CN116565211B - Negative plate, energy storage device and electric equipment - Google Patents
Negative plate, energy storage device and electric equipment Download PDFInfo
- Publication number
- CN116565211B CN116565211B CN202310834599.8A CN202310834599A CN116565211B CN 116565211 B CN116565211 B CN 116565211B CN 202310834599 A CN202310834599 A CN 202310834599A CN 116565211 B CN116565211 B CN 116565211B
- Authority
- CN
- China
- Prior art keywords
- negative electrode
- active layer
- conductive agent
- electrode active
- satisfies
- 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
- 238000004146 energy storage Methods 0.000 title claims abstract description 23
- 239000006258 conductive agent Substances 0.000 claims abstract description 143
- 238000010521 absorption reaction Methods 0.000 claims abstract description 38
- 239000000843 powder Substances 0.000 claims abstract description 31
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 36
- 239000003921 oil Substances 0.000 claims description 27
- 239000002041 carbon nanotube Substances 0.000 claims description 16
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 16
- 239000007773 negative electrode material Substances 0.000 claims description 15
- 229910021389 graphene Inorganic materials 0.000 claims description 13
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 11
- 229910052744 lithium Inorganic materials 0.000 claims description 11
- 229910002804 graphite Inorganic materials 0.000 claims description 6
- 239000010439 graphite Substances 0.000 claims description 6
- 239000003273 ketjen black Substances 0.000 claims description 5
- 239000002134 carbon nanofiber Substances 0.000 claims description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical class C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- 229910021385 hard carbon Inorganic materials 0.000 claims description 3
- 239000002210 silicon-based material Substances 0.000 claims description 3
- 229910021384 soft carbon Inorganic materials 0.000 claims description 3
- 239000010410 layer Substances 0.000 description 120
- 239000002002 slurry Substances 0.000 description 30
- 229910001416 lithium ion Inorganic materials 0.000 description 22
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 21
- 230000000052 comparative effect Effects 0.000 description 12
- 239000006185 dispersion Substances 0.000 description 12
- 239000007788 liquid Substances 0.000 description 10
- 239000003792 electrolyte Substances 0.000 description 9
- 239000000203 mixture Substances 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- 238000012360 testing method Methods 0.000 description 8
- 239000011248 coating agent Substances 0.000 description 7
- 238000000576 coating method Methods 0.000 description 7
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 6
- 229920002125 Sokalan® Polymers 0.000 description 6
- 239000006183 anode active material Substances 0.000 description 6
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 6
- 230000006872 improvement Effects 0.000 description 6
- 230000008595 infiltration Effects 0.000 description 6
- 238000001764 infiltration Methods 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 238000001035 drying Methods 0.000 description 5
- 239000011888 foil Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000011230 binding agent Substances 0.000 description 4
- 230000014759 maintenance of location Effects 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- 229910021383 artificial graphite Inorganic materials 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 239000001768 carboxy methyl cellulose Substances 0.000 description 3
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 3
- 239000004584 polyacrylic acid Substances 0.000 description 3
- 239000007774 positive electrode material Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000002562 thickening agent Substances 0.000 description 3
- FFRBMBIXVSCUFS-UHFFFAOYSA-N 2,4-dinitro-1-naphthol Chemical compound C1=CC=C2C(O)=C([N+]([O-])=O)C=C([N+]([O-])=O)C2=C1 FFRBMBIXVSCUFS-UHFFFAOYSA-N 0.000 description 2
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 description 2
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 2
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 239000006182 cathode active material Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000011267 electrode slurry Substances 0.000 description 2
- 230000002349 favourable effect Effects 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
- 239000002245 particle Substances 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 238000004513 sizing Methods 0.000 description 2
- 238000002791 soaking Methods 0.000 description 2
- 239000011800 void material Substances 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- 229910010710 LiFePO Inorganic materials 0.000 description 1
- 229910013872 LiPF Inorganic materials 0.000 description 1
- 101150058243 Lipf gene Proteins 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
- 239000013543 active substance Substances 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000006256 anode slurry Substances 0.000 description 1
- XKRFYHLGVUSROY-UHFFFAOYSA-N argon Substances [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- -1 argon ion Chemical class 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006257 cathode slurry Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000013256 coordination polymer Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007607 die coating method Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000002355 dual-layer Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000005087 graphitization Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 1
- 229910003002 lithium salt Inorganic materials 0.000 description 1
- 159000000002 lithium salts Chemical class 0.000 description 1
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002048 multi walled nanotube Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000002109 single walled nanotube Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000009461 vacuum packaging Methods 0.000 description 1
- 238000004804 winding Methods 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
-
- 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
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
- H01M4/366—Composites as layered products
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Composite Materials (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The application relates to a negative plate, an energy storage device and electric equipment. The negative electrode plate comprises a current collector, and a first negative electrode active layer and a second negative electrode active layer which are sequentially arranged on the surface of the current collector. The first negative electrode active layer and the second negative electrode active layer each independently contain a conductive agent, and the conductive agent in each negative electrode active layer accounts for the same mass percentage of the total mass of each negative electrode active layer. The conductive agent comprises a first conductive agent and a second conductive agent; the powder conductivity of the first conductive agent is less than the powder conductivity of the second conductive agent; the oil absorption value of the second conductive agent is smaller than that of the first conductive agent. The percentage of the second conductive agent in the total content of the conductive agents in the first negative electrode active layer is recorded as X1, and the percentage of the second conductive agent in the total content of the conductive agents in the second negative electrode active layer is recorded as X2; the negative electrode sheet satisfies: x1 > X2; the difference between the thickness D1 of the first negative electrode active layer and the thickness D2 of the second negative electrode active layer is 0.02-0.1 mm.
Description
Technical Field
The application relates to the technical field of energy storage, in particular to a negative plate, an energy storage device and electric equipment.
Background
With the development of electric vehicles, large-scale energy storage systems and other fields, higher and higher requirements are put on the energy density of the energy storage device in the market. However, the improvement of the energy density also causes the degradation of the dynamic performance of the battery, and from the technical aspect, perfect compatibility of the high energy density and the high dynamic performance is difficult to achieve.
