WO2023241165A1 - 一种极片及电池 - Google Patents

一种极片及电池 Download PDF

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Publication number
WO2023241165A1
WO2023241165A1 PCT/CN2023/084615 CN2023084615W WO2023241165A1 WO 2023241165 A1 WO2023241165 A1 WO 2023241165A1 CN 2023084615 W CN2023084615 W CN 2023084615W WO 2023241165 A1 WO2023241165 A1 WO 2023241165A1
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WO
WIPO (PCT)
Prior art keywords
pole piece
functional layer
region
groove
layer
Prior art date
Application number
PCT/CN2023/084615
Other languages
English (en)
French (fr)
Inventor
陈莎
周乔
李国梁
彭宁
Original Assignee
珠海冠宇电池股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Priority claimed from CN202221520256.1U external-priority patent/CN218385272U/zh
Priority claimed from CN202210688699.XA external-priority patent/CN115241415A/zh
Application filed by 珠海冠宇电池股份有限公司 filed Critical 珠海冠宇电池股份有限公司
Publication of WO2023241165A1 publication Critical patent/WO2023241165A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—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
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M4/134—Electrodes based on metals, Si or alloys

Definitions

  • the present application relates to the technical field of lithium-ion batteries, and in particular to a pole piece and a battery.
  • Lithium-ion batteries are widely used in electric vehicles, power tools and consumer electronics due to their high energy density and long service life.
  • the negative electrode sheet of the battery has become a hot topic of research by related companies.
  • lithium-ion battery negative electrode sheets mainly use graphite-based carbon-based negative electrode materials.
  • the energy density of negative electrode materials containing silicon has obvious advantages.
  • each silicon atom will be combined with 4.4 lithium atoms.
  • the lithium ions detached from the positive electrode cannot return from the silicon negative electrode.
  • the first efficiency is extremely low, only 69%, which reduces the utilization of lithium ions. rate, thereby reducing battery capacity.
  • the present application provides a pole piece and a battery to at least solve the first problem of low efficiency of lithium-ion batteries.
  • the present application provides a pole piece, including: a first current collector and a first functional layer provided on at least one side of the first current collector, and a plurality of first functional layers are spaced on the surface of the first functional layer.
  • a pole piece including: a first current collector and a first functional layer provided on at least one side of the first current collector, and a plurality of first functional layers are spaced on the surface of the first functional layer.
  • the pole piece provided by this application has several first regions and several second regions distributed at intervals on the surface of the first functional layer.
  • the first regions are used to supplement lithium materials.
  • the content of oxygen element and silicon element in the first functional layer is greater than 4:1, which ensures that lithium silicate is easily generated and can reduce the battery expansion rate during the cycle;
  • this application provides The pole piece is supplemented with lithium material, so that the battery processed by the pole piece provided by this application can make full use of the supplemented metal lithium to form an SEI film during the first charge and discharge process, reducing the loss of the positive lithium source, thereby improving the utilization rate of lithium ions. To achieve the effect of improving the first cycle efficiency of the battery.
  • the first region contains carbon element, oxygen element, fluorine element, phosphorus element and silicon element.
  • the content ratio of fluorine element to phosphorus element in the first functional layer is greater than 7:1.
  • the second region contains carbon element, oxygen element, fluorine element, phosphorus element and silicon element.
  • the content ratio S1:S2 of oxygen element and silicon element in the first functional layer satisfies: 2:1 ⁇ S1:S2 ⁇ 4:1 .
  • the content ratio S3:S4 of the fluorine element and the phosphorus element in the first functional layer satisfies: 6:1 ⁇ S3:S4 ⁇ 7:1 .
  • the content of fluorine element in the first functional layer located in the first region is greater than the content of fluorine element in the first functional layer located in the second region.
  • the content of phosphorus element in the first functional layer located in the first region is greater than the content of phosphorus element in the first functional layer located in the first region.
  • the content of oxygen element in the first functional layer located in the first region is greater than the content of oxygen element in the first functional layer located in the second region.
  • the width of the second region is 0 ⁇ m ⁇ 4 mm;
  • the width of the first region is 100 ⁇ m ⁇ 4mm.
  • the first functional layer includes active material particles
  • the active material particles include at least one of silicon material and silicon-oxygen material and a carbon material, wherein the mass of silicon material and/or silicon-oxygen material accounts for 7% to 50% of the total mass of the active material particles; or
  • the active material particles include carbon material and graphite; or
  • the active material particles include at least one of silicon material and silicon-oxygen material and a carbon material, wherein the mass of silicon material and/or silicon-oxygen material accounts for 7% to 50% of the total mass of the active material particles.
  • the extension direction of the first region and the width direction of the first functional layer form a first included angle, and the first included angle ranges from 0° to 45°; and/ or,
  • the ratio of the total area of the plurality of first regions to the total area of the second region is 0.7:1 to 3:1; and/or,
  • the part of the first area farthest from the first current collector is higher than the second area, and the part of the first area farthest from the first current collector
  • the difference in height from the second region farthest from the first current collector is 0.1 ⁇ m to 8 ⁇ m.
  • the pole piece further includes a first tab and a first glue layer formed on the surface of the first functional layer, and the first functional layer is provided with a first groove, at least Part of the first tab is located in the first groove and covered by the first glue layer, and the first glue layer covers at least one of the first areas.
  • the first groove has a first side, a second side and a third side, and is parallel to the first functional layer in a direction from the first side to the second side. length direction;
  • the portion of the first functional layer surface located on the first side of the first groove of the first glue layer covers 0 to 8 of the first areas; and/or,
  • the portion of the first functional layer surface located on the second side of the first groove of the first glue layer covers 0 to 8 of the first areas; and/or,
  • the portion of the first functional layer surface located on the third side of the first groove of the first glue layer covers 0 to 40 of the first areas; and/or,
  • the width of the portion of the first functional layer surface located on the first side of the first groove of the first glue layer in the length direction of the first functional layer is 1 mm to 5 mm; and/or,
  • the width of the portion of the first functional layer surface located on the second side of the first groove of the first glue layer in the length direction of the first functional layer is 1 mm to 5 mm.
  • This application also provides a battery, including a sealed case and a battery core located inside the sealed case.
  • the battery core includes a first pole piece and a second pole piece, and the first pole piece is the above-mentioned pole piece. , the polarity of the second pole piece is opposite to the polarity of the first pole piece.
  • a second glue layer is provided in an area where one end of the second pole piece is covered by the first pole piece; wherein the second glue layer corresponds to all parts of the first pole piece.
  • the number of the first areas is 0 to 20; and/or,
  • the second pole piece includes a second current collector and a second functional layer provided on the surface of the second current collector. There is a second empty foil at one end of the second pole piece without the second functional layer. area, the second glue layer covers at least part of the second empty foil area and extends from the second empty foil area to the surface of the second functional layer; and/or,
  • the width of the second glue layer in the length direction of the second pole piece is 3 mm to 5 mm.
  • the first functional layer is provided with a first groove
  • the surface of the second pole piece is provided with a third glue layer corresponding to the position of the first groove; and/or ,
  • the second pole piece includes a second current collector and a second functional layer provided on the surface of the second current collector.
  • the second functional layer is provided with a second groove and a second groove covering the second groove.
  • a fourth glue layer, the second pole piece is provided with a second pole tab, and the second pole tab is at least partially located in the second groove and covered by the fourth glue layer.
  • the first groove has a first side, a second side and a third side, and a first projection of the third glue layer on the first pole piece covers at least one of the The first area is satisfied: the part of the first projection located on the first side of the first groove covers 0 to 8 of the first areas; and/or,
  • the part of the first projection located on the second side of the first groove covers 0 to 8 of the first areas; and/or,
  • the part of the first projection located on the third side of the first groove covers 0 to 40 of the first areas; and/or,
  • the second groove has a fourth side, a fifth side and a sixth side, and the projection of the fourth glue layer on the first pole piece covers at least one of the first areas, and satisfies: the fourth The projection of the part of the glue layer located on the fourth side of the second groove on the first pole piece covers 0 to 8 of the first areas; and/or,
  • the projection of the part of the fourth glue layer located on the fifth side of the second groove on the first pole piece covers 0 to 8 of the first areas; and/or,
  • the projection of the part of the fourth glue layer located on the sixth side of the second groove on the first pole piece covers 0 to 40 of the first areas.
  • the content ratio of fluorine element and phosphorus element in the first region is greater than 7:1.
  • the excess fluorine element will chemically react with lithium ions to form lithium fluoride, a passivation layer.
  • the SEI film rich in LiF inert substances improves the stability of the SEI film, thereby improving the cycle stability of the silicon anode material.
  • the lithium ions in the positive electrode part are consumed in advance, resulting in low first efficiency of the battery; here, the supplementary metal lithium is fully utilized to form the SEI film, and after being processed into the battery, the loss of lithium source in the positive electrode sheet can be effectively reduced, thus Improve the utilization rate of lithium ions and achieve the effect of improving the first cycle efficiency of the battery.
  • the content ratio of fluorine element to phosphorus element is greater than 7:1, which enables the formation of an SEI film rich in LiF inert substances, improves the stability of the SEI film, and thereby improves the cycle stability of the silicon anode material.
  • first areas are separated by second areas, that is, every two adjacent first areas are separated by second areas that are not lithium replenished, so that the lithium replenishment area does not fully cover the entire
  • the electrolyte can more easily infiltrate the pole pieces, reducing the side reactions between metallic lithium and the electrolyte, thereby improving the utilization rate of lithium metal, optimizing the performance of the pole pieces and the battery, and increasing the capacity of the battery.
  • a first adhesive layer is provided on the surface of the first functional layer. The first adhesive layer covers at least one first area, which can prevent the problem of lithium deposition in the first area and improve the safety and other properties of the pole piece and battery.
  • pole pieces and batteries provided by this application can effectively improve the expansion effect of the battery, increase the number of charge and discharge cycles of the battery, and help extend the service life of the battery.
  • Figure 1 is a schematic structural diagram of a pole piece provided by an embodiment of the present application.
  • Figure 2 is an SEM image of the first region and the second region of the pole piece provided by the embodiment of the present application;
  • Figure 3 is an SEM image of the second region of the pole piece provided by the embodiment of the present application.
  • Figure 4 is a surface scan EDS image of an SEM image of the first region of the pole piece provided by the embodiment of the present application;
  • Figure 5 is a line scan of the first region and the second region of the pole piece provided by the embodiment of the present application.
  • Figure 6 is a distribution trend diagram of the phosphorus element at the position of the AB horizontal line in Figure 5 of the pole piece provided by the embodiment of the present application;
  • Figure 7 is a distribution trend diagram of the fluorine element at the position of the horizontal line AB in Figure 5 of the pole piece provided by the embodiment of the present application;
  • Figure 8 is a distribution trend diagram of the oxygen element at the position of the AB horizontal line in Figure 5 of the pole piece provided by the embodiment of the present application;
  • Figure 9 is a comparison chart of cycle performance curves between the battery provided by the embodiment of the present application and the existing battery;
  • Figure 10 is a comparison chart of the cycle performance expansion curves of the battery provided by the embodiment of the present application and the existing battery;
  • Figure 11 is a schematic cross-sectional structural diagram of the first pole piece perpendicular to the thickness direction of the negative electrode current collector according to the embodiment of the present application;
  • Figure 12 is a schematic cross-sectional structural diagram of the first pole piece perpendicular to the thickness direction of the negative electrode current collector according to the embodiment of the present application;
  • Figure 13 is a schematic cross-sectional structural diagram of the second pole piece perpendicular to the thickness direction of the negative electrode current collector according to the embodiment of the present application;
  • Figure 14 is a surface morphology diagram of the first pole piece provided by the embodiment of the present application measured by a 3D microscope;
  • Figure 15 is a schematic diagram of the placement structure of the lithium strip during the manufacturing process of the first pole piece provided by the embodiment of the present application.
  • 10-first current collector 11-first empty foil area; 20-first functional layer; 21-first groove; 22-first end coverage area; 23-second end coverage area; 30-th First region; 40-second region; 60-transition zone; 80-lithium belt; 81-first glue layer; 82-second glue layer; 84-fourth glue layer; 85-third region; 86-fourth area; 87-the fifth area; 91-the first tab; 92-the second functional layer; 921-the second groove; 93-the second empty foil area.
  • pole pieces made of silicon-oxygen anode materials have ideal specific capacities
  • the lithium ions extracted from the positive electrode will be embedded in the silicon-oxygen anode material and react with silicon-oxygen preferentially to form inactive substances such as lithium silicate and lithium.
  • Silicon alloys and silicon particles break, causing the solid electrolyte interface (SEI) film to grow, break, and repair repeatedly, causing the SEI film to accumulate in large quantities during the growth process, consuming lithium sources, causing capacity attenuation, low first efficiency, and poor circulation.
  • SEI solid electrolyte interface
  • the pole piece and battery provided by this application have several first regions 30 and several second regions 40 distributed at intervals on the surface of the first functional layer 20.
  • the first functional layer The ratio of oxygen to silicon in 20 is greater than 4:1, which ensures that lithium silicate is easily generated and can reduce the battery expansion rate during cycling.
  • the SEI film is formed by using supplementary metal lithium to reduce the loss of lithium ions in the positive electrode, thereby increasing the utilization rate of lithium ions and achieving the first improvement of the battery. Efficiency effect.
  • the present application provides a pole piece, including: a first current collector 10 and a first functional layer 20 disposed on at least one side of the first current collector 10 .
  • the surface of the first functional layer 20 has several spaced apart distributions.
  • the first functional layer 20 is an active material layer. Several first regions 30 and several second regions 40 are distributed at intervals on the surface of the first functional layer 20. The first regions 30 are used for supplementation. For lithium materials, in the first region 30, the content ratio of oxygen element to silicon element in the first functional layer 20 is greater than 4:1, which ensures that lithium silicate is easily generated and can reduce the battery expansion rate during cycling.
  • Electrolyte infiltration generally relies on capillary action.
  • This application provides a pole piece that adopts a structure in which second regions 40 and first regions 30 are alternately distributed.
  • the electrolyte can penetrate through the second region 40 to infiltrate the pole piece, reducing pole piece
  • the obstruction of infiltration is conducive to the uniform infiltration of the pole pieces, improving the battery infiltration effect, thereby increasing the cycle life of the battery.
  • the first region 30 contains carbon element, oxygen element, fluorine element, phosphorus element and silicon element; the second region 40 contains carbon element, oxygen element, fluorine element, phosphorus element and silicon element.
  • the content ratio of fluorine element to phosphorus element in the first functional layer 20 is greater than 7:1, which forms an SEI film rich in LiF inert substances, improves the stability of the SEI film, and thereby improves battery charging. Discharge cycle stability.
  • this application enables the battery processed by the pole pieces provided by this application to make full use of the supplemented metal lithium to form an SEI film during the first charge and discharge process, thereby reducing the loss of the positive lithium source and thus increasing the lithium
  • the utilization rate of ions achieves the effect of improving the first cycle efficiency of the battery.
  • the content ratio of oxygen element to silicon element may be 4:1, or 5:1, or 6:1, or 7: 1.
  • the content ratio of oxygen element to silicon element in the first region 30 is greater than 4:1, for example, the content ratio of oxygen element to silicon element is 5:1, excess oxygen element will compete with supplementary oxygen element.
  • the incoming lithium ions undergo a chemical reaction to generate lithium oxide or lithium carbonate, which will reduce the utilization rate of lithium ions.
  • a lithium material layer is provided on the surface of the first functional layer 20 to form the first region 30 , and the lithium contained in the lithium material layer has an areal density of 0.09 mg/cm 2 to 0.5 mg/cm 2 .
  • the lithium material layer may be disposed on the surface of the first functional layer 20 by rolling to form the first region 30 .
  • the lithium material layer may be a lithium foil.
