WO2022198672A1 - 电极组件、电池单体、电池及用电设备 - Google Patents

电极组件、电池单体、电池及用电设备 Download PDF

Info

Publication number
WO2022198672A1
WO2022198672A1 PCT/CN2021/083417 CN2021083417W WO2022198672A1 WO 2022198672 A1 WO2022198672 A1 WO 2022198672A1 CN 2021083417 W CN2021083417 W CN 2021083417W WO 2022198672 A1 WO2022198672 A1 WO 2022198672A1
Authority
WO
WIPO (PCT)
Prior art keywords
active material
electrode active
negative electrode
material layer
positive
Prior art date
Application number
PCT/CN2021/083417
Other languages
English (en)
French (fr)
Inventor
白子瑜
上官会会
杜鑫鑫
胡洋
唐代春
Original Assignee
宁德时代新能源科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
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 PCT/CN2021/083417 priority Critical patent/WO2022198672A1/zh
Priority to CN202180064709.6A priority patent/CN116325278A/zh
Priority to EP21809893.7A priority patent/EP4089757B1/en
Priority to US17/543,850 priority patent/US20220311054A1/en
Publication of WO2022198672A1 publication Critical patent/WO2022198672A1/zh

Links

Images

Classifications

    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • 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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/209—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for prismatic or rectangular cells
    • 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
    • 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
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the field of battery technology, and in particular, to an electrode assembly, a battery cell, a battery, an electrical device, and a method and device for manufacturing the electrode assembly.
  • Lithium precipitation is one of the main factors affecting the electrical performance and safety performance of the battery. Once lithium precipitation occurs in the battery, it will not only reduce the electrical performance of the battery, but also easily form dendrites with the accumulation of lithium precipitation. The crystal may pierce the separator, causing a short circuit in the battery, causing a safety hazard.
  • Embodiments of the present application provide an electrode assembly, a battery cell, a battery, an electrical device, and a manufacturing method and device for the electrode assembly, so as to effectively reduce the risk of lithium precipitation in the battery.
  • an embodiment of the present application provides an electrode assembly for being accommodated in a casing, the electrode assembly includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and the negative electrode sheet are stacked and wound around a winding axis ; the electrode assembly includes abutting areas on both sides of its thickness center plane for abutting with the casing and a non-abutting area not abutting with the casing, the thickness center plane being perpendicular to the the thickness direction of the electrode assembly and passing through the winding axis; the negative electrode sheet includes a plurality of first negative electrode active material layers located in the abutting area and stacked along the thickness direction, and a plurality of first negative electrode active material layers located in the non-abutting area and a plurality of second negative electrode active material layers stacked along the thickness direction; the positive electrode sheet includes a plurality of first positive electrode active material layers located in the abutting region and stacked along the thickness direction and a plurality of first positive electrode active material layers located
  • the lithium ions extracted from the positive electrode cannot enter the negative electrode, the lithium ions can only be precipitated on the surface of the negative electrode, thereby forming a gray substance, that is, lithium precipitation.
  • the active material capacity per unit area of the second negative electrode active material layer in the non-abutting region that does not abut against the casing meets the design requirements, that is, the active material capacity per unit area of the second negative electrode active material layer in the non-abutting region reaches the third A preset value makes it difficult for the second negative electrode active material layer in the non-contact area to have lithium precipitation.
  • the active material capacity per unit area of the first negative electrode active material layer located in the abutting region is greater than the active material capacity per unit area of the second negative electrode active material layer located in the non-abutting region, that is, the active material per unit area of the first negative electrode active material layer
  • the capacity is greater than the first preset value, it is equivalent to increasing the capacity of the active material per unit area of the first negative electrode active material layer, and the first negative electrode active material layer can receive the lithium ions protruded from the first positive electrode active material layer, against the The possibility of lithium precipitation in the first negative electrode active material layer of the region is small, so that the risk of lithium precipitation caused by the extrusion of the electrolyte solution when the abutting region and the casing are abutted can be effectively reduced.
  • the active material capacity per unit area of the second positive electrode active material layer in the non-abutting region that does not abut against the casing meets the design requirements, that is, the active material capacity per unit area of the second positive electrode active material layer in the non-abutting region reaches the third
  • the two preset values make the second negative electrode active material layer in the non-abutting region less likely to cause lithium precipitation.
  • the active material capacity per unit area of the first positive electrode active material layer located in the abutting region is smaller than the active material capacity per unit area of the second positive electrode active material layer located in the non-abutting region, that is, the active material per unit area of the first positive electrode active material layer
  • the capacity is less than the second preset value, which is equivalent to reducing the active material capacity per unit area of the first positive electrode active material layer, and the first negative electrode active material layer can accept the lithium ions released from the first positive electrode active material layer.
  • the possibility of lithium precipitation in the first negative electrode is small, so that the risk of lithium precipitation caused by the extrusion of the electrolyte solution when the abutting area and the casing are in abutment can be effectively reduced.
  • the gram capacity of the active material of the first negative electrode active material layer is greater than the gram capacity of the active material of the second negative electrode active material layer; and/or, the first positive electrode active material The gram capacity of the active material of the substance layer is smaller than the gram capacity of the active material of the second positive electrode active material layer.
  • the active material capacity per unit area of the first negative electrode active material layer in the abutment area can be increased, so that the The unit area capacity of one negative electrode active material layer is greater than the unit area capacity of the second negative electrode active material layer in the non-abutting area; and/or, by reducing the gram capacity of the active material of the first positive electrode active material layer in the abutting area, it is possible to Decrease the active material capacity per unit area of the first positive electrode active material layer in the abutting area, so that the unit area capacity of the first positive active material layer in the abutting area is smaller than the unit area capacity of the second positive active material layer in the non-abutting area , which can effectively reduce the risk of lithium precipitation caused by the extrusion of the electrolyte when the abutting area and the shell are abutting.
  • the ratio of the weight of the active material of the first negative electrode active material layer to the weight of the first negative electrode active material layer is greater than the weight of the active material of the second negative electrode active material layer The ratio to the weight of the second negative electrode active material layer; and/or, the ratio of the weight of the active material of the first positive electrode active material layer to the weight of the first positive electrode active material layer is less than the second positive electrode The ratio of the weight of the active material of the active material layer to the weight of the second positive electrode active material layer.
  • the weight ratio of the active material in the first negative electrode active material layer in the abutting area is increased, thereby increasing the first negative electrode active material in the abutting area.
  • the active material capacity per unit area of the material layer and/or by reducing the active material in the first positive active material layer of the abutting region, reducing the weight ratio of the active material in the first positive active material layer of the abutting region, thereby reducing the resistance
  • the active material capacity per unit area of the first positive active material layer in the abutting area can effectively reduce the risk of lithium precipitation caused by the extrusion of the electrolyte when the abutting area is abutting against the shell.
  • the active material capacity per unit area of one of the two adjacent first negative active material layers is greater than the active material per unit area of the other first negative active material layer capacity, the other first negative electrode active material layer is closer to the thickness center plane than the one first negative electrode active material layer; and/or, one of the two adjacent first positive electrode active material layers
  • the active material capacity per unit area of the first positive electrode active material layer is smaller than the active material capacity per unit area of another first positive electrode active material layer, and the other first positive electrode active material layer is compared with the one first positive electrode active material layer. closer to the thickness center plane.
  • the active material capacity per unit area of the one whose thickness center plane is farther is greater than the unit area active material capacity of the other; and/or the shell of the two adjacent first positive electrode active material layers whose shell is closer to the thickness center plane and farther away.
  • the capacity of the active material per unit area is smaller than the capacity of the other active material per unit area, which can further effectively reduce the risk of lithium precipitation caused by the extrusion of the electrolyte when the abutting area and the shell are abutted.
  • the gram capacity of the active material of one of the two adjacent first negative electrode active material layers is greater than the gram capacity of the active material of the other first negative electrode active material layer capacity, the other first negative electrode active material layer is closer to the thickness center plane than the one first negative electrode active material layer; and/or, one of the two adjacent first positive electrode active material layers
  • the gram capacity of the active material of the first positive electrode active material layer is smaller than the gram capacity of the active material of the other first positive electrode active material layer, which is compared with the one first positive electrode active material layer. The layer is closer to the thickness center plane.
  • the capacity of the first negative electrode active material layer can be increased.
  • the active material capacity per unit area, so that the active material capacity per unit area of one of the two adjacent first negative electrode active material layers that is closer to the casing is greater than the unit area of the other first negative electrode active material layer.
  • Active material capacity; and/or, by reducing the gram capacity of the active material of one of the two adjacent first positive electrode active material layers that is closer to the casing, the first positive electrode activity can be reduced
  • the active material capacity per unit area of the material layer, so that the active material capacity per unit area of one of the two adjacent first positive active material layers that is closer to the shell is smaller than that of the other first positive active material layer
  • the active material capacity per unit area can further effectively reduce the risk of lithium precipitation caused by the extrusion of the electrolyte when the abutting area and the shell are abutting.
  • the ratio of the weight of the active material of one of the two adjacent first negative electrode active material layers to the weight of the one first negative electrode active material layer is greater than The ratio of the weight of the active material of the other first negative electrode active material layer to the weight of the other first negative electrode active material layer, the other first negative electrode active material layer compared to the one first negative electrode active material layer is closer to the thickness center plane; and/or, the weight of the active material of one of the two adjacent first positive electrode active material layers is the same as the weight of the one first positive electrode active material layer.
  • the ratio of the weight is less than the ratio of the weight of the active material of the other first positive electrode active material layer to the weight of the other first positive electrode active material layer, and the other first positive electrode active material layer is compared with the one first positive electrode active material layer.
  • a positive active material layer is closer to the thickness center plane.
  • the weight of the active material in the first negative electrode active material layer can be increased. ratio, thereby increasing the active material capacity per unit area of one of the two adjacent first negative electrode active material layers that is closer to the casing; and/or by reducing the adjacent two first negative electrode active material layers In the active material layer, the active material in a first positive electrode active material layer that is closer to the casing can reduce the weight ratio of the active material in the first positive electrode active material layer, thereby reducing the adjacent two first negative electrode active materials.
  • the active material capacity per unit area of a first positive electrode active material layer in the layer that is closer to the shell can effectively reduce the risk of lithium precipitation caused by the extrusion of the electrolyte in the more severely squeezed position in the abutment area.
  • the first negative electrode active material layer includes a plurality of negative electrode active segments, and each of the first positive electrode active material layers includes a plurality of positive electrode active segments; two adjacent negative electrode active segments The active material capacity per unit area of one negative active segment of the segments is greater than the active material capacity per unit area of another negative active segment, the one negative active segment being closer to the other negative active segment than the other negative active segment. the center of the first negative electrode active material layer; and/or, the active material capacity per unit area of one of the two adjacent positive electrode active segments is smaller than the active material capacity per unit area of the other positive electrode active segment, the One positive active segment is closer to the center of the first positive active material layer than the other positive active segment.
