CN116093245A - Pole piece, battery and method for removing burrs on end face of current collector - Google Patents

Pole piece, battery and method for removing burrs on end face of current collector Download PDF

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Publication number
CN116093245A
CN116093245A CN202310245808.5A CN202310245808A CN116093245A CN 116093245 A CN116093245 A CN 116093245A CN 202310245808 A CN202310245808 A CN 202310245808A CN 116093245 A CN116093245 A CN 116093245A
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Prior art keywords
current collector
pole piece
face
battery
burrs
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CN202310245808.5A
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Chinese (zh)
Inventor
朱复春
付小虎
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Zhuhai Cosmx Battery Co Ltd
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Zhuhai Cosmx Battery Co Ltd
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Priority to CN202310245808.5A priority Critical patent/CN116093245A/en
Publication of CN116093245A publication Critical patent/CN116093245A/en
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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
    • H01M4/0471—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
    • H01M4/04—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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention provides a pole piece, a battery and a method for removing burrs on the end face of a current collector. The first aspect of the invention provides a pole piece, which comprises a current collector and an active material layer positioned on at least one surface of the current collector, wherein sharp-corner-free particles with the particle size of 0-1 mm are attached to the end face of the current collector. According to the invention, burrs on the end face of the current collector are changed into particles without sharp angles, so that the possibility of short circuit and thermal runaway caused by the penetration of the burrs through a diaphragm is eliminated, the self-discharge performance of the battery is improved, and the electrical performance and the safety of the battery are improved; at the same time, the change of the morphology does not affect the existing preparation process and battery performance.

Description

Pole piece, battery and method for removing burrs on end face of current collector
Technical Field
The invention relates to a pole piece, a battery and a method for removing burrs on the end face of a current collector, and relates to the technical field of batteries.
Background
As a device capable of generating electric energy, a battery has been widely used in various fields such as 3C, small power, electric vehicles, energy storage, and the like. However, in case of short circuit, problems such as battery failure, even fire, explosion, etc. are easily generated, causing serious damage, so that the safety problem of the battery largely limits the application and popularization of the battery.
The current collector is used as one of important components of the battery, burrs are formed on the cutting end face in the cutting process, the sharp ends of the burrs easily pierce through the diaphragm to cause short circuit of the battery, the self-discharge performance of the battery is affected, the battery is also disabled in severe cases, thermal runaway occurs, and safety problems such as ignition, explosion and the like occur; therefore, on the basis of ensuring the performance of the battery, burrs at the edge of the current collector are removed, the risks of short circuit and thermal runaway of the battery are reduced, and the safety and the electrical performance of the battery are improved.
Disclosure of Invention
The invention provides a pole piece and a battery, which are used for removing burrs at the edge of a current collector on the basis of ensuring the performance of the battery, eliminating the possibility of battery short circuit and thermal runaway caused by the burrs and improving the electrical performance and the safety of the battery.
The invention also provides a method for removing burrs on the end face of the current collector, which can remove burrs on the edge of the current collector on the basis of ensuring the performance of the battery, eliminate the possibility of battery short circuit and thermal runaway caused by the burrs and improve the electrical performance and the safety of the battery.
The first aspect of the invention provides a pole piece, which comprises a current collector and an active material layer positioned on at least one surface of the current collector, wherein particles with the particle diameter of 0-1 mm and without sharp angles are attached to the end face of the current collector.
As described above, the active material layer includes a binder and a conductive agent;
the active material layer comprises a first region and a second region, wherein the first region is close to the end face of the current collector attached with the particles without sharp angles, and the second region is far away from the end face of the current collector attached with the particles without sharp angles;
the content of binder and/or conductive agent in the first region is less than the content of binder and/or conductive agent in the second region.
As with the pole piece described above, the binder and/or conductive agent in the first region exhibits a molten state morphology.
As described above, in the first region, as the distance between the active material layer and the end face of the current collector to which the particles having no sharp corners are attached decreases, the content of the binder and/or the conductive agent in the active material layer is lower.
As described above, the length of the first region is less than or equal to 5mm.
As described above, in the thickness direction of the pole piece, the particles without sharp angles do not exceed the surface of the active material layer away from the current collector.
The second aspect of the invention provides a method for removing burrs on the end surface of a current collector, comprising the following steps: carrying out heat treatment on the burrs, and enabling the burrs to be heated and melted to obtain a current collector with particles with the particle diameter of 0-1 mm and without sharp angles attached to the end face;
the burrs are formed by cutting the current collector.
The method as described above, the heat treatment comprises heating the burr using a heat source.