  • the areal density of metallic lithium is 0.09 mg/cm 2 to 0.5 mg/cm 2 .
  • the first functional layer 20 includes graphite and silicon materials, where the mass of the silicon material accounts for 50% of the total mass of the active material particles. 7% to 50%, so that the amount of metallic lithium matches the amount of silicon material.
  • the lithium material layer may be a plurality of lithium ribbons.
  • the first functional layer 20 includes active material particles.
  • the active material particles include at least one of silicon material and silicon-oxygen material and a carbon material, wherein the mass of silicon material and/or silicon-oxygen material accounts for 7% to 7% of the total mass of the active material particles. 50%.
  • the areal density of metallic lithium contained in the first region 30 is 0.09 mg/cm 2 to 0.5 mg/cm 2 , so that the amount of metallic lithium matches the amount of silicon material and/or silicon-oxygen material. .
  • the active material particles include carbon material and graphite.
  • the areal density of metallic lithium is 0.09 mg/cm 2 to 0.5 mg/cm 2
  • the active material particles include at least one of silicon material and silicon-oxygen material and a carbon material, wherein the silicon material and /or the mass of the silicone material accounts for 7% to 50% of the total mass of the active material particles.
  • a pole piece provided by the present application is a negative pole piece.
  • the first current collector 10 can be made of copper foil, titanium foil, nickel mesh, stainless steel foil, or lithium copper alloy film. Or carbon cloth.
  • the first functional layer 20 is provided on both sides of the first current collector 10 .
  • the content ratio of fluorine element to phosphorus element in the first functional layer 20 is greater than 7:1.
  • the first functional layer 20 in the first region 30 is advanced.
  • a passivation reaction occurs when in contact with lithium ions, forming a passivation layer rich in LiF inert substances.
  • the passivation layer is the SEI film.
  • a SEI film rich in LiF inert substances is formed, which improves the stability of the SEI film. properties, thereby improving battery cycle stability.
  • the battery processed by the pole pieces provided by this application can make full use of the supplemented metal lithium to form an SEI film during the first charge and discharge process, thereby reducing the loss of the positive lithium source, thereby improving the performance of lithium ions. Utilization rate to achieve the effect of improving the first cycle efficiency of the battery.
  • the electrolyte is lithium hexafluorophosphate
  • the content ratio of fluorine element and phosphorus element in the first region 30 is greater than 7:1.
  • the excess fluorine element will chemically react with lithium ions to form an SEI film rich in LiF inert substances, improving the SEI. membrane stability, thereby improving battery cycle stability.
  • supplementary lithium is consumed in advance to form the SEI film, which reduces the consumption of positive electrode lithium, thereby improving charge and discharge efficiency.
  • Reference Figure 2 shows a picture obtained by photographing the first area 30 and the second area 40 using a scanning electron microscope (SEM) and magnifying it at 50x-5.0kx. It can be seen that the first area 30 and the second area 40 are photographed. Second area 40.
  • the second area 40 is used to create mutually spaced areas between adjacent first areas 30.
  • the second area 40 is a channel for the pole pieces to be infiltrated, which is beneficial to improving the infiltration effect of the pole pieces.
  • Asynchronous rolling technology may be used to prepare an ultra-thin metal lithium strip, and a metal lithium-containing region corresponding to the first region 30 and a metal-free region corresponding to the second region 40 are formed on the surface of the ultra-thin metal lithium strip.
  • the lithium ions in the metallic lithium strip are transferred to the first region 30, thereby forming the first region 30 on the surface of the first functional layer 20, and the second region 40 corresponds to the region that does not contain metallic lithium.
  • the width of the first region 30 is 100 ⁇ m ⁇ 4 mm, that is, the width of the two adjacent second regions
  • the spacing between 40 is 100 ⁇ m ⁇ 4mm.
  • the distance between two adjacent second regions 40 may be 100 ⁇ m, 1 mm, 2 mm, 3 mm or 4 mm.
  • the width of the second region 40 is 0 ⁇ m to 4 mm, that is, the spacing between two adjacent first regions 30 is 0 ⁇ m. ⁇ 4mm.
  • the present application provides a pole piece.
  • the distance between two adjacent first regions 30 may be 10 ⁇ m, 1 mm, 2 mm, 3 mm or 4 mm.
  • the lithium ions After the lithium ions are locally embedded in the silicon particles located in the first region 30, they will migrate to the non-embedded lithium ion region due to the concentration difference and potential difference, thereby forming a transition region 60 between the first region 30 and the second region 40, and causing Lithium ions are evenly distributed inside the first region 30, thereby achieving a consistent lithium insertion state, avoiding problems of lithium precipitation and purple spots due to excessive local lithium ions, thereby improving the uniformity of the overall lithium insertion.
  • the pole pieces are replenished with lithium.
  • the metal lithium in the first area 30 reacts with silicon to generate lithium silicate as a buffer layer to alleviate the expansion of the battery during the cycle. It is located in the third area.
  • the content ratio of oxygen element to silicon element in the first functional layer 20 in one region 30 is >4:1; in the second region 40, the content ratio S1 of oxygen element and silicon element in the first functional layer 20 is: S2 satisfies: 2:1 ⁇ S1:S2 ⁇ 4:1, and oxygen is located in the first area
  • the content of the oxygen element in the first functional layer 20 of the domain 30 is greater than the content of the oxygen element in the first functional layer 20 located in the second region 40 .
  • the SEI film In order to prevent the silicon particles from cracking during the lithium insertion process, the SEI film repeatedly grows, cracks, and repairs, causing a large amount of SEI film to accumulate during the growth process, consuming lithium ions, resulting in battery capacity attenuation, low first efficiency, poor cycle, and poor structure.
  • the SEI film containing LiF inert material improves the stability of the SEI film, thereby improving the cycle stability of the silicon anode material.
  • the content ratio of fluorine element and phosphorus element in the first functional layer 20 located in the first region 30 is >7:1.
  • the content ratio S3:S4 of the fluorine element and the phosphorus element in the first functional layer 20 satisfies: 6:1 ⁇ S3:S4 ⁇ 7:1.
  • the content of fluorine element in the first functional layer 20 located in the first region 30 is greater than the content of fluorine element in the first functional layer 20 located in the second region 40 .
  • the content of the phosphorus element in the first functional layer 20 located in the first region 30 is greater than the content of the phosphorus element in the first functional layer 20 located in the first region 30 .
  • This application also provides a battery, including a sealed case and a battery core located inside the sealed case.
  • the battery core includes a first pole piece and a second pole piece, and the first pole piece is the above-mentioned pole piece.
  • the active material particles of the first functional layer 20 include graphite and silicon-oxygen material.
  • the mass proportion of the silicon-oxygen material can be 7% of the total mass of the active material particles.
  • the metal contained in the first region 30 The areal density of lithium can be 0.12.
  • the content ratio of oxygen element to silicon element is S1:S2: 5:1.
  • the content ratio of fluorine element to phosphorus element is S3: S4 is 7:1.
  • the content ratio S1:S2 of the oxygen element and the silicon element is 4:1.
  • the content ratio S3:S4 of the fluorine element and the phosphorus element is 6:1.
  • the active material particles of the first functional layer 20 include graphite and silicon-oxygen material.
  • the mass proportion of the silicon-oxygen material can be 20% of the total mass of the active material particles.
  • the metal lithium contained in the first region 30 The areal density may be 0.22.
  • the content ratio of oxygen element to silicon element is S1:S2, which is 6:1.
  • the content ratio of fluorine element to phosphorus element is S3:S4. is 7.5:1.
  • the content ratio S1 : S2 of oxygen element and silicon element is 4:1.
  • the content ratio S3 : S4 of fluorine element and phosphorus element is 6:1.
  • the active material particles of the first functional layer 20 include graphite and silicon-oxygen material.
  • the mass proportion of the silicon-oxygen material can be 30% of the total mass of the active material particles.
  • the metal lithium contained in the first region 30 The areal density may be 0.32.
  • the content ratio of oxygen element to silicon element is S1:S2.
  • the content ratio of fluorine element to phosphorus element is S3:S4. is 8:1.
  • the content ratio S1:S2 of the oxygen element and the silicon element is 4:1.
  • the content ratio S3:S4 of the fluorine element and the phosphorus element is 6:1.
  • the active material particles of the first functional layer 20 include graphite and silicon-oxygen material.
  • the mass proportion of the silicon-oxygen material can be 40% of the total mass of the active material particles.
  • the metal lithium contained in the first region 30 The areal density may be 0.42.
  • the content ratio of oxygen element to silicon element is S1:S2.
  • the content ratio of fluorine element to phosphorus element is S3:S4. is 8.5:1.
  • the oxygen and silicon elements The content ratio S1:S2 is 4:1.
  • the content ratio S3:S4 of fluorine element and phosphorus element is 6:1.
  • the active material particles of the first functional layer 20 include graphite and silicon-oxygen material.
  • the mass proportion of the silicon-oxygen material can be 50% of the total mass of the active material particles.
  • the metal lithium contained in the first region 30 The areal density may be 0.5.
  • the content ratio of oxygen element to silicon element is S1:S2.
  • the content ratio of fluorine element to phosphorus element is S3:S4. It’s 9:1.
  • the content ratio S1:S2 of the oxygen element and the silicon element is 4:1.
  • the content ratio S3:S4 of the fluorine element and the phosphorus element is 6:1.
  • the active material particles of the first functional layer 20 include graphite and silicon-oxygen material.
  • the mass proportion of the silicon-oxygen material can be 7% to 50% of the total mass of the active material particles.
  • the graphite can be Artificial graphite, natural graphite or modified graphite, the metallic lithium contained in the first region 30 has an areal density of 0.09 mg/cm 2 to 0.5 mg/cm 2 . This allows the amount of metallic lithium to match the amount of silicon particles.
  • the active material particles of the first functional layer 20 include graphite and silicon-oxygen material.
  • the mass proportion of the silicon-oxygen material can be 7% of the total mass of the active material particles.
  • the metallic lithium contained in the first region 30 The areal density can be 0.18.
  • the content ratio of oxygen element to silicon element is S1:S2 is 6:1.
  • the content ratio of fluorine element to phosphorus element is S3:S4. 7:1.
  • the content ratio S1:S2 of the oxygen element and the silicon element is 4:1.
  • the content ratio S3:S4 of the fluorine element and the phosphorus element is 6:1.
  • the active material particles of the first functional layer 20 include graphite and silicon-oxygen material.
  • the mass proportion of the silicon-oxygen material can be 30% of the total mass of the active material particles.
  • the metal lithium contained in the first region 30 The areal density can be 0.28.
  • the content ratio of oxygen element to silicon element is S1:S2, which is 7.5:1.
  • the content ratio of fluorine element to phosphorus element is S3:S4. is 8:1.
  • the content ratio S1:S2 of the oxygen element and the silicon element is 4:1.
  • the content ratio S3:S4 of the fluorine element and the phosphorus element is 6:1.
  • the active material particles of the first functional layer 20 include graphite and silicon-oxygen material.
  • the mass proportion of the silicon-oxygen material can be 50% of the total mass of the active material particles.
  • the metal lithium contained in the first region 30 The areal density may be 0.34.
  • the content ratio of oxygen element to silicon element is S1:S2.
  • the content ratio of fluorine element to phosphorus element is S3:S4. is 8.5:1.
  • the content ratio S1:S2 of the oxygen element and the silicon element is 4:1.
  • the content ratio S3:S4 of the fluorine element and the phosphorus element is 6:1.
  • the active material particles of the first functional layer 20 include graphite and silicon-oxygen material, in which the mass proportion of the silicon-oxygen material can be 7% to 50% of the total mass of the active material particles, correspondingly , the surface density of metallic lithium contained in the first region 30 is 0.09 mg/cm 2 to 0.5 mg/cm 2 .
  • the amount of metallic lithium matches the amount of silicon particles, which not only avoids excess metallic lithium causing reaction and precipitation of lithium with the electrolyte, reducing the utilization rate of lithium ions, but also avoids If the amount of metallic lithium is too small, the effect of lithium supplementation will not be obvious, and the first efficiency improvement will not be obvious.
  • the first functional layer 20 is coated on the surface of the first current collector 10, it is baked in a dry environment at a temperature of 90°C for 24 hours so that the moisture is controlled below 300 ppm to obtain a semi-finished pole piece, which is then asynchronously rolled.
  • the ultra-thin metal lithium strip is prepared using the technology, and is laminated with the semi-finished pole piece to prepare the pole piece.
  • This application also provides a battery, including a sealed case and a battery core located inside the sealed case.
  • the battery core includes a first pole piece and a second pole piece, and the first pole piece is the above-mentioned pole piece.
  • the second pole piece is a positive pole piece
  • the first pole piece is a negative pole piece
  • the first pole piece, the second pole piece and the isolation film are stacked in order so that the isolation film is between the first pole piece and the second pole piece, and the isolation film serves to isolate the first pole piece and the second pole piece.
  • the battery core is then wound to obtain the battery core.
  • the battery core is placed in a sealed case, and electrolyte is injected into the sealed case.
  • the battery core is charged at a constant current of 0.1C to a 4% state of charge (state of charge). State of Charge (SOC for short), then charging to 10% SOC with 0.2C constant current, shaping, capacity testing and other processes to obtain a soft-pack lithium-ion battery.
  • the sealed case may be an aluminum plastic film
  • the electrolyte may be lithium hexafluorophosphate
  • the first region 30 is a lithium-supplemented region
  • the second region 40 is a non-lithium-supplemented region. After 3D microscopy testing, the first region 30 is brighter and the second region 40 is darker (as shown in Figure 14 shown).
  • lithium can be replenished according to the following process: as shown in FIG. 15 , multiple lithium strips 80 are spacedly distributed on the surface of the first functional layer 20 , and there are exposed third lithium strips 80 between the multiple lithium strips 80 .
  • the second area 40 facilitates the wettability of the electrolyte to the electrode piece and improves the utilization rate of the lithium belt. Optimize pole piece and battery performance.
  • the pole piece precursor formed with the first functional layer 20 can be baked at about 90°C for about 24 hours in a dry environment to control the moisture below 300 ppm, and then the lithium belt 80 is placed On the surface of the baked pole piece, after lamination and other treatments, the lithium strip 80 is compounded with the first functional layer 20 to replenish lithium.
  • the above-mentioned pole piece can be produced by a coating method.
  • the preparation process generally includes ingredients (preparing slurry), coating (coating the slurry on the surface of the current collector base material to form the first functional layer 20), rolling, and separation. Cutting (cutting according to the preset size and shape of the pole piece and other parameters), baking and other steps, and then subsequent processes such as lithium replenishment.
  • the lithium strips 80 used may include short lithium strips whose length is smaller than the width of the first functional layer 20 (the short lithium strips are distributed as shown in Figure 15, and the surface topography of the pole piece formed by them is as shown in Figure 15. As shown in FIG.
  • multiple short lithium strips can be placed sequentially along the width direction of the first functional layer 20 (the direction shown by arrow B) to form a row, and then follow this process, along the first functional layer 20
  • the length direction (the direction shown by arrow A) forms another column, and the length of each column may be less than or equal to the width of the pole piece (the length of the column formed by the arrangement of the first region 30 thus formed is less than or equal to the width of the pole piece) width), but is not limited to this, multiple short lithium strips can also be distributed irregularly on the surface of the first functional layer 20, or long lithium strips with a length substantially the same as the width of the first functional layer 20 can be used. Distributed on the surface of the first functional layer 20 (for example, there is a gap between any two adjacent long lithium strips, and after chemical formation, the gap is formed Second area 40).
  • the amount of lithium strip 80 can satisfy: the total mass of lithium strip 80 disposed on the surface of first functional layer 20 and the total mass of lithium strip 80 on the surface of first functional layer 20 (the side away from first current collector 10 ).
