WO2023240482A1 - 极片及制作方法、电极组件、二次电池和用电装置 - Google Patents

极片及制作方法、电极组件、二次电池和用电装置 Download PDF

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Publication number
WO2023240482A1
WO2023240482A1 PCT/CN2022/098870 CN2022098870W WO2023240482A1 WO 2023240482 A1 WO2023240482 A1 WO 2023240482A1 CN 2022098870 W CN2022098870 W CN 2022098870W WO 2023240482 A1 WO2023240482 A1 WO 2023240482A1
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WIPO (PCT)
Prior art keywords
lithium
distribution area
area
active material
replenishment
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PCT/CN2022/098870
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English (en)
French (fr)
Inventor
陈兴布
叶永煌
孙信
吴李力
刘润蝶
李璇
董苗苗
云亮
宋佩东
Original Assignee
宁德时代新能源科技股份有限公司
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Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to CN202280064544.7A priority Critical patent/CN117999670A/zh
Priority to EP22944048.2A priority patent/EP4336586A1/en
Priority to KR1020247002240A priority patent/KR20240024951A/ko
Priority to PCT/CN2022/098870 priority patent/WO2023240482A1/zh
Publication of WO2023240482A1 publication Critical patent/WO2023240482A1/zh
Priority to US18/409,803 priority patent/US20240145794A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4242—Regeneration of electrolyte or reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of battery technology, and in particular to a pole piece and a manufacturing method, an electrode assembly, a secondary battery and an electrical device.
  • lithium replenishment methods such as lithium strip rolling will cause too much lithium replenishment in the thinned area and cause lithium precipitation problems, or too little lithium replenishment in the large middle area will cause capacity loss or insufficient life improvement as expected. question.
  • the present application provides a pole piece, including: a current collecting structure; two active layers respectively provided on opposite sides of the current collecting structure along the thickness direction of the current collecting structure; the current collecting structure is provided with a There are several lithium replenishing spaces leading to one side of the active layer, and the lithium replenishing spaces contain lithium replenishing agents; in the distribution area on the active layer connected to the lithium replenishing spaces, the average weight of the active material per unit area of the active layer is recorded as M A , The sum of the internal volumes of the lithium supplement space covered by the projection of the distribution area along the thickness direction of the current collecting structure is recorded as V0.
  • the distribution area at least includes the first distribution area and the second distribution area; where M A in the first distribution area is less than MA in the second distribution area, and the corresponding V0 in the first distribution area is smaller than the corresponding V0 in the second distribution area.
  • a lithium replenishing space is set on the current collector structure so that the lithium replenishing space remains connected to the active layer on one side; the lithium replenishing agent in the lithium replenishing space is used to replenish lithium into the battery to offset the irreversible loss of lithium during the cycle. losses to increase the total capacity and energy density of the battery. Since the average weight MA of the active material corresponding to at least two distribution areas on the active layer is different, this application positively controls the lithium replenishment space corresponding to each distribution area according to the change in the average weight of the active material in the different distribution areas.
  • the sum of the volumes in the pores V0 that is, the sum of the volumes in the corresponding lithium replenishing spaces in the second distribution area is larger, and the sum of the volumes in the corresponding lithium replenishing spaces in the first distribution area is smaller.
  • different lithium supplements can be supplemented for different distribution areas to achieve quantitative and precise lithium supplementation, thus avoiding the problem of lithium deposition caused by too much lithium supplementation in the first distribution area, or excessive lithium supplementation in the second distribution area under the premise of the same lithium supplementation amount. If the battery is too small, the problem of capacity loss or insufficient life improvement will occur, which will help improve the battery energy density and life.
  • the depth of the lithium replenishment space is denoted as d
  • the thickness of the active layer corresponding to the location of the lithium replenishment space is denoted as h; wherein h in the first distribution area is smaller than h in the second distribution area, and h in the first distribution area is smaller than h in the second distribution area, and h is The corresponding d in one distribution area is smaller than the corresponding d in the second distribution area.
  • the depth d of the lithium replenishment space satisfies the following relationship:
  • C A is the first lithium insertion capacity of the negative active material in mAh/g (mAh/g)
  • C C is the first delithiation capacity of the positive active material in mAh/g
  • M C is the average weight of the active material per unit area of the positive electrode.
  • P is the proportion of the opening area of all lithium-supplementing spaces per unit area on the current collecting structure.
  • the proportion P of the opening area of all lithium replenishing spaces per unit area satisfies the following relationship: 10% ⁇ P ⁇ 50%. In this way, while ensuring that there is enough space to accommodate the lithium replenishing agent, the pore area ratio of the lithium replenishing space is reasonably controlled to ensure that the electron conduction function of the current collecting structure is stable.
  • the depth d of the lithium replenishment space satisfies the following relationship:
  • CE C is the first Coulombic efficiency of the positive active material
  • CE A is the first Coulombic efficiency of the negative active material
  • C A is the first lithium insertion capacity mAh/g of the negative active material.
  • the lithium supplementary spaces are arranged at intervals, and the distance between any two adjacent lithium supplementary spaces is equal. In this way, the lithium replenishment space is evenly arranged, which facilitates the uniform diffusion of lithium replenishment and makes the battery perform better.
  • the current collecting structure includes at least one current collector along the thickness direction of the current collecting structure, and in the current collector provided with the active layer, at least one lithium replenishing space is provided therethrough. In this way, it not only facilitates electron conduction, but also facilitates opening of holes in the current collecting structure, so that the lithium replenishing agent can be stably deposited in the lithium replenishing space.
  • the current collecting structure includes two current collectors, two active layers are respectively disposed on two sides of the two current collectors facing away from each other, and both current collectors are provided with lithium replenishing spaces. There are lithium replenishment spaces running through the two current collectors, so that the active layers on both sides can effectively replenish lithium, further improving the energy density and cycle life of the battery.
  • the current collector structure further includes at least one lithium supplement layer, and the lithium supplement layer is located between the two current collectors. Setting at least one lithium replenishing layer between two current collectors to increase the amount of lithium replenishing can effectively improve the cycle life of the battery.
  • the lithium replenishing space is a lithium replenishing hole, and the lithium replenishing hole extends into the active layer on either side along the thickness direction of the current collecting structure.
  • the lithium replenishment space is designed as a lithium replenishment hole, and one end of the lithium replenishment hole is extended into the active layer. This not only helps to simplify the production process of the electrode piece, but is also more conducive to controlling the corresponding lithium replenishment dosage in different distribution areas. , achieving more precise lithium supplementation.
  • the first distribution area extends around the periphery of the second distribution area. Therefore, the average weight MA of the active material near the edge of the pole piece is smaller than the average weight MA of the active material near the middle of the pole piece. This design is helpful to solve the problem of bulging at the edge of the pole piece due to excessive thickness.
  • the application provides a pole piece manufacturing method, which includes the following steps: Step S100, providing two single-sided pole pieces, wherein the single-sided pole piece includes a current collector and an active layer located on one side of the current collector; Step S200: On at least one single-sided pole piece, open lithium replenishment holes extending into the active layer on the current collector, and control the average weight M A of the active material per unit area in at least two distribution areas on the active layer and the corresponding lithium replenishment holes.
  • the sum of the pore volumes V0 satisfies: M A in the first distribution area is smaller than M A in the second distribution area, and the corresponding V0 in the first distribution area is smaller than the corresponding V0 in the second distribution area, where,
  • the distribution area includes a first distribution area and a second distribution area; step S300, deposit a lithium replenishing agent in the lithium replenishing hole; step S400, attach the sides of the two single-sided pole pieces facing away from the active layer to each other.
  • the above-mentioned pole piece production method uses unidirectional pole pieces to fit together to produce the required pole pieces, which greatly simplifies the production process; at the same time, it is also convenient to open holes in the pole pieces to ensure that the lithium replenishing agent is stably deposited in the lithium replenishing holes. To achieve quantitative and accurate lithium supplementation effect.
  • step S200 includes: step S210, obtaining the thickness h of the active layer in different distribution areas; step S220, evenly opening a number of lithium filling holes in the current collector; step S230, controlling the projection of each distribution area on the current collector.
  • the depth d of the lithium filling holes in the region is such that h in the first distribution region is smaller than h in the second distribution region, and the corresponding d in the first distribution region is smaller than the corresponding d in the second distribution region.
  • the control of the sum of the intrapore volume parameters of the lithium replenishment hole is transformed into the control of the depth of the lithium replenishment hole, which can not only achieve quantitative and precise lithium replenishment effects, but also simplify the lithium replenishment hole.
  • the processing technology improves the production efficiency of pole pieces.
  • the depth d of the lithium filling hole satisfies the following relationship:
  • C A is the first lithium insertion capacity mAh/g of the negative electrode active material
  • C C is the first lithium removal capacity mAh/g of the positive electrode active material
  • M C is the average weight of the positive electrode active material per unit area g/cm 2
  • P is The ratio of the area of all lithium replenishing holes per unit area on the current collecting structure.
  • the depth d of the lithium filling hole satisfies the following relationship:
  • CE C is the first Coulombic efficiency of the positive active material
  • CE A is the first Coulombic efficiency of the negative active material
  • C A is the first lithium insertion capacity mAh/g of the negative active material.
  • the present application provides an electrode assembly, including a positive electrode piece, a negative electrode piece, and a separator disposed between the positive electrode piece and the negative electrode piece; wherein the positive electrode piece and/or the negative electrode piece is any one of the above. .
  • the above-mentioned electrode assembly uses the above pole pieces to supplement different lithium according to different distribution areas, achieving quantitative and precise lithium supplementation, which is beneficial to improving the energy density and life of the battery.
  • the present application provides a secondary battery including the above electrode assembly.
  • the above-mentioned secondary batteries use the above pole pieces to supplement different lithium according to different distribution areas, achieving quantitative and precise lithium supplementation, which is beneficial to improving the energy density and life of the battery.
  • the present application provides an electrical device, including the above secondary battery.
  • Figure 1 is a schematic structural diagram of a vehicle described in some embodiments of the present application.
  • Figure 2 is an exploded view of a battery described in some embodiments of the present application.
  • Figure 3 is a partial structural schematic diagram of the pole piece described in some embodiments of the present application.
  • Figure 4 is a structural cross-sectional view of the pole piece described in some embodiments of the present application.
  • Figure 5 is a flow chart 1 of the pole piece manufacturing method described in some embodiments of the present application.
  • Figure 6 is a flow chart 2 of the pole piece manufacturing method described in some embodiments of the present application.
  • an embodiment means that a particular feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application.
  • the appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art understand, both explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.
  • multiple refers to more than two (including two).
  • multiple groups refers to two or more groups (including two groups), and “multiple pieces” refers to It is more than two pieces (including two pieces).
  • Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles and electric cars, as well as in many fields such as military equipment and aerospace. . As the application fields of power batteries continue to expand, their market demand is also constantly expanding.
  • the organic electrolyte will be reduced and decomposed on the surface of the negative electrode such as graphite to form a solid electrolyte phase interface film, permanently consuming a large amount of lithium from the positive electrode, resulting in a bias in the Coulombic efficiency of the first cycle. Low, reducing the capacity and energy density of lithium-ion batteries.
  • lithium replenishment methods such as lithium ribbon rolling can be used to add lithium to the interior of the battery to replenish lithium ions.
  • a current collector such as copper foil or aluminum foil
  • the slurry is transferred to a current collector, such as copper foil or aluminum foil, through a steel roller to form a coating area with a uniform thickness; it is then passed through a tunnel drying oven Bake.
  • the solid content at the edge of the coating area on the current collector rises faster than that in the middle area.
  • the surface tension of the slurry at the edge of the coating area is greater than the surface tension in the middle part, and the slurry flows to the edge area. This results in a "thick edge" phenomenon on the pole piece after drying.
  • the edge of the pole piece In order to avoid the thick edge of the pole piece, it is usually necessary to thin the edge of the pole piece, such as using a thinning device or a transfer coating machine to thin the edge.
  • the amount of active material in different distribution areas on the pole piece will be different. For example, the amount of active material in the large middle area of the pole piece and the thinned area on the edge will be different.
  • the same amount of lithium supplement is arranged on the pole piece, because the amount of lithium deintercalation of the active material in the edge thinning area and the amount of deintercalation in the middle large surface area are smaller, under the same lithium supplementation amount, thinning will occur. Too much lithium is replenished in the area, causing lithium precipitation problems, or too little lithium is replenished in the large area in the middle, causing capacity loss or insufficient lifespan improvement.
  • the inventor designed a pole piece after in-depth research.
  • the average weight of the active material per unit area of the active layer was recorded as M A
  • the sum of the pore volumes of the lithium replenishing space covered by the projection of the distribution area along the thickness direction of the current collecting structure is recorded as V0.
  • MA in the first distribution area is smaller than MA in the second distribution area
  • the corresponding V0 in the first distribution area is smaller than the corresponding V0 in the second distribution area.
  • the sum of the pore volumes V0 of the lithium replenishment space corresponding to each distribution area is controlled by positive correlation, that is, the corresponding volume in the second distribution area
  • the sum of the volumes in the lithium replenishment space is larger, and the sum of the volumes in the corresponding lithium replenishment space in the first distribution area is smaller.
  • the battery cells disclosed in the embodiments of the present application can be used in, but are not limited to, electrical devices such as vehicles, ships, or aircrafts.
