CN117423799B - Pole piece and battery - Google Patents
Pole piece and battery Download PDFInfo
- Publication number
- CN117423799B CN117423799B CN202311713765.5A CN202311713765A CN117423799B CN 117423799 B CN117423799 B CN 117423799B CN 202311713765 A CN202311713765 A CN 202311713765A CN 117423799 B CN117423799 B CN 117423799B
- Authority
- CN
- China
- Prior art keywords
- region
- pole piece
- area
- current collector
- thickness
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000576 coating method Methods 0.000 claims abstract description 68
- 239000002346 layers by function Substances 0.000 claims abstract description 68
- 239000011248 coating agent Substances 0.000 claims abstract description 67
- 239000011888 foil Substances 0.000 claims description 74
- 239000011241 protective layer Substances 0.000 claims description 73
- 239000010410 layer Substances 0.000 claims description 61
- 239000011149 active material Substances 0.000 claims description 40
- 238000005452 bending Methods 0.000 claims description 8
- 239000013543 active substance Substances 0.000 claims description 3
- 230000007423 decrease Effects 0.000 claims description 2
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 239000007774 positive electrode material Substances 0.000 description 21
- 239000002002 slurry Substances 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 11
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 7
- 239000002033 PVDF binder Substances 0.000 description 7
- 229910052744 lithium Inorganic materials 0.000 description 7
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 6
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 6
- 229910052782 aluminium Inorganic materials 0.000 description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000003466 welding Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 150000002500 ions Chemical class 0.000 description 5
- 238000005192 partition Methods 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- GHPGOEFPKIHBNM-UHFFFAOYSA-N antimony(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Sb+3].[Sb+3] GHPGOEFPKIHBNM-UHFFFAOYSA-N 0.000 description 4
- 239000006229 carbon black Substances 0.000 description 4
- 239000010954 inorganic particle Substances 0.000 description 4
- 230000014759 maintenance of location Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 229910021393 carbon nanotube Inorganic materials 0.000 description 3
- 239000002041 carbon nanotube Substances 0.000 description 3
- 239000004020 conductor Substances 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 238000000724 energy-dispersive X-ray spectrum Methods 0.000 description 3
- 239000011810 insulating material Substances 0.000 description 3
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 3
- 239000011787 zinc oxide Substances 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 239000005955 Ferric phosphate Substances 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 229910006404 SnO 2 Inorganic materials 0.000 description 2
- HFCVPDYCRZVZDF-UHFFFAOYSA-N [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O Chemical compound [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O HFCVPDYCRZVZDF-UHFFFAOYSA-N 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- DHAHRLDIUIPTCJ-UHFFFAOYSA-K aluminium metaphosphate Chemical compound [Al+3].[O-]P(=O)=O.[O-]P(=O)=O.[O-]P(=O)=O DHAHRLDIUIPTCJ-UHFFFAOYSA-K 0.000 description 2
- ILRRQNADMUWWFW-UHFFFAOYSA-K aluminium phosphate Chemical compound O1[Al]2OP1(=O)O2 ILRRQNADMUWWFW-UHFFFAOYSA-K 0.000 description 2
- 229910021383 artificial graphite Inorganic materials 0.000 description 2
- 229910001593 boehmite Inorganic materials 0.000 description 2
- 229910000428 cobalt oxide Inorganic materials 0.000 description 2
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 description 2
- 239000006258 conductive agent Substances 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- 229940032958 ferric phosphate Drugs 0.000 description 2
- 239000003292 glue Substances 0.000 description 2
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 2
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 2
- 229910000399 iron(III) phosphate Inorganic materials 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 2
- 239000000395 magnesium oxide Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 125000005341 metaphosphate group Chemical group 0.000 description 2
- 239000007773 negative electrode material Substances 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- BLBNEWYCYZMDEK-UHFFFAOYSA-N $l^{1}-indiganyloxyindium Chemical compound [In]O[In] BLBNEWYCYZMDEK-UHFFFAOYSA-N 0.000 description 1
- MURCDOXDAHPNRQ-ZJKZPDEISA-N L-685,458 Chemical compound C([C@@H]([C@H](O)C[C@H](C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC=1C=CC=CC=1)C(N)=O)CC=1C=CC=CC=1)NC(=O)OC(C)(C)C)C1=CC=CC=C1 MURCDOXDAHPNRQ-ZJKZPDEISA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 1
- PFYQFCKUASLJLL-UHFFFAOYSA-N [Co].[Ni].[Li] Chemical compound [Co].[Ni].[Li] PFYQFCKUASLJLL-UHFFFAOYSA-N 0.000 description 1
- ZVLDJSZFKQJMKD-UHFFFAOYSA-N [Li].[Si] Chemical compound [Li].[Si] ZVLDJSZFKQJMKD-UHFFFAOYSA-N 0.000 description 1
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 238000007796 conventional method Methods 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
- 238000011161 development Methods 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
- 229920001971 elastomer Polymers 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 1
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000004005 microsphere Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 229920001909 styrene-acrylic polymer Polymers 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 229910000314 transition metal oxide Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
- 230000037303 wrinkles Effects 0.000 description 1
Classifications
-
- 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
- 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
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0404—Methods of deposition of the material by coating on electrode collectors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Connection Of Batteries Or Terminals (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Cell Electrode Carriers And Collectors (AREA)
Abstract
The invention provides a pole piece and a battery. The first aspect of the invention provides a pole piece, which comprises a current collector and a functional layer, wherein the current collector comprises a first surface and a second surface which are oppositely arranged, the first surface comprises a first coating area, the second surface comprises a second coating area, and the functional layer is arranged on the first coating area and the second coating area of the current collector; the second coating area comprises a first area and a second area, the thickness of the functional layer arranged in the second area is W1, and the total thickness of the functional layers arranged in the first coating area and the first area is W2, wherein W1/W2 is 100% or more than 70%. The pole piece provided by the invention is beneficial to improving the cycle performance of the battery.