  • the area ratio is 0.09 ⁇ 0.5mg: 1m2 .
  • the thickness of the lithium strip 80 may be 1.9 ⁇ m-9 ⁇ m. Due to the extremely high theoretical specific capacity of pure metallic lithium, if the entire surface of the pole piece is replenished with lithium, the thickness of the metallic lithium usually needs to be about 1 ⁇ m. , the preparation is extremely difficult and the consistency is very poor.
  • an ultra-thin metal lithium belt is used to replenish lithium with non-full surface coverage.
  • the ultra-thin metal lithium belt exhibits discontinuous stripes/ripples and other discontinuities on the surface of the first functional layer 20 In the covering state, it can effectively replenish lithium and improve the utilization rate of lithium metal. It also has the advantages of simple preparation and good consistency.
  • the lithium ingot is generally pressed to a thickness of micron level, and then the obtained micron level lithium strip is placed on the surface of the first functional layer 20 to replenish lithium.
  • a lithium ingot of 200 ⁇ m to 2 mm is rolled into a lithium strip 80 with a thickness of 1.9 ⁇ m to 9 ⁇ m, and then placed on the surface of the first functional layer 20 to replenish lithium.
  • the inorganic salt layer may be an inorganic salt layer formed by embedding the active material particles in the first region 30 with a lithium-supplemented lithium source. That is, the material constituting the inorganic salt layer is an inorganic salt. The salt layer is generated by embedding the lithium element supplemented in the first region 30 into the active material particles of the first region 30 .
  • the inorganic salt layer includes, for example, at least one of lithium fluoride, lithium carbonate, lithium silicate, and the like.
  • the first regions 30 and the second regions 40 are staggered/distributed alternately, that is, the first functional layer 20 has multiple first regions 30 and multiple second regions 40 distributed on the surface.
  • the second regions 40 space the surface of the first functional layer 20 to form a plurality of first regions 30 .
  • the plurality of first regions 30 may be distributed along the length direction of the first functional layer 20/pole piece (the direction indicated by arrow A). That is, the plurality of first regions 30 and the plurality of second regions 40 may be distributed along the length direction of the first functional layer 20/pole piece.
  • the length directions of the functional layers 20/pole pieces are staggered in sequence.
  • the extension direction/length direction of the first region 30 may form a first included angle with the width direction of the first functional layer 20 .
  • the angle may range from 0° to 60°.
  • the first included angle may range from 0° to 45°, such as 0° (that is, the length direction of the first region 30 and the width of the first functional layer 20 direction parallel), 10°, 20°, 30°, 40° or 45°, etc., which is beneficial to the lithium replenishment of the pole piece and the electrolyte infiltration effect, while not affecting the winding of the pole piece along its length direction, which is conducive to the production of batteries and performance.
  • the extending directions of the plurality of first regions 30 may be the same or different, that is, the first included angles formed with the width direction of the first functional layer 20 may be the same or different.
  • the distance between the first region 30 closest to the outer edge/edge of the first functional layer 20 and the outer edge of the first functional layer 20 is A, and A can be 0-2mm, such as 0 (that is, the first area 30 is flush with the outer edge of the first functional layer 20), 0.5mm, 1mm, 1.5mm, 2mm, etc.; the ratio of A to the width of the first functional layer 20 can be 0 ⁇ 0.03, such as 0, 0.01, 0.02, 0.03, etc.
  • a column is formed by at least one first region 30, and the column may be in a continuous state, that is, the column is formed by one first region 30 (with the middle region Will not be included in the second district domain 40 discontinuous), or the column may also be in a discontinuous state, that is, the column is composed of a plurality of first regions 30 sequentially arranged along the width direction of the first functional layer 20, where there is a third region between adjacent two regions 30.
  • the second area 40 is interrupted by the second area 40 .
  • the first region 30 extends along the width direction of the first functional layer 20.
  • the first region 30 may have a substantially straight structure, or may have a bent/curved structure.
  • the distance between the first region 30 closest to the outer edge of the first functional layer 20 and the outer edge of the first functional layer 20 (that is, the distance closest to the first functional layer 20
  • the width of the second region 22 on the outer edge of the first functional layer 20 in the length direction of the first functional layer 20 may be 0-4 mm, for example, 100 ⁇ m-4 mm.
  • the first functional layer 20 has an opposite first end and a second end, the direction from the first end to the second end is parallel to the length direction of the first functional layer 20 , and the direction closest to the first end is
  • the distance w1 between the first region 30 and the first end edge of the first functional layer 20 (edge of the first functional layer 20) is 100 ⁇ m to 4 mm, such as 100 ⁇ m, 300 ⁇ m, 500 ⁇ m, 700 ⁇ m, 1 mm, 2 mm, 3 mm, 4 mm, etc., that is,
  • the width of the second region 40 existing between the first region 30 closest to the first end and the edge of the first end is w1; the width closest to the second end (first function
  • the distance w2 between the first region 30 (edge of the layer 20) and the second end edge of the first functional layer 20 is 0 ⁇ m to 4 mm, such as 0, 100 ⁇ m, 300 ⁇ m, 500 ⁇ m, 700 ⁇ m, 1 mm
  • w1 and w2 may be the same or different.
  • the total area of the plurality of first regions 30 ie, the sum of the areas of the plurality of first regions 30
  • the area of the plurality of second regions 40 are The ratio of the total area (that is, the sum of the areas of the plurality of second regions 40 ) is 0.7:1 to 3:1, such as 0.7:1, 1:1, 1.5:1, 2:1, 2.5:1, or 3:1. 1 etc.
  • a microscope may be used to capture the outlines of the first regions 30 and the second regions 40 to determine the ratio of the total area of the plurality of first regions 30 to the total area of the plurality of second regions 40 .
  • the first region 30 is higher than the second region 40 , that is, along the thickness of the first functional layer 20 direction, the distance a from the part of the first region 30 farthest from the first current collector 10 to the first current collector 10 is greater than the distance b(a) from the part of the second region 40 farthest from the first current collector 10 to the first current collector 10 >b).
  • the method of measuring the height difference between the first area 30 and the second area 40 may include Including but not limited to the following methods: (1) Use ion grinding (CP) equipment to sputter the lithium-replenishing electrode piece to obtain a cross-section, then use a scanning electron microscope (SEM) to photograph, and magnify to the required magnification to photograph, and obtain Height difference; (2) Use a 3D microscope to magnify to the required magnification for shooting, and then use a profilometer to measure the height difference.
  • CP Use ion grinding
  • SEM scanning electron microscope
  • the first functional layer 20 is provided with a first groove 21 , and the first glue layer 81 covers the first groove 21 .
  • the first groove 21 can be used as a tab groove for setting the tab.
  • the pole piece also includes a first tab 91 and a first glue layer formed on the surface of the first functional layer 20 81, at least part of the first tab 91 is located in the first groove 21 and covered by the first glue layer 81 (that is, the part of the first tab 91 located in the first groove 21 is covered by the first glue layer 81), In this way, the tab area can be protected and the safety of the pole piece and battery can be improved. For example, lithium in the lithium supplement area around the first tab can be prevented from migrating to the positive tab area (corresponding to the tab where the positive tab is located) during the charge and discharge process. groove), and the resulting lithium precipitation problem in the negative electrode ear area.
  • the first glue layer 81 is disposed on a partial area of the surface of the first functional layer 20 , that is, it does not completely cover the first functional layer 20 .
  • the first glue layer 81 covers at least one first area 30 .
  • At least part of the bottom surface of the first groove 21 is the surface of the first current collector 10 , that is, part of the bottom surface of the first groove 21 exposes the first current collector 10 , and the first tab 91 can It is connected to the first current collector 10 with the bottom surface of the first groove 21 exposed. Specifically, it may be welded to the first current collector 10 with the bottom surface of the first groove 21 exposed.
  • the pole piece can be a pole-tab center structure (CPT), that is, the pole tab is arranged in the middle of the pole piece instead of the end.
  • CPT pole-tab center structure
  • the first groove 21 are the first functional layer 20 .
  • one side of the first groove 21 is flush with one long side of the first current collector 10 , and the other sides are surrounded by the first functional layer 20 , that is, the first groove 21 has an opening toward one long side of the first current collector 10 .
  • the first tab 91 is set, one end of the first tab 91 can extend out of the outer edge of the first current collector 10 through the opening.
  • the first tab 91 extends out of the outer edge of the first current collector 10 through the opening along its length direction, and the part of the first tab 91 located in the first groove 21 (that is, does not extend out of the first current collector) 10) is covered by the first glue layer 81 (as shown in Figure 12).
  • the length direction of the first tab 91 is parallel to the length direction of the first region 30/the second region 40 (that is, the extension directions of the first tab 200 and the first region 30/the second region 40 are consistent).
  • the projection of the first groove 21 on the first current collector 10 is a rectangle, one of its short sides is flush with one of the long sides of the first current collector 10 , and the remaining three sides are surrounded by the first functional layer 20 .
  • the first groove 21 has opposite first and second sides, and opposite third and fourth sides, and the third/fourth sides are located between the first side and the second side. Between the sides (the third side/the fourth side connects the first side and the second side), the direction from the first side to the second side is parallel to the direction along the first area to the second area.
  • the first side is the left side
  • the second side is the right side
  • the third side is the lower side
  • the fourth side is the upper side.
  • the left and right sides of the first groove 21 are Both sides and lower sides are surrounded by the first functional layer 20, and there is no first functional layer 20 on the upper side (that is, the upper side of the first groove 21 is flush with the edge of the first functional layer 20).
  • the direction from the first side to the second side is parallel to the length direction of the first functional layer 20
  • the direction from the third side to the fourth side is parallel to the width direction of the first functional layer 20 .
  • the first glue layer 81 extends to the surface of the first functional layer 20 around the first groove 21, and the first glue layer 81 is located at Part of the surface of the first functional layer 20 on the first side of the first groove 21 covers a1 first areas 30, where a1 is 0 to 8, such as 0, 1, 2, 3, 4, 5, 6, 7, 8, etc. , that is, the number of first areas located on the first side of the first groove 21 and in contact with the first glue layer 81 is a1, that is, the surface of the first functional layer 20 includes areas located on the first side of the first groove 21 and by The number of the third areas 85 covered by the first adhesive layer 81 and extending into the first areas 30 in the third area 85 is a1.
  • the portion of the first glue layer 81 located on the second side of the first groove 21 on the surface of the first functional layer 20 covers a2 first areas 30, and a2 is 0 to 8, that is, the portion located on the second side of the first groove 21 and
  • the number of first regions 30 in contact with the first glue layer 81 is a2, that is, the surface of the first functional layer 20 includes a fourth region 86 located on the second side of the first groove 21 and covered by the first glue layer 81 , the number of first areas 30 extending into the fourth area 86 is a2.
  • the portion of the first glue layer 81 located on the surface of the first functional layer 20 on the third side of the first groove 21 is in contact with a3 first regions 30, where a3 is 0 to 40, such as 0, 2, 5, 8, 10 , 12, 15, 18, 20, 22, 25, 28, 30, 32, 35, 38, 40, etc., that is, the first area 30 located on the third side of the first groove 21 and in contact with the first glue layer 81
  • the number is a3, that is, the surface of the first functional layer 20 includes the fifth area 87 located on the third side of the first groove 21 and covered by the first glue layer 81, extending to the first area 30 in the fifth area 87.
  • the quantity is a3 pieces.
  • a3 is also the total number of the first areas 30 in contact with the first adhesive layer 81 .
  • the width w31 (also the width w31 of the portion of the surface of the first functional layer 20 on the first side of the first groove 21 along the length direction of the first functional layer 20 of the first glue layer 81
  • the width of the three regions 85 along the length direction of the first functional layer 20 is 1 mm to 5 mm, such as 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc.
  • the width w32 of the portion of the surface of the first functional layer 20 on the second side of the first groove 21 of the first glue layer 81 along the length direction of the first functional layer 20 (also the width w32 of the fourth region 86 along the first functional layer 20
  • the width of the functional layer 20 in the length direction is 1 mm to 5 mm, such as 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc.
  • w31 and w32 can be the same or different.
  • the total width of the first glue layer 81 along the length direction of the first functional layer 20 is substantially equal to the sum of w31, the width of the first groove 21 along the length direction of the first functional layer 20, and w32.
  • any first region 30 is The length of the first functional layer 20 in the width direction is equal to the length of the first functional layer 20 where it is located, for example, the length of the first region 30 located on opposite sides (the first side and the second side) of the first groove 21 The length is equal to the width of the portions of the first functional layer 20 located on opposite sides of the first groove 21 .
  • the length direction of the first functional layer 20 is also the length direction of the first current collector 10
  • the width direction of the first functional layer 20 is also the width direction of the first current collector 10
  • the width of the first current collector 10 is basically equal to the first functional layer 20 .
  • the maximum width of the layer 20 ie, the width of the portion of the first functional layer 20 located on opposite sides of the first groove 21 in FIGS. 11 and 12 ).
  • At least one end of the first current collector 10 may also be provided with a first empty foil area 11 in which the first functional layer 20 is not provided.
  • An embodiment of the present application also provides a battery, including a first pole piece, a separator, and a second pole piece with a polarity opposite to that of the first pole piece, which are stacked in sequence.
  • the first pole piece includes the above-mentioned pole piece.
  • the battery includes a battery core
  • the battery core includes a first pole piece, a separator, and a second pole piece that are stacked in sequence.
  • the battery core may be composed of a first pole piece, a separator, and a second pole piece.
  • a wound battery core is formed by stacking the pole pieces in sequence and then winding them.
  • the first pole piece/separator/second pole piece can be wound along the length direction to form a wound battery core.
  • the first pole piece, the separator, and the second pole piece each have a bent portion and a straight portion connected to both ends of each bent portion.
  • the direction from one bent portion to the other bent portion is parallel to the roll.
  • the length direction of the wound battery core and the direction from one straight part to the other straight part are parallel to the width direction of the wound battery core.
  • the diaphragm plays an isolation role and is used to separate the first pole piece and the second pole piece to prevent the two from contact and short circuit.
  • the thickness of the diaphragm can be 5 to 16 ⁇ m, such as 5 ⁇ m, 8 ⁇ m, 10 ⁇ m, 13 ⁇ m, 16 ⁇ m, etc.
  • the thickness of the diaphragm can be It is a conventional membrane in the art, such as a coated membrane including a substrate or a coating coated on the substrate.
  • the second pole piece includes a second current collector and a second functional layer 92 disposed on the surface of the second current collector.
  • the second pole piece has two opposite ends (referred to as fifth ends respectively). and the sixth end), at least one end of which has a second empty foil area 93 that is not provided with a coating.
  • the rest of the second pole piece is provided with a second functional layer 92.
  • the part where the second functional layer 92 and the second empty foil area 93 are connected usually has an uneven structure.
  • at least one end of the second pole piece can be covered by the first pole piece.
  • the second glue layer 82 is provided in the portion where the second pole piece is covered by the first pole piece, which is usually also the part where the second pole piece is covered by the separator.
  • the second functional layer 92 is the active material layer of the second pole piece.
  • a second glue layer 82 is provided in the area where one end (fifth end) of the second pole piece is covered by the first pole piece.
  • the second glue layer 82 corresponds to the first region 30 of the first pole piece.
  • the quantity is x, 0 ⁇ x ⁇ 20, x is, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20.
  • the first pole piece has two opposite ends (recorded as the third end and the fourth end respectively), and one end (the third end) has a first The end covering area 22, the first end covering area 22 and the second glue layer 82 of the second pole piece are positioned correspondingly, that is, the first end covering area 22 and the second glue layer 82 cover each other (the second glue layer 82 is on The projection on the first pole piece substantially coincides with the first end covering area 22), and the width W4 of the first end covering area 22 in the length direction of the first pole piece/second pole piece is equal to the width W4 of the second glue layer 82 in the length direction of the first pole piece/second pole piece.