  • the active material capacity per unit area of one negative active segment in the center is greater than the active material capacity per unit area of the other negative active segment, and/or the two adjacent positive active segments are closer to the center of the first positive active material layer
  • the active material capacity per unit area of one positive active section is smaller than the active material capacity per unit area of the other positive active section, which can further effectively reduce the lithium precipitation caused by the extrusion of the electrolyte when the abutting area and the shell are abutted. risk.
  • the gram capacity of the active material in one of the two adjacent negative electrode active segments is greater than the gram capacity of the active material in the other negative electrode active segment, the one The negative electrode active segment is closer to the center of the first negative electrode active material layer than the other negative electrode active segment; and/or, the activity of one positive electrode active segment in two adjacent positive electrode active segments The gram capacity of the material is less than the gram capacity of the active material of another positive active segment, the one positive active segment being closer to the center of the first positive active material layer than the other positive active segment.
  • the capacity of the negative electrode active segment can be increased.
  • the active material capacity per unit area so that the active material capacity per unit area of one negative electrode active segment that is closer to the center of the first negative electrode active material layer is greater than the unit area of the other negative electrode active segment Active material capacity; and/or, by reducing the gram capacity of the active material of one of the two adjacent positive active segments that is closer to the center of the first positive active material layer, the positive active region can be reduced
  • the active material capacity per unit area of the segment so that the active material capacity per unit area of one of the two adjacent positive active segments, which is closer to the center of the first positive active material layer, is greater than that of the other positive active segment.
  • the capacity of the active material per unit area can effectively reduce the risk of lithium precipitation caused by the extrusion of the electrolyte when the abutting area and the shell abut.
  • a ratio of the weight of the active material of one of the two adjacent negative electrode active segments to the weight of the one negative electrode active segment is greater than the weight of the other negative electrode active segment a ratio of the weight of the active material to the weight of the other negative electrode active segment, the one negative electrode active segment being closer to the center of the first negative electrode active material layer than the other negative electrode active segment; and /or, the ratio of the weight of the active material of one positive active segment to the weight of the one positive active segment in the adjacent two positive active segments is smaller than the weight of the active material of the other positive active segment to the weight of the one positive active segment The ratio of the weight of another positive active segment, the one positive active segment is closer to the center of the first positive active material layer than the other positive active segment.
  • the weight of the active material in the negative active segment can be increased. ratio, thereby increasing the active material capacity per unit area of the negative electrode active segment; and/or by reducing the capacity of one positive electrode active segment that is closer to the center of the first positive electrode active material layer among the two adjacent positive electrode active segments
  • the active material can reduce the weight ratio of the active material in the positive active section, thereby reducing the active material capacity per unit area of the positive active section, and can effectively reduce the amount of electrolyte being squeezed out when the abutting area and the shell are abutted. Risk of lithium precipitation.
  • each negative active segment is in the shape of a strip, and the plurality of negative active segments are arranged along the direction of the winding axis; and/or, each positive active segment is in the shape of a strip shape, the plurality of positive active segments are arranged along the direction of the winding axis.
  • the negative electrode active section and/or the positive electrode active section is in strip shape, and the coating of the negative electrode active material layer is convenient.
  • the plurality of negative active segments includes a central negative active segment and at least one peripheral negative active segment, each peripheral negative active segment being annular and surrounding the central negative active segment , the central negative active segment and the at least one peripheral negative active segment are radially distributed from the center of the first negative active material layer; and/or, the plurality of positive active segments include a central positive active segment segment and at least one peripheral positive active segment, each peripheral positive active segment is annular and surrounds the central positive active segment, the central positive active segment and the at least one peripheral positive active segment The center of a positive electrode active material layer is radially distributed.
  • each negative electrode active segment is ringed in the center of the first negative electrode active material layer, then along any direction, the unit area of the negative electrode active segment near the center of the two adjacent negative electrode active segments is The capacity of the active material is greater than the capacity of the active material per unit area of the other negative active segment; and/or each positive active segment is distributed in the center of the first positive active material layer, then along any direction, two adjacent The capacity of active material per unit area of one positive active section near the center of the positive active sections is smaller than the capacity of active material per unit area of the other positive active section, which can further reduce the serious squeeze in the abutting area. There is a risk of lithium precipitation as the electrolyte is squeezed out.
  • the central negative active segment and/or the central positive active segment is elliptical.
  • the central negative active section and/or the central positive active section are elliptical, which can be closer to the expansion and deformation state of the first negative active material layer and the first positive active material layer when the abutting area is abutted against the casing. , which is beneficial to reduce the risk of lithium precipitation caused by the extrusion of the electrolyte when the abutting area and the shell are abutting.
  • an embodiment of the present application provides a battery cell, including: a case and the electrode assembly provided according to the embodiment of the first aspect, the electrode assembly is accommodated in the case, and the abutting area is used for contacting with The housing abuts, and the non-abutting area is used for not abutting against the housing.
  • the active material capacity per unit area of the first negative electrode active material layer in the abutting area of the electrode assembly is greater than the unit area active material capacity of the second negative electrode active material layer in the non-abutting area; and/or the The active material capacity per unit area of the first positive electrode active material layer in the abutting area is smaller than the active material capacity per unit area of the second positive electrode active material layer in the non-abutting area.
  • the battery cell includes two electrode assemblies, the two electrode assemblies are arranged side by side along the thickness direction, and the abutting regions of the two electrode assemblies face away from each other set up.
  • the two electrode assemblies are arranged side by side in the thickness direction, there will inevitably be two areas that may abut against the inside of the casing, and the abutting areas of the two electrode assemblies are set away from each other, and vice versa. If the two electrode assemblies are arranged close to each other, the abutment areas of the two electrode assemblies can abut against the casing, which can effectively reduce the occurrence of the abutment areas at both ends of the electrode assembly in the direction of the arrangement of the electrode assembly and the casing when the battery cell is operating. There is a risk of lithium precipitation as the electrolyte is squeezed out.
  • an embodiment of the present application provides a battery, including the battery cell provided by any embodiment of the second aspect.
  • the active material capacity per unit area of the first negative electrode active material layer in the abutting area of the electrode assembly is greater than the unit area active material capacity of the second negative electrode active material layer in the non-abutting area; and/or the The active material capacity per unit area of the first positive electrode active material layer in the abutting area is smaller than the active material capacity per unit area of the second positive active material layer in the non-abutting area, which can effectively reduce the battery operation, due to the abutting area of the electrode assembly and the unit area active material capacity.
  • the abutment of the casing causes the electrolyte to be squeezed out, causing the risk of lithium precipitation.
  • an embodiment of the present application provides an electrical device, including the battery cell provided in any embodiment of the second aspect.
  • an embodiment of the present application provides a method for manufacturing an electrode assembly, including: providing a positive electrode sheet and a negative electrode sheet; stacking the negative electrode sheet and the positive electrode sheet and winding them around a winding axis to form a winding structure, so that the electrode assembly includes abutting areas on both sides of its thickness center plane for abutting against the casing and a non-abutting area not abutting with the casing, the thickness center plane being perpendicular to the The thickness direction of the electrode assembly passes through the winding axis; wherein, the negative electrode sheet includes a plurality of first negative electrode active material layers located in the abutting region and arranged in layers along the thickness direction and a plurality of first negative electrode active material layers located in the non-abutting region a plurality of second negative electrode active material layers arranged in layers in the thickness direction; the positive electrode sheet includes a plurality of first positive active material layers arranged in the abutting region and arranged in layers in the thickness direction; a
  • an embodiment of the present application provides a manufacturing equipment for an electrode assembly, including: a provision device for providing a positive electrode sheet and a negative electrode sheet; an assembly device for stacking the positive electrode sheet and the negative electrode sheet and winding them around The winding axis is wound to form a winding structure, so that the electrode assembly includes abutting areas located on both sides of its thickness center plane for abutting against the casing and non-abutting areas not abutting against the casing , the thickness center plane is perpendicular to the thickness direction of the electrode assembly and passes through the winding axis; wherein, the negative electrode sheet includes a plurality of first negative electrodes located in the abutting area and stacked along the thickness direction An active material layer and a plurality of second negative electrode active material layers located in the non-abutting region and arranged in layers in the thickness direction; the positive electrode sheet includes a plurality of second negative electrode active material layers located in the abutting region and arranged in layers in the thickness direction.
  • the active material capacity per unit area of the first negative electrode active material layer is greater than the The active material capacity per unit area of the second anode active material layer; and/or the active material capacity per unit area of the first cathode active material layer is smaller than the active material capacity per unit area of the second cathode active material layer.
  • FIG. 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.
  • FIG. 2 is a schematic structural diagram of a battery provided by some embodiments of the present application.
  • FIG. 3 is an exploded view of a battery cell provided by some embodiments of the present application.
  • FIG. 4 is a schematic structural diagram of an assembled battery cell according to some embodiments of the present application.
  • Fig. 5 is a sectional view in the direction of P0-P0 in Fig. 4;
  • FIG. 6 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application.
  • Fig. 7 is a sectional view of Fig. 6 along P1-P1;
  • FIG. 8 is a schematic structural diagram of electrode assemblies provided by other embodiments of the present application.
  • the first negative electrode active material layer includes a plurality of negative electrode active segments
  • FIG. 10 is a schematic structural diagram of a first negative electrode active material layer provided by some embodiments of the present application.
  • FIG. 11 is a schematic structural diagram of a first negative electrode active material layer provided by further embodiments of the present application.
  • FIG. 12 is a schematic structural diagram of a first negative electrode active material layer provided by other embodiments of the present application.
  • FIG. 13 is a schematic structural diagram of a first negative electrode active material layer provided by further embodiments of the present application.
  • FIG. 14 is a schematic structural diagram of a first negative electrode active material layer according to further embodiments of the present application (the central negative electrode active section is oval);
  • FIG. 15 is a schematic structural diagram of an electrode assembly provided by further embodiments of the present application.
  • FIG. 16 is a schematic structural diagram of electrode assemblies provided by further embodiments of the present application.
  • FIG. 17 is a schematic structural diagram of electrode assemblies provided by other embodiments of the present application.
  • the first positive electrode active material layer includes a plurality of positive electrode active segments
  • FIG. 19 is a schematic structural diagram of a first positive electrode active material layer provided by some embodiments of the present application.
  • FIG. 20 is a schematic structural diagram of a first positive electrode active material layer provided by further embodiments of the present application.
  • FIG. 21 is a schematic structural diagram of a first positive electrode active material layer provided by other embodiments of the present application.