Description
Technical Field
The invention relates to a pole piece and a battery, and relates to the technical field of batteries.
Background
As an energy storage device, the battery has higher and higher requirements on the performance of the battery along with the rapid development of the new energy field. The pole piece is used as an important component of the battery and comprises a current collector, a functional layer and a pole lug, and meanwhile, the surface of the pole lug is stuck with pole lug glue so as to prevent the battery from short circuit.
The pole piece comprises a pole piece, a current collector, a functional layer, a lug adhesive, a cathode and an anode, wherein the current collector and the functional layer are arranged on the surface of the pole piece, the thickness of the pole piece is higher than that of the functional layer, and the lug adhesive is adhered to the surface of the pole piece, so that the pole piece is more complex in structure and poor in thickness uniformity and is easy to influence the cycle performance of the battery.
Disclosure of Invention
The invention provides a pole piece which is used for improving the cycle performance of a battery.
The invention also provides a battery, which comprises the pole piece.
The first aspect of the invention provides a pole piece, which comprises a current collector 1 and a functional layer 2, wherein the current collector 1 comprises a first surface a and a second surface b which are oppositely arranged, the first surface a comprises a first coating area 111, the second surface b comprises a second coating area 121, and the functional layer 2 is arranged on the first coating area 111 and the second coating area 121 of the current collector 1;
the second coating region 121 includes a first region 1211 and a second region 1212, where the projection of the first region 1211 onto the current collector 1 coincides with the projection of the first coating region 111 onto the current collector 1, and the projection of the second region 1212 onto the current collector 1 is located in a region other than the projection of the first coating region 111 onto the current collector 1;
along the thickness direction of the pole piece, the highest thickness of the functional layer 2 arranged in the first coating area 111 is W1, the lowest thickness of the functional layer 2 arranged in the first area 1211 is W2, and the average thickness of the functional layer 2 arranged in the second area 1212 is W3, wherein W3/W1+W2 is more than or equal to 0.7.
In one embodiment, at least a portion of the first region 1211 is bent in a direction toward the first coating region 111 and forms a bent portion, which is connected to the second region 1212.
In a specific embodiment, along the thickness direction of the pole piece, the lowest value of the thickness of the functional layer 2 positioned on the bending part of the second surface b is equal to W2, and the highest value is equal to W3;
the minimum value of the thickness of the functional layer 2 on the bending part of the first surface a is 0, and the maximum value is equal to W1.
In a specific embodiment, the first surface a of the current collector further comprises a first empty foil region 112, and the second surface b further comprises a second empty foil region 122, and the projection of the second empty foil region 122 on the current collector 1 is located within the projection of the first empty foil region 112 on the current collector 1.
In one embodiment, the total area of the second empty foil region 122 and the second region 1212 is not greater than the area of the first empty foil region 112.
In one embodiment, the area of the second region 1212 is 10% -100% of the area of the first empty foil region 112.
In a specific embodiment, the tab 3 is connected to the first hollow foil region 112 or the second hollow foil region 122.
In one embodiment, the functional layer 2 includes a protective layer 21 and an active material layer 22, and the protective layer 21 and the active material layer 22 are sequentially stacked on the surface of the current collector 1;
along the length direction of the pole piece, the distance between the active material layer 22 and the pole lug 3 is D1, and the distance between the protective layer 21 and the pole lug 3 is D2, and D1-D2 is less than or equal to 0.5mm.
In one specific embodiment, the distance D2 between the protective layer 21 and the tab 3 is smaller than the distance D1 between the active material layer 22 and the tab 3, and D1-D2 is less than or equal to 0.1mm.
In one embodiment, the second region 1212 includes a first side c, a second side d, and a third side e, which form tab placement areas;
the distance between the protective layer 21 and the active material layer 22 and the first side c is D3, the distance between the protective layer 21 and the active material layer 22 and the second side D is D4, and the distance between the protective layer 21 and the active material layer 22 and the third side e is D5, D3 > D4, and D3 > D5.
In a specific embodiment, along the width direction of the pole piece, the height difference of the current collectors 1 positioned at two sides of the first side edge c is H1; along the length direction of the pole piece, the height difference of the current collectors 1 positioned at the two sides of the second side edge d is H2, the height difference of the current collectors 1 positioned at the two sides of the third side edge e is H3, H1 is less than H2, and H1 is less than H3.
A second aspect of the invention provides a battery comprising a pole piece as described in any one of the preceding claims.
According to the pole piece provided by the invention, the thickness difference between the functional layer and the pole lug is reduced by increasing the thickness of the functional layer in the second area, so that the uniformity of the thickness of the pole piece is improved, and the cycle performance of the battery is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it will be obvious that the drawings in the following description are some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort to a person skilled in the art.
