CN114976032A - Composite pole piece, electrochemical device and electronic equipment - Google Patents
Composite pole piece, electrochemical device and electronic equipment Download PDFInfo
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- CN114976032A CN114976032A CN202210453009.2A CN202210453009A CN114976032A CN 114976032 A CN114976032 A CN 114976032A CN 202210453009 A CN202210453009 A CN 202210453009A CN 114976032 A CN114976032 A CN 114976032A
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- pole piece
- composite pole
- current collector
- thickness direction
- porosity
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- 239000002131 composite material Substances 0.000 title claims abstract description 137
- 239000011148 porous material Substances 0.000 claims abstract description 28
- 239000011149 active material Substances 0.000 claims description 73
- 150000001875 compounds Chemical class 0.000 claims description 15
- 238000002955 isolation Methods 0.000 claims description 7
- 230000004888 barrier function Effects 0.000 claims description 6
- 239000013543 active substance Substances 0.000 claims description 4
- 239000003792 electrolyte Substances 0.000 abstract description 50
- 230000005540 biological transmission Effects 0.000 abstract description 27
- 230000006866 deterioration Effects 0.000 abstract description 13
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 abstract description 9
- 229910001416 lithium ion Inorganic materials 0.000 abstract description 9
- 230000006872 improvement Effects 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000005056 compaction Methods 0.000 description 4
- 238000003475 lamination Methods 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000013329 compounding Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000007790 solid phase Substances 0.000 description 2
- QNRATNLHPGXHMA-XZHTYLCXSA-N (r)-(6-ethoxyquinolin-4-yl)-[(2s,4s,5r)-5-ethyl-1-azabicyclo[2.2.2]octan-2-yl]methanol;hydrochloride Chemical compound Cl.C([C@H]([C@H](C1)CC)C2)CN1[C@@H]2[C@H](O)C1=CC=NC2=CC=C(OCC)C=C21 QNRATNLHPGXHMA-XZHTYLCXSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- ADKPKEZZYOUGBZ-UHFFFAOYSA-N [C].[O].[Si] Chemical compound [C].[O].[Si] ADKPKEZZYOUGBZ-UHFFFAOYSA-N 0.000 description 1
- KFDQGLPGKXUTMZ-UHFFFAOYSA-N [Mn].[Co].[Ni] Chemical compound [Mn].[Co].[Ni] KFDQGLPGKXUTMZ-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 239000006258 conductive agent Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 239000011162 core material Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- 230000037427 ion transport Effects 0.000 description 1
- DCYOBGZUOMKFPA-UHFFFAOYSA-N iron(2+);iron(3+);octadecacyanide Chemical compound [Fe+2].[Fe+2].[Fe+2].[Fe+3].[Fe+3].[Fe+3].[Fe+3].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] DCYOBGZUOMKFPA-UHFFFAOYSA-N 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920000447 polyanionic polymer Polymers 0.000 description 1
- 229960003351 prussian blue Drugs 0.000 description 1
- 239000013225 prussian blue Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 230000032258 transport Effects 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Images
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
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/665—Composites
- H01M4/667—Composites in the form of layers, e.g. coatings
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- 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
- 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
- H01M4/80—Porous plates, e.g. sintered carriers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Composite Materials (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Cell Electrode Carriers And Collectors (AREA)
Abstract
The application relates to a composite pole piece, electrochemical device and electronic equipment, composite pole piece include the mass flow body, along the thickness direction of the mass flow body, and at least three mass flow body is range upon range of and is set up, and the mass flow body has seted up first pore structure, from the center of composite pole piece thickness direction to the both ends face of composite pole piece thickness direction, the porosity of the mass flow body crescent. The first pore structure can be completely infiltrated and filled by electrolyte to form a new lithium ion transmission channel, the porosity of the current collector at two end faces is large, more electrolyte can be transmitted to the current collector at the center of the composite pole piece, the porosity of the current collector at the center is small, the strength of the central current collector is guaranteed, the dynamic deterioration of the pole piece can be effectively relieved through the gradient design of the porosity of the current collector, and the transmission efficiency of the electrolyte is improved.
