WO2022001968A1 - 集流体及其制备工艺、极片及其制备工艺及锂电池 - Google Patents

集流体及其制备工艺、极片及其制备工艺及锂电池 Download PDF

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Publication number
WO2022001968A1
WO2022001968A1 PCT/CN2021/102797 CN2021102797W WO2022001968A1 WO 2022001968 A1 WO2022001968 A1 WO 2022001968A1 CN 2021102797 W CN2021102797 W CN 2021102797W WO 2022001968 A1 WO2022001968 A1 WO 2022001968A1
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Prior art keywords
insulating layer
current collector
tab
area
pole piece
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PCT/CN2021/102797
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English (en)
French (fr)
Inventor
张芹
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厦门海辰新能源科技有限公司
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Publication of WO2022001968A1 publication Critical patent/WO2022001968A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/24—Vacuum evaporation
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • 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
    • 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
    • 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
    • H01M4/66—Selection of materials
    • 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

Definitions

  • the present application relates to the technical field of power batteries, in particular to a current collector and its preparation process, a pole piece and its preparation process, and a lithium battery.
  • the present application discloses a current collector and its preparation process, a pole piece and its preparation process, and a lithium battery, so as to improve the technical problem of the battery short circuit caused by the overlapping of the pole piece at the bending point of the pole or the insertion of the pole into the pole piece.
  • the present application discloses a current collector, comprising a sheet-shaped body, the body has a tab welding area, a tab bending area and a coating area arranged in sequence, wherein,
  • At least one surface of the tab bending area has an insulating layer, and the insulating layer is directly formed on the tab bending area by an evaporation method.
  • the density of the insulating layer is 3.5g/cm 3 -3.85g/cm 3 .
  • the composition of the insulating layer is AlO x , where 1 ⁇ x ⁇ 1.5.
  • the thickness of the insulating layer is not greater than 1 ⁇ m.
  • the present application discloses a preparation process of a current collector, the preparation process of the current collector is used to prepare the above-mentioned current collector, and the preparation process of the current collector includes:
  • the insulating layer is formed by vapor deposition in the bending region of the tab by using vapor deposition equipment.
  • a first baffle is arranged between the main body and the evaporation source of the evaporation device, and a plurality of first through holes for steam to pass through are arranged on the first baffle, and the first through holes are The size and shape match the tab bending area.
  • the first baffle plate has a plurality of first hole groups arranged along a preset direction, and each of the first hole groups includes rows of rows along the preset direction.
  • the two first through holes of the cloth, the spacing between the two first through holes in each first hole group is the same as the width of the coating area, and the adjacent two first through holes are the same as the width of the coating area.
  • the distance between the hole groups is the same as the width of the tab pads.
  • the present application discloses a pole piece, comprising a sheet-like body, and the body is provided with a tab welding area, a tab bending area and a coating area coated with an active material in sequence, wherein,
  • At least one surface of the tab bending area and the coating area has an insulating layer, and the insulating layer is directly formed on the surfaces of the tab bending area and the coating area by an evaporation method.
  • the composition of the insulating layer is AlO x , where 1 ⁇ x ⁇ 1.5.
  • the thickness of the insulating layer is not greater than 1 ⁇ m; and/or,
  • the density of the insulating layer is 3.5g/cm 3 -3.85g/cm 3 .
  • the present application discloses a preparation process of a pole piece, the preparation process of the pole piece is used to prepare the pole piece described in any one of claims 8 to 10, and the preparation process of the pole piece includes:
  • the insulating layer is formed by vapor deposition on the bent region of the tab and the coating region coated with the active material by vapor deposition.
  • an evaporation device is used in the bending area of the tab and the coating area coated with the active material.
  • a second baffle is arranged between the main body and the evaporation source of the evaporation device, and a plurality of second through holes for steam to pass through are provided on the second baffle along a preset direction.
  • the size and shape of the second through holes are matched with the area formed by the tab bending area of the pole piece and the coating area.
  • the plurality of second through holes are arranged at equal intervals, and the distance between two adjacent second through holes is the same as the width of the tab welding area same.
  • the present application further discloses a lithium battery, the lithium battery comprising the above current collector; or,
  • the lithium battery includes the above-mentioned pole pieces.
  • the current collector provided by the present application forms an insulating layer in the bending area of the tab by the method of evaporation.
  • the composition of the insulating layer of the present application is clear and single, and it has been proved that it does not It affects the normal operation of the battery system, and can avoid the problems of many components in the coating colloid, uneven coating of the glue and the formation of pores due to solvent volatilization.
  • the insulating layer and the main body have good firmness and are not easy to fall off, which can reduce the probability of short circuit between the bent part of the tab and the tab, and improve the reliability of the battery core.
  • FIG. 1 is a schematic structural diagram of a current collector disclosed in the present application.
  • Fig. 2 is the flow chart of the preparation process of the current collector disclosed in the present application.
  • FIG. 3 is a schematic structural diagram of a first baffle disclosed in the present application.
  • FIG. 4 is a schematic structural diagram of the evaporation equipment disclosed in the present application.
  • FIG. 5 is a schematic structural diagram of another evaporation device disclosed in the present application.
  • Fig. 6 is the flow chart of the preparation process of the pole piece disclosed in the present application.
  • FIG. 7 is a schematic structural diagram of the second baffle disclosed in the present application.
  • Icons 100, body; 10, tab welding area; 20, tab bending area; 30, coating area; 110, first guide roller; 120, second guide roller; 130, cooling main drum; 140, steaming Plating equipment; 141, first baffle plate; 143, first hole group; 145, first through hole; 150, reaction device; 160, second baffle plate; 161, second through hole.
  • the terms “installed”, “arranged”, “provided”, “connected”, “connected” should be construed broadly. For example, it may be a fixed connection, a detachable connection, or a unitary structure; it may be a mechanical connection, or an electrical connection; it may be directly connected, or indirectly connected through an intermediary, or between two devices, elements, or components. internal communication.
  • installed a fixed connection, a detachable connection, or a unitary structure
  • it may be a mechanical connection, or an electrical connection
  • it may be directly connected, or indirectly connected through an intermediary, or between two devices, elements, or components. internal communication.
  • the specific meanings of the above terms in this application can be understood according to specific situations.
  • first means two or more.
  • FIG. 1 is a schematic structural diagram of the current collector disclosed in the present application.
  • a current collector is provided, the current collector includes a sheet-shaped body 100, and the body 100 has a tab welding area 10, a tab bending area 20 and a coating area 30 arranged in sequence, wherein, At least one surface of the tab bending region 20 is provided with an insulating layer (not shown in the figure), and the insulating layer is directly formed on the tab bending region 20 by an evaporation method.
  • evaporation is the abbreviation of vacuum evaporation, which means that under vacuum conditions, a certain heating evaporation method is used to evaporate and vaporize the coating material (or film material), and the particles fly to the substrate (that is, the film material).
  • the process method of the body 100 in the application to form a film by coagulation on the surface. Evaporation has the advantages of simple film formation method, high film purity and compactness, unique film structure and performance.
  • the inventor of the present application has obtained through experimental research that an insulating layer is formed on at least one surface of the tab bending region of the current collector by the method of evaporation, and the insulating layer formed by this method does not have a pore structure caused by the volatilization of the insulating glue solvent,
  • the insulating layer has a higher bulk density and has better insulating effect.
