CN114583295A - Negative plate, preparation method thereof and battery - Google Patents
Negative plate, preparation method thereof and battery Download PDFInfo
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- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
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Abstract
The invention provides a negative plate, a preparation method thereof and a battery. According to the invention, the hole structure is arranged in the negative electrode active material layer, the metal lithium is embedded in the hole structure, the electrochemical performance of the battery cell is not influenced while lithium is supplemented, and the metal lithium is embedded in the hole structure, so that the risk that lithium is separated out to penetrate through the diaphragm to cause short circuit of the battery cell is avoided in the battery cell circulation process, and the safety of the battery cell in the circulation process is effectively improved.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a negative plate, a preparation method thereof and a battery.
Background
Lithium ion batteries have received much attention due to their advantages such as high energy density and good cycle performance. With the popularization of mobile internet devices, the popularization of electric automobiles and other electric vehicles, and the development of aerospace technologies such as unmanned aerial vehicles and space detectors, the performance of lithium ion batteries is facing higher development requirements, and how to improve the energy density and the quick charge performance of the lithium ion batteries becomes a key breakthrough direction of high-performance lithium ion batteries.
Currently, high gram-capacity silicon-based negative electrode materials are generally used to increase the energy density of the battery. However, the high-gram-capacity silicon-based negative electrode material has low first efficiency, and the energy density of 400Wh/kg is difficult to achieve under the design condition of a limit process, so that the negative electrode material needs to be pre-lithiated, the first efficiency is improved, and the energy density of the battery is further improved. The prelithiation, i.e. the lithium supplement technology, is one of the important strategies to solve the problem of low first efficiency of the negative electrode material.
The prelithiation strategy is currently mainly applied to lithium ion batteries, and the main purpose of the prelithiation strategy is to offset lithium ions consumed in the formation process of the lithium ion batteries, so that the first efficiency of the batteries is improved. The negative electrode pre-lithiation is to mix lithium powder and a negative electrode active material together and coat the mixture on a negative electrode current collector, or press a lithium belt on a negative electrode active material layer, and through liquid injection pre-lithium intercalation reaction, a lithium source of a lithium supplementing material is supplemented into a battery to compensate active lithium lost by first charge and discharge, but a hole is left in the negative electrode active material layer after lithium is dissolved and supplemented, a side reaction residue of metal lithium and electrolyte can damage the interface of a negative electrode piece, and the transmission of electrons and lithium ions in the negative electrode active material layer can be hindered by the existence of a side reaction product and the hole, so that the electrochemical performance of the battery is influenced.
Disclosure of Invention
The invention aims to solve the problem that the residue and holes of a lithium supplement material influence the electrochemical performance of a battery while lithium is supplemented by a prelithiation method in the prior art.
In order to solve the above problems, a first aspect of the present invention provides a negative electrode sheet, including a negative electrode current collector and a negative electrode active material layer disposed on at least one side surface of the negative electrode current collector, where the negative electrode active material layer has a pore structure, and metal lithium is embedded in the pore structure.
Further, the plurality of pore structures are arranged perpendicular to the negative electrode current collector, and the plurality of pore structures are uniformly distributed in the negative electrode active material layer.
Further, the hole structure is a blind hole, and the depth of the hole structure is not more than one third of the thickness of the negative electrode active material layer.
Furthermore, the metal lithium is a lithium block, and the embedding depth of the metal lithium is smaller than the depth of the hole structure.
Further, the porosity of the anode active material layer is not higher than 60%.
Further, the porosity of the anode active material layer is 5% to 20%.
Further, the pore size of the pore structure is not more than 5 mm.
Further, the pore size of the pore structure is 100 μm to 1.5 mm.
The second aspect of the present invention provides a battery, including a battery cell, where the battery cell includes a positive plate, a negative plate, and a diaphragm disposed between the positive plate and the negative plate, the positive plate, the negative plate, and the diaphragm are stacked or wound to form the battery cell, and the negative plate is the negative plate of any one of the first aspects.
The third aspect of the invention provides a preparation method of a negative plate, which comprises the following steps:
providing a negative current collector, coating negative active material slurry on the surface of the negative current collector, and forming a negative active material layer after curing;
providing a pore structure on a surface of the negative electrode active material layer;
and filling metal lithium into the hole structure to obtain the negative plate.
