CN116504916A - Negative electrode for power battery and preparation method thereof - Google Patents
Negative electrode for power battery and preparation method thereof Download PDFInfo
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- CN116504916A CN116504916A CN202310413355.2A CN202310413355A CN116504916A CN 116504916 A CN116504916 A CN 116504916A CN 202310413355 A CN202310413355 A CN 202310413355A CN 116504916 A CN116504916 A CN 116504916A
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- 238000010288 cold spraying Methods 0.000 claims abstract description 45
- 238000000034 method Methods 0.000 claims abstract description 33
- 229920000642 polymer Polymers 0.000 claims abstract description 29
- 230000008569 process Effects 0.000 claims abstract description 28
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 27
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 25
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 22
- 239000010703 silicon Substances 0.000 claims abstract description 22
- 239000000843 powder Substances 0.000 claims abstract description 18
- 239000007773 negative electrode material Substances 0.000 claims abstract description 15
- 239000010949 copper Substances 0.000 claims abstract description 14
- 229910052802 copper Inorganic materials 0.000 claims abstract description 14
- 238000002156 mixing Methods 0.000 claims abstract description 10
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- 238000005507 spraying Methods 0.000 claims abstract description 8
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- 239000006183 anode active material Substances 0.000 claims description 18
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- 125000004185 ester group Chemical group 0.000 claims description 3
- 239000001307 helium Substances 0.000 claims description 3
- 229910052734 helium Inorganic materials 0.000 claims description 3
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 16
- 238000009830 intercalation Methods 0.000 description 16
- 229910052744 lithium Inorganic materials 0.000 description 16
- 230000002687 intercalation Effects 0.000 description 14
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 12
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- KJFMBFZCATUALV-UHFFFAOYSA-N phenolphthalein Chemical compound C1=CC(O)=CC=C1C1(C=2C=CC(O)=CC=2)C2=CC=CC=C2C(=O)O1 KJFMBFZCATUALV-UHFFFAOYSA-N 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 239000011866 silicon-based anode active material Substances 0.000 description 3
- 230000008719 thickening Effects 0.000 description 3
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 239000007774 positive electrode material Substances 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- CMLFRMDBDNHMRA-UHFFFAOYSA-N 2h-1,2-benzoxazine Chemical compound C1=CC=C2C=CNOC2=C1 CMLFRMDBDNHMRA-UHFFFAOYSA-N 0.000 description 1
- 229910018077 Li 15 Si 4 Inorganic materials 0.000 description 1
- 229910013872 LiPF Inorganic materials 0.000 description 1
- 101150058243 Lipf gene Proteins 0.000 description 1
- 229910002656 O–Si–O Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000010426 asphalt Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
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- 239000011261 inert gas Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 239000004816 latex Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- WHXSMMKQMYFTQS-BKFZFHPZSA-N lithium-12 Chemical compound [12Li] WHXSMMKQMYFTQS-BKFZFHPZSA-N 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
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- 229920006280 packaging film Polymers 0.000 description 1
- 239000012785 packaging film Substances 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
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- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000001029 thermal curing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0419—Methods of deposition of the material involving spraying
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- 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
-
- 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
- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
-
- 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
- H01M2004/021—Physical characteristics, e.g. porosity, surface area
-
- 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
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention discloses a negative electrode for a power battery and a preparation method thereof, which belong to the technical field of new energy batteries, and are characterized in that: the negative electrode comprises a current collector and a negative electrode active material layer, wherein the negative electrode active material layer is fixedly connected to the surface of the current collector through a cold spraying process, and comprises copper, silicon and a rigid polymer; the preparation method of the negative electrode comprises the following steps: s1, crushing a rigid polymer into ultrafine powder; s2, uniformly mixing the superfine powder, the copper powder and the silicon powder according to the weight ratio to obtain mixed powder; s3, spraying the mixed powder on the surface of the current collector through a cold spraying process. The method for preparing the battery cathode by cold spraying has the advantages of simple process and stable process, and the prepared product has better consistency and can effectively ensure the service life of the battery; the product has the characteristics of good uniformity, good conductivity, low impedance, high bonding strength and low battery capacity attenuation.