Disclosure of Invention
Aiming at the problems, the application provides a negative plate, an energy storage device and electric equipment, wherein the negative plate has better liquid absorption capacity and better electronic conductivity, and is favorable for considering the energy density and the dynamic performance of a battery.
In one aspect of the present application, there is provided a negative electrode sheet comprising: a current collector, a first negative electrode active layer and a second negative electrode active layer which are sequentially arranged on the surface of the current collector;
the first negative electrode active layer and the second negative electrode active layer each independently contain a conductive agent, and in each negative electrode active layer, the conductive agent accounts for the same mass percentage of the total mass of each negative electrode active layer; wherein the conductive agent comprises a first conductive agent and a second conductive agent; the powder conductivity ρ1 of the first conductive agent is less than the powder conductivity of the second conductive agent; the oil absorption value K2 of the second conductive agent is smaller than the oil absorption value K1 of the first conductive agent;
in the first negative electrode active layer, the percentage of the second conductive agent accounting for the total content W1 of the first negative electrode active layer is denoted as X1, and the percentage of the second conductive agent accounting for the total content W2 of the second negative electrode active layer is denoted as X2; the negative electrode sheet satisfies: x1 > X2;
the difference between the thickness D1 of the first negative electrode active layer and the thickness D2 of the second negative electrode active layer is 0.02 mm-0.1 mm.
Through reasonable proportion of the thicknesses of the first negative electrode active layer and the second negative electrode active layer and the types of the conductive agents, the content of the second conductive agent with higher powder conductivity in the first negative electrode active layer close to the current collector is higher, the content of the first conductive agent with higher liquid absorption performance in the second negative electrode active layer correspondingly far away from the current collector is higher, the difference between the thickness D1 of the first negative electrode active layer and the thickness D2 of the second negative electrode active layer is controlled to be 0.02 mm-0.1 mm, and the two negative electrode active layers are both provided with more proper thicknesses; the second negative electrode active layer has better electrolyte infiltration performance, the contact resistance between the first negative electrode active layer and the current collector is smaller, the impedance of the negative electrode plate is reduced comprehensively, and the negative electrode plate can ensure better dynamic performance and better cycle stability and multiplying power performance under the condition of higher energy density.
In some embodiments, the first conductive agent comprises at least one of Super P, ketjen black, and conductive graphite. The first conductive agent has better liquid absorption capacity, and can improve electrolyte infiltration of the negative plate, thereby improving lithium ion transmission.
In some embodiments, the second conductive agent includes at least one of carbon nanotubes, carbon nanofibers, and graphene. Compared with the traditional conductive agent, the second conductive agent has excellent conductivity, and can improve the conductive network among particles, thereby improving the contact resistance between the active layer and the current collector and the resistance in the active layer and reducing the impedance of the negative plate.
In some embodiments, the sum of the thickness D1 of the first anode active layer and the thickness D2 of the second anode active layer is 0.05 mm to 0.2 mm. The sum of the thickness D1 of the first anode active layer and the thickness D2 of the second anode active layer is in the range, and the anode sheet can give consideration to better dynamic performance under the condition of ensuring higher energy density by controlling the composition ratio of the conductive agents of the first anode active layer and the second anode active layer.
In some of these embodiments, the surface density CW of the negative electrode active material in the negative electrode sheet satisfies: 5.2 g/mm 2 ＜CW＜15.2 g/mm 2 . The double-layer coated negative plate is particularly suitable for thick plates, and the energy density and the dynamic performance of the battery can be well considered under the condition that the surface density of the negative electrode active material is in the range. CW < 5.2 g/mm 2 The improvement of the kinetic properties of the negative electrode sheet by the double-coated negative electrode active layer is not significant when CW > 15.2 g/mm 2 When the negative plate has larger thickness, the improvement effect of the type and content of the conductive agent on the dynamic performance is not obvious.
In some of these embodiments, in the first anode active layer, the percentage Y1 of the first conductive agent to the total content W1 of the first anode active layer satisfies: y1 is more than or equal to 50 percent and less than 100 percent to 2.6 percent (CW-5.2). When Y1 is less than 50%, the second conductive agent in the first negative electrode active layer has an excessively large proportion, so that the dispersion of the slurry in the preparation process is easily influenced, and the preparation difficulty is increased. And at Y1 > 100% -2.6% (CW-5.2)%, the second conductive agent in the first anode active material layer is too low in proportion, and the conductivity of the first anode active layer decreases, resulting in an increase in the resistance of the battery.
In some of these embodiments, in the second anode active layer, the percentage Y2 of the first conductive agent to the total content W2 of the second anode active layer satisfies: 100% -2.6% (CW-5.2)% -Y2 is less than or equal to 100%. When Y2 is less than 100% -2.6% (CW-5.2)%, the first conductive agent in the second negative electrode active layer is too small, so that the liquid absorption capacity of the surface of the negative electrode sheet is reduced, the electrolyte infiltration capacity of the negative electrode sheet is poor, and the impedance of the battery is increased.
In some embodiments, the mass percentage of the conductive agent in each of the anode active layers is 0.2% -3%. The content of the conductive agent is controlled within the above range, the negative electrode sheet has good dynamic performance, and the energy density is not obviously reduced.
In some embodiments, in each of the negative electrode active layers, the mass percentage of the negative electrode active material is 90% -99.5%. The mass percentage of the anode active material is within the above range, and the anode sheet has a higher energy density.
In some embodiments, the negative active material of the negative electrode sheet includes at least one of graphite, soft carbon, hard carbon, a silicon-based material, and lithium titanate.
In some embodiments, the negative electrode sheet satisfies at least one condition of (1) to (4):
(1) The oil absorption value K1 of the first conductive agent satisfies the following conditions: 200 mL/100g K1 is less than or equal to 600mL/100 g;
(2) The oil absorption value K2 of the second conductive agent satisfies the following conditions: 150mL/100g K2 is less than or equal to 300mL/100 g;
(3) The powder conductivity ρ1 of the first conductive agent satisfies: 0.5 S/m is less than or equal to ρ1 and less than or equal to 20S/m;
(4) The powder conductivity ρ2 of the second conductive agent satisfies: 5S/m.ltoreq.ρ2.ltoreq.400S/m.