According to the negative plate, the hole structure is arranged in the negative active material layer, the metal lithium is embedded in the hole structure, after liquid injection, lithium ions are pre-embedded into the negative active material layer around the hole structure, the gram capacity of the metal lithium is high, active lithium lost by first charge and discharge can be compensated, the energy density of the battery cell is improved, an inactive solid product generated by reaction of the metal lithium and an electrolyte is contracted in the hole structure and cannot be gathered on the surface of the negative electrode, and a cavity formed by the metal lithium after reaction with the electrolyte is also positioned in the hole structure and cannot damage the negative active material layer, so that the inactive solid product and the cavity cannot influence the electrolyte transmission between the negative plate and a diaphragm, the DCIR of the battery cell with the pre-embedded lithium on the surface and the consumption of the electrolyte are reduced, and the cycle performance of the battery cell is improved; according to the embodiment of the application, the hole structure is arranged in the negative electrode active material layer, the metal lithium is embedded in the hole structure, the electrochemical performance of the battery cell is not influenced while lithium is supplemented, the metal lithium is embedded in the hole structure, the risk that the lithium is separated out to penetrate through the diaphragm to cause short circuit of the battery cell is avoided in the battery cell circulation process, and the safety of the battery cell in the circulation process is effectively improved; in addition, after lithium is pre-embedded, the hole structure in the negative active material layer is filled with electrolyte, so that the storage and transportation of the electrolyte are facilitated, the liquid retention capacity of the electrolyte can be improved, the diffusion distance of lithium ions is reduced, the transmission speed of the lithium ions is increased, and the power performance, the quick charging performance and the cycle performance of a battery cell are facilitated to be improved.
Drawings
Fig. 1 is a schematic structural diagram of a negative electrode sheet according to an embodiment of the present invention;
fig. 2 is a process flow chart of preparing a negative plate according to an embodiment of the invention.
Description of reference numerals:
1-negative current collector; 2-a negative electrode active material layer; 3-pore structure; 4-metallic lithium.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
In addition, the terms "comprising," "including," "containing," and "having" are intended to be non-limiting, i.e., that other steps and other ingredients can be added that do not affect the results. Materials, equipment and reagents are commercially available unless otherwise specified.
In addition, although the invention has described the forms of S1, S2, S3 and the like for each step in the preparation, the description is only for ease of understanding, and the forms of S1, S2, S3 and the like do not represent the limitation of the sequence of each step.
In order to solve the above technical problems, embodiments of the present invention provide a negative electrode sheet, a battery cell, and a method for manufacturing the negative electrode sheet, which aim to solve the above problems.
Fig. 1 is a schematic structural diagram of a negative electrode sheet in an embodiment of the present invention. With reference to fig. 1, a first aspect of the embodiments of the present application provides a negative electrode sheet, including a negative electrode current collector 1 and a negative electrode active material layer 2 disposed on at least one side surface of the negative electrode current collector 1, where the negative electrode active material layer has a pore structure 3, and metal lithium 4 is embedded in the pore structure 3.
In the negative plate provided in the embodiment of the application, the hole structure is arranged in the negative active material layer, and the metal lithium is embedded in the hole structure, after liquid injection, lithium ions pre-embed lithium into the negative active material layer around the hole structure, the gram capacity of the metal lithium is high, active lithium which is lost by first charge and discharge can be compensated, the energy density of the battery cell is improved, an inactive solid product generated by the reaction of the metal lithium and an electrolyte shrinks in the hole structure and cannot be gathered on the surface of the negative electrode, and a cavity formed by the metal lithium after the reaction with the electrolyte is also located in the hole structure, so that the negative active material layer cannot be damaged, the inactive solid product and the cavity cannot influence the electrolyte transmission between the negative plate and the diaphragm, the consumption of DCIR and the electrolyte of the battery cell with the pre-embedded lithium on the surface is favorably reduced, and the cycle performance of the battery cell is improved; according to the embodiment of the application, the hole structure is arranged in the negative electrode active material layer, the metal lithium is embedded in the hole structure, the electrochemical performance of the battery cell is not influenced while lithium is supplemented, the metal lithium is embedded in the hole structure, the risk that the lithium is separated out to penetrate through the diaphragm to cause short circuit of the battery cell is avoided in the battery cell circulation process, and the safety of the battery cell in the circulation process is effectively improved; in addition, after lithium is pre-embedded, the hole structure in the negative active material layer is filled with electrolyte, so that the storage and transportation of the electrolyte are facilitated, the liquid retention capacity of the electrolyte can be improved, the diffusion distance of lithium ions is reduced, the transmission speed of the lithium ions is increased, and the power performance, the quick charging performance and the cycle performance of a battery cell are facilitated to be improved.
