CN115911375A - Negative pole piece and battery - Google Patents
Negative pole piece and battery Download PDFInfo
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- CN115911375A CN115911375A CN202211393429.2A CN202211393429A CN115911375A CN 115911375 A CN115911375 A CN 115911375A CN 202211393429 A CN202211393429 A CN 202211393429A CN 115911375 A CN115911375 A CN 115911375A
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Images
Classifications
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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
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- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention discloses a negative pole piece and a battery, and relates to the technical field of batteries; the negative pole piece comprises a negative pole piece body and a lithium supplement layer; the lithium supplement layer is arranged on the side surface of the negative pole piece body; the lithium supplement layer comprises metal lithium powder, a conductive agent, a binder, electrolyte lithium salt and a solvent, and the electrolyte lithium salt can be dissolved in the electrolyte of the battery for the negative pole piece. On one hand, the metal lithium powder can replenish lost lithium ions, and the first effect, capacity and cycle performance of the battery are improved; on the other hand, the electrolyte lithium salt can be dissolved in the electrolyte to improve the concentration of the electrolyte, so that the fast charging and power performance of the battery are ensured, the improvement of the concentration of the electrolyte is realized by the later-stage dissolution of the electrolyte lithium salt, the initial concentration of the electrolyte lithium salt is low, the liquid absorption capacity and infiltration capacity of a pole piece can be ensured, and the smooth lithium supplement is ensured; in addition, holes left on the lithium supplement layer after the electrolyte lithium salt is dissolved in the electrolyte can increase the gaps of the pole piece, further improve the infiltration and power performance of the pole piece, and simultaneously improve the cycle and quick charge performance of the battery.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a negative pole piece and a battery.
Background
With the rapid development of new energy automobiles, lithium ion batteries have also been widely paid attention as important components. At present, the requirements of the automobile industry on the lithium ion battery generally need to meet three characteristics, namely long cycle performance, high energy density and excellent quick charge performance.
For long cycle performance, lithium ions lost by an SEI film formed in a first charge and discharge process of a negative electrode plate and lithium ions lost in a cycle process are supplemented by a negative electrode lithium supplementing manner, and a common manner for lithium supplementation of a negative electrode is to coat slurry containing first metal lithium powder on the surface of the negative electrode plate. For high energy densities, this is usually achieved by high coating weights and high compaction densities of the pole pieces. For fast charging performance, this is usually achieved by increasing the electrolyte concentration.
However, the high-concentration electrode solution has high viscosity, and the high coating weight and high compaction density of the electrode plate make the electrode plate difficult to absorb liquid and have poor wettability, so that the lithium supplement operation cannot be effectively carried out, and the cycle performance and the quick charge performance of the battery cannot be simultaneously met. In view of this, the invention is particularly proposed.
Disclosure of Invention
The invention aims to provide a negative pole piece and a battery, which can simultaneously improve the cycle performance and the quick charge performance of the battery.
The embodiment of the invention is realized by the following steps:
in a first aspect, the present invention provides a negative electrode plate, comprising:
a negative plate body;
the lithium supplement layer is arranged on at least one side surface of the negative pole piece body; the lithium supplement layer comprises metal lithium powder, a conductive agent, a binder, electrolyte lithium salt and a solvent, and the electrolyte lithium salt can be dissolved in the electrolyte of the battery for the negative pole piece.
In an optional embodiment, the lithium supplement layer is obtained by coating lithium supplement slurry on the negative electrode sheet body, the lithium supplement slurry includes first metal lithium powder, a first conductive agent, a first binder, a first electrolyte lithium salt and a first solvent, and the mass percentages of the first metal lithium powder, the first conductive agent, the first binder and the first electrolyte lithium salt are 10% -55%, 1% -10%, 1% -40% and 10% -45%, respectively.
In an optional embodiment, the lithium supplement layer is obtained by coating lithium supplement slurry on the negative plate body, drying and rolling;
the solid content of the lithium supplement slurry is 15-55 percent; and/or the coating thickness of the lithium supplementing slurry is 10-40 um; and/or the compression ratio of the rolled lithium supplement layer is 25-45%.
In an alternative embodiment, the first electrolyte lithium salt includes at least one lithium salt having the same electrolyte composition as that in the electrolytic solution of the battery for a negative electrode tab;
and/or the presence of a gas in the gas,
the first electrolyte lithium salt includes LiPF 6 、LiBF 4 One or more of LiBOB, liODFB, liTFSI and LiFSI;
and/or the presence of a gas in the gas,
the first conductive agent comprises at least one of conductive carbon black, conductive graphite, carbon nanotubes, carbon nanofibers and graphene;
and/or the presence of a gas in the gas,
the first binder comprises one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethylcellulose, polyvinyl alcohol and polymethyl methacrylate;
and/or the presence of a gas in the gas,
the first solvent comprises at least one of tetrahydrofuran, paraxylene, octadecyl phosphoric acid, asymmetric ether and cyclic ether.
In an optional embodiment, the lithium supplement layer comprises a lithium supplement base layer and an electrolyte lithium salt layer, the lithium supplement base layer is arranged on at least one side surface of the negative electrode pole piece body, and the electrolyte lithium salt layer is arranged on one side of the lithium supplement base layer, which is far away from the negative electrode pole piece body;
the lithium supplement base layer comprises second metal lithium powder, a second conductive agent, a second binder and a second solvent; the electrolyte lithium salt layer comprises a third conductive agent, a third binder, a second electrolyte lithium salt and a third solvent; and the second electrolyte lithium salt can be dissolved in the electrolyte of the battery for the negative electrode plate.
In an optional embodiment, the lithium supplement base layer is obtained by coating lithium supplement base layer slurry on the negative plate body, and the mass percentages of the second metal lithium powder, the second conductive agent and the second binder in the lithium supplement base layer slurry are 55% -95%, 1% -10% and 1% -40% respectively; the electrolyte lithium salt layer is obtained by coating electrolyte lithium salt slurry on the lithium supplement base layer, and in the electrolyte lithium salt slurry, the mass percentages of the third conductive agent, the third binder and the second electrolyte lithium salt are respectively 1-10%, 1-40% and 55-95%;
and/or the presence of a gas in the gas,
the second electrolyte lithium salt at least comprises one lithium salt with the same electrolyte component in the electrolyte of the battery for the negative pole piece;
and/or the presence of a gas in the gas,
the second electrolyte lithium salt includes LiPF 6 、LiBF 4 One or more of LiBOB, liODFB, liTFSI and LiFSI;
and/or the presence of a gas in the gas,
the second conductive agent and the third conductive agent comprise at least one of conductive carbon black, conductive graphite, carbon nanotubes, carbon nanofibers and graphene;
and/or the presence of a gas in the gas,
the second binder and the third binder comprise one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethylcellulose, polyvinyl alcohol and polymethyl methacrylate;
and/or the presence of a gas in the atmosphere,
the second solvent and the third solvent comprise at least one of tetrahydrofuran, p-xylene, octadecyl phosphoric acid, asymmetric ether, and cyclic ether.