When the first conductive agent and the second conductive agent meet the oil absorption value and the powder conductivity, the first conductive agent has better liquid absorption capacity, and the second conductive agent has better electron conductivity, and the lithium ion transmission of the negative electrode plate can be optimized and the impedance of the battery can be reduced by reasonably adjusting the types of the conductive agents in the first negative electrode active layer and the second negative electrode active layer.
In a second aspect, the application further provides an energy storage device, which comprises the negative plate.
In a third aspect, the application further provides electric equipment, which comprises the energy storage device, wherein the energy storage device supplies power for the electric equipment.
Detailed Description
The present application will be described more fully hereinafter in order to facilitate an understanding of the present application. This application may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
Where the terms "comprising," "having," and "including" are used herein, it is intended to cover a non-exclusive inclusion, unless a specifically defined term is used, such as "consisting of … … only," etc., another component may be added.
The words "preferably," "more preferably," "more preferably," and the like, refer to embodiments of the application that may provide certain benefits in some instances. However, other embodiments may be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the application. That is, in the present application, "preferable", "more preferable", etc. are merely description of embodiments or examples that are more effective, but do not limit the scope of the present application.
In the present application, "further", "still further", "particularly" and the like are used for descriptive purposes to indicate differences in content but should not be construed as limiting the scope of the application.
In the present application, "at least one" means one or more, such as one, two or more. The meaning of "plural" or "several" means at least two, for example, two, three, etc., and the meaning of "multiple" means at least two, for example, two, three, etc., unless specifically defined otherwise. In the description of the present application, the meaning of "several" means at least one, such as one, two, etc., unless specifically defined otherwise.
When a range of values is disclosed herein, the range is considered to be continuous and includes both the minimum and maximum values for the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range description features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to include any and all subranges subsumed therein.
All steps of the present application may be performed sequentially or randomly unless otherwise specified. For example, the method comprises steps (a) and (b), meaning that the method may comprise steps (a) and (b) performed sequentially, or may comprise steps (b) and (a) performed sequentially. For example, the method may further comprise step (c), meaning that step (c) may be added to the method in any order, e.g., the method may comprise steps (a), (b) and (c), steps (a), (c) and (b), steps (c), (a) and (b), etc.
Unless mentioned to the contrary, singular terms may include plural and are not to be construed as being one in number.
In the present application, "above" or "below" includes the present number. E.g., 1 or less, including 1.
With the development of electric vehicles, large-scale energy storage systems and other fields, higher and higher requirements are put on the energy density of the energy storage device in the market. However, the improvement of the energy density also causes the degradation of the dynamic performance of the battery, and from the technical aspect, perfect compatibility of the high energy density and the high dynamic performance is difficult to achieve.
Aiming at the problems, the application provides a negative plate, an energy storage device and electric equipment, wherein the negative plate has better liquid absorption capacity and better electronic conductivity, and is favorable for considering the energy density and the dynamic performance of a battery.
The technical proposal is as follows:
an embodiment of the present application provides a negative electrode sheet including: the current collector comprises a current collector body, and a first negative electrode active layer and a second negative electrode active layer which are sequentially arranged on the surface of the current collector body.
The first negative electrode active layer and the second negative electrode active layer each independently contain a conductive agent, and in each negative electrode active layer, the conductive agent accounts for the same mass percentage of the total mass of each negative electrode active layer. That is, the mass percentage W1 of the conductive agent in the first anode active layer and the mass percentage W2 of the conductive agent in the second anode active layer in the first anode active layer satisfy: w1=w2.
The conductive agent comprises a first conductive agent and a second conductive agent; the powder conductivity ρ1 of the first conductive agent is smaller than the powder conductivity ρ2 of the second conductive agent; the oil absorption value K2 of the second conductive agent is smaller than the oil absorption value K1 of the first conductive agent. The conductivity of a powder can be used to represent the ability of the current in the powder to flow. In the present application, the powder conductivity of the conductive agent can be measured by a powder resistivity tester. The oil absorption value can be used for representing the aggregation condition of the conductive agent, and calculating the void volume and the specific surface area between the aggregates of the conductive agent, wherein the void volume and the specific surface area can be represented by the oil absorption volume of the conductive agent per unit mass. In the application, the oil absorption value can be measured by an S500 oil absorption value tester.
In the first negative electrode active layer, the percentage of the second conductive agent accounting for the total content W1 of the conductive agent of the first negative electrode active layer is recorded as X1, and the percentage of the second conductive agent accounting for the total content W2 of the conductive agent of the second negative electrode active layer in the second negative electrode active layer is recorded as X2; the negative electrode sheet satisfies: x1 > X2.
The difference between the thickness D1 of the first negative electrode active layer and the thickness D2 of the second negative electrode active layer is 0.02-0.1 mm. Optionally, the difference between D1 and D2 is within a range of 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, or any number of the above.
Through reasonable proportion of the thicknesses of the first negative electrode active layer and the second negative electrode active layer and the types of the conductive agents, the content of the second conductive agent with higher powder conductivity in the first negative electrode active layer close to the current collector is higher, the content of the first conductive agent with higher liquid absorption performance in the second negative electrode active layer correspondingly far away from the current collector is higher, the second negative electrode active layer has better electrolyte infiltration performance, the contact resistance between the first negative electrode active layer and the current collector is smaller, and the first negative electrode active layer and the second negative electrode active layer both have more proper thicknesses; the impedance of the negative electrode plate is reduced comprehensively, and the negative electrode plate can ensure better dynamic performance and better cycle stability and rate capability of the negative electrode plate under the condition of higher energy density.
In some of these embodiments, the first conductive agent comprises at least one of Super P, ketjen black, and conductive graphite. The first conductive agent has better liquid absorption capacity, and can improve electrolyte infiltration of the negative plate, thereby improving lithium ion transmission.