  • the width w6 of the second glue layer 82 in the length direction of the second pole piece is 3 mm to 5 mm, for example, w6 is 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm, etc.
  • the second glue layer 82 covers at least part of the second empty foil area 93 and is separated from the second empty foil area 93 extends to the surface of the second functional layer 92 .
  • the other end (fourth end) of the first pole piece has a second end covering area 23 covering the other end (sixth end) of the second pole piece, that is, the second pole piece
  • the projection of the sixth end on the first pole piece is located in the second end coverage area 23 and does not exceed the second end coverage area 23.
  • the width w5 of the second end coverage area 23 in the length direction of the first pole piece is 3 to 5 mm, such as 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc.
  • the surface of the second pole piece is provided with a third glue layer corresponding to the position of the first tab 91/first groove 21 of the first pole piece.
  • the projection of the third glue layer on the first pole piece can be Covering the first groove 21 further prevents lithium deposition from the negative electrode.
  • the first projection of the third glue layer on the first pole piece covers at least one first area 30, and satisfies that: the part of the first projection located on the first side of the first groove 21 covers 0 to 8 first areas 30, For example, 0, 1, 2, 3, 4, 5, 6, 7, 8, etc., which may or may not be equal to a1; the part of the first projection located on the second side of the first groove 21 covers 0 to 8 first areas 30 , such as 0, 1, 2, 3, 4, 5, 6, 7, 8, etc., which may or may not be equal to a2; the part of the first projection located on the third side of the first groove 21 covers 0 to 40 first areas 30, such as 0, 2, 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35, 38, 40, etc., may or may not be equal to a3.
  • the width of the portion of the first projection located on the first side of the first groove 21 along the length direction of the first functional layer 20 may be 1 mm to 5 mm, such as 1 mm, 1.5 mm, 2 mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, etc., which may or may not be equal to w31; the width of the portion of the first projection located on the second side of the first groove 21 along the length direction of the first functional layer 20 It can be 3mm ⁇ 5mm, such as 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, etc., and it can be equal to or not equal to w32.
  • the first projection of the third glue layer on the first pole piece may cover the first glue layer 81 or be covered by the first glue layer 81, and the two may overlap, for example.
  • the second pole piece is provided with a second tab, and in the width direction of the battery core, the first tab 91 and the second tab do not overlap, that is, the first tab 91 is perpendicular to the battery core.
  • the projection in the width direction of the core does not overlap with the projection of the second tab perpendicular to the width direction of the battery core.
  • the second functional layer 92 is provided with a second groove 921 and a fourth glue layer 84 covering the second groove 921.
  • the second tab is at least partially located within the second groove 921 and is surrounded by the fourth glue layer 84. Covered by the glue layer 84 (that is, the part of the second tab located in the second groove 921 is covered by the second glue layer 82).
  • the second groove 921 serves as a tab groove for arranging the tab, and at least part of its bottom surface is the second current collector surface (that is, part of its bottom surface exposes the second current collector).
  • the second tab can be connected to the second current collector exposed on the bottom surface of the second groove 921, specifically, it can be welded to the second current collector exposed on the bottom surface of the second groove 921.
  • the second pole piece may have a pole-tab-centered structure, that is, the second pole tab is disposed in the middle of the second pole piece instead of the end.
  • At least two sides of the second groove 921 are the second functional layer 92 .
  • one side of the second groove 921 is flush with one long side of the second current collector, and the other sides are covered by the second current collector.
  • the functional layer 92 surrounds, that is, the second groove 921 has an opening toward one long side of the second current collector. After the second tab is set, one end of the second tab can extend out of the outer edge of the second current collector through the opening.
  • the second pole protrudes from the outer edge of the second current collector through the opening along its length direction, and the portion of the second pole located within the second groove 921 (that is, does not protrude from the outer edge of the first current collector 10 edge) is covered by the second glue layer 82.
  • the length direction of the second pole tab is parallel to the width direction of the second pole piece.
  • the projection of the second groove 921 on the second current collector is a rectangle, one short side of which is flush with a long side of the second current collector, and the remaining three sides are surrounded by the second functional layer.
  • the fourth glue layer 84 extends to the surface of the second functional layer 92 around the second groove 921 and is bonded to the second functional layer 92 around the second groove 921 .
  • the second groove 921 has a fourth side, a fifth side and a sixth side, and the direction from the fourth side to the fifth side is parallel to the length direction of the second pole piece, and the fourth glue
  • the projection of the layer 84 on the first pole piece covers at least one first area 30, and satisfies the following requirements: the projection of the part of the fourth glue layer 84 located on the fourth side of the second groove on the first pole piece covers 0 to 8 first areas.
  • the part of the fourth glue layer 84 located on the fifth side of the second groove is on the first pole piece
  • the projection covers 0 to 8 first areas 30, such as 0, 1, 2, 3, 4, 5, 6, 7 or 8, etc., which may or may not be equal to a2; the fourth glue layer 84 is located in the second groove and the sixth
  • the projection of the side part on the first pole piece covers 0 to 40 first areas 30, such as 0, 2, 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35 , 38 or 40, etc., which may or may not be equal to a3.
  • the width of the portion of the fourth glue layer 84 located on the fourth side of the second groove along the length direction of the second pole piece may be 1 mm to 5 mm, such as 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc., may or may not be equal to w31; the width of the part of the fourth glue layer 84 located on the fifth side of the second groove along the length direction of the second pole piece may be 3mm ⁇ 5mm, such as 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc., which may or may not be equal to w32.
  • the shape, size and other parameters of the second groove 921 may be the same as or different from the first groove 21
  • the shape, area and other parameters of the fourth glue layer 84 may be the same as the first glue layer 81 Or different.
  • the thickness of the first glue layer 81, the second glue layer 82, the third glue layer and the fourth glue layer 84 can be 10-16 ⁇ m respectively, such as 10 ⁇ m, 11 ⁇ m, 12 ⁇ m, 13 ⁇ m, 14 ⁇ m, 15 ⁇ m, 16 ⁇ m, etc.
  • the specific It can be tape.
  • a certain glue layer (or its projection) covering the first region 30 refers to the opposite sides of the first region 30 covered by the glue layer in the length direction of the first functional layer 20 are located within the projection of the glue layer on the surface of the first functional layer 20 (that is, the first area 30 covered by the glue layer does not protrude from the outer edge of the projection of the glue layer on the surface of the first functional layer 20), and In the width direction of the first functional layer 20, the first area 30 covered by the glue layer may be partially located within the projection of the glue layer on the surface of the first functional layer 20, and partially located within the projection of the glue layer on the surface of the first functional layer 20. Outside the projection on the surface, or entirely within the projection of the glue layer on the surface of the first functional layer 20 .
  • the first glue layer 81 covers four first areas 30.
  • the opposite sides of the four first regions 30 are located within the projection of the first adhesive layer 81 on the surface of the first functional layer 20, and in the width direction of the first functional layer 20, the four first regions 30 are The first region 30 partially extends into the projection of the first glue layer 81 on the surface of the first functional layer 20 and is partially located outside the projection of the first glue layer 81 on the surface of the first functional layer 20 .
  • the above-mentioned battery may include a lithium-ion battery, which can be prepared by conventional methods in the art.
  • the preparation process generally includes steps such as winding, packaging, liquid injection, aging, chemical formation, second sealing, sorting, and packaging.
  • the first pole piece, separator, and second pole piece can be stacked and then rolled to form a bare battery core.
  • the bare battery core can be placed in an outer packaging foil (such as aluminum-plastic film), and then electrolyte can be injected into the battery core.
  • liquid and then go through processes such as vacuum packaging, standing, formation (such as 0.1C constant current charging to 4% SOC (state of charge), and then 0.2C constant current charging to 10% SOC), shaping, etc., to make soft package lithium ions.
  • Battery can be prepared by conventional methods in the art.
  • the preparation process generally includes steps such as winding, packaging, liquid injection, aging, chemical formation, second sealing, sorting, and packaging.
  • the first pole piece, separator, and second pole piece can be
  • Test 1 Surface morphology test of the first area 30 and the second area 40
  • SEM scanning electron microscope
  • the spacing between adjacent second regions 40 that is, the width of the first region 30, is listed.
  • the spacing between adjacent first regions 30, that is, the width of the second region 40 is listed.
  • Test 2 Test the elements in the first area 30 and the second area 40
  • a pole piece provided in the embodiment of the present application is selected, and the position of the SEM collection picture is tested and analyzed using an X-ray energy spectrometer (EDS).
  • EDS X-ray energy spectrometer
  • Figure 3 is a 500x electron microscope picture.
  • the EDS surface scan image is shown in Figure 4, which is the 500x surface scan EDS image of the dotted line position in the dotted line box in Figure 3.
  • an X-ray energy spectrometer (EDS) is used to test the element distribution at the horizontal line AB in FIG. 5 .
  • the measured SEM element content line scans are shown in Figure 6, Figure 7 and Figure 8.
  • Figure 6 shows the distribution trend of phosphorus element.
  • the abscissa indicates the position, and the ordinate indicates the content of phosphorus element. It can be seen from Figure 6 that from the first area 30 to the second area 40, the content of phosphorus element decreases.
  • Figure 7 shows the distribution trend of fluorine element.
  • the abscissa indicates the position, and the ordinate indicates the fluorine element content. It can be seen from Figure 7 that from the first area 30 to the second area 40, the content of fluorine element decreases.
  • Figure 8 shows the distribution trend of oxygen element.
  • the abscissa indicates the position, and the ordinate indicates the content of oxygen element. It can be seen from Figure 8 that from the first area 30 to the second area 40, the content of oxygen element decreases.
  • the two pairs The only difference between the batteries selected by the comparison group and the batteries selected by the two experimental groups is that the batteries selected by the two experimental groups use the electrode plates provided by this application as negative electrode plates, while the batteries selected by the comparison group use conventional negative electrode plates. Does not contain metallic lithium.
  • the testing process includes the following steps:
  • Step 1 Let the battery stand for 10 minutes at a temperature of 5°C ⁇ 2°C;
  • Step 2 Discharge the battery to the lower limit voltage at a battery discharge rate of 0.2C and let it stand for 10 minutes;
  • Step 3 Charge the battery to the upper limit voltage at a battery charging rate of 0.7C, cut off at 0.05C, and let it sit for 10 minutes;
  • Step 4 Discharge the battery to the lower limit voltage at a battery discharge rate of 0.2C, and then perform an initial capacity test;
  • Step 5 Let the battery stand for 10 minutes
  • Step 6 Charge the battery to the upper limit voltage at a battery charging rate of 3C, cut off at 0.05C, and then test the battery thickness;
  • Step 7 Let the battery stand for 10 minutes at a temperature of 25°C ⁇ 2°C;
  • Step 8 Discharge the battery to the lower limit voltage at a battery discharge rate of 1C and let it stand for 10 minutes;
  • Step 9 Charge the battery to the upper limit voltage at a battery charging rate of 3C, cut off at 0.05C, and let it sit for 10 minutes;
  • Step 9 Repeat steps 8 and 9 1000 times. After every 50 cycles from 0 to 200 cycles, test the thickness of the battery in the fully charged state. From 200 to 1000 cycles, after every 50 cycles, test the thickness of the battery. After 100 cycles, test the thickness of the battery in the fully charged state, and repeat steps 3 and 4 for capacity testing at a temperature of 25°C. After 1,000 cycles, test the thickness of the battery in the fully charged state. thickness.
  • the 3V capacity of Experimental Group 1 to Experimental Group 4 is significantly improved.
  • the first area 30 of the pole piece uses metallic lithium with different areal densities, and the battery capacity is improved. and reach the target capacity value.
  • step 9 The test results of step 9 are shown in Figure 10. It can be seen from Figure 10 that the abscissa represents the number of charge and discharge cycles, and the ordinate represents the expansion rate.
  • the battery provided by this patent has a lower expansion rate when fully charged than the existing battery. The battery has a significant effect on improving the expansion of the battery.
  • FIG. 9 a comparison chart of the cycle performance curves of the battery provided by this application and the existing battery is shown.
  • the abscissa represents the number of charge and discharge cycles, and the ordinate represents the capacity retention rate of the battery.
  • the battery provided by this patent After completing 450 charge and discharge cycles of the battery, the battery capacity is reduced to 80%. After the existing battery completes 350 charge and discharge cycles, the battery capacity is reduced to 80%. Therefore, the battery provided by this patent has a battery cycle The performance is improved by about 100 charge and discharge cycles, and the corresponding battery capacity retention rate is increased by about 5% to 15%. This shows that through improvements in this patent, the capacity of the battery is significantly improved, and the cycle performance of the battery is also significantly improved.
  • first and second are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Therefore, features defined as “first” and “second” may explicitly or implicitly include one or more of these features.
  • “plurality” means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

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Abstract

本申请提供一种极片及电池，其中，本申请提供一种极片，包括：第一集流体和设置在所述第一集流体至少一面的第一功能层，所述第一功能层的表面间隔分布有若干个第一区域和若干个第二区域；在所述第一区域内，所述第一功能层中的氧元素与硅元素的含量占比大于4：1。本申请提供的一种极片及电池，用以至少解决锂离子电池首次效率低的问题，提高电池容量，从而提高电池能量密度。

Description

一种极片及电池
本申请要求于2022年06月17日提交中国专利局、申请号为202210688699.X、申请名称为“一种极片及电池”的中国专利申请，和于2022年06月17日提交中国专利局、申请号为202221520256.1、申请名称为“极片及电池”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及锂离子电池技术领域，尤其涉及一种极片及电池。
背景技术
锂离子电池由于具有能量密度高，使用寿命长等优点，被广泛应用于电动汽车、电动工具及消费电子领域。为了提高锂离子电池的能量密度，电池的负极片成为相关企业研究的热点。
目前，商业化的锂离子电池负极片主要使用石墨类碳基负极材料，与石墨相比，采用含有硅负极材料的能量密度优势明显。然而，在实际的充放电过程中，平均每个硅原子将结合4.4个锂原子，从正极脱出的锂离子无法从硅负极返回，首效极低，仅为69％，降低了锂离子的利用率，从而降低了电池容量。
因此，亟需解决锂离子电池首次效率低的问题。
发明内容
本申请提供一种极片及电池，用以至少解决锂离子电池首次效率低的问题。
为了实现上述目的，本申请提供一种极片，包括：第一集流体和设置在所述第一集流体至少一面的第一功能层，所述第一功能层的表面间隔分布有若干个第一区域和若干个第二区域；在所述第一区域内，所述第一功能层中的氧元素与硅元素的含量占比大于4：1。
本申请提供的极片，通过在所述第一功能层的表面间隔分布有若干个所述第一区域和若干个所述第二区域，所述第一区域用于补充锂材料，在所述第一区域内，所述第一功能层中的氧元素与硅元素的含量占大于4：1，这样确保容易生成锂硅酸盐，可以降低循环过程中的电池膨胀率；本申请通过提前给极片补充锂材料，使得本申请提供的极片加工的电池在首次充放电的过程中，充分利用补充的金属锂形成SEI膜，减少正积极锂源的损失，从而提高锂离子的利用率，达到改善电池的首次循环效率的效果。
在一种可能实施的方式中，所述第一区域内具有碳元素、氧元素、氟元素、磷元素和硅元素。
在一种可能实施的方式中，在所述第一区域内，所述第一功能层中的氟元素与磷元素的含量占比大于7：1。
在一种可能实施的方式中，所述第二区域内具有碳元素、氧元素、氟元素、磷元素和硅元素。
在一种可能实施的方式中，在所述第二区域内，所述第一功能层中的氧元素与硅元素的含量占比S1：S2满足：2：1≤S1：S2≤4:1。
在一种可能实施的方式中，在所述第二区域内，所述第一功能层中的氟元素和磷元素的含量占比S3：S4满足：6：1≤S3：S4≤7:1。
在一种可能实施的方式中，位于所述第一区域的所述第一功能层中的氟元素的含量大于位于所述第二区域的所述第一功能层中的氟元素的含量。
在一种可能实施的方式中，位于所述第一区域的所述第一功能层中的磷元素的含量大于位于所述第一区域的所述第一功能层中的磷元素的含量。
在一种可能实施的方式中，位于所述第一区域的所述第一功能层中的氧元素的含量大于位于所述第二区域的所述第一功能层中的氧元素的含量。
在一种可能实施的方式中，所述第二区域的宽度为0μm～4mm；和/或
所述第一区域的宽度为100μm～4mm。
在一种可能实施的方式中，所述第一功能层包括活性材料颗粒；
所述活性材料颗粒包括硅材料和硅氧材料中的至少一种以及碳材料，其中硅材料和/或硅氧材料的质量占所述活性材料颗粒的总质量的7％～50％；或
所述活性材料颗粒包括碳材料和石墨；或
所述活性材料颗粒包括硅材料和硅氧材料中的至少一种以及碳材料，其中硅材料和/或硅氧材料的质量占所述活性材料颗粒的总质量的7％～50％。
在一种可能实施的方式中，所述第一区域的延伸方向与所述第一功能层的宽度方向形成第一夹角，所述第一夹角的范围为0°～45°；和/或，
多个所述第一区域的总面积与所述第二区域的总面积之比为0.7：1～3：1；和/或，
以所述第一集流体的表面为基准，所述第一区域最远离所述第一集流体的部位高于所述第二区域，所述第一区域最远离所述第一集流体的部位与所述第二区域最远离所述第一集流体的部位的高度之差为0.1μm～8μm。
在一种可能实施的方式中，所述极片还包括第一极耳和形成在所述第一功能层表面上的第一胶层，所述第一功能层设有第一凹槽，至少部分所述第一极耳位于所述第一凹槽内并被所述第一胶层覆盖，且所述第一胶层覆盖至少一个所述第一区域。
在一种可能实施的方式中，所述第一凹槽具有第一侧、第二侧和第三侧，沿所述第一侧至所述第二侧的方向平行于所述第一功能层的长度方向；其中，
所述第一胶层位于所述第一凹槽第一侧的所述第一功能层表面的部分覆盖0～8个所述第一区域；和/或，
所述第一胶层位于所述第一凹槽第二侧的所述第一功能层表面的部分覆盖0～8个所述第一区域；和/或，
所述第一胶层位于所述第一凹槽第三侧的所述第一功能层表面的部分覆盖0～40个所述第一区域；和/或，
所述第一胶层位于所述第一凹槽第一侧的所述第一功能层表面的部分在所述第一功能层的长度方向上的宽度为1mm～5mm；和/或，
所述第一胶层位于所述第一凹槽第二侧的所述第一功能层表面的部分在所述第一功能层的长度方向上的宽度为1mm～5mm。
本申请还提供一种电池，包括密封壳体和位于所述密封壳体内部的电芯，所述电芯包括第一极片和第二极片，所述第一极片为上述的极片，所述第二极片的极性与所述第一极片的极性相反。
在一种可能实施的方式中，所述第二极片的一端被所述第一极片覆盖的区域设有第二胶层；其中，所述第二胶层对应的第一极片的所述第一区域的数量为0～20个；和/或，
所述第二极片包括第二集流体、以及设于所述第二集流体表面的第二功能层，所述第二极片的一端存在未设置所述第二功能层的第二空箔区，所述第二胶层覆盖至少部分所述第二空箔区、并从所述第二空箔区延伸至所述第二功能层的表面；和/或，
所述第二胶层在所述第二极片的长度方向上的宽度为3mm～5mm。
在一种可能实施的方式中，所述第一功能层设有第一凹槽，所述第二极片表面设有与所述第一凹槽的位置对应的第三胶层；和/或，
所述第二极片包括第二集流体、以及设于所述第二集流体表面的第二功能层，所述第二功能层设有第二凹槽、以及覆盖所述第二凹槽的第四胶层，所述第二极片设有第二极耳，所述第二极耳至少部分位于所述第二凹槽内并被所述第四胶层覆盖。
在一种可能实施的方式中，所述第一凹槽具有第一侧、第二侧和第三侧，所述第三胶层在所述第一极片上的第一投影覆盖至少一个所述第一区域，且满足：所述第一投影位于所述第一凹槽第一侧的部分覆盖0～8个所述第一区域；和/或，
所述第一投影位于所述第一凹槽第二侧的部分覆盖0～8个所述第一区域；和/或，
所述第一投影位于所述第一凹槽第三侧的部分覆盖0～40个所述第一区域；和/或，
所述第二凹槽具有第四侧、第五侧和第六侧，所述第四胶层在所述第一极片上的投影覆盖至少一个所述第一区域，且满足：所述第四胶层位于所第二凹槽第四侧的部分在所述第一极片上的投影覆盖0～8个所述第一区域；和/或，
所述第四胶层位于所述第二凹槽第五侧的部分在所述第一极片上的投影覆盖0～8个所述第一区域；和/或，
所述第四胶层位于所述第二凹槽第六侧的部分在所述第一极片上的投影覆盖0～40个所述第一区域。
本申请提供的极片及电池，所述第一区域的氟元素和磷元素的含量占比大于7：1， 多出的氟元素会与锂离子发生化学反应生成氟化锂，即钝化层。富含LiF惰性物质的SEI膜，提高SEI膜的稳定性，从而提高硅负极材料的循环稳定性。SEI膜在形成过程中，提前消耗正极部分的锂离子，导致电池首效低；在此充分利用补充的金属锂形成SEI膜，加工成电池后，可以有效减少正极片中锂源的损失，从而提高锂离子的利用率，达到改善电池的首次循环效率的效果。
本申请提供的极片及电池，氟元素与磷元素的含量占比大于7：1，使得形成富含LiF惰性物质的SEI膜，提高SEI膜的稳定性，从而提高硅负极材料的循环稳定性。
本申请提供的极片及电池，多个第一区域由第二区域间隔，即每两个相邻的第一区域被未进行补锂的第二区域间隔开，使得补锂区域未全面覆盖整个第一功能层表面，通过第二区域，电解液更易于浸润极片，减少金属锂与电解液的副反应，从而提高锂金属利用率，优化极片和电池的性能,对电池的容量提升效果明显，并且电池的循环性能的提升效果也明显。此外，在第一功能层表面设有第一胶层，第一胶层覆盖至少一个第一区域，可以防止该第一区域产生析锂的问题，提高极片和电池的安全性等性能。
本申请提供的极片及电池，能够有效改善电池的膨胀效应，提高电池的充放电循环次数，有利于延长电池的使用寿命。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作以简单地介绍，显而易见地，下面描述中的附图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性的前提下，还可以根据这些附图获得其他的附图。
图1为本申请实施例提供的极片的结构示意图；
图2为本申请实施例提供的极片的第一区域与第二区域获取的SEM图；
图3为本申请实施例提供的极片的第二区域的SEM图；
图4为本申请实施例提供的极片的第一区域的SEM图的面扫EDS图；
图5为本申请实施例提供的极片的第一区域和第二区域的线扫图；
图6为本申请实施例提供的极片的图5中的AB横线位置的磷元素的分布趋势图；
图7为本申请实施例提供的极片的图5中的AB横线位置的氟元素的分布趋势图；
图8为本申请实施例提供的极片的图5中的AB横线位置的氧元素的分布趋势图；
图9为本申请实施例提供的电池与现有的电池的循环性能曲线对比图；
图10为本申请实施例提供的电池与现有的电池的循环性能膨胀曲线对比图；
图11为本申请实施例提供的第一极片垂直于负极集流体厚度方向的截面结构示意图；
图12为本申请实施例提供的第一极片垂直于负极集流体厚度方向的截面结构示意图；
图13为本申请实施例提供的第二极片垂直于负极集流体厚度方向的截面结构示意图；
图14为经3D显微镜测得的本申请实施例提供的第一极片表面形貌图；
图15为本申请实施例提供的第一极片的制造过程中锂带的放置结构示意图。
附图标记说明：
10-第一集流体；11-第一空箔区；20-第一功能层；21-第一凹槽；22-第一端部覆盖区；23-第二端部覆盖区；30-第一区域；40-第二区域；60-过渡区；80-锂带；81-第一胶层；82-第二胶层；84-第四胶层；85-第三区域；86-第四区域；87-第五区域；91-第一极耳；92-第二功能层；921-第二凹槽；93-第二空箔区。
具体实施方式
为使本申请的目的、技术方案和优点更加清楚，下面将结合本申请中的附图，对本申请中的技术方案进行清楚、完整地描述，显然，所描述的实施例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。
采用硅氧负极材料加工的极片虽然有理想的比容量，但是，从正极脱出的锂离子会嵌入硅氧负极材料中，并优先与硅氧发生反应生成非活性物质如锂硅酸盐和锂硅合金，硅颗粒破裂，导致固体电解质界面(solidelectroly teinterface，简称SEI)膜反复生长-破裂-修复，使得SEI膜在生长过程中大量累计，消耗锂源，容量衰减，首效低，循环差。
鉴于上述背景，本申请提供的极片及电池，通过在第一功能层20的表面间隔分布有若干个第一区域30和若干个第二区域40，在第一区域30内，第一功能层20中的氧元素与硅元素的含量占比大于4：1，这样确保容易生成锂硅酸盐，可以降低循环过程中的电池膨胀率。SEI膜在形成过程中，提前消耗正极部分的锂离子，导致电池首效低，利用补充的金属锂形成SEI膜，减少正极锂离子的损失，从而提高锂离子的利用率，达到改善电池的首次效率的效果。
下面参考附图描述本申请提供的一种极片及电池。
参考图1所示，本申请提供一种极片，包括：第一集流体10和设置在第一集流体10至少一面的第一功能层20，第一功能层20的表面间隔分布有若干个第一区域30和若干个第二区域40；在第一区域30内，第一功能层20中的氧元素与硅元素的含量占比大于4：1；第一区域30包括锂元素。
本申请提供的极片，第一功能层20为活性材料层，通过在第一功能层20的表面间隔分布有若干个第一区域30和若干个第二区域40，第一区域30用于补充锂材料，在第一区域30内，第一功能层20中的氧元素与硅元素的含量占比大于4：1，这样确保容易生成锂硅酸盐，可以降低循环过程中的电池膨胀率。
电解液浸润一般来说依靠毛细作用，本申请提供一种极片，采用第二区域40与第一区域30相间分布的结构，电解液可以通过第二区域40渗入从而将极片浸润，减少了极片 浸润的阻碍，有利于极片均匀的浸润，提高电池浸润效果，从而提升电池的循环寿命。
第一区域30内具有碳元素、氧元素、氟元素、磷元素和硅元素；第二区域40内具有碳元素、氧元素、氟元素、磷元素和硅元素。
在第一区域30内，第一功能层20中的氟元素与磷元素的含量占比大于7：1，使得形成富含LiF惰性物质的SEI膜，提高SEI膜的稳定性，从而提高电池充放电循环稳定性。本申请通过提前给极片补充锂材料，使得本申请提供的极片加工的电池在首次充放电的过程中，充分利用补充的金属锂形成SEI膜，减少正积极锂源的损失，从而提高锂离子的利用率，达到改善电池的首次循环效率的效果。
在一种可能实施的方式中，在第一区域30内，氧元素与硅元素的含量占比可以是4：1，也可以是5：1，也可以是6：1，也可以是7：1。
容易理解的是，如果在第一区域30内，氧元素与硅元素的含量占比大于4：1，例如，氧元素与硅元素的含量占比为5：1过多的氧元素会与补入的锂离子发生化学反应，生成氧化锂或碳酸锂，会降低锂离子的利用率。
在一种可能实施的方式中，第一功能层20的表面通过设置锂材料层形成第一区域30，锂材料层中含有的锂的面密度为0.09mg/cm2～0.5mg/cm2。锂材料层可以是通过轧制设置于第一功能层20的表面，形成第一区域30。锂材料层可以是锂箔，金属锂的面密度为0.09mg/cm2～0.5mg/cm2，第一功能层20包括石墨和硅材料，其中硅材料的质量占活性材料颗粒的总质量的7％～50％，这样使得金属锂的量与硅材料的量相适配。锂材料层可以是多个锂带。
第一功能层20包括活性材料颗粒。
在一种可能实施的方式中，活性材料颗粒包括硅材料和硅氧材料中的至少一种以及碳材料，其中硅材料和/或硅氧材料的质量占活性材料颗粒的总质量的7％～50％，相应的，第一区域30含有的金属锂的面密度为0.09mg/cm2～0.5mg/cm2，这样使得金属锂的量与硅材料和/或硅氧材料的量相适配。
在一种可能实施的方式中，活性材料颗粒包括碳材料和石墨。
在一种可能实施的方式中，金属锂的面密度为0.09mg/cm2～0.5mg/cm2，活性材料颗粒包括硅材料和硅氧材料中的至少一种以及碳材料，其中硅材料和/或硅氧材料的质量占活性材料颗粒总质量的7％～50％。
在一种可能实施的方式中，参考图1所示，本申请提供的一种极片为负极片，第一集流体10可以采用铜箔、钛箔、镍网、不锈钢箔、锂铜合金薄膜或碳布。
在一种可能实施的方式中，第一集流体10的两面都设置有第一功能层20。
在第一区域30内，第一功能层20中的氟元素与磷元素的含量占比大于7：1，通过在加工极片的过程中，使得第一区域30内的第一功能层20提前与锂离子接触发生钝化反应，形成富含LiF惰性物质的钝化层，钝化层即SEI膜，这样加工的电池在化成时，形成富含LiF惰性物质的SEI膜，提高SEI膜的稳定性，从而提高电池循环的稳定性。本申请 通过提前给极片补充锂材料，使得本申请提供的极片加工的电池在首次充放电的过程中，充分利用补充的金属锂形成SEI膜，减少正积极锂源的损失，从而提高锂离子的利用率，达到改善电池的首次循环效率的效果。
考虑到电解液为六氟磷酸锂，第一区域30的氟元素和磷元素的含量占比大于7：1，多出的氟元素会与锂离子发生化学反应生成富含LiF惰性物质的SEI膜，提高SEI膜的稳定性，从而提高电池循环的稳定性。SEI膜在形成过程中，提前消耗了补充的锂形成SEI膜，减少正极锂的消耗，从而提高充放电效率。
参考图2所示为采用扫描电子显微镜(scanning electron microscope，简称SEM)进行拍摄并放大50x-5.0kx进行拍摄第一区域30与第二区域40获取的图，可以看到第一区域30与第二区域40。第二区域40用于使得相邻的第一区域30之间存在着相互间隔的区域，第二区域40是极片浸润的通道，有利于提高极片的浸润效果。
可以是采用异步轧制技术制备超薄金属锂带，在超薄金属锂带表面形成与第一区域30对应的含金属锂的区域以及与第二区域40对应的不含有金属锂的区域，通过将金属锂带中的锂离子转接到第一区域30，从而在第一功能层20的表面形成第一区域30，而与不含有金属锂的区域对应的是第二区域40。
在一种可能实施的方式中，参考图2所示，为了满足补锂面密度的要求和浸润均匀性的要求，第一区域30的宽度为100μm～4mm，即相邻的两个第二区域40之间的间距为100μm～4mm。
在一种可能实施的方式中，相邻的两个第二区域40之间的间距可以为100μm、1mm、2mm、3mm或4mm。
在一种可能实施的方式中，为了满足补锂面密度的要求和浸润均匀性要求，第二区域40的宽度为0μm～4mm，即相邻的两个第一区域30之间的间距为0μm～4mm。
本申请提供一种极片，通过使得第二区域40和第一区域30相间分布，并且通过限定第二区域40和第一区域30的宽度，有利于达到补锂面密度的要求，以及提高极片浸润电解液的均匀性。
在一种可能实施的方式中，相邻的两个第一区域30之间的间距可以为10μm、1mm、2mm、3mm或4mm。
锂离子局部嵌入位于第一区域30的硅颗粒后，会因为浓度差和电势差，向非嵌入锂离子的区域迁移，从而在第一区域30与第二区域40之间形成过渡区60，以及使得第一区域30内部锂离子均匀分布，由此达到嵌锂状态一致的效果，避免由于局部锂离子过高而发生析锂、紫斑的问题，从而提高整体嵌锂均匀的程度。
为了降低电池在循环过程中的膨胀率，对极片进行工艺补锂，第一区域30金属锂与硅反应生成锂硅酸盐作为一种缓冲层，缓解电池在循环过程中的膨胀，位于第一区域30的第一功能层20中的氧元素与硅元素的含量占比＞4:1；在第二区域40内，第一功能层20中的氧元素与硅元素的含量占比S1：S2满足：2：1≤S1：S2≤4:1，同时氧位于第一区 域30的第一功能层20中的氧元素的含量大于位于第二区域40的第一功能层20中的氧元素的含量。
为了防止硅颗粒在嵌锂过程中发生破裂，SEI膜反复生长-破裂-修复，使的SEI膜在生长过程中大量累计，消耗锂离子，造成电池容量衰减，首效低，循环差，构造富含LiF惰性物质的SEI膜，提高SEI膜的稳定性，从而提高硅负极材料的循环稳定性，位于第一区域30的第一功能层20中氟元素和磷元素含量占比＞7:1，在第二区域40内，第一功能层20中的氟元素和磷元素的含量占比S3：S4满足：6：1≤S3：S4≤7:1。同时位于第一区域30的第一功能层20中的氟元素的含量大于位于第二区域40的第一功能层20中的氟元素的含量。位于第一区域30的第一功能层20中的磷元素的含量大于位于第一区域30的第一功能层20中的磷元素的含量。
本申请还提供一种电池，包括密封壳体和位于密封壳体内部的电芯，电芯包括第一极片和第二极片，第一极片为上述的极片。
实施例一
本实施例中，第一功能层20的活性材料颗粒包括石墨和硅氧材料，硅氧材料的质量占比可以为活性材料颗粒的总质量的7％，对应的，第一区域30含有的金属锂的面密度可以为0.12，在第一区域30内，氧元素与硅元素的含量占比S1：S2为5：1，在第一区域30内，氟元素与磷元素的含量占比S3：S4为7：1。在第二区域40，氧元素与硅元素的含量占比S1：S2为4：1，在第二区域40，氟元素与磷元素的含量占比S3：S4为6：1。
实施例二
本实施例中，第一功能层20的活性材料颗粒包括石墨和硅氧材料，硅氧材料的质量占比可以为活性材料颗粒总质量的20％，对应的，第一区域30含有的金属锂的面密度可以为0.22，在第一区域30内，氧元素与硅元素的含量占比S1：S2为6：1，在第一区域30内，氟元素与磷元素的含量占比S3：S4为7.5：1。在第二区域40，氧元素与硅元素的含量占比S1：S2为4：1，在第二区域40，氟元素与磷元素的含量占比S3：S4为6：1。
实施例三
本实施例中，第一功能层20的活性材料颗粒包括石墨和硅氧材料，硅氧材料的质量占比可以为活性材料颗粒总质量的30％，对应的，第一区域30含有的金属锂的面密度可以为0.32，在第一区域30内，氧元素与硅元素的含量占比S1：S2为7：1，在第一区域30内，氟元素与磷元素的含量占比S3：S4为8：1。在第二区域40，氧元素与硅元素的含量占比S1：S2为4：1，在第二区域40，氟元素与磷元素的含量占比S3：S4为6：1。
实施例四
本实施例中，第一功能层20的活性材料颗粒包括石墨和硅氧材料，硅氧材料的质量占比可以为活性材料颗粒总质量的40％，对应的，第一区域30含有的金属锂的面密度可以为0.42，在第一区域30内，氧元素与硅元素的含量占比S1：S2为8：1，在第一区域30内，氟元素与磷元素的含量占比S3：S4为8.5：1。在第二区域40，氧元素与硅元素的 含量占比S1：S2为4：1，在第二区域40，氟元素与磷元素的含量占比S3：S4为6：1。
实施例五
本实施例中，第一功能层20的活性材料颗粒包括石墨和硅氧材料，硅氧材料的质量占比可以为活性材料颗粒总质量的50％，对应的，第一区域30含有的金属锂的面密度可以为0.5，在第一区域30内，氧元素与硅元素的含量占比S1：S2为9：1，在第一区域30内，氟元素与磷元素的含量占比S3：S4为9：1。在第二区域40，氧元素与硅元素的含量占比S1：S2为4：1，在第二区域40，氟元素与磷元素的含量占比S3：S4为6：1。
上述的实施例一至实施例五中，第一功能层20的活性材料颗粒包括石墨和硅氧材料，硅氧材料的质量占比可以为活性材料颗粒总质量的7％～50％，石墨可以是人造石墨、天然石墨或改性石墨，第一区域30含有的金属锂的面密度为0.09mg/cm2～0.5mg/cm2。这样使得金属锂的量与硅颗粒的量相适配，如果金属锂的量过大，会导致锂离子与电解液发生反应析出，降低锂离子的利用率；如果金属锂的量过小，会使得补锂效果不明显，从而使得对首次效率提高不明显。
实施例六
本实施例中，第一功能层20的活性材料颗粒包括石墨和硅氧材料，硅氧材料的质量占比可以为活性材料颗粒总质量的7％，对应的，第一区域30含有的金属锂的面密度可以为0.18在第一区域30内，氧元素与硅元素的含量占比S1：S2为6：1，在第一区域30内，氟元素与磷元素的含量占比S3：S4为7：1。在第二区域40，氧元素与硅元素的含量占比S1：S2为4：1，在第二区域40，氟元素与磷元素的含量占比S3：S4为6：1。
实施例七
本实施例中，第一功能层20的活性材料颗粒包括石墨和硅氧材料，硅氧材料的质量占比可以为活性材料颗粒总质量的30％，对应的，第一区域30含有的金属锂的面密度可以为0.28，在第一区域30内，氧元素与硅元素的含量占比S1：S2为7.5：1，在第一区域30内，氟元素与磷元素的含量占比S3：S4为8：1。在第二区域40，氧元素与硅元素的含量占比S1：S2为4：1，在第二区域40，氟元素与磷元素的含量占比S3：S4为6：1。
实施例八
本实施例中，第一功能层20的活性材料颗粒包括石墨和硅氧材料，硅氧材料的质量占比可以为活性材料颗粒总质量的50％，对应的，第一区域30含有的金属锂的面密度可以为0.34，在第一区域30内，氧元素与硅元素的含量占比S1：S2为8：1，在第一区域30内，氟元素与磷元素的含量占比S3：S4为8.5：1。在第二区域40，氧元素与硅元素的含量占比S1：S2为4：1，在第二区域40，氟元素与磷元素的含量占比S3：S4为6：1。
上述的实施例六至实施例八中，第一功能层20的活性材料颗粒包括石墨和硅氧材料，其中硅氧材料的质量占比可以为活性材料颗粒总质量的7％～50％，相应的，第一区域30含有的金属锂的面密度为0.09mg/cm2～0.5mg/cm2。这样使得金属锂的量与硅颗粒的量相适配，既避免了金属锂过量造成锂与电解液发生反应析出，降低锂离子的利用率，也避免 了金属锂的量过小，会使得补锂效果不明显、以及首次效率提高不明显。
加工时，在第一集流体10的表面涂布第一功能层20之后，置于90℃温度的干燥环境中烘烤24h，使得水分控制在300ppm以下，得到半成品极片，然后采用异步轧制技术制备超薄金属锂带，并与该半成品极片覆合制备成极片。
本申请还提供一种电池，包括密封壳体和位于密封壳体内部的电芯，电芯包括第一极片和第二极片，第一极片为上述的极片。
在一种可能实施的方式中，第二极片为正极片，第一极片为负极片。
加工时，第一极片、第二极片和隔离膜按顺序叠好，使隔离膜处于第一极片和第二极片之间，隔离膜起到隔离于第一极片和第二极片的作用，然后卷绕得到电芯，电芯置于密封壳体中，并在密封壳体内注入电解液，经过真空封装、静置、化成，以0.1C恒流充电4％荷电状态(State of Charge，简称SOC)，再以0.2C恒流充电到10％SOC、整形、容量测试等工序，获得软包锂离子电池。
在一种可能实施的方式中，密封壳体可以是铝塑膜，电解液可以是六氟磷酸锂。
在一种可能实施的方式中，第一区域30为补锂区域，第二区域40为未补锂区域，经3D显微镜测试，第一区域30较亮，第二区域40较暗(如图14所示)。
在一种可能实施的方式中，可以按照如下过程进行补锂：如图15所示，将多个锂带80间隔分布在第一功能层20表面，该多个锂带80之间存在露出第一功能层20表面的间隙C，经电池制备过程中的化成等反应后，设置锂带80的区域形成补锂区域，即第一区域30；存在于多个锂带80之间的间隙C形成未补锂区域，即第二区域40，如图14所示，第一区域30呈非连续状态，通过第二区域40，利于电解液对极片的浸润性，可提高锂带的利用率，优化极片和电池性能。
其中，在补锂过程中，可以在干燥环境中，将形成有第一功能层20的极片前体在90℃左右烘烤约24h，使其水分控制在300ppm以下，然后将锂带80置于烘烤后的极片表面，经压合等处理后，使锂带80与第一功能层20复合，以进行补锂。
上述极片可以采用涂覆法制得，其制备过程一般包括配料(配制浆料)、涂布(将浆料涂布于集流体基材的表面以形成第一功能层20)、辊压、分切(根据极片的预设大小和形状等参数进行分切)、烘烤等步骤，然后再进行补锂等后续过程。
在一种可能实施的方式中，所用锂带80可以包括长度小于第一功能层20的宽度的短条锂带(短条锂带分布方式如图15所示，其形成的极片表面形貌如图14所示)，可以将多个短条锂带沿第一功能层20的宽度方向(箭头B所示的方向)依次放置，形成一列，然后再按照该过程，沿第一功能层20的长度方向(箭头A所示的方向)形成另一列，每一列的长度可以小于或等于极片的宽度(由此形成的第一区域30排布而成的列的长度小于或等于极片的宽度)，但不局限于此，也可以将多个短条锂带不规则地分布于第一功能层20表面，或者，采用长度与第一功能层20的宽度基本相同的长条锂带间隔分布于第一功能层20表面(例如，任意两个相邻的长条锂带之间存在间隙，经化成后，该间隙形成 第二区域40)。
在一种可能实施的方式中，锂带80的用量可以满足：设置在第一功能层20表面的锂带80的总质量与第一功能层20表面(背离第一集流体10的一面)的面积之比为0.09～0.5mg：1m2。
在一种可能实施的方式中，锂带80的厚度可以为1.9μm-9μm，由于纯金属锂极高的理论比容量，如果对极片表面进行整幅补锂，金属锂厚度通常需要1μm左右，制备难度极高，一致性很差，而本申请中，采用超薄金属锂带非整面覆盖式补锂，超薄金属锂带其在第一功能层20表面呈现条纹/波纹等非连续覆盖状态，能够有效补锂，提高锂金属利用率，同时还具有制备简单、一致性较好等优点。
在一种可能实施的方式中，一般将锂锭压至厚度为微米级别后，再将得到的微米级锂带置于第一功能层20表面进行补锂。例如，在一些实施例中，将200μm～2mm的锂锭压延成厚度为1.9μm～9μm的锂带80，再将其置于第一功能层20表面进行补锂。
在一种可能实施的方式中，无机盐层可以是第一区域30内的活性物质颗粒通过补锂的锂源嵌入形成的无机盐层，亦即，构成无机盐层的材料为无机盐，无机盐层是通过在第一区域30补充的锂元素嵌入第一区域30的活性物质颗粒生成的，该无机盐层例如包括氟化锂或碳酸锂、锂硅酸盐等中的至少一种。
在一种可能实施的方式中，第一区域30和第二区域40交错设置/相间分布，亦即，第一功能层20表面分布有多个第一区域30和多个第二区域40，多个第二区域40将第一功能层20表面间隔形成多个第一区域30。
其中，多个第一区域30可以沿第一功能层20/极片的长度方向(箭头A所指示的方向)分布，亦即，多个第一区域30与多个第二区域40沿第一功能层20/极片的长度方向依次交错分布。
在一种可能实施的方式中，如图11、图12和图14所示，第一区域30的延伸方向/长度方向可以与第一功能层20的宽度方向形成第一夹角，第一夹角可以为0°～60°，在一种可能实施的方式中，第一夹角可以为0°～45°，例如0°(即第一区域30的长度方向与第一功能层20的宽度方向平行)、10°、20°、30°、40°或45°等，这样，利于极片补锂和电解液浸润效果，同时不影响极片沿其长度方向进行卷绕，利于电池的制作和性能。
其中，多个第一区域30的延伸方向可以相同或不同，即其与第一功能层20的宽度方向形成的第一夹角可以相同或不同。
此外，在第一功能层20/极片的宽度方向上，最靠近第一功能层20外缘/边缘的第一区域30与第一功能层20外缘之间的距离为A，A可以为0-2mm，例如0(即该第一区域30与第一功能层20外缘齐平)、0.5mm、1mm、1.5mm、2mm等；A与第一功能层20的宽度之比可以为0～0.03，例如0、0.01、0.02、0.03等。
在一种可能实施的方式中，在第一功能层20的宽度方向上，由至少一个第一区域30形成一列，该列可以是连续状态，即该列由一个第一区域30形成(其中间不会被第二区 域40间断)，或者，该列也可以是非连续状态，即该列由多个第一区域30沿第一功能层20的宽度方向依次排布而成，其中相邻的两者之间存在第二区域40，被第二区域40间断。
此外，第一区域30沿第一功能层20的宽度方向延伸，在第一功能层20的宽度方向上，第一区域30可以基本为平直结构，或者具有弯折/弯曲等结构。
此外，在第一功能层20/极片的长度方向上，最靠近第一功能层20外缘的第一区域30与第一功能层20外缘之间的距离(即最靠近第一功能层20外缘的第二区域22在第一功能层20长度方向上的宽度)可以为0-4mm，例如100μm～4mm。
在一种可能实施的方式中，第一功能层20具有相对的第一端和第二端，第一端至第二端的方向平行于第一功能层20的长度方向，最靠近第一端的第一区域30与第一功能层20第一端边缘(第一功能层20边缘)的距离w1为100μm～4mm，例如100μm、300μm、500μm、700μm、1mm、2mm、3mm、4mm等，即在沿第一功能层20的长度的方向上，最靠近第一端的第一区域30与第一端的边缘之间存在的第二区域40的宽度为w1；最靠近第二端(第一功能层20边缘)的第一区域30与第一功能层20的第二端端缘的距离w2为0μm～4mm，例如0、100μm、300μm、500μm、700μm、1mm、2mm、3mm、4mm等。
其中，当w2＝0时，最靠近第一功能层20的第二端的第一区域30与第一功能层20的第二端的边缘之间没有第二区域(即最靠近第二端的第一区域30与第二端的边缘之间的第二区域40的宽度w2为0)，当w2不为0时(即0＜w2≤4mm)，在沿第一功能层20的长度方向上，最靠近第一功能层20的第二端的第一区域30与第二端的边缘之间存在第二区域40，该第二区域40的宽度为w2。
在一种可能实施的方式中，w1与w2可以相同或不同。
为进一步兼顾提高补锂效果以及电解液浸润性，在一些优选实施例中，多个第一区域30的总面积(即多个第一区域30的面积之和)与多个第二区域40的总面积(即多个第二区域40的面积之和)之比为0.7：1～3：1，例如0.7：1、1：1、1.5：1、2：1、2.5：1、或3：1等。
其中，可以采用显微镜捕捉第一区域30和第二区域40的轮廓，以测定多个第一区域30的总面积与多个第二区域40的总面积之比。
一般情况下，第一区域30和第二区域40之间呈现分界，以第一集流体10的表面为基准，第一区域30高于第二区域40，即在沿第一功能层20的厚度方向上，第一区域30最远离第一集流体10的部位至第一集流体10的距离a大于第二区域40最远离第一集流体10的部位至第一集流体10的距离b(a＞b)。
在一些实施例中，第一区域30最远离第一集流体10的部位与第二区域40最远离第一集流体10的部位的高度之差为0.1μm～8μm(即a-b＝0.1-8μm)，例如0.1μm、0.5μm、1μm、2μm、3μm、4μm、5μm、6μm、7μm或8μm等。
在一种可能实施的方式中，第一区域30与第二区域40的高度之差的测定方式可以包 括但不限于以下方式：(1)采用离子研磨(CP)设备对补锂极片进行溅射，得到截面，再利用扫描电子显微镜(SEM)进行拍摄，并放大至所需倍率进行拍摄，获取高度差；(2)采用3D显微镜进行放大至所需倍率进行拍摄，然后采用轮廓仪测量高度差。
在一些实施例中，第一功能层20设有第一凹槽21，第一胶层81覆盖第一凹槽21。其中，第一凹槽21可作为用于设置极耳的极耳槽，在一些实施例中，极片还包括第一极耳91和和形成在第一功能层20表面上的第一胶层81，至少部分该第一极耳91位于第一凹槽21内并被第一胶层81覆盖(即第一极耳91位于第一凹槽21内的部分被第一胶层81覆盖)，由此，可以保护极耳区，提高极片和电池的安全性，例如避免第一极耳周围的补锂区域中的锂在充放电过程中迁移至正极耳区(对应正极耳所在的极耳槽处)、以及由此导致的负极耳区的析锂问题。
在一种可能实施的方式中，第一胶层81设置在第一功能层20的表面的部分区域，即不完全覆盖第一功能层20。第一胶层81覆盖至少一个第一区域30。
在一种可能实施的方式中，第一凹槽21底面的至少部分区域为第一集流体10表面，即第一凹槽21底面的部分区域露出第一集流体10，第一极耳91可以与第一凹槽21底面露出的第一集流体10连接，具体可以是焊接在第一凹槽21底面露出的第一集流体10上。
其中，极片可以是极耳中置结构(CPT)，即极耳设置在极片的中部，而非端部。
在一种可能实施的方式中，第一凹槽21的至少两侧为第一功能层20。在一些实施例中，在垂直于第一集流体10的厚度方向的平面上，第一凹槽21的一侧与第一集流体10的一个长边持平，其余侧被第一功能层20围绕，即第一凹槽21具有朝向第一集流体10的一个长边的开口，设置第一极耳91后，第一极耳91的一端可以通过该开口伸出第一集流体10的外缘，具体可以是第一极耳91沿其长度方向通过该开口伸出第一集流体10的外缘，第一极耳91位于第一凹槽21内的部分(即未伸出第一集流体10的外缘的部分)被第一胶层81覆盖(如图12所示)。
其中，第一极耳91的长度方向与第一区域30/第二区域40的长度方向平行(即第一耳200与第一区域30/第二区域40的延伸方向一致)。
如图11所示，第一凹槽21在第一集流体10上的投影为长方形，其一个短边与第一集流体10的一个长边持平，其余三个边被第一功能层20围绕。
在一种可能实施的方式中，第一凹槽21具有相对的第一侧和第二侧、以及相对的第三侧和第四侧，第三侧/第四侧位于第一侧与第二侧之间(第三侧/第四侧连接第一侧和第二侧)，第一侧至第二侧的方向平行于沿第一区域至第二区域的方向。
示例性地，在图11和图12中，第一侧为左侧，第二侧为右侧，第三侧为下侧，第四侧为上侧，第一凹槽21的左侧、右侧、下侧均被第一功能层20围绕，上侧没有第一功能层20(即第一凹槽21的上侧与第一功能层20的边缘持平)。第一侧至第二侧的方向平行于第一功能层20的长度方向，第三侧至第四侧的方向平行于第一功能层20的宽度方向。
其中，第一胶层81延伸至第一凹槽21周边的第一功能层20表面，第一胶层81位于 第一凹槽21第一侧的第一功能层20表面的部分覆盖a1个第一区域30，a1为0～8，例如0、1、2、3、4、5、6、7、8等，即位于第一凹槽21第一侧且与第一胶层81接触的第一区域的数量为a1个，亦即，第一功能层20表面包括位于第一凹槽21第一侧且被第一胶层81覆盖的第三区域85，延伸至第三区域85内的第一区域30的数量为a1个。
示例性地，如图11所示，a1＝1。
此外，第一胶层81位于第一凹槽21第二侧的第一功能层20表面的部分覆盖a2个第一区域30，a2为0～8，即位于第一凹槽21第二侧且与第一胶层81接触的第一区域30的数量为a2个，亦即，第一功能层20表面包括位于第一凹槽21第二侧且被第一胶层81覆盖的第四区域86，延伸至第四区域86内的第一区域30的数量为a2个。
示例性地，如图11所示，a2＝1。
此外，第一胶层81位于第一凹槽21第三侧的第一功能层20表面的部分与a3个第一区域30接触，a3为0～40，例如0、2、5、8、10、12、15、18、20、22、25、28、30、32、35、38、40等，即位于第一凹槽21第三侧且与第一胶层81接触的第一区域30的数量为a3个，亦即，第一功能层20表面包括位于第一凹槽21第三侧且被第一胶层81覆盖的第五区域87，延伸至第五区域87内的第一区域30的数量为a3个。
如图11和图12所示，a3亦为与第一胶层81接触的第一区域30的总数量。
在一种可能实施的方式中，延伸至第三区域85内的第一区域30(a1个)均延伸至第五区域87内，延伸至第四区域86内的第一区域30(a2个)均延伸至第五区域87内，延伸至第五区域87内且与第一凹槽21相接的第一区域30的数量为a4个，a3＝a1+a2+a4。
示例性地，如图11所示，a3＝4，其中，a1＝1，a2＝1，a4＝2。
在一种可能实施的方式中，第一胶层81位于第一凹槽21的第一侧的第一功能层20表面的部分在沿第一功能层20长度方向上的宽度w31(亦为第三区域85在沿第一功能层20长度方向上的宽度)为1mm～5mm，例如1mm、1.5mm、2mm、2.5mm、3mm、3.5mm、4mm、4.5mm、5mm等。
此外，第一胶层81位于第一凹槽21的第二侧的第一功能层20表面的部分在沿第一功能层20长度方向上的宽度w32(亦为第四区域86在沿第一功能层20长度方向上的宽度)为1mm～5mm，例如1mm、1.5mm、2mm、2.5mm、3mm、3.5mm、4mm、4.5mm、5mm等。
其中，w31与w32可以相同或不同。第一胶层81在沿第一功能层20长度方向上的总宽度基本等于w31、第一凹槽21在沿第一功能层20长度方向上的宽度、w32之和。
在一种可能实施的方式中，第一区域30的相对两端的端缘分别与第一功能层20的相对两侧的边缘持平，如图11和图12所示，任一第一区域30在第一功能层20的宽度方向上的长度等于其所在的第一功能层20的长度，例如，位于第一凹槽21的相对两侧(第一侧和第二侧)的第一区域30的长度等于第一功能层20位于第一凹槽21的相对两侧的部分的宽度。
第一功能层20的长度方向亦为第一集流体10的长度方向，第一功能层20的宽度方向亦为第一集流体10的宽度方向，第一集流体10的宽度基本等于第一功能层20的最大宽度(即图11和图12中的第一功能层20位于第一凹槽21的相对两侧的部分的宽度)。
在一种可能实施的方式中，如图11所示，第一集流体10的至少一端部还可以设有未设置第一功能层20的第一空箔区11。
本申请的实施例还提供一种电池，包括依次层叠设置的第一极片、隔膜和极性与第一极片相反的第二极片，第一极片包括上述的极片。
在一种可能实施的方式中，该电池包括电芯，电芯包括依次层叠设置的第一极片、隔膜和第二极片，该电芯具体可以是由第一极片、隔膜和第二极片依次层叠设置后卷绕而成的卷绕式电芯，其中，可以沿第一极片/隔膜/第二极片的长度方向进行卷绕，形成卷绕式电芯，在卷绕式电芯中，第一极片、隔膜、第二极片均分别有弯折部、以及连接于每个弯折部两端的直部，一个弯折部至另一个弯折部的方向平行于卷绕式电芯的长度方向，一个直部至另一个直部的方向平行于卷绕式电芯的宽度方向。
其中，隔膜起隔离作用，用于间隔第一极片和第二极片，防止二者接触短路，隔膜的厚度可以为5～16μm，例如5μm、8μm、10μm、13μm、16μm等，该隔膜可以是本领域常规隔膜，例如包括基材或在基材上涂布涂层的涂覆隔膜。
在一种可能实施的方式中，第二极片包括第二集流体、以及设于第二集流体表面的第二功能层92，第二极片具有相对的两端(分别记为第五端和第六端)，其至少一端存在未设置涂层的第二空箔区93，除该第二空箔区93外，第二极片的其余部分设有第二功能层92。第二功能层92与第二空箔区93相接的部分通常存在凹凸不平的结构，为避免损伤隔膜，提高电池的安全性能，可以在第二极片的至少一端的被第一极片覆盖的部分设置第二胶层82，其中，第二极片被第一极片覆盖的部分通常亦为第二极片被隔膜覆盖的部分。第二功能层92为第二极片的活性材料层。
如图13所示，第二极片的一端(第五端)被第一极片覆盖的区域设有第二胶层82，第二胶层82对应的第一极片的第一区域30的数量为x个，0≤x≤20，x例如为0、1、2、3、4、5、6、7、8、9、10、11、12、13、14、15、16、17、18、19或20。
在一种可能实施的方式中，如图11和图12所示，第一极片具有相对的两端(分别记为第三端和第四端)，其一端(第三端)具有第一端部覆盖区22，第一端部覆盖区22与第二极片的第二胶层82位置对应，即第一端部覆盖区22与第二胶层82相互覆盖(第二胶层82在第一极片上的投影与第一端部覆盖区22基本重合)，第一端部覆盖区22在第一极片/第二极片的长度方向上的宽度W4等于第二胶层82在第一极片/第二极片的长度方向上的宽度W6，第一端部覆盖区22内存在x个第一区域30。
在一些实施例中，第二胶层82在第二极片的长度方向上的宽度w6为3mm～5mm，例如w6为3mm、3.5mm、4mm、4.5mm或5mm等。
其中，如图13所示，第二胶层82覆盖至少部分第二空箔区93、并从第二空箔区93 延伸至第二功能层92的表面。
此外，如图11至图13所示，第一极片的另一端(第四端)具有覆盖第二极片另一端(第六端)的第二端部覆盖区23，即第二极片的第六端在第一极片上的投影位于第二端部覆盖区23，不超出第二端部覆盖区23，第二极片的第六端不存在空箔区(即第二功能层92与第二集流体的外缘齐平)，可以不设置第二胶层82。
在一些实施例中，第二端部覆盖区23在第一极片的长度方向上的宽度w5为3～5mm，例如3mm、3.5mm、4mm、4.5mm、5mm等。
如图13所示，第二极片表面设有与第一极片的第一极耳91/第一凹槽21位置对应的第三胶层，第三胶层在第一极片上的投影可以覆盖第一凹槽21，进一步防止负极析锂。
其中，第三胶层在第一极片上的第一投影覆盖至少一个第一区域30，且满足：第一投影位于第一凹槽21第一侧的部分覆盖0～8个第一区域30，例如0、1、2、3、4、5、6、7、8等，可以等于或不等于a1；第一投影位于第一凹槽21第二侧的部分覆盖0～8个第一区域30，例如0、1、2、3、4、5、6、7、8等，可以等于或不等于a2；第一投影位于第一凹槽21第三侧的部分覆盖0～40个第一区域30，例如0、2、5、8、10、12、15、18、20、22、25、28、30、32、35、38、40等，可以等于或不等于a3。
在一种可能实施的方式中，第一投影位于第一凹槽21的第一侧的部分在沿第一功能层20长度方向上的宽度可以为1mm～5mm，例如1mm、1.5mm、2mm、2.5mm、3mm、3.5mm、4mm、4.5mm、5mm等，可以等于或不等于w31；第一投影位于第一凹槽21的第二侧的部分在沿第一功能层20长度方向上的宽度可以为3mm～5mm，例如1mm、1.5mm、2mm、2.5mm、3mm、3.5mm、4mm、4.5mm、5mm等，可以等于或不等于w32。
在一种可能实施的方式中，第三胶层在第一极片上的第一投影可以覆盖第一胶层81、或者被第一胶层81覆盖，二者例如重合。
在一种可能实施的方式中，第二极片设有第二极耳，在电芯的宽度方向上，第一极耳91与第二极耳不重叠，即第一极耳91垂直于电芯的宽度方向的投影与第二极耳垂直于电芯的宽度方向的投影不重叠。
在一些实施例中，第二功能层92设有第二凹槽921、以及覆盖第二凹槽921的第四胶层84，第二极耳至少部分位于第二凹槽921内并被第四胶层84覆盖(即第二极耳位于第二凹槽921内的部分被第二胶层82覆盖)。
在一种可能实施的方式中，第二凹槽921作为用于设置极耳的极耳槽，其底面的至少部分区域为第二集流体表面(即其底面的部分区域露出第二集流体)，第二极耳可以与第二凹槽921底面露出的第二集流体连接，具体可以是焊接在第二凹槽921底面露出的第二集流体上。
其中，如图13所示，第二极片可以是极耳中置结构，即第二极耳设置在第二极片的中部，而非端部。
在一种可能实施的方式中，第二凹槽921的至少两侧为第二功能层92。在一些实施例中，如图13所示，在垂直于第二集流体的厚度方向的平面上，第二凹槽921的一侧与第二集流体的一个长边持平，其余侧被第二功能层92围绕，即第二凹槽921具有朝向第二集流体的一个长边的开口，设置第二极耳后，第二极耳的一端可以通过该开口伸出第二集流体的外缘，具体可以是第二极耳沿其长度方向通过该开口伸出第二集流体的外缘，第二极耳位于第二凹槽921内的部分(即未伸出第一集流体10的外缘的部分)被第二胶层82覆盖。其中，第二极耳的长度方向与第二极片的宽度方向平行。
如图13所示，第二凹槽921在第二集流体上的投影为长方形，其一个短边与第二集流体的一个长边持平，其余三个边被第二功能层围绕。
在一种可能实施的方式中，第四胶层84延伸至第二凹槽921周边的第二功能层92表面，与第二凹槽921周边的第二功能层92粘接。