The negative electrode active material layer 2 has a plurality of pore structures 3 therein, and these pore structures 3 are distinguishable by naked eyes, that is, the pore structures 3 can be sensed by eyes or with the aid of a common magnifier; these pore structures 3 are uniformly distributed in the anode active material layer 2, and the pore structures 3 are in a regular shape, for example: the pore structures are in regular shapes such as circles, triangles, rectangles, pentagons, hexagons or rhombuses. From this, pore structure 3 evenly distributed is in negative pole active material layer 2, and the distribution of unorganized not having, and lithium can be mended more evenly to further reduce lithium ion's diffusion distance, promote the multiplying power performance and the power performance of electric core.
The porosity of the anode active material layer 2 is not more than 60%, for example: the porosity of the anode active material layer 2 is 10%, 20%, 30%, 50%, 55%, or the like. On the basis of the above embodiment, the pore concentration of the negative electrode active material layer 2 is 5% to 40%, so that the problem that the pore concentration of the negative electrode active material layer 2 is too high, the loss of the negative electrode active material is too much, the energy density of the battery cell is influenced, the problem that the pore concentration of the negative electrode active material layer 2 is too low is avoided, and the metal lithium 4 embedded in the negative electrode active material layer 2 is too little, so that the effect of improving the first effect of the battery cell cannot be achieved.
Note that the porosity of the anode active material layer 2 is the total area of all the pore structures 3 divided by the area of the anode active material layer 2, for example: when the area S1 of the single pore structure 3, the number of pore structures 3 in the negative electrode active material layer 2, and the area of the negative electrode active material layer 2 are n and S2, the porosity of the negative electrode active material layer 2 is (n × S1) ÷ S2.
In order to facilitate embedding of the metal lithium 4 in the pore structure 3 and avoid the problem that the anode active material layer 2 falls off due to overlarge pore diameter, the processability and safety of the anode piece are affected, and on the basis of the embodiment, the pore diameter of the pore structure 3 is not larger than 5 mm. Preferably, the pore structure 3 has a pore diameter in the range of 100 μm to 1.5 mm.
A plurality of hole structures 3 and the perpendicular setting of negative pole mass flow body 1, promptly, a plurality of hole structures 3 and the thickness direction parallel arrangement of negative pole mass flow body 1, from this, can avoid on the one hand to inlay and establish the metal lithium 4 of in hole structures 3 and take off and inlay, get into electrolyte, influence the electrochemical properties of electric core, on the other hand is favorable to storing more electrolyte in hole structures 3 to can make lithium ion to diffusion all around, avoid gathering together.
Pore structure 3 is the blind hole, non-through hole promptly, and pore structure 3's degree of depth is no longer than negative pole active material layer 2's thickness, can avoid pore structure 3 too deeply from this, leads to the local region powder of negative pole active material layer 2 loose, causes the damage to the negative pole piece to and negative pole active material loss is too much, influences the energy density of electric core. On the basis of the embodiment, the depth of the hole structure 3 is not more than half of the thickness of the negative electrode active material layer 2, so that the first effect of the battery cell can be improved, and the influence on the energy density of the battery cell can be avoided. The depth of the pore structure 3 is not more than half the thickness of the negative electrode active material layer 2, and is relative to the thickness of the negative electrode active material layer 2 on the surface of the negative electrode current collector 1 on one side, that is, the depth of the pore structure 3 is not more than half the thickness of the negative electrode active material layer 2 on one side.
Wherein the thickness of the negative electrode active material layer 2 on one surface of the negative electrode current collector 1 is less than 200 μm.
In order to avoid the influence of the inactive solid product on the ion and electron channels of the negative electrode active material layer after lithium is supplemented and to facilitate the storage and transportation of the electrolyte, on the basis of the above embodiment, the embedding depth of the metal lithium 4 is smaller than the depth of the hole structure 3, and the metal lithium 4 is completely embedded in the hole structure 3 and does not protrude out of the hole structure 3.
The negative electrode active material layer 2 includes a negative electrode active material including at least one of graphite, soft carbon, hard carbon, activated carbon, a silicon-based material, a tin-based material, a nitride, and a novel alloy including, but not limited to, a lithium silicon alloy, a lithium tin alloy, or a lithium aluminum alloy.