In some of these embodiments, the sum of the thickness D1 of the first anode active layer and the thickness D2 of the second anode active layer is 0.05 mm to 0.2 mm. The thicknesses of the first negative electrode active layer and the second negative electrode active layer are controlled to be within the range, the negative electrode plate has proper thickness, and the cycle stability and the dynamic performance of the negative electrode plate can be effectively improved under the condition of ensuring high energy density. The sum of D1 and D2 is smaller than 0.05 and mm, and the thickness of the negative electrode active layer is smaller, so that the dynamic performance of the negative electrode sheet is improved less by adjusting the composition ratio of the conductive agent in the negative electrode active layer; and when the sum of D1 and D2 is more than 0.2 and mm, the thickness of the negative electrode active layer is larger, and the dynamic performance of the negative electrode plate can be improved to a certain extent by adjusting the component proportion of the conductive agent, but the practical use requirement is difficult to achieve.
In some of these embodiments, the oil absorption value K1 of the first conductive agent satisfies: 200 The mL/100g is less than or equal to K1 and less than or equal to 600 and mL/100g. The oil absorption value K1 of the first conductive agent is in the range, the cost of the first conductive agent is low, and the first conductive agent has good liquid absorption capability and proper conductive performance. Alternatively, the first conductive agent has an oil absorption K1 in the range of 200 mL/100g, 300mL/100g, 400mL/100g, 500 mL/100g, 600mL/100g, or any number above.
In some of these embodiments, the powder conductivity ρ1 of the first conductive agent satisfies: 0.5 S/m is less than or equal to ρ1 and less than or equal to 20S/m. Optionally, the powder conductivity ρ1 of the first conductive agent is within a range of any number of compositions of 0.5S/m, 1S/m, 1.5S/m, 2S/m, 4S/m, 5S/m, 6S/m, 10S/m, 12S/m, 15S/m, 16S/m, 20S/m, or above.
In some of these embodiments, the second conductive agent includes at least one of carbon nanotubes, carbon nanofibers, and graphene. Compared with the traditional conductive agent, the second conductive agent has excellent conductivity, and can improve the conductive network among particles, thereby improving the contact resistance between the active layer and the current collector and the resistance in the active layer and reducing the impedance of the negative plate.
Optionally, the carbon nanotubes comprise at least one of single-walled carbon nanotubes and multi-walled carbon nanotubes. The average diameter of the carbon nanotubes is 2 nm-40 nm, the average length is 0.5 μm-5 μm, and the length-diameter ratio is 12.5-2500. Optionally, the length of the carbon nanofiber is 5-100 μm. Optionally, the graphene comprises at least one of single-layer graphene and multi-layer graphene. Specifically, the number of layers of graphene is 1-10. The sheet diameter of the graphene is 1-20 mu m.
In some of these embodiments, the oil absorption value K2 of the second conductive agent satisfies: 150mL/100g is less than or equal to K2 and less than or equal to 300 and mL/100g. The second conductive agent has higher length-diameter ratio or higher graphitization degree, and fewer surface defects, so that the oil absorption value is lower. Optionally, the second conductive agent has an oil absorption K2 in the range of 150mL/100g, 160 mL/100g, 180mL/100g, 200 mL/100g, 210mL/100g, 240 mL/100g, 250mL/100g, 280 mL/100g, 300mL/100g, or any combination thereof.
In some of these embodiments, the powder conductivity ρ2 of the second conductive agent satisfies: 5S/m.ltoreq.ρ2.ltoreq.400S/m. Optionally, the second conductive agent has a powder conductivity ρ2 within a range of 5S/m, 10S/m, 20S/m, 50S/m, 100S/m, 200S/m, 300S/m, 400S/m, or any number above.
It is understood that the anode sheet according to the embodiment of the present application may further include a third anode active layer, a fourth anode active layer … … nth anode active layer. The percentage of the second conductive agent in the negative electrode active layer accounting for the total content of the conductive agents is gradually decreased outwards from the surface of the current collector, and the thickness difference of any two negative electrode active layers is 0.02 mm-0.1 mm.
In some of these embodiments, the areal density CW of the negative electrode active material in the negative electrode sheet satisfies: 5.2 g/mm 2 ＜CW＜15.2 g/mm 2 . The double-layer coated negative plate is particularly suitable for thick plates, and the energy density and the dynamic performance of the battery can be well considered under the condition that the surface density of the negative electrode active material is in the range. CW < 5.2 g/mm 2 The improvement of the kinetic properties of the negative electrode sheet by the double-coated negative electrode active layer is not significant when CW > 15.2 g/mm 2 When the negative plate has larger thickness, the improvement effect of the type and content of the conductive agent on the dynamic performance is not obvious. Alternatively, the negative electrode active material has an areal density CW of 5.2 g/mm 2 、6 g/mm 2 、8 g/mm 2 、10 g/mm 2 、11.5 g/mm 2 、12 g/mm 2 、14 g/mm 2 、15.2 g/mm 2 Or any of the above.
In some of these embodiments, in the first anode active layer, the percentage Y1 of the first conductive agent to the total content W1 of the first anode active layer satisfies: y1 is more than or equal to 50 percent and less than 100 percent to 2.6 percent (CW-5.2). When Y1 is less than 50%, the second conductive agent in the first negative electrode active layer has an excessively large proportion, so that the dispersion of the slurry in the preparation process is easily influenced, and the preparation difficulty is increased. And at Y1 > 100% -2.6% (CW-5.2)%, the second conductive agent in the first anode active material layer is too low in proportion, and the conductivity of the first anode active layer decreases, resulting in an increase in the resistance of the battery. Alternatively, in the first anode active layer, the percentage Y1 of the first conductive agent to the conductive agent content is 50%, 53%, 55%, 60%, 70%, 80% or 90%.
