CN111370645B - Pole piece and processing method thereof and lithium ion battery - Google Patents

Pole piece and processing method thereof and lithium ion battery Download PDF

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CN111370645B
CN111370645B CN202010459072.8A CN202010459072A CN111370645B CN 111370645 B CN111370645 B CN 111370645B CN 202010459072 A CN202010459072 A CN 202010459072A CN 111370645 B CN111370645 B CN 111370645B
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pole piece
liquid slurry
slurry
pore
lithium
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CN111370645A (en
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何志明
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Beijing Xiaomi Mobile Software Co Ltd
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Beijing Xiaomi Mobile Software Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • 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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  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

The disclosure relates to the technical field of lithium batteries, and particularly provides a pole piece, a processing method of the pole piece and a lithium ion battery. The pole piece processing method comprises the following steps: coating liquid slurry on a current collector; extruding the liquid slurry to form holes, and filling fillers at the hole forming positions; the filler is insoluble in the liquid slurry; and drying and curing the liquid slurry to obtain the pole piece. The method disclosed by the invention does not need post-processing of the dried and solidified pole piece, eliminates the risk of poor battery performance caused by powder falling, and fully utilizes the fluidity of the liquid slurry in the process of pore forming of the liquid slurry to level the liquid around the pore forming, thereby greatly improving the flatness of the surface of the pole piece.

Description

Pole piece and processing method thereof and lithium ion battery
Technical Field
The disclosure relates to the technical field of lithium batteries, in particular to a pole piece, a processing method thereof and a lithium ion battery.
Background
The lithium ion battery is used as an energy storage device capable of being charged and discharged circularly, and is widely applied to the fields of electronic products, new energy automobiles and the like at present. With the increasing demand for energy density of lithium ion batteries, the design of high-coating batteries has become an effective means for increasing energy density, but the high-coating pole pieces are thick and the electrolyte is not easy to permeate, so that the electrolyte cannot remove active substances in the pole pieces, and the capacity and the cycle life of the batteries are seriously influenced.
In the related technology, in order to solve the above problems, a porous pole piece is formed by arranging micro blind holes on the surface of the pole piece, and the porous pole piece is easy to store and soak electrolyte due to high porosity, so that the diffusion distance of lithium ions in the pole piece is greatly reduced, and the performance and the cycle life of the battery are obviously improved. Therefore, research on the porous pole piece is an important direction for improving the energy density of the lithium ion battery.
Disclosure of Invention
In order to realize the processing and preparation of the porous pole piece, the embodiment of the disclosure provides a pole piece, a processing method thereof and a lithium ion battery.
In a first aspect, the present disclosure provides a pole piece processing method, including:
coating liquid slurry on a current collector;
extruding the liquid slurry to form holes, and filling fillers at the hole forming positions; the filler is insoluble in the liquid slurry;
and drying and curing the liquid slurry to obtain the pole piece.
In some embodiments, the filler is a pore former, and the volatilization temperature of the pore former is lower than the drying temperature of the liquid slurry.
In some embodiments, the extruding the pores on the surface of the liquid slurry and filling the filler at the pore-forming positions comprises:
and extruding the surface of the liquid slurry to form a hole by using an injection probe, and injecting a pore-forming agent into the hole-forming position after the surface of the liquid slurry is leveled.
In some embodiments, the pore former comprises at least one of:
ammonium carbonate, ammonium chloride, ammonium bicarbonate, sodium bicarbonate, N-methylpyrrolidone.
In some embodiments, the filler is a solid filler,
the drying and curing of the liquid slurry to obtain the pole piece comprises the following steps:
and drying and curing the liquid slurry, and removing the solid filler to obtain the pole piece.
In some embodiments, the solid filler is a cone structure.
In some embodiments, the liquid slurry comprises at least one of:
lithium cobaltate, lithium manganate, lithium iron phosphate, graphite and lithium titanate.
In some embodiments, the depth of the holes is 1 μm to 200 μm, the diameter of the holes is 1 μm to 100 μm, and the distance between adjacent holes is 10 μm to 500 μm.