Description
[ technical field ] A method for producing a semiconductor device
The embodiment of the application relates to the technical field of batteries, in particular to a composite pole piece, an electrochemical device and electronic equipment.
[ background of the invention ]
With the popularization of electric vehicles, electric bicycles, and some portable electric devices, the energy density requirement of batteries is also higher. At present, the effective way to increase the energy density of the battery is to increase the active material content of the pole piece, i.e. to increase the thickness of the pole piece. However, in practical applications, when the thickness of the pole piece is increased to a certain value, the transmission channel of ions is easily blocked, which results in deterioration of the electrical performance of the battery. Therefore, how to improve the ion transmission rate on the premise of increasing the thickness of the pole piece as much as possible has become an important problem in the application prospect of the battery.
[ summary of the invention ]
The embodiment of the application aims at providing a composite pole piece, an electrochemical device and electronic equipment, so that the efficiency of electrolyte can be at least improved.
In order to solve the technical problem, the embodiment of the application adopts the following technical scheme:
in a first aspect, an embodiment of the present application provides a composite pole piece, including a current collector, along the thickness direction of the current collector, at least three the current collector is stacked. Follow the thickness direction of mass flow body, first pore structure has been seted up to the mass flow body, follows the center of compound pole piece thickness direction extremely the both ends face of compound pole piece thickness direction, the porosity of the mass flow body crescent.
Through the range upon range of setting of at least three mass flow body, can promote the bulk strength of compound pole piece. The first pore structure can be completely infiltrated and filled by electrolyte to form a new lithium ion transmission channel, the porosity of the current collector at two end faces is large, more electrolyte can be transmitted to the current collector at the center of the composite pole piece, the porosity of the current collector at the center is small, the strength of the central current collector is guaranteed, the dynamic deterioration of the composite pole piece can be effectively relieved through the gradient design of the porosity of the current collector, and the transmission efficiency of the electrolyte is improved.
As a further improvement of the above technical solution, along the thickness direction of the composite pole piece, the porosity of the current collector located at the center of the composite pole piece is 3% to 10%, and the porosity of the current collectors located at the two end faces of the composite pole piece is 10% to 30%.
The 3% -30% porosity can improve the transmission efficiency of electrolyte while guaranteeing the current collector intensity, and the porosity of each current collector can be specifically confirmed according to the quantity of the current collector in the composite pole piece, when the quantity of current collectors is more, then can suitably increase the porosity of the current collector of both ends face.
As a further improvement of the above technical solution, the area of a single first pore structure on the surface of the current collector is 0.4 to 4 square millimeters; and/or the distance between every two adjacent first pore structures on the surface of the current collector is 2-20 microns.
The area of the first hole structure of each current collector can also adopt the gradient design, the current collectors at the two end faces in the thickness direction can adopt the first hole structure with larger area, the current collectors at the center in the thickness direction can adopt the first hole structure with smaller area, and the area gradient design of the first hole structure is adopted, so that the electrolyte can be conveniently transmitted to the center of the composite pole piece from the two end faces of the composite pole piece, and the transmission rate of the electrolyte is improved.
As a further improvement of the above technical solution, the composite pole piece further includes a plurality of active material layers, and the active material layers are coated on at least one surface of each current collector. Follow the thickness direction of mass flow body, the second pore structure has been seted up on the active substance layer, follow the center of compound pole piece thickness direction extremely the both ends face of compound pole piece thickness direction, the porosity crescent on a plurality of active substance layers.
Each current collector is coated with an active material layer so that the mass fraction of the active material layer in the battery is greater to improve the energy density of the battery. The second hole structure can be completely soaked and filled by the electrolyte to form a liquid phase transmission channel of lithium ions, so that the reaction area of a solid-liquid interface is effectively increased, and the diffusion coefficient of the electrolyte in the active material layer is increased, so that the active material layer is quickly soaked. The active material layers on the two end faces and the current collectors on the two end faces have higher porosity, so that more electrolyte can be rapidly transmitted to the center of the composite pole piece, the dynamic deterioration of the composite pole piece is relieved, and the transmission efficiency of the electrolyte is improved.