Metal lithium 4 is an active lithium source for prelithiation, and metal lithium 4 includes lithium powder, lithium strip and lithium block, in order to avoid metal lithium 4 to take off and insert, and enter the electrolyte, influence the electrochemical performance of electric core, on the basis of the above-mentioned embodiment, metal lithium 4 is the lithium block, and the diameter of lithium block is equal to the aperture of pore structure 3, and the lithium block is located the one side of keeping away from the opening of pore structure 3. The lithium block may be a block of lithium having a diameter equal to the diameter of the pore structure 3, or a lithium block formed by compacting lithium powder.
The metal lithium 4 is added into the pore structure 3 of the negative active material layer 2, the pore density of the negative active material layer 2 is in a proper range, the gram capacity of the metal lithium 4 is high, the capacity of the negative active material layer 2 can be improved, active lithium consumed by first irreversible capacity loss is well compensated, and the energy density of the lithium ion battery is further improved; in addition, metal lithium 4 is embedded in the pore structure 3, so that the situation that an inactive solid product is gathered on the surface of the negative electrode to influence the transmission of electrolyte between the negative electrode piece and the diaphragm is avoided, and the cycle performance of the battery cell is favorably improved.
The negative electrode current collector 1 may be provided with a negative electrode active material layer 2 on one surface or both surfaces thereof, and if the negative electrode active material layer 2 is provided on both surfaces of the negative electrode current collector 1, at least one negative electrode active material layer 2 has a pore structure 3, and metal lithium 4 is embedded in the pore structure 3. In order to improve the capacity of the battery and the electrochemical performance of the battery, the two side surfaces of the negative electrode current collector 1 are both provided with the negative electrode active material layers 2, the two negative electrode active material layers 2 are both provided with the pore structures 3, and the metal lithium 4 is embedded in the pore structures 3.
A second aspect of embodiments of the present application provides a method for preparing a negative electrode sheet, which is used for preparing the negative electrode sheet of the first aspect.
Fig. 2 is a process flow chart of the preparation of the negative electrode sheet in the embodiment of the invention, and as shown in fig. 2, the preparation method of the negative electrode sheet includes the following steps:
step S1, providing a negative electrode current collector 1, coating the negative electrode active material slurry on the surface of the negative electrode current collector 1, and forming a negative electrode active material layer 2 after curing;
step S2 of providing a pore structure 3 on the surface of the negative electrode active material layer 2;
step S3, filling the hole structure 3 with lithium metal to obtain a negative electrode sheet.
According to the preparation method of the negative plate, the hole structure is arranged in the negative active material layer, the metal lithium is embedded in the hole structure, after liquid injection, lithium ions pre-embed lithium into the negative active material layer around the hole structure, the gram capacity of the metal lithium is high, active lithium which is lost in first charge and discharge can be compensated, the energy density of the battery cell is improved, an inactive solid product generated by reaction of the metal lithium and an electrolyte shrinks in the hole structure and cannot be gathered on the surface of the negative electrode, a cavity formed by the metal lithium after reaction with the electrolyte is also located in the hole structure, and the negative active material layer cannot be damaged, so that the inactive solid product and the cavity cannot influence the electrolyte transmission between the negative plate and the diaphragm, the DCIR of the surface pre-embedded lithium battery cell and the consumption of the electrolyte are reduced, and the cycle performance of the battery cell is improved; according to the embodiment of the application, the hole structure is arranged in the negative electrode active material layer, the metal lithium is embedded in the hole structure, the electrochemical performance of the battery cell is not influenced while lithium is supplemented, the metal lithium is embedded in the hole structure, the risk that the lithium is separated out to penetrate through the diaphragm to cause short circuit of the battery cell is avoided in the battery cell circulation process, and the safety of the battery cell in the circulation process is effectively improved; in addition, after lithium is pre-embedded, the hole structure in the negative active material layer is filled with the electrolyte, so that the storage and transportation of the electrolyte are facilitated, the liquid retention amount of the electrolyte can be increased, the diffusion distance of lithium ions is reduced, the transmission speed of the lithium ions is increased, and the power performance, the quick charging performance and the cycle performance of a battery cell are facilitated to be improved; the preparation method of the negative plate is simple to operate and is beneficial to realizing industrial production.
The negative current collector 1 is one or more of metal foils such as copper foil, copper alloy foil, nickel alloy foil, titanium foil, and silver foil, and the negative current collector 1 is a copper foil based on the above embodiment.