In a second aspect, embodiments of the present disclosure provide a pole piece, which is manufactured by the method according to any one of the embodiments of the first aspect.
In a third aspect, an embodiment of the present disclosure provides a lithium ion battery, including the pole piece according to any one of the embodiments of the second aspect.
The pole piece processing method provided by the embodiment of the disclosure comprises the steps of coating liquid slurry on a current collector, extruding and forming holes on the surface of the liquid slurry, filling fillers at the positions of the formed holes, wherein the fillers are insoluble in the liquid slurry, and drying and solidifying the liquid slurry to obtain the pole piece. Through pore-forming on the liquid thick liquids, avoided the pole piece post-processing to the solidification of drying, eliminated the powder problem that falls in the mechanical pore-forming, and then eliminated the risk that the battery performance is bad because the powder that falls leads to. And in the liquid slurry pore-forming, make full use of the mobility of liquid slurry, carry out the levelling to the liquid around the pore-forming, improved the roughness on pole piece surface greatly, improve the performance and the product yield of pole piece. Moreover, the method disclosed by the invention does not need to remove materials and punch holes on the pole piece, so that the loss of active substances is reduced, and the energy density of the battery is improved.
According to the pole piece processing method provided by the embodiment of the disclosure, the filling agent is the pore-forming agent, and the volatilization temperature of the pore-forming agent is lower than the drying temperature of the liquid slurry, so that the pore-forming agent directly volatilizes in the drying and curing process of the liquid slurry, the post-processing process of the pole piece is completely avoided, and the processing flow of the pole piece is greatly simplified. And the injection probe is utilized to extrude the hole on the surface of the liquid slurry, after the surface of the liquid slurry is leveled, the pore-forming agent is injected, the hole forming and the filling of the pore-forming agent are completed at one time, the processing steps are further simplified, and the processing efficiency is improved.
According to the pole piece processing method provided by the embodiment of the disclosure, the filler is a solid filler, and after the liquid slurry is dried and solidified, the solid filler is removed, so that the porous pole piece is obtained. Due to the action of the solid filler, the shape of the formed hole is more complete and uniform, and the performance of the pole piece is improved. And the solid filler is cone structure, and the filler of cone is when getting rid of, and is littleer to the influence on pole piece surface, has avoided getting rid of the risk that the in-process falls powder, improves the yields of pole piece.
According to the pole piece processing method provided by the embodiment of the disclosure, the depth of the holes is 1-200 μm, the aperture is 1-100 μm, and the distance between adjacent holes is 10-500 μm. The performance of the pole piece is not obviously improved due to the fact that the depth of the formed hole is too small, the aperture is too small, and the porosity is too large; and the depth of the formed hole is too large, the aperture is too large, and the porosity is too small, so that the original structure of the pole piece can be damaged, and the performance of the battery is also influenced. Therefore, the processing method of the embodiment reasonably distributes the pore-forming of the pole piece and improves the performance of the pole piece.
The pole piece provided by the embodiment of the disclosure is manufactured by the method of the embodiment, and the surface of the pole piece is formed with a plurality of holes, so that the diffusion distance of lithium ions is reduced, the mass transfer resistance of the lithium ions is effectively reduced, and the performance and the cycle life of the battery are effectively improved. Moreover, the pole piece of the embodiment of the invention effectively avoids the problem of powder falling, has better surface flatness and further improves the performance of the lithium ion battery.
The lithium ion battery provided by the embodiment of the present disclosure includes the pole piece of the above embodiment, and therefore has all the above beneficial effects, which are not described herein again.
Drawings
In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic view of a hole forming structure of mechanical punching in the related art.
Fig. 2 is a flow chart of a pole piece processing method according to some embodiments of the present disclosure.
Fig. 3a to 3d are schematic diagrams of pole piece processing in some embodiments according to the present disclosure.
Detailed Description
The technical solutions of the present disclosure will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only some embodiments of the present disclosure, but not all embodiments. All other embodiments, which can be derived by one of ordinary skill in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure. In addition, technical features involved in different embodiments of the present disclosure described below may be combined with each other as long as they do not conflict with each other.