  • the composition of the insulating layer of the current collector of the present application is clear and single, and it has been confirmed that it does not affect the normal operation of the battery system (diaphragm coating layer), and can be Avoid the problems of many components in the coating colloid, uneven coating of the glue and the formation of pores due to solvent volatilization.
  • the thickness of the insulating layer is small, which hardly affects the volume energy density of the cell, and the insulating layer formed by evaporation is formed between the body and the body. It has good firmness and is not easy to fall off, which can reduce the probability of short circuit between the tab bending area 20 and the tab, and improve the reliability of the cell.
  • the body 100 in the embodiment of the present application may be provided in a rectangle, a circle, an ellipse, a square, a polygon, or other special shapes.
  • the sheet-like body 100 in this embodiment may be made of aluminum foil, copper foil, nickel foil or stainless steel.
  • aluminum foil is preferably used to prepare the body 100.
  • Aluminum foil is currently the most important cathode current collector of lithium batteries. It has good electrical conductivity, light weight and low cost, and the passivation layer on its surface can avoid electrolyte during the charging and discharging process. corrosion.
  • the density of the insulating layer in the present application is 3.5g/cm 3 -3.85g/cm 3 , such as 3.5g/cm 3 , 3.6g/cm 3 , 3.6g/cm 3 , 3.7g/cm 3 , or 3.85g/cm 3 .
  • the density of the insulating layer is less than 3.5g/cm 3 , the insulating effect is not good, and it is inconvenient to fit and fix the body 100 together.
  • the density of the insulating layer is greater than 3.85 g/cm 3 , it is difficult to process and form such a compact shape. the insulating layer.
  • the composition of the insulating layer is AlO x , where 1 ⁇ x ⁇ 1.5.
  • the aluminum material is evaporated, in the process of evaporation, the aluminum vapor is oxidized to form an oxygen-deficient oxide layer on the surface of the main body 100, and the surface of the oxide layer is matured to form aluminum oxide to obtain an insulating layer with a two-layer structure.
  • the structure enables the insulating layer to have better insulating properties.
  • the insulating layer obtained by the reactive evaporation method is grown in a vacuum environment, is firmly embedded on the current collector, can form a whole with the underlying material of the main body 100, is stable and reliable, and has a long service life.
  • the thickness of the insulating layer is not greater than 1 ⁇ m, for example, 0.1 ⁇ m, 0.2 ⁇ m, 0.3 ⁇ m, 0.4 ⁇ m, 0.5 ⁇ m, 0.6 ⁇ m, 0.7 ⁇ m, 0.8 ⁇ m, 0.9 ⁇ m or 1 ⁇ m. If the thickness of the insulating layer is greater than 1 ⁇ m, it is inconvenient for the current collector to bend in the tab bending region 20 after the insulating layer is compared. That is to say, in this embodiment, by making the thickness of the insulating layer not greater than 1 ⁇ m, that is, the thickness of the insulating layer is relatively thin, it is easy for the current collector to be bent later.
  • the thickness of the insulating layer formed by coating is about 2 ⁇ m-10 ⁇ m, and a thinner insulating layer cannot be formed.
  • FIG. 2 is a flow chart of the current collector preparation process disclosed in the present application
  • FIG. 3 is a schematic structural diagram of the first baffle plate disclosed in the present application
  • FIG. 4 is the structure of the evaporation equipment disclosed in the present application.
  • Schematic diagram FIG. 5 is a schematic structural diagram of another vapor deposition apparatus disclosed in this application.
  • the embodiment of the present application discloses a preparation process of a current collector, and the preparation process of the current collector is used to prepare the current collector in the first embodiment.
  • the preparation process of the current collector in the embodiment of the present application includes the following steps:
  • Step 101 preparing a sheet-like body 100 , and making the body 100 form the tab welding area 10 , the tab bending area 20 and the coating area 30 arranged in sequence.
  • aluminum foil, copper foil, nickel foil or stainless steel material, etc. can be used to prepare the body 100 formed into a sheet.
  • aluminum foil is preferably used to prepare the body 100.
  • Aluminum foil is currently the most important cathode current collector of lithium batteries. It has good electrical conductivity, light weight and low cost, and the passivation layer on its surface can avoid electrolyte during the charging and discharging process. corrosion.
  • the body 100 can be made into a rectangle, a circle, an ellipse, a square, a polygon, or other special shapes according to actual design and usage requirements.
  • Step 102 a first baffle 141 is arranged between the main body 100 and the evaporation source of the evaporation device 140 , the first baffle 141 is provided with a plurality of first through holes 145 for steam to pass through, and the first through holes 145 is sized and shaped to match the tab bending region 20 .
  • the current evaporation process is to coat the entire surface of one film surface. Only the capacitor film is coated on a specific area of the film surface, but the corresponding metal layer is plated, and the coating of the non-conductive insulating layer in a specific area is not involved.
  • the current evaporation equipment 140 also does not have the structure and function of coating a specific area of the film surface.
  • the inventor of the present application has improved the structure of the first baffle 141.
  • the first baffle 141 is provided with a plurality of first through holes 145 for steam to pass through.
  • the size and shape of the plurality of first through holes are related to the current collectors.
  • the steam passes through the first through holes 145 to form an insulating layer on the surface of the tab bending region 20 of the current collector to obtain a current collector with an insulating layer.
  • the evaporation method in this application can be magnetron sputtering, resistive evaporation coating, IH crucible evaporation coating or electron beam thermal evaporation coating, etc.
  • the evaporation equipment 140 used is a general equipment in the technical field, which is not described here. specific introduction.
  • the first baffle 141 has a plurality of first hole groups 143 arranged along a preset direction, each first hole group 143 includes two first through holes 145 arranged along a preset direction, each first hole group 143
  • the distance b between the two first through holes 145 in the hole group 143 is the same as the width of the coating area 30
  • the distance c between the two adjacent first hole groups 143 is the same as the width of the tab welding area 10 .
  • the size and shape of the through hole 145 are matched with the size of the tab bending region 20 , wherein the dimension a of the first through hole 145 along the preset direction is the same as the width of the tab bending region 20 , so that the vapor deposition region is the same as the electrode bending region 20 .
  • the ear bend area 20 is matched.
  • the plate body of the first baffle plate 141 in the present application is a common baffle plate in the evaporation equipment 140 , and the structure thereof is not limited in the present application.
  • Step 103 forming an insulating layer by vapor deposition on the tab bending region 20 by using the vapor deposition device 140 .
  • the vapor deposition device 140 is used to cooperate with the guide roller group, the current collector is arranged in the guide roller group and moves with the rotation of the guide roller, and the vapor deposition device 140 vaporizes the current collector.
  • the guide roller group includes structures such as guide rollers, a cooling main drum 130 and the like, and the specific structure of the guide roller group is not limited in the present application.
  • the vacuum evaporation equipment 140 When the current collector is the positive electrode current collector, the vacuum evaporation equipment 140 is used, the metal material such as aluminum is filled in the evaporation equipment 140, and the positive electrode current collector passes through the first guide roller 110, the cooling main drum 130 and the cooling drum 130 at a certain speed in sequence.
  • a first baffle 141 and a reaction device 150 are arranged in the positive electrode current collector and the vapor deposition equipment 140 .
  • the evaporation device 140 vaporizes the electrode piece, and the electrode of the positive electrode current collector is
  • the ear bending region 20 forms a metal layer, and the reaction device 150 delivers a gaseous reactant, such as oxygen, to the metal layer, and the metal layer reacts with the oxygen to form a metal oxide layer, that is, an insulating layer.