The negative active material slurry includes a negative active material, a conductive agent, and a binder, wherein the negative active material includes at least one of graphite, soft carbon, hard carbon, activated carbon, a silicon-based material, a tin-based material, a nitride, and a novel alloy. The conductive agent includes at least one of conductive carbon black (SP), Ketjen black, acetylene black, graphite conductive agent (KS-6, KS-15, S-0, SEG-6), carbon fiber (VGCF), Carbon Nanotube (CNT), and graphene, for example, the conductive agent may be conductive carbon black or carbon nanotube. The binder comprises at least one of polyvinylidene fluoride (PVDF for short), polytetrafluoroethylene, styrene butadiene rubber and sodium carboxymethyl cellulose, for example, the binder can be polyvinylidene fluoride or styrene butadiene rubber. The mass percentage of the negative electrode active material, the conductive agent and the binder is 90-97%: 0.5% -5%: 0.5% -5%, preferably, the mass percentage of the negative electrode active material, the conductive agent and the binder is 95%: 3%: 2 percent.
The cathode active material slurry comprises a solid component and a solvent, wherein the solid component is dispersed in the solvent, and the cathode active material slurry is obtained after stirring and mixing are uniform. The negative electrode active material, the conductive agent and the binder are used as solid components of the negative electrode active material slurry, the mass percentage of the solid components in the negative electrode active material slurry is 30-60%, preferably, the mass percentage of the solid components in the negative electrode active material slurry is 60%, and the solvent is water.
After the negative electrode active material layer 2 on the surface of the negative electrode current collector 1 is dried and solidified, holes are formed in the surface of the negative electrode active material layer 2 by means of metal needles or other mechanical punching methods, so that a plurality of hole structures 3 are formed. And injecting the metal lithium 4 into the pore structure 3 in a mechanical injection mode, wherein the depth of the injected metal lithium 4 is smaller than that of the pore structure 3, and the dried and cured metal lithium 4 is completely embedded in the pore structure 3 and does not protrude out of the pore structure 3. The lithium metal 4 may be a lithium block having a diameter equal to the diameter of the pore structure 3, and the lithium metal 4 may also be a lithium block formed by compacting lithium powder.
The third aspect of the embodiment of the present application further provides a battery, including an electric core, where the electric core includes a positive plate, a negative plate, and a diaphragm disposed between the positive plate and the negative plate, the positive plate, the negative plate, and the diaphragm are stacked or wound to form the electric core, the negative plate is the negative plate of the first aspect, the battery further includes an electrolyte and a casing, and the electric core and the electrolyte are packaged in the casing.
According to the battery provided by the embodiment of the application, the hole structure is arranged in the negative electrode active material layer, the metal lithium is embedded in the hole structure, after liquid injection, lithium ions are pre-embedded into the negative electrode active material layer around the hole structure, the gram capacity of the metal lithium is high, active lithium which is lost during first charge and discharge can be compensated, the energy density of the battery cell is improved, an inactive solid product generated by reaction of the metal lithium and an electrolyte is contracted in the hole structure and cannot be gathered on the surface of the negative electrode, and a cavity formed by the metal lithium after reaction with the electrolyte is also located in the hole structure, so that the negative electrode active material layer is not damaged, the inactive solid product and the cavity cannot influence the electrolyte transmission between the negative electrode sheet and the diaphragm, the consumption of DCIR and the electrolyte of the battery cell with the pre-embedded lithium on the surface is favorably reduced, and the cycle performance of the battery cell is improved; according to the embodiment of the application, the hole structure is arranged in the negative electrode active material layer, the metal lithium is embedded in the hole structure, the electrochemical performance of the battery cell is not influenced while lithium is supplemented, the metal lithium is embedded in the hole structure, the risk that the lithium is separated out to penetrate through the diaphragm to cause short circuit of the battery cell is avoided in the battery cell circulation process, and the safety of the battery cell in the circulation process is effectively improved; in addition, after lithium is pre-embedded, the hole structure in the negative active material layer is filled with electrolyte, so that the storage and transportation of the electrolyte are facilitated, the liquid retention capacity of the electrolyte can be improved, the diffusion distance of lithium ions is reduced, the transmission speed of the lithium ions is increased, and the power performance, the quick charging performance and the cycle performance of a battery cell are facilitated to be improved.
After the positive plate, the negative plate and the diaphragm are superposed or wound to form the battery core, the battery core is arranged in the shell, electrolyte is injected into the shell, pre-lithiation is carried out through lithium intercalation reaction between metal lithium and the negative plate, and then packaging and formation are carried out in sequence to obtain the battery.
