CN112271283A - Negative pole piece and lithium ion battery - Google Patents
Negative pole piece and lithium ion battery Download PDFInfo
- Publication number
- CN112271283A CN112271283A CN202011157917.4A CN202011157917A CN112271283A CN 112271283 A CN112271283 A CN 112271283A CN 202011157917 A CN202011157917 A CN 202011157917A CN 112271283 A CN112271283 A CN 112271283A
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- dressing layer
- pole piece
- layer
- negative electrode
- dressing
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/665—Composites
- H01M4/667—Composites in the form of layers, e.g. coatings
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- 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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/386—Silicon or alloys based on silicon
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention discloses a negative pole piece and a lithium ion battery, wherein the negative pole piece comprises a current collector, a first dressing layer positioned on the surface of the current collector and a second dressing layer covering the surface of the first dressing layer, the active substance of the first dressing layer is silicon or a silicon-carbon composite material, and the active substance of the second dressing layer is one or more of artificial graphite, natural graphite, soft carbon and hard carbon. The cathode pole piece can improve the cycle life of a silicon cathode or a silicon-containing material cathode battery, and the capacity retention rate of a battery cell after 200 cycles reaches over 88 percent.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a negative pole piece and a lithium ion battery.
Background
In recent years, lithium ion batteries are widely used in new energy vehicles. With the increasing requirement of new energy automobiles on the energy density of the battery cell, the current commercialized lithium ion negative electrode material adopts a graphite carbon-based material, and the theoretical specific capacity value of the material is only 372mAh g-1And the requirement of the electric automobile on the high-specific-capacity battery can not be met. Among many non-carbon based negative electrode materials, silicon has a theoretical specific capacity (4200mAh g)-1) Have received great attention from the industry. However, in the actual charging and discharging process, the volume change of the silicon material reaches more than 300%, and the mechanical force generated by the violent volume change can cause the serious pulverization of the silicon and the falling off from the current collector, so that the specific capacity is sharply reduced, and finally the service life of the battery is reduced. At present, from the viewpoint of improving raw materials, the industry adopts methods of nanocrystallization, porosification, silicon-carbon composite, and introduction of an expansion medium on the surface of a silicon material to improve the cycle life of the silicon material, but few researchers or researchers have studied from the viewpoint of pole piece design. Therefore, it is very necessary to design a negative electrode plate of silicon material to improve the cycle life of the silicon material negative electrode.
Disclosure of Invention
The invention aims to provide a negative pole piece and a lithium ion battery, wherein the pole piece can improve the cycle life of a silicon negative pole or a silicon-containing material negative pole battery.
In order to achieve the purpose, the invention provides the following technical scheme:
a negative pole piece comprises a current collector, a first dressing layer located on the surface of the current collector and a second dressing layer covering the surface of the first dressing layer, wherein an active substance of the first dressing layer is silicon or a silicon-carbon composite material, and an active substance of the second dressing layer is one or more of artificial graphite, natural graphite, soft carbon and hard carbon.
The further technical proposal is that the mass of the active substance in the first dressing layer accounts for 5-15 wt% of the mass of the active substance in the second dressing layer, and the sum of the mass of the active substance in the first dressing layer and the mass of the active substance in the second dressing layer is 90-98 wt% of the total weight of all the dressings.
The further technical scheme is that the ratio of the width of the first dressing layer to the width of the second dressing layer is 1:10-5: 10.
The further technical proposal is that the thickness of the first dressing layer is 40-80 μm, and the thickness of the second dressing layer is 100-240 μm.
The further technical scheme is that the current collector is copper foil or foam copper, and the thickness of the current collector is 4.5-20 um.
The further technical scheme is that the width of the current collector is larger than that of the second dressing layer, and tabs are arranged on the two sides of the second dressing layer of the current collector.
The further technical scheme is that the conductive agent in the first dressing layer and the second dressing layer is selected from one or more of ultrafine conductive carbon black, carbon nano tubes, graphene, ketjen black and carbon black, and the mass fraction of the conductive agent in the dressing layers is 1-3 wt%.