In some of these embodiments, in the second anode active layer, the percentage Y2 of the first conductive agent to the total content W2 of the second anode active layer satisfies: 100% -2.6% (CW-5.2)% -Y2 is less than or equal to 100%. When Y2 is less than 100% -2.6% (CW-5.2)%, the first conductive agent in the second negative electrode active layer is too small, so that the liquid absorption capacity of the surface of the negative electrode sheet is reduced, the electrolyte infiltration capacity of the negative electrode sheet is poor, and the impedance of the battery is increased. Alternatively, in the second anode active layer, the percentage Y2 of the first conductive agent to the conductive agent content is 79.2%, 80%, 85%, 90%, 92%, 95% or 97%.
In some embodiments, the mass percentage of the conductive agent in each anode active layer is 0.2% -3%. The content of the conductive agent is controlled within the above range, the negative electrode sheet has good dynamic performance, and the energy density is not obviously reduced. Alternatively, the mass percentage of the conductive agent in each anode active layer is in the range of any numerical composition of 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3% or more.
In some embodiments, the mass percentage of the anode active material in each anode active layer is 90% -99.5%. The mass percentage of the anode active material is within the above range, and the anode sheet has a higher energy density. Alternatively, the mass percentage of the anode active material in each anode active layer is in the range of any numerical composition of 90%, 92%, 94%, 95%, 96%, 98%, 99%, 99.5% or more.
In some of these embodiments, the negative active material of the negative electrode sheet includes at least one of graphite, soft carbon, hard carbon, a silicon-based material, and lithium titanate.
In addition, an embodiment of the present application further provides a method for preparing the negative electrode sheet, including the following steps:
s1: and respectively preparing a first slurry and a second slurry according to the design of the negative electrode plate.
S2: and coating a first slurry and a second slurry on the surface of the current collector to prepare a first anode active layer and a second anode active layer.
In some embodiments, the first slurry and the second slurry may be sequentially coated in step S2, or the first slurry and the second slurry may be simultaneously coated by a dual-layer coater.
In some embodiments, in step S2, the coated first slurry and second slurry are dried and cold-pressed to form a first negative electrode active layer and a second negative electrode active layer on the surface of the current collector.
The application further provides an energy storage device, which comprises the negative plate. Therefore, the energy storage device has all the features and advantages of the negative electrode sheet, and the details are not repeated here. Overall, the energy storage device has a higher energy density and better kinetic performance.
The energy storage device may be a lithium ion battery, and the positive electrode material of the lithium ion battery may be any positive electrode material, for example, lithium iron phosphate, lithium cobalt oxide, ternary material, and the like, which is not limited in the embodiment of the present application.
The application further provides electric equipment, which comprises the energy storage device, wherein the energy storage device supplies power for the electric equipment. For example, the powered device may include a plurality of battery packs formed from the lithium-ion batteries described above. The electric device can be a lighting lamp, etc., so that it can be known that the electric device has all the features and advantages of the negative plate described above, and the details are not repeated here.
The present application will be illustrated by the following examples, which are given for illustrative purposes only and are not intended to limit the scope of the present application in any way, and unless otherwise specified, the conditions or procedures not specifically described are conventional and the reagents and materials employed are commercially available.
The raw material description: the Super P used in the following examples and comparative examples had an oil absorption of 290. 290 mL/100g and a powder conductivity of 1.2S/m. The Ketjen black had an oil absorption of 400mL/100g and a powder conductivity of 6S/m. The oil absorption value of the carbon nano tube is 170mL/100g, and the powder conductivity is 50S/m. The oil absorption value of the graphene is 300mL/100g, and the powder conductivity is 350S/m. The oil absorption value is measured by an S500 oil absorption value tester, the powder conductivity is tested by a powder resistance tester, and the equipment model is the primary energy science and technology PRCD3100. Placing the dried powder sample in a die/sample chamber of a resistivity tester, sample chamber depth 20 mm, cross-sectional area 1 cm 2 Then testing the corresponding powder resistivity test result under 5 MPa.
Example 1
(1) Preparing a negative plate:
artificial graphite as a cathode active material, a conductive agent, a thickener carboxymethyl cellulose CMC and a binder polyacrylic acid PAA according to the solid content ratio of 96 percent: 1%:1%: mixing and dispersing the mixture with solvent water for 80min to obtain first slurry. Wherein the conductive agent comprises the following components in percentage by mass: 30% SuperP and carbon nanotubes.
The negative electrode active material artificial graphite, a conductive agent, a thickener carboxymethyl cellulose CMC and a binder polyacrylic acid PAA are mixed according to the solid content ratio of 96 percent: 1%:1%: mixing and dispersing 2% of the mixture with solvent water for 77min to obtain second slurry. Wherein the conductive agent comprises 92% by mass: 8% SuperP and carbon nanotubes.
Adopting a double-die coating head extrusion coater, wherein a feeding channel communicated with two discharge holes is arranged in the coating head, and the first sizing agent and the second sizing agent are simultaneously extruded under the control of a screw pump according to the design thickness of the negative electrode active layer in the table 1The two slurries are coated on the negative electrode current collector with the conductive coating at the same time, and the surface density of the single-sided negative electrode active material of the negative electrode plate is controlled to be 11.5 g/mm 2 The prepared double-layer coating pole piece with the second negative electrode active layer on the top layer and the first negative electrode active layer on the bottom layer. After one side of the current collector is coated, the other side is repeatedly coated in the manner described above.
(2) Preparation of a positive plate: lithium iron phosphate (LiFePO) as a positive electrode active material 4 ) Fully stirring and mixing the conductive agent acetylene black and the binder polyvinylidene fluoride (PVDF) in a mass ratio of 96:2:2 in a proper amount of N-methylpyrrolidone (NMP) solvent to form uniform anode slurry; and coating the positive electrode slurry on an Al foil of a positive electrode current collector, and drying and cold pressing to obtain the positive electrode plate.