In the embodiment of this application, positive plate can be the negative pole piece of conventional structure, does not set up the pore structure in the positive active material layer of positive plate promptly, and does not fill metal lithium in the pore structure yet, and positive plate also can adopt the structure the same with negative pole piece, but in order to improve the security of battery to guarantee that the battery has higher energy density, positive plate is the positive plate of conventional structure.
In the battery, the electrolyte may be a liquid electrolyte, the electrolyte may include a lithium salt and a non-aqueous organic solvent, the kind of the electrolyte is not particularly limited as long as the normal transport of metal ions is ensured, and for example, the electrolyte may be LiPF of 1mol/L6And mixing ethylene carbonate, dimethyl carbonate and 1, 2-propylene carbonate according to the volume ratio of 1:1:1 to obtain the non-aqueous organic solvent.
In the battery, the kind of the separator is not particularly limited and may be selected according to actual requirements, and specifically, the separator may be selected from a polyethylene film, a polypropylene film, a polyvinylidene fluoride film, and a multi-layer composite film thereof.
In order to further illustrate the present invention, the following examples are given to further illustrate the present invention. The experimental methods used in the examples of the present invention are all conventional methods unless otherwise specified; materials, reagents and the like used in examples of the present invention are commercially available unless otherwise specified.
Example 1
The present embodiment provides a lithium ion battery, including:
preparing a negative plate: mixing a negative active material graphite Gr + 20% SiO, a binder PVDF and conductive carbon black, and stirring at a high speed to obtain a uniformly dispersed solid component, wherein the mass percent of the graphite Gr + 20% SiO is 95 wt%, the mass percent of the binder PVDF is 2 wt%, and the mass percent of the conductive carbon black is 3 wt%; and uniformly mixing the solid component with water to prepare cathode active slurry, wherein the solid content of the cathode active slurry is 60 wt%. Providing copper foil as a negative current collector, uniformly coating the negative active slurry on the surfaces of both sides of the copper foil, wherein the thickness of a negative active material layer on the surface of one side of the negative current collector is 100 microns, and drying to form a negative active material layer; the surface of the negative electrode active material layer is perforated by machining, a plurality of pore structures are formed in the negative electrode active material layer, the porosity of the negative electrode active material layer is 15%, the diameter of each pore structure is 500 micrometers, and the depth of each pore structure is 30 micrometers.
And adopting a mechanical injection mode to uniformly inject lithium powder into the porous structure, compacting the lithium powder to form a lithium block, wherein the depth of the lithium block is smaller than that of the porous structure, so as to obtain the negative plate, and the lithium block is completely embedded in the porous structure and does not protrude out of the porous structure.
Preparing a positive plate: mixing a ternary nickel-cobalt-manganese NCM serving as a positive electrode active substance, a PVDF (polyvinylidene fluoride) binder and conductive carbon black, stirring at a high speed to obtain a uniformly dispersed mixture, wherein the ternary nickel-cobalt-manganese NCM accounts for 95 wt%, the PVDF binder accounts for 2 wt% and the conductive carbon black accounts for 3 wt%, uniformly mixing the mixture and a solvent by taking N-methyl pyrrolidone as the solvent to prepare positive electrode active slurry, and the solid content of the positive electrode active slurry is 70 wt%. And providing an aluminum foil as a positive current collector, uniformly coating the positive active slurry on the surfaces of two sides of the aluminum foil, and drying, rolling and compacting to obtain the positive plate.
Preparing a battery: punching the positive plate and the negative plate, manufacturing a naked electric core by adopting a Z-shaped lamination, respectively rotating an aluminum tab and a copper nickel-plated tab, clamping the naked electric core by using a glass clamp, wherein the force of the glass clamp is 100MPa/m2And vacuum baking at 85 ℃ for 24 hours, then using the aluminum plastic film as a shell, injecting electrolyte into the aluminum plastic film, wherein the electrolyte adopts 1mol/L lithium hexafluorophosphate electrolyte, and the solvent is ethylene carbonate, dimethyl carbonate and 1,2 propylene carbonate which are mixed according to the volume ratio of 1:1:1 to obtain the non-aqueous organic solvent. After packaging, the battery is formed and aged to obtain a square soft package battery with the length, width and thickness of 60mm multiplied by 40mm multiplied by 5mm, which is marked as C1 and has the design capacity of 5000mAh。
Example 2
This example provides a lithium ion battery, and the preparation process of the lithium ion battery is the same as that in example 1, except that:
when the negative plate is prepared, holes are punched on the surface of the negative active material layer in a machining mode, when a plurality of hole structures are formed, the porosity density of the negative active material layer is 30%, the diameter of each hole structure is 500 micrometers, and the depth of each hole structure is 30 micrometers. The assembled prismatic flexible-packaged battery of this example was designated as C2.