FIG. 1 is a schematic view of a pole piece according to the prior art;
FIG. 2 is a schematic structural diagram of a pole piece according to an embodiment of the present invention;
FIG. 3 is a schematic view illustrating a partition of a first surface of a current collector according to an embodiment of the present invention;
FIG. 4 is a schematic view illustrating a partition of a second surface of a current collector according to an embodiment of the present invention;
FIG. 5 is a schematic view of a pole piece according to another embodiment of the present invention;
fig. 6 is a schematic view illustrating a partition of a first surface of a current collector according to still another embodiment of the present invention;
fig. 7 is a schematic view illustrating a partition of a second surface of a current collector according to still another embodiment of the present invention;
FIG. 8 is a schematic view of a pole piece according to another embodiment of the present invention;
FIG. 9 is a schematic view of a pole piece according to another embodiment of the present invention;
fig. 10 is a schematic view illustrating a partition of a second surface of a current collector according to still another embodiment of the present invention;
FIG. 11 is a schematic cross-sectional view of a first side edge according to another embodiment of the present invention;
FIG. 12 is a schematic structural diagram of a functional layer according to another embodiment of the present invention;
FIG. 13 is a physical diagram of a tab bonding area according to an embodiment of the present invention;
FIG. 14 is an EDS spectrum of a cross-section of a pole piece near a first side edge provided in an embodiment of the present invention;
FIG. 15 is an EDS spectrum of a cross-section of a pole piece near a second side edge according to an embodiment of the present invention;
FIG. 16 is an EDS spectrum of a cross-section of a pole piece near a third side edge according to an embodiment of the present invention;
fig. 17 is an SEM image of a cross section of a tab weld area according to an embodiment of the present invention.
Reference numerals illustrate:
1-a current collector;
a-a first surface;
b-a second surface;
111-a first coating zone;
112-a first empty foil area;
121-a second coating zone;
1211-a first region;
1212-a second region;
c-a first side;
d-a second side;
e-a third side;
122-a second empty foil area;
2-a functional layer;
21-a protective layer;
22-active material layer;
3-pole lugs.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are 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.
The pole piece is an important component of a battery, fig. 1 is a schematic structural diagram of the pole piece provided by the prior art, and as shown in fig. 1, the pole piece comprises a current collector 1, a functional layer 2 and a pole lug 3, wherein the functional layer 2 is arranged on the surface of the current collector 1, and the thickness of the pole lug 3 is generally higher than that of the functional layer 2, and the pole lug glue is adhered to the surface of the pole lug 3, so that the pole piece is more complicated in structure and poorer in thickness uniformity, and the cycle performance of the battery is easily influenced; particularly, aiming at pole pieces in the pole lugs, how to adjust the pole piece structure and improve the cycle performance of the battery is a technical problem to be solved urgently by the technicians in the field.
To solve the above-mentioned technical problem, a first aspect of the present invention provides a pole piece, as shown in fig. 2 to 4, where the pole piece includes a current collector 1 and a functional layer 2, and the current collector 1 is used as a conductive substrate, and includes a first surface a and a second surface b that are oppositely disposed, where the first surface a includes a first coating area 111, and the second surface b includes a second coating area 121, and the functional layer 2 is disposed on the first coating area 111 and the second coating area 121 of the current collector 1.
According to the difference of the thickness of the functional layer 2 arranged on the second coating area 121, the second coating area 121 comprises a first area 1211 and a second area 1212, the projection of the first area 1211 on the current collector 1 coincides with the projection of the first coating area 111 on the current collector 1, the first area 1211 and the first coating area 111 form a double-sided coating area, namely, the upper surface and the lower surface of the current collector 1 are both provided with the functional layer 2; the projection of the second region 1212 onto the current collector 1 is located in a region outside the projection of the first coating region 111 onto the current collector 1, and the second region 1212 is a single-sided coating region, i.e. only one surface of the second region of the current collector 1 is provided with the functional layer 2.
Further, the second region 1212 is located on the side closer to the tab, and the first region 1211 is located on the side farther from the tab. For the pole piece in the pole lug, the second region 1212 is located at two sides of the pole lug, and the first region 1211 is located at one side of the second region 1212 away from the pole lug.
Those skilled in the art know that the pole piece is generally in a long sheet shape, the direction of the longer side is a length direction, the direction of the shorter side is a thickness direction, the direction of the side between the longer side and the shorter side is a width direction, and the length direction, the width direction and the thickness direction are perpendicular to each other. Referring to fig. 2 to 4, in the present invention, the x direction of the pole piece is the length direction of the pole piece, the z direction is the thickness direction of the pole piece, and the y direction is the width direction of the pole piece.
Along the thickness direction of the pole piece, the highest thickness of the functional layer 2 arranged in the first coating area 111 is W1, the lowest thickness of the functional layer 2 arranged in the first area 1211 is W2, the average thickness of the functional layer 2 arranged in the second area 1212 is W3, W3/(w1+w2) is more than or equal to 0.7, that is, the thickness of the functional layer in the single-sided coating area is not less than 70% of the total thickness of the functional layers in the double-sided coating area, by increasing the thickness of the functional layer in the second area, the difference of the heights of the functional layers and the pole lugs near the pole lugs is compensated, the uniformity of the thickness of the pole piece is improved, and the cycle performance of the battery is improved.
In the present invention, the highest thickness means the maximum value of the thickness of the functional layer 2 of the first coating region 111; the lowest thickness refers to the minimum value of the thickness of the functional layer 2 disposed in the first region 1211, and the average thickness refers to the average value of the thickness of the functional layer 2 disposed in the second region 1212.
In the pole piece preparation process, functional layer slurry is prepared first and coated on different areas of a current collector according to thickness requirements, then, the pole piece is rolled, in the rolling process, the functional layer 2 arranged in the second area 1212 of the current collector 1 can downwards squeeze the current collector 1, so that the second area 1212 is downwards recessed towards the direction of the first coating area 111, a recessed part is formed in the current collector 1, the space formed by the recessed part can accommodate the functional layer 2 of the second area 1212, the surface of the functional layer 2, far away from the current collector 1, is positioned on the same plane, and the flatness of the pole piece is ensured.
With continued reference to fig. 2, as the second region 1212 is recessed, at least a portion of the first region 1211 is bent in a direction toward the first coating region 111 and forms a bent portion, which is connected to the second region 1212.