(3) Preparation of a lithium ion battery: PE porous polymer film is used as a isolating film. Ethylene Carbonate (EC) and diethyl carbonate (DEC) are mixed according to a volume ratio of 3:7, followed by mixing, and then drying the lithium salt LiPF sufficiently 6 Dissolving in a mixed organic solvent according to a proportion of 1mol/L to obtain a basic electrolyte, and finally adding 2wt% of fluoroethylene carbonate (FEC) to prepare the electrolyte. Sequentially stacking the positive electrode, the isolating film and the negative electrode, enabling the isolating film to be positioned between the positive electrode and the negative electrode to play a role of isolation, and then winding to obtain a bare cell; and placing the bare cell in an outer packaging foil, injecting the prepared electrolyte into the dried cell, and performing the procedures of vacuum packaging, standing, formation, shaping and the like to prepare the lithium ion cell.
Example 2
Unlike example 1, in this example, the conductive agent of the first paste includes 53% by mass: 47% SuperP and carbon nanotubes; the dispersion time of the first slurry was 130min. The conductive agent in the second slurry comprises 85% by mass: 15% SuperP and carbon nanotubes; the dispersion time of the second slurry was 75min.
Example 3
Unlike example 1, in this example, the conductive agent of the first paste includes 83% by mass: 17% SuperP and carbon nanotubes; the dispersion time of the first slurry was 77min. The conductive agent in the second slurry comprises 97% by mass: 3% SuperP and carbon nanotubes; the dispersion time of the second slurry was 75min.
Example 4
Unlike example 1, in this example, the conductive agent of the first paste includes 40% by mass: 60% SuperP and carbon nanotubes; the dispersion time of the first slurry was 150min. The conductive agent in the second slurry comprises 80% by mass: 20% SuperP and carbon nanotubes; the dispersion time of the second slurry was 80min.
Example 5
Unlike example 1, in this example, the conductive agent of the first paste includes a mass ratio of 90%:10% SuperP and carbon nanotubes; the dispersion time of the first slurry was 75min. The conductive agent in the second slurry is SuperP; the dispersion time of the second slurry was 75min.
Example 6
Unlike example 1, in this example, the conductive agent of the first paste includes a mass ratio of 70%:30% of ketjen black and graphene; the dispersion time of the first slurry was 120min. The conductive agent in the second slurry comprises 92% by mass: 8% of Keqin black and graphene; the dispersion time of the second slurry was 112min.
Comparative example 1
Unlike example 1, in this comparative example, the negative electrode sheet was produced by: artificial graphite as a cathode active material, a conductive agent, a thickener carboxymethyl cellulose CMC and a binder polyacrylic acid PAA according to the solid content ratio of 96 percent: 1%:1%: mixing and dispersing 2% of the solution and solvent water for 75min to obtain the cathode slurry. And coating the negative electrode slurry on a negative electrode current collector with a conductive coating, and drying and cold pressing to obtain a negative electrode plate. The surface density of the single-surface negative electrode active material of the prepared negative electrode plate is 11.5 g/mm 2 。
Comparative example 2
The difference from example 1 is that in this comparative example, the thicknesses of the first anode active layer and the second anode active layer are different. The thickness W1 of the first anode active layer was 0.125 and mm. The thickness W2 of the second anode active layer was 0.016 and mm.
Comparative example 3
The difference from example 1 is that in this comparative example, the thicknesses of the first anode active layer and the second anode active layer are different. The thickness W1 of the first anode active layer was 0.071 mm. The thickness W2 of the second anode active layer was 0.07 mm.
And (3) testing:
(1) Thickness test of the first anode active layer, second anode active layer: firstly, carrying out argon ion polishing Cutting (CP) on a negative plate sample along the direction perpendicular to a current collector to obtain the cross section of the negative plate, and then observing the cross section morphology of the negative plate through a scanning electron microscope and measuring.
(2) Negative sheet areal Density CW test: taking completely discharged lithium ion batteries, disassembling each lithium ion battery to obtain a negative plate, cleaning, drying, and using a diameter of 1540.25mm 2 Blanking 5 complete pole pieces in a flat single-sided area of the negative pole piece, weighing, and calculating the unit area density CW1 of the pole pieces according to the quality of the pole pieces and the area of the punched pole pieces; taking completely discharged lithium ion batteries, disassembling each negative electrode plate, soaking the negative electrode plates by pure water to remove negative electrode active substances, soaking the negative electrode plates by pure water for three times to clean the negative electrode plates until a large number of continuous areas in the electrode plates are not covered by active materials, drying the negative electrode plates, and using the diameter of 1540.25mm 2 Blanking 5 complete foil materials in a flat single-sided area of the cathode, weighing, and calculating the unit area density CW2 of the foil materials according to the foil material quality and the punched area; negative plate cw= (CW 1-CW 2)/2.
(3) And (3) testing lithium ion battery lithium precipitation power: ten lithium ion batteries prepared in each comparative example and example are taken, the batteries are firstly placed at 25 ℃ for being placed for 1 hour, then two batteries are taken as one group, and constant power charging of 0.6P,0.8P,1P,1.2P,1.4P,1.6P,1.8P,2P and 2.2P to 3.65V is respectively carried out according to the groups; standing for 30min, discharging to 2.5V with constant power of 0.6P,0.8P,1P,1.2P,1.4P,1.6P,1.8P,2P,2.2P, standing for 30min, charging to 3.65V with constant power of 0.6P,0.8P,1P,1.2P,1.4P,1.6P,1.8P,2P,2.2P, respectively, and disassembling the battery to observe lithium precipitation condition of the surface of the cathode. The power at which lithium evolution occurs at the negative electrode was recorded.
And (3) judging the lithium precipitation degree: the negative electrode is judged according to the state of fully charged and disassembled, and when the whole negative electrode is displayed as golden yellow and the area of the negative electrode displayed as silver gray is less than 2 percent, the negative electrode is judged to be free from lithium precipitation; and when the whole negative electrode is golden yellow and the area of silver gray is more than or equal to 2%, judging that lithium is separated.
(4) And (3) testing the cycle performance: the lithium ion batteries prepared in each of the comparative examples and examples were each taken 5 times and averaged. The lithium ion battery was repeatedly charged and discharged by the following steps, and the discharge capacity retention rate of the lithium ion battery was calculated.