In an alternative embodiment, the electrolyte lithium salt layer is obtained by coating electrolyte lithium salt slurry on the lithium supplement layer, drying and rolling;
the coating thickness of the electrolyte lithium salt slurry is 10-40 um; and/or the compression ratio of the electrolyte lithium salt layer after rolling is 25-45%.
In an optional embodiment, the negative electrode plate body is a copper foil;
or,
the negative pole piece comprises a negative pole current collector and a negative pole active substance layer arranged on the surface of the negative pole current collector, wherein the negative pole active substance layer comprises negative pole active particles, a fourth conductive agent, a fourth binder and a fourth solvent.
In an alternative embodiment, the negative current collector is a copper foil, and the negative active material layer is obtained by coating negative active slurry on the surface of the negative current collector; in the negative electrode active slurry, the mass percentages of the negative electrode active particles, the fourth conductive agent and the fourth binder are 80% -97%: 1% -8%: 1% -5%;
and/or the presence of a gas in the gas,
the negative electrode active particles include at least one of graphite, silicon carbon, and silicon oxide;
and/or the presence of a gas in the gas,
the fourth conductive agent comprises at least one of conductive carbon black, conductive graphite, carbon nanotubes, carbon nanofibers and graphene;
and/or the presence of a gas in the gas,
the fourth binder comprises one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethylcellulose, polyvinyl alcohol and polymethyl methacrylate;
and/or the presence of a gas in the gas,
the fourth solvent comprises at least one of tetrahydrofuran, p-xylene, octadecylphosphoric acid, asymmetric ether, and cyclic ether.
In a second aspect, the present invention provides a battery comprising a negative electrode tab according to any one of the preceding embodiments.
The embodiment of the invention has at least the following advantages or beneficial effects:
the negative pole piece provided by the embodiment of the invention comprises a negative pole piece body and a lithium supplement layer; the lithium supplement layer is arranged on at least one side surface of the negative pole piece body; the lithium supplement layer comprises metal lithium powder, a conductive agent, a binder, electrolyte lithium salt and a solvent, and the electrolyte lithium salt can be dissolved in the electrolyte of the battery for the negative pole piece.
On one hand, through the arrangement of the metal lithium powder and the electrolyte lithium salt in the lithium supplement layer, lithium ions lost by an SEI film formed in the first charge-discharge process of the battery and lithium ions lost in the circulation process can be supplemented, so that the first effect, the capacity and the circulation performance of the battery are improved; on the other hand, the electrolyte lithium salt can be dissolved in the electrolyte to improve the concentration of the electrolyte, so that the quick charging performance and the power performance of the battery can be ensured, and meanwhile, the improvement of the concentration of the electrolyte is realized through the later-stage dissolution of the electrolyte lithium salt, so that the initial concentration of the electrolyte does not need to be too high, the low-concentration electrolyte can ensure the liquid absorption capacity and the infiltration capacity of the pole piece, and the smooth lithium supplement can be ensured; in addition, after the electrolyte lithium salt is dissolved in the electrolyte, a hole structure can be left on the lithium supplement layer, gaps of the pole piece can be increased, and the infiltration and power performance of the pole piece can be further improved, so that the cycle performance and the quick charge performance of the battery can be improved at the same time.
The battery provided by the embodiment of the invention comprises the negative pole piece. Therefore, the battery also has the characteristics of excellent cycle performance and quick charge performance.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.
Fig. 1 is a schematic structural diagram of a negative electrode tab according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of another negative electrode tab according to an embodiment of the present invention.
Reference numerals: 01-negative pole piece; 10-a negative plate body; 101-a negative current collector; 102-negative electrode active material layer; 20-lithium supplement layer; 201-supplementing a lithium base layer; 202-electrolyte lithium salt layer.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are conventional products which are not indicated by manufacturers and are commercially available.
The features and properties of the present invention are described in further detail below with reference to examples.
At present, the requirements of the automobile industry on lithium ion batteries generally need to meet three characteristics, namely long cycle performance, high energy density and excellent quick charge performance. For long cycle performance, lithium ions lost by an SEI film formed in a first charge and discharge process of a negative electrode plate and lithium ions lost in a cycle process are supplemented by a negative electrode lithium supplementing manner, and a common manner for lithium supplementation of a negative electrode is to coat slurry containing first metal lithium powder on the surface of the negative electrode plate. For high energy densities, this is usually achieved by high coating weights and high compaction densities of the pole pieces. For fast charging performance, this is usually achieved by increasing the electrolyte concentration. However, the high-concentration electrode solution has high viscosity, and the high coating weight and high compaction density of the electrode plate make the electrode plate difficult to absorb liquid and have poor wettability, so that the lithium supplement operation cannot be effectively carried out, and the cycle performance and the quick charge performance of the battery cannot be simultaneously met. In view of this, the invention is particularly proposed.
In view of this, embodiments of the present invention provide a negative electrode sheet, which can improve cycle performance and fast charging performance of a battery at the same time, and a battery. The negative electrode tab and the battery comprising the negative electrode tab are described in detail below.
Fig. 1 is a schematic structural diagram of a negative electrode tab 01 according to an embodiment of the present invention. Referring to fig. 1, a negative electrode plate 01 provided in this embodiment includes a negative electrode plate body 10 and a lithium supplement layer 20.
The negative electrode sheet body 10 may be directly selected as a copper foil or may be selected as a composite structure. Exemplarily, in the embodiment of the present invention, the negative electrode sheet body 10 is selected as the negative electrode collector 101 and the negative electrode active material layer 102 provided on at least one side surface of the negative electrode collector 101 in the thickness direction, and preferably both side surfaces are provided with the negative electrode active material layer 102. The negative electrode collector 101 may be selected as a copper foil. The anode active material layer 102 includes anode active particles, a fourth conductive agent, a fourth binder, and a fourth solvent. The negative active particles include at least one of graphite, silicon carbon, and silicon oxide, and may be, for example, graphite. The negative electrode active material layer 102 is obtained by coating a negative electrode active slurry on at least one side surface of the negative electrode current collector 101 in the thickness direction, and then drying and rolling the coated negative electrode active slurry. Wherein, in the negative active slurry, the mass percentage of the negative active particles, the fourth conductive agent and the fourth binder is 80-97%: 1% -8%: 1% -5%, exemplarily, 96% can be selected: 2%:2%, etc.