Further, with continued reference to fig. 2, along the z-direction of the pole piece, the minimum value of the thickness of the functional layer 2 located on the bent portion of the second surface b is equal to W2, and the maximum value is equal to W3; the minimum value of the thickness of the functional layer 2 on the bending part of the first surface a is 0, and the maximum value is equal to W1. That is, the thickness of the functional layer 2 disposed at the bent portion of the second surface b gradually increases, and the thickness of the functional layer 2 disposed at the bent portion of the first surface a gradually decreases along the length direction of the current collector 1; the thickness of the functional layer in the bending area is changed, so that the uniformity of the thickness of the pole piece is improved, and the cycle performance of the battery is improved.
With continued reference to fig. 3 to 4, the first surface a of the current collector 1 further includes a first empty foil region 112, and the second surface b further includes a second empty foil region 122, where the first empty foil region 112 or the second empty foil region 122 is used for connecting the tab 3.
Further, the projection of the second empty foil region 122 onto the current collector 1 is within the projection of the first empty foil region 112 onto the current collector 1, i.e. the length of the first empty foil region 112 is greater than the length of the second empty foil region 122.
Further, the total area of the second empty foil region 122 and the second region 1212 is not greater than the area of the first empty foil region 112. Further, the area of the second region 1212 is 10% -100% of the area of the first empty foil region 112.
When the area of the second region 1212 is 100% of the area of the first empty foil region 112, the structure is as shown in fig. 5 to 7, and it can be seen that the second surface b of the current collector 1 does not include the second empty foil region, i.e. the regions corresponding to the first empty foil region 112 are all coated with the functional layer 2, which is helpful for improving the coating area of the functional layer and improving the energy density of the battery.
As shown in fig. 8, the pole piece provided by the invention further comprises a pole lug 3, one end of the pole lug 3 is connected with the surface of the current collector 1, the other end extends outwards along the y direction, and the pole lug 3 is arranged in the first empty foil area 112 or the second empty foil area 122. According to different types of pole pieces, different materials can be selected as the current collector 1 and the pole lug 3, for example, an aluminum foil can be adopted as the positive pole piece, a copper foil can be selected as the current collector for the negative pole piece, and the manufacturing materials of the pole lug 3 are different according to different types of pole pieces and can be metal materials such as copper, nickel and aluminum.
Further, in order to facilitate preparation of the pole piece, the distance between the functional layer 2 and the pole lug 3 along the x direction of the pole piece is 0.5-4 mm.
In a specific embodiment, the functional layer 2 includes a protective layer 21 and an active material layer 22, where the protective layer 21 and the active material layer 22 are sequentially stacked on the surface of the current collector 1, and the arrangement of the protective layer 21 helps to reduce the short circuit probability between the current collector and the pole piece, and improve the safety of the battery. Based on the current coating process, the distances between the protective layer 21 and the active material layer 22 and the tab 3 cannot be completely consistent, and there are cases where the protective layer 21 exceeds the active material layer 22 or where the active material layer 22 exceeds the protective layer 21, however, both cases are not beneficial to the improvement of the battery performance; specifically, when the protective layer 21 exceeds the active material layer 22, the thickness of the exceeding area is reduced compared with other areas, and in the hot press molding process, the stress of the area is insufficient, so that the interface contact between the pole piece and the diaphragm in the area is not firm, and in the cyclic charge and discharge process of the battery, the migration of ions is influenced, so that the ions are separated out after the battery is cycled for a certain number of times, and the capacity loss is caused; when the active material layer 22 exceeds the protective layer 21, the region is in direct contact with the current collector, electrons in the region are directly conducted to the active material layer by the current collector, and compared with the case that electrons in most regions of the electrode plates are conducted to the protective layer by the current collector and then conducted to the active material layer, electrons in the region are conducted more rapidly, ions are more favorable to be separated out in the charging process, positive electrode dynamics of the region are better, so that ion embedding pressure of the corresponding electrode plates is increased, ion separation risk of the corresponding negative electrode of the region is increased compared with that of the negative electrode of other regions, and the cycle stability of the battery is affected.
For the above reasons, the present invention keeps the edges of the protective layer 21 and the active material layer 22 close to the tab 3 as uniform as possible, and specifically, the distances between the protective layer 21 and the active material layer 22 and the tab 3 differ by not more than 0.5mm.
Further, the distance D2 between the protective layer 21 and the tab 3 is smaller than the distance D1 between the active material layer 22 and the tab 3, and the distance difference (D1-D2) between the protective layer and the active material layer and the tab is not greater than 0.1mm.
In one embodiment, as shown in fig. 9 to 12, when the width of the second empty foil region 122 is smaller than the width of the current collector 1, the second region 1212 includes a first side c, a second side d, and a third side e, and the first side c, the second side d, and the third side e form the second empty foil region 122 for placing the tab 3;
the distance between the protective layer 21 and the active material layer 22 and the first side c is D3, the distance between the protective layer 21 and the active material layer 22 and the second side D is D4, the distance between the protective layer 21 and the active material layer 22 and the third side e is D5, D3 > D4, and D3 > D5. That is, the length of the exposed protective layer 21 below the tab is greater than the length of the exposed protective layers on both sides of the tab, and the lengths D4 and D5 of the exposed protective layers on both sides of the tab may be the same or different.
Further, in order to avoid wrinkles in the tab connection area caused by deformation in different directions, the flatness of the pole piece is improved, and the flatness of the first side c is better than that of the second side d and the third side e. With continued reference to fig. 9 and 11, along the y-direction of the pole piece, the height difference of the current collectors 1 located at two sides of the first side c is H1; along the length direction of the pole piece, the height difference of the current collectors 1 positioned at the two sides of the second side edge d is H2, the height difference of the current collectors 1 positioned at the two sides of the third side edge e is H3, H1 is less than H2, and H1 is less than H3.