Firstly, carrying out first charge and discharge in an environment of 25 ℃, carrying out constant power charge under the charge power of 1P until reaching an upper limit voltage of 3.65V, converting into constant voltage charge, then carrying out constant power discharge under the discharge power of 1P until reaching a final voltage of 2.5V, repeating twice, and recording the discharge capacity of a second cycle; then, 5000 charge and discharge cycles were performed, and the discharge capacity at the 5000 th cycle was recorded.
Cycle 5000 cycles capacity retention= (discharge capacity of 5000 th cycle/discharge capacity of second cycle) ×100%.
The compositions and test data of the lithium ion batteries of examples 1 to 6 and comparative examples 1 to 3 are recorded in table 1.
TABLE 1
As can be seen from the data related to table 1, in examples 1 to 6, by adjusting the composition ratio of the conductive agent of the double-layer coated negative electrode sheet, the lithium ion battery has a higher cycle capacity retention rate and can be charged and discharged at a higher power without generating lithium precipitation, compared with the single-layer coated negative electrode sheet of comparative example 1. The lithium ion batteries of examples 1-6 have better cycling stability and rate capability and better cycling performance and dynamic performance under the same surface density. In example 4, y2=80%, not satisfying 100% -2.6% (CW-5.2)% -Y2 is not more than 100%, in example 5, y1=90%, not satisfying 50% < Y1 < 100% -2.6% (CW-5.2)%, lithium ion batteries of examples 4-5 are charged and discharged under 0.8 p-1 p constant power to generate lithium precipitation, and the cycle capacity retention rate is 80.9% -85.3%, compared with examples 4-5, the cycle performance and the rate performance of lithium ion batteries of examples 1-3 are better. Compared with comparative examples 2-3, the negative electrode sheet of example 1 has better cycle stability and rate capability of the lithium ion battery by reasonably controlling the thicknesses of the first negative electrode active layer and the second negative electrode active layer.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples merely represent a few embodiments of the present application, which facilitate a specific and detailed understanding of the technical solutions of the present application, but are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. It should be understood that, based on the technical solutions provided by the present application, those skilled in the art obtain technical solutions through logical analysis, reasoning or limited experiments, all of which are within the scope of protection of the appended claims. The scope of the patent of the application should therefore be determined with reference to the appended claims, which are to be construed as in accordance with the doctrines of claim interpretation.
Claims (10)
1. A negative electrode sheet, comprising: a current collector, a first negative electrode active layer and a second negative electrode active layer which are sequentially arranged on the surface of the current collector;
the first negative electrode active layer and the second negative electrode active layer each independently contain a conductive agent, and in each negative electrode active layer, the conductive agent accounts for the same mass percentage of the total mass of each negative electrode active layer; wherein the conductive agent comprises a first conductive agent and a second conductive agent; the powder conductivity ρ1 of the first conductive agent is smaller than the powder conductivity ρ2 of the second conductive agent; the oil absorption value K2 of the second conductive agent is smaller than the oil absorption value K1 of the first conductive agent;
in the first negative electrode active layer, the percentage of the second conductive agent accounting for the total content W1 of the first negative electrode active layer is denoted as X1, and the percentage of the second conductive agent accounting for the total content W2 of the second negative electrode active layer is denoted as X2; the negative electrode sheet satisfies: x1 > X2;
the oil absorption value K1 of the first conductive agent satisfies the following conditions: 200. 200 mL/100g K1/600 mL/100g;
the oil absorption value K2 of the second conductive agent satisfies the following conditions: 150mL/100g K2 is less than or equal to 300mL/100 g;
the powder conductivity ρ1 of the first conductive agent satisfies: 0.5 S/m is less than or equal to ρ1 and less than or equal to 20S/m;
the powder conductivity ρ2 of the second conductive agent satisfies: 5S/m is more than or equal to ρ2 and less than or equal to 400S/m;
the difference of the thickness D1 of the first negative electrode active layer and the thickness D2 of the second negative electrode active layer is 0.02 mm-0.1 mm;
the sum of the thickness D1 of the first negative electrode active layer and the thickness D2 of the second negative electrode active layer is 0.05-0.2 mm;
the surface density CW of the negative electrode active material in the negative electrode sheet satisfies: 5.2 g/mm 2 ＜CW＜15.2 g/mm 2 ；
In the first anode active layer, the percentage Y1 of the first conductive agent in the total content W1 of the first anode active layer satisfies: y1 is more than or equal to 50 percent and less than 100 percent to 2.6 percent (CW-5.2);
in the second anode active layer, the percentage Y2 of the first conductive agent to the total content W2 of the second anode active layer satisfies: 100% -2.6% (CW-5.2)% -Y2 is less than or equal to 100%.
2. The negative electrode sheet according to claim 1, wherein the negative electrode sheet satisfies at least one condition of (1) to (2):
(1) The first conductive agent comprises at least one of Super P, ketjen black and conductive graphite;
(2) The second conductive agent comprises at least one of carbon nanotubes, carbon nanofibers and graphene.
3. The negative electrode sheet according to claim 2, wherein the carbon nanotubes have an average diameter of 2 nm to 40 nm, an average length of 0.5 μm to 5 μm, and an aspect ratio of 12.5 to 2500.
4. The negative electrode sheet according to claim 2, wherein the number of layers of graphene is 1 to 10, and the sheet diameter of graphene is 1 μm to 20 μm.
5. The negative electrode sheet according to claim 1, wherein the surface density CW of the negative electrode active material in the negative electrode sheet satisfies: 5.2 g/mm 2 、6 g/mm 2 、8 g/mm 2 、10 g/mm 2 、11.5 g/mm 2 、12 g/mm 2 、14 g/mm 2 Or 15.2 g/mm 2 。
6. The negative electrode sheet of claim 1, wherein the difference between the thickness D1 of the first negative electrode active layer and the thickness D2 of the second negative electrode active layer is 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, or 0.1 mm.