Description
Technical Field
The invention relates to the technical field of new energy batteries, in particular to a negative electrode for a power battery and a preparation method thereof.
Background
The development of new energy automobiles gradually tends to realize high energy density, high power and rapid charge and discharge, and the development trend also puts higher demands on power batteries of the new energy automobiles.
The power battery of the new energy automobile is assembled by a battery box, a battery management system, a battery module, auxiliary components and the like. The battery box is used for providing protection such as water resistance, dust resistance, vibration resistance and the like for the battery system and also providing a mechanical interface for the installation of the battery system; the battery management system is used for carrying out charge and discharge management and communication management on the battery; the auxiliary components comprise a relay, a fuse, a heating system and the like, and have the main functions of controlling and protecting the circuit; the battery module is a combination body formed by connecting several to hundreds of single batteries in parallel or in series.
The single battery comprises a positive electrode plate, a negative electrode plate, a diaphragm, a tab, electrolyte, a packaging film and the like. The positive electrode plate is generally composed of an aluminum foil and a positive electrode material coated on the aluminum foil, and the negative electrode plate is generally composed of a copper foil and a negative electrode active material layer coated on the copper foil.
Taking a lithium battery as an example, a positive electrode material generally mainly selects high-purity lithium-containing metal oxide, and a negative electrode active material layer generally selects graphite, but with the development of new energy automobiles, the graphite material is used as the most commonly used negative electrode active material layer of the lithium ion battery at present, and has the following defects:
1) The production process flow of the battery pole piece is longer, and comprises the working procedures of ball milling, mixing, coating, rolling, cutting, winding and the like, so that the performance of the battery pole piece is greatly influenced by factors such as material uniformity, slurry dispersion uniformity, coating uniformity, rolling, welding and the like, different single batteries are different in performance aspects such as voltage, capacity, impedance and the like, and the charge and discharge end points of the single batteries used in series-parallel connection are inconsistent, and finally, the consistency and the service life of the batteries are difficult to guarantee; 2) Along with the improvement of the capacity of the positive electrode, corresponding requirements are also provided for the capacity of the negative electrode, more technical routes of silicon-based negative electrodes are adopted at present, but the silicon-based negative electrode has the defects of easy collapse and easy pulverization of the material structure at present, so that the defects of poor cycle performance and quick capacity attenuation of the battery are caused.
In order to solve the problems, the prior art provides a negative electrode for a power battery and a preparation method thereof
Disclosure of Invention
The invention aims to provide a negative electrode for a power battery and a preparation method thereof, and the battery negative electrode prepared by adopting a cold spraying process has the characteristics of good uniformity, good conductivity, low impedance, high bonding strength and low battery capacity attenuation; the process for preparing the battery cathode by cold spraying is simple, the process is stable, and the prepared product has good consistency and can effectively ensure the service life of the battery; in addition, the rigid polymer and the silicon-based material form a network structure, so that a structural frame can be effectively maintained, and enough lithium ion intercalation space is ensured in the anode active material layer all the time, thereby effectively reducing the attenuation speed of the battery capacity.
The technical aim of the invention is realized by the following technical scheme:
the invention provides a negative electrode for a power battery, which comprises a current collector and a negative electrode active material layer, wherein the negative electrode active material layer is fixedly connected to the surface of the current collector through a cold spraying process.
By adopting the technical scheme, the cold spraying process is utilized, so that the anode active material layer sprayed on the current collector has better uniformity, electrical conductivity and thermal conductivity, and the impedance can be effectively reduced; and the cold spraying process can enable the bonding strength of the current collector and the anode active material layer to be higher, so that the growth of a passivation film caused by the crack of the anode active material layer can be effectively avoided, and further the rapid attenuation of the battery capacity can be effectively avoided.
In addition, the cold spraying process can better ensure consistency among lithium ion single batteries, in the prior art, the production process flow of the battery is long, and various working procedures in the production process can lead single batteries in different batches or even in the same batch to generate errors, so that the voltage, capacity, impedance and other performances of the single batteries are different, and the cold spraying technology has the characteristics of stable process and simple working procedure, and can ensure that the charge and discharge end points of the single batteries used in series-parallel connection tend to be consistent to a greater extent, so that the service life of the battery can be ensured.