As a further improvement of the above technical solution, the compacted density of the plurality of active material layers gradually increases from the center of the composite pole piece to both end faces of the composite pole piece in the thickness direction of the composite pole piece.
By controlling the compaction density of each active material layer, a porosity gradient design of the active material layer is formed, the active material layers on two end faces have larger porosity, and the compaction density of the part can be increased when the active material layers are coated, so that the energy density of the battery is improved.
As a further improvement of the above technical scheme, the porosity of each active material layer is 5% -40% to improve the transmission of the electrolyte in the thickness direction of the composite pole piece; and/or at least part of the second hole structure is communicated with the first hole structure, so that the electrolyte can easily pass through the two through holes to enter the center of the composite pole piece in the thickness direction, and the transmission rate of the electrolyte can be effectively improved.
As a further improvement of the technical scheme, the thickness of the current collector is 2-20 microns along the thickness direction of the current collector. The current collector with micron-sized thickness is also smaller in thickness after being laminated for multiple times, so that the influence on the energy density of the battery is reduced.
According to some embodiments of the present application, in a second aspect, the present application further provides an electrochemical device, including an isolation film and the composite pole piece according to any of the above embodiments, the composite pole piece is divided into a positive composite pole piece and a negative composite pole piece, the isolation film is disposed between the positive composite pole piece and the negative composite pole piece, and the positive composite pole piece, the isolation film and the negative composite pole piece are sequentially stacked or wound.
As a further improvement of the above technical solution, along the thickness direction of the positive composite pole piece, both end faces of the positive composite pole piece are provided with the isolating film, in the positive composite pole piece, the porosity of the current collector close to the isolating film is greater than the porosity of the current collector far away from the isolating film. Follow the thickness direction of the compound pole piece of negative pole, the both ends face of the compound pole piece of negative pole all is provided with the barrier film in the compound pole piece of negative pole, be close to the porosity of the mass flow body of barrier film department is greater than keeps away from the porosity of the mass flow body of barrier film department. Through the gradient design of the current collector, electrolyte is conveniently transmitted to the center of the composite pole piece, so that the dynamic deterioration of the pole piece is relieved, and the transmission of the electrolyte is improved.
According to some embodiments of the present application, in a third aspect, the present application also proposes an electronic device comprising an electrochemical device as described in any of the above embodiments.
The foregoing description is only an overview of the technical solutions of the present application, and the present application can be implemented according to the content of the description in order to make the technical means of the present application more clearly understood, and the following detailed description of the present application is given in order to make the above and other objects, features, and advantages of the present application more clearly understandable.
[ description of the drawings ]
One or more embodiments are illustrated in drawings corresponding to, and not limiting to, the embodiments, in which elements having the same reference number designation may be represented as similar elements, unless specifically noted, the drawings in the figures are not to scale.
FIG. 1 is a schematic view of a lamination of composite pole pieces according to some embodiments of the present disclosure;
FIG. 2 is a schematic illustration of a lamination of composite pole pieces according to some embodiments of the present application;
fig. 3 is a schematic structural view of a current collector of some embodiments of the present application;
FIG. 4 is a schematic illustration of lithium ion transport according to some embodiments of the present application;
fig. 5 is a schematic illustration of the application of an active material layer on a current collector according to some embodiments of the present application;
FIG. 6 is a schematic view of a lamination of composite pole pieces according to some embodiments of the present application;
fig. 7 is a schematic view of the application of an active material layer on a current collector according to some embodiments of the present application;
FIG. 8 is a schematic structural view of an electrochemical device according to some embodiments of the present application;
fig. 9 is a schematic view of a lamination of composite pole pieces within an electrochemical device according to some embodiments of the present disclosure.
In the figure:
10. compounding pole pieces;
11. a current collector; 11a, a first current collector; 11b, a second current collector; 11c, a third current collector; 11d, a fourth current collector; 11e, a fifth current collector; 111. a long side; 112. a wide side; 113. a thickness edge; 114. a major surface; 115. a first pore structure;
12. an active material layer; 121. a second pore structure;
110. compounding a pole piece with a negative electrode; 120. a positive electrode composite pole piece;
200. an isolation film;
1000. an electrochemical device.