The further technical scheme is that the binder in the first dressing layer and the second dressing layer is selected from one or more of sodium carboxymethylcellulose, styrene butadiene rubber, polyvinylidene fluoride and polyacrylic acid.
The further technical scheme is that the mass fraction of the binder in the first dressing layer is 3-7 wt%, and the mass fraction of the binder in the second dressing layer is 2-5 wt%.
The preparation method of the negative pole piece comprises the following steps:
(1) preparing slurry required by the dressing layer A, coating the surface of the current collector in a double-sided coating mode, baking and rolling after coating is finished, and obtaining a pole piece containing the dressing layer A;
(2) preparing slurry required by the dressing of the layer B, coating the slurry of the layer B on the pole piece containing the dressing layer A in a double-sided coating mode, baking and rolling after coating, and obtaining the negative pole piece.
The invention also provides a lithium ion battery, which comprises a positive pole piece, a diaphragm, electrolyte and a negative pole piece, wherein the negative pole piece is the negative pole piece.
Compared with the prior art, the invention has the following beneficial effects: according to the invention, the artificial graphite, the natural graphite, the soft carbon, the hard carbon and other traditional commercial negative active material dressing layers are coated on the silicon or silicon-carbon dressing layer, and the volume change of the silicon material is inhibited through the weight and coating of the artificial graphite, the natural graphite, the soft carbon, the hard carbon and other dressing layers, so that the silicon material is prevented from falling off from a current collector after being pulverized and the cycle performance of the battery cell is further prevented from being influenced.
Drawings
FIG. 1 is a schematic cross-sectional view of a negative electrode plate according to the present invention;
the electrode comprises a first coating layer, a second coating layer, a current collector, a pole lug, a first electrode, a second electrode, a third electrode and a fourth electrode, wherein A is the first coating layer, B is the second coating layer, C is the current collector, D is the pole lug, E is the width of the first coating layer, F is the width of the second coating layer, G is the thickness of the first coating layer, and H is the thickness of the second coating layer.
Detailed Description
The invention will be further explained and explained with reference to the drawings and the embodiments.
Example 1
As shown in figure 1, the invention provides a negative pole piece, which comprises a current collector C, a first dressing layer A positioned on the surface of the current collector and a second dressing layer B covering the surface of the first dressing layer, wherein the active material of the first dressing layer is silicon or silicon-carbon composite material, the active material of the second dressing layer is one or more of artificial graphite, natural graphite, soft carbon and hard carbon, the mass of the active material in the first dressing layer accounts for 5-15 wt% of the mass of the active material in the second dressing layer, and the sum of the mass of the active material in the first dressing layer and the mass of the active material in the second dressing layer accounts for 90-98 wt% of the total weight of all dressings. The ratio of the width E of the first dressing layer to the width F of the second dressing layer is 1:10-5: 10. The thickness G of the first dressing layer is 40-80 μm, and the thickness H of the second dressing layer is 100-240 μm. The mass flow body is copper foil or copper foam, and thickness is 4.5um-20 um. The width of the current collector is larger than that of the second dressing layer, and tabs D are arranged on the two sides of the second dressing layer of the current collector. The conductive agent in the first dressing layer and the second dressing layer is selected from one or more of SP, CNT, graphene, Ketjen black and carbon black, and the mass fraction of the conductive agent in the dressing layers is 1-3 wt%. The binder in the first and second dressing layers is selected from one or more of CMC, SBR, PVDF, PAA. The mass fraction of the binder in the first dressing layer is 3-7 wt%, and the mass fraction of the binder in the second dressing layer is 2-5 wt%.