In the method described above, the temperature of the heat treatment is equal to or higher than the melting point of the burr.
In the method, the temperature of the end face of the current collector is not lower than 350 ℃ during heat treatment.
A third aspect of the invention provides a battery comprising a pole piece as described in any one of the preceding claims.
According to the invention, burrs on the end face of the current collector are changed into particles without sharp angles, so that the possibility of short circuit and thermal runaway caused by the penetration of the burrs through a diaphragm is eliminated, the self-discharge performance of the battery is improved, and the electrical performance and the safety of the battery are improved; at the same time, the change of the morphology does not affect the existing preparation process and battery performance.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it will be obvious that the drawings in the following description are some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort to a person skilled in the art.
Fig. 1 is a schematic diagram of current collector end face deburring according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a burr treatment on an end surface of a double-sided coating area of a pole piece according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a burr treatment of an end surface of a single-sided coating area of a pole piece according to an embodiment of the present invention;
fig. 4 is a schematic end view of a heat-treated two-sided coated region of a pole piece according to an embodiment of the present invention.
Reference numerals illustrate:
1-a current collector;
2-an active material layer;
3-a heat source;
4-particles without sharp corners.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
As a device capable of generating electric energy, a battery has been widely used in various fields such as 3C, small power, electric vehicles, energy storage, and the like. The current collector is used as one of important components of the battery, burrs can be formed on the cutting end face in the cutting process, the sharp end of the burrs can easily pierce through the diaphragm to cause short circuit of the battery, the self-discharging performance of the battery is affected, the battery can be disabled under severe conditions, thermal runaway occurs, and safety problems such as ignition and explosion occur.
The adhesive paper or the coating is stuck on the end face of the current collector, so that the risk of penetrating through the diaphragm can be relieved to a certain extent, but the requirements on the preparation process are higher, and the energy density of the battery can be influenced, so that the technical problem to be solved in the invention is how to remove burrs at the edge of the current collector, reduce the risk of short circuit and thermal runaway of the battery and improve the safety and the electrical property of the battery on the basis of ensuring the performance of the battery.
Based on the technical problem, a first aspect of the present invention provides a method for removing burrs on an end surface of a current collector, including: carrying out heat treatment on the burrs, and enabling the burrs to be heated and melted to obtain a current collector with particles with the particle diameter of 0-1 mm and without sharp angles attached to the end face;
the burrs are formed by cutting the current collector.
The term "end face" in the present invention refers to the surface formed by slitting the current collector, which is located at both ends of the current collector.
According to the invention, through heat treatment, burrs formed by cutting are changed into round particles without sharp angles, so that the diaphragm is not pierced, and the problems of short circuit and failure of the battery are avoided; further, the particle diameter of the particles without sharp angles is 0-1 mm, and when the particle diameter of the particles without sharp angles is 0mm, the end face of the current collector is free from particle adhesion, and the end face of the current collector is flat.
The "particles" in the present invention may be spherical, ellipsoidal, irregular, etc., and the orientation of the particles may be in any direction, which is not further limited in the present invention.
According to the invention, burrs on the end face of the current collector are changed into particles without sharp angles, so that the possibility of short circuit and thermal runaway caused by the penetration of the burrs through a diaphragm is eliminated, the self-discharge performance of the battery is improved, and the electrical performance and the safety of the battery are improved; at the same time, the change of the morphology does not affect the existing preparation process and battery performance.
In one specific embodiment, the heat treatment includes heating the burrs by using a heat source, wherein in the heating process, the burrs are heated and melted to lose the original form of the burrs, so that the particles which cannot directly penetrate through the separator and have no sharp angles are formed, the particles with larger particle diameters fall off from the end face of the current collector, and the particles with small particle diameters are attached to the end face of the current collector.
The heat treatment may be performed by any heating method, for example, the heat source is one or more of flame, laser and electromagnetic induction.
Further, the flame is a flame formed by any combustible; the laser heating means that a certain induction current is generated on the surface of the burr, so that the temperature of the burr is rapidly increased and reaches a molten state; electromagnetic induction means that an alternating magnetic field generates an induced current in the burr, thereby causing the burr to heat up and reach a molten state.
It can be understood that the temperature generated by the heat source needs to deform the micron-sized foil by heating, i.e. the temperature of the heat treatment should be greater than or equal to the melting point of the burr; further, after the heat treatment, the temperature of the end face of the current collector is not lower than 350 ℃.