  • the power supply system of the electrical device can be composed of the battery cells and batteries disclosed in this application. In this way, different lithium can be supplemented for different distribution areas to achieve quantitative and precise lithium supplementation, which is beneficial to improving the energy density and life of the battery.
  • Embodiments of the present application provide an electrical device that uses a battery as a power source.
  • the electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc.
  • electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, electric airplane toys, etc.
  • spacecraft can include airplanes, rockets, space shuttles, spaceships, etc.
  • an electric device 1000 according to an embodiment of the present application is used as an example.
  • FIG. 1 is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application.
  • the vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.
  • the battery 100 is disposed inside the vehicle 1000 , and the battery 100 may be disposed at the bottom, head, or tail of the vehicle 1000 .
  • the battery 100 may be used to power the vehicle 1000 , for example, the battery 100 may serve as an operating power source for the vehicle 1000 .
  • the vehicle 1000 may also include a controller 200 and a motor 300 .
  • the controller 200 is used to control the battery 100 to provide power to the motor 300 , for example, for starting, navigating and driving the vehicle 1000 .
  • the battery 100 can not only be used as an operating power source for the vehicle 1000 , but also can be used as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .
  • FIG. 2 is an exploded view of the battery 100 provided by some embodiments of the present application.
  • the battery 100 includes a case 110 and a battery cell 120.
  • the battery cell 120 is accommodated in the case 110.
  • the box 110 is used to provide a storage space for the battery cells 120, and the box 110 can adopt a variety of structures.
  • the box 110 may include a first part 111 and a second part 112 , the first part 111 and the second part 112 cover each other, and the first part 111 and the second part 112 jointly define a space for accommodating the battery cell 120 of accommodation space.
  • the second part 112 may be a hollow structure with one end open, and the first part 111 may be a plate-like structure.
  • the first part 111 covers the open side of the second part 112 so that the first part 111 and the second part 112 jointly define a receiving space.
  • the first part 111 and the second part 112 may also be hollow structures with one side open, and the open side of the first part 111 is covered with the open side of the second part 112.
  • the box 110 formed by the first part 111 and the second part 112 can be in various shapes, such as a cylinder, a cuboid, etc.
  • the battery 100 there may be a plurality of battery cells 120, and the plurality of battery cells 120 may be connected in series, in parallel, or in mixed connection.
  • Mixed connection means that the plurality of battery cells 120 are connected in series and in parallel.
  • the plurality of battery cells 120 can be directly connected in series or in parallel or mixed together, and then the whole composed of the plurality of battery cells 120 can be accommodated in the box 110 ; of course, the battery 100 can also be a plurality of battery cells 120
  • the battery 100 modules are first connected in series, parallel, or mixed, and then multiple battery 100 modules are connected in series, parallel, or mixed to form a whole, and are accommodated in the box 110 .
  • the battery 100 may also include other structures.
  • the battery 100 may further include a bus component for realizing electrical connections between multiple battery cells 120 .
  • Each battery cell 120 may be a secondary battery 100 or a primary battery 100; it may also be a lithium-sulfur battery 100, a sodium-ion battery 100 or a magnesium-ion battery 100, but is not limited thereto.
  • the battery cell 120 may be in the shape of a cylinder, a flat body, a rectangular parallelepiped, or other shapes.
  • the present application provides a pole piece 10 .
  • the pole piece 10 includes: a current collecting structure 11 and two active layers 12 .
  • the two active layers 12 are respectively provided on opposite two sides of the current collecting structure 11 along the thickness direction of the current collecting structure 11 .
  • the current collecting structure 11 is provided with a number of lithium replenishing spaces 13 leading to one side of the active layer 12 .
  • the lithium supplement space 13 contains a lithium supplement agent.
  • the average weight of the active material per unit area of the active layer 12 is recorded as MA .
  • the distribution area 14 at least includes a first distribution area 14a and a second distribution area 14b.
  • the MA in the first distribution area 14a is smaller than the MA in the second distribution area 14b, and the corresponding V0 in the first distribution area 14a is smaller than the corresponding V0 in the second distribution area 14b.
  • the current collecting structure 11 refers to a component or part that can not only carry active material, but also collect and output the current generated by the electrode active material. This component or part may have one or more layers of structure.
  • the material of the current collecting structure 11 can be selected from a variety of materials, such as but not limited to metal materials such as copper, aluminum, nickel, stainless steel, etc.; of course, it can also be semiconductor materials such as carbon, conductive resin, titanium-nickel shape memory alloy, coating, etc. Carbon aluminum foil and other composite materials.
  • the active layer 12 refers to the active material coated on the current collecting structure 11 , and its specific composition is different depending on the polarity of the pole piece 10 .
  • the active material on the positive electrode sheet can be, but is not limited to, lithium cobalt oxide, lithium manganate, lithium nickel oxide, lithium iron phosphate, ternary materials, etc.
  • the active material on the negative electrode sheet can be, but is not limited to, graphite, lithium titanate, silicon oxide, etc.
  • the lithium replenishing agent refers to a substance that can replenish lithium ions inside the battery 100.
  • the lithium replenishing agent can be but is not limited to lithium foil, lithium powder, lithium silicide powder, etc.
  • the lithium replenishing agent can be but is not limited to Li 2 NiO 2 , Li 5 FeO 4 , Li 2 O, etc.
  • the lithium replenishing agent can be formed in the lithium replenishing space 13 by rolling or deposition.
  • the deposition method can be but is not limited to magnetron sputtering deposition.
  • the lithium replenishment space 13 refers to a space on the current collection structure 11 that can accommodate the lithium replenishment agent, such as a hole-like or groove-like structure; or a concave structure, etc.
  • the lithium replenishing space 13 is a concave structure on the current collecting structure 11, the surface of the current collecting structure 11 may be wavy.
  • the active layer 12 has a plurality of distribution areas 14 on a side facing away from the current collecting structure 11, and the average weight of the active material per unit area in at least two distribution areas 14 is different. For example, after the edge of the pole piece 10 is thinned, the average weight of the active material per unit area in the edge is generally smaller than the average weight of the active material in the middle distribution area 14 of the pole piece 10.
  • the factors that affect the average weight of the active material per unit area may be but are not limited to the type of the active material, the thickness of the active material, the density of the active material, etc. Therefore, when setting up the lithium supplement space 13, using the average weight of the active material per unit area as a reference basis can more comprehensively consider the conditions that affect the lithium supplement effect, making the lithium supplement amount more accurate.
  • the thickness direction of the current collecting structure 11 is the direction pointed by any arrow S in FIG. 3 .
  • each distribution area 14 is projected in the thickness direction of the current collection structure 11 It can frame part of the lithium-supplementing space 13, and the sum of the pore volumes of this part of the lithium-supplementing space 13 is recorded as V0.
  • the size of the pore volume of the lithium replenishment space 13 can determine the total amount of lithium replenishment corresponding to the corresponding distribution area 14 .
  • the influencing factors of the sum of the pore volumes of the lithium replenishment space 13 corresponding to each distribution area 14 may be, but are not limited to, the depth of the lithium replenishment space 13, the opening area of the lithium replenishment space 13, the lithium replenishment space 13, and the lithium replenishment space 13. The distribution density of space 13, etc.
  • the fact that the lithium replenishing space 13 can lead to the active layer 12 means that one end of the lithium replenishing space 13 is connected to the active layer 12 and the lithium replenishing agent in the lithium replenishing space 13 can penetrate into the active layer 12 to achieve the lithium replenishing effect.
  • the lithium replenishment space 13 can be connected to the active layer 12 by opening a space on the side of the current collection structure 11 facing the active layer 12 , or by extending one end of the lithium replenishment space 13 to the inside of the active layer 12 .
  • the sum of the volumes in the lithium replenishment spaces 13 refers to the sum of the internal volumes of multiple lithium replenishment spaces 13 corresponding to one distribution area 14 .
  • the shape of the lithium replenishing space 13 can have a variety of designs, for example, it can be any one or more of a circle, a square, a rhombus, a triangle, etc.
  • the opening areas of all the lithium replenishing spaces 13 may be consistent or inconsistent.
  • the opening areas of all the lithium replenishing spaces 13 may be of different sizes.
  • the opening area of the lithium replenishment space 13 should be as small as possible.
  • the lithium replenishment space 13 is circular or square, its diameter or width can be 5 microns (um) to 1 mm. (mm).
  • the diameter or width of the lithium replenishment space 13 may be 30um to 200um.
  • the diameter or width of the lithium replenishment space 13 may be but not limited to 30um, 50um, 70um, 90um, 100um, 120um, 150um, 180um, 200um.
  • the lithium replenishing space 13 can be provided on one side of the current collecting structure 11 , or the lithium replenishing space 13 can be provided on both sides of the current collecting structure 11 . If the lithium replenishment space 13 is only provided on one side of the current collecting structure 11, the pole piece 10 will have a lithium replenishment effect on one side.
  • a lithium replenishing space 13 is provided on the current collection structure 11 so that the lithium replenishing space 13 is within the active layer 12 on one side; the lithium replenishing agent in the lithium replenishing space 13 is used to replenish lithium into the battery 100 to offset the irreversible loss of lithium during the cycle. losses to increase the total capacity and energy density of the battery 100. Since the average weight M A of the active material corresponding to at least two distribution areas 14 on the active layer 12 is different, the present application positively controls the weight of the active material corresponding to each distribution area 14 according to the changes in the average weight of the active material in the different distribution areas 14 .
  • the sum of the pore volumes V0 of the lithium replenishment spaces 13, that is, the sum of the volumes in the corresponding lithium replenishment spaces 13 in the second distribution area 14b is larger, and the sum of the volumes in the corresponding lithium replenishment spaces 13 in the first distribution area 14a is larger.
  • Small In this way, different lithium is supplemented for different distribution areas 14 to achieve quantitative and precise lithium supplementation, thereby avoiding the problem of lithium deposition caused by too much lithium supplementation in the first distribution area 14a or the second distribution area 14b supplementation under the premise of the same lithium supplementation amount. If the amount of lithium is too small, problems such as capacity loss or insufficient life improvement may occur, which is beneficial to improving the battery's 100 energy density and lifespan.
  • the depth of the lithium replenishing space 13 is marked as d.
  • the thickness of the active layer 12 corresponding to the location of the lithium replenishing space 13 is denoted as h.
  • h in the first distribution area 14a is smaller than h in the second distribution area 14b
  • the corresponding d in the first distribution area 14a is smaller than the corresponding d in the second distribution area 14b.
  • the thickness of the active layer 12 corresponding to the location of the lithium replenishment space 13 can be understood as: extending the location of the lithium replenishment space 13 along the thickness direction of the current collecting structure 11 to the surface of the active layer 12, the path length penetrating the active layer 12 is corresponding thickness of the active layer 12 .
  • the thickness of the active layer 12 As a reference for opening space, it should be ensured as much as possible that the active layers 12 on one side of the current collecting structure 11 are all of the same type of active material, and the density of the active layer 12 on the current collecting structure 11 is also the same. Guaranteed to be the same etc.
  • the control of the sum of the volume parameters in the lithium replenishment space 13 is transformed into the control of the depth of the lithium replenishment space 13 , which can not only achieve quantitative and precise lithium replenishment effects , and also simplifies the processing technology of the lithium replenishment space 13 and improves the production efficiency of the pole piece 10 .
  • the depth d of the lithium replenishment space 13 satisfies the following relationship: Among them, C A is the first lithium insertion capacity of the negative electrode active material, milliampere hours/gram (mAh/g), C C is the first lithium removal capacity of the positive electrode active material, mAh/g, and M C is the average active material per unit area of the positive electrode. Weight, grams per square centimeter (g/cm 2 ), P is the proportion of the area of all lithium supplementary spaces 13 in the unit area.
  • the proportion of the hole area of all lithium-supplementing spaces 13 in the unit area should be understood as: the ratio between the sum of the cross-sectional areas of all the lithium-supplementing spaces 13 in the unit area and "1".
  • the depth of the lithium replenishment space 13 satisfies this inequality relationship.
  • the proportion P of the opening area of all lithium replenishing spaces 13 per unit area satisfies the following relationship: 10% ⁇ P ⁇ 50%.
  • the proportion of the opening area of the lithium filling space 13 should not be too large. If the proportion of the area of the lithium filling space 13 is too large, it will result in more hollow parts on the current collecting structure 11, seriously affecting its own electronic conduction. Function.
  • the proportion P of the opening area of all lithium replenishing spaces 13 per unit area may be, but is not limited to, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50 %wait.
  • the depth d of the lithium replenishment space 13 satisfies the following relationship:
  • CE C is the first Coulombic efficiency of the positive active material
  • CE A is the first Coulombic efficiency of the negative active material
  • C A is the first lithium insertion capacity mAh/g of the negative active material.
  • the first Coulombic efficiency of the positive active material is the ratio of the first lithium insertion capacity mAh/g of the positive active material to the first lithium removal capacity mAh/g of the positive active material.
  • the first Coulombic efficiency of the negative active material is the ratio of the first lithium removal capacity mAh/g of the negative active material to the first lithium insertion capacity mAh/g of the negative active material.
  • the capacity of deintercalating lithium for the first time can be tested by preparing a button battery.
  • the positive and negative electrodes are configured with slurry according to the conventional formula, and the pole piece 10 is coated on one side, cut into small buckle discs, and composed of buckle batteries with lithium metal sheets. Half cell. The positive electrode piece is tested at a charge and discharge rate of 0.1C/0.1C.