In one embodiment, the protective layer 21 includes inorganic particles and a binder, wherein the inorganic particles are a material that does not contain active lithium, including at least one of an insulating material and a conductive material; the insulating material is selected from one or more of aluminum oxide, magnesium oxide, titanium oxide, zinc oxide, silicon oxide, boehmite, cobalt oxide, ferric phosphate, aluminum phosphate, ferric metaphosphate and aluminum metaphosphate; the conductive material is at least one selected from ATO (Sb-doped SnO 2), FTO (F-doped SnO 2), ITO (Sn-doped In2O 3) and AZO (Al-doped ZnO), or at least one selected from alumina, magnesia, titanium oxide, zinc oxide, silicon oxide, boehmite, cobalt oxide, ferric phosphate, aluminum phosphate, ferric metaphosphate, aluminum metaphosphate, lithium iron phosphate, nickel cobalt lithium manganate, lithium cobalt oxide and lithium titanate which are coated by at least one material selected from carbon black, carbon nano tube, graphene and ATO, FTO, ITO, AZO.
Further, when the inorganic particles of the protective layer are selected from insulating materials, the protective layer further includes a conductive agent. Still further, the inorganic particles are preferably conductive materials.
The binder comprises one or more of polyvinylidene fluoride (PVDF), acrylic modified PVDF, polyacrylate polymer, polyimide, styrene-butadiene rubber and styrene-acrylic rubber.
The active material layer 22 includes an active material, a conductive agent, and a binder, and the active material may be selected according to the type of the electrode sheet, for example, when the electrode sheet is a positive electrode sheet, the positive electrode active material is a lithium-containing transition metal oxide such as one or more of lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium iron phosphate, lithium manganate, and lithium-rich manganese-based materials; when the pole piece is a negative pole piece, the negative pole active substance is one or more of silicon, silicon carbon, siOx (0 < X < 2), lithium silicon alloy, artificial graphite, natural graphite, hard carbon, soft carbon and mesophase carbon microspheres.
In general, the thickness of the protective layer 21 is 1/20 to 1/5 of the thickness of the active material layer 22.
The preparation method of the pole piece provided by the invention comprises the following steps: firstly, preparing protective layer slurry and active material layer slurry, coating the protective layer slurry and the active material layer slurry on the surface of a current collector, and drying to obtain a functional layer; and secondly, removing the functional layer to form a first empty foil area and a second empty foil area, wherein the binding force between the protective layer and the current collector after NMP spraying is less than 100N/m in order to completely remove the protective layer and the active substance layer from the current collector. In order to meet the requirements, the formula of the protective layer is specially limited, the content of the binder is not more than 8%, otherwise, the binding property between the functional layer and the current collector is good, and the functional layer and the current collector are difficult to thoroughly clean; and finally, welding a tab on the first empty foil area or the second empty foil area, and pasting tab gummed paper to obtain the pole piece.
The pole piece structure provided by the invention is suitable for the positive pole piece and/or the negative pole piece, and can be set according to actual needs.
A second aspect of the invention provides a battery comprising a pole piece as described in any one of the preceding claims.
Based on the uniformity of the thickness of the pole piece provided by the first aspect of the invention, the battery comprising the pole piece has better cycle performance.
The preparation method of the battery provided by the invention can be prepared according to a conventional method in the field.
In a specific embodiment, firstly, according to the pole piece structure, a positive pole piece and a negative pole piece are prepared, a battery core is prepared by matching with a diaphragm, and secondly, the battery core is packaged and injected with liquid to prepare the battery.
The diaphragm and the electrolyte are all conventional materials in the field, and can be specifically set according to the needs.
The technical scheme provided by the invention is further described below by combining specific embodiments.
Example 1
The pole piece provided in this embodiment is a positive pole piece, and its structure is as shown in fig. 9, including a current collector aluminum foil, a protective layer, a positive active material layer and a tab, specifically:
the current collector comprises a first surface and a second surface, the first surface comprises a first empty foil area and a first coating area, the size of the first empty foil area is 11mm along the x direction of the pole piece, and the size of the first empty foil area is 20mm along the y direction of the pole piece; the second surface comprises a second empty foil area and a second coating area, the size of the second empty foil area is 10mm along the x direction of the pole piece, and the size of the second empty foil area is 20mm along the y direction of the pole piece;
a protective layer and a positive electrode active material layer are sequentially arranged on the first coating area and the second coating area, wherein the protective layer comprises 92 parts by mass of ATO coated TiO2 and 8 parts by mass of binder PVDF; the positive electrode active material layer includes 96 parts by mass of lithium cobaltate, 1 part by mass of carbon black, 1 part by mass of carbon nanotubes, and 2 parts by mass of a binder PVDF.
The total thickness of the protective layer and the positive electrode active material layer on the first coating region was 70 μm, and the second coating region included a first region and a second region, the thickness of which was 60 μm, and the ratio of the two was 85.7%.
The second empty foil area is connected with a positive electrode lug, the distance between the protective layer and the positive electrode lug is smaller than the distance between the positive electrode active material layer and the positive electrode lug, and the distance difference D1-D2 between the protective layer and the positive electrode lug is smaller than 0.1mm.
The preparation method of the pole piece provided by the embodiment comprises the following steps:
step 1, preparing protective layer slurry and positive electrode active material layer slurry: 92 parts by mass of ATO-coated TiO2 and 8 parts by mass of PVDF are mixed, a certain amount of NMP is added, the solid content of the slurry is adjusted to 40%, and the slurry is stirred to prepare the slurry for the protective layer. 96 parts by mass of lithium cobaltate, 1 part by mass of carbon black, 1 part by mass of carbon nanotube and 2 parts by mass of PVDF are mixed, a certain amount of NMP is added, the solid content of the slurry is adjusted to 70%, and the slurry of the positive electrode active material layer is prepared by stirring.