Fig. 1 is a schematic diagram of current collector end face burr treatment according to an embodiment of the present invention, as shown in fig. 1, the end face of a current collector 1 is provided with burrs formed by cutting, the burrs are heat treated by using a heat source 3, the heat source 3 is specifically flame, after reaching a certain temperature, the burrs are heated and melted to become particles without sharp angles, part of particles with larger particle size fall off from the current collector end face, and particles with smaller particle size are attached to the current collector end face, so as to obtain particles 4 with the same effect as fig. 4 and attached to the current collector 1 end face without sharp angles.
It will be appreciated that the direction of the burrs on the end face of the current collector may be any direction, and the aspect of the heat source 3 is not limited to the direction shown in fig. 1, and may be any direction as long as the burrs are deformed by being heated and melted.
It can be understood that the current collector provided by the invention can be an anode current collector and/or a cathode current collector, and burrs formed by cutting can be positioned on the end face of one side of the current collector or can be simultaneously positioned on the end faces of two sides of the current collector.
According to the burr treatment method provided by the invention, the heating device is arranged at the downstream of the slitting equipment, so that the existing slitting equipment can be compatible, the existing preparation process is not influenced, and the cost of the heating device required to be additionally arranged is low.
In summary, the invention changes the burrs on the end surface of the current collector into particles without sharp angles, eliminates the possibility of short circuit and thermal runaway caused by the burrs penetrating through the diaphragm, improves the self-discharge performance of the battery, and improves the electrical performance and the safety of the battery; at the same time, the change of the morphology does not affect the existing preparation process and battery performance.
In a second aspect, the present invention provides a pole piece comprising any of the current collectors described above and an active material layer on at least one surface of the current collector, it being understood that the active material layer may be on the upper or lower surface of the current collector, or on both the upper and lower surfaces.
When at least one surface of the current collector is provided with an active material layer, the whole pole piece is generally cut, burrs are formed on the end face of the current collector, and when the burrs are subjected to heat treatment, the active material layer close to the burrs is affected by the heat treatment, so that the binder and/or the conductive agent in the area are in a heated and molten state morphology, and the binder and/or the conductive agent are different from other active material layer areas which are not affected by the heat treatment.
Therefore, the active material layer is divided into a first area and a second area, wherein the first area is close to the end face of the current collector attached with the particles without sharp angles, namely, the area affected by heat and is positioned at the edge of the active material layer, the second area is far away from the end face of the current collector attached with the particles without sharp angles, namely, the area unaffected by heat treatment and is positioned at the middle part of the active material layer, and the content of the binder and/or the conductive agent in the first area is smaller than the content of the binder and/or the conductive agent in the second area.
Further, the binder and/or the conductive agent in the first region exhibits a molten state morphology.
Further, in the first region, as the distance between the active material layer and the end face of the current collector to which the particles having sharp corners or no sharp corners are attached is reduced, the greater the influence of the heat treatment of the active material layer, the lower the content of the binder and/or the conductive agent in the active material layer.
Further, as the heating time is prolonged, the content of the binder and/or the conductive agent in the active material layer is gradually reduced, and in order to avoid the influence of heat treatment on the content of the components in the active material layer, the heat treatment time is not excessively long, and only the burrs are heated and melted and deformed.
Further, too long length of the first region may reduce gram capacity of the active material layer to affect energy density of the battery, and therefore, the length of the first region should not be too high, specifically, the length of the first region is less than or equal to 5mm, and during the heat treatment, the influence of the heat treatment on the active material layer should be avoided as much as possible.
In one embodiment, the particles without sharp corners do not exceed the surface of the active material layer away from the current collector in the thickness direction of the pole piece, i.e. the height of the particles without sharp corners is less than or equal to the total thickness of the pole piece.
In another embodiment, at least part of the particles without sharp corners, in the thickness direction of the pole piece, exceeds the surface of the active material layer remote from the current collector, i.e. the particles without sharp corners can abut against the separator in the battery.
The length of the first region refers to the distance of the first region along the length direction of the pole piece, namely the direction in which the length of the first region is located is the same as the length direction of the pole piece, and the length direction of the pole piece is defined in the conventional art, namely the direction in which the longest edge of the pole piece is located. The thickness direction of the pole piece is also defined conventionally in the art, namely, the direction of the shortest side in the pole piece is the direction of the longest side and the direction of the side between the shortest side are the width direction of the pole piece; the surface of the active material layer facing away from the current collector is referred to as a plane formed along the length and width directions of the pole piece.