7. The negative electrode sheet according to any one of claims 1 to 6, wherein the negative electrode sheet satisfies at least one condition of (1) to (2):
(1) In each negative electrode active layer, the mass percentage of the conductive agent is 0.2% -3%;
(2) In each negative electrode active layer, the mass percentage of the negative electrode active material is 90% -99.5%.
8. The negative electrode sheet according to any one of claims 1 to 6, wherein a negative electrode active material of the negative electrode sheet includes at least one of graphite, soft carbon, hard carbon, a silicon-based material, and lithium titanate.
9. An energy storage device comprising the negative electrode sheet according to any one of claims 1 to 8.
10. A powered device comprising the energy storage device of claim 9, the energy storage device providing power to the powered device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310834599.8A CN116565211B (en) | 2023-07-10 | 2023-07-10 | Negative plate, energy storage device and electric equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310834599.8A CN116565211B (en) | 2023-07-10 | 2023-07-10 | Negative plate, energy storage device and electric equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116565211A CN116565211A (en) | 2023-08-08 |
| CN116565211B true CN116565211B (en) | 2023-09-26 |
Family
ID=87486548
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310834599.8A Active CN116565211B (en) | 2023-07-10 | 2023-07-10 | Negative plate, energy storage device and electric equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116565211B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2019057446A (en) * | 2017-09-21 | 2019-04-11 | 日立化成株式会社 | Lithium ion battery and manufacturing method of the same |
| CN112018328A (en) * | 2020-09-21 | 2020-12-01 | 珠海冠宇电池股份有限公司 | Silicon-doped negative plate and lithium ion battery comprising same |
| WO2022057668A1 (en) * | 2020-09-21 | 2022-03-24 | 珠海冠宇电池股份有限公司 | Negative electrode plate, preparation method therefor, and battery |
| CN115528205A (en) * | 2022-09-21 | 2022-12-27 | 合肥国轩高科动力能源有限公司 | Double-step type pole piece and lithium ion battery |
| CN116053412A (en) * | 2023-01-28 | 2023-05-02 | 浙江衡远新能源科技有限公司 | Lithium ion battery negative plate |
| CN116111046A (en) * | 2023-04-11 | 2023-05-12 | 宁德新能源科技有限公司 | Negative electrode sheet, secondary battery, and electronic device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| PL3678228T3 (en) * | 2017-12-01 | 2023-01-16 | Lg Energy Solution, Ltd. | Negative electrode and secondary battery including the same |
-
2023
- 2023-07-10 CN CN202310834599.8A patent/CN116565211B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2019057446A (en) * | 2017-09-21 | 2019-04-11 | 日立化成株式会社 | Lithium ion battery and manufacturing method of the same |
| CN112018328A (en) * | 2020-09-21 | 2020-12-01 | 珠海冠宇电池股份有限公司 | Silicon-doped negative plate and lithium ion battery comprising same |
| WO2022057668A1 (en) * | 2020-09-21 | 2022-03-24 | 珠海冠宇电池股份有限公司 | Negative electrode plate, preparation method therefor, and battery |
| CN115528205A (en) * | 2022-09-21 | 2022-12-27 | 合肥国轩高科动力能源有限公司 | Double-step type pole piece and lithium ion battery |
| CN116053412A (en) * | 2023-01-28 | 2023-05-02 | 浙江衡远新能源科技有限公司 | Lithium ion battery negative plate |
| CN116111046A (en) * | 2023-04-11 | 2023-05-12 | 宁德新能源科技有限公司 | Negative electrode sheet, secondary battery, and electronic device |
Non-Patent Citations (1)
| Title |
|---|
| 石墨负极锂离子电池中两种导电剂的研究;沈一丁;王娜;杨晓武;杨蕊;李晓叶;刘超;;陕西科技大学学报(06);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116565211A (en) | 2023-08-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111525099B (en) | Sodium ion battery | |
| US8802289B2 (en) | Composition for electrode comprising an iron compound with carbon and a (meth)acrylate-nitrile copolymer | |
| CN111640940A (en) | Negative plate and secondary battery | |
| JP2018523281A (en) | Positive electrode mixture and secondary battery including the same | |
| WO2021109080A1 (en) | Lithium ion battery, positive electrode sheet for lithium ion battery, and device | |
| CN111799470B (en) | Positive pole piece and sodium ion battery | |
| CN114759157B (en) | Negative electrode piece, preparation method thereof and lithium secondary battery | |
| EP3598544A1 (en) | Conductive material dispersion liquid for electrochemical element electrodes, slurry composition for electrochemical element electrodes, method for producing same, electrode for electrochemical elements, and electrochemical element | |
| CN112103509B (en) | Positive electrode current collector, positive electrode plate, lithium ion battery and battery module | |
| CN114665065A (en) | Positive pole piece and preparation method and application thereof | |
| CN111653732A (en) | Positive electrode material, positive electrode plate and lithium ion battery | |
| CN112349900A (en) | Negative pole piece and lithium ion battery containing same | |
| CN112151755A (en) | Positive plate and battery | |
| JP3615472B2 (en) | Non-aqueous electrolyte battery | |
| CN106602069A (en) | Lithium ion battery positive electrode material, positive electrode and lithium ion battery | |
| CN114373927A (en) | Negative electrode material and negative electrode plate comprising same | |
| CN111540886B (en) | Negative electrode material, preparation method thereof and multilayer electrode | |
| CN113130907A (en) | Battery cell, preparation method thereof and fast-charging lithium ion battery | |
| CN117457903A (en) | Negative electrode active material, negative electrode sheet, and use thereof | |
| CN117038856A (en) | Negative pole piece, battery pack and electric equipment | |
| CN113921756A (en) | Silicon-carbon negative electrode piece with high silicon content and preparation method thereof | |
| CN116565211B (en) | Negative plate, energy storage device and electric equipment | |
| JP2013161689A (en) | Secondary battery electrode and manufacturing method of the same | |
| JP2013084399A (en) | Lithium ion secondary battery anode manufacturing method and lithium ion secondary battery manufacturing method | |
| CN115602787A (en) | Negative pole piece and lithium ion 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 |