在一种可能实施的方式中，第二凹槽921具有第四侧、第五侧和第六侧，沿第四侧至第五侧的方向平行于第二极片的长度方向，第四胶层84在第一极片上的投影覆盖至少一个第一区域30，且满足：第四胶层84位于第二凹槽第四侧的部分在第一极片上的投影覆盖0～8个第一区域30，例如0、1、2、3、4、5、6、7或8等，可以等于或不等于a1；第四胶层84位于第二凹槽第五侧的部分在第一极片上的投影覆盖0～8个第一区域30，例如0、1、2、3、4、5、6、7或8等，可以等于或不等于a2；第四胶层84位于第二凹槽第六侧的部分在第一极片上的投影覆盖0～40个第一区域30，例如0、2、5、8、10、12、15、18、20、22、25、28、30、32、35、38或40等，可以等于或不等于a3。
在一种可能实施的方式中，第四胶层84位于第二凹槽第四侧的部分在沿第二极片长度方向上的宽度可以为1mm～5mm，例如1mm、1.5mm、2mm、2.5mm、3mm、3.5mm、4mm、4.5mm或5mm等，可以等于或不等于w31；第四胶层84位于第二凹槽第五侧的部分在沿第二极片长度方向上的宽度可以为3mm～5mm，例如1mm、1.5mm、2mm、2.5mm、3mm、3.5mm、4mm、4.5mm或5mm等，可以等于或不等于w32。
在一种可能实施的方式中，第二凹槽921的形状、尺寸等参数可以与第一凹槽21相同或不同，第四胶层84的形状、面积等参数可以与第一胶层81相同或不同。
上述第一胶层81、第二胶层82、第三胶层、第四胶层84的厚度分别可以为10～16μm，例如10μm、11μm、12μm、13μm、14μm、15μm、16μm等，其具体可以是胶纸。
需要说明的是，如上述的某一胶层(或其投影)覆盖第一区域30是指，在第一功能层20的长度方向上，被该胶层覆盖的第一区域30的相对两侧均位于该胶层在第一功能层20表面上的投影内(即被该胶层覆盖的第一区域30不伸出该胶层在第一功能层20表面上的投影的外缘)，而在第一功能层20的宽度方向上，被该胶层覆盖的第一区域30可以部分位于该胶层在第一功能层20表面上的投影内、部分位于该胶层在第一功能层20表面上的投影之外、或者全部位于该胶层在第一功能层20表面上的投影内。
示例性地，如图11和图12所示，第一胶层81覆盖4个第一区域30，在第一功能层 20的长度方向向，该4个第一区域30的相对两侧均位于第一胶层81在第一功能层20表面上的投影内，而在第一功能层20的宽度方向上，该4个第一区域30部分延伸至第一胶层81在第一功能层20表面上的投影内，而部分位于第一胶层81在第一功能层20表面上的投影之外。
上述电池可以包括锂离子电池，其可以通过本领域常规方法制得，制备过程一般包括卷绕、封装、注液、陈化、化成、二封、分选、包装等步骤。例如，可以将第一极片、隔膜、第二极片层叠放置后，卷绕形成裸电芯，将裸电芯置于外包装箔(如铝塑膜)中，然后向电芯中注入电解液，再经过真空封装、静置、化成(如0.1C恒流充电4％SOC(荷电状态)，再以0.2C恒流充电到10％SOC)、整形等工序，制成软包锂离子电池。
为了说明本申请提供的一种极片，通过改进，可以实现在提高电池的首次效率的同时，实现改善电池膨胀效果，对生产的极片进行以下测试：
测试一、对第一区域30和第二区域40的表面形貌测试
采用扫描电子显微镜(SEM)进行拍摄并放大500x-1.0kx进行拍摄获，参考图2图所示为放大50x的SEM图，采用标尺定位测试第一区域30与第二区域40的宽度。
此处列举对相邻的第二区域40之间的间距，即第一区域30的宽度，列举图中H1、H2、以及H3处的测量值，其中H1＝537μm，H2＝372μm，H3＝416μm。
此处列举对相邻的第一区域30之间的间距，即第二区域40的宽度，列举图中H4、以及H5处的测量值，其中H4＝267μm，H5＝279μm。
测试二、对第一区域30和第二区域40的元素进行测试
在此，选取本申请实施例提供的一种极片，将SEM采集图片的位置采用X射线能谱仪(Energy Dispersive Spectrometer，简称EDS)进行测试分析，参考图3所示，为500倍电镜图的EDS面扫图，参考图4所示，为图3中虚线框内的虚线位置500倍电镜图的面扫EDS图。
对参考图5所示的横线AB表示从第一区域30延伸到第二区域40的直线路径位置，采用X射线能谱仪(EDS)进行测试图5中横线AB位置的元素分布。其测量的SEM元素含量线扫描图参考图6、图7和图8所示。
图6表示磷元素的分布趋势图，横坐标都表示位置，纵坐标表示磷元素的含量，从图6中可以看出，从第一区域30到第二区域40，磷元素的含量减少。
图7表示氟元素的分布趋势图，横坐标都表示位置，纵坐标表示氟元素含量，从图7中可以看出，从第一区域30到第二区域40，氟元素的含量减少。
图8表示氧元素的分布趋势图，横坐标都表示位置，纵坐标表示氧元素的含量，从图8中可以看出，从第一区域30到第二区域40，氧元素的含量减少。
测试三、循环测试和膨胀测试
下面通过分别对两个对比组和两个实验组的电池进行循环测试和膨胀测试，该两个对 比组选用的电池与该两个实验组选用的电池的差异仅在于，该两个实验组选用的电池采用本申请提供的极片为负极片，而对比组选用的电池采用常规的负极片，不含有金属锂。
测试过程包括以下步骤：
步骤1、将电池在5℃±2℃的温度环境下静置10min；
步骤2、以0.2C的电池放电速率放电至下限电压，并静置10min；
步骤3、以0.7C的电池充电速率充电至上限电压，截止0.05C，静置10min；
步骤4、以0.2C的电池放电速率放电至下限电压，再做初始容量测试；
步骤5、将电池静置10min；
步骤6、以3C的电池充电速率充电至上限电压，截止0.05C，再测试电池的厚度；
步骤7、将电池在25℃±2℃的温度环境下静置10min；
步骤8、以1C的电池放电速率放电至下限电压，并静置10min；
步骤9、以3C的电池充电速率充电至上限电压，截止0.05C，静置10min；
步骤9、将步骤8和步骤9循环进行1000次，其中在0～200次循环中，每满50次循环之后，在满电状态下测试电池的厚度，在200～1000次循环中，每满100次循环之后，在满电状态下测试电池的厚度，并且在25℃的温度环境下，再重复步骤3和步骤4做容量测试，在1000次循环完成之后，在满电状态下检测电池的厚度。
测试四、容量测试
以相同的目标容量的电池，不同的补锂面密度分别加工出目标容量不同的四个实验组电池和一个对比组电池，将这些电池置入25℃的恒温环境下，采用1C的电池充电速率，以恒流恒压充电至4.48V，然后恒压至0.05C截止，静置5min，然后采用0.2C的电池放电速率放电至3V，并且以3V的容量数据进行对比，其结果参照下表1-4所示：
表1
表2
表3
表4

通过表1至表4得知，从表1至表4都可以直观的得到，实验组的电池首次效率均比相应的对比组电池的首次效率提升，说明了本申请可以明显改善锂离子电池首次效率低的问题。
实验组1至实验组4，相对于对比组1，其3V的容量明显提升，各个不同目标容量电池中，其极片的第一区域30采用不同面密度的金属锂，电池容量均有提升，且达到目标容量值。
步骤9的检测结果参照图10所示，从图10可以看出，横坐标表示充放电循环次数，纵坐标表示膨胀率，本专利提供的电池，在满电状态下的膨胀率低于现有的电池，对电池的膨胀改善效果明显。
参考图9所示为本申请提供的电池和现有的电池的循环性能曲线对比图，横坐标表示充放电循环次数，纵坐标表示电池的容量保持率，从图9可以看出，本专利提供的电池，在完成450次充放电循环，电池的容量降低到80％，现有的电池在完成350次充放电循环之后，电池的容量降低为80％，因而，本专利提供的电池，电池循环性能提升约100次充放电循环，相应的电池的容量保持率提升约5％～15％。由此说明，本专利通过改进，对电池的容量提升效果明显，并且电池的循环性能的提升效果也明显。
在本申请的描述中，需要理解的是，所使用的术语“中心”、“长度”、“宽度”、“厚度”、“顶端”、“底端”、“上”、“下”、“左”、“右”、“前”、“后”、“竖直”、“水平”、“内”、“外”“轴向”、“周向”等指示方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的位置或原件必须具有特定的方位、以特定的构造和操作，因此不能理解为对本申请的限制。
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个该特征。在本申请的描述中，“多个”的含义是至少两个，例如两个、三个等，除非另有明确具体的限定。

Claims (18)

  1. 一种极片，其特征在于，包括：第一集流体(10)和设置在所述第一集流体(10)至少一面的第一功能层(20)，所述第一功能层(20)的表面间隔分布有若干个第一区域(30)和若干个第二区域(40)；
    在所述第一区域(30)内，所述第一功能层(20)中的氧元素与硅元素的含量占比大于4：1。
  2. 根据权利要求1所述的极片，其特征在于，所述第一区域(30)内具有碳元素、氧元素、氟元素、磷元素和硅元素。
  3. 根据权利要求2所述的极片，其特征在于，在所述第一区域(30)内，所述第一功能层(20)中的氟元素与磷元素的含量占比大于7：1。
  4. 根据权利要求1所述的极片，其特征在于，所述第二区域(40)内具有碳元素、氧元素、氟元素、磷元素和硅元素。
  5. 根据权利要求4所述的极片，其特征在于，在所述第二区域(40)内，所述第一功能层(20)中的氧元素与硅元素的含量占比S1：S2满足：2：1≤S1：S2≤4:1。
  6. 根据权利要求5所述的极片，其特征在于，在所述第二区域(40)内，所述第一功能层(20)中的氟元素和磷元素的含量占比S3：S4满足：6：1≤S3：S4≤7:1。
  7. 根据权利要求1-6任一所述的极片，其特征在于，位于所述第一区域(30)的所述第一功能层(20)中的氟元素的含量大于位于所述第二区域(40)的所述第一功能层(20)中的氟元素的含量。
  8. 根据权利要求1-6任一所述的极片，其特征在于，位于所述第一区域(30)的所述第一功能层(20)中的磷元素的含量大于位于所述第一区域(30)的所述第一功能层(20)中的磷元素的含量。
  9. 根据权利要求1-6任一所述的极片，其特征在于，位于所述第一区域(30)的所述第一功能层(20)中的氧元素的含量大于位于所述第二区域(40)的所述第一功能层(20)中的氧元素的含量。
  10. 根据权利要求1-6任一所述的极片，其特征在于，所述第二区域(40)的宽度为0μm～4mm；和/或
    所述第一区域(30)的宽度为100μm～4mm。
  11. 根据权利要求1-6任一所述的极片，其特征在于，所述第一功能层(20)包括活性材料颗粒；
    所述活性材料颗粒包括硅材料和硅氧材料中的至少一种以及碳材料，其中硅材料和/或硅氧材料的质量占所述活性材料颗粒的总质量的7％～50％；或
    所述活性材料颗粒包括碳材料和石墨；或
    所述活性材料颗粒包括硅材料和硅氧材料中的至少一种以及碳材料，其中硅材料和/或硅氧材料的质量占所述活性材料颗粒的总质量的7％～50％。
  12. 根据权利要求1所述的极片，其特征在于，所述第一区域(30)的延伸方向与所述第一功能层(20)的宽度方向形成第一夹角，所述第一夹角的范围为0°～45°；和/或，
    多个所述第一区域(30)的总面积与所述第二区域(40)的总面积之比为0.7：1～3：1；和/或，
    以所述第一集流体(10)的表面为基准，所述第一区域(30)最远离所述第一集流体(10)的部位高于所述第二区域(40)，所述第一区域(30)最远离所述第一集流体(10)的部位与所述第二区域(40)最远离所述第一集流体(10)的部位的高度之差为0.1μm～8μm。
  13. 根据权利要求12所述的极片，其特征在于，所述极片还包括第一极耳(91)和形成在所述第一功能层(20)表面上的第一胶层(81)，所述第一功能层(20)设有第一凹槽(21)，至少部分所述第一极耳(91)位于所述第一凹槽(21)内并被所述第一胶层(81)覆盖，且所述第一胶层(81)覆盖至少一个所述第一区域(30)。
  14. 根据权利要求13所述的极片，其特征在于，所述第一凹槽(21)具有第一侧、第二侧和第三侧，沿所述第一侧至所述第二侧的方向平行于所述第一功能层(20)的长度方向；其中，
    所述第一胶层(81)位于所述第一凹槽(21)第一侧的所述第一功能层(20)表面的部分覆盖0～8个所述第一区域(30)；和/或，
    所述第一胶层(81)位于所述第一凹槽(21)第二侧的所述第一功能层(20)表面的部分覆盖0～8个所述第一区域(30)；和/或，
    所述第一胶层(81)位于所述第一凹槽(21)第三侧的所述第一功能层(20)表面的部分覆盖0～40个所述第一区域(30)；和/或，
    所述第一胶层(81)位于所述第一凹槽(21)第一侧的所述第一功能层(20)表面的部分在所述第一功能层(20)的长度方向上的宽度为1mm～5mm；和/或，
    所述第一胶层(81)位于所述第一凹槽(21)第二侧的所述第一功能层(20)表面的部分在所述第一功能层(20)的长度方向上的宽度为1mm～5mm。
  15. 一种电池，其特征在于，包括密封壳体和位于所述密封壳体内部的电芯，所述电芯包括第一极片和第二极片，所述第一极片为权利要求1-14任一项所述的极片，所述第二极片的极性与所述第一极片的极性相反。
  16. 根据权利要求15所述的电池，其特征在于，所述第二极片的一端被所述第一极片覆盖的区域设有第二胶层(82)；其中，所述第二胶层(82)对应的第一极片的所述第一区域(30)的数量为0～20个；和/或，
    所述第二极片包括第二集流体、以及设于所述第二集流体表面的第二功能层(92)， 所述第二极片的一端存在未设置所述第二功能层(92)的第二空箔区(93)，所述第二胶层(82)覆盖至少部分所述第二空箔区(93)、并从所述第二空箔区(93)延伸至所述第二功能层(92)的表面；和/或，
    所述第二胶层(82)在所述第二极片的长度方向上的宽度为3mm～5mm。
  17. 根据权利要求16所述的电池，其特征在于，所述第一功能层(20)设有第一凹槽(21)，所述第二极片表面设有与所述第一凹槽(21)的位置对应的第三胶层；和/或，
    所述第二极片包括第二集流体、以及设于所述第二集流体表面的第二功能层(92)，所述第二功能层(92)设有第二凹槽(921)、以及覆盖所述第二凹槽(921)的第四胶层(84)，所述第二极片设有第二极耳，所述第二极耳至少部分位于所述第二凹槽(921)内并被所述第四胶层(84)覆盖。
  18. 根据权利要求17所述的电池，其特征在于，所述第一凹槽(21)具有第一侧、第二侧和第三侧，所述第三胶层在所述第一极片上的第一投影覆盖至少一个所述第一区域(30)，且满足：所述第一投影位于所述第一凹槽(21)第一侧的部分覆盖0～8个所述第一区域(30)；和/或，
    所述第一投影位于所述第一凹槽(21)第二侧的部分覆盖0～8个所述第一区域(30)；和/或，
    所述第一投影位于所述第一凹槽(21)第三侧的部分覆盖0～40个所述第一区域(30)；和/或，
    所述第二凹槽(921)具有第四侧、第五侧和第六侧，所述第四胶层(84)在所述第一极片上的投影覆盖至少一个所述第一区域(30)，且满足：所述第四胶层(84)位于所第二凹槽(921)第四侧的部分在所述第一极片上的投影覆盖0～8个所述第一区域(30)；和/或，
    所述第四胶层(84)位于所述第二凹槽(921)第五侧的部分在所述第一极片上的投影覆盖0～8个所述第一区域(30)；和/或，
    所述第四胶层(84)位于所述第二凹槽(921)第六侧的部分在所述第一极片上的投影覆盖0～40个所述第一区域(30)。
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