In an embodiment of the present invention, the fourth conductive agent includes at least one of conductive carbon black, conductive graphite, carbon nanotubes, carbon nanofibers, and graphene. The fourth binder comprises one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethylcellulose, polyvinyl alcohol and polymethyl methacrylate. The fourth solvent comprises at least one of tetrahydrofuran, p-xylene, octadecylphosphoric acid, asymmetric ether, and cyclic ether. Illustratively, the fourth conductive agent may be selected to be conductive carbon black, the fourth binder may be selected to be polyvinylidene fluoride, and the fourth solvent may be selected to be a tetrahydrofuran solvent.
When the negative electrode plate 01 body is prepared, the negative active slurry can be prepared first, then the negative active slurry is coated on the surface of the negative current collector 101, and the negative current collector is dried and rolled. When the negative electrode active slurry is prepared, the fourth conductive agent, the negative electrode active particles and the fourth binder are uniformly mixed according to a ratio, and then the mixture is added into the fourth solvent to be uniformly dispersed.
The lithium supplement layer 20 has two structures, one is shown in fig. 1, the other is shown in fig. 2, both fig. 1 and fig. 2 are illustrated by taking double-sided coating as an example, and in other embodiments, the lithium supplement layer may be coated on one side, which is not limited herein. In detail, in fig. 1, the lithium supplement layer 20 is disposed on at least one side surface of the negative electrode tab 01 body in the thickness direction, and preferably, both side surfaces of the negative electrode tab 01 body in the thickness direction are disposed with the lithium supplement layer 20. The lithium supplement layer 20 specifically includes a first metal lithium powder, a first conductive agent, a first binder, a first electrolyte lithium salt, and a first solvent, and the first electrolyte lithium salt can be dissolved in the electrolyte of the battery for the negative electrode plate 01.
On one hand, by arranging the first lithium metal powder and the first electrolyte lithium salt in the lithium supplement layer 20, lithium ions lost by an SEI film formed in the first charge-discharge process of the battery and lithium ions lost in the circulation process can be supplemented, so that the first efficiency, the capacity and the circulation performance of the battery are improved; on the other hand, the first electrolyte lithium salt can be dissolved in the electrolyte to improve the concentration of the electrolyte, so that the quick charging performance and the power performance of the battery can be ensured, and meanwhile, the concentration of the electrolyte is improved by the later-stage dissolution of the first electrolyte lithium salt, so that the initial concentration of the electrolyte does not need to be too high, the low-concentration electrolyte can ensure the liquid absorption capacity and the infiltration capacity of the pole piece, and the smooth lithium supplement can be ensured; in addition, the first electrolyte lithium salt can be dissolved in the electrolyte to leave a hole structure on the lithium supplement layer 20, so that the gaps of the pole piece can be increased, the infiltration and power performance of the pole piece can be further improved, and the cycle performance and the quick charge performance of the battery can be simultaneously improved.
In this embodiment, the first electrolyte lithium salt includes at least one lithium salt having the same electrolyte component as that in the electrolytic solution of the battery for the negative electrode tab 01. Illustratively, the first electrolyte lithium salt includes LiPF 6 、LiBF 4 One or more of LiBOB, liODFB, liTFSI and LiFSI. Through the setting of first electrolyte lithium salt, can mend lithium jointly with metal lithium, guarantee the cyclicity performance of battery, can dissolve again fast to electrolyte in to improve electrolyte concentration, guarantee the quick charge performance of battery, can also leave the hole at mend lithium layer 20 after dissolving in electrolyte, have certain space with guaranteeing that the pole piece has, thereby soak and the power performance with the abundant improvement pole piece, in order fully to improve the circulation of batteryPerformance and quick-charging performance.
The first conductive agent comprises at least one of conductive carbon black, conductive graphite, carbon nanotubes, carbon nanofibers and graphene. The first binder comprises one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethylcellulose, polyvinyl alcohol and polymethyl methacrylate. The first solvent comprises at least one of tetrahydrofuran, p-xylene, octadecylphosphoric acid, asymmetric ether, and cyclic ether. Illustratively, the first conductive agent may be selected to be conductive carbon black, the first binder may be selected to be polyvinylidene fluoride, and the first solvent may be selected to be a tetrahydrofuran solvent. The first conductive agent may be selected to be different from or the same as the fourth conductive agent, the first binder may be selected to be different from or the same as the fourth binder, and the first solvent may be selected to be different from or the same as the fourth solvent. Preferably, the three are each chosen to be the same.
When the lithium supplement layer 20 is arranged, lithium supplement slurry can be prepared first, then the lithium supplement slurry is coated on the surface of the negative electrode plate 01 body, and the negative electrode plate is dried and rolled. When the lithium supplement slurry is prepared, the first lithium metal powder, the first conductive agent and the first binder are uniformly mixed according to a proportion, and then the mixture is added into the first solvent to be uniformly dispersed.
In the embodiment of the present invention, the first lithium metal powder, the first conductive agent, the first binder, and the first electrolyte lithium salt account for 10% to 55%, 1% to 10%, 1% to 40%, and 10% to 45% by mass, respectively, in the lithium supplement slurry. By controlling the proportion of the first lithium metal powder in the whole lithium supplement slurry, the lithium supplement effect is favorably ensured, so that the first effect, the capacity and the cycle performance of the battery can be fully improved. By controlling the proportion of the first electrolyte lithium salt, the concentration of the electrolyte is favorably ensured, the infiltration capacity of the pole piece is favorably improved, the power performance of the pole piece is ensured, and the cycle performance and the power performance of the battery are fully ensured.
In addition, it should be noted that, in the examples of the present invention, the solid content of the lithium supplement slurry is 15% to 55%. The coating thickness of the lithium supplement slurry is 10-40 um, and the compression ratio of the rolled lithium supplement layer 20 is 25-45%. On one hand, the thickness of the coating is controlled to be 10-40 um, so that electrolyte lithium salt can be conveniently dissolved in electrolyte, the concentration of the electrolyte is improved, and the quick charging performance is ensured. If the coating thickness is thin, the manufacturing and processing are difficult, and if the coating thickness is too thick, the farther the coating thickness direction is from the surface layer, the more difficult the lithium salt is dissolved, and the purpose of ensuring the quick charging performance of the battery cannot be achieved. Meanwhile, the compression ratio of the rolled lithium supplement layer 20 is controlled, so that the dissolution speed of the electrolyte lithium salt is convenient to control, and the electrolyte lithium salt can be smoothly dissolved in the electrolyte to improve the concentration of the electrolyte.