The pole piece provided by the invention can be a positive pole piece and/or a negative pole piece, when the pole piece is a positive pole piece, the positive current collector can be a conventional metal foil such as aluminum foil, and the positive active material layer comprises 70-99wt% of positive active material, 0.5-15wt% of conductive agent and 0.5-15wt% of binder according to mass percentage. The positive electrode active material, the conductive agent and the binder are not particularly selected, and may be any conventional materials in the art, and a lithium ion battery is taken as an example, the positive electrode active material includes one or more of Lithium Cobalt Oxide (LCO), nickel cobalt manganese ternary material (NCM), nickel cobalt aluminum ternary material (NCA), nickel cobalt manganese aluminum quaternary material (NCMA), lithium iron phosphate (LFP), lithium Manganese Phosphate (LMP), lithium Vanadium Phosphate (LVP), lithium Manganate (LMO), and lithium-rich manganese group, the conductive agent is selected from one or more of conductive carbon black, acetylene black, ketjen black, conductive graphite, conductive carbon fiber, carbon nanotube, single-walled carbon nanotube, multi-arm carbon nanotube, and carbon fiber, and the binder is selected from one or more of vinylidene fluoride, copolymer of vinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, carboxymethyl cellulose, sodium polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, and styrene-butadiene rubber.
When the pole piece is a negative pole piece, the negative pole current collector can be a copper foil or other conventional metal foil, the negative pole active layer comprises 70-99wt% of negative pole active material, 0.5-15wt% of conductive agent and 0.5-15wt% of binder according to mass percentage, the negative pole active material is selected from one or more of artificial graphite, natural graphite, hard carbon, mesophase carbon microspheres, soft carbon, hard carbon, lithium titanate, silicon carbon and silicon oxide, and the selection of the conductive agent and the binder is the same as that of the positive pole piece.
Fig. 2 is a schematic diagram of a burr treatment of an end surface of a double-sided coating area of a pole piece according to an embodiment of the present invention, and fig. 4 is a schematic diagram of an end surface of a pole piece after heat source treatment according to an embodiment of the present invention, where, as shown in fig. 2 and 4, the pole piece includes a current collector 1 and an active material layer 2 located on the surface of the current collector, the end surface of the current collector 1 after cutting has burrs formed by cutting, the burrs are heat treated by using a heat source 3, after reaching a certain temperature, the burrs are heated and melted to become particles 4 without sharp angles, part of particles with larger particle diameters fall off from the end surface of the current collector, and particles with smaller particle diameters are attached to the end surface of the current collector; at the same time, the edges of the active material layer 2 positioned on the upper and lower surfaces of the current collector are affected by heat treatment, and the internal binder and/or conductive agent have a shape in a heated and molten state, so that the edge area is different from the active material layer area which is not affected by heat treatment in the middle.
Fig. 3 is a schematic diagram of processing burrs on an end face of a single-sided coating area of a current collector according to an embodiment of the present invention, as shown in fig. 3, in the case of a pole piece with an active material layer 2 disposed on only one surface of the current collector, the same heat processing method is used to heat process burrs on the end face of the current collector, so as to achieve the same effect as in fig. 4.
In conclusion, the burrs on the end face of the pole piece are changed into particles without sharp angles, so that the possibility of short circuit and thermal runaway caused by the penetration of the burrs through the diaphragm is eliminated, the self-discharge performance of the battery is improved, and the electrical performance and the safety of the battery are improved; at the same time, the change of the morphology does not affect the existing preparation process and battery performance.
A third aspect of the invention provides a battery comprising any of the current collectors described above or any of the pole pieces described above.
Based on the characteristics of the current collector and the pole piece provided by the invention, the battery comprising the current collector or the pole piece has better electrical property and safety.
In one embodiment, the battery further comprises a separator and an electrolyte.
Illustratively, the electrolyte is a conventional electrolyte known in the art including a lithium salt and a solvent containing ethylene carbonate (abbreviated EC), diethyl carbonate (abbreviated DEC), propylene carbonate (abbreviated PC), fluoroethylene carbonate (abbreviated FEC).
The membrane is illustratively a polypropylene-based material, or a rubberized membrane coated with ceramic on one or both sides on the basis thereof.
The pole piece provided by the invention is described by a specific embodiment.
Example 1
The embodiment provides a pole piece processing method, wherein the pole piece is a positive pole piece and a negative pole piece, and comprises a current collector 1 and active material layers 2 positioned on the upper surface and the lower surface of the current collector, burrs formed by cutting are arranged on the end surface of the current collector 1, the burrs are subjected to heat treatment by using a heat source 3, after a certain temperature is reached, the burrs are heated and melted to become particles 4 without sharp angles, part of particles with larger particle sizes can fall off from the end surface of the current collector, and the particles with smaller particle sizes can be attached to the end surface of the current collector 1; at the same time, the edges of the active material layer 2 positioned on the upper and lower surfaces of the current collector are affected by heat treatment, and the internal binder and/or conductive agent are in a heated and melted form, so that the difference occurs between the edge area and the active material layer area which is not affected by heat treatment in the middle.