[ detailed description ] embodiments
In order to facilitate an understanding of the present application, the present application is described in more detail below with reference to the accompanying drawings and specific embodiments. It will be understood that when an element is referred to as being "disposed" or "connected" to another element, it can be directly connected to the other element or intervening elements may be present. The terms "vertical," "upper," "lower," "left," "right," "inner," "outer," and the like as used herein are for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
In the description of the embodiments of the present application, the term "and/or" is only one kind of association relationship describing an associated object, and means that three relationships may exist, for example, a and/or B, and may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
In the description of the embodiments of the present application, the terms "first", "second", and the like are used only for distinguishing between different objects, and are not to be construed as indicating or implying relative importance or implicitly indicating the number, specific order, or primary-secondary relationship of the technical features indicated. In the description of the embodiments of the present application, "a plurality" means two or more unless specifically defined otherwise.
In addition, the technical features mentioned in the different embodiments of the present application described below may be combined with each other as long as they do not conflict with each other. Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
At present, in order to improve the problem of pole piece dynamics deterioration, when an active material layer is coated, a mode of multiple coating is usually adopted, so that different compaction densities and conductivities of the active material layers are realized, and the problem of pole piece dynamics is improved to a certain extent. However, the manufacturing cost of the pole piece is increased by multiple coating processes and different active material slurries, and the design difficulty is high.
In order to alleviate the deterioration of the pole piece dynamics and improve the transmission of the electrolyte, in a first aspect, an embodiment of the present application provides a composite pole piece 10, please refer to fig. 1 and fig. 2, where the composite pole piece 10 includes a current collector 11, and at least three current collectors 11 are stacked along the thickness direction of the current collector 11.
For the current collector 11, the current collector 11 is a conductive substrate of the composite pole piece 10, the composite pole piece 10 can be divided into a positive composite pole piece 120 and a negative composite pole piece 110, and different materials can be selected as the current collector 11 of the composite pole piece 10 according to different polarities, for example, the positive composite pole piece 120 can adopt aluminum foil or foamed aluminum as the current collector 11, and the negative composite pole piece 110 can select copper foil or foamed copper. Referring to fig. 3, fig. 3 shows a structure in which the current collector 11 is unfolded to a flat state. The current collector 11 has a flat strip structure, and the thickness of each part is substantially uniform, and the thickness of each part is usually between 2 microns and 20 microns. Current collector 11 has long side 111, wide side 112, and thickness side 113; the long side 111 is a side extending along the length direction (X direction) of the current collector 11 when the current collector 11 is unfolded to be in a flat state, the wide side 112 is a side extending along the wide side 112 (Y direction) of the current collector 11 when the current collector 11 is unfolded to be in a flat state, and the thickness side 113 is a side extending along the thickness direction (Z direction) of the current collector 11 when the current collector 11 is unfolded to be in a flat state. Current collector 11 has two major surfaces 114, where major surfaces 114 are defined by long side 111 and wide side 112, and two major surfaces 114 are disposed opposite each other along thickness side 113.
Referring to fig. 3 and 4, a first pore structure 115 is formed on the current collector 11 along the thickness direction of the current collector 11, the first pore structure 115 can be completely filled with the electrolyte to form a new lithium ion transmission channel, and the first pore structure 115 can penetrate through the current collector 11, so that the electrolytes on the two sides of the current collector 11 in the thickness direction are communicated with each other.
For the active material layer 12, the active material layer 12 is a core material layer of the composite pole piece 10, please refer to fig. 5, the active material layer 12 is coated on the main surface 114 of the current collector 11, in this embodiment, both the main surfaces 114 are coated with the active material layer 12; of course, in other embodiments, only one major surface 114 may be coated with active material layer 12. Active material layer 12 typically includes an active material, a conductive agent, a dispersant, a binder, and the like, and these materials are mixed, stirred uniformly, and applied to main surface 114 of current collector 11 to obtain active material layer 12. It is worth mentioning that the active material layer 12 has various specific components, for example, for the positive electrode composite pole piece 120, the active materials may be, for example: lithium cobaltate, lithium-rich manganese base, lithium iron phosphate manganese, nickel cobalt manganese ternary, lithium manganate, polyanion compound, Prussian blue and the like; for the negative composite pole piece 110, the active materials can be selected, for example: hard carbon, soft carbon, graphite, silicon carbon oxygen, lithium titanate, and the like.