Fig. 2 is another structure of a negative electrode tab 01 according to an embodiment of the present invention. Referring to fig. 2, in the second negative electrode sheet 01, the lithium supplement layer 20 is a composite structure, which is not a single layer film structure. And specifically includes a lithium supplement base layer 201 and an electrolyte lithium salt layer 202.
In detail, the lithium supplement base layer 201 is disposed on at least one side surface of the negative electrode tab 01 body, and may be disposed on, for example, both side surfaces of the negative electrode tab 01 body in the thickness direction. The electrolyte lithium salt layer 202 is arranged on one side of the lithium supplement base layer 201, which is far away from the negative pole piece 01 body. The lithium supplement base layer 201 includes a second lithium metal powder, a second conductive agent, a second binder, and a second solvent. The electrolyte lithium salt layer 202 includes a third conductive agent, a third binder, a second electrolyte lithium salt, and a third solvent; and the second electrolyte lithium salt can be dissolved in the electrolyte of the battery for the negative electrode plate 01.
By the arrangement, on one hand, lithium ions lost by an SEI film formed in the first charge-discharge process of the battery and lithium ions lost in the circulation process can be supplemented by the arrangement of the second metal lithium powder in the lithium supplement base layer 201, so that the first effect, the capacity and the circulation performance of the battery are improved; on the other hand, through the arrangement of the second electrolyte lithium salt in the electrolyte lithium salt layer 202, the second electrolyte lithium salt can be dissolved in the electrolyte to improve the concentration of the electrolyte, the quick charging performance and the power performance of the battery can be ensured, and the improvement of the concentration of the electrolyte is realized through the later dissolution of the second electrolyte lithium salt, so that the initial concentration of the electrolyte does not need to be too high, the low-concentration electrolyte can ensure the liquid absorption capacity and the infiltration capacity of the pole piece, and the smooth proceeding of lithium supplement can be ensured; in addition, the second electrolyte lithium salt can be dissolved in the electrolyte to leave a hole structure on the lithium supplement layer 20, so that the gap of the pole piece can be increased, the infiltration and power performance of the pole piece can be further improved, and the cycle performance and the quick charge performance of the battery can be simultaneously improved. In addition, because the electrolyte lithium salt layer 202 is arranged on the outer side of the lithium supplement base layer 201, the air and the lithium supplement layer 20 can be isolated during battery liquid injection, and the oxidation of the lithium supplement layer 20 is reduced or prevented, so that the later lithium supplement effect is ensured.
In the embodiment of the present invention, the lithium supplement base layer 201 is obtained by coating the slurry of the lithium supplement base layer 201 on the negative electrode sheet body 10, and the electrolyte lithium salt layer 202 is obtained by coating the slurry of the electrolyte lithium salt on the lithium supplement base layer 201. And, the second electrolyte lithium salt includes at least one lithium salt having the same electrolyte composition as that of the electrolyte of the battery for the negative electrode tab 01, and exemplarily, the second electrolyte lithium salt may be selected to include LiPF 6 、LiBF 4 One or more of LiBOB, liODFB, liTFSI and LiFSI. The second conductive agent and the third conductive agent include at least one of conductive carbon black, conductive graphite, carbon nanotubes, carbon nanofibers, and graphene. The second binder and the third binder comprise one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethylcellulose, polyvinyl alcohol and polymethyl methacrylate. The second solvent and the third solvent comprise at least one of tetrahydrofuran, p-xylene, octadecyl phosphoric acid, asymmetric ether, and cyclic ether. Illustratively, the second conductive agent and the third conductive agent may be selected from conductive carbon black, the second binder and the third binder may be selected from polyvinylidene fluoride, and the second solvent and the third solvent may be selected from tetrahydrofuran solvents. The second conductive agent and the third conductive agent may be selected to be different from or the same as the fourth conductive agent and the first conductive agent, the second binder and the third binder may be selected to be different from or the same as the fourth binder and the first binder, and the second solvent and the third solvent may be selected to be different from or the same as the fourth solvent and the first solvent. PreferablyThe four binders, the four conductive agents and the four solvents are respectively selected to be the same.
When the negative electrode plate 01 is prepared, the slurry for the lithium supplement base layer 201 may be coated on the body of the negative electrode plate 01, and the lithium supplement base layer 201 is obtained after drying and rolling. Then, the electrolyte lithium salt slurry is coated on the surface of the lithium supplement base layer 201 slurry, and the electrolyte lithium salt layer 202 is obtained after drying and rolling. When the slurry of the lithium supplement base layer 201 is prepared, the second lithium metal powder, the second conductive agent and the second binder may be mixed in proportion, and then the mixture is added into the second solvent to be uniformly dispersed. When the electrolyte lithium salt slurry is prepared, the third conductive agent, the third binder and the second electrolyte lithium salt can be uniformly mixed according to a proportion, and then the mixture is added into the third solvent to be uniformly dispersed.
In the embodiment of the present invention, the second lithium metal powder, the second conductive agent, and the second binder in the slurry of the lithium supplement base layer 201 account for 55% to 95%, 1% to 10%, and 1% to 40%, respectively, by mass. The electrolyte lithium salt layer 202 is obtained by coating electrolyte lithium salt slurry on the lithium supplement base layer 201, and in the electrolyte lithium salt slurry, the mass percentages of the third conductive agent, the third binder and the second electrolyte lithium salt are respectively 1% -10%, 1% -40% and 55% -95%.
The ratio of the second lithium metal powder in the slurry of the lithium supplement base layer 201 is high, so that the lithium supplement effect can be ensured. In the electrolyte lithium salt layer 202, the proportion of the electrolyte lithium salt is high, so that the wettability of a pole piece can be ensured, and the electrolyte lithium salt and the pole piece are cooperatively matched, so that the cycle performance and the quick charge performance of the battery can be effectively improved.