The invention is further provided with: the anode active material layer includes copper, silicon, and a rigid polymer.
By adopting the technical proposal, silicon is one of the most abundant elements on earth, and can form Li with lithium 12 Si 7 、Li 13 Si 4 、Li 7 Si 3 、Li 22 Si 5 、Li 15 Si 4 The alloy has very high capacity, can be matched with a high-capacity positive electrode, and meets the high-capacity requirement of a power battery; the lithium intercalation voltage of silicon is lower than 0.5V but slightly higher than that of graphite, which means that the situation of surface lithium precipitation basically does not occur during charging, thus having better safety.
During the charge and discharge of the battery, the negative electrode coating material repeatedly undergoes a lithium intercalation and deintercalation process. The general silicon-based material can generate volume expansion in the lithium intercalation process, so that huge internal stress can be generated, and a negative electrode active material layer is cracked and pulverized, so that electrolyte is further contacted with the inside of a coating and reacts, and a passivation film on the surface of an electrode is thickened; the process of thickening the passivation film consumes more lithium ions, thereby reducing the battery capacity; after lithium is removed from the silicon-based material, structural collapse can be generated, and the lithium intercalation space can be greatly reduced, so that the battery capacity can be further reduced; the thickening of the passivation film also has negative influence on the migration process of lithium ions, thereby influencing the charge and discharge efficiency; in addition, the conductivity of silicon itself is not high.
The rigid polymer and the silicon-based material are utilized to form a network structure, firstly, because the structure has more embedding space, the lithium precipitation can be effectively prevented, thus the diaphragm perforation caused by the lithium precipitation can be effectively avoided, and the safety is higher; secondly, the component can provide rigid structural support for the silicon-based anode active material layer, which is beneficial to effectively solving the problem of reduced intercalation space of the silicon-based material caused by structural collapse in the process of repeatedly removing and intercalating lithium, and ensuring that enough lithium ion intercalation space is always provided in the anode active material layer; thirdly, the component can limit the expansion degree of the volume of the silicon-based anode after lithium intercalation, thereby further playing a role of maintaining a structural frame, effectively avoiding cracking and pulverization of a coating caused by overlarge internal stress, effectively preventing thickening of a passivation film, reducing loss of lithium ions and further reducing the speed of capacity attenuation; in addition, the rigid polymer has the characteristic of high temperature resistance, and can keep the frame structure intact at the running temperature of the electrode without breaking and powdering.
The anode active material layers such as copper, rigid polymer and silicon are combined on the current collector through a cold spraying process, and the uniform mixing of the copper, the rigid polymer and the silicon is beneficial to enhancing the bonding strength of the anode active material layers and the current collector, so that the battery capacity can be effectively maintained, and the charge and discharge efficiency can be improved; copper has excellent conductivity, and can effectively improve the conductivity of the negative electrode active material layer.
The invention is further provided with: the rigid polymer contains a plurality of ester groups and a plurality of benzene rings.
By adopting the technical scheme, oxygen and silicon in the rigid polymer can form an O-Si-O covalent bond, so that on one hand, a rigid structural support can be provided for the silicon-based anode active material layer, on the other hand, the expansion degree of the volume of the silicon-based anode after lithium intercalation can be limited, the effect of maintaining a structural frame is achieved, enough lithium ion intercalation space is ensured in the anode active material layer all the time, and the attenuation speed of the battery capacity can be effectively reduced.
The invention is further provided with: the rigid polymer is a polybenzoxazine.
By adopting the technical scheme, the polybenzoxazine has higher thermal stability, thermal oxidation resistance, chemical resistance and higher mechanical strength, can form a framework structure with certain strength with a silicon-based material, ensures that enough lithium ion intercalation space is always reserved in a negative electrode active material layer in the process of repeatedly removing and intercalating lithium, and can effectively reduce the attenuation speed of battery capacity; on the other hand, the component has certain viscosity, and can further improve the cohesive force of the coating, so that the battery capacity can be effectively maintained, and the charge and discharge efficiency can be improved.
The invention is further provided with: the anode active material layer further includes superconducting carbon black.