Example 2
The preparation method of the negative pole piece specifically comprises the following steps:
(1) preparing 1kg of silicon negative electrode slurry: silicon material: mixing a conductive agent, a binder and a thickening agent according to a mass ratio of 90:5:2:1, and then adding water and stirring to prepare silicon negative electrode slurry;
(2) preparing 10kg of graphite cathode slurry: artificial graphite: mixing the conductive agent, the binder and the thickening agent in a mass ratio of 90:5:2:1, and then adding water and stirring to prepare graphite cathode slurry;
(3) coating 1kg of silicon negative electrode slurry, baking and rolling to obtain a pole piece with the thickness of the silicon-containing dressing being 60um, wherein the coating width is 20 mm;
(4) coating 10kg of graphite negative electrode slurry on a silicon material-containing pole piece, wherein the coating width is 80mm, and baking and rolling are carried out after the coating is finished to obtain a negative pole piece with the thickness of 140 mu m;
example 3
The difference from example 1 is only that the mass of the graphite negative electrode slurry was 20kg, and the remaining steps and parameters were the same.
Example 4
The difference from example 1 is only that the mass of the graphite negative electrode slurry was 6.7kg, and the remaining steps and parameters were the same.
Example 5
The difference from example 1 is only that the coating width of silicon negative electrode slurry is 40mm, and the rest steps and parameters are the same.
Example 6
The difference from example 1 is only that the coating width of the silicon anode slurry is 30mm, and the rest of the steps and parameters are the same.
Example 7
The difference from example 1 is only that the thickness of the silicon negative electrode dressing after rolling is 40um, and the rest steps and parameters are the same.
Example 8
The difference from example 1 is only that the thickness of the silicon negative electrode dressing after rolling is 80um, and the rest steps and parameters are the same.
Comparative example 1
The difference from example 1 is that: and pressing the silicon negative electrode slurry coating roller into a negative electrode plate with the width of 20mm and the thickness of 60um, wherein a second dressing layer is not arranged.
The negative pole pieces prepared in examples 2 to 8 and comparative example 1 and the lithium iron phosphate positive pole piece were assembled into a soft-packaged cell of 1Ah specification, and after liquid injection and formation, the cell was subjected to a normal temperature cycle test. The normal temperature cycle performance of the cell is shown in table 1:
table 1 test results of normal temperature cycle performance of electric core
As can be seen from table 1, the examples of the present application have a significant improvement in cycle life of the negative electrode or the negative electrode battery containing silicon material, as compared to comparative example 1 without the second coating layer.
Although the present invention has been described herein with reference to the illustrated embodiments thereof, which are intended to be preferred embodiments of the present invention, it is to be understood that the invention is not limited thereto, and that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure.
Claims (10)
1. The negative pole piece is characterized by comprising a current collector, a first dressing layer positioned on the surface of the current collector and a second dressing layer covering the surface of the first dressing layer, wherein an active substance of the first dressing layer is silicon or a silicon-carbon composite material, and an active substance of the second dressing layer is one or more of artificial graphite, natural graphite, soft carbon and hard carbon.
2. The negative electrode plate of claim 1, wherein the mass of the active material in the first dressing layer accounts for 5-15 wt% of the mass of the active material in the second dressing layer, and the sum of the mass of the active material in the first dressing layer and the mass of the active material in the second dressing layer is 90-98 wt% of the total weight of all the dressings.
3. The negative electrode tab of claim 1, wherein the ratio of the width of the first coating layer to the width of the second coating layer is 1:10 to 5: 10.
4. The negative electrode plate as claimed in claim 1, wherein the thickness of the first coating layer is 40-80 μm, and the thickness of the second coating layer is 100-240 μm.
5. The negative pole piece of claim 1, wherein the current collector is a copper foil or a copper foam with a thickness of 4.5um-20 um.
6. The negative electrode tab of claim 1, wherein the current collector has a width greater than the width of the second coating layer, the current collector being provided with tabs on both sides of the second coating layer.
7. The negative electrode plate as claimed in claim 1, wherein the conductive agent in the first and second coating layers is selected from one or more of ultra-fine conductive carbon black, carbon nanotube, graphene, ketjen black and carbon black, and the mass fraction of the conductive agent in the coating layers is 1-3 wt%.