  • the vacuum evaporation equipment 140 is used, and the evaporation equipment 140 is filled with non-metallic materials, such as alumina or titanium oxide, and the negative electrode current collector is sequentially passed through the first guide roller 110 at a certain speed. , the main drum 130 and the second guide roller 120 are cooled, and a first baffle plate 141 is set in the negative electrode current collector and the vapor deposition device 140 .
  • the vapor deposition device 140 vaporizes the pole piece to form a non-metallic layer, ie, an insulating layer, on the tab bending region 20 of the negative electrode current collector.
  • the current evaporation process is to coat the entire surface of one film surface. Only the capacitor film is coated on a specific area of the film surface, but the corresponding metal layer is plated, and the coating of the non-conductive insulating layer in a specific area is not involved.
  • the current vapor deposition device also does not have the structure and function of coating a specific area of the film surface.
  • the current collector preparation process provided by the present application can perform vapor deposition in a specific area. After the current collector provided in the present application is obtained, an active material is coated on the coating area 30 to obtain a pole piece. After the pole piece is connected with the tab, the tab bending area 20 has an insulating layer, which can reduce the probability that the tab bending area 20 overlaps the pole piece or the tab is inserted into the pole piece, and reduces the accident rate.
  • the positive electrode current collector and its preparation process include: using vacuum evaporation equipment, and filling the evaporation device with aluminum wires.
  • the positive electrode current collector is sequentially passed through the guide roller, the cooling main drum and the guide roller at a certain speed, and a first baffle plate and a reaction device are arranged in the positive electrode current collector and the evaporation device.
  • the evaporation device evaporates the pole piece.
  • the aluminum vapor is oxidized
  • an oxygen-deficient oxide layer is formed on the surface of the pole piece, and the surface of the oxide layer is matured to form an AlOx layer, that is, an insulating layer.
  • the thickness of the insulating layer was 1 ⁇ m by controlling the movement speed and evaporation amount of the positive electrode current collector. After the insulating layer is obtained, the insulating layer is oxidized to ensure that the oxide layer on the surface is matured.
  • the description of the negative electrode current collector and its preparation process is as follows: the negative electrode current collector and its preparation process include: using vacuum evaporation equipment, and filling the evaporation device with alumina material.
  • the negative electrode current collector is sequentially passed through the guide roller, the cooling main drum and the guide roller at a certain speed, and a first baffle is set in the negative electrode current collector and the evaporation device.
  • the vapor deposition device vaporizes the pole piece to form an aluminum oxide layer, that is, an insulating layer, on a specific area of the negative electrode current collector.
  • the thickness of the insulating layer was 0.8 ⁇ m by controlling the moving speed and evaporation amount of the negative electrode current collector.
  • This comparative example provides a positive electrode or negative electrode current collector, and insulating glue is coated on the surface of the tab bending area of the positive electrode or negative electrode current collector. After the insulating glue is dried, the thickness of the insulating glue is 5 ⁇ m.
  • a pole piece (not shown in the figure), the pole piece includes a sheet-shaped main body, and the main body is sequentially provided with a tab welding area, a tab bending area and an active The coating area of the substance, wherein at least one surface of the tab bending area and the coating area has an insulating layer, and the insulating layer is directly formed on the surfaces of the tab bending area and the coating area by means of evaporation.
  • the preparation process of the current collector can also be used to form an insulating layer on the surface of the tab bending region of the pole piece to obtain a tab having an insulating layer. Since the coated region of the current collector is not coated with the active material, an insulating layer cannot be formed on the coated region. The pole piece does not have this problem, and an insulating layer can be provided in the coating area without affecting the normal use of the pole piece.
  • an insulating layer is formed by vapor deposition on at least one surface of the tab bending area and the coating area of the pole piece by vapor deposition, and the insulating layer formed by this method does not have a pore structure that occurs by volatilization of the insulating glue solvent.
  • the bulk density of the insulating layer is higher and has better insulating effect.
  • the composition of the insulating layer of the pole piece of the present application is clear and single, and it has been confirmed that it does not affect the normal operation of the battery system (diaphragm coating layer), and can be Avoid the problems of many components in the coating colloid, uneven coating of the glue and the formation of pores due to solvent volatilization.
  • the thickness of the insulating layer is small ( ⁇ 1 ⁇ m), which hardly affects the volume energy density of the cell, and the insulating layer formed by evaporation It has good firmness with the body and is not easy to fall off, which can reduce the probability of short circuit occurring when the tab is inserted into the pole piece, and improve the reliability of the cell.
  • the body in the embodiment of the present application may be provided in a rectangular, circular, elliptical, square, polygonal or other special-shaped shape.
  • the sheet-like body in this embodiment may be made of aluminum foil, copper foil, nickel foil or stainless steel.
  • aluminum foil is preferably used to prepare the body.
  • Aluminum foil is the most important cathode current collector of lithium batteries at present. It has good electrical conductivity, light weight and low cost, and the passivation layer on its surface can avoid the electrolytic solution during the charging and discharging process. corrosion.
  • the density of the insulating layer in the present application is 3.5g/cm 3 -3.85g/cm 3 , such as 3.5g/cm 3 , 3.6g/cm 3 , 3.6g/cm 3 , 3.7g/cm 3 , or 3.85g/cm 3 .
  • the density of the insulating layer is less than 3.5g/cm 3 , its insulating effect is not good, and it is not easy to fit and fix it with the body.
  • the density of the insulating layer is greater than 3.85 g/cm 3 , it is difficult to process such a compact Insulation.
  • the composition of the insulating layer is AlO x , where 1 ⁇ x ⁇ 1.5.
  • aluminum vapor in the process of evaporation, aluminum vapor is oxidized and forms an oxide layer with insufficient oxygen on the surface of the main body, and the surface of the oxide layer is matured to form aluminum oxide to obtain an insulating layer with a two-layer structure.
  • the structure makes the insulating layer have better insulating properties.
  • the insulating layer obtained by the reactive evaporation method is grown in a vacuum environment, is firmly embedded on the current collector, can form a whole with the underlying material of the main body 100, is stable and reliable, and has a long service life.
  • the thickness of the insulating layer is not more than 1 ⁇ m, for example, 0.1 ⁇ m, 0.2 ⁇ m, 0.3 ⁇ m, 0.4 ⁇ m, 0.5 ⁇ m, 0.6 ⁇ m, 0.7 ⁇ m, 0.8 ⁇ m, 0.9 ⁇ m or 1 ⁇ m. If the thickness of the insulating layer is greater than 1 ⁇ m, it is inconvenient for the current collector to bend in the tab bending region 20 after the insulating layer is compared. That is to say, in this embodiment, by making the thickness of the insulating layer not greater than 1 ⁇ m, that is, the thickness of the insulating layer is relatively thin, it is easy for the current collector to be bent later.
  • the thickness of the insulating layer formed by coating is about 2 ⁇ m-10 ⁇ m, and a thinner insulating layer cannot be formed.
  • FIG. 6 is a manufacturing process of the pole piece disclosed in the present application
  • FIG. 7 is a schematic structural diagram of the second baffle plate disclosed in the present application.
  • the preparation process of the pole piece is used to prepare the pole piece in the third embodiment.