By adopting the technical scheme, the conductive capacity of the anode coating is further improved, and the electronic conductivity of the anode active material layer is compensated.
The invention is further provided with: the weight ratio of the copper to the silicon to the rigid polymer to the conductive agent is 5-9%:87-93%:2-3%:0-1%.
By adopting the technical scheme, the negative electrode active material layer with good conductivity, large capacitance, good cycle performance of the battery and low capacity decay of the battery is formed.
The invention also provides a preparation method of the negative electrode for the power battery, which is characterized by comprising the following steps:
s1, crushing the rigid polymer into ultrafine powder;
s2, uniformly mixing the superfine powder, copper powder and silicon powder according to the weight ratio to obtain mixed powder;
s3, spraying the mixed powder on the surface of the current collector through a cold spraying process.
By adopting the technical scheme, the battery cathode which has better uniformity, better electric conduction and heat conduction performance, small impedance, high bonding strength, good cycle performance, slow battery capacity decay and consistency is obtained.
The invention is further provided with: the crushing equipment in the step S1 is an air flow crusher or a cryogenic crusher; the device for uniformly mixing in the step S2 is an ultra-energy ball mill.
The invention is further provided with: the particle size of the superfine powder is 5-50 mu m.
By adopting the technical scheme, powder suitable for cold spraying can be obtained.
The invention is further provided with: the cold spraying working gas in the step S3 is one or more of air, nitrogen or helium; the injection pressure of the cold spraying is 1-8 Mpa; the spraying temperature of the cold spraying is 150-1000 ℃; the gas speed of the cold spraying is 150-1100 m/s; the spraying distance of the cold spraying is 5-120 mm.
By adopting the technical scheme, the battery cathode with excellent performance can be obtained.
In summary, the invention has the following beneficial effects:
1. the battery cathode prepared by adopting the cold spraying process has the characteristics of good uniformity, good conductivity, low impedance, high bonding strength and slow capacity fade of the battery; and the process for preparing the battery cathode by cold spraying is simple, the process is stable, and the prepared product has better consistency and can effectively ensure the service life of the battery. 2. According to the invention, a network structure is formed by the rigid polymer and the silicon-based material, so that on one hand, a rigid structural support can be provided for the silicon-based anode active material layer, and on the other hand, the expansion degree of the volume of the silicon-based anode after lithium intercalation can be limited, the function of maintaining a structural frame is achieved, the anode active material layer is ensured to always have enough lithium ion intercalation space, and the attenuation speed of the battery capacity can be effectively reduced.
Drawings
Fig. 1 is a schematic view of the structural position of a battery anode.
In the figure: 1. a positive electrode; 2. a negative electrode; 3. a diaphragm.
Detailed Description
The invention is described in further detail below with reference to the attached drawings and embodiments:
as shown in fig. 1, the structure of the single battery is composed of a shell, a positive electrode, a negative electrode, a diaphragm and the like, and the technical scheme is mainly used for improving the performance of the negative electrode.
Example 1: the negative electrode for the power battery comprises a current collector and a negative electrode active material layer, wherein the negative electrode active material layer is fixedly connected to the surface of the current collector through a cold spraying process, and the current collector is copper foil; the anode active material layer includes copper, silicon, and a rigid polymer; the rigid polymer contains a plurality of ester groups and a plurality of benzene rings; the rigid polymer is polybenzoxazine; the weight ratio of copper, silicon and rigid polymer is 5%:93%:2%.
The preparation method of the polybenzoxazine comprises the following steps: the benzoxazine intermediate is prepared from phenolphthalein, aniline and formaldehyde, and the high-performance polybenzoxazine resin containing phenolphthalein structure is obtained through thermocuring.
Example 2: the difference from example 1 is that: the anode active material layer further includes superconducting carbon black; the weight ratio of copper, silicon, rigid polymer and conductive agent is 6%:90% >: 3%:1%.
Example 3: the difference from example 2 is that: the weight ratio of copper, silicon, rigid polymer and conductive agent is 7%:90% >: 2.5%:0.5%.
Example 4: the difference from example 2 is that: the weight ratio of copper, silicon, rigid polymer and conductive agent is 8%:88% >. 3%:1%.