In the examples of the present invention, the coating thickness of the electrolyte lithium salt slurry was 10 to 40um, and the compression ratio of the electrolyte lithium salt layer after rolling was 25 to 45%. On one hand, the thickness of the electrolyte lithium salt layer 202 is controlled to be 10-40 um, so that the electrolyte lithium salt can be conveniently dissolved in the electrolyte, the concentration of the electrolyte is improved, and the quick charging performance is ensured. If the coating thickness is thin, the manufacturing and processing are difficult, and if the coating thickness is too thick, the farther the coating thickness direction is from the surface layer, the more difficult the lithium salt is dissolved, and the purpose of ensuring the quick charging performance of the battery cannot be achieved. Meanwhile, the compression ratio of the rolled electrolyte lithium salt layer 202 is controlled, so that the dissolution speed of the electrolyte lithium salt is conveniently controlled, and the electrolyte lithium salt can be smoothly dissolved in the electrolyte to improve the concentration of the electrolyte.
In conclusion, the cycle performance and the quick charge performance of the battery can be effectively improved no matter the structure of the negative electrode plate 01 shown in fig. 1 or the structure of the negative electrode plate 01 shown in fig. 2 is adopted.
The embodiment of the invention also provides a battery, which comprises the negative pole piece 01, a shell, a positive pole piece, a separation film and electrolyte. The positive pole piece, the isolating membrane and the negative pole piece 01 are sequentially stacked and laminated or wound to form a pole core, and after the pole core is arranged in the shell, electrolyte is injected to obtain the battery. The battery is prepared by the negative pole piece 01, so that the battery also has the advantages of excellent cycle performance and quick charge performance.
In this embodiment, the positive electrode plate may be an aluminum foil, or may be a composite structure. For example, it may be selected to include a positive electrode current collector and a positive electrode active material layer provided on at least one side surface of the positive electrode current collector in the thickness direction, and preferably both side surfaces are provided with the positive electrode active material layer. The positive current collector may be selected as an aluminum foil. The positive electrode active material layer includes positive electrode active particles, a fifth conductive agent, a fifth binder, and a fifth solvent. The positive active particles include ternary lithium particles, lithium manganate particles, lithium iron phosphate particles, and the like, and the embodiment of the invention selects the ternary material NCM. The positive active material layer is obtained by coating positive active slurry on at least one side surface of a positive current collector along the thickness direction, and then drying and rolling. In the positive active slurry, the fifth conductive agent is selected from at least one of conductive carbon black, conductive graphite, carbon nanotubes, carbon nanofibers and graphene, and the fifth binder is selected from one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethylcellulose, polyvinyl alcohol and polymethyl methacrylate. The fifth solvent comprises at least one of tetrahydrofuran, p-xylene, octadecylphosphoric acid, asymmetric ether, and cyclic ether. Illustratively, the fifth conductive agent may be selected to be conductive carbon black, the fifth binder may be selected to be polyvinylidene fluoride, and the fifth solvent may be selected to be a tetrahydrofuran solvent. Meanwhile, the mass percentages of the positive electrode active particles, the fifth conductive agent and the fifth binder are 80% -97%: 1% -8%: 1% -5%, exemplarily, 96% can be selected: 2%:2%, etc.
The electrolyte can be selected from at least one of organic liquid electrolyte, solid organic electrolyte, solid ceramic electrolyte and gel electrolyte. Illustratively, the electrolyte is an organic liquid electrolyte, and the organic liquid electrolyte includes an electrolyte, a solvent, and an additive. Wherein the electrolyte comprises LiPF 6 、LiBF 4 One or more of LiBOB, liODFB, liTFSI and LiFSI. For example LiPF in particular 6 Mixed with EC/DMC/EMC (V/V = 1.
The isolation membrane is at least one of a polyethylene membrane, a polypropylene membrane, a non-woven fabric membrane, and a composite membrane, a ceramic modified membrane and a PVDF modified membrane thereof. The composite film is formed by a polyethylene film, a polypropylene film and a non-woven fabric, the ceramic modified film is formed by coating a ceramic coating on the surface of a substrate film, and the PVDF modified film is formed by coating PVDF modified films on the surfaces of the polyethylene film, the polypropylene film and the non-woven fabric film. Illustratively, in embodiments of the present invention, the separator is a PE separator.
The above-described battery preparation process and the battery performance are described in detail below by way of specific examples, comparative examples and experimental examples:
example 1
This example provides a battery prepared by the following method:
s1: the preparation of the negative electrode plate 01 specifically comprises the following steps:
s11: mixing silicon carbon, conductive carbon black and polyvinylidene fluoride according to a proportion of 96%:2%:2 percent of the mixture is added into tetrahydrofuran solvent to be dispersed evenly to obtain cathode active slurry; coating the negative active slurry on two side surfaces in the thickness direction of the copper foil, and drying and rolling to obtain a negative pole piece 01 body;
s12: respectively mixing 50% and 10% of first metal lithium powder, conductive carbon black, polyvinylidene fluoride and lithium hexafluorophosphate in percentage by mass: 30%: mixing 10% of the lithium ion battery powder uniformly, adding the mixture into a tetrahydrofuran solvent, dispersing uniformly, and controlling the solid content to be 35% +/-2% to obtain lithium supplement slurry; and coating the lithium supplement slurry on the surface of the negative electrode plate 01 body, drying and rolling to obtain the negative electrode plate 01 shown in figure 1. Wherein the coating thickness of the lithium supplement slurry is 20um; the compression ratio of the lithium supplement layer 20 after rolling is 30%.
S2: the preparation of the positive pole piece specifically comprises the following steps:
mixing an NCM ternary material, conductive carbon black and polyvinylidene fluoride according to a proportion of 96%:2%:2 percent of the mixture is added into tetrahydrofuran solvent to be dispersed evenly to obtain positive active slurry; and coating the positive active slurry on two side surfaces of the aluminum foil in the thickness direction, and drying and rolling to obtain the positive pole piece.
S3: the preparation of the battery specifically comprises the following steps:
LiPF 6 to a volume ratio of 1:1:1, mixing DMC, EMC and FEC to obtain 1.0mol/L electrolyte; assembling the positive pole piece, the negative pole piece 01 and the isolating membrane to obtain a pole core, placing the pole core in a shell, drying, injecting the prepared electrolyte, and then carrying out processes such as packaging, standing, formation, capacity grading and the like to obtain the lithium ion secondary battery.
Example 2
This example provides a battery whose manufacturing method differs from that of example 1 in that:
in step S12, the lithium replenishment slurry is passed through a 50%, 8%:30%: and mixing 12% of first metal lithium powder, conductive carbon black, polyvinylidene fluoride and lithium hexafluorophosphate, and dispersing into a tetrahydrofuran solvent to obtain the composite material.