The pole piece and the processing method thereof provided by the embodiment of the disclosure are suitable for a lithium ion battery, the lithium ion battery generally comprises a positive pole piece, a negative pole piece, a diaphragm, organic electrolyte and the like, and the pole piece in the embodiment of the disclosure, namely the positive pole piece and the negative pole piece of the lithium ion battery.
The pole piece comprises a current collector and an active material coated on the current collector, wherein the active material can be selected from different materials according to the positive and negative electrodes, for example, the positive electrode material can be lithium cobaltate LiCoO2Lithium manganate LiMn2O4, lithium iron phosphate LiFePO4 and the like; the negative electrode material can be graphite and lithium titanate Li2TiO3And the like.
In the related art, the porous pole piece is generally processed by laser or mechanical drilling. Taking mechanical punching as an example, the processing process of the porous pole piece in the related art comprises the following steps:
1) and coating the liquid slurry on the current collector. The liquid paste refers to an electrode active material such as the positive and negative electrode materials described above.
2) And drying and solidifying the liquid slurry to obtain the pole piece without holes. The drying temperature is generally 100-150 ℃.
3) And (4) forming blind holes on the surface of the solidified pole piece by using a metal needle, for example, and finally obtaining the porous pole piece.
Laser drilling is similar.
However, in practical use, the pole piece processing method in the related art is found to have low yield and poor performance. The inventor of the present invention finds, through research and comparison, that the reason is that in the punching process of the pole piece, a large amount of powder falling is generated due to material removal on the surface, and although most of the powder falling can be removed in the subsequent treatment process, the powder falling is difficult to completely remove due to the small size of the blind hole and the large number of holes on the surface of the pole piece. The powder falling of the pole piece in the subsequent process can greatly influence the performance of the battery.
In addition, after further research, the inventors found that the pole piece processed in the related art has poor surface flatness, which results in uneven energy density and also results in reduced battery performance. As shown in fig. 1, when the pole piece is punched, the metal impacts the surface of the pole piece to remove the material, and the material is extruded at the opening of the hole under the impact force due to the internal stress on the surface of the pole piece, so as to form a protruding structure 900. The protruding structures 900 can be seen protruding out of the surface of the pole piece, so that the surface of the pole piece is uneven, the yield of the pole piece is reduced, and the electrical performance of the lithium battery is also affected. In the related art, if the influence of the protruding structures is to be eliminated, the protruding structures need to be ground, which is equivalent to adding post-processing operation, so that the processing technology is more complicated, and more powder is also brought.
Based on the above-mentioned drawbacks in the related art, in a first aspect, the embodiments of the present disclosure provide a pole piece processing method, and some embodiments of the method of the present disclosure are shown in fig. 2.
As shown in fig. 2, in some embodiments, the pole piece processing method of the present disclosure comprises:
s201, coating the liquid slurry on a current collector.
Specifically, the liquid slurry refers to an electrode active material having fluidity, and the liquid slurry is uniformly coated on the current collector, and the coating thickness can be coated according to specific requirements.
In one example, the pole piece is exemplified by a positive pole piece, and the liquid slurry can be, for example, LiCoO2LiMn2O4, LiFePO4, and the like.
In another example, the electrode sheet is a negative electrode sheet, and the liquid slurry may be, for example, graphite or Li2TiO3And the like.
This step is the same as in the related art, and a specific coating manner can be realized by those skilled in the art with the support of the related art, which is not described in detail in this disclosure.
And S202, extruding the liquid slurry to form holes, and filling fillers at the hole forming positions.
Specifically, since the liquid slurry has fluidity, the liquid can be discharged by a small pressing force on the surface of the slurry, and a blind via structure is formed.
In one example, a metal probe may be used, and the probe is inserted into the slurry, thereby discharging the slurry to form a hole site.
Similarly, because the slurry is flowable, if the probe is removed directly from the slurry, the slurry will quickly level. Therefore, in order to make the surface of the slurry have the hole sites, after the slurry is extruded to form the holes, the hole sites are filled with fillers, so that the surface of the slurry maintains the shape of the hole sites.