  • the positive electrode material is charged first and then discharged.
  • the first charge capacity is the first lithium removal capacity of the positive active material, and the first discharge capacity is the first lithium insertion capacity of the positive active material.
  • the negative electrode piece is tested at a charge and discharge rate of 0.1C/0.05C.
  • the negative electrode material is first discharged and then charged.
  • the first discharge capacity is the first lithium insertion capacity of the negative active material, and the first charging capacity is the first delithiation of the negative active material. capacity.
  • the depth d of the lithium supplement space 13 When the depth d of the lithium supplement space 13 is greater than or equal to time, it can ensure that the capacity of the positive active material is fully exerted, effectively improving the battery's 100 capacity and energy density. At the same time, as the depth d further increases, the amount of lithium supplement also increases. Although the capacity of the positive active material has reached its limit at this time and will not increase further, it can effectively increase the cycle life.
  • the depth d of lithium replenishment space 13 is greater than or equal to and less than or equal to When , the lithium replenishment effect of battery 100 is better. If the depth d of the lithium supplement space 13 cannot simultaneously satisfy the requirements of greater than or equal to and less than or equal to When , priority should be given to controlling the depth d of the lithium replenishment space 13 to be less than or equal to Of course, in this case, the depth d of the lithium replenishment space 13 can be controlled to satisfy the above two inequalities at the same time by increasing the average weight of the active material per unit area of the negative electrode.
  • the lithium replenishment space 13 can be filled with a lithium replenishing agent (such as metallic lithium, etc.), which can fully utilize the capacity of the positive electrode active material and effectively increase the energy density.
  • a lithium replenishing agent such as metallic lithium, etc.
  • the lithium replenishment spaces 13 are arranged at intervals, and the spacing between any two adjacent lithium replenishment spaces 13 is equal.
  • the equal spacing between any two adjacent lithium replenishment spaces 13 can be understood as: the lithium replenishment spaces 13 on one side of the current collecting structure 11 are evenly spaced, that is, the distribution density of the lithium replenishment spaces 13 is constant. At this time, the sum of the volumes in the corresponding lithium replenishment spaces 13 in each distribution area 14 mainly depends on the depth of the lithium replenishment spaces 13. In this way, when controlling the changing relationship between V0 and M A , it can be effectively converted into d and The changing relationship between h.
  • the active layer 12 In at least one side of the active layer 12 , it means that in the pole piece 10 of the present application, only one side of the active layer 12 can have a number of lithium supplementary spaces 13 ; of course, it can also be provided correspondingly on both sides of the active layer 12 Some lithium supplementation spaces13.
  • the lithium replenishment spaces 13 are evenly distributed, so that quantitative and precise lithium replenishment effects can be achieved simply by controlling the depth of the lithium replenishment spaces 13; at the same time, the lithium replenishment spaces 13 are evenly arranged to facilitate replenishment.
  • the lithium diffuses evenly, allowing the battery 100 to perform better.
  • the current collecting structure 11 includes at least one current collecting structure 11 a along the thickness direction of the current collecting structure 11 .
  • the current collector 11a provided with the active layer 12 at least one lithium replenishing space 13 is provided therethrough.
  • the current collector 11a refers to a component or part that can not only carry the active material, but also collect and output the current generated by the electrode active material. It is the core structure that constitutes the current collector structure 11.
  • the number of current collectors 11a may be one or multiple. When there is one current collector 11a, the two active layers 12 are disposed on opposite sides of the same current collector 11a; when there are multiple current collectors 11a, the two active layers 12 are respectively disposed on the current collector structure 11. On the current collectors 11a at the outermost ends in the thickness direction. In addition, when there are multiple current collectors 11 a , the plurality of current collectors 11 a are stacked along the thickness direction of the current collecting structure 11 .
  • the lithium replenishment space 13 on the current collector 11a there are many design states of the lithium replenishment space 13 on the current collector 11a.
  • the lithium replenishment space 13 provided on the current collector can be extended to one side; or, a part of the lithium replenishment space 13 can be It extends toward the active layer 12 on one side, and the other part of the lithium replenishing space 13 extends toward the active layer 12 on the other side.
  • the lithium replenishing space 13 extends toward the corresponding active layer 12; or, the two current collectors 11a located at the outermost ends are both provided. There are 13 lithium supplement spaces throughout.
  • Designing the current collecting structure 11 as at least one current collector 11a not only facilitates electron conduction, but also facilitates opening holes in the current collecting structure 11 so that the lithium replenishing agent can be stably deposited in the lithium replenishing space 13 .
  • the current collector 11a includes two.
  • the two active layers 12 are respectively provided on the side surfaces of the two current collectors 11a facing away from each other.
  • the two current collectors 11a are both provided with lithium replenishing spaces 13 .
  • the lithium replenishment space 13 can be distributed in various ways on the current collector 11a.
  • the lithium replenishment space 13 can be evenly distributed on the current collector 11a; or the distribution density of the lithium replenishment space 13 can be distributed according to the thickness of the active layer 12.
  • a thick active layer 12 corresponds to a distribution of more lithium-replenishing spaces 13
  • a thin active layer 12 corresponds to a distribution of fewer lithium-replenishing spaces 13 .
  • the distribution of the lithium replenishment spaces 13 on one current collector 11a is completely staggered with the distribution of the lithium replenishment spaces 13 on the other current collector 11a, that is, The lithium replenishment space 13 on one side is not connected with the lithium replenishment space 13 on the other side; or, the distribution of the lithium replenishment space 13 on one current collector 11a is completely aligned with the distribution of the lithium replenishment space 13 on the other current collector 11a, that is, a The lithium replenishment space 13 on one side is connected to the lithium replenishment space 13 on the other side, etc.
  • the lithium replenishing agent in the lithium replenishing spaces 13 on the two current collectors 11a can be shared with each other, that is, the lithium replenishing agent in the lithium replenishing space 13 on one side can be used. Replenish lithium in the active layer 12 on the other side.
  • connection method between the two current collectors 11a may be, but is not limited to, welding, bonding, etc.
  • two current collectors 11a coated with the active layer 12 are bonded to each other on the side with the lithium supplementary space 13; after being bonded, the two current collectors 11a are welded or bonded. circumferential edge connections, etc.
  • Lithium replenishment spaces 13 are respectively provided on the two current collectors 11a, so that the active layers 12 on both sides can effectively replenish lithium, further improving the energy density and cycle life of the battery 100.
  • the current collection structure 11 further includes at least one lithium supplement layer 15 .
  • the lithium supplement layer 15 is located between the two current collectors 11a.
  • the lithium replenishing layer 15 refers to a substance that can replenish lithium ions inside the battery 100.
  • the lithium replenishing layer 15 can be but is not limited to a metal lithium layer.
  • the lithium supplement layer 15 can be but is not limited to Li 2 NiO 2 , Li 5 FeO 4 , Li 2 O, etc.
  • lithium replenishing layer 15 There may be one lithium replenishing layer 15 between the two current collectors 11a, or there may be multiple lithium replenishing layers 15.
  • one lithium replenishing layer 15 is attached to the side of one current collector 11 a facing away from the active layer 12 ; the other lithium replenishing layer 15 is attached to the other side of the current collector 11 a facing away from the active layer 12 on one side.
  • At least one lithium replenishing layer 15 is provided between the two current collectors 11a to increase the lithium replenishing amount, which can effectively improve the cycle life of the battery 100.
  • the lithium replenishment space 13 is a lithium replenishment hole 13a.
  • the lithium filling hole 13 a extends along the thickness direction of the current collecting structure 11 into the active layer 12 on either side.
  • the lithium replenishment hole 13a extends into the active layer 12 along the thickness direction of the current collection structure 11. It should be understood that one end of the lithium replenishment hole 13a is located inside the active layer 12 and does not penetrate the active layer 12, that is, it is similar to a blind hole structure.
  • the lithium replenishment space 13 is designed as a lithium replenishment hole 13a, and one end of the lithium replenishment hole 13a is extended to the inside of the active layer 12. This is not only conducive to simplifying the manufacturing process of the pole piece 10, but is also more conducive to controlling the corresponding distribution in different distribution areas 14.
  • the dosage of lithium supplementation enables more precise lithium supplementation.
  • the first distribution area 14a extends around the periphery of the second distribution area 14b.
  • the first distribution area 14a is relatively close to the edge of the pole piece 10, and the second distribution area 14b is relatively close to the middle of the pole piece 10; at the same time, the first distribution area 14a has a linear ring structure.
  • the average weight MA of the active material near the edge of the pole piece 10 is smaller than the average weight MA of the active material near the middle of the pole piece 10. This design is helpful to solve the problem of bulging at the edge of the pole piece 10 due to excessive thickness.
  • a method for manufacturing the pole piece 10 includes the following steps:
  • S100 Provide two single-sided pole pieces 1610, wherein the single-sided pole piece 1610 includes a current collector 11a and an active layer 12 located on one side of the current collector 11a;
  • the single-sided pole piece 1610 can be roughly understood as half of the structure of the pole piece 10, that is, it includes a current collector 11a and an active layer 12 coated on one side of the current collector 11a. At this time, the other side of the current collector 11a The active layer 12 is not applied.
  • the manufacturing process of the single-sided pole piece 1610 may not be included in the manufacturing method of the pole piece 10 of the present application, and may be completed directly by the supplier or in other processes; of course, the manufacturing process of the single-sided pole piece 1610 may also be included in the pole piece 10 manufacturing method of the present application.
  • active material is coated on one side of the current collector 11a; after coating, the current collector 11a is rolled (cold pressed) to rearrange and densify the powder.
  • the edges of the single-sided pole piece 1610 are thinned. At this time, the average weights of the active materials in different distribution areas 14 on the active layer 12 are different.
  • step S200 there are many methods of drilling holes on the current collector 11a, such as laser drilling, roller pinning, etc.
  • step S300 when the lithium replenishing agent is deposited in the lithium replenishing hole 13a, the lithium replenishing agent should be fully deposited in the lithium replenishing hole 13a, that is, the lithium replenishing agent in the hole can be with one end of the lithium replenishing hole 13a on the current collector 11a Flush.
  • the deposition method of the lithium replenishing agent can be, but is not limited to, lithium strip rolling, magnetron sputtering deposition, etc.
  • step S400 one side of the two single-sided pole pieces 1610 facing away from the active layer 12 is attached to each other, which can be understood as one side of the perforated single-sided pole piece 1610 being attached to each other and assembled.
  • the active layer 12 on the single-sided pole piece 1610 faces the isolation member (such as a separator) respectively.
  • the required pole pieces 10 are made by attaching the unidirectional pole pieces 10 to each other, which greatly simplifies the manufacturing process; at the same time, it is also convenient to open holes in the pole pieces 10 to ensure that the lithium replenishing agent is stably deposited in the lithium replenishing holes 13a to achieve quantitative , precise lithium supplementation effect.
  • this application controls the lithium replenishment holes corresponding to each distribution area 14 in a positive correlation according to the changes in the average weight of the active material in the different distribution areas 14
  • the sum of the pore volumes V0 of 13a that is, the sum of the pore volumes of the corresponding lithium replenishment holes 13a in the second distribution area 14b is relatively large, and the sum of the pore volumes of the corresponding lithium replenishment holes 13a in the first distribution area 14a is relatively large. smaller.
  • opening a number of lithium replenishment holes 13a evenly should be understood as: the distance between any two adjacent lithium replenishment holes 13a is equal. Due to the size of the sum of the pore volumes of the lithium replenishment holes 13a corresponding to each distribution area 14, the influencing factors may be but are not limited to the hole depth of the lithium replenishment holes 13a, the distribution density of the lithium replenishment holes 13a, etc., therefore, controlling the replenishment The distribution density of lithium holes 13a is constant. At this time, the sum of the pore volumes of the corresponding lithium replenishment holes 13a in each distribution area 14 mainly depends on the hole depth of the lithium replenishment holes 13a. In this way, when controlling V0 and M A When the relationship between d and h changes, it can be effectively transformed into the changing relationship between d and h.
  • the control of the sum of the intrapore volume parameters of the lithium replenishment hole 13a is transformed into the control of the hole depth of the lithium replenishment hole 13a, which not only achieves quantitative and precise lithium replenishment effects, but also simplifies the replenishment process.
  • the processing technology of the lithium hole 13a improves the production efficiency of the pole piece 10.
  • the depth d of the lithium replenishing hole 13a satisfies the following relationship:
  • C A is the first lithium insertion capacity mAh/g of the negative electrode active material
  • C C is the first lithium removal capacity mAh/g of the positive electrode active material
  • M C is the average weight of the positive electrode active material per unit area g/cm 2
  • P is The proportion of the hole area of all lithium refill holes 13a per unit area on the current collecting structure 11.
  • the hole depth of the lithium replenishment hole 13a when designing the hole depth of the lithium replenishment hole 13a, an upper limit of the hole depth needs to be set.
  • the average weight of the active material per unit area of the negative electrode can be increased, for example, by coating the active material on the corresponding distribution area 14, etc., so that the The hole depth of the lithium filling hole 13a satisfies this inequality relationship.
  • the depth d of the lithium replenishing hole 13a satisfies the following relationship:
  • CE C is the first Coulombic efficiency of the positive active material
  • CE A is the first Coulombic efficiency of the negative active material
  • C A is the first lithium insertion capacity mAh/g of the negative active material.
  • the depth d of the lithium filling hole 13a When the depth d of the lithium filling hole 13a is greater than or equal to time, it can ensure that the capacity of the positive active material is fully exerted, effectively improving the battery's 100 capacity and energy density. At the same time, as the depth d further increases, the amount of lithium supplement also increases. Although the capacity of the positive active material has reached its limit at this time and will not increase further, it can effectively increase the cycle life.
  • the depth d of the lithium replenishing hole 13a is greater than or equal to and less than or equal to When , the lithium replenishment effect of battery 100 is better. If the depth d of the lithium filling hole 13a cannot simultaneously satisfy the requirements of greater than or equal to and less than or equal to When , priority should be given to controlling the depth d of the lithium replenishing hole 13a to be less than or equal to Of course, in this case, the depth d of the lithium replenishing hole 13a can be controlled to satisfy the above two inequalities at the same time by increasing the average weight of the active material per unit area of the negative electrode.
  • the lithium replenishing hole 13a can be filled with a lithium replenishing agent (such as metallic lithium, etc.), which can fully utilize the capacity of the positive electrode active material and effectively increase the energy density.
  • a lithium replenishing agent such as metallic lithium, etc.
  • the average weight of the active material per unit area M A in the first distribution area 14a at the edge of the negative electrode is 0.0075g/cm 2
  • the average weight of the active material per unit area in the second distribution area 14b at the edge of the negative electrode M A is 0.0100g/cm 2
  • the first lithium insertion capacity (charging capacity in grams) C A of the active material is 800mAh/g
  • the first efficiency of the negative electrode (first discharge capacity/first charging capacity) is 80%.
  • the hole depth corresponding to the second distribution area 14b is designed to be 0um (that is, no holes are punched), and the hole depth corresponding to the first distribution area 14a is designed to be 0um (that is, no holes are punched).
  • the comparative example The hole area ratio P of the lithium filling hole 13a in 1 is still recorded as 50%.
  • the average weight MC per unit area of the active material in the first distribution area 14a at the edge of the positive electrode is 0.0240g/cm 2 .
  • the average weight MC of the active material per unit area in the second distribution area 14b is 0.0300g/cm 2
  • the first lithium insertion capacity (charge capacity in grams) CC of the active material is 220 mAh/g
  • the first effect of the positive electrode is 90%.
  • the case depth d of the lithium replenishment holes 13a corresponding to the second distribution area 14b is designed to be 10um
  • the case depth d of the lithium replenishment holes 13a corresponding to the first distribution area 14a is designed d is designed to be 10um.
  • the depth d of the lithium replenishment holes 13a corresponding to the second distribution area 14b is designed to be 6.5um
  • the case depth d of the lithium replenishment holes 13a corresponding to the first distribution area 14a is designed
  • the depth d is designed to be 6.5um.
  • the case depth d of the lithium replenishment holes 13a corresponding to the second distribution area 14b is designed to be 10um
  • the case depth d of the lithium replenishment holes 13a corresponding to the first distribution area 14a is designed d is designed to be 6.5um.
  • the batteries 100 prepared in the above comparative examples and examples were subjected to a normal temperature cycle performance test, and the results are shown in Table 1-2.
  • the specific test steps are as follows:
  • the battery 100 with the lithium replenishing hole 13a on the pole piece 10 effectively improves the positive electrode capacity per gram compared to the battery 100 without holes in Comparative Example 1.
  • the number of cycles of the 80% capacity retention rate in Examples 2 and 3 was improved.
  • the number of cycles in Example 1 has been reduced, which shows that the hole depth of the lithium replenishing hole 13a is not larger and higher. It needs to be ensured to be less than or equal to the maximum hole depth of the different distribution areas 14. If it is too deep, it will be easy to Produces lithium precipitation.
  • the depth d of the lithium replenishing hole 13a changes in a positive correlation with the different distribution areas 14, for example: the depth d in the second distribution area 14b is designed to be larger, the depth d in the first distribution area 14a is designed to be smaller, etc., the positive electrode of the battery 100 The data of gram capacity and number of cycles are the best.
  • the influence of the depth d of the lithium replenishing hole 13a on the number of cycles of the battery 100 Under different chemical systems (that is, the current collectors 11a of the positive electrode sheet and the negative electrode sheet are of the same type), the influence of the depth d of the lithium replenishing hole 13a on the number of cycles of the battery 100.
  • the difference is at least that: in the negative electrode sheet, the hole area ratio P of the lithium supplement hole 13a per unit area is recorded as 50%; the case depth d design of the lithium supplement hole 13a corresponding to the second distribution area 14b is 5um, and the case depth d of the lithium filling hole 13a corresponding to the first distribution area 14a is designed to be 4um.
  • the difference is at least that: the case depth d of the lithium replenishment hole 13a corresponding to the second distribution area 14b is designed to be 20um, and the case depth d of the lithium replenishment hole 13a corresponding to the first distribution area 14a is designed to be 10um. .
  • the difference is at least that: in the negative electrode sheet, the negative electrode current collector 11a is low silicon.
  • the difference is at least that: in the positive electrode sheet, the positive electrode current collector 11a is LFP (LiFePO4 lithium iron phosphate).
  • the hole area ratio P of the lithium supplement hole 13a per unit area is recorded as 30%; the case depth d of the lithium supplement hole 13a corresponding to the second distribution area 14b It is designed to be 15um, and the case depth d of the lithium filling hole 13a corresponding to the first distribution area 14a is designed to be 10.5um.
  • the hole area ratio P of the lithium supplement hole 13a per unit area is recorded as 10%;
  • the case depth d of the lithium supplement hole 13a corresponding to the second distribution area 14b It is designed to be 40um, and the case depth d of the lithium refill hole 13a corresponding to the first distribution area 14a is designed to be 31um.
  • the difference is at least that: in the negative electrode sheet, the hole area ratio P of the lithium supplement hole 13a per unit area is recorded as 70%; the case depth d of the lithium supplement hole 13a corresponding to the second distribution area 14b It is designed to be 7um, and the case depth d of the lithium filling hole 13a corresponding to the first distribution area 14a is designed to be 4.5um.
  • the average weight MA per unit area of the active material in the first distribution area 14a at the edge of the negative electrode is 0.0068g/cm 2
  • the average weight M A per unit area in the second distribution area 14b at the edge of the negative electrode is The average weight of the substance M A is 0.0090g/cm 2 .
  • the case depth d of the lithium replenishment hole 13a corresponding to the second distribution area 14b is designed to be 5um.
  • the case depth d of the lithium replenishment hole 13a corresponding to the first distribution area 14a is designed to be 1.0um.
  • the average weight M A of the active material per unit area in the first distribution area 14a at the edge of the negative electrode is 0.0120g/cm 2
  • the average weight M A per unit area in the second distribution area 14b at the edge of the negative electrode is The average weight of the substance M A is 0.0150g/cm 2 .
  • the case depth d of the lithium replenishment hole 13a corresponding to the second distribution area 14b is designed to be 25um.
  • the case depth d of the lithium replenishment hole 13a corresponding to the first distribution area 14a is designed to be 20.0um.
  • the difference is at least that: in the negative electrode sheet, the hole area ratio P of the lithium supplement hole 13a per unit area is recorded as 50%, and the depth d of the lithium supplement hole 13a corresponding to the second distribution area 14b is designed. is 8um, and the case depth d of the lithium refill hole 13a corresponding to the first distribution area 14a is designed to be 5.0um.
  • the difference is at least that: in the negative electrode sheet, the hole area ratio P of the lithium supplement hole 13a per unit area is recorded as 50%, and the depth d of the lithium supplement hole 13a corresponding to the second distribution area 14b is designed. is 7um, and the case depth d of the lithium filling hole 13a corresponding to the first distribution area 14a is designed to be 4.0um.
  • the difference is at least that: in the negative electrode sheet, the hole area ratio P of the lithium supplement hole 13a per unit area is recorded as 50%, and the depth d of the lithium supplement hole 13a corresponding to the second distribution area 14b is designed. is 4.0um, and the case depth d of the lithium filling hole 13a corresponding to the first distribution area 14a is designed to be 3.0um.
  • the batteries 100 prepared in the above comparative examples and examples were subjected to a normal temperature cycle performance test, and the results are shown in Table 2-2.
  • Comparing Examples 7 to 8 with Comparative Example 3 it can be seen that when the hole depth of the lithium filling hole 13a cannot satisfy the above two inequalities at the same time, it is necessary to prioritize the depth d of the lithium filling hole 13a to satisfy less than or equal to At the same time, by increasing the average weight M A of the active material per unit area of the negative electrode, the hole depth d can be adjusted to satisfy the above two inequalities at the same time, and the positive electrode gram capacity and the number of cycles will be significantly improved.
  • Example 9 and Comparative Example 4 Example 10 and Comparative Example 5, and Example 11 and Comparative Example 6 that no matter what chemical system is used, the depth d of the lithium replenishing hole 13a satisfies the above two inequalities at the same time. , and the depth d changes in a positive correlation with the thickness of the negative active layer 12 in the different distribution areas 14 , the number of cycles of the battery 100 will be significantly improved, that is, the cycle life of the battery 100 can be effectively improved.
  • the present application provides an electrode assembly.
  • the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive electrode sheet and the negative electrode sheet.
  • the positive electrode piece and/or the negative electrode piece is the electrode piece 10 in any of the above solutions.
  • the present application provides a secondary battery 100.
  • the battery 100 includes the electrode assembly in the above solution.
  • the present application provides an electrical device, including the secondary battery 100 in the above solution.
  • this application also provides a long-life negative electrode and battery 100 to achieve quantitative and accurate lithium replenishment, and effectively control the amount of lithium replenishment to prevent fooling around.
  • the specific implementation is as follows:
  • the single-sided negative electrode sheet is drilled in different areas and depths through laser drilling, roller pinning, etc.;
  • the design of the hole depth d in different areas of the negative electrode sheet needs to satisfy the following relationship:
  • the design of the hole depth d in different areas of the negative electrode sheet needs to satisfy the following relationship:
  • the hole depth d needs to satisfy both Equation 1-1 and Equation 1-2.
  • the hole depth d needs to satisfy Equation 1-2 first to avoid safety risks caused by lithium precipitation.
  • the hole depth d can be adjusted to satisfy both equations 1-1 and 1-2.

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Abstract

一种极片（10）及其制作方法、电极组件、电池（100）和用电装置，在集流结构（11）上设置补锂空间（13），使得补锂空间（13）与一侧的活性层（12）相通；利用补锂空间（13）中的补锂剂向电池（100）内补充锂，抵消循环过程中不可逆锂的损耗，以提高电池（100）的总容量和能量密度。由于活性层（12）上不同分布区域（14）中所对应的单位面积活性物质平均重量Ma不同，因此，根据不同分布区域（14）中的单位面积活性物质平均重量的变化，正相关控制各个分布区域（14）所对应的补锂空间（13）的体积之和V0的大小，即当第一分布区域（14a）中的Ma小于第二分布区域（14b）中的Ma时，第一分布区域（14a）中所对应的V0小于所述第二分布区域（14b）中所对应的V0。这样针对不同分布区域（14）补充不同量的锂，实现定量、精准补锂，有利于提升电池（100）的能量密度和寿命。

Description

极片及制作方法、电极组件、二次电池和用电装置 技术领域
本申请涉及电池技术领域，特别是涉及一种极片及制作方法、电极组件、二次电池和用电装置。
背景技术
随着日益增长的能源需求，对锂离子电池的续航能力和使用寿命提出了越来越高的要求。通常硅负极的首次库伦效率较低，为将其应用于电池产品中，就必须对其进行补锂，以此来提升能量密度和寿命。
由于涂布工艺为了避免边缘厚边的问题，会对极片边缘进行削薄处理。而在一些情形下，锂带压延等补锂方式，会使得削薄区域补锂量太多而出现析锂问题，或者中间大面区域补锂量过少而出现容量损失或者寿命改善不足预期的问题。
发明内容
基于此，有必要提供一种极片及制作方法、电极组件、二次电池和用电装置，实现定量、精准补锂，提升电池能量密度和寿命。
第一方面，本申请提供了一种极片，包括：集流结构；两个活性层，分别设于集流结构沿集流结构的厚度方向的相对两侧面上，集流结构上设有用于通向一侧活性层的若干补锂空间，补锂空间内容纳有补锂剂；在与补锂空间相通的活性层上分布区域中，活性层的单位面积活性物质平均重量记为M A，分布区域沿集流结构的厚度方向投影所涵盖的补锂空间的内体积之和记为V0，分布区域至少包括第一分布区域与第二分布区域；其中，第一分布区域中的M A小于第二分布区域中的M A，且第一分布区域中所对应的V0小于第二分布区域中所对应的V0。
上述的极片，在集流结构上设置补锂空间，使得补锂空间与一侧的活性层保持相通；利用补锂空间中的补锂剂向电池内补充锂，抵消循环过程中不可逆锂的损耗，以提高电池的总容量和能量密度。由于活性层上至少两个分布区域中所对应的活性物质平均重量M A不同，因此，本申请根据不同分布区域中的活性物质平均重量变化，正相关控制各个分布区域所对应的补锂空间的孔内体积之和V0，即第二分布区域中对应的补锂空间内的体积之和较大，第一分布区域中对应补锂空间内的体积之和较小。这样针对不同分布区域补充不同锂， 实现定量、精准补锂，避免相同补锂量的前提下，导致第一分布区域补锂量太多而出现析锂问题，或者第二分布区域补锂量过少而出现容量损失或者寿命改善不足预期的问题，有利于提升电池能量密度和寿命。
在一些实施例中，补锂空间的深度记为d，补锂空间所在位置对应的活性层的厚度记为h；其中，第一分布区域中的h小于第二分布区域中的h，且第一分布区域中所对应的d小于第二分布区域中所对应的d。如此，不仅能实现定量、精准补锂效果，而且还简化补锂空间的加工工艺，提升极片制作效率。
在一些实施例中，补锂空间的深度d满足如下关系：
Figure PCTCN2022098870-appb-000001
其中，C A为负极活性物质的首次嵌锂容量毫安时/克(mAh/g)，C C为正极活性物质的首次脱锂容量mAh/g，M C为正极单位面积活性物质的平均重量克/平方厘米(g/cm 2)，P为集流结构上单位面积中所有补锂空间的开口面积的占比。如此，通过设置补锂空间的深度上限值，避免补充过量锂而导致负极侧循环过程产生析锂，有利于提升电池的安全性能。
在一些实施例中，单位面积中所有补锂空间的开口面积的占比P满足如下关系：10％≤P≤50％。如此，在保证满足具有足够容纳补锂剂的空间下，合理控制补锂空间的孔面积占比，确保集流结构的电子传导功能稳定。
在一些实施例中，补锂空间的深度d满足如下关系：
Figure PCTCN2022098870-appb-000002
其中，C.E. C为正极活性物质的首次库伦效率，C.E. A为负极活性物质的首次库伦效率，C A为负极活性物质的首次嵌锂容量mAh/g。如此，通过设置补锂空间的深度下限值，便于补锂空间中能填满补锂剂，可实现正极活性物质容量的充分发挥，有效提升能量密度。
在一些实施例中，在至少一侧的活性层中，补锂空间间隔排布，且任意相邻两个补锂空间之间的间距均相等。如此，均匀排布补锂空间，便于补锂扩散均匀，使得电池的性能更佳。
在一些实施例中，集流结构沿集流结构的厚度方向包括至少一个集流体，在设有活性层的集流体中，至少一个贯穿设有补锂空间。如此，不仅便于电子传导，而且方便在集流结构上开孔，使得补锂剂能稳定沉积在补锂空间中。
在一些实施例中，集流结构包括两个集流体，两个活性层分别对应设于两个集流体上相互背向的两个侧面上，两个集流体上均贯穿设有补锂空间。在两个集流体上分别贯穿设有补锂空间，使得两侧的活性层均能实现有效补锂，进一步提升电池的能量密度和循环寿 命。
在一些实施例中，集流结构还包括至少一个补锂层，补锂层位于两个集流体之间。在两个集流体之间设置至少一个补锂层，增加补锂量，能有效地提升电池的循环寿命。
在一些实施例中，补锂空间为补锂孔，补锂孔沿集流结构的厚度方向延伸至任一侧的活性层内。如此，将补锂空间设计成补锂孔，并将补锂孔一端延伸至活性层内部，这样不仅有利于简化极片的制作工序，而且还更有利于控制不同分布区域下对应的补锂剂量，实现更为精准的补锂。
在一些实施例中，第一分布区域环绕第二分布区域的外围延伸设置。由此，极片上靠边缘处的活性物质平均重量M A小于极片上靠近中部处的活性物质平均重量M A，如此设计，有利于解决极片边缘因过厚而出现鼓边的问题。
第二方面，本申请提供了一种极片制作方法，包括如下步骤：步骤S100、提供两个单面极片，其中，单面极片包括集流体及设于集流体一侧的活性层；步骤S200、在至少一个单面极片上，对集流体开设延伸至活性层内的补锂孔，并控制活性层上至少两个分布区域中单位面积活性物质平均重量M A与对应的补锂孔的孔内体积之和V0满足：第一分布区域中的M A小于第二分布区域中的M A，且第一分布区域中所对应的V0小于第二分布区域中所对应的V0，其中，分布区域包括第一分布区域和第二分布区域；步骤S300、在补锂孔中沉积补锂剂；步骤S400、将两个单面极片上背向活性层的一侧面相互贴合。
上述的极片制作方法，以单向极片相互贴合方式制作所需极片，大大简化制作工艺；同时，也便于在极片内开孔，保证补锂剂稳定沉积在补锂孔中，以实现定量、精准的补锂效果。
在一些实施例中，步骤S200中包括：步骤S210、获取不同分布区域中活性层的厚度h；步骤S220、在集流体均匀开设若干补锂孔；步骤S230、控制各个分布区域在集流体上投影区域中的补锂孔的深度d，以使第一分布区域中的h小于第二分布区域中的h，且第一分布区域中所对应的d小于第二分布区域中所对应的d。如此，以活性层的厚度作为参考，将补锂孔的孔内体积之和参数的控制转化为对补锂孔的深度的控制，不仅能实现定量、精准补锂效果，而且还简化补锂孔的加工工艺，提升极片制作效率。
在一些实施例中，补锂孔的深度d满足如下关系：
Figure PCTCN2022098870-appb-000003
其中，C A为负极活性物质的首次嵌锂容量mAh/g，C C为正极活性物质的首次脱锂容量mAh/g，M C为正极单位面积活性物质的平均重量g/cm 2，P为集流结构上单位面积中所有补锂孔孔面积的占比。如此设计，通过设置补锂孔的深度上限值，避免补充过量锂而导致 负极侧循环过程产生析锂，有利于提升电池的安全性能。
在一些实施例中，补锂孔的深度d满足如下关系：
Figure PCTCN2022098870-appb-000004
其中，C.E. C为正极活性物质的首次库伦效率，C.E. A为负极活性物质的首次库伦效率，C A为负极活性物质的首次嵌锂容量mAh/g。如此，通过设置补锂孔的孔深下限值，便于补锂孔中能填满补锂剂，可实现正极活性物质容量的充分发挥，有效提升能量密度。
第三方面，本申请提供了一种电极组件，包括正极片、负极片及设于正极片与负极片之间的隔离件；其中，正极片和/或负极片为以上任一项的极片。
上述的电极组件，采用以上的极片，针对不同分布区域补充不同锂，实现定量、精准补锂，有利于提升电池能量密度和寿命。
第四方面，本申请提供了一种二次电池，包括以上的电极组件。
上述的二次电池，采用以上的极片，针对不同分布区域补充不同锂，实现定量、精准补锂，有利于提升电池能量密度和寿命。
第五方面，本申请提供了一种用电装置，包括以上的二次电池。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1为本申请的一些实施例中所述的车辆结构示意图；
图2为本申请的一些实施例中所述的电池的爆炸图；
图3为本申请的一些实施例中所述的极片的局部结构示意图；
图4为本申请的一些实施例中所述的极片的结构剖视图；
图5为本申请的一些实施例中所述的极片制作方法流程图一；
图6为本申请的一些实施例中所述的极片制作方法流程图二。
1000、车辆；100、电池；200、控制器；300、马达；110、箱体；111、第一部分；112、第二部分；120、电池单体；10、极片；11、集流结构；11a、集流体；12、活性层；13、 补锂空间；13a、补锂孔；14、分布区域；14a、第一分布区域；14b、第二分布区域；15、补锂层；16、单面极片。
具体实施方式
下面将结合附图对本申请技术方案的实施例进行详细的描述。以下实施例仅用于更加清楚地说明本申请的技术方案，因此只作为示例，而不能以此来限制本申请的保护范围。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本文中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请；本申请的说明书和权利要求书及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。
在本申请实施例的描述中，技术术语“第一”“第二”等仅用于区别不同对象，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、特定顺序或主次关系。在本申请实施例的描述中，“多个”的含义是两个以上，除非另有明确具体的限定。
在本文中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
在本申请实施例的描述中，术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请实施例的描述中，术语“多个”指的是两个以上(包括两个)，同理，“多组”指的是两组以上(包括两组)，“多片”指的是两片以上(包括两片)。
在本申请实施例的描述中，技术术语“中心”“纵向”“横向”“长度”“宽度”“厚度”“上”“下”“前”“后”“左”“右”“竖直”“水平”“顶”“底”“内”“外”“顺时针”“逆时针”“轴向”“径向”“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请实施例和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请实施例的限制。
在本申请实施例的描述中，除非另有明确的规定和限定，技术术语“安装”“相连”“连接”“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；也可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而 言，可以根据具体情况理解上述术语在本申请实施例中的具体含义。
目前，从市场形势的发展来看，动力电池的应用越加广泛。动力电池不仅被应用于水力、火力、风力和太阳能电站等储能电源系统，而且还被广泛应用于电动自行车、电动摩托车、电动汽车等电动交通工具，以及军事装备和航空航天等多个领域。随着动力电池应用领域的不断扩大，其市场的需求量也在不断地扩增。
本申请人注意到，在锂离子电池首次充电过程中，有机电解液会在石墨等负极表面还原分解，形成固体电解质相界面膜，永久地消耗大量来自正极的锂，造成首次循环的库仑效率偏低，降低了锂离子电池的容量和能量密度。
为了解决循环过程中，因锂的不可逆耗损而导致电池容量和能量密度降低的问题，申请人研究发现，可采用锂带压延等补锂方式，向电池内部增加锂以补充锂离子，以此来提升能量密度和寿命。然而，在涂布过程中，比如转移式涂布，通过钢辊将浆料转移到集流体上，如铜箔或铝箔等，形成一层均匀厚度的涂膜区；接着经过隧道式烘干箱进行烘烤。然而在烘烤过程中，集流体上的涂膜区的边缘的固含量比中间区上升更快，涂膜区的边缘的浆料表面张力大于中间部分的表面张力，浆料向边缘区域流动，导致烤干后的极片出现“厚边”现象。
为了避免极片边缘厚边，通常需对极片边缘进行削薄，比如采用削薄装置或转移涂布机等设备对边缘削薄处理。但削薄后，会导致极片上不同分布区域的活性物质量不同，例如极片的中间大面区和边缘削薄区的活性物质量不同。若在极片上布置相同的补锂量时，由于边缘削薄区中的活性物质脱嵌锂量和中间大面区中的脱嵌量较少，因此在相同补锂量下，会使得削薄区域补锂量太多而出现析锂问题，或者中间大面区域补锂量过少而出现容量损失或者寿命改善不足预期的问题。
基于以上考虑，为了解决因不同分布区域活性物质量不同而导致无法准确补锂的问题，发明人经过深入研究，设计了一种极片，将所述活性层的单位面积活性物质平均重量记为M A，所述分布区域沿所述集流结构的厚度方向投影所涵盖的补锂空间的孔内体积之和记为V0。第一分布区域中的M A小于第二分布区域中的M A，且第一分布区域中所对应的V0小于第二分布区域中所对应的V0。
在设置补锂空间过程中，根据至少两个分布区域中的活性物质平均重量变化，正相关控制各个分布区域所对应的补锂空间的孔内体积之和V0，即第二分布区域中对应的补锂空间内的体积之和较大，第一分布区域中对应补锂空间内的体积之和较小。这样针对不同分布区域补充不同锂，实现定量、精准补锂，避免相同补锂量的前提下，导致第一分布区域补锂量太多而出现析锂问题，或者第二分布区域补锂量过少而出现容量损失或者寿命改善不足 预期的问题，有利于提升电池能量密度和寿命。
本申请实施例公开的电池单体可以但不限用于车辆、船舶或飞行器等用电装置中。可以使用具备本申请公开的电池单体、电池等组成该用电装置的电源系统，这样，针对不同分布区域补充不同锂，实现定量、精准补锂，有利于提升电池能量密度和寿命。
本申请实施例提供一种使用电池作为电源的用电装置，用电装置可以为但不限于手机、平板、笔记本电脑、电动玩具、电动工具、电瓶车、电动汽车、轮船、航天器等等。其中，电动玩具可以包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等，航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
以下实施例为了方便说明，以本申请一实施例的一种用电装置为车辆1000为例进行说明。
请参照图1，图1为本申请一些实施例提供的车辆1000的结构示意图。车辆1000可以为燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混合动力汽车或增程式汽车等。车辆1000的内部设置有电池100，电池100可以设置在车辆1000的底部或头部或尾部。电池100可以用于车辆1000的供电，例如，电池100可以作为车辆1000的操作电源。车辆1000还可以包括控制器200和马达300，控制器200用来控制电池100为马达300供电，例如，用于车辆1000的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池100不仅可以作为车辆1000的操作电源，还可以作为车辆1000的驱动电源，代替或部分地代替燃油或天然气为车辆1000提供驱动动力。
请参照图2，图2为本申请一些实施例提供的电池100的爆炸图。电池100包括箱体110和电池单体120，电池单体120容纳于箱体110内。其中，箱体110用于为电池单体120提供容纳空间，箱体110可以采用多种结构。在一些实施例中，箱体110可以包括第一部分111和第二部分112，第一部分111与第二部分112相互盖合，第一部分111和第二部分112共同限定出用于容纳电池单体120的容纳空间。第二部分112可以为一端开口的空心结构，第一部分111可以为板状结构，第一部分111盖合于第二部分112的开口侧，以使第一部分111与第二部分112共同限定出容纳空间；第一部分111和第二部分112也可以是均为一侧开口的空心结构，第一部分111的开口侧盖合于第二部分112的开口侧。当然，第一部分111和第二部分112形成的箱体110可以是多种形状，比如，圆柱体、长方体等。
在电池100中，电池单体120可以是多个，多个电池单体120之间可串联或并联或混联，混联是指多个电池单体120中既有串联又有并联。多个电池单体120之间可直接串联或并联或混联在一起，再将多个电池单体120构成的整体容纳于箱体110内；当然，电池100也可以是多个电池单体120先串联或并联或混联组成电池100模块形式，多个电池100 模块再串联或并联或混联形成一个整体，并容纳于箱体110内。电池100还可以包括其他结构，例如，该电池100还可以包括汇流部件，用于实现多个电池单体120之间的电连接。
其中，每个电池单体120可以为二次电池100或一次电池100；还可以是锂硫电池100、钠离子电池100或镁离子电池100，但不局限于此。电池单体120可呈圆柱体、扁平体、长方体或其它形状等。
根据本申请的一些实施例，请参照图3，本申请提供了一种极片10。极片10包括：集流结构11与两个活性层12。两个活性层12分别设于集流结构11沿集流结构11的厚度方向的相对两侧面上。集流结构11上设有用于通向一侧活性层12的若干补锂空间13。补锂空间13内容纳有补锂剂。在与补锂空间13相通的活性层12上分布区域14中，活性层12的单位面积活性物质平均重量记为M A。分布区域14沿集流结构11的厚度方向投影所涵盖的补锂空间13内的体积之和记为V0。分布区域14至少包括第一分布区域14a与第二分布区域14b。其中，第一分布区域14a中的M A小于第二分布区域14b中的M A，且第一分布区域14a中所对应的V0小于第二分布区域14b中所对应的V0。
集流结构11是指不仅能承载活性物质，而且还能将电极活性物质产生的电流汇集并输出的构件或零件，该构件或零件中可具有一层或多层结构。集流结构11的材料可有多种选择，比如：可为但不限于铜、铝、镍、不锈钢等金属材料；当然，也可为碳等半导体材料以及导电树脂、钛镍形状记忆合金、覆碳铝箔等复合材料。
活性层12是指涂覆在集流结构11上的活性物质，根据极片10的极性不同，其具体成分不同。比如：正极片上的活性物质可为但不限于钴酸锂、锰酸锂、镍酸锂、磷酸铁锂、三元材料等。负极片上的活性物质可为但不限于石墨、钛酸锂、硅氧化物等。
补锂剂是指能向电池100内部补充锂离子的物质，比如：当极片10为负极片时，补锂剂可为但不限于锂箔、锂粉、硅化锂粉等。当极片10为正极片时，补锂剂可为但不限于Li 2NiO 2、Li 5FeO 4、Li 2O等。另外，补锂剂在补锂空间13中形成的方式可为压延或沉积的方式，其中，沉积方式可为但不限于磁控溅射沉积方式等。
补锂空间13是指集流结构11上具有能容纳补锂剂的空间，比如：孔状或槽状结构；或者，凹状结构等。当补锂空间13为集流结构11上的凹状结构时，集流结构11的表面可呈现波浪形。活性层12背向集流结构11的一侧面上具有多个分布区域14，至少两个分布区域14中单位面积的活性物质平均重量不相同。比如：极片10边缘经过削薄处理后，边缘中单位面积的活性物质的平均重量普遍小于极片10中部分布区域14中的活性物质的平均重量等。其中，影响单位面积的活性物质的平均重量的因素可为但不限于活性物质的类型、活性物质的厚度、活性物质的密实度等。因此，在设置补锂空间13时，以单位面积的活性物质 的平均重量作为参考依据，能更全面考虑影响补锂效果的情形，使得补锂量更为精准。为便于理解，以图3为例，集流结构11的厚度方向为图3中S任一箭头所指的方向。
分布区域14沿集流结构11的厚度方向投影所涵盖的补锂空间13的孔内体积之和应理解为：在同一活性层12中，各个分布区域14在集流结构11的厚度方向上投影能框住部分补锂空间13，而这部分的补锂空间13的孔内体积之和记为V0。补锂空间13的孔内体积的大小能决定该对应的分布区域14所对应的补锂总量。需要说明的是，各个分布区域14所对应的补锂空间13的孔内体积之和的大小，其影响因素可为但不限于补锂空间13的深度、补锂空间13的开口面积、补锂空间13的分布密度等。
补锂空间13能通向活性层12是指：补锂空间13一端与活性层12保持相通，补锂空间13中的补锂剂能渗入至活性层12上，以实现补锂效果。其中，补锂空间13通向活性层12的实现方式可为在集流结构11朝向活性层12的一侧开空间；也可为将补锂空间13的一端延伸至活性层12的内部中等。
补锂空间13内的体积之和是指：一个分布区域14所对应的多个补锂空间13的内部体积总和。而单个补锂空间13的体积大小的确定方式有多种，比如：先获取补锂空间13的开口面积；再获取补锂空间13的深度；最后，将开口面积与深度作乘积，所获取的数据为单个补锂空间13的体积等。
补锂空间13的形状可有多种设计，比如：可以是圆形、方形、菱形、三角形等任意一种或多种。同时，所有的补锂空间13的开口面积可保持一致，也可不一致，如，所有的补锂空间13中，开口面积大小不一等。为使补锂扩散尽可能均匀，补锂空间13的开口面积应尽可能小，比如：当补锂空间13为圆形或者方形时，其直径或宽度大小可为5微米(um)～1毫米(mm)。在一些实施例中，补锂空间13的直径或宽度大小可为30um～200um，比如：补锂空间13的直径或宽度可为但不限于30um、50um、70um、90um、100um、120um、150um、180um、200um。
本申请的极片10中，可在集流结构11的一侧上开设补锂空间13，也可在集流结构11的两侧均开设补锂空间13。若仅在集流结构11的一侧开设补锂空间13时，极片10则具有一侧补锂效果。
在集流结构11上设置补锂空间13，使得补锂空间13与一侧的活性层12内；利用补锂空间13中的补锂剂向电池100内补充锂，抵消循环过程中不可逆锂的损耗，以提高电池100的总容量和能量密度。由于活性层12上至少两个分布区域14中所对应的活性物质平均重量M A不同，因此，本申请根据不同分布区域14中的活性物质平均重量变化，正相关控制各个分布区域14所对应的补锂空间13的孔内体积之和V0，即第二分布区域14b中对应的 补锂空间13内的体积之和较大，第一分布区域14a中对应补锂空间13内的体积之和较小。这样针对不同分布区域14补充不同锂，实现定量、精准补锂，避免相同补锂量的前提下，导致第一分布区域14a补锂量太多而出现析锂问题，或者第二分布区域14b补锂量过少而出现容量损失或者寿命改善不足预期的问题，有利于提升电池100能量密度和寿命。
根据本申请的一些实施例，请参照图4，补锂空间13的深度记为d。补锂空间13所在位置对应的活性层12的厚度记为h。其中，第一分布区域14a中的h小于第二分布区域14b中的h，且第一分布区域14a中所对应的d小于第二分布区域14b中所对应的d。
补锂空间13所在位置对应的活性层12的厚度可理解为：将补锂空间13所在位置沿集流结构11的厚度方向继续延伸至活性层12的表面，贯穿活性层12的路径长度即为对应的活性层12的厚度。
在以活性层12的厚度作为开空间参考时，应尽可能保证集流结构11一侧面上的活性层12均为同一类型的活性物质，且活性层12在集流结构11上的密实度也保证相同等。
在不同分布区域14中，以活性层12的厚度作为参考，将补锂空间13内的体积之和参数的控制转化为对补锂空间13的深度的控制，不仅能实现定量、精准补锂效果，而且还简化补锂空间13的加工工艺，提升极片10制作效率。
根据本申请的一些实施例，补锂空间13的深度d满足如下关系：
Figure PCTCN2022098870-appb-000005
其中，C A为负极活性物质的首次嵌锂容量，毫安时/克(mAh/g)，C C为正极活性物质的首次脱锂容量mAh/g，M C为正极单位面积活性物质的平均重量，克/平方厘米(g/cm 2)，P为单位面积中所有补锂空间13的面积的占比。
不等式中，3860为锂金属的理论比容量，其单位为mAh/g；0.534为锂金属的密度，其单位克/立方厘米(g/cm 3)；10000为单位换算值。另外，单位面积中所有补锂空间13孔面积的占比应理解为：在单位面积中，所有补锂空间13的横截面面积之和与“1”之间的比值。
在补锂过程中，若补锂过量，容易导致负极侧循环过程中产生析锂现象，为此，在设计补锂空间13的深度时，需设置深度的上限值。另外，若在制作过程中，补锂空间13的深度不满足上述不等式时，可通过增加负极单位面积活性物质的平均重量，比如：在对应的分布区域14上涂覆活性物质等，以使补锂空间13的深度满足该不等式关系。
通过设置补锂空间13的深度上限值，避免补充过量锂而导致负极侧循环过程产生析锂，有利于提升电池100的安全性能。
根据本申请的一些实施例，单位面积中所有补锂空间13开口面积的占比P满足如下关系：10％≤P≤50％。
单位面积中，补锂空间13的开口面积的占比不宜过大，若补锂空间13面积所占 比过大，则会导致集流结构11上镂空部分较多，严重影响其自身的电子传导功能。在一些实施例中，单位面积中所有补锂空间13开口面积的占比P可为但不限于10％、15％、20％、25％、30％、35％、40％、45％、50％等。
将单位面积中所有补锂空间13开口面积的占比P控制在10％与50％之间，在保证满足具有足够容纳补锂剂的空间下，合理控制补锂空间13的开口面积占比，确保集流结构11的电子传导功能稳定。
根据本申请的一些实施例，补锂空间13的深度d满足如下关系：
Figure PCTCN2022098870-appb-000006
其中，C.E. C为正极活性物质的首次库伦效率，C.E. A为负极活性物质的首次库伦效率，C A为负极活性物质的首次嵌锂容量mAh/g。
正极活性物质的首次库伦效率为正极活性物质的首次嵌锂容量mAh/g与正极活性物质的首次脱锂容量mAh/g之比。负极活性物质的首次库伦效率为负极活性物质的首次脱锂容量mAh/g与负极活性物质的首次嵌锂容量mAh/g之比。其中，首次脱嵌锂容量可以通过制备纽扣电池来测试，例如：正负极按常规配方配置浆料，单面涂布极片10，裁成扣电小圆片，和锂金属片组成扣电半电池。正极极片采用0.1C/0.1C充放电倍率测试，正极材料扣电先充后放，首次充电容量即为正极活性物质的首次脱锂容量，首次放电容量即为正极活性物质的首次嵌锂容量；负极极片采用0.1C/0.05C充放电倍率测试，负极材料扣电先放后充，首次放电容量即为负极活性物质的首次嵌锂容量，首次充电容量即为负极活性物质的首次脱锂容量。
当补锂空间13的深度d大于或等于
Figure PCTCN2022098870-appb-000007
时，能保证正极活性物质的容量充分发挥，有效提升电池100容量和能量密度。同时，随着深度d进一步增加，补锂量也随之增加。虽然此时正极活性物质容量发挥已到达极限不会再进一步提升，但能有效提升循环寿命。
补锂空间13的深度d若同时满足大于或等于
Figure PCTCN2022098870-appb-000008
且小于或等于
Figure PCTCN2022098870-appb-000009
时，电池100的补锂效果为较佳。若补锂空间13的深度d均无法同时满足大于或等于
Figure PCTCN2022098870-appb-000010
且小于或等于
Figure PCTCN2022098870-appb-000011
时，则应优先控制补锂空间13的深度d满足小于或等于
Figure PCTCN2022098870-appb-000012
当然，在此情形下，可通过增加负极单位面积活性物质平均重量，以控制补锂空间13的深度d同时满足以上两个不等式。
通过设置补锂空间13的深度下限值，便于补锂空间13中能填满补锂剂(如金属锂等)，可实现正极活性物质容量的充分发挥，有效提升能量密度。
根据本申请的一些实施例，请参照图4，在至少一侧的活性层12中，补锂空间13间隔排布，且任意相邻两个补锂空间13之间的间距均相等。
任意相邻两个补锂空间13之间的间距均相等可理解为：集流结构11一侧上的补锂空间13为均匀间隔排布，即补锂空间13的分布密度为一定。此时，各个分布区域14中所对应的补锂空间13内的体积之和大小其主要取决于补锂空间13的深度，这样在控制V0与M A之间变化关系时可有效转化为d与h之间变化关系。
在至少一侧的活性层12中，则说明本申请的极片10中，可仅一侧活性层12中具有若干补锂空间13；当然，也可在两侧的活性层12上均对应设置若干补锂空间13。
在任一侧的活性层12中，将补锂空间13均匀分布，便于仅通过控制补锂空间13的深度，即可实现定量、精准补锂效果；同时，均匀排布补锂空间13，便于补锂扩散均匀，使得电池100的性能更佳。
根据本申请的一些实施例，请参照图4，集流结构11沿集流结构11的厚度方向包括至少一个集流体11a。在设有活性层12的集流体11a中，至少一个贯穿设有补锂空间13。
集流体11a是指不仅能承载活性物质，而且还能将电极活性物质产生的电流汇集并输出的构件或零件，是构成集流结构11的核心结构。集流体11a的数量可为一个，也可为多个。当集流体11a为一个时，两个活性层12则设于同一集流体11a的相对两侧面上；当集流体11a为多个时，两个活性层12则分别设置在位于集流结构11的厚度方向上最外两端的集流体11a上。另外，集流体11a为多个时，多个集流体11a沿集流结构11的厚度方向层叠设置。
补锂空间13在集流体11a上设计状态有多种，比如：当集流体11a为一个时，集流上贯穿设有的补锂空间13可朝单侧延伸设置；或者，一部分补锂空间13朝一侧活性层12延伸，另一部分补锂空间13朝另一侧的活性层12延伸。当集流体11a为多个时，仅一个集流体11a上贯穿设有补锂空间13，且该补锂空间13朝对应的活性层12延伸；或者，位于最外端的两个集流体11a上均贯穿设有补锂空间13等。
将集流结构11设计成至少一个集流体11a，不仅便于电子传导，而且方便在集流结构11上开孔，使得补锂剂能稳定沉积在补锂空间13中。
根据本申请的一些实施例，请参照图4，集流体11a包括两个。两个活性层12分别对应设于两个集流体11a相互背向的一侧面。两个集流体11a上均贯穿设有补锂空间13。
两个集流体11a上贯穿补锂空间13时，各个集流体11a上的补锂空间13的一端 延伸至对应的活性层12内部。补锂空间13在集流体11a上的分布可有多种，比如：补锂空间13均匀分布在集流体11a上；或者，补锂空间13的分布密度可根据活性层12的厚度不同而分布，如，厚的活性层12下对应分布较多补锂空间13，薄的活性层12下对应分布较少补锂空间13。
两个集流体11a上的补锂空间13之间分布对应关系也有多种，比如：一个集流体11a上补锂空间13的分布与另一个集流体11a上补锂空间13的分布完全错开，即一侧的补锂空间13与另一侧的补锂空间13不相通；或者，一个集流体11a上补锂空间13的分布与另一个集流体11a上补锂空间13的分布完全对齐，即一侧的补锂空间13与另一侧的补锂空间13保持相通等。当两个集流体11a上补锂空间13保持相互相通状态时，两个集流体11a上的补锂空间13中的补锂剂可相互共用，即一侧补锂空间13中的补锂剂可用于另一侧活性层12的补锂。
两个集流体11a之间的连接方式可为但不限于焊接、粘接等。比如：在制作过程中，涂覆有活性层12的两个集流体11a，以具有补锂空间13的一侧相互贴合；贴合后，利用焊接或粘接等方式将两个集流体11a的周向边缘连接等。
在两个集流体11a上分别贯穿设有补锂空间13，使得两侧的活性层12均能实现有效补锂，进一步提升电池100的能量密度和循环寿命。
根据本申请的一些实施例，请参照图4，集流结构11还包括至少一个补锂层15。补锂层15位于两个集流体11a之间。
补锂层15是指能向电池100内部补充锂离子的物质，比如：当极片10为负极片时，补锂层15可为但不限于金属锂层等。当极片10为正极片时，补锂层15可为但不限于Li 2NiO 2、Li 5FeO 4、Li 2O等
补锂层15在两个集流体11a之间可为一个，也可为多个。当补锂层15为两个，一个补锂层15贴合在一个集流体11a背向活性层12的一侧面上；另一个补锂层15贴合在另一个集流体11a背向活性层12的一侧面上。
在两个集流体11a之间设置至少一个补锂层15，增加补锂量，能有效地提升电池100的循环寿命。
根据本申请的一些实施例，请参照图4，补锂空间13为补锂孔13a。补锂孔13a沿集流结构11的厚度方向延伸至任一侧的活性层12内。
补锂孔13a沿集流结构11的厚度方向延伸至活性层12内应理解为，补锂孔补锂空间13一端位于活性层12的内部，且不贯穿活性层12，即类似盲孔结构。
将补锂空间13设计成补锂孔13a，并将补锂孔13a一端延伸至活性层12内部， 这样不仅有利于简化极片10的制作工序，而且还更有利于控制不同分布区域14下对应的补锂剂量，实现更为精准的补锂。
根据本申请的一些实施例，请参照图4，第一分布区域14a环绕第二分布区域14b的外围延伸设置。
第一分布区域14a相对靠近极片10的边缘处，第二分布区域14b相对靠近极片10的中部处；同时，第一分布区域14a呈线环状结构。
极片10上靠边缘处的活性物质平均重量M A小于极片10上靠近中部处的活性物质平均重量M A，如此设计，有利于解决极片10边缘因过厚而出现鼓边的问题。
根据本申请的一些实施例，请参照图5，一种极片10制作方法，包括如下步骤：
S100、提供两个单面极片1610，其中，单面极片1610包括集流体11a及设于集流体11a一侧的活性层12；
S200、在至少一个单面极片1610上，对集流体11a开设延伸至活性层12内的补锂孔13a，并控制活性层12上至少两个分布区域14中单位面积活性物质平均重量M A与对应的补锂孔13a的孔内体积之和V0满足：第一分布区域14a中的M A小于第二分布区域14b中的M A，且第一分布区域14a中所对应的V0小于第二分布区域14b中所对应的V0，其中，分布区域14包括第一分布区域14a和第二分布区域14b；
S300、在全部补锂孔13a中沉积补锂剂；
S400、将两个单面极片1610上背向活性层12的一侧面相互贴合。
在步骤S100中，单面极片1610可大致理解成极片10的一半结构，即包括集流体11a和涂覆在集流体11a一侧面的活性层12，此时该集流体11a的另一侧不涂覆活性层12。单面极片1610的制作工艺可不包含在本申请的极片10制作方法中，由供应商或由其他工序中直接完成；当然，单面极片1610的制作工艺也可包含在本申请的极片10制作方法中，比如：在集流体11a一侧面上涂布有活性物质；涂布后，对集流体11a进行辊压(冷压)压实，以使粉体的重排和致密化。另外，为避免单面极片1610边缘厚边，对单面极片1610的边缘进行削薄处理，此时活性层12上不同分布区域14中的活性物质的平均重量不等。
在步骤S200中，在集流体11a上打孔的方式有多种，比如：激光打孔、辊钉扎孔等方式。
在步骤S300中，在补锂孔13a中沉积补锂剂时，理应将补锂孔13a内沉积满补锂剂，即孔内的补锂剂能与补锂孔13a在集流体11a上的一端齐平。补锂剂的沉积方式可为但不限于锂带压延、磁控溅射沉积等方式。
在步骤S400中，两个单面极片1610背向活性层12的一侧面相互贴合，可理解 为打孔的单面极片1610的一面相互贴合组装。这样在后续电极组件制作时，单面极片1610上的活性层12则分别面向隔离件(如隔膜)。
以单向极片10相互贴合方式制作所需极片10，大大简化制作工艺；同时，也便于在极片10内开孔，保证补锂剂稳定沉积在补锂孔13a中，以实现定量、精准的补锂效果。由于活性层12上不同分布区域14中所对应的活性物质平均重量M A，因此，本申请根据不同分布区域14中的活性物质平均重量变化，正相关控制各个分布区域14所对应的补锂孔13a的孔内体积之和V0，即第二分布区域14b中对应的补锂孔13a的孔内体积之和相对较大，第一分布区域14a中对应补锂孔13a的孔内体积之和相对较小。这样针对不同分布区域14补充不同锂，实现定量、精准补锂，避免相同补锂量的前提下，导致第一分布区域14a(如削薄区域等)补锂量太多而出现析锂问题，或者第二分布区域14b(如大面区域等)补锂量过少而出现容量损失或者寿命改善不足预期的问题，有利于提升电池100能量密度和寿命。
根据本申请的一些实施例，请参照图6，S200、控制活性层12上不同分布区域14中单位面积活性物质平均重量M A与对应的补锂孔13a的孔内体积之和V0呈正相关变化的步骤，包括：
S210、获取不同分布区域14中活性层12的厚度h，
S220、在集流体11a均匀开设若干补锂孔13a；
S230、控制各个分布区域14在集流体11a上投影区域中的补锂孔13a的深度d，以使第一分布区域14a中的h小于第二分布区域14b中的h，且第一分布区域14a中所对应的d小于第二分布区域14b中所对应的d。
在步骤S220中，均匀开设若干补锂孔13a应理解为：任意相邻两个补锂孔13a之间的孔距均相等。由于各个分布区域14所对应的补锂孔13a的孔内体积之和的大小，其影响因素可为但不限于补锂孔13a的孔深、补锂孔13a的分布密度等，因此，控制补锂孔13a的分布密度为一定，此时，各个分布区域14中所对应的补锂孔13a的孔内体积之和大小其主要取决于补锂孔13a的孔深，这样在控制V0与M A之间变化关系时可有效转化为d与h之间变化关系。
以活性层12的厚度作为参考，将补锂孔13a的孔内体积之和参数的控制转化为对补锂孔13a的孔深的控制，不仅能实现定量、精准补锂效果，而且还简化补锂孔13a的加工工艺，提升极片10制作效率。
根据本申请的一些实施例，补锂孔13a的深度d满足如下关系：
Figure PCTCN2022098870-appb-000013
其中，C A为负极活性物质的首次嵌锂容量mAh/g，C C为正极活性物质的首次脱锂 容量mAh/g，M C为正极单位面积活性物质的平均重量g/cm 2，P为集流结构11上单位面积中所有补锂孔13a孔面积的占比。
在补锂过程中，若补锂过量，容易导致负极侧循环过程中产生析锂现象，为此，在设计补锂孔13a的孔深时，需设置孔深的上限值。另外，若在制作过程中，补锂孔13a的孔深不满足上述不等式时，可通过增加负极单位面积活性物质的平均重量，比如：在对应的分布区域14上涂覆活性物质等，以使补锂孔13a的孔深满足该不等式关系。
通过设置补锂孔13a的孔深上限值，避免补充过量锂而导致负极侧循环过程产生析锂，有利于提升电池100的安全性能。
根据本申请的一些实施例，补锂孔13a的深度d满足如下关系：
Figure PCTCN2022098870-appb-000014
其中，C.E. C为正极活性物质的首次库伦效率，C.E. A为负极活性物质的首次库伦效率，C A为负极活性物质的首次嵌锂容量mAh/g。
当补锂孔13a的深度d大于或等于
Figure PCTCN2022098870-appb-000015
时，能保证正极活性物质的容量充分发挥，有效提升电池100容量和能量密度。同时，随着深度d进一步增加，补锂量也随之增加。虽然此时正极活性物质容量发挥已到达极限不会再进一步提升，但能有效提升循环寿命。
补锂孔13a的深度d若同时满足大于或等于
Figure PCTCN2022098870-appb-000016
且小于或等于
Figure PCTCN2022098870-appb-000017
时，电池100的补锂效果为较佳。若补锂孔13a的深度d均无法同时满足大于或等于
Figure PCTCN2022098870-appb-000018
且小于或等于
Figure PCTCN2022098870-appb-000019
时，则应优先控制补锂孔13a的深度d满足小于或等于
Figure PCTCN2022098870-appb-000020
当然，在此情形下，可通过增加负极单位面积活性物质平均重量，以控制补锂孔13a的深度d同时满足以上两个不等式。
通过设置补锂孔13a的孔深下限值，便于补锂孔13a中能填满补锂剂(如金属锂等)，可实现正极活性物质容量的充分发挥，有效提升能量密度。
为了使本申请的目的、技术方案及优点更加简洁明了，本申请用以下具体实施例进行说明，但本申请绝非仅限于这些实施例。以下所描述的实施例仅为本申请较好的实施例，可用于描述本申请，不能理解为对本申请的范围的限制。应当指出的是，凡在本申请的精神和原则之内所做的任何修改、等同替换和改进等，均应包含在本申请的保护范围之内。
为了更好地说明本申请，下面结合实施例对本申请内容作进一步说明。以下为具 体实施例。
相同的化学体系下(即正极片和负极片的集流体11a类型相同)，补锂孔13a深度d对电池100的循环圈数的影响。
对比例1
负极片：
以高硅作为负极集流体11a，负极边缘的第一分布区域14a中的单位面积活性物质平均重量M A为0.0075g/cm 2，负极边缘的第二分布区域14b中的单位面积活性物质平均重量M A为0.0100g/cm 2，活性物质的首次嵌锂容量(充电克容量)C A为800mAh/g，负极首效(首次放电容量/首次充电容量)为80％。
将单位面积中补锂孔13a的孔面积占比P设置为50％，按照
Figure PCTCN2022098870-appb-000021
Figure PCTCN2022098870-appb-000022
不等式，计算出第二分布区域14b所对应的补锂孔13a的深度d范围为7.8um～13.6um，第一分布区域14a所对应的补锂孔13a的深度d范围为5.8um～7.0um。
本实施例第二分布区域14b所对应的孔深设计为0um(即不打孔)，第一分布区域14a所对应的孔深设计为0um(即不打孔)，但为了便于对比，对比例1中的补锂孔13a的孔面积占比P依然记为50％。
正极片：
以NCM(由镍钴锰三种材料组成的三元材料)作为正极集流体11a，正极边缘的第一分布区域14a中的单位面积活性物质平均重量M C为0.0240g/cm 2，正极边缘的第二分布区域14b中的单位面积活性物质平均重量M C为0.0300g/cm 2，活性物质的首次嵌锂容量(充电克容量)C C为220mAh/g，正极首效(首次放电容量/首次充电容量)为90％。
实施例1
与对比例1基本相同，区别仅在于：负极片中，第二分布区域14b所对应的补锂孔13a的案例深度d设计为10um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为10um。
实施例2
与对比例1基本相同，区别仅在于：负极片中，第二分布区域14b所对应的补锂孔13a的案例深度d设计为6.5um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为6.5um。
实施例3
与对比例1基本相同，区别仅在于：负极片中，第二分布区域14b所对应的补锂孔13a的案例深度d设计为10um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为6.5um。