In order to increase the thickness of the pole piece and improve the energy density of the battery, in this embodiment, referring to fig. 2, at least three current collectors 11 are stacked along the thickness direction of the current collectors 11 to form a composite pole piece 10, and two main surfaces 114 of each current collector 11 are coated with an active material layer 12, so that the mass ratio of the active material layer 12 in the battery is greater, and the energy density of the battery is improved. Through the range upon range of setting of at least three mass flow body 11, can promote the bulk strength of compound pole piece 10 to active material layer 12 can regard as lithium ion's solid phase transmission passageway, and the active material layer 12 can directly be infiltrated to electrolyte makes partial electrolyte can wear out the first pore structure 115 of mass flow body 11, so that electrolyte soaks from the both ends of compound pole piece 10 thickness direction to the center, thereby makes the active material layer 12 of every mass flow body 11 can both be infiltrated by electrolyte.
In order to further improve the transmission efficiency of the electrolyte, in this embodiment, along the thickness direction of the composite pole piece 10, from the center of the composite pole piece 10 in the thickness direction to both end faces of the composite pole piece 10 in the thickness direction, the porosity of the current collector 11 is gradually increased (that is, the porosity of the current collector 11 at both end faces is greater than the porosity of the central current collector 11). The current collectors 11 on the two end surfaces have relatively high porosity, so that more electrolyte can be transmitted to the current collectors 11 in the center of the composite pole piece 10, and the transmission efficiency of the electrolyte can be improved. The central current collector 11 does not need the electrolyte to penetrate out, so the central current collector 11 can be set to have a smaller porosity to ensure the strength of the central current collector 11. Through the gradient design of the porosity of the current collector 11, the dynamic deterioration of the pole piece can be effectively relieved, and the transmission efficiency of the electrolyte is improved.
In this embodiment, at least three current collectors 11 are stacked in the thickness direction thereof to form a composite pole piece 10, and the thickness direction of the composite pole piece 10 is the thickness direction of the current collectors 11; in addition, the centers of the composite pole pieces 10 in the thickness direction are different according to the number of the current collectors 11, when the number of the current collectors 11 is singular (the number of the current collectors 11 is at least 3), only one current collector 11 exists in the stacking center, and the current collector 11 is the center of the composite pole piece 10 in the thickness direction; when the number of current collectors 11 is double (the number of current collectors 11 is at least 3), two current collectors 11 exist in the center of the stack, and the center of the composite pole piece 10 in the thickness direction is located between the two current collectors 11, and the two current collectors 11 can be referred to as the central current collector 11.
Regarding the porosity of the current collector 11, in one embodiment, along the thickness direction of the composite pole piece 10, the porosity of the current collector 11 located at the center of the composite pole piece 10 is 3% to 10%, and the porosity of the current collector 11 located at both end faces of the composite pole piece 10 is 10% to 30%. In this embodiment, taking five current collectors 11 as an example, referring to fig. 2, the five current collectors 11 are sequentially stacked, and from top to bottom, the five current collectors 11 are respectively: first current collector 11a, second current collector 11b, third current collector 11c, fourth current collector 11d, and fifth current collector 11 e. The current collector 11 located in the center of the composite pole piece 10 in the thickness direction is the third current collector 11c, the porosity of the third current collector 11c can be set to be 3% to 10%, the porosities of the second current collector 11b and the fourth current collector 11d can be set to be the same, both the porosities are 6% to 20%, and the porosities of the first current collector 11a and the fifth current collector 11e on the two end faces can be set to be 10% to 30%. When the number of the current collectors 11 of the composite pole piece 10 is two, the current collectors 11 located at the center of the composite pole piece 10 are two, specifically, referring to fig. 6, the composite pole piece 10 includes four current collectors 11, the current collectors 11 located at the center of the composite pole piece 10 are the second current collector 11b and the third current collector 11c, the porosity of the second current collector 11b and the porosity of the third current collector 11c can be set to be 3% to 10%, and the porosity of the first current collector 11a and the porosity of the fourth current collector 11d at the two end faces can be set to be 10% to 30%. It should be noted that the porosity of each current collector 11 can be specifically determined according to the number of current collectors 11 in the composite electrode sheet 10, and when the number of current collectors 11 is large, the porosity of the current collectors 11 on both end surfaces can be increased appropriately. In this embodiment, in order to realize a gradient design in which the porosity of the current collector 11 exists from the center of the composite pole piece 10 in the thickness direction to any one end surface of the composite pole piece 10 in the thickness direction, the composite pole piece 10 at least includes three current collectors 11.