In one example, the well sites may be filled with a filler such as a pore former, e.g., a liquid solution, so that the slurry remains well site shaped at all times due to the action of the pore former even if the probes are detached from the well sites.
In another example, the filler may be a solid filler, for example, a metal probe is used, that is, the probe is always located in the hole site for keeping the hole site formed after the liquid slurry is discharged to form the hole site.
It is worth mentioning that the holes holding the liquid slurry are shaped by the filler, so that for the selection of the filler, two conditions should be ensured: firstly, the filler cannot react with the slurry; secondly, the filler is dissolved in the slurry differently. One skilled in the art will appreciate that any material that meets these requirements can be used as a filler in the present disclosure, and thus the present disclosure is not limited thereto.
And S203, drying and solidifying the liquid slurry to obtain the pole piece.
Specifically, after the pole piece including the hole is obtained in step S202, the liquid slurry and the filler are sent to a drying device together for drying. After drying, the way of obtaining the pole piece is slightly different according to different selected fillers. For example:
in one example, considering that the drying temperature of the liquid slurry is generally 100 ℃ to 150 ℃, the filler can be selected to be pore-forming agent with a volatilization temperature lower than the temperature, such as ammonium chloride NH4Cl, ammonium bicarbonate NH4HCO3Sodium bicarbonate NaHCO3And N-methylpyrrolidone (NMP) solutions. The evaporation point of the solutions is lower than the drying temperature of the slurry, so that the pore-forming agent is evaporated along with the slurry in the drying process, and thenDirectly form a porous pole piece.
In another example, the filler may be selected from solid fillers, such as metal probes, so that after the slurry is dried and cured, the porous pole piece is obtained by removing the probes.
Of course, those skilled in the art should understand that the present disclosure is not limited to the above-described examples, and those skilled in the art may also implement any other suitable implementation on the basis of the present disclosure, and the present disclosure is not enumerated here.
According to the above, the inventive concept of the embodiment of the present disclosure is different from the method of punching the cured pole piece in the related art, the hole is formed in the liquid slurry, the shape of the hole is maintained by the filler, and then the slurry is dried and cured to obtain the pole piece.
According to the processing method disclosed by the embodiment of the disclosure, post-processing of the solidified pole piece is not needed, so that the influence of powder falling on the electrical property is completely eliminated, and the performance of the pole piece is greatly improved. On the other hand, pore-forming is carried out to liquid thick liquids, because the thick liquids have mobility, consequently can be fast to levelling all around when receiving the extrusion to pole piece surface after the solidification is level and smooth does not have the arch, makes pole piece coating more even, and the electrical property is better. More importantly, the punching in the related art is equivalent to the material removing operation of the active material on the surface of the electrode plate, which is equivalent to the reduction of a part of the active material, while the hole forming in the liquid discharging manner in the present disclosure hardly causes the loss of the active material, and in the case of coating the same amount of the active material, the solution of the present disclosure obviously has more active material, and the energy density of the battery is higher.
One embodiment of the processing method according to the present disclosure is shown in fig. 3a to 3d, and the process of the processing method of the present disclosure is described in detail below with reference to fig. 3a to 3 d.
Referring to fig. 3a, a liquid slurry 200 is first coated on the surface of the current collector 100 to a corresponding thickness. Taking the positive electrode sheet as an example, the liquid slurry 200 may be, for example, LiCoO2Which is uniformly coated on the current collector 100 with a uniform thickness, and the liquid slurry 200 has a certain thicknessAnd (3) fluidity.
Referring to fig. 3b, in the present embodiment, a hole is pressed on the surface of the liquid slurry 200 using an injection probe 300. Specifically, the injection probe 300 is a cone structure, which facilitates the discharge of slurry surface tension and reduces the damage to the slurry state. The injection probe 300 is a hollow structure, a penetrating injection pipe 310 is provided at the center thereof, and a pore-forming agent enters the pore-forming position through the injection pipe 310. As shown in the states (1) to (3) in the drawing, the injection probe 300 is extended downward into the liquid slurry 200, and the liquid on the surface of the slurry 200 is discharged to form a hole. After the liquid on the surface of the slurry 200 is leveled to the periphery, the injection probe 300 is pulled out upwards, and meanwhile, the pore-forming agent 400 is injected into the pore-forming position through the injection pipeline 310, and the pore-forming agent 400 fills the pore position.