  • the preparation process of the pole piece includes the following steps:
  • Step 201 prepare a sheet-like body, and make the body form the tab welding area 10 , the tab bending area and the coating area which are arranged in sequence.
  • aluminum foil, copper foil, nickel foil, or stainless steel material, etc. may be used to prepare the body formed into a sheet shape.
  • aluminum foil is preferably used to prepare the main body.
  • Aluminum foil is the most important cathode current collector of lithium batteries at present. It has good electrical conductivity, light weight and low cost, and the passivation layer on its surface can avoid the electrolytic solution during the charging and discharging process. corrosion.
  • the main body can be made into a rectangle, a circle, an ellipse, a square, a polygon or other special shapes according to the actual design and usage requirements.
  • Step 202 Coating the active material on the coating area.
  • Step 203 A second baffle 160 is arranged between the main body and the evaporation source of the evaporation device.
  • the second baffle 160 is provided with a plurality of second through holes 161 along a preset direction for the steam to pass through.
  • the size and shape of the through hole 161 match the area formed by the tab bending area and the coating area of the pole piece.
  • a second baffle 160 is provided between the pole piece and the evaporation source.
  • the inventor of the present application has improved the structure of the second baffle 160, and the second baffle 160 is provided with a plurality of second through holes for steam to pass through. 161, the size of the plurality of second through holes 161 is matched with the tab bending area and the coating area of the pole piece, so that the steam can pass through the second through holes 161 in the tab bending area and the coating area of the pole piece.
  • An insulating layer is formed on the surface.
  • the second baffle 160 will be described in detail below.
  • the second baffle 160 is provided with a plurality of second through holes 161 along a preset direction for the steam to pass through.
  • the sum of the dimensions of the bending zone 20 and the coating zone 30 is the same.
  • the plurality of second through holes 161 are arranged at equal intervals, and the distance between two adjacent second through holes 161 is the same as the width of the tab pad 10 .
  • the plate body of the second baffle plate 160 in this application is a common baffle plate in evaporation equipment, and this application does not limit its structure.
  • the preparation process of the pole piece provided by the present application can perform coating on a specific area of the pole piece, and coat the insulating material.
  • the preparation process can be combined with the preparation process of the pole piece, so as to simplify the operation and reduce the cost.
  • Step 204 using the evaporation equipment 140 to form an insulating layer by evaporation on the bending area of the tab and the coating area coated with the active material.
  • an evaporation device 140 is used to cooperate with a guide roller set, and the evaporation device 140 is filled with a metal material, such as aluminum.
  • the pole piece is arranged on the guide roller group and moves with the rotation of the guide roll.
  • a second baffle 160 and a reaction device 150 are arranged between the pole piece and the evaporation equipment 140.
  • the reaction device 150 delivers a gaseous reactant, such as oxygen, to the metal layer, and the metal layer reacts with the oxygen to form a metal oxide layer, that is, an insulating layer.
  • the preparation process of the pole piece of the present application includes:
  • Vacuum evaporation equipment is used, aluminum wire is filled in the evaporation device, the pole piece is arranged on the guide roller group and moves with the rotation of the guide roller, and a second baffle plate and a reaction device are arranged between the pole piece and the evaporation device.
  • the evaporation device evaporates the pole piece.
  • the aluminum vapor is oxidized and an oxygen-deficient oxide layer is formed on the surface of the pole piece, and the surface of the oxide layer is matured to form an AlO x layer, that is, an insulating layer.
  • the thickness of the insulating layer was 1 ⁇ m by controlling the movement speed and evaporation amount of the positive electrode current collector.
  • This comparative example provides a pole piece. After the positive or negative pole piece is formed, a layer of insulating tape is attached to the surface of the tab bending area during the cell assembly process, and the thickness of the insulating tape is 6 ⁇ m.
  • the current collectors and pole pieces provided in Examples 1 to 4 and Comparative Examples 1 to 2 were selected to detect the breakdown voltage of the insulation performance and to detect the firmness.
  • the breakdown voltage detection method is GB7125-87, and the detection instrument is an electrode device.
  • the test method of firmness is: take double-sided tape, width 20mm, length 100mm, stick it on the table for use, take the test sample, stick it on the surface of the double-sided tape to cover the double-sided tape, and then cut off the excess sample, Use tapes with different adhesive strengths to test the samples. Generally, tapes with different gradients of 300-100N/m are used for testing, and the adhesive strength level is confirmed when not peeled off.
  • the current collectors and pole pieces provided in Examples 1 to 4 have higher breakdown voltages of insulating properties, indicating that they have better insulating properties.
  • the thickness of the insulating layer of the current collector and the pole piece provided in Examples 1 to 4 is not more than 1 ⁇ m, leaving more bending space for the tabs of the battery cell. It is beneficial to the design of low volume energy density of cells.
  • the current collector and the pole piece provided in Examples 1 to 4 have better firm performance.
  • a lithium battery includes the current collector of the first embodiment, or includes the pole piece of the third embodiment. It can be understood that the lithium battery in this application has the above-mentioned current collector or pole piece. Therefore, the lithium battery in this application has all the technical effects of the above-mentioned pole piece or current collector. The technical effect of the sheet or the current collector has been fully explained, and will not be repeated here.