Example 3
This example provides a lithium ion battery, and the preparation process of the lithium ion battery is the same as that in example 1, except that:
when the negative plate is prepared, holes are punched on the surface of the negative active material layer in a machining mode, when a plurality of hole structures are formed, the porosity density of the negative active material layer is 15%, the diameter of each hole structure is 1mm, and the depth of each hole structure is 30 micrometers. The assembled prismatic flexible-packaged battery of this example was designated as C3.
Example 4
This embodiment provides a lithium ion battery, which is prepared in the same manner as in embodiment 1, except that:
when the negative plate is prepared, holes are punched on the surface of the negative active material layer in a mechanical processing mode, when a plurality of hole structures are formed, the porosity density of the negative active material layer is 15%, the diameter of each hole structure is 500 micrometers, and the depth of each hole structure is 50 micrometers. The assembled prismatic flexible-packaged battery of this example was designated as C4.
Comparative example 1
The present comparative example provides a lithium ion battery, which is prepared in the same manner as in example 1, except that:
the negative active material layer of the negative plate is not provided with a hole structure, and the punched lithium pre-embedded negative plate is changed into a conventional non-punched negative plate doped with the same amount of metal lithium. The square flexible packaging battery assembled in this comparative example was designated C5.
Comparative example 2
The present comparative example provides a lithium ion battery, which is prepared in the same manner as in example 1, except that:
the negative electrode active material layer of the negative electrode piece is provided with a hole structure, but no metal lithium is injected into the hole structure, namely, the punched lithium pre-embedded negative electrode piece is changed into a punched negative electrode piece without embedded metal lithium. The square flexible packaging battery assembled in this comparative example was designated C6.
The lithium ion batteries C1 to C6 obtained in examples 1 to 4 and comparative examples 1 to 2 were tested:
test cell dc impedance DCIR: lithium ion batteries C1 to C6 were tested for dc impedance DCIR at 25 ℃, 50% SOC, discharged at 3C for 10s, giving the results shown in table 1.
First effect and energy density of the test cell: the first effect of the lithium ion battery is obtained by measuring the ratio of the first discharge to the first charge of the lithium ion battery, and the energy density of the lithium ion battery is obtained by measuring the ratio of the discharge energy of the lithium ion battery to the weight of the lithium ion battery, and the specific results are shown in table 2.
Testing the cycle performance of the battery: the test lithium ion batteries C1 to C6 were charged at room temperature with a constant current and a constant voltage of 1C to 4.2V, then discharged at 1C to 2.5V, cycled at 100% DOD, and the discharge capacity values for different cycles were recorded to obtain the results shown in table 3, where @ 80% in table 3 represents the number of cycles when the lithium ion battery reached 80% SOC.
TABLE 1
TABLE 2
TABLE 3
It can be seen from table 1 that the larger the contact area between the electrolyte and the pore structure is, the smaller the DCIR is, and under the condition that the pore structures are all arranged in the negative electrode active material layer of the negative electrode sheet, the battery with the metal lithium embedded in the pore structure for pre-lithiation is larger than the DCIR of the battery without the metal lithium embedded in the pore structure, which is mainly because after lithium supplement, the inactive solid product shrinks in the pore structure and cannot be gathered on the surface of the negative electrode and influence is not generated on the DCIR of the battery core, and it can be seen from table 1 that the DCIR of the lithium ion battery with the pre-lithiation method is smaller, and the improvement of the power performance of the lithium ion battery is completely satisfied.
As can be seen from table 2, the first effect of the battery is related to the porosity of the negative active material layer, the higher the porosity, the smaller the pore diameter, the higher the first effect; the energy density of the battery is related to the first effect, the first effect is high, the energy density of the battery is also high, the first effect is low, and the energy density of the battery is also low, wherein the first effect and the energy density of the battery C2 are the highest.
As can be seen from table 3, the higher the first-effect battery, the better the cycle data, the cycle performance of both C2 and C4 batteries can reach more than 2000 times, while the cycle performance of C5 batteries is very poor, only about 200 times, due to the fact that the inactive solid product blocks the passage of electrons and ions in the conventional pre-lithiation manner of the C5 battery on the negative electrode surface.