Example 3
This example provides a battery whose manufacturing method differs from that of example 1 in that:
in step S12, the lithium replenishment slurry is passed through a 50%, 5%:21%: and mixing 24% of first metal lithium powder, conductive carbon black, polyvinylidene fluoride and lithium hexafluorophosphate, and dispersing into a tetrahydrofuran solvent to obtain the composite material.
Example 4
This example provides a battery whose manufacturing method differs from that of example 1 in that:
in step S12, the lithium replenishment slurry is passed through a 50%, 5%:9%: mixing 36% of first metal lithium powder, conductive carbon black, polyvinylidene fluoride and lithium hexafluorophosphate, and dispersing into a tetrahydrofuran solvent to obtain the composite material.
Example 5
This example provides a battery whose manufacturing method differs from that of example 1 in that:
in step S12, the lithium replenishment slurry is passed through a 50%, 2%:3%: and mixing 45% of first lithium metal powder, conductive carbon black, polyvinylidene fluoride and lithium hexafluorophosphate, and dispersing into a tetrahydrofuran solvent to obtain the composite material.
Example 6
This example provides a battery, the manufacturing method of which differs from that of example 1 in that:
in step S12, the lithium replenishment slurry is passed through a lithium ion battery of 55%, 5%:16%: and mixing 24% of first lithium metal powder, conductive carbon black, polyvinylidene fluoride and lithium hexafluorophosphate, and dispersing into a tetrahydrofuran solvent to obtain the composite material.
Example 7
This example provides a battery, the manufacturing method of which differs from that of example 1 in that:
in step S12, the lithium replenishment slurry is passed through a mixer of 26%, 10%:40%: and mixing 24% of first metal lithium powder, conductive carbon black, polyvinylidene fluoride and lithium hexafluorophosphate, and dispersing into a tetrahydrofuran solvent to obtain the composite material.
Example 8
This example provides a battery whose manufacturing method differs from that of example 1 in that:
step S12 specifically includes: uniformly mixing 70%, 5% and 25% of second metal lithium powder, conductive carbon black and polyvinylidene fluoride according to mass percentage, adding the mixture into a tetrahydrofuran solvent, uniformly dispersing, and controlling the solid content to be 35% +/-2% to obtain a lithium supplement base layer 201 slurry; coating the slurry of the lithium supplement base layer 201 on the surface of the negative electrode plate 01 body, drying and rolling to obtain the lithium supplement base layer 201; uniformly mixing 5%, 25% and 70% of conductive carbon black, polyvinylidene fluoride and lithium hexafluorophosphate according to mass percentage, adding the mixture into a tetrahydrofuran solvent for uniform dispersion, and controlling the solid content to be 35% +/-2% to obtain electrolyte lithium salt slurry; coating the electrolyte lithium salt slurry on the surface of the lithium supplement base layer 201, drying and rolling to obtain a negative electrode plate 01 shown in fig. 2; wherein the coating thickness of the electrolyte lithium salt layer 202 is 10um; the compression ratio of the electrolyte lithium salt layer 202 after rolling is 30%.
Example 9
This example provides a battery, which was prepared by a method different from that of example 8 in that:
in step S12, the electrolyte lithium salt slurry includes 10%, 35%, and 55% of conductive carbon black, polyvinylidene fluoride, and lithium hexafluorophosphate.
Example 10
This example provides a battery, which was prepared by a method different from that of example 8 in that:
in step S12, the electrolyte lithium salt slurry includes 5%, 15%, and 80% of conductive carbon black, polyvinylidene fluoride, and lithium hexafluorophosphate.
Example 11
This example provides a battery, the manufacturing method of which differs from that of example 8 in that:
in step S12, the electrolyte lithium salt slurry includes 1% to 10%, 1% to 40%, and 95% of conductive carbon black, polyvinylidene fluoride, and lithium hexafluorophosphate.
Example 12
This example provides a battery, the manufacturing method of which differs from that of example 8 in that:
in step S12, the lithium supplement base layer 201 slurry includes 95%, 2%, 3% of second metal lithium powder, conductive carbon black, and polyvinylidene fluoride.
Example 13
This example provides a battery, the manufacturing method of which differs from that of example 8 in that:
in step S12, the slurry of the lithium supplement base layer 201 includes 55%, 10%, 35% of the second metal lithium powder, conductive carbon black, and polyvinylidene fluoride.
Comparative example 1
Comparative example 1 provides a battery, which is different from the preparation method of the battery provided in example 1 in that:
in step S12, the lithium supplement slurry includes metal lithium powder, conductive carbon black, and polyvinylidene fluoride in a mass ratio of 70 6 The concentration is 1.0mol/L.
Comparative example 2
Comparative example 2 provides a battery, which is different from the preparation method of the battery provided in example 1 in that:
in step S12, the lithium replenishment slurry is passed through a 40%, 5%:5%: and mixing 50% of first metal lithium powder, conductive carbon black, polyvinylidene fluoride and lithium hexafluorophosphate, and dispersing into a tetrahydrofuran solvent to obtain the composite material.
Comparative example 3
Comparative example 3 provides a battery, which is different from the method for preparing the battery provided in example 1 in that:
in step S12, the lithium replenishment slurry is passed through a 50%, 5%:40%:5% of first metal lithium powder, conductive carbon black, polyvinylidene fluoride and lithium hexafluorophosphate are mixed and dispersed in a tetrahydrofuran solvent to obtain the lithium-ion battery.
Comparative example 4
Comparative example 4 provides a battery, which is different from the method for preparing the battery provided in example 8 in that:
in step S12, the electrolyte lithium salt slurry is obtained by dispersing 1%, and 98% of conductive carbon black, polyvinylidene fluoride, and lithium hexafluorophosphate in a tetrahydrofuran solvent.
Comparative example 5
Comparative example 5 provides a battery, which is different from the method for preparing the battery provided in example 8 in that:
in step S12, the electrolyte lithium salt slurry is obtained by dispersing 10%, 40%, and 50% of conductive carbon black, polyvinylidene fluoride, and lithium hexafluorophosphate in a tetrahydrofuran solvent.
Comparative example 6
Comparative example 6 provides a battery, which is different from the preparation method of the battery provided in comparative example 1 in that:
the concentration of electrolyte LiPF6 in the electrolyte is 1.3mol/L.