In order to facilitate the electrolyte to fully infiltrate the active material layer 12, in one embodiment, referring to fig. 7, the active material layer 12 is provided with a second hole structure 121 along the thickness direction of the composite pole piece 10. The second hole structure 121 can be completely infiltrated and filled with the electrolyte to form a liquid phase transmission channel for lithium ions, which effectively increases the reaction area of the solid-liquid interface and increases the diffusion coefficient of the electrolyte in the active material layer 12, so that the active material layer 12 is rapidly infiltrated. The second hole structure 121 can make lithium ions more easily embedded into the active material layer 12, and reduce the difficulty of lithium ion extraction from the active material layer 12, thereby improving the overall dynamics of the composite pole piece 10. The second hole structure 121 can adopt a blind hole or a through hole, when the through hole is adopted, at least part of the second hole structure 121 is communicated with the first hole structure 115, so that the electrolyte can easily pass through the two through holes to enter the center of the composite pole piece 10 in the thickness direction, and the transmission rate of the electrolyte can be effectively improved.
As for the porosity of the above active material layer 12, the porosity of each active material layer 12 may be set to 5% to 40%. In one embodiment, in order to facilitate the electrolyte to rapidly infiltrate the entire composite pole piece 10, the porosity of the active material layers 12 is gradually increased from the center of the composite pole piece 10 in the thickness direction to both end surfaces of the composite pole piece 10 in the thickness direction. For example, when the composite electrode sheet 10 includes five current collectors 11, referring to fig. 2, the porosity of the active material layer 12 on the central third current collector 11c may be set to be 5% to 15%; and the porosity of each of the active material layer 12 of the second collector 11b and the active material layer 12 of the fourth collector 11d may be set to 15% to 25%; the porosity of each of the active material layer 12 of the first current collector 11a and the active material layer 12 of the fifth current collector 11e on both end surfaces may be set to 25% to 40%. Alternatively, when the number of the composite electrode sheets 10 is two, referring to fig. 6, the porosity of the active material layer 12 of the central second current collector 11b and the porosity of the active material layer 12 of the central third current collector 11c may both be set to 5% to 20%; the porosity of the active material layer 12 of the first current collector 11a and the active material layer 12 of the fourth current collector 11d on both end surfaces may be set to 20% to 40%. It should be noted that the porosity gradient of active material layer 12 may be specifically determined according to the number of current collectors 11, and when the number of current collectors 11 is greater, the gradient may be decreased correspondingly, and conversely, the gradient may be increased. In this embodiment, the active material layers 12 on the two end surfaces and the current collectors 11 on the two end surfaces have higher porosity, so that more electrolyte can be rapidly transmitted to the center of the composite pole piece 10, the dynamic deterioration of the composite pole piece 10 is alleviated, and the transmission efficiency of the electrolyte is improved.
By rolling each active material layer 12 to a different compaction density, a porosity gradient of each current collector 11 can be achieved. The greater the compacted density of active material layer 12, the greater the energy density, but the slower the solid phase transport rate of the electrolyte. In the present application, this problem can be improved by increasing the porosity, and the larger the porosity is, the larger the contact area between active material layer 12 and the electrolyte can be increased, so as to improve the electrolyte wetting efficiency. Therefore, in one embodiment, the compacted density of the plurality of active material layers 12 gradually increases from the center of composite pole piece 10 to both end faces of composite pole piece 10 in the thickness direction of current collector 11. Since active material layer 12 on both end faces has a large porosity, the compacted density of the portion can be increased to increase the energy density when active material layer 12 is coated.
