material effect.
In some possible embodiments, referring to fig. 12, step S300 includes:
s310, weighing the following components in percentage by mass: 2%:3% of the ternary material, conductive carbon black and polyvinylidene fluoride are stirred to form a second slurry.
Specifically, the mass ratio was 95%:2%:3% of ternary material, conductive carbon black and polyvinylidene fluoride are placed in a stirring tank, N-methyl pyrrolidone is placed in the stirring tank, the stirring tank is started to stir, the materials are uniformly mixed to form uniform second slurry, and of course, large particles in the second slurry are screened out to ensure the quality of the first coating layer 120.
And S320, extruding the second slurry and uniformly coating the second slurry on one side surface of the first coating layer, on which the conductive fibers are arranged, so as to form a second coating layer.
Specifically, the second paste is uniformly applied to the second paste by means of extrusion, and the contact effect between the second coating layer 130 and the first coating layer 120 can be improved.
Thus, the passing mass ratio is 95%:2%:3% of the ternary material, conductive carbon black and polyvinylidene fluoride can form the second coating layer 130 with better material effect.
Referring to fig. 13, an embodiment of the present application further provides a method for preparing an energy storage device, where the method includes:
S10, preparing a positive pole piece.
Specifically, the preparation method of the positive electrode sheet is the preparation method of the positive electrode sheet 100 in the above embodiment, and thus is not repeated here.
S20, providing a negative electrode plate and a diaphragm.
S30, assembling the positive electrode plate, the diaphragm and the negative electrode plate and winding to form the winding type electrode assembly.
And S40, providing an end cover assembly and connecting with the winding type electrode assembly.
S50, providing a shell, installing the coiled electrode assembly into the shell, and welding and fixing the end cover assembly and the shell.
S60, providing electrolyte, injecting the electrolyte into the shell, and packaging after formation.
And S70, providing an outer envelope, and wrapping the outer peripheral wall of the shell to form an energy storage device monomer.
Because the positive electrode plate in the preparation method of the energy storage device is prepared by adopting the preparation method of the positive electrode plate 100 in the embodiment, the energy storage device prepared by adopting the preparation method of the energy storage device has high energy density and good comprehensive performance.
In the pole piece performance test, the button cell is assembled and tested, and the button cell is assembled by placing the positive pole piece 100 and the negative pole piece in a press machine respectively for pressing to eliminate vacuum bubbles in the positive pole piece and the negative pole piece. Then, the pressed positive electrode sheet 100 and negative electrode sheet are cut to form a positive electrode wafer of a first preset diameter and a negative electrode wafer of a second preset diameter (wherein the first preset diameter is smaller than the second preset diameter), and then, the positive electrode sheet 100 and the negative electrode sheet are cut respectively by using a puncher, and the diameter of the positive electrode wafer is 15mm, that is, the first preset diameter is 15mm, and the diameter of the negative electrode wafer is 18mm, that is, the second preset diameter is 18mm, for example. Finally, respectively placing the anode wafer and the cathode wafer into a glove box filled with protective atmosphere (such as argon) for assembly, then assembling the anode wafer, the cathode wafer, the polyethylene diaphragm and other components together, and then injecting electrolyte to form the energy storage device, wherein the electrolyte is prepared by using 1mol/L lithium hexafluorophosphate to be dissolved in a molar ratio of 1:1 and diethyl carbonate. Through the first preset diameter being smaller than the second preset diameter, lithium precipitation on the negative electrode plate can be avoided, and therefore performance of the prepared energy storage device is guaranteed.
The embodiment of the application also provides an energy storage device, which comprises the positive electrode plate 100 in the embodiment.
The energy storage device may be a lithium battery, a button battery, a power battery, or the like. Of course, the energy storage device can also be prepared by adopting the preparation method of the energy storage device.
Therefore, the energy storage device has high energy density and good comprehensive performance.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (12)
1. A positive electrode sheet, characterized by comprising:
a current collector;
a first coating layer stacked on the current collector;
the second coating layer is arranged on one side surface of the first coating layer, which is away from the current collector, in a stacked manner;
The interface connection structure comprises conductive fibers, wherein one ends of the conductive fibers are inserted into one side surface of the first coating layer, which faces away from the current collector, and the other ends of the conductive fibers are inserted into one side surface of the second coating layer, which faces towards the first coating layer.
2. The positive electrode sheet according to claim 1, wherein the first coating layer is a lithium iron manganese phosphate coating layer and the second coating layer is a ternary material coating layer.
3. The positive electrode sheet according to claim 2, wherein the thickness of the first coating layer is 30 μm to 50 μm and/or the thickness of the second coating layer is 30 μm to 50 μm.
4. The positive electrode sheet according to claim 1, wherein the conductive fiber is inserted into the first coating layer and the second coating layer to a depth of 2 μm to 6 μm.
5. An energy storage device comprising the positive electrode sheet of any one of claims 1-4.
6. The preparation method of the positive electrode plate is characterized by comprising the following steps:
step one, coating a first coating layer on a current collector;
inserting conductive fibers into one side surface of the first coating layer, which is away from the current collector, and enabling part of the conductive fibers to extend out of one side surface of the first coating layer, which is away from the current collector;
And thirdly, coating a second coating layer on one side of the first coating layer, in which the conductive fibers are inserted, so that the conductive fibers extending out of the first coating layer are inserted into the second coating layer.
7. The method for preparing a positive electrode sheet according to claim 6, wherein the second step comprises:
and inserting the conductive fibers into the surface of one side of the first coating layer, which faces away from the current collector, by adopting a needle tube injection device or an electrostatic injection device.
8. The method for preparing a positive electrode sheet according to claim 7, wherein the second step comprises:
adjusting the injection direction of the needle tube injection device to be perpendicular to the upper surface of the first coating layer;
moving the injector head height of the needle injection device to a range of 1.5mm to 4.5mm above a surface of the first coating layer facing away from the current collector;
and starting the needle tube injection device so that the conductive fibers in the needle tube injection device are inserted into the surface of one side of the first coating layer, which faces away from the current collector.
9. The method for preparing a positive electrode sheet according to claim 7, characterized in that the method for preparing comprises:
the needle injection device inserts the conductive fiber in a state that the first coating layer is not completely dried.
10. The method of manufacturing a positive electrode sheet according to claim 6, wherein step one comprises:
weighing the following components in percentage by mass: 2%:3% of lithium iron manganese phosphate, conductive carbon black and polyvinylidene fluoride are stirred to form first slurry;
the first paste is extruded and uniformly coated on the current collector to form the first coating layer.
11. The method of manufacturing a positive electrode sheet according to claim 6, wherein step three comprises:
weighing the following components in percentage by mass: 2%:3% of ternary material, conductive carbon black and polyvinylidene fluoride are stirred to form second slurry;
and extruding the second slurry and uniformly coating one side surface of the first coating layer, on which the conductive fibers are arranged, so as to form the second coating layer.
12. A method of manufacturing an energy storage device, the method comprising:
preparing a positive electrode sheet prepared by the method for preparing a positive electrode sheet according to any one of claims 6 to 11;
providing a negative electrode plate and a diaphragm;
assembling the positive electrode plate, the diaphragm and the negative electrode plate and winding to form a winding type electrode assembly;
providing an end cap assembly and connecting with the coiled electrode assembly;
Providing a housing, loading the coiled electrode assembly into the housing and welding and fixing the end cover assembly and the housing;
providing electrolyte, injecting the electrolyte into the shell, and packaging after formation;
providing an outer envelope, and wrapping the outer peripheral wall of the shell to form an energy storage device monomer.
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Application publication date: 20230711 |