And 2, coating the protective layer slurry prepared in the step 1 on a positive electrode current collector, coating the positive electrode active material layer slurry on the protective layer, and drying to obtain the positive electrode plate.
Step 3, removing part of the active material layer and the protective layer of the positive electrode plate by using a scraper (NMP needs to be sprayed before removing), wherein the removal size of the first surface is 20mm by 11mm, and a first empty foil area is obtained; the second surface has a clear dimension of 20 x 10mm, resulting in a second empty foil area.
And 4, welding a positive electrode lug on the second empty foil area, and attaching protective gummed paper. And respectively rolling the positive pole piece to the designed thickness by using a roller press.
Fig. 13 is a physical diagram of a tab welding area according to an embodiment of the present invention, as shown in fig. 13, the tab welding area is a rectangular blank foil, and three sides are adjacent to the functional layer. Fig. 14 to 16 are EDS patterns of the cross section of the tab lands, wherein orange represents the active material layer, blue represents the protective layer, yellow represents aluminum, and aluminum foil. It can be seen that the protective layer is slightly more than the active material layer by a length of < 0.1mm. And compared with the second side and the third side which are positioned at two sides of the tab and shown in fig. 15-16, the first side shown in fig. 14 has more exposed protective layers, and the current collector is smoother.
FIG. 17 is an SEM image of a cross section of a tab weld zone, as shown in FIG. 17, having a single-sided coating zone thickness of 60 μm, a double-sided coating zone thickness of 70 μm, and a single-sided zone to double-sided zone thickness ratio of 85.7%.
Example 2
The positive electrode sheet provided in this embodiment can refer to embodiment 1, and is different in that the distance between the protective layer and the positive electrode tab is smaller than the distance between the positive electrode active material layer and the positive electrode tab, and the difference between the distances is less than 0.5mm.
Example 3
The positive electrode sheet provided in this embodiment can refer to embodiment 1, and is different in that the distance between the protective layer and the positive electrode tab is smaller than the distance between the positive electrode active material layer and the positive electrode tab, and the difference between the distances is less than 0.3mm.
Example 4
The positive electrode sheet provided in this embodiment can refer to embodiment 1, and is different in that the distance between the protective layer and the positive electrode tab is smaller than the distance between the positive electrode active material layer and the positive electrode tab, and the difference between the distances is 0mm.
Example 5
The positive electrode sheet provided in this embodiment may refer to embodiment 1, and is different in that the removal dimension of the first surface is 20×12mm, that is, the dimension of the first empty foil area is 12mm along the length direction, and the dimension of the first empty foil area is 20mm along the width direction.
Example 6
The positive electrode sheet provided in this embodiment may refer to embodiment 1, and is different in that the removal dimension of the first surface is 20×13mm, that is, the dimension of the first empty foil area is 13mm along the length direction, and the dimension of the first empty foil area is 20mm along the width direction.
Example 7
The positive electrode sheet provided in this embodiment may refer to embodiment 1, and is different in that the removal dimension of the first surface is 20×14mm, that is, the length of the first empty foil area is 14mm along the length direction, and the dimension of the first empty foil area is 20mm along the width direction.
Example 8
The structure of the positive electrode sheet provided in this embodiment is shown in fig. 5, that is, the first surface includes a first empty foil area and a first coating area, the second surface includes a second coating area, the second empty foil area is not included, the size of the first empty foil area is 10mm along the length direction, and the size of the first empty foil area is 20mm along the width direction.
Example 9
The positive electrode sheet according to this embodiment is different from that according to embodiment 1 in that the total thickness of the protective layer and the positive electrode active material layer on the first coating region is 70 μm, the second coating region includes a first region and a second region, the thickness of the second region is 49 μm, and the ratio W1/W2 of the two is 70%.
Example 10
The positive electrode sheet according to this example was provided with reference to example 1, except that the total thickness of the protective layer and the positive electrode active material layer on the first coating region was 70 μm, and the second coating region included a first region and a second region, the thickness of the second region being 63 μm, and the ratio of the two was 90%.
Comparative example 1
The positive electrode sheet provided in this comparative example can refer to example 1, and is different in that the distance between the protective layer and the positive electrode tab is smaller than the distance between the positive electrode active material layer and the positive electrode tab, and the difference between the distances is 2.5-3 mm.
The manufacturing process can refer to example 1, except that the protective layer slurry was coated on the positive electrode current collector by a gravure coater, wherein the gravure roll reserved the tab position, the protective layer was not coated at the tab welding position, wherein the size of the uncoated region in the length direction of the pole piece was 16mm, and the size in the width direction of the pole piece was 20mm. And coating the positive electrode active material in the second step on the protective layer, and drying to obtain the positive electrode plate.
The first surface of the positive current collector is cleaned to form a first empty foil area with the thickness of 20mm by 11mm, and the second surface is cleaned to form a second empty foil area with the thickness of 20mm by 10mm, namely, the distance between the protective layer and the positive electrode lug is smaller than the distance between the positive electrode active material layer and the positive electrode lug on the first surface, the distance between the protective layer and the positive electrode lug is 2.5mm, the distance between the protective layer and the positive electrode lug is smaller than the distance between the positive electrode active material layer and the positive electrode lug on the second surface, and the distance between the protective layer and the positive electrode lug is 3mm.
Comparative example 2
The positive electrode sheet provided in this comparative example can be referred to example 1, except that the first empty foil region and the second empty foil region each have a size of 11mm in the length direction of the sheet, and the second coating region corresponds to the first coating region, i.e., the second coating region does not include the second region.
Comparative example 3
The positive electrode sheet provided in this comparative example was referred to example 1, except that the first empty foil region was 25mm in size along the length of the sheet.