Experimental example 1
The batteries prepared in examples 1 to 13 and comparative examples 1 to 6 were subjected to a capacity and first-effect test, a DCR test, and a cycle performance test; the capacity and first-effect test process comprises the steps of standing the battery for 12 hours at 45 ℃ after liquid injection, then charging the battery to 3.40V at 0.02C, charging the battery to 3.75V at 0.1C, discharging the battery for two times, then charging the battery to 4.35V at 0.5C with constant current and constant voltage, cutting off 0.05C, and then discharging the battery to 2.8V at 1C to obtain discharge capacity; the first effect is the total charge capacity over the first discharge capacity. The DCR test was performed by adjusting the cell to 50% SOC,3C, 10s of discharge at 25 deg.C, and calculating the DCR value using the difference between the open circuit voltage before discharge and the voltage at 10s of discharge, as compared to the discharge current. The cycle test process comprises charging at 25 deg.C under constant current and constant voltage at 1C to 4.35V, stopping at 0.05C, standing for 30min, discharging at 1C to 2.8V, and standing for 30min. And repeating the steps to calculate the capacity retention rate. The test structure is shown in table 1.
TABLE 1 test results
According to the comparison between the examples 1 to 13 of the present invention and the comparative examples 1 to 6, the first effect, the capacity and the cycle performance of the battery can be effectively improved no matter the structure of the negative electrode plate 01 shown in fig. 1 or the structure of the negative electrode plate 01 shown in fig. 2 is adopted, and the smooth performance of the lithium supplement operation can be ensured by effectively improving the liquid absorption capacity and the infiltration capacity of the negative electrode plate 01, so as to fully improve the cycle performance and the quick charge performance of the battery.
And specifically, according to the comparison between examples 1 to 7 and comparative example 1, by adopting the structure of the first negative electrode plate 01, and adding the electrolyte lithium salt in the lithium supplement layer 20, the concentration of the electrolyte in the electrolyte can be effectively increased, so that the DCR value can be effectively reduced, and the battery capacity can be ensured. According to the comparison between examples 8 to 13 and comparative example 1, by adopting the structure of the second negative electrode plate 01, the concentration of the electrolyte in the electrolyte can be effectively increased by adding the electrolyte lithium salt in the electrolyte lithium salt layer 202, so that the DCR value is effectively reduced, and the battery capacity, the cycle performance and the quick charge performance are ensured.
According to the comparison among examples 1 to 5, comparative example 3 and comparative example 4, it can be seen that the DCR value can be improved by increasing the proportion of the lithium salt in the electrolyte and increasing the concentration of the electrolyte in the electrolyte solution when the proportion of the lithium metal powder is constant by using the first negative electrode sheet 01 structure. However, when the proportion of the electrolyte lithium salt exceeds 24%, the electrolyte concentration is high due to the excessively high electrolyte content, the wettability of the electrolyte is relatively reduced, and the pole piece cannot be sufficiently wetted, so that the cycle data is relatively poor at the beginning of the cycle, but the pole piece can be sufficiently wetted after the cycle is 10, and the capacity and the cycle performance of the battery can be ensured. Meanwhile, the content of the electrolyte lithium salt of comparative example 3 is too low, and the content of the electrolyte lithium salt of comparative example 4 is too high, and the ability to improve the performance of the battery is not as good as in examples 1 to 5. Similarly, according to the comparison among examples 8 to 13, comparative example 5 and comparative example 6, it can be seen that the DCR value can be improved by increasing the proportion of the electrolyte lithium salt and increasing the concentration of the electrolyte in the electrolyte solution by using the second negative electrode tab 01 structure. However, when the proportion of the electrolyte lithium salt exceeds 70%, the electrolyte concentration is high due to the excessively high electrolyte content, the wettability of the electrolyte is relatively reduced, and the pole piece cannot be sufficiently wetted, so that the cycle data is relatively poor at the beginning of the cycle, but the pole piece can be sufficiently wetted after the cycle is 10, and the capacity and the cycle performance of the battery can be ensured. Meanwhile, the electrolyte lithium salt content of comparative example 4 was too high, and the electrolyte lithium salt content of comparative example 5 was too low, and the ability to improve the cycle performance and the quick charge performance of the battery was inferior to examples 1 to 5.
It can be seen from the comparison among examples 3, 6 and 7 and the comparison among examples 8, 12 and 13 that, when the content of the electrolyte lithium salt is constant, the metallic lithium powder can effectively replenish lost lithium ions, and thus can effectively improve the cycle performance of the battery.
According to the comparison between example 3 and comparative example 6, although the final concentration of the electrolyte is the same, the DCR, the capacity and the cycle performance are more worried in example 3, which shows that the cycle performance and the quick charge performance of the battery can be improved by adding the electrolyte lithium salt to generate a void structure to sufficiently ensure the wetting effect of the pole piece.
As can be seen from examples 1 to 7 and examples 8 to 13, the second negative electrode tab 01 can achieve the effect of increasing the concentration of the electrolyte in the first negative electrode tab 01 when the coating thickness of the electrolyte lithium salt is small. And no matter the structure of the first negative pole piece 01 or the structure of the second negative pole piece 01 is adopted, the cycle performance and the quick charging performance of the battery can be effectively improved.
In summary, in the embodiments of the present invention, on one hand, by arranging the metal lithium powder and the electrolyte lithium salt in the lithium supplement layer 20, lithium ions lost by the SEI film formed in the first charge and discharge process of the battery and lithium ions lost in the cycle process can be supplemented, so as to improve the first efficiency, capacity and cycle performance of the battery; on the other hand, the electrolyte lithium salt can be dissolved in the electrolyte to improve the concentration of the electrolyte, so that the fast charging performance and the power performance of the battery can be ensured, and meanwhile, the concentration of the electrolyte is improved by the later-stage dissolution of the electrolyte lithium salt, so that the initial concentration of the electrolyte is not too high, the low-concentration electrolyte can ensure the liquid absorption capacity and the infiltration capacity of a pole piece, and the smooth lithium supplement can be ensured; in addition, after the electrolyte lithium salt is dissolved in the electrolyte, a hole structure can be left on the lithium supplement layer 20, gaps of the pole piece can be increased, and the infiltration and power performance of the pole piece can be further improved, so that the cycle performance and the quick charge performance of the battery can be improved at the same time.
In summary, the embodiment of the invention provides the negative electrode plate 01 and the battery, which can improve the cycle performance and the quick charge performance of the battery at the same time.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A negative electrode sheet, comprising:
a negative plate body;
the lithium supplement layer is arranged on at least one side surface of the negative pole piece body; the lithium supplement layer comprises metal lithium powder, a conductive agent, a binder, electrolyte lithium salt and a solvent, and the electrolyte lithium salt can be dissolved in the electrolyte of the battery for the negative pole piece.