Example 5: the difference from example 2 is that: the weight ratio of copper, silicon, rigid polymer and conductive agent is 9%:87%:3%:1%.
Example 6: the preparation method of the negative electrode for the power battery comprises the following steps:
s1, crushing a rigid polymer into superfine powder, wherein the particle size of the superfine powder is 5-50 mu m, and the crushing equipment is an air flow crusher or a cryogenic crusher;
s2, mixing the superfine powder, copper powder, silicon powder and a conductive agent in a weight ratio of 6%:90% >: 3%:1% of the powder is uniformly mixed to obtain mixed powder, and the uniform mixing device is an ultra-energy ball mill;
s3, spraying the mixed powder on the surface of the copper foil current collector through a cold spraying process; the cold spraying working gas is one or more of air, nitrogen or helium; the injection pressure of the cold spraying is 1Mpa; the injection temperature of the cold spraying is 1000 ℃; the gas speed of the cold spraying is 1100m/s; the spray distance of the cold spray was 120mm.
Example 7: the difference from example 6 is that: the injection pressure of the cold spraying is 8Mpa; the injection temperature of the cold spraying is 150 ℃; the gas speed of the cold spraying is 150m/s; the spray distance of the cold spray was 5mm.
Example 8: the difference from example 6 is that: the injection pressure of the cold spraying is 4Mpa; the injection temperature of the cold spraying is 500 ℃; the gas speed of the cold spraying is 460m/s; the spray distance of the cold spray was 30mm.
Example 9: the difference from example 6 is that: the injection pressure of the cold spraying is 6Mpa; the injection temperature of the cold spraying is 800 ℃; the gas speed of the cold spraying is 820m/s; the spray distance of the cold spray was 80mm.
Comparative example 1: the difference from example 2 is that: crushing, grading and shaping artificial graphite blocks to obtain artificial graphite micro powder, wherein the weight ratio of asphalt to the artificial graphite micro powder is 1:30, treating for 2 hours at 800 ℃ under the protection of inert gas, cooling to room temperature, scattering, screening and demagnetizing to obtain a sample, mixing the sample, styrene-butadiene rubber latex and carbon black according to the weight ratio of 96:3:1 to prepare micro powder, and coating the micro powder on a copper foil electrode through a cold spraying process.
Comparative example 2: the difference from example 6 is that: the weight ratio of the superfine powder, the copper powder, the silicon powder and the conductive agent is 6 percent: 90% >: 3%:1% of the mixture is prepared into slurry, the slurry is coated on a copper foil, and the slurry is dried to form a negative electrode.
And (3) detection: the prepared product is used as a negative electrode of a lithium ion battery; lithium is used as a counter electrode, and 1M LiPF is used as electrolyte 6 Wherein the mass ratio of the three components is (1:1:1), the diaphragm is a PE/PP/PE composite film, and the mixed liquid is assembled into a simulated battery with the mass ratio of 0.5mA/cm 2 Constant current charge and discharge experiments were carried out at a current density of (0.2C), the charge voltage was limited to 0.01-2.0V, and the first charge specific capacity, the first discharge specific capacity and 1000-cycle performance (%) of the anode active material layer were tested, and the electrochemical performance test results were as follows:
| examples | Specific capacity mAh/g of first discharge | First charge specific capacity mAh/g | Cycle performance at 1000 weeks (%) |
| Example 1 | 1003 | 953 | 82.3 |
| Example 2 | 1013 | 962 | 82.6 |
| Example 6 | 1011 | 964 | 82.1 |
| Example 9 | 1017 | 972 | 82.7 |
| Comparative example 1 | 411 | 399 | 82.7 |
| Comparative example 2 | 865 | 796 | 62.8 |
From the above, the battery cathode prepared by adopting the cold spraying process has the characteristics of good uniformity, good conductivity, low impedance, high bonding strength and slow capacity decay of the battery; and the process for preparing the battery cathode by cold spraying is simple, the process is stable, and the prepared product has better consistency and can effectively ensure the service life of the battery.
In addition, the rigid polymer and the silicon-based material form a network structure, so that a structural frame can be effectively maintained, and enough lithium ion intercalation space is ensured in the anode active material layer all the time, thereby effectively reducing the attenuation speed of the battery capacity.