Comparative example 4
The positive electrode sheet according to this example was provided with reference to example 1, except that the total thickness of the protective layer and the positive electrode active material layer on the first coating region was 70 μm, and the second coating region included a first region and a second region, the thickness of the second region being 40 μm, and the ratio of the two was 57%.
The positive electrode plates provided in examples 1-10 and comparative examples 1-4 are matched with the negative electrode plates and the diaphragms, the battery cells are prepared through a winding process, and the battery cells are packaged, injected with liquid, formed, separated and the like through an aluminum plastic film to prepare the lithium ion battery; the negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer arranged on the surface of the negative electrode current collector, wherein the negative electrode active material layer comprises 96 parts by mass of artificial graphite, 1 part by mass of carbon black, 1.5 parts by mass of styrene-butadiene rubber and 1.5 parts by mass of sodium carboxymethyl cellulose.
The prepared lithium ion battery is subjected to cyclic capacity retention rate and energy density test, the test method is as follows, and the test results are shown in table 1:
25 ℃ cycle capacity retention test: the battery was charged and discharged at 25 ℃ at a rate of 1.5C charge/0.5C discharge, and the ratio of the discharge capacity at 1000 th time to the discharge capacity at the first time was tested.
Energy density testing: the battery was charged at 0.2C and discharged to 3.0V at 0.2C, the energy of the discharge was recorded, denoted as E, and the energy density was ed=e/(l×w×h), wherein L, W, H is the length, width and height of the battery.
TABLE 1
As is clear from the data provided in examples 1 to 4 and comparative example 1, as the distance difference between the protective layer and the positive electrode active material layer and the tab increases, the cycle performance of the battery becomes worse, and therefore, the distance difference between the protective layer and the active material layer and the tab should be not more than 0.5mm, and further not more than 0.1mm.
According to the data provided in examples 1, 5-7 and comparative example 2, a single-sided area exists near the tab, and the tab is bent towards the empty foil due to the existence of the single-sided area, so that the empty foil area has a larger space for accommodating the tab, the interface stability of the tab welding area and the adjacent coating is improved, and the cycle capacity retention rate of the battery is improved.
According to the data provided in examples 8 and 1, the second surface is not provided with a hollow foil area, and the hollow foil area is not protected by the tab gummed paper, so that the thickness of the pole piece is reduced, the coverage area of the positive electrode active material layer is increased, and the energy density of the battery is improved.
According to the data provided in examples 9 to 10 and comparative example 4, by increasing the thickness of the functional layers on both sides of the tab and making the thickness of the functional layer in the second region greater than 70% of the total thickness in the other regions, it is possible to improve the uniformity of the thickness of the pole piece, make the interface more stable, and increase the cycle capacity retention rate of the battery.
In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element in question must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.
The terms first and second in the description and claims of the invention and in the description of the figures above are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the invention described herein may be capable of operation in sequences other than those illustrated or otherwise described.
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 (9)
1. Pole piece, characterized by comprising a current collector (1) and a functional layer (2), wherein the current collector (1) comprises a first surface (a) and a second surface (b) which are oppositely arranged, the first surface (a) comprises a first coating area (111) and a first empty foil area (112), the second surface (b) comprises a second coating area (121) and a second empty foil area (122), and the functional layer (2) is arranged on the first coating area (111) and the second coating area (121) of the current collector (1);
the second coating region (121) comprises a first region (1211) and a second region (1212), wherein the projection of the first region (1211) on the current collector (1) coincides with the projection of the first coating region (111) on the current collector (1), and the projection of the second region (1212) on the current collector (1) is located in a region outside the projection of the first coating region (111) on the current collector (1);
the highest thickness of the functional layer (2) arranged in the first coating area (111) is W1, the lowest thickness of the functional layer (2) arranged in the first area (1211) is W2, and the average thickness of the functional layer (2) arranged in the second area (1212) is W3, wherein W3/(W1+W2) is more than or equal to 0.7;
the second empty foil region (122) is connected with a tab (3), the second region (1212) is positioned at one side close to the tab, and the first region (1211) is positioned at one side far away from the tab;
at least part of the first region (1211) is bent in a direction toward the first application region (111) and forms a bent portion, which is connected to the second region (1212);
the minimum value of the thickness of the functional layer (2) positioned on the bending part of the second surface (b) is equal to W2, the maximum value is equal to W3 along the thickness direction of the pole piece, and the thickness of the functional layer (2) arranged on the bending part of the second surface (b) is gradually increased along the length direction of the current collector (1);
the minimum value of the thickness of the functional layer (2) positioned on the bending part of the first surface (a) is 0 along the thickness direction of the pole piece, the maximum value is equal to W1, and the thickness of the functional layer (2) arranged on the bending part of the first surface (a) gradually decreases along the length direction of the current collector (1).
2. Pole piece according to claim 1, characterized in that the projection of the second empty foil area (122) onto the current collector (1) is located within the projection of the first empty foil area (112) onto the current collector (1).
3. The pole piece of claim 2, wherein the total area of the second empty foil region (122) and second region (1212) is not greater than the area of the first empty foil region (112).
4. A pole piece according to claim 3, characterized in that the area of the second region (1212) is 10% -100% of the area of the first empty foil region (112).
5. The pole piece according to any one of claims 1 to 4, wherein the functional layer (2) comprises a protective layer (21) and an active material layer (22), and the protective layer (21) and the active material layer (22) are sequentially stacked on the surface of the current collector (1);
along the length direction of the pole piece, the distance between the active material layer (22) and the pole lug (3) is D1, and the distance between the protective layer (21) and the pole lug (3) is D2, wherein |D1-D2| is less than or equal to 0.5mm.
6. Pole piece according to claim 5, characterized in that the distance D2 of the protective layer (21) from the pole lug (3) is smaller than the distance D1 of the active substance layer (22) from the pole lug (3), (D1-D2) is less than or equal to 0.1mm.