2. The negative electrode tab of claim 1, wherein:
the lithium supplement layer is obtained by coating lithium supplement slurry on the negative plate body, the lithium supplement slurry comprises first metal lithium powder, a first conductive agent, a first binder, first electrolyte lithium salt and a first solvent, and the first metal lithium powder, the first conductive agent, the first binder and the first electrolyte lithium salt respectively account for 10% -55%, 1% -10%, 1% -40% and 10% -45% by mass.
3. The negative electrode tab of claim 2, wherein:
the solid content of the lithium supplement slurry is 15-55 percent; and/or the coating thickness of the lithium supplementing slurry is 10-40 um; and/or the compression ratio of the rolled lithium supplement layer is 25-45%.
4. The negative electrode tab of claim 2, wherein:
the first electrolyte lithium salt at least comprises one lithium salt with the same electrolyte component in the electrolyte of the battery for the negative pole piece;
and/or the presence of a gas in the gas,
the first electrolyte lithium salt comprises LiPF 6 、LiBF 4 One or more of LiBOB, liODFB, liTFSI and LiFSI;
and/or the presence of a gas in the gas,
the first conductive agent comprises at least one of conductive carbon black, conductive graphite, carbon nanotubes, carbon nanofibers and graphene;
and/or the presence of a gas in the gas,
the first binder comprises one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethylcellulose, polyvinyl alcohol and polymethyl methacrylate;
and/or the presence of a gas in the gas,
the first solvent comprises at least one of tetrahydrofuran, p-xylene, octadecyl phosphoric acid, asymmetric ether and cyclic ether.
5. The negative electrode tab of claim 1, wherein:
the lithium supplement layer comprises a lithium supplement base layer and an electrolyte lithium salt layer, the lithium supplement base layer is arranged on at least one side surface of the negative pole piece body, and the electrolyte lithium salt layer is arranged on one side, away from the negative pole piece body, of the lithium supplement base layer;
the lithium supplement base layer comprises second metal lithium powder, a second conductive agent, a second binder and a second solvent; the electrolyte lithium salt layer comprises a third conductive agent, a third binder, a second electrolyte lithium salt and a third solvent; and the second electrolyte lithium salt can be dissolved in the electrolyte of the battery for the negative electrode plate.
6. The negative electrode tab of claim 5, wherein:
the lithium supplement base layer is obtained by coating lithium supplement base layer slurry on the negative plate body, and the second metal lithium powder, the second conductive agent and the second binder in the lithium supplement base layer slurry respectively account for 55% -95%, 1% -10% and 1% -40% by mass; the electrolyte lithium salt layer is obtained by coating electrolyte lithium salt slurry on the lithium supplement base layer, and in the electrolyte lithium salt slurry, the third conductive agent, the third binder and the second electrolyte lithium salt account for 1-10% by mass, 1-40% by mass and 55-95% by mass respectively;
and/or the presence of a gas in the gas,
the second electrolyte lithium salt at least comprises one lithium salt with the same electrolyte component in the electrolyte of the battery for the negative pole piece;
and/or the presence of a gas in the atmosphere,
the second electrolyte lithium salt includes LiPF 6 、LiBF 4 One or more of LiBOB, liODFB, liTFSI and LiFSI;
and/or the presence of a gas in the gas,
the second conductive agent and the third conductive agent both comprise at least one of conductive carbon black, conductive graphite, carbon nanotubes, carbon nanofibers and graphene;
and/or the presence of a gas in the gas,
the second binder and the third binder respectively comprise one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethylcellulose, polyvinyl alcohol and polymethyl methacrylate;
and/or the presence of a gas in the gas,
the second solvent and the third solvent both comprise at least one of tetrahydrofuran, p-xylene, octadecyl phosphoric acid, asymmetric ether and cyclic ether.
7. The negative electrode tab of claim 5, wherein:
the electrolyte lithium salt layer is obtained by coating electrolyte lithium salt slurry on the lithium supplement base layer, drying and rolling;
the coating thickness of the electrolyte lithium salt slurry is 10-40 um; and/or the compression ratio of the electrolyte lithium salt layer after rolling is 25-45%.
8. The negative electrode tab according to any one of claims 1 to 7, wherein:
the negative pole piece body is a copper foil;
or,
the negative pole piece comprises a negative pole current collector and a negative pole active substance layer arranged on the surface of the negative pole current collector, wherein the negative pole active substance layer comprises negative pole active particles, a fourth conductive agent, a fourth binder and a fourth solvent.
9. The negative electrode tab according to claim 8, wherein:
the negative current collector is copper foil, and the negative active substance layer is obtained by coating negative active slurry on the surface of the negative current collector; in the negative electrode active slurry, the mass percentages of the negative electrode active particles, the fourth conductive agent and the fourth binder are 80-97%: 1% -8%: 1% -5%;
and/or the presence of a gas in the gas,
the negative electrode active particles include at least one of graphite, silicon carbon, and silicon oxide;
and/or the presence of a gas in the atmosphere,
the fourth conductive agent comprises at least one of conductive carbon black, conductive graphite, carbon nano tubes, carbon nano fibers and graphene;
and/or the presence of a gas in the gas,
the fourth binder comprises one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethylcellulose, polyvinyl alcohol and polymethyl methacrylate;
and/or the presence of a gas in the gas,
the fourth solvent comprises at least one of tetrahydrofuran, p-xylene, octadecyl phosphoric acid, asymmetric ether and cyclic ether.
10. A battery comprising the negative electrode sheet according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211393429.2A CN115911375A (en) | 2022-11-08 | 2022-11-08 | Negative pole piece and battery |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003217568A (en) * | 2002-01-17 | 2003-07-31 | Mitsubishi Heavy Ind Ltd | Positive electrode for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery |
| CN109103419A (en) * | 2018-07-16 | 2018-12-28 | 合肥国轩高科动力能源有限公司 | A kind of negative electrode of lithium ion battery mends lithium electrode and preparation method thereof |
| CN112599723A (en) * | 2020-12-03 | 2021-04-02 | 天津市捷威动力工业有限公司 | Lithium-supplement negative pole piece, preparation method thereof and lithium ion battery |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003217568A (en) * | 2002-01-17 | 2003-07-31 | Mitsubishi Heavy Ind Ltd | Positive electrode for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery |
| CN109103419A (en) * | 2018-07-16 | 2018-12-28 | 合肥国轩高科动力能源有限公司 | A kind of negative electrode of lithium ion battery mends lithium electrode and preparation method thereof |
| CN112599723A (en) * | 2020-12-03 | 2021-04-02 | 天津市捷威动力工业有限公司 | Lithium-supplement negative pole piece, preparation method thereof and lithium ion battery |
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