8. The negative electrode plate as claimed in claim 1, wherein the binder in the first and second coating layers is selected from one or more of sodium carboxymethylcellulose, styrene butadiene rubber, polyvinylidene fluoride and polyacrylic acid.
9. The negative electrode sheet according to claim 1, wherein the mass fraction of the binder in the first coating layer is 3 to 7 wt%, and the mass fraction of the binder in the second coating layer is 2 to 5 wt%.
10. A lithium ion battery is characterized by comprising a positive pole piece, a diaphragm, electrolyte and a negative pole piece, wherein the negative pole piece is the negative pole piece of any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011157917.4A CN112271283A (en) | 2020-10-26 | 2020-10-26 | Negative pole piece and lithium ion battery |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011157917.4A CN112271283A (en) | 2020-10-26 | 2020-10-26 | Negative pole piece and lithium ion battery |
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| Publication Number | Publication Date |
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| CN112271283A true CN112271283A (en) | 2021-01-26 |
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| CN202011157917.4A Pending CN112271283A (en) | 2020-10-26 | 2020-10-26 | Negative pole piece and lithium ion battery |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113078291A (en) * | 2021-03-26 | 2021-07-06 | 珠海冠宇电池股份有限公司 | Negative plate, preparation method thereof and battery |
| CN114284466A (en) * | 2021-12-27 | 2022-04-05 | 珠海冠宇电池股份有限公司 | Negative plate, battery and electronic equipment |
| CN115000407A (en) * | 2022-06-13 | 2022-09-02 | 万向一二三股份公司 | Silicon-based negative electrode plate and preparation method and application thereof |
| CN115347241A (en) * | 2022-10-14 | 2022-11-15 | 宁德新能源科技有限公司 | Electrochemical device and electronic device |
| WO2023246795A1 (en) * | 2022-06-21 | 2023-12-28 | 比亚迪股份有限公司 | Negative electrode sheet, secondary battery, and electric device |
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| CN107528044A (en) * | 2017-07-25 | 2017-12-29 | 深圳市沃特玛电池有限公司 | A kind of lithium ion battery negative electrode and preparation method thereof |
| CN109216654A (en) * | 2018-10-18 | 2019-01-15 | 天津中聚新能源科技有限公司 | A kind of lithium ion battery of multilayer cathode pole piece and its preparation method and application |
| CN109888266A (en) * | 2019-02-28 | 2019-06-14 | 东莞塔菲尔新能源科技有限公司 | A kind of silicon-based anode piece and preparation method thereof and lithium ion battery |
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2020
- 2020-10-26 CN CN202011157917.4A patent/CN112271283A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107528044A (en) * | 2017-07-25 | 2017-12-29 | 深圳市沃特玛电池有限公司 | A kind of lithium ion battery negative electrode and preparation method thereof |
| CN109216654A (en) * | 2018-10-18 | 2019-01-15 | 天津中聚新能源科技有限公司 | A kind of lithium ion battery of multilayer cathode pole piece and its preparation method and application |
| CN109888266A (en) * | 2019-02-28 | 2019-06-14 | 东莞塔菲尔新能源科技有限公司 | A kind of silicon-based anode piece and preparation method thereof and lithium ion battery |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113078291A (en) * | 2021-03-26 | 2021-07-06 | 珠海冠宇电池股份有限公司 | Negative plate, preparation method thereof and battery |
| CN114284466A (en) * | 2021-12-27 | 2022-04-05 | 珠海冠宇电池股份有限公司 | Negative plate, battery and electronic equipment |
| CN115000407A (en) * | 2022-06-13 | 2022-09-02 | 万向一二三股份公司 | Silicon-based negative electrode plate and preparation method and application thereof |
| WO2023246795A1 (en) * | 2022-06-21 | 2023-12-28 | 比亚迪股份有限公司 | Negative electrode sheet, secondary battery, and electric device |
| CN115347241A (en) * | 2022-10-14 | 2022-11-15 | 宁德新能源科技有限公司 | Electrochemical device and electronic device |
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Application publication date: 20210126 |