Abstract

一种集流体及其制备工艺、极片及其制备工艺及锂电池。其中，集流体包括片状本体(100)，片状本体(100)具有依次设置的极耳焊接区(10)、极耳弯折区(20)以及涂覆区(30)，极耳弯折区(20)的至少一个表面具有绝缘层，绝缘层通过蒸镀的方法直接形成在极耳弯折区(20)。

Description

集流体及其制备工艺、极片及其制备工艺及锂电池
优先权信息
本申请请求2020年6月30日向中国国家知识产权局递交的专利申请号为2020106237868的优先权。
技术领域
本申请涉动力电池技术领域，尤其涉及一种集流体及其制备工艺、极片及其制备工艺及锂电池。
背景技术
随着动力电池的不断发展，电动汽车燃烧、爆炸等事故频繁发生。其中，锂电池的燃烧、爆炸问题的原因之一是极耳弯折处插入极片，因此防止极耳折弯处与极片电子导通是解决该问题的手段之一。传统的方法是在极耳和极片之间贴一层绝缘胶，但该方法可靠性有限(绝缘胶在电解液中粘性随电芯存储/使用时间渐渐降低，绝缘胶脱落风险高)，成本较高，也增加了制备工艺的复杂性。
发明内容
本申请公开了一种集流体及其制备工艺、极片及其制备工艺及锂电池，以改善极耳弯折处搭接极片或极耳插入极片内造成电池短路的技术问题。
第一方面，本申请公开了一种集流体，包括片状本体，所述本体具有依次设置的极耳焊接区、极耳弯折区以及涂覆区，其中，
所述极耳弯折区的至少一个表面具有绝缘层，所述绝缘层通过蒸镀的方法直接形成在所述极耳弯折区。
作为一种可选的实施方式，在本申请中，所述绝缘层的密度为3.5g/cm 3-3.85g/cm 3。
作为一种可选的实施方式，在本申请中，所述绝缘层的成分为AlO x，其中，1≤x≤1.5。
作为一种可选的实施方式，在本申请中，所述绝缘层的厚度不大于1μm。
第二方面，本申请公开了一种集流体的制备工艺，所述集流体的制备工艺用于制备上述的集流体，所述集流体的制备工艺包括：
制备片状的所述本体，并使得所述本体形成依次设置的所述极耳焊接区、所述极耳弯折区以及所述涂覆区；
采用蒸镀设备在所述极耳弯折区蒸镀形成所述绝缘层。
作为一种可选的实施方式，在本申请中，在制备所述本体之后，采用蒸镀设备在所述极耳弯折区蒸镀形成所述绝缘层之前：
在所述本体与所述蒸镀设备的蒸发源之间设置第一挡板，所述第一挡板上设置有多个供蒸汽穿过的第一通孔，且所述第一通孔的尺寸及形状与所述极耳弯折区相匹配。
作为一种可选的实施方式，在本申请中，所述第一挡板具有沿预设方向设置的多个第一孔组，每个所述第一孔组包括沿所述预设方向排布的两个所述第一通孔，每个所述第一孔组中的两个所述第一通孔的间距与所述涂覆区的宽度相同，相邻的两个所述第一孔组间的距离与所述极耳焊接区的宽度相同。
第三方面，本申请公开了一种极片，包括片状主体，所述主体上依次设置有极耳焊接区、极耳弯折区以及涂覆有活性物质的涂覆区，其中，
所述极耳弯折区和所述涂覆区的至少一个表面具有绝缘层，所述绝缘层通过蒸镀的方法直接形成在所述极耳弯折区和所述涂覆区的表面。
作为一种可选的实施方式，在本申请中，所述绝缘层的成分为AlO x，其中，1≤x≤1.5。
作为一种可选的实施方式，在本申请中，所述绝缘层的厚度不大于1μm；和/或，
所述绝缘层的密度为3.5g/cm 3-3.85g/cm 3。
第四方面，本申请公开了一种极片的制备工艺，所述极片的制备工艺用于制备权利要求8至10中任一项所述的极片，所述极片的制备工艺包括：
制备片状的所述主体，并使得所述主体形成依次设置的所述极耳焊接区、所述极耳弯折区以及所述涂覆区；
在所述涂覆区涂覆活性物质；
采用蒸镀设备在所述极耳弯折区和涂覆有所述活性物质的所述涂覆区蒸镀形成所述绝缘层。
作为一种可选的实施方式，在本申请中，在所述涂覆区涂覆活性物质之后，采用蒸镀设备在所述极耳弯折区和涂覆有所述活性物质的所述涂覆区蒸镀形成所述绝缘层之前：
在所述主体与所述蒸镀设备的蒸发源之间设置第二挡板，所述第二挡板上沿预设方向设有多个供蒸汽穿过的第二通孔，所述多个第二通孔的尺寸和形状与所述极片的极耳弯折区和所述涂覆区共同形成的区域相匹配。
作为一种可选的实施方式，在本申请中，所述多个第二通孔等间距设置，相邻的两个所述第二通孔之间的距离与所述极耳焊接区的宽度相同。
第五方面，本申请还公开了一种锂电池，所述锂电池包括上述的集流体；或者，
所述锂电池包括上述的极片。
本申请至少具有以下有益效果：
本申请提供的集流体通过蒸镀的方法在极耳弯折区形成绝缘层，相比目前的涂覆形成的绝缘层的结构而言，本申请的绝缘层成分明确且单一，已被证实不影响电池体系正常工作，可避免涂覆胶体中成分较多、胶涂覆不均匀以及溶剂挥发而形成孔隙的问题，该绝缘层厚度小，几乎不影响电芯的体积能量密度，并且蒸镀形成的绝缘层与本体之间牢固性好，不易脱落，能够降低极耳弯折处与极耳接触发生短路的概率，提高电芯可靠性。
附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1是本申请公开的集流体的结构示意图；
图2是本申请公开的集流体的制备工艺的流程图；
图3是本申请公开的第一挡板的结构示意图；
图4是本申请公开的蒸镀设备的结构示意图；
图5是本申请公开的另一种蒸镀设备的结构示意图；
图6是本申请公开的极片的制备工艺的流程图；
图7是本申请公开的第二挡板的结构示意图。
图标：100、本体；10、极耳焊接区；20、极耳弯折区；30、涂覆区；110、第一导辊；120、第二导辊；130、冷却主鼓；140、蒸镀设备；141、第一挡板；143、第一孔组；145、第一通孔；150、反应装置；160、第二挡板；161、第二通孔。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
在本申请中，术语“上”、“下”、“左”、“右”、“前”、“后”、“顶”、“底”、“内”、“外”、“中”、“竖直”、“水平”、“横向”、“纵向”等指示的方位或位置关系为基于附图所示的方位或位置关系。这些术语主要是为了更好地描述本申请及其实施例，并非用于限定所指示的装置、元件或组成部分必须具有特定方位，或以特定方位进行构造和操作。
并且，上述部分术语除了可以用于表示方位或位置关系以外，还可能用于表示其他含义，例如术语“上”在某些情况下也可能用于表示某种依附关系或连接关系。对于本领域普通技术人员而言，可以根据具体情况理解这些术语在本申请中的具体含义。
此外，术语“安装”、“设置”、“设有”、“连接”、“相连”应做广义理解。例如，可以是固定连接，可拆卸连接，或整体式构造；可以是机械连接，或电连接；可以是直接相连，或者是通过中间媒介间接相连，又或者是两个装置、元件或组成部分之间内部的连通。对于本领域普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
此外，术语“第一”、“第二”等主要是用于区分不同的装置、元件或组成部分(具体的种类和构造可能相同也可能不同，并非用于表明或暗示所指示装置、元件或组成部分的相对重要性和数量。除非另有说明，“多个”的含义为两个或两个以上。
以下将结合附图进行详细描述。
实施例一
参见图1所示，图1是本申请公开的集流体的结构示意图。根据本申请的 实施例一，提供了一种集流体，该集流体包括片状本体100，本体100具有依次设置的极耳焊接区10、极耳弯折区20以及涂覆区30，其中，极耳弯折区20的至少一个表面具有绝缘层(图中未示出)，该绝缘层通过蒸镀的方法直接形成在极耳弯折区20。
在本申请中，蒸镀是真空蒸镀的简称，是指在真空条件下，采用一定的加热蒸发方式蒸发镀膜材料(或称膜料)并使之气化，粒子飞至基片(即本申请中的本体100)表面凝聚成膜的工艺方法。蒸镀具有成膜方法简单、薄膜纯度和致密性高、膜结构和性能独特等优点。
本申请发明人通过实验研究得出，采用蒸镀的方法在集流体的极耳弯折区的至少一个表面形成绝缘层，通过该方式形成的绝缘层不存在绝缘胶溶剂挥发出现的孔隙结构，该绝缘层的体密度较高，具有较好的绝缘效果。相比现有技术中采用涂覆方式形成的绝缘层的结构而言，本申请的集流体的绝缘层的成分明确且单一，已被证实不影响电池体系正常工作(隔膜涂覆层)，可避免涂覆胶体中成分较多、胶涂覆不均匀以及溶剂挥发而形成孔隙的问题，该绝缘层厚度小，几乎不影响电芯的体积能量密度，并且蒸镀形成的绝缘层与本体之间牢固性好，不易脱落，能够降低极耳弯折区20与极耳接触发生短路的概率，提高电芯可靠性。
本申请实施例中的本体100可以呈长方形、圆形、椭圆形、方形、多边形或者其他异形形状设置。示例性地，本实施例中的片状的本体100可以采用铝箔、铜箔、镍箔或者不锈钢材料制备而成。本申请中优选采用铝箔来制备本体100，铝箔是目前锂电池最主要的正极集流体，其导电性能好、质量轻、成本低廉，并且在充放电过程中其表面的钝化层可以避免电解液的腐蚀。
进一步地，本申请中的绝缘层的密度为3.5g/cm 3-3.85g/cm 3，例如3.5g/cm 3、3.6g/cm 3、3.6g/cm 3、3.7g/cm 3、或者3.85g/cm 3。当绝缘层的密度小于3.5g/cm 3时，其绝缘效果不好，且不便于与本体100贴合固定在一起，当绝缘层的密度大于3.85g/cm 3，则难于加工形成如此紧致的绝缘层。
在本申请中的一些实施方式中，绝缘层的成分为AlO x，其中，1≤x≤1.5。当蒸镀铝材时，在蒸镀的过程中，铝蒸汽被氧化并在本体100的表面形成欠氧的氧化层，氧化层表面再经过熟化后形成氧化铝，得到两层结构的绝缘层，该结构使得绝缘层具有较好的绝缘性能。同时采用反应蒸镀方法获得的绝缘层是在真空环境中生长形成的，在集流体上嵌入牢固，能够与本体100的底层 材料形成一个整体，稳定可靠，寿命长。
进一步地，绝缘层的厚度不大于1μm，例如0.1μm、0.2μm、0.3μm、0.4μm、0.5μm、0.6μm、0.7μm、0.8μm、0.9μm或者1μm等。如果绝缘层的厚度大于1μm，则绝缘层比较后，不便于集流体在极耳弯折区20进行弯折。也即是说，本实施例中通过使绝缘层的厚度不大于1μm，即绝缘层的厚度较薄，易于集流体进行后期弯折。而涂覆形成的绝缘层厚度在2μm-10μm左右，无法形成较薄的绝缘层。
实施例二
参见图2至5所示，图2是本申请公开的集流体制备工艺的流程图，图3是本申请公开的第一挡板的结构示意图，图4是本申请公开的蒸镀设备的结构示意图，图5是本申请公开的另一种蒸镀设备的结构示意图。具体地，本申请实施例公开了一种集流体的制备工艺，该集流体的制备工艺用于制备实施例一中的集流体。
具体来说，本申请实施例中的集流体的制备工艺包括如下步骤：
步骤101：制备片状的本体100，并使得本体100形成依次设置的极耳焊接区10、极耳弯折区20以及涂覆区30。
在该步骤中，可以采用铝箔、铜箔、镍箔或者不锈钢材料等来制备形成片状的本体100。本申请中优选采用铝箔来制备本体100，铝箔是目前锂电池最主要的正极集流体，其导电性能好、质量轻、成本低廉，并且在充放电过程中其表面的钝化层可以避免电解液的腐蚀。具体地，可以根据实际的设计和使用需求将本体100制备成长方形、圆形、椭圆形、方形、多边形或者其他异形形状。
步骤102：在本体100与蒸镀设备140的蒸发源之间设置第一挡板141，该第一挡板141上设置有多个供蒸汽穿过的第一通孔145，且第一通孔145的尺寸及形状与极耳弯折区20相匹配。目前的蒸镀工艺是在一个膜面的整个表面镀膜，只有电容膜是进行膜面特定区域镀膜，但是其对应镀的是金属层，不涉及特定区域非导电的绝缘层的镀膜。目前的蒸镀设备140也没有对膜面特定区域镀膜的结构及功能。
本申请发明人对第一挡板141的结构进行了改进，第一挡板141上设有多个供蒸汽穿过的第一通孔145，多个第一通孔的尺寸及形状与集流体上的 极耳弯折区相匹配，开启蒸发源时，使得蒸汽穿过第一通孔145在集流体的极耳弯折区20的表面形成绝缘层，得到具有绝缘层的集流体。本申请中的蒸镀方法可以为磁控溅射、电阻式蒸发镀膜、IH坩埚式蒸发镀膜或电子束热蒸发镀膜等，采用的蒸镀设备140为本技术领域的通用设备，此处不做具体的介绍。
进一步地，第一挡板141具有沿预设方向设置的多个第一孔组143，每个第一孔组143包括两个沿预设方向排布的第一通孔145，每个第一孔组143中的两个第一通孔145的间距b与涂覆区30的宽度相同，相邻的两个第一孔组143间的距离c与极耳焊接区10的宽度相同，第一通孔145的尺寸及形状与极耳弯折区20的尺寸相匹配，其中，第一通孔145沿预设方向的尺寸a与极耳弯折区20的宽度相同，使得蒸镀区域与极耳弯折区20相匹配。本申请中的第一挡板141的板体为蒸镀设备140中常见的挡板，本申请对其结构不做限定。
步骤103：采用蒸镀设备140在极耳弯折区20蒸镀形成绝缘层。
本申请采用蒸镀设备140与导辊组配合，集流体设置于导辊组并随导辊的转动而运动，蒸镀设备140对集流体进行蒸镀。其中，导辊组包括导辊、冷却主鼓130等结构，本申请对导辊组的具体结构不做限定。
当集流体为正极集流体时，采用真空蒸镀设备140，在蒸镀设备140中填充金属材料，如铝，将正极集流体以一定的速度依次经过第一导辊110、冷却主鼓130和第二导辊120，在正极集流体与蒸镀设备140中设置第一挡板141和反应装置150。当正极集流体经过蒸镀设备140上方，且极耳弯折区20与第一挡板141的第一通孔145对应时，蒸镀设备140对极片进行蒸镀，在正极集流体的极耳弯折区20形成金属层，反应装置150向金属层输送气态的反应物，如氧气，金属层与氧气反应，形成金属氧化层，即形成绝缘层。
当集流体为负极集流体时，采用真空蒸镀设备140，在蒸镀设备140中填充非金属材料，如氧化铝或氧化钛等，将负极集流体以一定的速度依次经过第一导辊110、冷却主鼓130和第二导辊120，在负极集流体与蒸镀设备140中设置第一挡板141。当负极集流体经过蒸镀设备140上方时，蒸镀设备140对极片进行蒸镀，在负极集流体的极耳弯折区20形成非金属层，即形成绝缘层。
目前的蒸镀工艺是在一个膜面的整个表面镀膜，只有电容膜是进行膜面特定区域镀膜，但是其对应镀的是金属层，不涉及特定区域非导电的绝缘层的镀膜。目前的蒸镀装置也没有对膜面特定区域镀膜的结构及功能。本申请 提供的集流体制备工艺能够在特定区域进行蒸镀。得到本申请提供的集流体后，再在涂覆区30涂覆活性物质得到极片。该极片与极耳连接后，极耳弯折区20具有绝缘层，能够降低极耳弯折区20搭接极片或极耳插入极片内的概率，降低事故发生率。
以制备正集流体为例展开说明正极集流体及其制备工艺如下：正极集流体及其制备工艺包括：采用真空蒸镀设备，在蒸镀装置中填充铝丝。将正极集流体以一定的速度依次经过导辊、冷却主鼓和导辊，在正极集流体与蒸镀装置中设置第一挡板和反应装置。
当正极集流体经过蒸镀装置上方，且极耳弯折区与第一挡板的第一通孔对应时，蒸镀装置对极片进行蒸镀，在蒸镀的过程中，铝蒸汽被氧化并在极片表面形成欠氧的氧化层，氧化层表面再经过熟化后形成AlOx层，即形成绝缘层。通过控制正极集流体的运动速度和蒸镀量，绝缘层的厚度为1μm。在得到绝缘层后，对绝缘层进行氧化，保证表面的氧化层被熟化。
以制备负集流体为例展开说明负极集流体及其制备工艺如下：负极集流体及其制备工艺包括：采用真空蒸镀设备，在蒸镀装置中填充氧化铝材料。将负极集流体以一定的速度依次经过导辊、冷却主鼓和导辊，在负极集流体与蒸镀装置中设置第一挡板。
当负极集流体经过蒸镀装置上方时，蒸镀装置对极片进行蒸镀，在负极集流体的特定区域形成氧化铝层，即形成绝缘层。通过控制负极集流体的运动速度和蒸镀量，绝缘层的厚度为0.8μm。
对比例一
本对比例提供一种正极或负极集流体，在该正极或负极集流体的极耳弯折区表面涂布绝缘胶，待绝缘胶干后，绝缘胶的厚度为5μm。
实施例三
根据本申请的实施例三，提供了一种极片(图中未示出)，该极片包括片状主体，主体上依次设置有极耳焊接区、极耳弯折区以及涂覆有活性物质的涂覆区，其中，极耳弯折区和涂覆区的至少一个表面具有绝缘层，绝缘层通过蒸镀的方法直接形成在极耳弯折区和涂覆区的表面。需要说明的是，本申请也可以采用集流体的制备工艺在极片的极耳弯折区表面形成绝缘层以得到具有绝缘层的极耳。由于集流体的涂覆区未涂覆活性物质，因此不能在涂 覆区形成绝缘层。极片则不存在该问题，可以在涂覆区设置绝缘层而不影响极片的正常使用。
对应地，采用蒸镀的方法在极片的极耳弯折区和涂覆区的至少一个表面蒸镀形成绝缘层，通过该方式形成的绝缘层不存在绝缘胶溶剂挥发出现的孔隙结构，该绝缘层的体密度较高，具有较好的绝缘效果。相比现有技术中采用涂覆方式形成的绝缘层的结构而言，本申请的极片的绝缘层的成分明确且单一，已被证实不影响电池体系正常工作(隔膜涂覆层)，可避免涂覆胶体中成分较多、胶涂覆不均匀以及溶剂挥发而形成孔隙的问题，该绝缘层厚度小(≤1μm)，几乎不影响电芯的体积能量密度，并且蒸镀形成的绝缘层与本体之间牢固性好，不易脱落，能够降低极耳插入极片内发生短路的概率，提高电芯可靠性。
同样地，本申请实施例中的本体可以呈长方形、圆形、椭圆形、方形、多边形或者其他异形形状设置。示例性地，本实施例中的片状的本体可以采用铝箔、铜箔、镍箔或者不锈钢材料制备而成。本申请中优选采用铝箔来制备本体，铝箔是目前锂电池最主要的正极集流体，其导电性能好、质量轻、成本低廉，并且在充放电过程中其表面的钝化层可以避免电解液的腐蚀。
进一步地，本申请中的绝缘层的密度为3.5g/cm 3-3.85g/cm 3，例如3.5g/cm 3、3.6g/cm 3、3.6g/cm 3、3.7g/cm 3、或者3.85g/cm 3。当绝缘层的密度小于3.5g/cm 3时，其绝缘效果不好，且不便于与本体贴合固定在一起，当绝缘层的密度大于3.85g/cm 3，则难于加工形成如此紧致的绝缘层。
在本申请中的一些实施方式中，绝缘层的成分为AlO x，其中，1≤x≤1.5。当蒸镀铝材时，在蒸镀的过程中，铝蒸汽被氧化并在本体的表面形成欠氧的氧化层，氧化层表面再经过熟化后形成氧化铝，得到两层结构的绝缘层，该结构使得绝缘层具有较好的绝缘性能。同时采用反应蒸镀方法获得的绝缘层是在真空环境中生长形成的，在集流体上嵌入牢固，能够与本体100的底层材料形成一个整体，稳定可靠，寿命长。
进一步地，绝缘层的厚度不大于1μm，例如0.1μm、0.2μm、0.3μm、0.4μm、0.5μm、0.6μm、0.7μm、0.8μm、0.9μm或者1μm等。如果绝缘层的厚度大于1μm，则绝缘层比较后，不便于集流体在极耳弯折区20进行弯折。也即是说，本实施例中通过使绝缘层的厚度不大于1μm，即绝缘层的厚度较薄，易于集流体进行后期弯折。而涂覆形成的绝缘层厚度在2μm-10μm左右， 无法形成较薄的绝缘层。
实施例四
参见图6和图7所示，图6是本申请公开的极片的制备工艺，图7是本申请公开的第二挡板的结构示意图。该极片的制备工艺用于制备实施例三中的极片。该极片的制备工艺包括如下步骤：
步骤201：制备片状的主体，并使得主体形成依次设置的极耳焊接区10、极耳弯折区以及涂覆区。
在该步骤中，可以采用铝箔、铜箔、镍箔或者不锈钢材料等来制备形成片状的主体。本申请中优选采用铝箔来制备主体，铝箔是目前锂电池最主要的正极集流体，其导电性能好、质量轻、成本低廉，并且在充放电过程中其表面的钝化层可以避免电解液的腐蚀。具体地，可以根据实际的设计和使用需求将主体制备成长方形、圆形、椭圆形、方形、多边形或者其他异形形状。
步骤202：在涂覆区涂覆活性物质。
步骤203：在主体与蒸镀设备的蒸发源之间设置第二挡板160，第二挡板160上沿预设方向设有多个供蒸汽穿过的第二通孔161，多个第二通孔161的尺寸和形状与极片的极耳弯折区和涂覆区共同形成的区域相匹配。
在本申请的部分实施例中，在极片与蒸发源之间设置第二挡板160。目前没有能够实现仅针对极片特定区域蒸镀的装置，本申请发明人对第二挡板160的结构进行了改进，第二挡板160上设有多个供蒸汽穿过的第二通孔161，多个第二通孔161的尺寸与极片的极耳弯折区和涂覆区相匹配，使得蒸汽能够穿过第二通孔161在极片的极耳弯折区和涂覆区表面形成绝缘层。
下面对第二挡板160进行详细说明，第二挡板160上沿预设方向设有多个供蒸汽穿过的第二通孔161，第二通孔161的尺寸与极片的极耳弯折区20和涂覆区30的尺寸之和相同。多个第二通孔161等间距设置，相邻的两个第二通孔161之间的距离与极耳焊接区10的宽度相同。本申请中的第二挡板160的板体为蒸镀设备中常见的挡板，本申请对其结构不做限定。
本申请提供的极片的制备工艺能够在极片的特定区域进行镀膜，且镀上绝缘材料。该制备工艺能够与极片的制备工艺结合，简化操作，降低成本。
步骤204：采用蒸镀设备140在极耳弯折区和涂覆有活性物质的涂覆区蒸镀形成绝缘层。