  • FIG. 22 is a schematic structural diagram of a first positive electrode active material layer provided by further embodiments of the present application.
  • FIG. 23 is a schematic structural diagram of the first positive electrode active material layer provided by further embodiments of the present application (the central positive electrode active section is oval);
  • FIG. 24 is a schematic structural diagram of electrode assemblies provided by further embodiments of the present application (the active material capacities per unit area of the first positive active material layers on the two surfaces of the positive electrode current collector are different);
  • 25 is a schematic structural diagram of electrode assemblies provided by other embodiments of the present application (both the first negative electrode active material layer and the first positive electrode active material layer are improved);
  • 26 is a flowchart of a method for manufacturing an electrode assembly provided by some embodiments of the present application.
  • FIG. 27 is a structural block diagram of a manufacturing apparatus of an electrode assembly provided by some embodiments of the present application.
  • plural refers to two or more (including two).
  • the battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., which are not limited in the embodiments of the present application.
  • the battery cell may be in the form of a cylinder, a flat body, a rectangular parallelepiped, or other shapes, which are not limited in the embodiments of the present application.
  • the battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square-shaped battery cells, and soft-pack battery cells, which are not limited in the embodiments of the present application.
  • the battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.
  • the batteries mentioned in this application may include battery modules or battery packs, and the like.
  • Batteries typically include a case for enclosing one or more battery cells. The box can prevent liquids or other foreign objects from affecting the charging or discharging of the battery cells.
  • the battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator.
  • the battery cell mainly relies on the movement of metal ions between the positive and negative plates to work.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer is coated on the surface of the positive electrode current collector, and the positive electrode current collector without the positive electrode active material layer protrudes from the positive electrode current collector that has been coated with the positive electrode active material layer. , the positive electrode current collector without the positive electrode active material layer is used as the positive electrode tab.
  • the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate, etc.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer is coated on the surface of the negative electrode current collector, and the negative electrode current collector without the negative electrode active material layer protrudes from the negative electrode current collector that has been coated with the negative electrode active material layer. , the negative electrode current collector without the negative electrode active material layer is used as the negative electrode tab.
  • the material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon.
  • the number of positive tabs is multiple and stacked together, and the number of negative tabs is multiple and stacked together.
  • the material of the separator can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), and the like.
  • the electrode assembly may be a wound structure or a laminated structure, and the embodiment of the present application is not limited thereto.
  • Lithium precipitation is one of the main factors affecting the electrical performance and safety performance of the battery. Once lithium precipitation occurs, it will not only reduce the electrical performance of the battery, but also easily form dendrites with the accumulation of lithium precipitation. The separator may be punctured, causing a short circuit in the battery, causing a safety hazard. There are many reasons for the precipitation of lithium.
  • the embodiments of the present application provide a technical solution, by making the active material capacity per unit area of the first negative electrode active material layer in the abutting region of the electrode assembly used for abutting against the casing be greater than that of the non-abutting non-abutting region.
  • the active material capacity per unit area of the second negative electrode active material layer in the abutting region, and/or making the active material capacity per unit area of the first positive active material layer in the abutting region smaller than the second positive active material layer in the non-abutting region The active material capacity per unit area can effectively reduce the risk of lithium precipitation caused by the extrusion of the electrolyte when the abutting area and the shell are abutting.
  • Electrical equipment can be vehicles, mobile phones, portable devices, notebook computers, ships, spacecraft, electric toys and power tools, and so on.
  • Vehicles can be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc.
  • spacecraft include airplanes, rockets, space shuttles, spacecraft, etc.
  • electric toys include fixed Electric toys that are portable or mobile, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.
  • electric tools include metal cutting power tools, grinding power tools, assembling power tools and railway power tools, such as, Electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators and electric planers, etc.
  • the embodiments of the present application do not impose special restrictions on the above-mentioned electrical equipment.
  • the electric device is a vehicle 1000 as an example for description.
  • FIG. 1 is a schematic structural diagram of a vehicle 1000 according to some embodiments of the present application.
  • the interior of the vehicle 1000 is provided with the battery 100 , and the battery 100 may be provided at the bottom or the head or the rear of the vehicle 1000 .
  • the battery 100 may be used for power supply of the vehicle 1000 , for example, the battery 100 may be used as an operating power source of the vehicle 1000 .
  • the vehicle 1000 may also include a controller 200 and a motor 300 for controlling the battery 100 to supply power to the motor 300 , eg, for starting, navigating, and running the vehicle 1000 for work power requirements.
  • the battery 100 can not only be used as the operating power source of the vehicle 1000 , but also can be used as the driving power source of the vehicle 1000 to provide driving power for the vehicle 1000 instead or partially instead of fuel or natural gas.
  • the battery 100 includes a case body 10 and a battery cell 20 , the battery cell 20 is accommodated in the case body 10 , the case body 10 provides an accommodation space for the battery cell 20 , and the case body 10 includes a first case body portion 11 and the second case portion 12 , the first case portion 11 and the second case portion 12 are configured to jointly define an accommodation space for accommodating the battery cells 20 .
  • the battery 100 there may be one battery cell 20 or a plurality of battery cells 20 . If there are a plurality of battery cells 20, the plurality of battery cells 20 may be connected in series or in parallel or in a mixed connection. A mixed connection means that the plurality of battery cells 20 are both connected in series and in parallel.
  • the plurality of battery cells 20 can be directly connected in series or in parallel or mixed together, and then the whole formed by the plurality of battery cells 20 is accommodated in the box 10; of course, the plurality of battery cells 20 can also be connected in series first.
  • a battery module is formed in parallel or in a mixed connection, and a plurality of battery modules are connected in series or in parallel or in a mixed connection to form a whole, and are accommodated in the box 10 .
  • the battery cells 20 may be cylindrical, flat, or other shapes, or the like.
  • the battery 100 may further include a bus component (not shown in the figure), and the plurality of battery cells 20 may be electrically connected through the bus component, so as to realize the series or parallel connection of the plurality of battery cells 20 . mixed.
  • FIG. 3 shows an exploded view of a battery cell 20 provided by some embodiments of the present application
  • FIG. 4 shows a schematic structural diagram of the assembled battery cell 20
  • the battery cell 20 includes a casing 21 , an end cap assembly 22 and an electrode assembly 23 .
  • the casing 21 has an opening, the electrode assembly 23 is accommodated in the casing, and the end cap assembly 22 is used to cover the opening.
  • the housing 21 may have various shapes, such as a cylinder, a flat shape, and the like.
  • the shape of the casing can be determined according to the specific shape of the electrode assembly 23, for example, the electrode assembly 23 is a flat structure, and the casing can be a rectangular parallelepiped structure.
  • the material of the casing may also be various, for example, copper, iron, aluminum, stainless steel, aluminum alloy, etc., which is not particularly limited in the embodiment of the present application.
  • the number of electrode assemblies 23 of the battery cells 20 is plural. 3 and 4 exemplarily show a battery cell 20 whose outer casing is a rectangular parallelepiped and two electrode assemblies 23 are flat. In FIG. 3 , the number of electrode assemblies 23 is two, and the two electrode assemblies 23 are arranged side by side along the thickness direction X of the electrode assemblies 23 .
  • the case 21 has two side walls 211 arranged opposite to each other along the thickness direction X of the electrode assembly 23 , one electrode assembly 23 of the two electrode assemblies 23 is disposed close to one side wall 211 , and the other electrode assembly 23 It is arranged close to the other side wall 211 .
  • the battery cell 20 further includes at least one cell, and along the thickness direction X, the at least one cell is located between the two electrode assemblies 23 .
  • the structure of the cell may be the same as the structure of the electrode assembly 23 provided in the embodiment of the present application, and may also refer to the design of the existing cell, which will not be repeated here.
  • the electrode assembly 23 includes a negative electrode sheet 231 , a positive electrode sheet 232 and a separator 233 .
  • the positive electrode sheet 232 , the negative electrode sheet 231 and the separator 233 are stacked and wound around the winding axis to form the wound electrode assembly 23 .
  • the negative electrode sheet 231 includes a negative electrode current collector 2311 , a first negative electrode active material layer 2312 coated on both surfaces of the negative electrode current collector 2311 , and a second negative electrode active material layer 2313 coated on both surfaces of the negative electrode current collector 2311 .
  • the number of the first negative electrode active material layers 2312 is plural, and the number of the second negative active material layers 2313 is plural.
  • the first negative electrode active material layers 2312 and the second negative electrode active material layers 2313 are alternately distributed.
  • the positive electrode sheet 232 includes a positive electrode current collector 2321 , a first positive electrode active material layer 2322 coated on both surfaces of the positive electrode current collector 2321 , and a second positive electrode active material layer 2323 coated on both surfaces of the positive electrode current collector 2321 .
  • the number of the first positive electrode active material layers 2322 is plural, and the number of the second positive active material layers 2323 is plural.
  • the first positive electrode active material layers 2322 and the second positive electrode active material layers 2323 are alternately distributed.
  • the separator 233 is used to separate the negative electrode sheet 231 and the positive electrode sheet 232 to prevent short circuit.
  • the separator 233 has a large number of penetrating micropores, which can ensure the free passage of electrolyte ions and has good permeability to lithium ions.
  • the material of the diaphragm 233 may be PP or PE or the like.
  • the electrode assembly 23 has a straight area A0 and two bending areas A1, and the two bending areas A1 are respectively connected to two ends of the straight area A0.
  • the first negative electrode active material layer 2312, the first positive electrode active material layer 2322, the second negative electrode active material layer 2313, and the second positive electrode active material layer 2323 are all located in the flat region A0, and are stacked along the thickness direction X in the flat region A0 layout.
  • the electrode assembly 23 includes abutting regions B1 located on both sides of its thickness center plane B for abutting against the case 21 (shown in FIG. 5 ) and non-abutting regions B1 not abutting against the case 21 (shown in FIG. 5 ).
  • All the first negative electrode active material layers 2312 and all the first positive electrode active material layers 2322 are located in the abutment region B1 and are stacked in the thickness direction X, all the second negative electrode active material layers 2313 and all the second positive electrode active material layers 2323 is located in the non-abutting region B2 and is arranged in layers along the thickness direction X.
  • the two parts of the straight area A0 located on both sides of the thickness center plane B of the electrode assembly 23 are located in the abutment area B1 and the non-abutment area B2, respectively.
  • the active material capacity per unit area of the first negative electrode active material layer 2312 on the two surfaces of any layer of negative electrode current collector 2311 is the same, then the active material capacity per unit area of the first negative electrode active material layer 2312 is the same.