Comparative example 1
The electrode sheet provided in this comparative example was not subjected to heat treatment of burrs on the end face of the current collector, otherwise as in example 1.
The electrode sheets provided in example 1 and comparative example 1 were prepared with a separator and an electrolyte to obtain batteries, and the batteries were tested for electrical properties and safety by the following test methods, and the results are shown in table 1.
K value test: the K value (cell decay rate) is defined as the voltage decay value per hour which can be used for representing the self-discharge condition of the battery, the unit is mV/h, the voltage internal resistance at different times is tested, and the K value before and after dropping is tested through the formula K= (OCV 1-OCV 2)/the time interval of two tests.
The safety testing method comprises the following steps: the battery is charged to 4.48V at a constant current and constant voltage of 1.5C, the temperature is cut off to 0.02C, the full-charge battery is placed in an oven at 85 ℃, and when the surface temperature of the battery core reaches 85 ℃, the battery is placed at a constant temperature for 6 hours, and the battery is regarded as passing when no fire or explosion occurs.
Table 1 results of performance test of batteries provided in examples and comparative examples
K value (mV/h) Security (number of passes/total number of tests)
Example 1 0.027 8/10
Comparative example 1 0.042 3/10
According to the data provided in table 1, the burrs on the end face of the current collector are changed into particles without sharp angles, so that the possibility of short circuit and thermal runaway caused by the penetration of the burrs through the diaphragm is eliminated, the self-discharge performance of the battery is improved, and the electrical performance and the safety of the battery are improved; meanwhile, the burr treatment method and the shape change can not influence the existing preparation process and battery performance, and compared with the adhesive tape treatment method, the preparation process is simplified, and the influence of the adhesive tape on the battery energy density is avoided.
In the description of the present invention, the positional or positional relationship indicated by the terms "top", "bottom", "upper", "lower", etc. are based on the positional or positional relationship shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.
In the description of the present invention, a description of the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims (11)

1. The pole piece is characterized by comprising a current collector and an active material layer positioned on at least one surface of the current collector, wherein sharp-corner-free particles with the particle size of 0-1 mm are attached to the end face of the current collector.
2. The pole piece of claim 1, wherein the active material layer comprises a binder and a conductive agent;
the active material layer comprises a first region and a second region, wherein the first region is close to the end face of the current collector attached with the particles without sharp angles, and the second region is far away from the end face of the current collector attached with the particles without sharp angles;
the content of binder and/or conductive agent in the first region is less than the content of binder and/or conductive agent in the second region.
3. A pole piece according to claim 2, characterized in that the binder and/or the conductive agent in the first region exhibits a molten state morphology.
4. A pole piece according to claim 2, characterized in that in the first region the content of binder and/or conductive agent in the active material layer is lower as the distance between the active material layer and the end face of the current collector to which the particles without sharp corners are attached is reduced.
5. A pole piece according to any of claims 2-4, characterized in that the length of the first area is less than or equal to 5mm.
6. A pole piece according to claim 1, characterized in that the particles without sharp corners do not exceed the surface of the active material layer facing away from the current collector in the thickness direction of the pole piece.
7. A method of deburring an end surface of a current collector, comprising: carrying out heat treatment on the burrs, and enabling the burrs to be heated and melted to obtain a current collector with particles with the particle diameter of 0-1 mm and without sharp angles attached to the end face;
the burrs are formed by cutting the current collector.
8. The method of claim 7, wherein the heat treating comprises heating the burr using a heat source.
9. The method according to claim 7 or 8, wherein the temperature of the heat treatment is equal to or higher than the melting point of the burr.
10. A method according to any one of claims 7 to 9, wherein the temperature of the end face of the current collector is not lower than 350 ℃ at the time of heat treatment.
11. A battery comprising a pole piece according to any one of claims 1 to 6.
CN202310245808.5A 2023-03-13 2023-03-13 Pole piece, battery and method for removing burrs on end face of current collector Pending CN116093245A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117219725A (en) * 2023-11-08 2023-12-12 宁德时代新能源科技股份有限公司 Pole piece surface treatment device and process, pole piece production equipment and battery production line

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117219725A (en) * 2023-11-08 2023-12-12 宁德时代新能源科技股份有限公司 Pole piece surface treatment device and process, pole piece production equipment and battery production line

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