As for the above-described first pore structure 115, on the surface of the current collector 11, the shape of the first pore structure 115 may be circular, rhombic, triangular, square, elliptical, or irregular polygonal, etc., and the area of a single first pore structure 115 may be set to 0.4 mm square to 4 mm square. The area of the first pore structure 115 of each current collector 11 may also be designed in a gradient manner, for example, the area of the first pore structure 115 of each current collector 11 may be set to 3 mm to 4 mm on the surface of the current collector 11 at both end surfaces, and the area of the first pore structure 115 of the current collector 11 at the center may be set to 0.4 mm to 4 mm. The area gradient of the first hole structure 115 may be set as the case may be, without limitation. Based on the same inventive concept, the active material layer 12 of each current collector 11 may also be provided with an area gradient of the second pore structure 121 accordingly.
Each current collector 11 is provided with a plurality of first hole structures 115, in an embodiment, referring to fig. 7, the plurality of first hole structures 115 are distributed on the current collector 11 in an array, two adjacent first hole structures 115 are arranged at intervals, wherein a distance (a shortest distance between boundaries) between two adjacent first hole structures 115 may be set to be 2 micrometers to 20 micrometers. The hole pitch of the current collectors 11 at the two end faces can be set smaller to ensure larger porosity, and the hole pitch of the current collector 11 at the center can be set larger. The hole pitch may be set according to specific conditions, and is not limited herein. Similarly, a plurality of second pore structures 121 may be distributed on active material layer 12 in an array.
In the embodiment of the application, the active material layer 12 is coated on each current collector 11 through a plurality of current collectors 11 arranged in a stacked manner, so that the mass of the active material layer 12 in the battery is larger, and the energy density of the battery is improved. The current collector 11 is provided with a first pore structure 115, and along the thickness direction of the composite pole piece 10, from the center of the composite pole piece 10 to the two end faces of the composite pole piece 10, the porosity of the current collector 11 is gradually increased, and through the gradient design of the porosity of the current collector 11, the dynamic deterioration of the pole piece can be effectively relieved, and the transmission efficiency of electrolyte is improved. Meanwhile, the active material layer 12 is provided with the second hole structure 121, so that the reaction area of a solid-liquid interface is effectively increased, the diffusion coefficient of the electrolyte in the active material layer 12 is increased, the active material layer 12 is rapidly infiltrated, and the porosity gradient design of the active material layer 12 can enable more electrolytes to be rapidly transmitted to the center of the composite pole piece 10, so that the dynamic deterioration of the composite pole piece 10 is relieved, and the transmission efficiency of the electrolyte is improved.
Based on the same inventive concept, an embodiment of the present application further provides an electrochemical device 1000, please refer to fig. 8 and fig. 9, the electrochemical device 1000 includes a separator 200 and the composite pole piece 10 described in any of the above embodiments, the composite pole piece 10 is divided into a positive composite pole piece 120 and a negative composite pole piece 110, the separator 200 is disposed between the positive composite pole piece 120 and the negative composite pole piece 110 to separate the two, and the positive composite pole piece 120, the separator 200, and the negative composite pole piece 110 are sequentially stacked and wound. It should be noted that, in the embodiment of the present application, the electrochemical device 1000 is a minimum unit constituting a battery or a battery module, and is a place where conversion between electrical energy and chemical energy is specifically implemented.
The isolating film 200 is provided with various bent small holes for electrolyte transmission, in one embodiment, the isolating film 200 is provided on both end faces of the positive composite pole piece 120 along the thickness direction of the positive composite pole piece 120, and in the positive composite pole piece 120, the porosity of the current collector 11 near the isolating film 200 is greater than the porosity of the current collector 11 far away from the isolating film 200. Through the gradient design of the current collector 11, the electrolyte is conveniently transmitted to the center of the composite pole piece 10, so that the dynamic deterioration of the composite pole piece is relieved, and the transmission of the electrolyte is improved. Based on the same inventive concept, the two end faces of the negative composite pole piece 110 are both provided with the isolating films 200 along the thickness direction of the negative composite pole piece 110, and in the negative composite pole piece 110, the porosity of the current collector 11 close to the isolating film 200 is greater than the porosity of the current collector 11 far from the isolating film 200.