  • the material capacity may represent the active material capacity per unit area of the first negative electrode active material layer 2312 on both surfaces of the negative electrode current collector 2311 of the corresponding layer. If the active material capacity per unit area of the second negative electrode active material layer 2313 on the two surfaces of any layer of negative electrode current collector 2311 is the same, the active material capacity per unit area of the second negative electrode active material layer 2313 can represent the negative electrode current collector 2311 of the corresponding layer. Active material capacity per unit area of the second negative electrode active material layer 2313 on both surfaces.
  • the active material capacity per unit area of the first negative electrode active material layer 2312 is greater than the unit area active material capacity of the second negative electrode active material layer 2313 .
  • the active material capacity per unit area of the second negative electrode active material layer 2313 in the non-abutting region B2 that does not abut against the casing 21 meets the design requirements, that is, the unit area of the second negative electrode active material layer 2313 in the non-abutting region B2
  • the capacity of the active material reaches the first preset value
  • the second negative electrode active material layer 2313 in the non-abutting region B2 is less prone to lithium deposition.
  • the active material capacity per unit area of the first negative electrode active material layer 2312 located in the abutment region B1 is greater than the active material capacity per unit area of the second negative electrode active material layer 2313 located in the non-abutting region B2, that is, the first negative electrode active material layer 2312
  • the active material capacity per unit area is greater than the first preset value, it is equivalent to increasing the active material capacity per unit area of the first negative electrode active material layer 2312, and the first negative electrode active material layer 2312 can receive
  • the lithium ions released by 2322 are less likely to precipitate lithium in the first negative active material layer 2312 of the abutment area B1, which can effectively reduce the extrusion of the electrolyte when the abutment area B1 and the shell 21 are abutted. risk of lithium precipitation.
  • the active material capacity per unit area of the first negative electrode active material layer 2312 refers to the ratio of the active material capacity of the first negative electrode active material layer 2312 to the total area of the first negative electrode active material layer 2312
  • the second negative electrode active material refers to the ratio of the active material capacity of the second negative electrode active material layer 2313 to the total area of the second negative electrode active material layer 2313 .
  • the active material capacity of the first negative electrode active material layer 2312 is Q1
  • the area of the first negative electrode active material layer 2312 is S1
  • the capacity of the first negative electrode active material layer 2312 can be realized in many ways.
  • the capacity per unit area is larger than the capacity per unit area of the active material of the second negative electrode active material layer 2313 .
  • the gram capacity of the active material of the first negative electrode active material layer 2312 is greater than the gram capacity of the active material of the second negative electrode active material layer 2313 .
  • the active material capacity per unit area of the first negative electrode active material layer 2312 in the abutment region B1 can be increased, so that the first negative electrode active material layer 2312 in the abutment region B1
  • the capacity per unit area of the first negative electrode active material layer 2312 is greater than the capacity per unit area of the second negative electrode active material layer 2313 in the non-abutting region B2, which can effectively reduce the amount of electrolyte that is squeezed out when the abutting region B1 and the casing 21 abut against. Risk of lithium precipitation.
  • the gram capacity refers to the ratio of the electric capacity that can be released by the active material inside the battery 100 to the mass of the active material.
  • the gram capacity is related to the active material in the first negative electrode active material layer 2312 and the active material in the second negative electrode active material layer 2313, for example, the active material of the first negative electrode active material layer 2312 is a silicon compound, and the second negative electrode active material The active material of layer 2313 is graphite.
  • the material activity of the silicon compound is greater than the material activity of graphite, so that the lithium intercalation ability of the first negative electrode active material layer 2312 is greater than the lithium intercalation ability of the second negative electrode active material layer 2313, which can reduce the abutting area B1 being squeezed by the electrolyte. Impact.
  • the ratio of the weight of the active material of the first negative electrode active material layer 2312 to the weight of the first negative electrode active material layer 2312 is greater than the weight of the active material of the second negative electrode active material layer 2313 to the weight of the second negative electrode active material
  • the ratio of the weights of the layers 2313 is such that the active material capacity per unit area of the first negative electrode active material layer 2312 is greater than the active material capacity per unit area of the second negative electrode active material layer 2313 .
  • Both the first negative electrode active material layer 2312 and the second negative electrode active material layer 2313 include active materials, binders and conductive agents. By increasing the active material in the first negative electrode active material layer 2312, the first negative electrode active material layer 2312 is improved The proportion of active materials in the first negative electrode active material layer 2312 is increased, so that the unit area active material capacity of the first negative electrode active material layer 2312 is greater than the unit area of the second negative electrode active material layer 2313. Area active material capacity.
  • the weight of the binder and the conductive agent in the first negative electrode active material layer 2312 may also be reduced, so as to reduce the weight of the first negative electrode active material layer 2312, thereby improving the activity of the active material in the first negative electrode.
  • the proportion in the material layer 2312 is equivalent to reducing the coating weight of the first negative electrode active material layer 2312, and it can not only make the weight of the active material in the first negative electrode active material layer 2312 equal to the weight of the first negative electrode active material layer 2312.
  • the ratio of the weight is greater than the ratio of the weight of the active material of the second negative electrode active material layer 2313 to the weight of the second negative electrode active material layer 2313, which can also reduce the demand of the first negative electrode active material layer 2312 for the electrolyte, through a smaller amount of electrolysis
  • the first negative electrode active material layer 2312 can be infiltrated by the liquid, which can reduce the influence of the first negative electrode active material layer 2312 by the extrusion of the electrolyte.
  • the active material capacity per unit area of one of the two adjacent first negative electrode active material layers 2312 is greater than that of the other one.
  • the active material capacity per unit area of one first negative electrode active material layer 2312, the other first negative electrode active material layer 2312 is closer to the thickness center plane B than the one first negative electrode active material layer 2312.
  • the capacity per unit area of one of the two adjacent first negative electrode active material layers 2312 that is closer to the side wall 211 of the casing 21 can be greater than that of the other second negative electrode active material layer 2312 in many ways.
  • the active material capacity per unit area of the negative electrode active material layer 2313 can be greater than that of the other second negative electrode active material layer 2312 in many ways.
  • the gram capacity of the active material of one of the two adjacent first negative electrode active material layers 2312 is greater than the gram capacity of the active material of the other first negative electrode active material layer 2312 , the other first negative electrode active material layer 2312 is closer to the thickness center plane B than the one first negative electrode active material layer 2312 . Understandably, in the abutment region B1, in the thickness direction X, the farther from the thickness center plane B (closer to the sidewall 211 of the casing 21), the greater the gram capacity of the first negative active material layer 2312.
  • the gram capacity is related to the active material in the first negative electrode active material layer 2312, such as the activity of the first negative electrode active material layer 2312 that is closer to the side wall 211 of the casing 21 among the two adjacent first negative electrode active material layers 2312.
  • the material is a silicon compound, and the active material of the other first negative active material is graphite, and the material activity of the silicon compound is greater than that of the graphite, so that the two adjacent first negative active material layers 2312 are closer to the shell.
  • the lithium intercalation capability of one first negative electrode active material layer 2312 of the sidewall 211 of 21 is greater than that of the other first negative electrode active material layer 2312, which can further reduce the influence of the abutment region B1 by the extrusion of the electrolyte.
  • the ratio of the weight of the active material of one of the two adjacent first negative electrode active material layers 2312 to the weight of the one first negative electrode active material layer 2312 is greater than The ratio of the weight of the active material of the other first negative electrode active material layer 2312 to the weight of the other first negative electrode active material layer 2312, the other first negative electrode active material layer 2312 compared to the One of the first anode active material layers 2312 is closer to the thickness center plane B. As shown in FIG. It can be understood that in the abutment region B1, in the thickness direction X, the farther from the thickness center plane B (the closer to the side wall 211 of the casing 21), the weight of the active material of the first negative electrode active material layer 2312 is the same as that of the first negative electrode. The ratio of the weight of the active material layer 2312 is larger.
  • the first negative active material is increased.
  • the proportion of the active material in the layer 2312, thereby increasing the active material capacity per unit area of the first negative electrode active material layer 2312, so that the unit area active material capacity of the first negative electrode active material layer 2312 close to the casing 21 is greater than the other The active material capacity per unit area of one first negative electrode active material layer 2312 .
  • the weight of the binder and the conductive agent in the first negative electrode active material layer 2312 closer to the case 21 may also be reduced, so that the first negative electrode active material layer 2312 closer to the case 21 is The weight is reduced, thereby increasing the proportion of active materials in the first negative electrode active material layer 2312, which is equivalent to reducing a first negative electrode active material that is closer to the casing 21 in the two adjacent first negative electrode active material layers 2312
  • the coating weight of the layer 2312 can not only make the ratio of the weight of the active material in the first negative electrode active material layer 2312 to the weight of the first negative electrode active material layer 2312 greater than that of the active material in the second negative electrode active material layer 2313
  • the ratio of the weight of the second negative electrode active material layer 2313 to the weight of the other second negative electrode active material layer 2313 can also reduce the demand for the electrolyte of the first negative electrode active material layer 2312 close to the casing 21, and the first negative electrode can be realized by a smaller amount of electrolyte.
  • the first negative electrode active material layer 2312 includes a plurality of negative electrode active segments, and the unit area activity of one negative electrode active segment in two adjacent negative electrode active segments is The material capacity is greater than the active material capacity per unit area of another negative electrode active segment, and the one negative electrode active segment is closer to the center O1 of the first negative electrode active material layer than the other negative electrode active segment. It can be understood that, in the abutment region B1, the active material capacity per unit area of the negative electrode active segment that is closer to the center O1 of the first negative electrode active material layer is greater.
  • the active material capacity per unit area of the negative electrode active segment closer to the center O1 of the first negative electrode active material layer is larger, so that the active material near the first negative electrode active material layer has a larger capacity per unit area.
  • the position of the center O1 of the material layer is less affected by the extrusion of the electrolyte, which can further effectively reduce the risk of lithium precipitation caused by extrusion of the electrolyte when the abutment area B1 abuts against the shell 21 .
  • the gram capacity of the active material in one of the two adjacent negative active segments is greater than the gram capacity of the active material in the other negative active segment, the one negative active segment It is closer to the center O1 of the first negative electrode active material layer than the other negative electrode active material layer, so that the active material capacity per unit area closer to the first negative electrode active material layer 2312 is larger than that of the other first negative electrode active material layer Active material capacity per unit area of layer 2312.
  • the ratio of the weight of the active material of one of the two adjacent negative active segments to the weight of the one negative active segment is greater than the weight of the active material of the other negative active segment
  • the ratio to the weight of the other negative electrode active segment, the one negative electrode active segment is closer to the center O1 of the first negative electrode active material layer than the other negative electrode active segment.
  • the proportion of the active material in the negative active segment is increased, thereby increasing the negative electrode active segment.
  • the active material capacity per unit area of the negative active section so that the active material capacity per unit area of the negative active section that is closer to the center O1 of the first negative active material layer in two adjacent negative active sections is greater than that of the other negative active area The active material capacity per unit area of the segment.
  • the weight of the binder and the conductive agent of the negative electrode active segment near the center of the first negative electrode active material layer 2312 can also be reduced, so as to reduce the weight of the negative electrode active segment, thereby improving the The proportion of the first negative electrode active material layer 2312 is equivalent to reducing the coating weight of one negative electrode active segment near the center of two adjacent negative electrode active segments, which not only enables the The ratio of the weight of the active material to the weight of the negative electrode active segment is greater than the ratio of the weight of the active material of the other negative electrode active segment to the weight of the other negative electrode active segment, and it can also reduce the proximity of the first negative electrode active material.
  • the negative electrode active segment in the center O1 of the layer requires electrolyte solution, and the negative electrode active segment can be infiltrated by a smaller amount of electrolyte solution, which can reduce the influence of the first negative electrode active material layer 2312 by electrolyte extrusion.
  • the negative electrode active segments may have various shapes, and the shapes of each negative electrode active segment may be the same or different.
  • each negative electrode active segment is in the shape of a strip, and each negative electrode active segment is arranged along the direction of the winding axis. The number of negative active segments is odd.
  • the number of anode active segments is seven.
  • the first negative electrode active segment 2312a the second negative electrode active segment 2312b, the third negative electrode active segment 2312c, the fourth negative electrode active segment 2312d, the fifth negative electrode active segment 2312e, and the sixth negative electrode active segment 2312e.
  • the center plane of the fourth negative electrode active segment 2312d coincides with the center surface O2 of the first negative electrode active material layer and passes through the center O1 of the first negative electrode active material layer, the first negative electrode active segment 2312a and The seventh anode active segment 2312g is symmetrical about the center plane O2 of the first anode active material layer, the second anode active segment 2312b and the sixth anode active segment 2312f are symmetrical about the center plane O2 of the first anode active material layer, and the third The negative electrode active segment 2312c and the fifth negative electrode active segment 2312e are symmetrical with respect to the center plane O2 of the first negative electrode active material layer.
  • the active material capacity per unit area of the fourth negative electrode active segment 2312d is greater than the unit area active material capacity of the third negative electrode active segment 2312c, and the unit area active material capacity of the third negative electrode active segment 2312c is greater than the second negative electrode active segment
  • the active material capacity per unit area of 2312b, the active material capacity per unit area of the second negative electrode active segment 2312b is greater than the active material capacity per unit area of the first negative electrode active segment 2312a
  • the active material capacity per unit area of the fourth negative electrode active segment 2312d is greater than
  • the active material capacity per unit area of the fifth anode active segment 2312e, the active material capacity per unit area of the fifth anode active segment 2312e is greater than the active material capacity per unit area of the sixth anode active segment 2312f, and the capacity per unit area of the sixth anode active segment 2312f
  • the active material capacity per unit area is greater than the active material capacity per unit area of the seventh negative electrode active segment 2312 g.
  • the number of negative active segments is three, and along the winding axis direction Z are the first negative active segment 2312 a , the second negative active segment 2312 b and the third negative active segment in sequence. Section 2312c.
  • the center plane of the second negative electrode active segment 2312b overlaps with the center surface O2 of the first negative electrode active material layer and passes through the center O1 of the first negative electrode active material layer, the first negative electrode active segment 2312a and The third anode active segment 2312c is symmetrical with respect to the center plane O2 of the first anode active material layer.
  • the active material capacity per unit area of the second negative electrode active segment 2312b is greater than that of the first negative electrode active segment 2312a, and the active material capacity per unit area of the second negative electrode active segment 2312b is greater than that of the third negative electrode active segment 2312c Active material capacity per unit area.
  • the active material capacity per unit area of the first negative electrode active segment 2312a is the same as the unit area active material capacity of the third negative electrode active segment 2312c.
  • Symmetric means that the area and the active material capacity per unit area of two negative electrode active segments that are symmetrical with respect to the center plane O2 of the first negative electrode active material layer are the same.
  • the distance between each negative electrode active segment relative to the center O1 of the first negative electrode active material layer can be understood as being relative to the center plane of the first negative electrode active material layer. O2 distance.
  • the plurality of negative active segments includes a central negative active segment 2312h and at least one peripheral negative active segment, each peripheral negative active segment is annular and surrounds The central anode active section 2312h, the central anode active section 2312h and the at least one peripheral anode active section are radially distributed at the center O1 of the first anode active material layer.
  • Each negative active segment is surrounded by the center O1 of the first negative active material layer, then along any direction, the active material capacity per unit area of the negative active segment close to the center of the two adjacent negative active segments is equal to The capacity of the active material per unit area is larger than that of the other anode active segment.
  • the active material capacity per unit area of the central negative active segment 2312h is greater than the active material capacity per unit area of the peripheral negative active segment.
  • the central negative active segment 2312h is rectangular, the number of peripheral negative active segments is one, defined as the first peripheral negative active segment 2312i, the inner contour of the peripheral negative active segment It is rectangular and coincides with the outer contour of the central anode active section 2312h, and the outer contour of the peripheral anode active section is rectangular.
  • the center of the central anode active section 2312h is the center O1 of the first anode active material layer.
  • the number of peripheral negative active segments is three, which are the first peripheral negative active segment 2312i , the second peripheral negative active segment 2312j and the third peripheral negative active segment, respectively 2312k.
  • the first peripheral negative active section 2312i is ringed around the central negative active section 2312h
  • the inner contour of the first peripheral negative active section 2312i coincides with the outer contour of the central negative active section 2312h
  • the second peripheral negative active section 2312j is ringed Distributed in the first peripheral anode active section 2312i
  • the inner contour of the second peripheral anode active section 2312j coincides with the outer contour of the first peripheral anode active section 2312i
  • the third peripheral anode active section 2312k is distributed around the second peripheral
  • the inner contour of the negative active section 2312j and the third peripheral negative active section 2312k coincide with the outer contour of the second peripheral negative active section 2312j
  • the outer contour of the third peripheral negative active section 2312k is rectangular.
  • the center of the central anode active section 2312h is the center O1 of the first anode active material layer.
  • the outer contour of the central anode active section 2312h is rectangular, the inner and outer contours of the first peripheral anode active section 2312i are both rectangular, the inner and outer contours of the second peripheral anode active section 2312j are both rectangular, and the third peripheral anode active section 2312j has a rectangular outer contour. Both the inner and outer contours of the peripheral anode active section 2312k are rectangular.
  • the outer contour of the central anode active segment 2312h is elliptical.
  • the inner and outer contours of the first peripheral anode active section 2312i are both elliptical; the inner and outer contours of the second peripheral anode active section 2312j are both elliptical; the inner contour of the third peripheral anode active section 2312k is elliptical, and the outer contour of the third peripheral negative electrode active material layer is rectangular.
  • the central anode active section 2312h is elliptical, which can be closer to the expansion and deformation state of the first anode active material layer 2312 when the abutment area B1 abuts against the casing 21, which is beneficial to reduce the abutment of the abutment area B1 and the casing 21.
  • the electrolyte is squeezed out, there is a risk of lithium precipitation.
  • the particle size of the active material of the first anode active material layer 2312 is smaller than the particle size of the active material of the second anode active material layer 2313 .
  • lithium ions are more easily diffused in the first negative electrode active material layer 2312, more uniformly distributed in the first negative electrode active material layer 2312, and less likely to accumulate in the first negative electrode active material layer 2312, thereby reducing the The risk of lithium precipitation can be reduced, and the fast charging performance of the first negative electrode active material layer 2312 can also be improved.
  • the particle size of the active material in the negative electrode active section that is closer to the center O1 of the first negative electrode active material layer in each of the first negative electrode active material layers 2312 is smaller.
  • the third peripheral anode active section 2312k is the region with the largest particle size of the active material in the first anode active material layer 2312 , and the third peripheral anode active section 2312k
  • the particle size of the active material in the second peripheral anode active segment 2312j is D
  • the particle sizes of the active material in the second peripheral anode active segment 2312j were 0.8D, 0.6D and 0.4D, respectively.
  • the central anode active section 2312h expands the most, and the particle size of the active material in the central anode active section 2312h is the smallest, which can effectively improve the diffusion capacity of lithium ions in the central anode active section 2312h, and is not easy to
  • the central anode active segment 2312h aggregates, reducing the risk of lithium precipitation.
  • the active material capacities per unit area of the first negative active material layers 2312 on both surfaces of the negative electrode current collector 2311 are different.
  • the active material capacity per unit area of the first negative electrode active material layer 2312 on the surface of the negative electrode current collector 2311 on the side closer to the thickness center plane B is smaller than that on the surface of the negative electrode current collector 2311 on the side farther from the thickness center plane B.
  • the active material capacity per unit area of the first negative electrode active material layer 2312 is different.
  • the active material capacity per unit area of the inner negative electrode active material layer 2312m inside the negative electrode current collector 2311 is smaller than the active material capacity per unit area of the outer negative electrode active material layer 2312n.
  • the inner side and outer side of the negative electrode current collector 2311 are relative to the thickness center plane B, the side closer to the thickness center plane B is the inner side, and the side farther from the thickness center plane B is the outer side.
  • the positive electrode sheet 232 can also be improved to reduce the risk of lithium precipitation due to the extrusion of the electrolyte when the abutting region B1 abuts against the casing 21 .
  • the active material capacity per unit area of the first positive active material layer 2322 is smaller than the active material capacity per unit area of the second positive active material layer 2323 .
  • the active material capacity per unit area of the second positive active material layer 2323 on the two surfaces of any one layer of positive current collector 2321 is the same, then the active material per unit area of the second positive active material layer 2323
  • the material capacity may represent the active material capacity per unit area of the second positive electrode active material layer 2323 on both surfaces of the negative electrode current collector 2311 of the corresponding layer.
  • the active material capacity per unit area of the second positive electrode active material layer 2323 in the non-abutting region B2 that does not abut against the casing 21 meets the design requirements, that is, the unit area of the second positive electrode active material layer 2323 in the non-abutting region B2
  • the capacity of the active material reaches the second preset value
  • the second negative electrode active material layer 2313 in the non-abutting region B2 is less prone to lithium deposition.
  • the active material capacity per unit area of the first positive active material layer 2322 located in the abutting region B1 is less than the active material capacity per unit area of the second positive active material layer 2323 located in the non-abutting region B2, that is, the first positive active material layer 2322
  • the active material capacity per unit area is less than the second preset value, which is equivalent to reducing the active material capacity per unit area of the first positive electrode active material layer 2322, so the first negative electrode active material layer 2312 can accept the release from the first positive electrode active material layer 2322.
  • the lithium ions of the first negative electrode in the abutment area B1 are less likely to be precipitated, thereby effectively reducing the risk of lithium precipitation caused by the electrolyte being squeezed out when the abutment area B1 is abutted against the casing 21 .
  • the active material capacity per unit area of the first positive electrode active material layer 2322 refers to the ratio of the active material capacity of the first positive electrode active material layer 2322 to the total area of the first positive electrode active material layer 2322
  • the second positive electrode active material refers to the ratio of the active material capacity of the second positive electrode active material layer 2323 to the total area of the second positive electrode active material layer 2323 .
  • the active material capacity of the first positive electrode active material layer 2322 is E1
  • the area of the first positive electrode active material layer 2322 is G1
  • the capacity of the first positive electrode active material layer 2322 can be realized in many ways.
  • the capacity per unit area is smaller than the capacity per unit area of the active material of the second positive electrode active material layer 2323 .
  • the gram capacity of the active material of the first positive electrode active material layer 2322 is less than the gram capacity of the active material of the second positive electrode active material layer 2323 .
  • the active material capacity per unit area of the first positive electrode active material layer 2322 in the abutment region B1 can be reduced, so that the abutment region B1
  • the unit area capacity of the first positive electrode active material layer 2322 is smaller than the unit area capacity of the second positive electrode active material in the non-abutting area B2, which can effectively reduce the amount of electrolyte that is squeezed out when the abutting area B1 and the casing 21 abut. Risk of lithium precipitation.
  • the gram capacity is related to the active material in the first positive active material layer 2322 and the active material in the second positive active material layer 2323, for example, the active material of the first positive active material layer 2322 and the active material of the second positive active material layer 2323.
  • the materials are different.
  • the active material of the first positive electrode active material layer 2322 is lithium iron phosphate
  • the active material of the second positive electrode active material layer 2323 is ternary lithium.
  • the material activity of lithium iron phosphate is less than the material activity of ternary lithium, so that the delithiation capability of the first positive electrode active material layer 2322 is smaller than that of the second positive electrode active material layer 2323, which can further reduce the electrolysis of the contact area B1.
  • the effect of liquid extrusion is related to the active material in the first positive active material layer 2322 and the active material in the second positive active material layer 2323, for example, the active material of the first positive active material layer 2322 and the active material of the second positive active material layer 2323.
  • the materials are different.
  • the ratio of the weight of the active material of the first cathode active material layer 2322 to the weight of the first cathode active material layer 2322 is less than the weight of the active material of the second cathode active material layer 2323 to the weight of the second cathode active material layer 2323 weight ratio.
  • Both the first positive active material layer 2322 and the second positive active material layer 2323 include active materials, binders and conductive agents. By reducing the active material in the first positive active material layer 2322, the first positive active material layer 2322 is reduced. The ratio of the active material in the first positive electrode active material layer 2322 is reduced, so that the active material capacity per unit area of the first positive electrode active material layer 2322 is smaller than that of the second positive electrode active material layer 2323. Active substance capacity.
  • the active material capacity per unit area of one of the two adjacent first positive electrode active material layers 2322 is smaller than that of the other one.
  • the active material capacity per unit area of one first positive active material layer 2322, the other first positive active material layer 2322 is closer to the thickness center plane B than the one first positive active material layer 2322. It can be understood that, in the abutment region B1, along the thickness direction X, the farther from the thickness center plane B (the closer to the side wall 211 of the casing 21), the smaller the active material capacity per unit area of the first positive active material layer 2322 is. , which can further effectively reduce the risk of lithium precipitation caused by the extrusion of the electrolyte when the abutting region B1 and the casing 21 abut.
  • the unit area capacity of one of the two adjacent first positive electrode active material layers 2322 that is closer to the casing 21 can be smaller than that of the other second positive electrode active material layer 2323 in many ways. Area active material capacity.
  • the gram capacity of the active material of the first positive active material layer 2322 of one of the adjacent two first positive active material layers 2322 is less than the gram capacity of the active material of the other first positive active material layer 2322 capacity, the other first positive electrode active material layer 2322 is closer to the thickness center plane B than the one first positive electrode active material layer 2322 . Understandably, in the abutment region B1, in the thickness direction X, the farther from the thickness center plane B (the closer to the side wall 211 of the casing 21), the smaller the gram capacity of the first positive active material layer 2322.
  • the gram capacity is related to the active material in the first positive electrode active material layer 2322.
  • the active materials of the two adjacent first positive electrode active material layers 2322 are different, and the active material of the first positive electrode active material layer 2322 close to the casing 21 is different.
  • It is lithium iron phosphate
  • the active material of the other first positive active material is ternary lithium, so that the first positive active material layer 2322 of the two adjacent first positive active material layers 2322 close to the casing 21 is removed.
  • the lithium capability is smaller than the delithiation capability of the other first positive active material layer 2322, which can further reduce the influence of the abutting region B1 by the extrusion of the electrolyte.
  • the ratio of the weight of the active material of one of the two adjacent first positive electrode active material layers 2322 to the weight of the one first positive electrode active material layer 2322 is less than The ratio of the weight of the active material of the other first positive electrode active material layer 2322 to the weight of the other first positive electrode active material layer 2322, the other first positive electrode active material layer 2322 One of the first positive electrode active material layers 2322 is closer to the thickness center plane B. As shown in FIG. Understandably, in the abutment region B1, in the thickness direction X, the farther from the thickness center plane B (the closer to the side wall 211 of the casing 21) is the weight of the active material of the first positive electrode active material layer 2322 is the same as that of the first positive electrode. The ratio of the weight of the active material layer 2322 is smaller.
  • the proportion of the active material in the first positive active material layer 2322 is reduced, so that The active material capacity per unit area of the first positive electrode active material layer 2322 is reduced, so that the unit area active material capacity of the first positive electrode active material layer 2322 close to the casing 21 is smaller than that of the other first positive electrode active material layer 2322 Active substance capacity.
  • the first positive electrode active material layer 2322 includes a plurality of positive electrode active segments, and the unit area activity of one positive electrode active segment in two adjacent positive electrode active segments is The material capacity is smaller than the active material capacity per unit area of another positive electrode active segment, and the one positive electrode active segment is closer to the center O3 of the first positive electrode active material layer than the other positive electrode active segment. It can be understood that, in the abutment region B1, the active material capacity per unit area of the positive electrode active segment that is closer to the center O3 of the first positive electrode active material layer is smaller.
  • the active material capacity per unit area of the negative electrode active segment closer to the center O3 of the first positive electrode active material layer is smaller, thereby reducing the capacity of the negative electrode active segment near the first positive electrode
  • the delithiation ability of the positive electrode active section at the center of the active material layer 2322 makes the position close to the center of the first negative electrode active material layer 2312 less affected by the extrusion of the electrolyte, which can further effectively reduce the impact of the contact area B1 and the When the casing 21 abuts against, the electrolyte is squeezed out, causing the risk of lithium precipitation.
  • the gram capacity of the active material of one of the two adjacent positive active segments is less than the gram capacity of the active material of the other positive active segment, the one positive active segment Compared with the other positive electrode active segment, it is closer to the center O3 of the first positive electrode active material layer, so that the active material capacity per unit area of the positive electrode active segment closer to the center O3 of the first positive electrode active material layer is smaller.
  • the ratio of the weight of the active material of one of the two adjacent positive active segments to the weight of the one positive active segment is smaller than the weight of the active material of the other positive active segment.
  • the ratio of the weight to the weight of the other positive active segment, the one positive active segment is closer to the center O3 of the first positive active material layer than the other positive active segment, In order to make the active material capacity per unit area of the positive active segment closer to the center O3 of the first positive active material layer smaller.
  • the proportion of the active material in the positive active segment is reduced, thereby reducing the The active material capacity per unit area of the positive active section, so that the active material capacity per unit area of the positive active section closer to the center O3 of the first positive active material layer in the two adjacent positive active sections is smaller than that of the other positive active section The active material capacity per unit area of the segment.
  • the positive active segment may have various shapes, and the shapes of each negative active segment may be the same or different.
  • each positive active segment is in the shape of a strip, and each positive active segment is arranged along the direction of the winding axis.
  • the positive active section is strip-shaped, and the negative active material layer is easily coated. The number of negative active segments is odd.
  • the number of positive active segments is seven.
  • the first positive active segment 2322a the second positive active segment 2322b, the third positive active segment 2322c, the fourth positive active segment 2322d, the fifth positive active segment 2322e, and the sixth positive active segment 2322e.
  • the center plane of the fourth positive electrode active segment 2322d overlaps with the center surface O4 of the first positive electrode active material layer and passes through the center O3 of the first positive electrode active material layer, the first positive electrode active segment 2322a and The seventh positive active segment 2322g is symmetrical with respect to the central plane O4 of the first positive active material layer, the second positive active segment 2322b and the sixth positive active segment 2322f are symmetrical with respect to the central plane O4 of the first positive active material layer, and the third The positive electrode active segment 2322c and the fifth positive electrode active segment 2322e are symmetrical with respect to the center plane O4 of the first positive electrode active material layer.
  • the active material capacity per unit area of the fourth positive electrode active segment 2322d is smaller than that of the third positive electrode active segment 2322c, and the active material capacity per unit area of the third positive electrode active segment 2322c is smaller than that of the second negative electrode active segment 2312b.
  • the active material capacity per unit area, the active material capacity per unit area of the second positive active segment 2322b is smaller than the active material capacity per unit area of the first positive active segment 2322a; the active material capacity per unit area of the fourth positive active segment 2322d is smaller than the fifth active material capacity per unit area
  • the active material capacity per unit area of the positive electrode active segment 2322e, the active material capacity per unit area of the fifth positive electrode active segment 2322e is smaller than the active material capacity per unit area of the sixth positive electrode active segment 2322f, and the unit area of the sixth positive electrode active segment 2322f
  • the active material capacity is smaller than the active material capacity per unit area of the seventh positive electrode active segment 2322 g.
  • the number of positive active segments is three, and along the winding axis direction Z are the first positive active segment 2322a, the second positive active segment 2322b, and the third positive active segment in sequence. Section 2322c.
  • the center plane of the second positive electrode active segment 2322b coincides with the center surface O4 of the first positive electrode active material layer and passes through the center O3 of the first positive electrode active material layer, the first positive electrode active segment 2322a and The third positive electrode active segment 2322c is symmetrical with respect to the center plane O4 of the first positive electrode active material layer.
  • the active material capacity per unit area of the second positive active segment 2322b is smaller than that of the first positive active segment 2322a, and the active material capacity per unit area of the second positive active segment 2322b is smaller than that of the third positive active segment 2322c Active material capacity per unit area.
  • the active material capacity per unit area of the first positive electrode active segment 2322a is the same as that of the third positive electrode active segment 2322c.
  • the distance between each positive electrode active segment relative to the center O3 of the first positive electrode active material layer can be understood as being relative to the center plane of the first positive electrode active material layer O4's distance.
  • the plurality of positive active segments includes a central positive active segment 2322h and at least one peripheral positive active segment, each peripheral positive active segment is annular and surrounds The central positive active section 2322h, the central positive active section 2322h and the at least one peripheral positive active section are radially distributed at the center O3 of the first positive active material layer.
  • the active material capacity per unit area of the central positive active section 2322h is smaller than the active material capacity per unit area of the peripheral positive active section.
  • the central positive active segment 2322h is rectangular, the number of peripheral positive active segments is one, defined as the first peripheral positive active segment 2322i, the inner contour of the peripheral positive active segment It is rectangular and coincides with the outer contour of the central positive active section 2322h, and the outer contour of the peripheral positive active section is rectangular.
  • the center of the central cathode active section 2322h is the center O3 of the first cathode active material layer.
  • the number of peripheral anode active segments is three, which are a first peripheral cathode active segment 2322i, a second peripheral cathode active segment 2322j, and a third peripheral cathode active segment, respectively. 2322k.
  • the first peripheral positive active section 2322i is ringed around the central positive active section 2322h, the inner contour of the first peripheral positive active section 2322i coincides with the outer contour of the central positive active section 2322h, and the second peripheral positive active section 2322j is ringed Distributed on the first peripheral positive active section 2322i, the inner contour of the second peripheral positive active section 2322j coincides with the outer contour of the first peripheral positive active section 2322i, and the third peripheral positive active section 2322k is distributed around the second peripheral The inner contour of the positive active section 2322j and the third peripheral positive active section 2322k coincide with the outer contour of the second peripheral positive active section 2322j, and the outer contour of the third peripheral positive active section 2322k is rectangular.
  • the center of the central cathode active section 2322h is the center O3 of the first cathode active material layer.
  • the outer contour of the central positive active section 2322h is rectangular, the inner and outer contours of the first peripheral positive active section 2322i are rectangular, the inner and outer contours of the second peripheral positive active section 2322j are rectangular, and the third outer positive active section 2322j is rectangular. Both the inner and outer contours of the peripheral positive active section 2322k are rectangular.
  • the outer contour of the central positive active section 2322h is elliptical, which can be closer to the expansion and deformation state of the first positive active material layer 2322 when the abutting area B1 abuts against the casing 21 . , which is beneficial to reduce the risk of lithium precipitation caused by the extrusion of the electrolyte when the abutting area B1 and the casing 21 abut.
  • the particle size of the active material of the first positive electrode active material layer 2322 is larger than the particle size of the active material of the second positive electrode active material layer 2323 .
  • the diffusion rate of lithium ions in the first positive electrode active material layer is low, and the rate of lithium ions coming out from the first positive electrode active material layer is also reduced, which can reduce the amount of lithium leaching out from the first positive electrode active material layer.
  • the risk of ions gathering in the first negative electrode active material layer makes the first negative electrode active material layer less likely to precipitate lithium.
  • the particle size of the active material in the positive active section of each first positive active material layer 2322 is larger, which is closer to the center O3 of the first positive active material layer.
  • the central cathode active section 2322h is the section with the largest particle size of the active material in the first cathode active material layer 2322, and the particle size of the active material in the central cathode active section 2322h is K, then the particle size of the active material in the first peripheral cathode active section 2322i, the particle size of the active material in the second peripheral cathode active section 2322j, and the particle size of the active material in the third peripheral cathode active section 2322k 0.8K, 0.6K and 0.4K respectively.
  • the active material capacities per unit area of the first positive active material layers 2322 on the two surfaces of the positive electrode current collector 2321 are different.
  • the active material capacity per unit area of the first positive electrode active material layer 2322 on the surface of the positive electrode current collector 2321 on the side closer to the thickness center plane B is smaller than that on the surface of the positive electrode current collector 2321 on the side farther from the thickness center plane B.
  • the active material capacity per unit area of the first positive electrode active material layer 2322 that is, in the abutment area B1 in 24 in the figure, the active material capacity per unit area of the inner positive electrode active material layer 2322m of the positive electrode current collector 2321 is greater than that of the positive electrode current collector 2321.
  • the inner and outer sides of the positive electrode current collector 2321 are relative to the thickness center plane B, the side closer to the thickness center plane B is the inner side, and the side farther from the thickness center plane B is the outer side.
  • both the negative electrode sheet 231 and the positive electrode sheet 232 may be improved, so that the active material capacity per unit area of the first negative electrode active material layer 2312 is greater than that of the second negative electrode active material layer 2313 and the active material capacity per unit area of the first positive electrode active material layer 2322 is smaller than the active material capacity per unit area of the second positive electrode active material layer 2323 .
  • an embodiment of the present application also provides a method for manufacturing an electrode assembly 23, including:
  • the negative electrode sheet 231 includes a plurality of first negative electrode active material layers 2312 located in the abutting region B1 and arranged in layers along the thickness direction X, and a plurality of second negative electrode active material layers located in the non-abutting region B2 and arranged in layers along the thickness direction X layer 2313;
  • the positive electrode sheet 232 includes a plurality of first positive electrode active material layers 2322 located in the abutting region B1 and arranged in layers along the thickness direction X and a plurality of second positive electrode active material layers located in the non-abutting region B2 and arranged in layers in the thickness direction X material layer 2323;