The present embodiment is only for explanation of the present invention and is not to be construed as limiting the present invention, and modifications to the present embodiment, which may not creatively contribute to the present invention as required by those skilled in the art after reading the present specification, are all protected by patent laws within the scope of claims of the present invention.
Claims (10)
1. The negative electrode for the power battery is characterized in that: the negative electrode comprises a current collector and a negative electrode active material layer, and the negative electrode active material layer is fixedly connected to the surface of the current collector through a cold spraying process.
2. The negative electrode for a power battery according to claim 1, characterized in that: the anode active material layer includes copper, silicon, and a rigid polymer.
3. The negative electrode for a power battery according to claim 2, characterized in that: the rigid polymer contains a plurality of ester groups and a plurality of benzene rings.
4. A negative electrode for a power battery according to claim 3, characterized in that: the rigid polymer is a polybenzoxazine.
5. The negative electrode for a power battery according to claim 2, characterized in that: the anode active material layer further includes superconducting carbon black.
6. The negative electrode for a power battery according to claim 5, wherein: the weight ratio of the copper to the silicon to the rigid polymer to the conductive agent is 5-9%:87-93%:2-3%:0-1%.
7. The method for manufacturing a negative electrode for a power battery according to claim 2, characterized by comprising the steps of:
s1, crushing the rigid polymer into ultrafine powder;
s2, uniformly mixing the superfine powder, copper powder and silicon powder according to the weight ratio to obtain mixed powder;
s3, spraying the mixed powder on the surface of the current collector through a cold spraying process.
8. The method for producing a negative electrode for a power cell according to claim 7, characterized by: the crushing equipment in the step S1 is an air flow crusher or a cryogenic crusher; the device for uniformly mixing in the step S2 is an ultra-energy ball mill.
9. The method for producing a negative electrode for a power cell according to claim 7, characterized by: the particle size of the superfine powder is 5-50 mu m.
10. The method for producing a negative electrode for a power cell according to claim 7, characterized by: the cold spraying working gas in the step S3 is one or more of air, nitrogen or helium; the injection pressure of the cold spraying is 1-8 Mpa; the spraying temperature of the cold spraying is 150-1000 ℃; the gas speed of the cold spraying is 150-1100 m/s; the spraying distance of the cold spraying is 5-120 mm.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160190592A1 (en) * | 2014-12-26 | 2016-06-30 | Semiconductor Energy Laboratory Co., Ltd. | Electrode, power storage device, electronic device, and manufacturing method of electrode |
| CN107706388A (en) * | 2017-10-09 | 2018-02-16 | 北京军秀咨询有限公司 | A kind of preparation method of lithium-ion-power cell and lithium-ion-power cell |
| CN112885997A (en) * | 2020-04-23 | 2021-06-01 | 郑州轻工业大学 | Preparation method and application of novel silicon-based composite porous negative electrode material of lithium ion battery |
| CN114284495A (en) * | 2020-10-01 | 2022-04-05 | 通用汽车环球科技运作有限责任公司 | Electrode assembly and manufacturing method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160190592A1 (en) * | 2014-12-26 | 2016-06-30 | Semiconductor Energy Laboratory Co., Ltd. | Electrode, power storage device, electronic device, and manufacturing method of electrode |
| CN107706388A (en) * | 2017-10-09 | 2018-02-16 | 北京军秀咨询有限公司 | A kind of preparation method of lithium-ion-power cell and lithium-ion-power cell |
| CN112885997A (en) * | 2020-04-23 | 2021-06-01 | 郑州轻工业大学 | Preparation method and application of novel silicon-based composite porous negative electrode material of lithium ion battery |
| CN114284495A (en) * | 2020-10-01 | 2022-04-05 | 通用汽车环球科技运作有限责任公司 | Electrode assembly and manufacturing method thereof |
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| Title |
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| JUN SONG ET AL.: "Preparation of Si-Based Composite Anode for Li-Ion Batteries by Cold Spraying and Its Electrochemical Performance", 《J THERM SPRAY TECH》, 10 March 2023 (2023-03-10), pages 1203 - 1219 * |
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