各实施例和对比例的部分参数如下表1-1和表1-2所示。
将上述对比例和实施例制备的电池100进行常温循环性能测试，结果如表1-2所示。具体测试步骤如下：
在25℃时，将电池100以1C恒流充电至4.25V，然后恒压充电至电流为0.05C，再用1C恒流放电至2.8V，此时为首次循环，按照上述条件进行循环充电/放电，将电池100容量保持率衰减至80％时电池100的循环圈数。
表1-1
Figure PCTCN2022098870-appb-000023
表1-2
Figure PCTCN2022098870-appb-000024
从表1-2可知，在极片10上开设有补锂孔13a的电池100，相对于对比例1不开孔的电池100，其正极克容量发挥均有效提升。同时，实施例2和实施例3中相对于对比例1的电池100，其80％容量保持率循环圈数均有所提升。而实施例1的循环圈数则有所降低，这说明补锂孔13a的孔深并不是越大越高，需要保证小于或等于不同分布区域14的孔深最大值，过深则循环过程中容易产生析锂。
实施例1～2和实施例3对比可知，当补锂孔13a的深度d同时满足
Figure PCTCN2022098870-appb-000025
不等式时，电池100的正极克容量发挥和循环圈数的性能为最佳。
另外，补锂孔13a的深度d随不同分布区域14正相关变化时，比如：第二分布区域14b中深度d设计较大，第一分布区域14a中深度d设计较小等，电池100的正极克容量发挥和循环圈数的数据为最好。
不同的化学体系下(即正极片和负极片的集流体11a类型相同)，补锂孔13a深度d对电池100的循环圈数的影响。
对比例2
与对比例1基本相同，区别至少在于：负极片中，单位面积中补锂孔13a的孔面积占比P记为50％；第二分布区域14b所对应的补锂孔13a的案例深度d设计为5um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为4um。
对比例3
与对比例2基本相同，区别至少在于：第二分布区域14b所对应的补锂孔13a的案例深度d设计为20um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为10um。
对比例4
与对比例1基本相同，区别至少在于：负极片中，负极集流体11a为低硅。
对比例5
与对比例1基本相同，区别至少在于：负极片中，负极集流体11a为石墨。
对比例6
与对比例1基本相同，区别至少在于：正极片中，正极集流体11a为LFP(LiFePO4磷酸铁锂)。
实施例4
与上述实施例3基本相同，区别至少在于：负极片中，单位面积中补锂孔13a的孔面积占比P记为30％；第二分布区域14b所对应的补锂孔13a的案例深度d设计为15um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为10.5um。
实施例5
与上述实施例3基本相同，区别至少在于：负极片中，单位面积中补锂孔13a的孔面积占比P记为10％；第二分布区域14b所对应的补锂孔13a的案例深度d设计为40um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为31um。
实施例6
与上述实施例3基本相同，区别至少在于：负极片中，单位面积中补锂孔13a的 孔面积占比P记为70％；第二分布区域14b所对应的补锂孔13a的案例深度d设计为7um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为4.5um。
实施例7
与上述实施例3基本相同，区别至少在于：负极边缘的第一分布区域14a中的单位面积活性物质平均重量M A为0.0068g/cm 2，负极边缘的第二分布区域14b中的单位面积活性物质平均重量M A为0.0090g/cm 2，第二分布区域14b所对应的补锂孔13a的案例深度d设计为5um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为1.0um。
实施例8
与上述实施例3基本相同，区别至少在于：负极边缘的第一分布区域14a中的单位面积活性物质平均重量M A为0.0120g/cm 2，负极边缘的第二分布区域14b中的单位面积活性物质平均重量M A为0.0150g/cm 2，第二分布区域14b所对应的补锂孔13a的案例深度d设计为25um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为20.0um。
实施例9
与对比例4基本相同，区别至少在于：负极片中，单位面积中补锂孔13a的孔面积占比P记为50％，第二分布区域14b所对应的补锂孔13a的案例深度d设计为8um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为5.0um。
实施例10
与对比例5基本相同，区别至少在于：负极片中，单位面积中补锂孔13a的孔面积占比P记为50％，第二分布区域14b所对应的补锂孔13a的案例深度d设计为7um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为4.0um。
实施例11
与对比例6基本相同，区别至少在于：负极片中，单位面积中补锂孔13a的孔面积占比P记为50％，第二分布区域14b所对应的补锂孔13a的案例深度d设计为4.0um，第一分布区域14a所对应的补锂孔13a的案例深度d设计为3.0um。
各实施例和对比例的部分参数如下表2-1和表2-2所示。
将上述对比例和实施例制备的电池100进行常温循环性能测试，结果如表2-2所示。
表2-1
Figure PCTCN2022098870-appb-000026
从表2-2可知，实施例3～实施例6和对比例2对比可知，在相同化学体系下，当补锂孔13a的孔深同时满足上述两个不等式且深度d随不同分布区域14厚度不同而变化时，单位面积中补锂孔13a的孔面积占比P的提升，对于正极克容量发挥影响不大(即正极克容量发挥已达极限不会再提升)，但对于循环圈数会有所增加，即能提升电池100的循环寿命。
实施例7～实施例8和对比例3对比可知，当补锂孔13a的孔深无法同时满足上述两个不等式时，则需优先将补锂孔13a的深度d满足小于或等于
Figure PCTCN2022098870-appb-000027
同时，通过增加负极单位面积活性物质平均重量M A，可将孔深度d调整至同时满足上述两个不等式，且正极克容量发挥和循环圈数会有显著提升。
实施例9与对比例4、实施例10与对比例5、以及实施例11与对比例6中均可知，不论在何种化学体系下，将补锂孔13a的深度d同时满足以上两个不等式中，且深度d的大小随不同分布区域14中负极活性层12厚度正相关变化时，电池100的循环圈数会有明显提升，即能有效提升电池100的循环寿命。
表2-2
Figure PCTCN2022098870-appb-000028
根据本申请的一些实施例，本申请提供了一种电极组件，电极组件包括正极片、负极片及设于正极片与负极片之间的隔离件。其中，正极片和/或负极片为以上任一方案中的极片10。
根据本申请的一些实施例，本申请提供了一种二次电池100，电池100包括以上方案中的电极组件。
根据本申请的一些实施例，本申请提供了一种用电装置，包括以上方案中的二次电池100。
根据本申请的一些实施例，本申请还提供了一种长寿命负极及电池100，实现定量精准补锂，有效进行补锂量控制防呆，具体实施方式如下：
1、对单面负极片涂布并进行冷压；
2、单面负极片通过激光打孔、辊钉扎孔等方式，进行不同区域不同深度的打孔；
3、采用锂带压延或磁控溅射沉积等方式在孔洞内定向沉积金属锂；
4、将上述负极片按“正极/隔膜/单面负极片/单面负极片/隔膜/正极”的顺序堆叠或卷 绕组装成电池100，其中每两个单面负极片间，打孔补锂的一面贴合组装，负极活性物质的一面分别面向隔膜。
为实现精准补锂调控，负极片不同区域的孔深度d设计需满足如下关系：
Figure PCTCN2022098870-appb-000029
孔深度d符合式1-1的最小值时，将补锂孔13a填满金属锂，可实现正极克容量的充分发挥，有效提升能量密度，随着孔深度d进一步增加，补锂量增加，正极克容量发挥已达极限不会再提升，但可有效地提升循环寿命。
同时，为避免补充过量锂而使负极侧循环过程产生析锂，负极片不同区域的孔洞深度d设计需满足如下关系：
Figure PCTCN2022098870-appb-000030
孔深度d需同时满足式1-1和式1-2。当式1-1和式1-2无法同时满足时，孔洞深度d需优先满足式1-2，以避免析锂出现安全风险。另外，通过增加负极单位面积活性物质平均重量M A，可以将孔深度d调整至同时满足式1-1和式1-2。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围，其均应涵盖在本申请的权利要求和说明书的范围当中。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (18)

  1. 一种极片，包括：
    集流结构；
    两个活性层，分别设于所述集流结构沿所述集流结构的厚度方向的相对两侧面上，所述集流结构上设有用于通向一侧所述活性层的若干补锂空间，所述补锂空间内容纳有补锂剂；
    在与所述补锂空间相通的所述活性层上分布区域中，所述活性层的单位面积活性物质平均重量记为M A，所述分布区域沿所述集流结构的厚度方向投影所涵盖的补锂空间内的体积之和记为V0，所述分布区域至少包括第一分布区域与第二分布区域；
    所述第一分布区域中的M A小于所述第二分布区域中的M A，且所述第一分布区域中所对应的V0小于所述第二分布区域中所对应的V0。
  2. 根据权利要求1所述的极片，其中，所述补锂空间的深度记为d，所述补锂空间所在位置对应的所述活性层的厚度记为h；
    所述第一分布区域中的h小于所述第二分布区域中的h，且所述第一分布区域中所对应的d小于所述第二分布区域中所对应的d。
  3. 根据权利要求2所述的极片，其中，所述补锂空间的深度d满足如下关系：
    Figure PCTCN2022098870-appb-100001
    C A为负极活性物质的首次嵌锂容量mAh/g，C C为正极活性物质的首次脱锂容量mAh/g，M C为正极单位面积活性物质的平均重量g/cm 2，P为所述集流结构上单位面积中所有补锂空间的开口面积的占比。
  4. 根据权利要求3所述的极片，其中，单位面积中所有补锂空间的开口面积的占比P满足如下关系：
    10％≤P≤50％。
  5. 根据权利要求2-4任一项所述的极片，其中，所述补锂空间的深度d满足如下关系：
    Figure PCTCN2022098870-appb-100002
    C.E. C为正极活性物质的首次库伦效率，C.E. A为负极活性物质的首次库伦效率，C A为负极活性物质的首次嵌锂容量mAh/g。
  6. 根据权利要求2-5任一项所述的极片，其中，在至少一侧的所述活性层中，所述补锂空间间隔排布，且任意相邻两个所述补锂空间之间的间距均相等。
  7. 根据权利要求1-6任一项所述的极片，其中，所述集流结构沿所述集流结构的厚度方向包括至少一个集流体，在设有所述活性层的集流体中，至少一个贯穿设有所述补锂空间。
  8. 根据权利要求7所述的极片，其中，所述集流结构包括两个所述集流体，两个所述活性层分别对应设于两个所述集流体上相互背向的两个侧面上，两个所述集流体上均贯穿设有所述补锂空间。
  9. 根据权利要求7所述的极片，其中，所述集流结构还包括至少一个补锂层，所述补锂层位于两个所述集流体之间。
  10. 根据权利要求1-9任一项所述的极片，其中，所述补锂空间为补锂孔，所述补锂孔沿所述集流结构的厚度方向延伸至任一侧的所述活性层内。
  11. 根据权利要求1-9任一项所述的极片，其中，所述第一分布区域环绕所述第二分布区域的外围延伸设置。
  12. 一种极片制作方法，包括如下步骤：
    步骤S100、提供两个单面极片，其中，所述单面极片包括集流体及设于所述集流体一侧的活性层；
    步骤S200、在至少一个所述单面极片上，对所述集流体开设延伸至所述活性层内的补锂孔，并控制所述活性层上至少两个分布区域中单位面积活性物质平均重量M A与对应的补锂孔的孔内体积之和V0满足：第一分布区域中的M A小于第二分布区域中的M A，且所述第一分布区域中所对应的V0小于所述第二分布区域中所对应的V0，其中，所述分布区域包括所述第一分布区域和所述第二分布区域；
    步骤S300、在所述补锂孔中沉积补锂剂；
    步骤S400、将两个所述单面极片上背向所述活性层的一侧面相互贴合。
  13. 根据权利要求12所述的极片制作方法，其中，步骤S200中包括：
    步骤S210、获取不同分布区域中所述活性层的厚度h；
    步骤S220、在所述集流体均匀开设若干所述补锂孔；
    步骤S230、控制各个所述分布区域在所述集流体上投影区域中的补锂孔的深度d，以使所述第一分布区域中的h小于所述第二分布区域中的h，且所述第一分布区域中所对应的d小于所述第二分布区域中所对应的d。
  14. 根据权利要求13所述的极片制作方法，其中，所述补锂孔的深度d满足如下关系：
    Figure PCTCN2022098870-appb-100003
    C A为负极活性物质的首次嵌锂容量mAh/g，C C为正极活性物质的首次脱锂容量mAh/g，M C为正极单位面积活性物质的平均重量g/cm 2，P为所述集流结构上单位面积中所有补锂孔孔面积的占比。
  15. 根据权利要求13或14所述的极片制作方法，其中，所述补锂孔的深度d满足如下 关系：
    Figure PCTCN2022098870-appb-100004
    C.E. C为正极活性物质的首次库伦效率，C.E. A为负极活性物质的首次库伦效率，C A为负极活性物质的首次嵌锂容量mAh/g。
  16. 一种电极组件，包括正极片、负极片及设于所述正极片与所述负极片之间的隔离件；
    所述正极片和/或所述负极片为权利要求1-11任一项所述的极片。
  17. 一种二次电池，包括权利要求16所述的电极组件。
  18. 一种用电装置，包括权利要求17所述的二次电池。
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