7. The pole piece of claim 6, wherein the second region (1212) comprises a first side (c), a second side (d), and a third side (e), the first side (c), the second side (d), and the third side (e) forming a tab connection region;
the distance difference between the protective layer (21) and the active material layer (22) and the first side (c) is D3, the distance difference between the protective layer (21) and the active material layer (22) and the second side (D) is D4, and the distance difference between the protective layer (21) and the active material layer (22) and the third side (e) is D5, D3 > D4, and D3 > D5.
8. Pole piece according to claim 7, characterized in that the height difference of the current collectors (1) on both sides of the first side (c) in the pole piece width direction is H1; along the length direction of the pole piece, the height difference of the current collectors (1) positioned at the two sides of the second side edge (d) is H2, the height difference of the current collectors (1) positioned at the two sides of the third side edge (e) is H3, H1 is less than H2, and H1 is less than H3.
9. A battery comprising a pole piece according to any one of claims 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311713765.5A CN117423799B (en) | 2023-12-14 | 2023-12-14 | Pole piece and battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311713765.5A CN117423799B (en) | 2023-12-14 | 2023-12-14 | Pole piece and battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN117423799A CN117423799A (en) | 2024-01-19 |
| CN117423799B true CN117423799B (en) | 2024-03-19 |
Family
ID=89526903
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311713765.5A Active CN117423799B (en) | 2023-12-14 | 2023-12-14 | Pole piece and battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117423799B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005183181A (en) * | 2003-12-19 | 2005-07-07 | Dainippon Ink & Chem Inc | Electrode plate for nonaqueous electrolyte secondary battery and manufacturing method of the same |
| CN105742565A (en) * | 2016-02-29 | 2016-07-06 | 宁德新能源科技有限公司 | Lithium ion battery pole plate and preparation method thereof |
| WO2021223655A1 (en) * | 2020-05-08 | 2021-11-11 | 珠海冠宇电池股份有限公司 | Positive electrode plate, preparation method therefor, and lithium ion battery comprising same |
| CN216120370U (en) * | 2021-10-19 | 2022-03-22 | 厦门海辰新能源科技有限公司 | Secondary battery's electric core and secondary battery |
| CN115332480A (en) * | 2022-10-13 | 2022-11-11 | 宁德新能源科技有限公司 | Pole piece, electrochemical device and electronic equipment |
| CN218647976U (en) * | 2022-10-20 | 2023-03-17 | 珠海冠宇电池股份有限公司 | Electrode assembly and battery |
-
2023
- 2023-12-14 CN CN202311713765.5A patent/CN117423799B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005183181A (en) * | 2003-12-19 | 2005-07-07 | Dainippon Ink & Chem Inc | Electrode plate for nonaqueous electrolyte secondary battery and manufacturing method of the same |
| CN105742565A (en) * | 2016-02-29 | 2016-07-06 | 宁德新能源科技有限公司 | Lithium ion battery pole plate and preparation method thereof |
| WO2021223655A1 (en) * | 2020-05-08 | 2021-11-11 | 珠海冠宇电池股份有限公司 | Positive electrode plate, preparation method therefor, and lithium ion battery comprising same |
| CN216120370U (en) * | 2021-10-19 | 2022-03-22 | 厦门海辰新能源科技有限公司 | Secondary battery's electric core and secondary battery |
| CN115332480A (en) * | 2022-10-13 | 2022-11-11 | 宁德新能源科技有限公司 | Pole piece, electrochemical device and electronic equipment |
| CN218647976U (en) * | 2022-10-20 | 2023-03-17 | 珠海冠宇电池股份有限公司 | Electrode assembly and battery |
Also Published As
| Publication number | Publication date |
|---|---|
| CN117423799A (en) | 2024-01-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111540880B (en) | Negative plate, preparation method and lithium ion battery comprising negative plate | |
| WO2011142083A1 (en) | Electrode for lithium ion secondary battery and method for producing same | |
| WO2021174689A1 (en) | All-solid-state battery and preparation method therefor | |
| US11876171B2 (en) | All-solid-state battery and production method of the same | |
| JPH1173947A (en) | Electrode for battery and its manufacture | |
| JP2003059486A (en) | Stacked type battery and its manufacturing method | |
| CN112234212A (en) | Positive pole piece and lithium ion battery comprising same | |
| JP2001015146A (en) | Battery | |
| CN115295767A (en) | Positive plate and lithium ion battery | |
| JP7278090B2 (en) | All-solid lithium secondary battery and manufacturing method thereof | |
| JP2003031224A (en) | Light-weight current collector for secondary battery | |
| JP4636920B2 (en) | Battery with spiral electrode | |
| CN111900412B (en) | Flexible current collector, lithium ion battery pole piece and preparation method thereof | |
| CN117423799B (en) | Pole piece and battery | |
| JP7246196B2 (en) | All-solid lithium secondary battery | |
| JP7201085B2 (en) | solid state battery | |
| WO2013031213A1 (en) | Electrode plate for non-aqueous secondary battery and non-aqueous secondary battery using same | |
| SE545847C2 (en) | Anode fabrication by pattern lamination | |
| CN115842091A (en) | Battery pole piece, battery core, battery module, battery pack and electric device | |
| WO2019181097A1 (en) | Solid-state battery | |
| CN113097453A (en) | Lithium pre-embedding method for positive electrode of lithium ion battery | |
| TW201946317A (en) | Gap section multilayer electrode profile | |
| CN219832703U (en) | Coating current collector, pole piece and lithium battery | |
| JP7243704B2 (en) | All-solid secondary battery | |
| CN219642868U (en) | Battery current collector and lithium battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |