WO2025007968A1 - 正极片及其制备方法、电池及其制备方法 - Google Patents

正极片及其制备方法、电池及其制备方法 Download PDF

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Publication number
WO2025007968A1
WO2025007968A1 PCT/CN2024/103973 CN2024103973W WO2025007968A1 WO 2025007968 A1 WO2025007968 A1 WO 2025007968A1 CN 2024103973 W CN2024103973 W CN 2024103973W WO 2025007968 A1 WO2025007968 A1 WO 2025007968A1
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WIPO (PCT)
Prior art keywords
positive electrode
electrode sheet
active material
layer
region
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Ceased
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PCT/CN2024/103973
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English (en)
French (fr)
Inventor
张健
彭冲
方双柱
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Zhuhai Cosmx Battery Co Ltd
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Zhuhai Cosmx Battery Co Ltd
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Publication of WO2025007968A1 publication Critical patent/WO2025007968A1/zh
Anticipated expiration legal-status Critical
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Classifications

    • 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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • 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
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • 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 field of battery technology, and in particular to a positive electrode sheet and a preparation method thereof, a battery and a preparation method thereof.
  • the battery cell with a multi-electrode winding and stacked structure has an ear extending from the pole piece.
  • the current industry practice is to coat an insulating layer on the side of the positive electrode ear to improve safety.
  • Figures 9A and 9B Figure 9A is a top view of the pole piece
  • Figure 9B is a left view of the pole piece along the dotted area of Figure 9A.
  • On the side of the positive electrode ear there is usually an insulating layer of 0.5 to 5 mm near the edge of the pole piece and on the ear.
  • the insulating layer and the active material layer penetrate each other to form a transition zone of a certain width, in which the insulating layer and the active material layer are irregularly distributed. Because the insulating layer does not have the ability to conduct electrons, it is difficult for the active material in the transition zone to participate in the electrochemical reaction, and it is difficult to deintercalate lithium ions. The capacity of this part of the positive electrode active material is lost, reducing the overall capacity of the battery.
  • the present application provides a positive electrode sheet and a preparation method thereof and a battery and a preparation method thereof.
  • the positive electrode sheet is provided with an inactive layer between the current collector and the active material layer, which not only has a protective effect on the current collector, but also can avoid the capacity loss in the transition zone and does not affect the capacity of the active material.
  • the present application provides a positive electrode sheet, which includes a current collector, an inactive layer, an active material layer and a tab; the inactive layer and the active material layer are arranged on at least one side surface of the current collector, and the inactive layer is arranged between the current collector and the active material layer; the active material layer includes an active material, and the inactive layer does not include an active material; along the direction in which the tab extends, the edge of the inactive layer exceeds the edge of the active material layer.
  • the present application eliminates the insulating layer at the edge of the pole piece near the pole ear end, and extends the inactive layer to the position where the insulating layer was originally set, so that there is no transition zone between the inactive layer and the active material layer where the insulating layer and the active material layer penetrate each other, thereby avoiding the capacity loss in the transition zone and not affecting the capacity of the active material.
  • the inactive layer is a coating layer that does not provide a lithium source and has a conductive effect.
  • the vertical distance that the edge of the inactive layer exceeds the edge of the active material layer is 0.5 to 5 mm.
  • the width of the inactive layer is 10.5 to 150 mm, and the width of the active material layer is
  • the present application is not limited thereto, as long as the vertical distance between the edge of the inactive layer and the edge of the active material layer is ensured to be 0.5 to 5 mm.
  • At least one side surface of the current collector includes a first region and a second region, and the tab is arranged at one end of the current collector close to the first region;
  • the inactive layer includes region A and region B, region A is arranged in the first region and part of the tab surface, and region B is arranged in the second region.
  • the thickness of region A is greater than or equal to the thickness of region B. More preferably, the thickness of region A is greater than the thickness of region B.
  • This design can more effectively prevent burrs from being generated, more effectively prevent the positive electrode active material from being completely covered by the negative electrode active material, and improve safety.
  • the thickness of region A is 1 to 50 ⁇ m.
  • the thickness of region A is 5-40 ⁇ m.
  • the thickness of region A is 5 to 20 ⁇ m.
  • the thickness of region B is 0.1 to 20 ⁇ m.
  • the thickness of region B is 1-10 ⁇ m.
  • the thickness of region B is 1 to 5 ⁇ m.
  • the width of region A is d 1
  • the width of region B is d 2
  • the width of the active material layer is d 3
  • d 1 , d 2 , and d 3 satisfy the following relationship:
  • the projection of region A in the length direction is a pentagonal right-angled trapezoid
  • the projection of region B in the length direction is a rectangle.
  • the present application is not limited thereto, and any technical solution that can realize the concept of the present application is within the protection scope of the present application.
  • the inactive layer includes inorganic particles not containing lithium and a binder.
  • the inorganic particles not containing lithium refer to inorganic particles not containing lithium-containing transition metal oxide.
  • the mass percentage of the inorganic particles not containing lithium to the binder is (80wt% to 99wt%): (1wt% to 20wt%).
  • the mass percentage of the inorganic particles not containing lithium to the binder is (90wt% to 99wt%): (1wt% to 10wt%).
  • the inorganic particles not containing lithium include a conductive material and/or an insulating material.
  • the inorganic particles not containing lithium include a conductive material, wherein the conductive material includes a first conductive material and/or an insulating material coated with a second conductive material.
  • the first conductive material includes but is not limited to at least one of ATO (Sb-doped SnO 2 ), FTO (F-doped SnO 2 ), ITO (Sn-doped In 2 O 3 ), and AZO (Al-doped ZnO).
  • ATO Sb-doped SnO 2
  • FTO F-doped SnO 2
  • ITO Sn-doped In 2 O 3
  • AZO Al-doped ZnO
  • the second conductive material includes but is not limited to at least one of carbon black, carbon nanotubes, graphene, ATO, FTO, ITO, and AZO.
  • the inorganic particles not containing lithium only include insulating materials, and the inactive layer further includes a conductive agent.
  • the conductive agent includes but is not limited to at least one of carbon black, carbon nanotubes, graphene, and carbon fiber.
  • the insulating material includes but is not limited to at least one of aluminum oxide, magnesium oxide, titanium oxide, zinc oxide, silicon oxide, boehmite, cobalt oxide, iron phosphate, aluminum phosphate, iron metaphosphate, and aluminum metaphosphate.
  • the adhesive includes but is not limited to at least one of polyvinylidene fluoride (PVDF), acrylic acid-modified PVDF, polyacrylate polymers, polyacrylic acid, polyacrylic salt, polyimide, styrene-butadiene rubber, and styrene-acrylic rubber.
  • PVDF polyvinylidene fluoride
  • acrylic acid-modified PVDF acrylic acid-modified PVDF
  • polyacrylate polymers polyacrylic acid
  • polyacrylic salt polyacrylic salt
  • polyimide polyimide
  • styrene-butadiene rubber styrene-acrylic rubber
  • the inorganic particles not containing lithium are conductive materials, and the mass percentage of the inorganic particles not containing lithium and the binder is (80wt% to 99wt%): (1wt% to 20wt%).
  • the mass percentage of the inorganic particles not containing lithium and the binder is (90wt% to 99wt%): (1wt% to 10wt%).
  • the inorganic particles not containing lithium are insulating materials
  • the inactive layer further comprises a conductive agent
  • the mass percentages of the inorganic particles not containing lithium, the conductive agent and the adhesive are (70wt% to 98wt%): (1wt% to 15wt%): (1wt% to 15wt%).
  • the mass percentages of the inorganic particles not containing lithium, the conductive agent and the adhesive are (80wt% to 98wt%): (1wt% to 10wt%): (1wt% to 10wt%).
  • the second conductive material and the insulating material in the insulating material coated with the second conductive material, can be composed of any proportion, and the coating can be complete or incomplete.
  • the mass ratio of the second conductive material to the insulating material is (1-10): (80-98).
  • the active material layer includes a positive electrode active material, and the positive electrode active material is a transition metal oxide containing lithium;
  • the lithium-containing transition metal oxide includes, but is not limited to, at least one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganese oxide, and lithium-rich manganese-based materials.
  • the active material layer in the positive electrode sheet further includes a conductive agent and/or a binder.
  • the mass percentage of each component in the positive electrode active material layer is: 80wt% to 99.8wt% Positive electrode active material, 0.1wt% to 10wt% of conductive agent, and 0.1wt% to 10wt% of binder.
  • the mass percentage of each component in the positive electrode active material layer is: 90wt% to 99.6wt% of positive electrode active material, 0.2wt% to 5wt% of conductive agent, and 0.2wt% to 5wt% of binder.
  • the present application also provides a method for preparing the above-mentioned positive electrode sheet, comprising the following steps:
  • the active material layer material and the second solvent are mixed to obtain an active material layer slurry, and the active material layer slurry is coated on the inactive layer of the current collector. After drying, rolling, and die-cutting the tabs, a positive electrode sheet is obtained.
  • the inactive layer is prepared by gravure coating.
  • the mesh number of the gravure coating of the preparation area A is 10 to 80 meshes.
  • the mesh number of the gravure coating of the preparation area B is 100 to 150 meshes.
  • the current collector is a material containing aluminum.
  • the aluminum-containing material includes one of aluminum foil, carbon-coated aluminum foil, and aluminum-polymer composite current collector.
  • the present application also provides a battery, which includes a negative electrode sheet, a separator and the positive electrode sheet mentioned above.
  • the vertical distance between the projected edge of the negative electrode sheet on one side of the tab in the length direction and the projected edge of the inactive layer in the positive electrode sheet on one side of the tab in the length direction is d 4
  • the vertical distance between the projected edge of the active material layer in the positive electrode sheet on one side of the tab in the length direction and the projected edge of the inactive layer in the positive electrode sheet on one side of the tab in the length direction is d 5
  • d 4 and d 5 satisfy the following relationship:
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer coated on one side or both sides of the negative electrode current collector, and the negative electrode active material layer includes a negative electrode active material, a conductive agent and a binder.
  • the mass percentage of each component in the negative electrode active material layer is: 80wt% to 99.8wt% of the negative electrode active material, 0.1wt% to 10wt% of the conductive agent, and 0.1wt% to 10wt% of the binder.
  • the mass percentage of each component in the negative electrode active material layer is: 90wt% to 99.6wt% of the negative electrode active material, 0.2wt% to 5wt% of the conductive agent, and 0.2wt% to 5wt% of the binder.
  • the negative electrode active material includes a carbon-based negative electrode material.
  • the carbon-based negative electrode material includes at least one of artificial graphite, natural graphite, mesophase carbon microbeads, hard carbon and soft carbon.
  • the negative electrode active material may further include a silicon-based negative electrode material.
  • the silicon-based negative electrode material is selected from nano-silicon, silicon-oxygen negative electrode material (SiOx, 0 ⁇ x ⁇ 2) or At least one of silicon-carbon negative electrode materials.
  • the mass ratio of the carbon-based negative electrode material to the silicon-based negative electrode material is 10:0 to 1:19.
  • the negative electrode current collector is copper foil.
  • the conductive agent is selected from at least one of conductive carbon black (acetylene black and/or Ketjen black), conductive graphite, conductive carbon fiber, carbon nanotubes, metal powder, and carbon fiber.
  • the binder is selected from at least one of PVDF, sodium carboxymethyl cellulose, styrene-butadiene rubber, polytetrafluoroethylene, and polyethylene oxide.
  • the present application also provides a method for preparing the above-mentioned battery, comprising the following steps:
  • the positive electrode sheet, the separator and the negative electrode sheet are stacked to obtain a stacked core, or the positive electrode sheet, the separator and the negative electrode sheet are stacked and then wound to obtain a wound core, the stacked core or wound core is placed in an outer package, the electrolyte is injected into the outer package, and the battery of the present application is obtained after vacuum packaging, standing and forming.
  • the present invention has the following beneficial effects:
  • the inactive layer in the positive electrode sheet of the present application is located between the current collector and the active material layer, which has a protective effect on the current collector and further improves the mechanical abuse safety of the battery.
  • the protective layer uses a conductive inactive layer instead of an insulating layer at the edge of the positive electrode tab side, thereby avoiding capacity loss in the transition zone and not affecting the capacity of the active material.
  • the inactive layer in the positive electrode sheet of the present application does not include a lithium-containing transition metal oxide, and due to the setting of the inactive layer region A, the width of the inactive layer exceeds the width of the positive electrode active material layer, thereby reducing the risk of lithium deposition.
  • the thickness of the inactive layer region A in the positive electrode sheet of the present application is greater than the thickness of region B, the thickness uniformity of the positive electrode sheet is better, the interface between the positive electrode sheet near the tab and the diaphragm and the negative electrode sheet is stronger, and the capacity retention rate is higher.
  • FIG1 is a left side view of the positive electrode sheet of Example 1.
  • FIG. 2 is a distribution diagram of the first region and the second region of the current collector in Example 1.
  • FIG. 2 is a distribution diagram of the first region and the second region of the current collector in Example 1.
  • FIG. 3 is a left side view of a positive electrode sheet according to another embodiment.
  • FIG4 is a schematic cross-sectional view of a battery cell structure.
  • FIG. 5 is a schematic diagram of the winding core structure.
  • FIG. 6A is a top view of the positive electrode undercoat sheet before die-cutting the tabs.
  • FIG. 6B is a top view of the positive electrode sheet after die-cutting the electrode tabs.
  • FIG. 7 is a left side view of the positive electrode sheet of Example 9.
  • FIG8 is a left side view of the positive electrode sheet of Example 11.
  • FIG. 9A is a top view of the positive electrode sheet of Comparative Example 1.
  • FIG. 9B is a left view of the positive electrode sheet of Comparative Example 1 along the dotted line area of FIG. 9A .
  • the present application discloses a positive electrode sheet and a method for preparing the same, and a battery and a method for preparing the same.
  • Those skilled in the art can refer to the contents of this article and appropriately improve the process parameters to achieve the same. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all deemed to be included in this application.
  • the methods and applications of this application have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of this application to implement and apply the technology of this application.
  • the reagents, instruments or materials used in this application can be obtained through commercial channels.
  • the battery of this embodiment includes a positive electrode sheet 100 , a separator 200 , a negative electrode sheet 300 , and an electrolyte.
  • the positive electrode sheet 100 (only the coating structure on one side of the positive electrode sheet is shown, and the inactive layer and active layer structure on the other side are not shown) includes a current collector 110, an inactive layer 120, an active material layer 130 and a tab 140.
  • the inactive layer 120 and the active material layer 130 are disposed on both sides of the current collector 110. It is disposed between the current collector 110 and the active material layer 130 .
  • both side surfaces of the current collector 110 include a first region 111 and a second region 112 , and the tab 140 is disposed at one end of the current collector 110 close to the first region 111 .
  • the inactive layer 120 includes region A 121 and region B 122, wherein region A 121 is disposed in the first region 111 and a portion of the lug surface, and region B 122 is disposed in the second region 112, and the thickness of region A 121 is greater than the thickness of region B 122.
  • the width of the inactive layer 120 is 102.5 mm, the width of the active material layer 130 is 100 mm, and the vertical distance that the edge of the inactive layer 120 exceeds the edge of the active material layer 130 is 2.5 mm.
  • the width of region A 121 is d 1
  • the width of region B 122 is d 2
  • the width of active material layer 130 is d 3 .
  • d 1 , d 2 , and d 3 satisfy the following relationship:
  • FIG. 4 is a cross-sectional schematic diagram of a battery cell structure composed of a positive electrode sheet 100 , a separator 200 , and a negative electrode sheet 300 (the negative electrode tab is not shown).
  • the vertical distance between the projection edge of the negative electrode sheet 300 on the side of the electrode tab in the length direction and the projection edge of the inactive layer 120 of the positive electrode sheet 100 on the side of the electrode tab in the length direction is d 4 .
  • d 5 The vertical distance between the projection edge of the active material layer 130 on the tab side in the length direction of the positive electrode sheet 100 and the projection edge of the inactive layer 120 on the tab side in the length direction of the positive electrode sheet 100 is d 5 , and d 4 and d 5 satisfy the following relationship:
  • FIG5 The schematic diagram of the winding core structure is shown in FIG5 .
  • Step 1 Prepare inactive layer slurry. Mix 97% by mass of ATO-coated TiO 2 (3% by mass of ATO and 94% by mass of TiO 2 ) and 3% by mass of PVDF, add a certain amount of NMP, adjust the solid content of the slurry to 40%, and stir to prepare the inactive layer slurry.
  • Step 2 Prepare positive electrode slurry. Mix 96% by weight of lithium cobalt oxide, 1% by weight of carbon black + 1% by weight of carbon nanotubes, and 2% by weight of PVDF, add a certain amount of NMP, adjust the solid content of the slurry to 70%, and stir to prepare the positive electrode slurry.
  • Step 3 Prepare negative electrode slurry. Mix 96% by weight of artificial graphite, 1% by weight of carbon black, 1.5% by weight of styrene-butadiene rubber + 1.5% by weight of sodium carboxymethyl cellulose, add deionized water, adjust the solid content of the slurry to 40%, and stir to prepare negative electrode slurry.
  • Step 4 Preparation of positive electrode sheet:
  • the inactive layer slurry of step 1 is coated on aluminum foil by gravure coating (the gravure roller is prepared by engraving different mesh numbers in different areas, and the engraving area of the corresponding inactive layer area A is 40 mesh, and the engraving area of area B is 120 mesh) to obtain a positive electrode bottom coating sheet.
  • the thickness of the inactive layer of the bottom coating sheet is different in different areas, wherein the thickness of area A is 20 ⁇ m, the thickness of area B is 5 ⁇ m, and the thickness of area A near one end of area B is gradually changing.
  • area A is a pentagonal right-angled trapezoid, and area B is a rectangle.
  • the positive active material of step 2 is coated on the inactive layer, and the positive electrode sheet is obtained after drying, as shown in Figure 6A.
  • Step 5 Preparation of negative electrode sheet: coating the negative electrode slurry in step 3 on copper foil through extrusion coating process to obtain a negative electrode sheet.
  • Step 6 Roll the positive and negative electrode sheets to the designed thickness, and then die-cut the tabs.
  • the schematic diagram of the positive electrode sheet after die-cutting the tabs is shown in FIG6B .
  • Step 7 Place the diaphragm between the positive and negative electrode sheets and wind them to obtain a roll core.
  • Use external Al (aluminum) tabs to weld the tabs of the positive electrode sheet together.
  • Use external nickel-plated copper tabs to weld the tabs of the negative electrode sheet together.
  • Use aluminum-plastic film to encapsulate the roll core and inject electrolyte.
  • Step 8 Use lithium-ion battery formation equipment to charge and discharge the battery cells to harden them and sort out the capacity of the battery cells.
  • Step 9 The battery cell is sealed for the second time and folded to make the battery cell basically formed.
  • Step 10 Perform an OCV test on the battery to determine the K value of the battery and select products with qualified K values.
  • the component of the inactive layer 120 is AZO-coated TiO 2 , and the rest is the same as in the first embodiment.
  • the component of the inactive layer 120 is ATO, and the rest is the same as in Example 1.
  • the component of the inactive layer 120 is AZO, and the rest is the same as in Example 1.
  • the composition of the inactive layer 120 is 97% carbon black coated Al 2 O 3 (the amount of carbon black is 3%, the amount of Al 2 O 3 is 94%) + 3% PVDF, and the rest is the same as in Example 1.
  • the composition of the inactive layer 120 is 94% Al 2 O 3 +3% carbon black +3% PVDF, and the rest is the same as in the first embodiment.
  • region A 121 of the inactive layer 120 is 20 ⁇ m
  • the thickness of region B 122 is 3 ⁇ m
  • the rest is the same as in Example 1.
  • region A 121 of the inactive layer 120 is 20 ⁇ m
  • the thickness of region B 122 is 1 ⁇ m
  • the rest is the same as in Example 1.
  • region A 121 of the inactive layer 120 is 5 ⁇ m
  • the thickness of region B 122 is 5 ⁇ m
  • the rest is the same as in Example 1.
  • the structure is shown in FIG7 .
  • the inactive layer 120 and the active material layer 130 are disposed on one surface of the current collector 110 , and the rest is the same as in the first embodiment.
  • area A 121 and area B 122 are both rectangular, and the rest are the same as in Example 1.
  • the width of the inactive layer 120 is 10.5 mm
  • the width of the active material layer 130 is 10 mm
  • the vertical distance from the edge of the inactive layer 120 to the edge of the active material layer 130 is 0.5 mm.
  • the width of the inactive layer 120 is 150 mm, the width of the active material layer 130 is 145 mm, and the vertical distance of the edge of the inactive layer 120 beyond the edge of the active material layer 130 is 5 mm. Others are the same as in Example 1.
  • the positive electrode sheet does not contain an inactive layer, and an insulating layer 150 of boehmite + PVDF (the mass ratio of boehmite to PVDF is 9:1) is provided near the tab. Its structure is shown in FIGS. 9A and 9B , and the rest is the same as in Example 1.
  • region A 121 of the inactive layer 120 is 20 ⁇ m
  • the thickness of region B 122 is 0 ⁇ m
  • the rest is the same as in Example 1.
  • the width of the inactive layer 120 is 75 mm, the width of the active material layer 130 is 75 mm, and the edge of the inactive layer 120 is flush with the edge of the active material layer 130. Others are the same as in Example 1.
  • a tungsten steel needle with a diameter of 3mm and a needle tip length of 3.62mm is inserted through the middle of the battery at a speed of 100mm/s. If the battery does not catch fire or explode, the test is considered to have passed.
  • the number of passes/the number of tests is the needle puncture pass rate, and the number of tests is 30.
  • Energy density E/(length ⁇ width ⁇ height of lithium-ion battery).
  • the lithium-ion battery is placed in a constant temperature environment of 45°C and charged and discharged at the designed charge and discharge rate for 500 cycles.
  • the first discharge capacity is recorded as C1
  • the 500th discharge capacity is recorded as C500.
  • the capacity retention rate after 500 cycles at 45°C is C500/C1.
  • the battery was cycled at 25°C and 3C/0.7C charge and discharge conditions, and disassembled at 200T ⁇ 700T to confirm the degree of lithium deposition.
  • 0, 1, 2, 3, 4, and 5 were used to represent the degree of lithium deposition. The larger the value, the more serious the lithium deposition.
  • Table 1 is the comparative data of the inactive layer composition, inactive layer thickness, needle penetration rate, energy density and capacity retention rate after 500 cycles at 45°C of each embodiment and comparative example.
  • an inactive layer 120 is provided between the active material layer 130 and the current collector 110, and the needle penetration rate is improved, wherein when the thickness of the inactive layer 120 exceeds 3 ⁇ m, the improvement is obvious.
  • Comparative Example 2 Compared with Comparative Example 1, in Comparative Example 2, there is an inactive layer 120 between the active material layer 130 and the current collector 110, and the conductive inactive layer 120 is near the pole ear 140, while in Comparative Example 1, there is an insulating layer 150 near the pole ear 140.
  • the capacity of Comparative Example 2 is higher than that of Comparative Example 1, and the energy density is improved by 5Wh/L.
  • the thickness of region A 121 of the inactive layer 120 in Example 1 is greater than the thickness of region B 122 of the inactive layer 120, the thickness uniformity of the positive electrode sheet is better, the interface between the positive electrode sheet near the tab and the separator and the negative electrode sheet is stronger, and the capacity retention rate is higher.
  • the inorganic particles in the inactive layer 120 are made of conductive materials. Compared with the design of insulating material inorganic particles + conductive agent in Example 6, in Example 5, the conductive agent is used to coat the inorganic particles of the insulating material. The conductive stability of the inactive layer 120 is better and the high-temperature cycle capacity retention rate is better, which is a preferred formula design.

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Abstract

本申请涉及电池技术领域，具体涉及一种正极片及其制备方法和一种电池及其制备方法。该正极片包括集流体、非活性层、活性物质层和极耳；非活性层和活性物质层设置于集流体至少一侧表面；所述活性物质层包括活性物质，所述非活性层不包括活性物质；沿极耳延伸的方向上，非活性层的边缘超出活性物质层的边缘。本申请设置的非活性层不仅对集流体有保护效果，还可以避免过渡带的容量损失，不影响活性物质的容量发挥。

Description

正极片及其制备方法、电池及其制备方法 技术领域
本申请涉及电池技术领域，具体涉及一种正极片及其制备方法、一种电池及其制备方法。
发明背景
多极耳卷绕及叠片结构的电芯，具有从极片延伸出的极耳，为防止制造过程中产生毛刺及正极活性物质能完全被负极活性物质覆盖以防止析锂，目前行业类通常做法是在正极片的出极耳的侧边涂覆一层绝缘层，以提升安全性。其示意图如图9A、图9B所示，图9A是极片的俯视图，图9B是极片沿图9A虚线区域的左视图。在正极片出极耳的侧边，靠近极片边缘及极耳上通常有0.5～5mm的绝缘层。绝缘层与活性物质层相互渗透，形成一定宽度的过渡带，在过渡带中绝缘层与活性物质层不规则分布。由于绝缘层不具有电子导通能力，过渡带中的活性物质参与电化学反应困难，难以进行锂离子的脱嵌，该部分正极活性物质的容量受到损失，降低了电池的整体容量。
发明内容
有鉴于此，本申请提供了一种正极片及其制备方法和一种电池及其制备方法。该正极片在集流体与活性物质层之间设置了一层非活性层，不仅对集流体有保护效果，还可以避免过渡带的容量损失，不影响活性物质的容量发挥。
为了实现上述发明目的，本申请提供以下技术方案：
本申请提供了一种正极片，该正极片包括集流体、非活性层、活性物质层和极耳；非活性层和活性物质层设置于集流体至少一侧表面，非活性层设置于集流体和活性物质层之间；所述活性物质层包括活性物质，所述非活性层不包括活性物质；沿极耳延伸的方向上，非活性层的边缘超出活性物质层的边缘。
本申请取消了极片靠近极耳端边缘的绝缘层，将非活性层延伸至原来设置绝缘层的位置，从而在非活性层与活性物质层之间不存在绝缘层与活性物质层相互渗透的过渡带，进而避免了过渡带的容量损失，不影响活性物质的容量发挥。
在本申请中，非活性层为不提供锂源的涂层，其具有导电作用。
作为优选，非活性层的边缘超出活性物质层的边缘垂直的距离为0.5～5mm。
在本申请实施方式中，非活性层的宽度为10.5～150mm，活性物质层宽度为 10～145mm。但本申请并非限定于此，只要保证非活性层的边缘超出活性物质层的边缘垂直的距离为0.5～5mm即可。
在本申请实施方式中，集流体至少一侧表面包括第一区域和第二区域，极耳设置于集流体靠近第一区域的一端；非活性层包括区域A和区域B，区域A设置于第一区域和部分极耳表面，区域B设置于第二区域。
作为优选，区域A的厚度大于等于区域B的厚度。更优选地，区域A的厚度大于区域B的厚度，此设计可更为有效地防止毛刺产生，更为有效地防止正极活性物质完全被负极活性物质覆盖的现象，提升安全性。
作为优选，区域A的厚度为1～50μm。
优选地，区域A的厚度为5～40μm。
在本申请具体实施方式中，区域A的厚度为5～20μm。
作为优选，区域B的厚度为0.1～20μm。
优选地，区域B的厚度为1～10μm。
在本申请具体实施方式中，区域B的厚度为1～5μm。
作为优选，区域A的宽度为d1，区域B的宽度为d2，活性物质层的宽度为d3，d1、d2、d3满足如下关系式：
d2≤d3<d1+d2。
在本申请具体实施方式中，当d2＝d3时，如图8所示，区域A和区域B在长度方向上的投影均为矩形。
在本申请另一具体实施方式中，当d2<d3<d1+d2时，如图3所示，区域A在长度方向上的投影为五边形类直角梯形，区域B在长度方向上的投影为矩形。但本申请并非限定于此，只要能实现本申请构思的技术方案均在本申请保护范围之内。
在本申请实施方式中，非活性层包括不含锂的无机颗粒和粘接剂。
在本申请实施方式中，不含锂的无机颗粒是指不包括含锂过渡金属氧化物的无机颗粒。
作为优选，不含锂的无机颗粒与粘接剂质量百分比为(80wt％～99wt％)：(1wt％～20wt％)。
优选地，不含锂的无机颗粒与粘接剂质量百分比为(90wt％～99wt％)：(1wt％～10wt％)。
作为优选，不含锂的无机颗粒包括导电材料和/或绝缘材料。
优选地，不含锂的无机颗粒包括导电材料，导电材料包括第一导电材料，和/或，包覆有第二导电材料的绝缘材料。
作为优选，第一导电材料包括但不限于ATO(掺Sb的SnO2)、FTO(掺F的SnO2)、ITO(掺Sn的In2O3)、AZO(掺Al的ZnO)中的至少一种。
作为优选，第二导电材料包括但不限于碳黑、碳纳米管、石墨烯、ATO、FTO、ITO、AZO中的至少一种。
在本申请另一实施方式中，不含锂的无机颗粒仅包括绝缘材料，非活性层还包括导电剂。
作为优选，导电剂包括但不限于炭黑、纳米碳管、石墨烯、碳纤维中的至少一种。
作为优选，绝缘材料包括但不限于氧化铝、氧化镁、氧化钛、氧化锌、氧化硅、勃姆石、氧化钴、磷酸铁、磷酸铝、偏磷酸铁、偏磷酸铝中的至少一种。
作为优选，粘接剂包括但不限于聚偏氟乙烯(PVDF)、丙烯酸改性PVDF、聚丙烯酸酯类聚合物、聚丙烯酸、聚丙烯盐、聚酰亚胺、丁苯橡胶、苯丙橡胶中的至少一种。
在本申请实施方式中，不含锂的无机颗粒为导电材料，不含锂的无机颗粒与粘接剂质量百分比为(80wt％～99wt％)：(1wt％～20wt％)。优选地，不含锂的无机颗粒与粘接剂质量百分比为(90wt％～99wt％)：(1wt％～10wt％)。
在本申请实施方式中，不含锂的无机颗粒为绝缘材料，非活性层还包括导电剂，不含锂的无机颗粒、导电剂与粘接剂质量百分比为(70wt％～98wt％)：(1wt％～15wt％)：(1wt％～15wt％)。优选地，不含锂的无机颗粒、导电剂与粘接剂质量百分比为(80wt％～98wt％)：(1wt％～10wt％)：(1wt％～10wt％)。
在本申请实施方式中，包覆有第二导电材料的绝缘材料中，第二导电材料与绝缘材料可以任意比例组成，包覆可为完全包覆，也可为不完全包覆。作为优选，第二导电材料与绝缘材料的质量比为(1～10)：(80～98)。
在本申请实施方式中，活性物质层包括正极活性物质，正极活性物质为含锂的过渡金属氧化物；
作为优选，含锂的过渡金属氧化物包括但不限于钴酸锂、镍钴锰酸锂、镍钴铝酸锂、磷酸铁锂、锰酸锂、富锂锰基材料中的至少一种。
作为优选，正极片中活性物质层中还包括导电剂和/或粘接剂。
作为优选，正极活性物质层中各组分的质量百分含量为：80wt％～99.8wt％的 正极活性物质、0.1wt％～10wt％的导电剂、0.1wt％～10wt％的粘接剂。
优选地，正极活性物质层中各组分的质量百分含量为：90wt％～99.6wt％的正极活性物质、0.2wt％～5wt％的导电剂、0.2wt％～5wt％的粘接剂。
本申请还提供了上述正极片的制备方法，包括如下步骤：
(1)将非活性层物料和第一溶剂混合，得到非活性层浆料，将非活性层浆料涂覆于集流体上，形成非活性层；
(2)将活性物质层物料和第二溶剂混合，得到活性物质层浆料，将活性物质层浆料涂覆于集流体的非活性层上，经干燥、辊压、模切出极耳后，得到正极片。
在本申请实施方式中，非活性层采用凹版涂覆的方式制备。
在本申请实施方式中，制备区域A的凹版涂覆的目数为10～80目。
在本申请实施方式中，制备区域B的凹版涂覆的目数为100～150目。
在本申请实施方式中，集流体为含铝的材料。
作为优选，含铝的材料包括铝箔、涂炭铝箔、铝聚合物复合集流体中的一种。
本申请还提供了一种电池，该电池包括负极片、隔膜和上述正极片。
在本申请实施方式中，负极片在长度方向上的极耳一侧的投影边缘与正极片中非活性层在长度方向上的极耳一侧的投影边缘之间的垂直距离为d4，正极片中活性物质层在长度方向上的极耳一侧的投影边缘与正极片中非活性层在长度方向上的极耳一侧的投影边缘之间的垂直距离为d5，d4、d5满足如下关系式：
d4<d5。
在本申请提供的实施例中，负极片包括负极集流体和涂覆在负极集流体一侧或两侧表面的负极活性物质层，负极活性物质层包括负极活性物质、导电剂和粘结剂。
作为优选，负极活性物质层中各组分的质量百分含量为：80wt％～99.8wt％的负极活性物质、0.1wt％～10wt％的导电剂、0.1wt％～10wt％的粘结剂。
优选地，负极活性物质层中各组分的质量百分含量为：90wt％～99.6wt％的负极活性物质、0.2wt％～5wt％的导电剂、0.2wt％～5wt％的粘结剂。
作为优选，负极活性物质包括碳基负极材料。
作为优选，碳基负极材料包括人造石墨、天然石墨、中间相碳微球、硬碳、软碳中的至少一种。
作为优选，负极活性物质还可进一步包括硅基负极材料。
作为优选，硅基负极材料选自纳米硅、硅氧负极材料(SiOx，0<x<2)或者 硅碳负极材料中的至少一种。
作为优选，负极活性物质中，碳基负极材料和硅基负极材料的质量比为10:0～1:19。
在本申请提供的具体实施例中，负极集流体为铜箔。
在本申请实施方式中，在正极片或负极片中，导电剂选自导电炭黑(乙炔黑和/或科琴黑)、导电石墨、导电碳纤维、碳纳米管、金属粉、碳纤维中的至少一种。
在本申请实施方式中，在正极片或负极片中，粘结剂选自PVDF、羧甲基纤维素钠、丁苯橡胶、聚四氟乙烯、聚氧化乙烯中的至少一种。
本申请还提供了上述电池的制备方法，包括如下步骤：
将正极片、隔膜和负极片层叠设置得到叠芯，或将正极片、隔膜和负极片层叠设置后再进行卷绕设置得到卷芯，将叠芯或卷芯置于外包装中，向外包装中注入电解液，经真空封装、静置、化成，得到本申请的电池。
与现有技术相比，本申请具有的有益效果为：
(1)本申请正极片中非活性层位于集流体与活性物质层之间，对集流体有保护效果，进一步改善电池的机械滥用安全性。
(2)本申请正极片中保护层在正极片出极耳侧边缘使用导电的非活性层替代绝缘层，避免了过渡带的容量损失，不影响活性物质的容量发挥。
(3)本申请正极片中非活性层不包括含锂过渡金属氧化物，且由于非活性层区域A的设置，非活性层的宽度区域超出正极活性物质层的宽度区域，降低析锂的风险。
(4)本申请正极片中非活性层区域A的厚度大于区域B的厚度，正极片厚度均一性更好，极耳附近的正极片与隔膜及负极片之间界面更牢固，容量保持率更高。
附图简要说明
图1为实施例1正极片左视图。
图2为实施例1集流体的第一区域和第二区域分布图。
图3为另一实施例正极片左视图。
图4为电芯结构剖面示意图。
图5为卷芯结构示意图。
图6A为模切极耳之前的正极底涂片俯视图。
图6B为模切极耳之后的正极片俯视图。
图7为实施例9正极片左视图。
图8为实施例11正极片左视图。
图9A为对比例1正极片俯视图。
图9B为对比例1正极片沿图9A虚线区域的左视图。
附图标记如下：
正极片100，正极集流体110，非活性层120，活性物质层130，活性物质层
的边缘131，正极极耳140，第一区域111，第二区域112，区域A 121，区域B122，非活性层的边缘123，绝缘层150，过渡带160；
隔膜200；
负极片300，负极极耳340；
X表示极片厚度方向，Y表示极片(集流体、非活性层或活性物质层)沿极
耳延伸的方向或宽度方向。
实施本发明的方式
本申请公开了一种正极片及其制备方法和一种电池及其制备方法，本领域技术人员可以借鉴本文内容，适当改进工艺参数实现。特别需要指出的是，所有类似的替换和改动对本领域技术人员来说是显而易见的，它们都被视为包括在本申请。本申请的方法及应用已经通过较佳实施例进行了描述，相关人员明显能在不脱离本申请内容、精神和范围内对本文所述的方法和应用进行改动或适当变更与组合，来实现和应用本申请技术。
本申请中所用试剂、仪器或材料等均可通过商业渠道获得。
下面结合实施例，进一步阐述本申请。
实施例1
1、电池结构
参考图1至图4，本实施例电池包括正极片100、隔膜200、负极片300和电解液。
如图1所示，正极片100(仅展示正极片单侧涂层结构，另一侧非活性层和活性层结构未示出)包括集流体110、非活性层120、活性物质层130和极耳140。集流体110两侧表面均设置有非活性层120和活性物质层130，非活性层120 设置于集流体110和活性物质层130之间。
如图2所示，集流体110两侧表面包括第一区域111和第二区域112，极耳140设置于集流体110靠近第一区域111的一端。
如图3所示(图3仅展示正极片单侧结构，另一侧非活性层和活性层结构未示出)，非活性层120包括区域A 121和区域B 122，所述区域A 121设置于第一区域111和部分极耳表面，所述区域B 122设置于第二区域112，所述区域A 121的厚度大于区域B 122的厚度。
非活性层120的宽度为102.5mm，活性物质层130的宽度为100mm，非活性层120的边缘超出活性物质层130的边缘垂直的距离为2.5mm。
区域A 121的宽度为d1，区域B 122的宽度为d2，活性物质层130的宽度为d3，d1、d2、d3满足如下关系式：
d2≤d3<d1+d2。
如图4所示，图4为正极片100、隔膜200、负极片300组成的电芯结构剖面示意图(负极极耳未示出)。
其中，负极片300在长度方向上的极耳一侧的投影边缘与正极片100中非活性层120在长度方向上的极耳一侧的投影边缘之间的垂直距离为d4。
正极片100中活性物质层130在长度方向上的极耳一侧的投影边缘与正极片100中非活性层120在长度方向上的极耳一侧的投影边缘之间的垂直距离为d5，d4、d5满足如下关系式：
d4<d5。
卷芯结构示意图如图5所示。
2、制备方法
第一步：制备非活性层浆料。将97％质量的ATO包覆的TiO2(ATO的量为3％，TiO2的量为94％)、3％质量的PVDF混合，加入一定量的NMP，将浆料固含调整至40％，经过搅拌配制成非活性层浆料。
第二步：制备正极浆料。将96％质量的钴酸锂、1％质量的炭黑+1％质量的碳纳米管、2％质量的PVDF混合，加入一定量的NMP，将浆料固含调整至70％，经过搅拌配制成正极浆料。
第三步：制备负极浆料。将96％质量的人造石墨、1％质量的炭黑、1.5％质量的丁苯橡胶+1.5％质量的羧甲基纤维素钠混合，加入去离子水，浆料固含调整至40％，经搅拌制备成负极浆料。
第四步：正极极片制备，将步骤一的非活性层浆料通过凹版涂覆方式(凹版辊采用不同区域雕刻不同目数的方式制备，对应非活性层区域A的雕刻区为40目，区域B的雕刻区为120目)涂覆在铝箔上，得到正极底涂片，该底涂片的非活性层在不同区域的厚度有差异，其中区域A厚度为20μm，区域B厚度为5μm，且区域A靠近区域B一端的厚度呈渐变的趋势，正极片左视图中区域A呈五边形类直角梯形，区域B呈矩形。再将步骤二的正极活性材料涂覆在非活性层上，烘干后得到正极极片，如图6A。
第五步：负极片制备，将步骤三的负极浆料通过挤压涂布的工艺涂覆在铜箔上得到负极片。
第六步：将正负极片辊压至设计厚度，然后模切出极耳，其中正极片的模切极耳后的示意图如图6B所示。
第七步：将隔膜放在正负极片中间进行卷绕，得到卷芯，使用外接Al(铝)极耳将正极片的各极耳焊接在一起，使用外接镀镍铜极耳将负极片的各极耳焊接在一起，使用铝塑膜将卷芯封装起来，注入电解液。
第八步：使用锂离子电池化成设备，对电芯进行充放电，使电芯硬化，并分选出电芯的容量。
第九步：电芯进行二次封口，并进行折边，使电芯基本成型。
第十步：对电池进行OCV测试，测试出电池的K值，挑选出K值合格的产品。
实施例2
非活性层120的组分为AZO包覆的TiO2，其余同实施例1。
实施例3
非活性层120的组分为ATO，其余同实施例1。
实施例4
非活性层120的组分为AZO，其余同实施例1。
实施例5
非活性层120的组分为97％炭黑包覆的Al2O3(炭黑的量为3％，Al2O3的量 为94％)+3％PVDF，其余同实施例1。
实施例6
非活性层120的组分为94％ Al2O3+3％炭黑+3％PVDF，其余同实施例1。
实施例7
非活性层120的区域A 121厚度为20，区域B 122厚度为3μm，其余同实施例1。
实施例8
非活性层120的区域A 121厚度为20，区域B 122厚度为1μm，其余同实施例1。
实施例9
非活性层120的区域A 121厚度为5μm，区域B 122厚度为5μm，其余同实施例1。其结构如图7所示。
实施例10
非活性层120和活性物质层130设置于集流体110一侧表面，其它同实施例1。
实施例11
如图8所示，区域A 121和区域B 122均呈矩形，其它同实施例1。
实施例12
非活性层120的宽度为10.5mm，活性物质层130的宽度为10mm，非活性层120的边缘超出活性物质层130的边缘垂直的距离为0.5mm。其它同实施例1。
实施例13
非活性层120的宽度为150mm，活性物质层130宽度为145mm，非活性层120的边缘超出活性物质层130的边缘垂直的距离为5mm。其它同实施例1。
对比例1
正极片不含有非活性层，靠近极耳处为勃姆石+PVDF(勃姆石与PVDF的质量比为9：1)的绝缘层150，其结构如图9A、图9B，其余同实施例1。
对比例2
非活性层120的区域A 121厚度为20，区域B 122厚度为0μm，其余同实施例1。
对比例3
非活性层120的宽度为75mm，活性物质层130宽度为75mm，非活性层120的边缘与活性物质层130的边缘平齐。其它同实施例1。
电池性能测试
(1)针刺测试：
将锂离子电池充满电，然后将其放入针刺测试设备的测试台上，将直径为3mm，针尖长度为3.62mm的钨钢针，以100mm/s的速度从电池的中间部位刺过并刺穿电池，电池不起火、不爆炸视为测试通过。通过数量/测试数量即为针刺通过率，测试数量为30个。
(2)能量密度：
将锂离子电池充电至上限电压4.45V，然后以0.2C放电至下限电压3.0V，放电能量记为E，然后通过以下公式计算出锂离子电池的能量密度：
能量密度＝E/(锂离子电池的长度×宽度×高度)。
(3)45℃循环500次容量保持率：
将锂离子电池置于45℃的恒温环境中以设计的充放电倍率进行充放电，循环充放电500次，记第一次放电容量为C1，第500次放电容量为C500，则45℃循环500次容量保持率为C500/C1。
(4)析锂情况
将电池在25℃条件下、3C/0.7C充放电制度下循环，并在200T\700T拆解确认其析锂程度，采用0、1、2、3、4、5代表析锂程度，数值越大析锂越严重。
表1为各实施例和对比例非活性层组分、非活性层厚度、针刺通过率、能量密度及45℃循环500次容量保持率对比数据。
表1不同实施例和对比例对比

实施例1-13，与对比例1相比，活性物质层130与集流体110之间有非活性层120，针刺通过率提升，其中当非活性层120厚度超过3μm，提升明显。
对比例2与对比例1相比，活性物质层130与集流体110之间有非活性层120，靠近极耳140处的是导电的非活性层120，对比例1靠近极耳140处的是绝缘层150，对比例2的容量发挥高于对比例1，能量密度有5Wh/L的提升。
实施例1与实施例9相比，非活性层120的区域A 121的厚度大于非活性层120的区域B 122的厚度，正极片厚度均一性更好，极耳附近的正极片与隔膜及负极片之间界面更牢固，容量保持率更高。
实施例5与实施例6相比，非活性层120中的无机颗粒选择导电材料，相较于实施例6的绝缘材料无机颗粒+导电剂的设计，实施例5采用导电剂包覆绝缘材料的无机颗粒，其非活性层120的导电稳定性更佳，高温循环容量保持率更好，为优选的配方设计。
以上所述仅是本申请的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本申请原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也应视为本申请的保护范围。

Claims (15)

  1. 一种正极片，其特征在于，所述正极片包括集流体、非活性层、活性物质层和极耳；所述非活性层和活性物质层设置于集流体至少一侧表面，所述非活性层设置于集流体和活性物质层之间；
    所述活性物质层包括活性物质，所述非活性层不包括活性物质；
    沿极耳延伸的方向上，所述非活性层的边缘超出所述活性物质层的边缘。
  2. 根据权利要求1所述的正极片，其特征在于，所述非活性层的边缘超出所述活性物质层的边缘垂直的距离为0.5～5mm。
  3. 根据权利要求1或2所述的正极片，其特征在于，所述集流体至少一侧表面包括第一区域和第二区域，所述极耳设置于集流体靠近第一区域的一端；
    所述非活性层包括区域A和区域B，所述区域A设置于第一区域和部分极耳表面，所述区域B设置于第二区域；
    所述区域A的厚度大于等于区域B的厚度。
  4. 根据权利要求3所述的正极片，其特征在于，所述区域A的厚度为1～50μm；所述区域B的厚度为0.1～20μm。
  5. 根据权利要求3所述的正极片，其特征在于，所述区域A的宽度为d1，所述区域B的宽度为d2，所述活性物质层的宽度为d3，d1、d2、d3满足如下关系式：
    d2≤d3<d1+d2。
  6. 根据权利要求1至5中任一项所述的正极片，其特征在于，所述非活性层包括不含锂的无机颗粒和粘接剂；所述不含锂的无机颗粒包括导电材料和/或绝缘材料。
  7. 根据权利要求6所述的正极片，其特征在于，所述不含锂的无机颗粒包括导电材料，所述导电材料包括第一导电材料，和/或，包覆有第二导电材料的绝缘材料。
  8. 根据权利要求7所述的正极片，其特征在于，所述第一导电材料包括ATO、FTO、ITO、AZO中的至少一种；
    和/或，所述第二导电材料包括碳黑、碳纳米管、石墨烯、ATO、FTO、ITO、AZO中的至少一种。
  9. 根据权利要求6所述的正极片，其特征在于，所述不含锂的无机颗粒仅包括绝缘材料，所述非活性层还包括导电剂。
  10. 根据权利要求9所述的正极片，其特征在于，所述导电剂包括炭黑、纳米碳管、石墨烯、碳纤维中的至少一种。
  11. 根据权利要求6-10中任一项所述的正极片，其特征在于，所述绝缘材料包括氧化铝、氧化镁、氧化钛、氧化锌、氧化硅、勃姆石、氧化钴、磷酸铁、磷酸铝、偏磷酸铁、偏磷酸铝中的至少一种；
    和/或，所述粘接剂包括PVDF、丙烯酸改性PVDF、聚丙烯酸酯类聚合物、聚丙烯酸、聚丙烯盐、聚酰亚胺、丁苯橡胶、苯丙橡胶中的至少一种。
  12. 根据权利要求1至11中任一项所述的正极片，其特征在于，所述活性物质层包括正极活性物质，所述正极活性物质为含锂的过渡金属氧化物；
    所述含锂的过渡金属氧化物包括钴酸锂、镍钴锰酸锂、镍钴铝酸锂、磷酸铁锂、锰酸锂、富锂锰基材料中的至少一种；
    所述集流体为含铝的材料；
    所述含铝的材料包括铝箔、涂炭铝箔、铝聚合物复合集流体中的一种。
  13. 一种电池，其特征在于，所述电池包括负极片、隔膜和权利要求1-12中任一项所述正极片；
    和/或，所述负极片在长度方向上的极耳一侧的投影边缘与正极片中非活性层在长度方向上的极耳一侧的投影边缘之间的垂直距离为d4，
    所述正极片中活性物质层在长度方向上的极耳一侧的投影边缘与正极片中非活性层在长度方向上的极耳一侧的投影边缘之间的垂直距离为d5，d4、d5满足如下关系式：
    d4<d5。
  14. 一种正极片的制备方法，其特征在于，包括：
    将非活性层物料和第一溶剂混合，得到非活性层浆料，将所述非活性层浆料涂覆于集流体上，形成非活性层；
    将活性物质层物料和第二溶剂混合，得到活性物质层浆料，将所述活性物质层浆料涂覆于所述集流体的所述非活性层上，经干燥、辊压、模切出极耳后，得到所述正极片。
  15. 一种电池的制备方法，其特征在于，包括：
    将权利要求1-12中任一项所述的正极片、隔膜和负极片层叠设置得到叠芯，或将所述正极片、所述隔膜和所述负极片层叠设置后再进行卷绕设置得到卷芯，将叠芯或卷芯置于外包装中，向外包装中注入电解液，经真空封装、静置、化成，得到所述电池。
PCT/CN2024/103973 2023-07-06 2024-07-05 正极片及其制备方法、电池及其制备方法 Ceased WO2025007968A1 (zh)

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CN115425233A (zh) * 2022-08-15 2022-12-02 珠海冠宇电池股份有限公司 一种正极片及其制备方法和一种锂电池

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