Referring to fig. 3c, the step 3b is repeated several times, so that a plurality of structures filled with the pore-forming agent 400 are formed on the surface of the liquid slurry 200.
Referring to FIG. 3d, in the present embodiment, the pore former 400 is selected from, for example, NH4HCO3Solution, NH4HCO3Is extremely easy to volatilize, so when the pole piece is dried, the drying temperature is generally 100-150 ℃, and NH is solidified along with the drying of the slurry 2004HCO3The solution is volatilized, and a plurality of holes 500 are formed on the surface of the pole piece, so that the porous pole piece is obtained finally.
As can be seen from the above, in the present embodiment, the processing on the surface of the pole piece only exists in the liquid slurry stage before the drying operation, and there is no post-processing operation on the solidified pole piece, so that the powder dropping effect in the punching process is completely eliminated, and the electrical performance of the pole piece is improved. More importantly, the liquid slurry is utilized to perform pore-forming operation, the liquidity of the liquid slurry is fully utilized, so that the surface of a pole piece after pore-forming is extremely flat, and the protruding structure 900 is not generated. Accordingly, the protruding structure does not need to be ground and processed as in the related art, so that the processing technology is greatly simplified, and the possibility of powder falling is further eliminated.
In addition, in the present embodiment, the hollow injection probe 300 is used to simultaneously perform the hole formation and the injection in one operation, so as to minimize the number of times of processing the surface of the slurry, thereby saving the processing steps and reducing the influence on the surface structure of the slurry.
It will be appreciated that other alternative embodiments may be implemented by those skilled in the art on the basis of the embodiments of fig. 3a to 3 d. For example, the injection probe 300 may be any other structure suitable for implementation, and is not limited to the conical shape described above, and probes of different structures may be selected according to the shape of the hole. For another example, the pore-forming and the injection may be performed separately, and not necessarily simultaneously, but considering that the slurry itself has a certain fluidity, the shorter the interval time between the pore-forming and the injection is, the better. For another example, the components of the pore-forming agent are not limited to those shown in the above embodiments, and may be any components that do not react with the slurry and are insoluble in the slurry. There are, of course, many alternative embodiments, and those skilled in the art will appreciate that this disclosure is not enumerated here.
In yet another embodiment, which differs from the embodiment shown in fig. 3a to 3d, the filler is a solid filler, rather than a volatile pore former. For example, as shown in fig. 3b, the probe 300 remains directly in the liquid slurry 200 as a filler, in other words, after passing through the state (2), the probe 300 is not pulled out of the slurry any more, but enters a drying step together with the liquid slurry 200. After drying and curing, the probe 300 is removed to obtain the pole piece with the hole.
It should be noted that, in the present embodiment, during the process of removing the solid filler, there may be a small amount of powder falling phenomenon due to a certain processing operation on the solidified pole piece. However, the present embodiment is still different from the punching operation in the related art, and since the punching operation is a material removing operation, a large amount of powder falling is inevitably generated, and the material removing operation is not performed on the pole piece in the present embodiment, so the powder falling amount is negligible relative to the punching operation. More importantly, in the embodiment, the surface of the pole piece can still be leveled through the fluidity of the liquid slurry, and the surface flatness of the pole piece is improved.
Of course, those skilled in the art will appreciate that other alternative embodiments may be used in addition to the present embodiment. For example, the structure of the solid filler may also be set according to the shape of the target hole, which is not limited by the present disclosure. For another example, the material of the solid filler is not limited to the metal probe, and any other material suitable for implementation may be implemented. This disclosure is not further enumerated here.
In some embodiments, the disclosed method processes the pole piece with a depth of the holes of 1 μm to 200 μm, a hole diameter of 1 μm to 100 μm, and a pitch between adjacent holes of 10 μm to 500 μm.