According to some embodiments of the present application, in a third aspect, the present application also proposes an electronic device comprising an electrochemical device 1000 as described in any of the above embodiments.
The electrochemical device 1000 disclosed in the embodiment of the present application may be used in, but is not limited to, an electronic device such as a vehicle, a ship, or an aircraft. The power supply system of the electronic device may be formed by using the electrochemical device 1000 disclosed in the present application, which is advantageous for alleviating the deterioration of the dynamics of the electrode sheet and improving the transmission of the electrolyte.
The embodiment of the present application provides an electronic device using an electrochemical device 1000 or a battery module as a power source, and the electronic device may be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, a battery car, an electric automobile, a ship, a spacecraft, and the like. The electric toy may include a stationary or mobile electric toy, such as a game machine, an electric car toy, an electric ship toy, an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, a spacecraft, etc.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; within the context of the present application, where technical features in the above embodiments or in different embodiments can also be combined, the steps can be implemented in any order and there are many other variations of the different aspects of the present application as described above, which are not provided in detail for the sake of brevity; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.
Claims (10)
1. A composite pole piece comprises current collectors, at least three current collectors are arranged in a stacking mode along the thickness direction of the current collectors, and is characterized in that,
follow the thickness direction of mass flow body, first pore structure has been seted up to the mass flow body, follows the center of compound pole piece thickness direction extremely the both ends face of compound pole piece thickness direction, the porosity of the mass flow body increases in proper order.
2. The composite pole piece according to claim 1, wherein along the thickness direction of the composite pole piece, the porosity of the current collector at the center of the composite pole piece is 3% -10%, and the porosity of the current collectors at two end faces of the composite pole piece is 10% -30%.
3. The composite pole piece according to claim 1 or 2, wherein the area of the single first pore structure on the surface of the current collector is 0.4-4 square millimeters; and/or the presence of a gas in the atmosphere,
and the distance between every two adjacent first pore structures on the surface of the current collector is 2-20 micrometers.
4. The composite pole piece of claim 1, further comprising a plurality of active material layers coated on at least one surface of each of the current collectors;
follow the thickness direction of mass flow body, the second pore structure has been seted up on the active substance layer, follows the center of compound pole piece thickness direction extremely the both ends face of compound pole piece thickness direction, the porosity crescent on a plurality of active substance layers.
5. The composite pole piece of claim 4, wherein the compacted density of the plurality of active material layers increases gradually from the center of the composite pole piece to both end faces of the composite pole piece in the thickness direction of the composite pole piece.
6. The composite pole piece of claim 4 or 5, wherein the porosity of each active material layer is 5% to 40%; and/or the presence of a gas in the gas,
at least a portion of the second pore structure is in communication with the first pore structure.
7. The composite pole piece according to any one of claim 1, wherein the thickness of the current collector in the thickness direction of the current collector is 2-20 microns.
8. An electrochemical device, comprising an isolation film and the composite pole piece of any one of claims 1 to 7, wherein the composite pole piece is divided into a positive composite pole piece and a negative composite pole piece, the isolation film is arranged between the positive composite pole piece and the negative composite pole piece, and the positive composite pole piece, the isolation film and the negative composite pole piece are sequentially stacked or wound.
9. The electrochemical device according to claim 8,
the two end faces of the positive composite pole piece are provided with the isolating films along the thickness direction of the positive composite pole piece, and in the positive composite pole piece, the porosity of a current collector close to the isolating films is larger than that of a current collector far away from the isolating films;
follow the thickness direction of negative pole composite pole piece, the both ends face of negative pole composite pole piece all is provided with the barrier film in the negative pole composite pole piece, be close to the porosity of the mass flow body of barrier film department is greater than and keeps away from the porosity of the mass flow body of barrier film department.
10. An electronic device comprising the electrochemical device according to claim 8 or 9.
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