请参见图4和图5，本申请采用蒸镀设备140与导辊组配合，蒸镀设备140中填充金属材料，如铝。极片设置于导辊组并随导辊的转动而运动，极片与蒸镀设备140之间设有第二挡板160和反应装置150，当极片经过蒸镀设备140上方，且极耳弯折区与涂覆区与第二挡板160上的第二通孔161对应时，蒸镀设备140对极片进行蒸镀，在极片的极耳弯折区与涂覆区形成金属层，反应装置150向金属层输送气态的反应物，如氧气，金属层与氧气反应，形成金属氧化层，即形成绝缘层。
也即是说，本申请极片的制备工艺包括：
采用真空蒸镀设备，在蒸镀装置中填充铝丝，极片设置于导辊组并随导辊的转动而运动，极片与蒸镀装置之间设有第二挡板和反应装置。
当极片经过蒸镀装置上方，且极耳弯折区与涂覆区与第二挡板上的第二通孔对应时，蒸镀装置对极片进行蒸镀，在蒸镀的过程中，铝蒸汽被氧化并在极片表面形成欠氧的氧化层，氧化层表面再经过熟化后形成AlO x层，即形成绝缘层。通过控制正极集流体的运动速度和蒸镀量，绝缘层的厚度为1μm。
对比例二
本对比例提供一种极片，在该正极或负极极片形成后，在电芯组装过程中在极耳弯折区表面贴合一层绝缘胶带，绝缘胶带的厚度为6μm。
试验例
选取实施例一至四、对比例一至二提供的集流体和极片，检测绝缘性能的击穿电压，检测牢固度。
击穿电压检测方法为GB7125-87，检测仪器为电极装置。
牢固度的测试方法为：取双面胶带，宽度20mm，长100mm，粘于桌面上备用，取测试样品，将其粘于双面胶表面以覆盖双面胶，然后将多余的样品切去，用不同粘结力的胶带对样品进行剥离测试，一般选用300-100N/m的不同梯度的胶带进行测试，不剥离时确认粘结力等级。
检测结果如下表：
表1检测结果
Figure PCTCN2021102797-appb-000001
Figure PCTCN2021102797-appb-000002
由表1可知，相比于对比例，实施例一至四提供的集流体和极片具有较高的绝缘性能的击穿电压，说明其具有较好的绝缘性能。相比于对比例一和对比例二的绝缘胶厚度，实施例一至四提供的集流体和极片的绝缘层厚度不大于1μm，给电芯留下了更多的极耳弯折空间，有利于电芯低体积能量密度设计。此外，相比对比例，由于小于1um的AlO x与集流体之间结合力优良，实施例一至四提供的集流体和极片具有较好的牢固性能。
实施例五
根据本申请的实施例五，提供了一种锂电池。该锂电池包括实施例一种的集流体，或者包括实施例三中的极片。可以理解的是，本申请中的锂电池具有前文所述的集流体或者极片，因此，本申请中的锂电池具有前文所述的极片或者集流体所有的技术效果，由于前文已经对极片或者集流体的技术效果进行了充分说明，此处不再赘述。
以上对本申请公开的集流体及其制备工艺、极片及其制备工艺及锂电池进行了详细介绍，本文中应用了具体个例对本申请的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本申请的集流体及其制备工艺、极片及其制备工艺及锂电池及其核心思想；同时，对于本领域的一般技术人员，依据本申请的思想，在具体实施方式及应用范围上均会有改变之处，综上，本说明书内容不应理解为对本申请的限制。

Claims (14)

  1. 一种集流体，其特征在于，包括片状本体，所述本体具有依次设置的极耳焊接区、极耳弯折区以及涂覆区，其中，
    所述极耳弯折区的至少一个表面具有绝缘层，所述绝缘层通过蒸镀的方法直接形成在所述极耳弯折区。
  2. 根据权利要求1所述的集流体，其特征在于，所述绝缘层的密度为3.5g/cm 3-3.85g/cm 3。
  3. 根据权利要求1或2所述的集流体，其特征在于，所述绝缘层的成分为AlO x，其中，1≤x≤1.5。
  4. 根据权利要求1或2所述的集流体，其特征在于，所述绝缘层的厚度不大于1μm。
  5. 一种集流体的制备工艺，其特征在于，所述集流体的制备工艺用于制备权利要求1至4中任一项所述的集流体，所述集流体的制备工艺包括：
    制备片状的所述本体，并使得所述本体形成依次设置的所述极耳焊接区、所述极耳弯折区以及所述涂覆区；
    采用蒸镀设备在所述极耳弯折区蒸镀形成所述绝缘层。
  6. 根据权利要求5所述的集流体的制备工艺，其特征在于，在制备所述本体之后，采用蒸镀设备在所述极耳弯折区蒸镀形成所述绝缘层之前：
    在所述本体与所述蒸镀设备的蒸发源之间设置第一挡板，所述第一挡板上设置有多个供蒸汽穿过的第一通孔，且所述第一通孔的尺寸及形状与所述极耳弯折区相匹配。
  7. 根据权利要求6所述的集流体的制备工艺，其特征在于，所述第一挡板具有沿预设方向设置的多个第一孔组，每个所述第一孔组包括沿所述预设方向排布的两个所述第一通孔，每个所述第一孔组中的两个所述第一通孔的间距与所述涂覆区的宽度相同，相邻的两个所述第一孔组间的距离与所述极耳焊接区的宽度相同。
  8. 一种极片，其特征在于，包括片状主体，所述主体上依次设置有极耳焊接区、极耳弯折区以及涂覆有活性物质的涂覆区，其中，
    所述极耳弯折区和所述涂覆区的至少一个表面具有绝缘层，所述绝缘层通过蒸镀的方法直接形成在所述极耳弯折区和所述涂覆区的表面。
  9. 根据权利要求8所述的极片，其特征在于，所述绝缘层的成分为AlO x，其中，1≤x≤1.5。
  10. 根据权利要求8或9所述的极片，其特征在于，所述绝缘层的厚度不大于1μm；和/或，
    所述绝缘层的密度为3.5g/cm 3-3.85g/cm 3。
  11. 一种极片的制备工艺，其特征在于，所述极片的制备工艺用于制备权利要求8至10中任一项所述的极片，所述极片的制备工艺包括：
    制备片状的所述主体，并使得所述主体形成依次设置的所述极耳焊接区、所述极耳弯折区以及所述涂覆区；
    在所述涂覆区涂覆活性物质；
    采用蒸镀设备在所述极耳弯折区和涂覆有所述活性物质的所述涂覆区蒸镀形成所述绝缘层。
  12. 根据权利要求11所述的极片的制备工艺，其特征在于，在所述涂覆区涂覆活性物质之后，采用蒸镀设备在所述极耳弯折区和涂覆有所述活性物质的所述涂覆区蒸镀形成所述绝缘层之前：
    在所述主体与所述蒸镀设备的蒸发源之间设置第二挡板，所述第二挡板上沿预设方向设有多个供蒸汽穿过的第二通孔，所述多个第二通孔的尺寸和形状与所述极片的极耳弯折区和所述涂覆区共同形成的区域相匹配。
  13. 根据权利要求12所述的极片的制备工艺，其特征在于，所述多个第二通孔等间距设置，相邻的两个所述第二通孔之间的距离与所述极耳焊接区的宽度相同。
  14. 一种锂电池，其特征在于，所述锂电池包括1至4中任一项所述的集流体；或者，
    所述锂电池包括权利要求8至10中任一项所述的极片。
PCT/CN2021/102797 2020-06-30 2021-06-28 集流体及其制备工艺、极片及其制备工艺及锂电池 WO2022001968A1 (zh)

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