The blind holes formed in the surface of the pole piece are used for reducing the diffusion distance of lithium ions in the pole piece, so that active substances of the pole piece and electrolyte can be better soaked. If the depth of the formed hole is too small, or the pore diameter is too small, or the porosity is too large, the effect is not obviously improved, and the purpose of opening the hole is lost. And if the depth of the formed hole is too large, or the aperture is too large, or the porosity is too small, the originally required pole piece structure can be damaged due to the effect of liquid drainage, so that the performance of the battery is influenced.
Therefore, a large number of experiments show that the depth of the setting hole is 1-200 μm, the aperture is 1-100 μm, and the distance between adjacent holes is 10-500 μm, so that the electrolyte can fully react with the active substances in the pole piece, and the pole piece structure cannot be obviously damaged, and better pole piece performance is obtained.
In a second aspect, an embodiment of the present disclosure provides a pole piece, which is manufactured by the processing method described in any one of the embodiments of the first aspect.
Therefore, the pole piece obtained by the embodiment of the disclosure has the advantages that the plurality of holes are formed on the surface of the pole piece, so that the diffusion distance of lithium ions is reduced, the mass transfer resistance of the lithium ions is effectively reduced, and the performance and the cycle life of the battery are improved. Moreover, the pole piece of the embodiment of the invention effectively avoids the problem of powder falling, has better surface flatness and further improves the performance of the lithium ion battery.
In a third aspect, the disclosed embodiments also provide a lithium ion battery, where the battery includes the pole piece in the second aspect, and the pole piece may be used as both a positive pole piece and a negative pole piece of the battery, which is not limited in this disclosure. For the beneficial effects of the lithium ion battery, reference is made to the foregoing description, and details are not repeated here.
It should be understood that the above embodiments are only examples for clearly illustrating the present invention, and are not intended to limit the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the present disclosure may be made without departing from the scope of the present disclosure.

Claims (12)

1. A pole piece processing method is characterized by comprising the following steps:
coating liquid slurry on a current collector; the liquid slurry has fluidity;
discharging slurry on the surface of the liquid slurry to form a hole site by using an injection probe, wherein the injection probe is provided with a hollow injection pipeline;
after the surface of the liquid slurry is leveled, a pore-forming agent is injected into the hole site through the injection pipeline of the injection probe while the injection probe is pulled out; the pore-forming agent is insoluble in the liquid slurry, and the volatilization temperature of the pore-forming agent is lower than the drying temperature of the liquid slurry;
and drying and curing the liquid slurry to obtain the pole piece.
2. The method of claim 1, wherein the pore former comprises at least one of:
ammonium chloride, ammonium bicarbonate, sodium bicarbonate.
3. The method of claim 1, wherein the liquid slurry comprises at least one of:
lithium cobaltate, lithium manganate and lithium iron phosphate.
4. The method of claim 1, wherein the liquid slurry comprises at least one of:
graphite and lithium titanate.
5. The method of claim 1,
the depth of the holes on the pole piece is 1-200 mu m, the aperture is 1-100 mu m, and the distance between adjacent holes is 10-500 mu m.
6. A pole piece processing method is characterized by comprising the following steps:
coating liquid slurry on a current collector; the liquid slurry has fluidity;
discharging the slurry on the surface of the liquid slurry by using an injection probe to form a hole site;
after the surface of the liquid slurry is leveled, drying and solidifying the liquid slurry;
and drying and curing the liquid slurry, and removing the injection probe to obtain the pole piece.
7. The method of claim 6,
the injection probe is of a cone structure.
8. The method of claim 6, wherein the liquid slurry comprises at least one of:
lithium cobaltate, lithium manganate and lithium iron phosphate.
9. The method of claim 6, wherein the liquid slurry comprises at least one of:
graphite and lithium titanate.
10. The method of claim 6,
the depth of the holes on the pole piece is 1-200 mu m, the aperture is 1-100 mu m, and the distance between adjacent holes is 10-500 mu m.
11. A pole piece, wherein the pole piece is made by a method according to any one of claims 1 to 5, or 6 to 10.
12. A lithium ion battery comprising the pole piece of claim 11.
CN202010459072.8A 2020-05-27 2020-05-27 Pole piece and processing method thereof and lithium ion battery Active CN111370645B (en)

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