The results show that the method for pre-lithiation can improve the first effect and the energy density of the battery and ensure that the battery has better electrochemical performance.
Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to be within the scope of the present disclosure.
Claims (10)
1. The negative plate is characterized by comprising a negative current collector and a negative active material layer, wherein the negative active material layer is arranged on at least one side surface of the negative current collector, a hole structure is arranged on the negative active material layer, and metal lithium is embedded in the hole structure.
2. The negative electrode sheet according to claim 1, wherein a plurality of the pore structures are disposed perpendicularly to the negative electrode current collector, and a plurality of the pore structures are uniformly distributed in the negative electrode active material layer.
3. The negative electrode sheet according to claim 1, wherein the pore structure is a blind pore, and the depth of the pore structure is not more than one third of the thickness of the negative electrode active material layer.
4. The negative electrode sheet according to claim 1, wherein the metallic lithium is a lithium block, and the depth of the metallic lithium is smaller than the depth of the pore structure.
5. The negative electrode sheet according to claim 1, wherein the porosity of the negative electrode active material layer is not higher than 60%.
6. The negative electrode sheet according to claim 5, wherein the porosity of the negative electrode active material layer is 5 to 20%.
7. The negative electrode sheet according to claim 1, wherein the pore structure has a pore diameter of not more than 5 mm.
8. Negative electrode sheet according to claim 7, characterized in that the pore structure has a pore diameter of 100 μm to 1.5 mm.
9. A battery, comprising an electric core, wherein the electric core comprises a positive plate, a negative plate and a diaphragm arranged between the positive plate and the negative plate, the positive plate, the negative plate and the diaphragm are stacked or wound to form the electric core, and the negative plate is the negative plate of any one of claims 1 to 8.
10. The preparation method of the negative plate is characterized by comprising the following steps of:
providing a negative current collector, coating negative active material slurry on the surface of the negative current collector, and forming a negative active material layer after curing;
providing a pore structure on the surface of the negative electrode active material layer;
and filling metal lithium into the hole structure to obtain the negative plate.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116314597A (en) * | 2023-05-23 | 2023-06-23 | 珠海冠宇动力电池有限公司 | Battery and electronic equipment |
| WO2024174138A1 (en) * | 2023-02-22 | 2024-08-29 | 宁德时代新能源科技股份有限公司 | Positive electrode sheet, battery, electric apparatus, and electrode sheet preparation method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20190042336A (en) * | 2017-10-16 | 2019-04-24 | 주식회사 엘지화학 | Pre-lithiation method for negative electrode of lithium secondary battery, and lithium metal for pre-lithiation for negative electrode of lithium secondary battery |
| CN109786662A (en) * | 2019-01-18 | 2019-05-21 | 湖北锂诺新能源科技有限公司 | A kind of negative electrode of lithium ion battery mends pole piece and preparation method thereof |
| CN113764753A (en) * | 2021-11-10 | 2021-12-07 | 浙江浙能技术研究院有限公司 | Negative electrode lithium supplementing method and manufacturing method of lithium ion energy storage device |
-
2022
- 2022-02-24 CN CN202210173600.2A patent/CN114583295A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20190042336A (en) * | 2017-10-16 | 2019-04-24 | 주식회사 엘지화학 | Pre-lithiation method for negative electrode of lithium secondary battery, and lithium metal for pre-lithiation for negative electrode of lithium secondary battery |
| CN109786662A (en) * | 2019-01-18 | 2019-05-21 | 湖北锂诺新能源科技有限公司 | A kind of negative electrode of lithium ion battery mends pole piece and preparation method thereof |
| CN113764753A (en) * | 2021-11-10 | 2021-12-07 | 浙江浙能技术研究院有限公司 | Negative electrode lithium supplementing method and manufacturing method of lithium ion energy storage device |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024174138A1 (en) * | 2023-02-22 | 2024-08-29 | 宁德时代新能源科技股份有限公司 | Positive electrode sheet, battery, electric apparatus, and electrode sheet preparation method |
| CN116314597A (en) * | 2023-05-23 | 2023-06-23 | 珠海冠宇动力电池有限公司 | Battery and electronic equipment |
| CN116314597B (en) * | 2023-05-23 | 2023-08-08 | 珠海冠宇动力电池有限公司 | Battery and electronic equipment |
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