  • the active material capacity per unit area of the first negative electrode active material layer 2312 is greater than the active material capacity per unit area of the second negative electrode active material layer 2313; and/or the active material capacity per unit area of the first positive electrode active material layer 2322 is less than The active material capacity per unit area of the second positive electrode active material layer 2323 .
  • an embodiment of the present application further provides a manufacturing equipment 400 for an electrode assembly, including: a providing device 410 for providing a positive electrode sheet 232 and a negative electrode sheet 231 ; an assembling device 420 for combining the positive electrode sheet 232 and the negative electrode sheet
  • the sheets 231 are stacked and wound to form a winding structure, so that the electrode assembly 23 includes abutting regions B1 on both sides of its thickness center plane B for abutting against the case 21 and non-abutting regions B1 for not abutting against the case 21 .
  • the thickness center plane B is perpendicular to the thickness direction X of the electrode assembly 23 and passes through the winding axis;
  • the negative electrode sheet 231 includes a plurality of first negative electrode active materials located in the abutment area B1 and arranged in layers along the thickness direction X layer 2312 and a plurality of second negative electrode active material layers 2313 located in the non-abutting region B2 and arranged in layers along the thickness direction X;
  • the positive electrode sheet 232 includes a plurality of first negative electrode active material layers located in the abutting region B1 and arranged in layers in the thickness direction X
  • the active material capacity per unit area of the first negative electrode active material layer 2312 is greater than that of the second negative electrode active material layer

Landscapes

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

Abstract

本申请提供了一种电极组件、电池单体、电池、用电设备、电极组件的制造方法及设备，涉及电池技术领域。电极组件包括正极片和负极片，电极组件包括位于其厚度中心面两侧的抵靠区和非抵靠区；负极片包括位于抵靠区的多个第一负极活性物质层和位于非抵靠区多个第二负极活性物质层；正极片包括位于抵靠区的多个第一正极活性物质层和位于非抵靠区的多个第二正极活性物质层；第一负极活性物质层的单位面积活性物质容量大于第二负极活性物质层的单位面积活性物质容量；和/或，第一正极活性物质层的单位面积活性物质容量小于第二正极活性物质层的单位面积活性物质容量，从而能够有效降低抵靠区与壳体抵靠时因电解液被挤出而造成析锂的风险。

Description

电极组件、电池单体、电池及用电设备 技术领域
本申请涉及电池技术领域，特别是涉及一种电极组件、电池单体、电池、用电设备、电极组件的制造方法及设备。
背景技术
随着智能手机、平板电脑和电动汽车等的迅猛发展，锂离子电池的应用也日益广泛，因此对锂电池也提出了更高的要求。人们在注重电池安全性能的同时还要求锂电池具有更好的电性能表现。而析锂即是影响电池的电性能和安全性能的主要因素的之一，电芯一旦发生析锂，不但会降低电池的电性能，而且随着析锂量的累加，容易形成枝晶，枝晶有可能会刺破隔膜，而引发电池内短路，造成安全隐患。
因此，如何有效避免或降低电池析锂的风险，成为目前亟待解决的技术问题。
发明内容
本申请实施例提供一种电极组件、电池单体、电池、用电设备、电极组件的制造方法及设备，以有效降低电池析锂的风险。
第一方面，本申请实施例提供一种电极组件，用于容纳于壳体，所述电极组件包括正极片和负极片，所述正极片和所述负极片层叠设置并绕卷绕轴线卷绕；所述电极组件包括位于其厚度中心面两侧的用于与所述壳体抵靠的抵靠区和不与所述壳体抵靠的非抵靠区，所述厚度中心面垂直于所述电极组件的厚度方向且经过所述卷绕轴线；所述负极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一负极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二负极活性物质层；所述正极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一正极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二正极活性物质层；所述第一负极活性物质层的单位面积活性物质容量大于所述第二负极活性物质层的单位面积活性物质容量；和/或，所述第一正极 活性物质层的单位面积活性物质容量小于所述第二正极活性物质层的单位面积活性物质容量。
上述技术方案中，若从正极脱嵌的锂离子无法进入负极，则锂离子只能析出在负极表面，从而形成灰色的物质，即析锂。当不与壳体抵靠的非抵靠区的第二负极活性物质层的单位面积活性物质容量满足设计要求时，即非抵靠区的第二负极活性物质层的单位面积活性物质容量达到第一预设值使得非抵靠区的第二负极活性物质层不易出现析锂。当位于抵靠区的第一负极活性物质层的单位面积活性物质容量大于位于非抵靠区的第二负极活性物质层的单位面积活性物质容量，即第一负极活性物质层的单位面积活性物质容量大于第一预设值时，相当于增大了第一负极活性物质层的单位面积活性物质容量，则第一负极活性物质层能够接受从第一正极活性物质层脱出的锂离子，抵靠区的第一负极活性物质层出现析锂的可能性较小，从而能够有效降低抵靠区与壳体抵靠时因电解液被挤出而造成析锂的风险。
当不与壳体抵靠的非抵靠区的第二正极活性物质层的单位面积活性物质容量满足设计要求时，即非抵靠区的第二正极活性物质层的单位面积活性物质容量达到第二预设值使得非抵靠区的第二负极活性物质层不易出现析锂。当位于抵靠区的第一正极活性物质层的单位面积活性物质容量小于位于非抵靠区的第二正极活性物质层的单位面积活性物质容量，即第一正极活性物质层的单位面积活性物质容量小于第二预设值，相当于降低了第一正极活性物质层的单位面积活性物质容量，则第一负极活性物质层能够接受从第一正极活性物质层脱出的锂离子，抵靠区的第一负极出现析锂的可能性较小，从而能够有效降低因抵靠区与壳体抵靠时电解液被挤出而造成析锂的风险。
在第一方面的一些实施例中，所述第一负极活性物质层的活性材料的克容量大于所述第二负极活性物质层的活性材料的克容量；和/或，所述第一正极活性物质层的活性材料的克容量小于所述第二正极活性物质层的活性材料的克容量。
上述技术方案中，通过增大抵靠区的第一负极活性物质层的活性材料的克容量，可增大抵靠区的第一负极活性物质层的单位面积活性物质容量，以使抵靠区的第一负极活性物质层的单位面积容量大于非抵靠区的第二负极活性物质的单位面积容量；和/或，通过减小抵靠区的第一正极活性物质层的活性材料的克容量，可减小抵靠区的第一正极活性物质层的单位面积活性物质容量，以使抵靠区的第一正极活性物质层的单位面积容量小于非抵靠区的第二正极活性物质的单位 面积容量，能够有效降低因抵靠区与壳体抵靠时电解液被挤出而造成析锂的风险。
在第一方面的一些实施例中，所述第一负极活性物质层的活性材料的重量与所述第一负极活性物质层的重量的比值大于所述第二负极活性物质层的活性材料的重量与所述第二负极活性物质层的重量的比值；和/或，所述第一正极活性物质层的活性材料的重量与所述第一正极活性物质层的重量的比值小于所述第二正极活性物质层的活性材料的重量与所述第二正极活性物质层的重量的比值。
上述技术方案中，通过增加抵靠区的第一负极活性物质层中的活性材料，提高抵靠区的第一负极活性物质层中活性材料的重量比，从而增大抵靠区的第一负极活性物质层的单位面积活性物质容量；和/或通过减少抵靠区的第一正极活性物质层中的活性材料，降低抵靠区的第一正极活性物质层中活性材料的重量比，从而降低抵靠区的第一正活性物质层的单位面积活性物质容量，能够有效降低因抵靠区与壳体抵靠时电解液被挤出而造成析锂的风险。
在第一方面的一些实施例中，相邻的两个第一负极活性物质层中的一个第一负极活性物质层的单位面积活性物质容量大于另一个第一负极活性物质层的单位面积活性物质容量，所述另一个第一负极活性物质层相较于所述一个第一负极活性物质层更靠近所述厚度中心面；和/或，相邻的两个第一正极活性物质层中的一个第一正极活性物质层的单位面积活性物质容量小于另一个第一正极活性物质层的单位面积活性物质容量，所述另一个第一正极活性物质层相较于所述一个第一正极活性物质层更靠近所述厚度中心面。
上述技术方案中，在抵靠区，越靠近壳体的第一负极活性物质层或者第一正极活性物质层被挤压越严重，相邻的两个第一负极活性物质层中壳体较近厚度中心面较远的一个的单位面积活性物质容量大于另一个的单位面积活性物质容量；和/或相邻的两个第一正极活性物质层中壳体较近厚度中心面较远的一个的单位面积活性物质容量小于另一个的单位面积活性物质容量，能够进一步有效降低因抵靠区与壳体抵靠时电解液被挤出而造成析锂的风险。
在第一方面的一些实施例中，相邻的两个第一负极活性物质层中的一个第一负极活性物质层的活性材料的克容量大于另一个第一负极活性物质层的活性材料的克容量，所述另一个第一负极活性物质层相较于所述一个第一负极活性物质层更靠近所述厚度中心面；和/或，相邻的两个第一正极活性物质层中的一个的第一正极活性物质层的活性材料的克容量小于另一个第一正极活性物质层的活性材 料的克容量，所述另一个第一正极活性物质层相较于所述一个第一正极活性物质层更靠近所述厚度中心面。
上述技术方案中，通过增大相邻的两个第一负极活性物质层中较为靠近壳体的一个第一负极活性物质层的活性材料的克容量，可增大该第一负极活性物质层的单位面积活性物质容量，以使相邻的两个第一负极活性物质层中较为靠近壳体的一个第一负极活性物质层的单位面积活性物质容量大于另一个第一负极活性物质层的单位面积活性物质容量；和/或，通过减小相邻的两个第一正极活性物质层中较为靠近壳体的一个第一正极活性物质层的活性材料的克容量，可减小该第一正极活性物质层的单位面积活性物质容量，以使相邻的两个第一正极活性物质层中较为靠近壳体的一个第一正极活性物质层的单位面积活性物质容量小于另一个第一正极活性物质层的单位面积活性物质容量，能够进一步有效降低因抵靠区与壳体抵靠时电解液被挤出而造成析锂的风险。
在第一方面的一些实施例中，相邻的两个第一负极活性物质层中的一个第一负极活性物质层的活性材料的重量与所述一个第一负极活性物质层的重量的比值大于另一个第一负极活性物质层的活性材料的重量与所述另一个第一负极活性物质层的重量的比值，所述另一个第一负极活性物质层相较于所述一个第一负极活性物质层更靠近于所述厚度中心面；和/或，相邻的两个第一正极活性物质层中的一个第一正极活性物质层的活性材料的重量与所述一个第一正极活性物质层的重量的比值小于另一个第一正极活性物质层的活性材料的重量与所述另一个第一正极活性物质层的重量的比值，所述另一个第一正极活性物质层相较于所述一个第一正极活性物质层更靠近所述厚度中心面。
上述技术方案中，通过增加相邻的两个第一负极活性物质层中较为靠近壳体的一个第一负极活性物质层中的活性材料，能够提高该第一负极活性物质层中活性材料的重量比，从而增大相邻的两个第一负极活性物质层中较为靠近壳体的一个第一负极活性物质层的单位面积活性物质容量；和/或通过减小相邻的两个第一正极活性物质层中较为靠近壳体的一个第一正极活性物质层中的活性材料，能够降低该第一正极活性物质层中的活性材料的重量比，从而降低相邻的两个第一负极活性物质层中较为靠近壳体的一个第一正极活性物质层的单位面积活性物质容量，能够有效降低因抵靠区中挤压较为严重的位置电解液被挤出而造成析锂的风险。
在第一方面的一些实施例中，所述第一负极活性物质层包括多个负极活性区段，所述第一正极活性物质层均包括多个正极活性区段；相邻的两个负极活性区段中的一个负极活性区段的单位面积活性物质容量大于另一个负极活性区段的单位面积活性物质容量，所述一个负极活性区段相较于所述另一个负极活性区段更靠近所述第一负极活性物质层的中心；和/或，相邻的两个正极活性区段中的一个区段的单位面积活性物质容量小于另一个正极活性区段的单位面积活性物质容量，所述一个正极活性区段相较于所述另一个正极活性区段更靠近所述第一正极活性物质层的中心。
上述技术方案中，第一负极活性物质层和第一正极活性物质层越靠近各自中心的位置挤压越严重，因此，相邻的两个负极活性区段中较为靠近第一负极活性物质层的中心的一个负极活性区段的单位面积活性物质容量大于另一个负极活性区段的单位面积活性物质容量，和/或相邻的两个正极活性区段中较为靠近第一正极活性物质层的中心的一个正极活性区段的单位面积活性物质容量小于另一个正极活性区段的单位面积活性物质容量，能够进一步有效降低因抵靠区与壳体抵靠时电解液被挤出而造成析锂的风险。
在第一方面的一些实施例中，相邻的两个负极活性区段中的一个负极活性区段的活性材料的克容量大于另一个负极活性区段中的活性材料的克容量，所述一个负极活性区段相较于所述另一个负极活性区段更靠近所述第一负极活性物质层的中心；和/或，相邻的两个正极活性区段中的一个正极活性区段的活性材料的克容量小于另一个正极活性区段的活性材料的克容量，所述一个正极活性区段相较于所述另一个正极活性区段更靠近所述第一正极活性物质层的中心。
上述技术方案中，通过增大相邻的两个负极活性区段中较为靠近第一负极活性物质层的中心的一个负极活性区段的活性材料的克容量，可增大该负极活性区段的单位面积活性物质容量，以使相邻的两个负极活性区段中较为靠近第一负极活性物质层的中心的一个负极活性区段的单位面积活性物质容量大于另一个负极活性区段的单位面积活性物质容量；和/或，通过减小相邻的两个正极活性区段中较为靠近第一正极活性物质层的中心的一个正极活性区段的活性材料的克容量，可降低该正极活性区段的单位面积活性物质容量，以使相邻的两个正极活性区段中较为靠近第一正极活性物质层的中心的一个正极活性区段的单位面积活性物质容量大于另一个正极活性区段的单位面积活性物质容量，能够有效降低因抵靠区与壳体抵靠时电解液被挤出而造成析锂的风险。
在第一方面的一些实施例中，相邻两个负极活性区段中的一个负极活性区段的活性材料的重量与所述一个负极活性区段的重量的比值大于另一个负极活性区段的活性材料的重量与所述另一个负极活性区段的重量的比值，所述一个负极活性区段相较于所述另一个负极活性区段更靠近所述第一负极活性物质层的中心；和/或，相邻两个正极活性区段中的一个正极活性区段的活性材料的重量与所述一个正极活性区段的重量的比值小于另一个正极活性区段的活性材料的重量与所述另一个正极活性区段的重量的比值，所述一个正极活性区段相较于所述另一个正极活性区段更靠近所述第一正极活性物质层的中心。
上述技术方案中，通过增加相邻的两个负极活性区段中较为靠近第一负极活性物质层的中心的一个负极活性区段中的活性材料，能够提高该负极活性区段中活性材料的重量比，从而增大该负极活性区段的单位面积活性物质容量；和/或通过减小相邻的两个正极活性区段中较为靠近第一正极活性物质层的中心的一个正极活性区段中的活性材料，能够该正极活性区段中活性材料的重量比，从而降低该正极活性区段的单位面积活性物质容量，能够有效降低因抵靠区与壳体抵靠时电解液被挤出而造成析锂的风险。
在第一方面的一些实施例中，每个负极活性区段呈条状，所述多个负极活性区段沿所述卷绕轴线的方向排列；和/或，每个正极活性区段呈条状，所述多个正极活性区段沿所述卷绕轴线的方向排列。
上述技术方案中，负极活性区段和/或正极活性区段呈条状，负极活性物质层涂覆方便。
在第一方面的一些实施例中，所述多个负极活性区段包括中央负极活性区段和至少一个外围负极活性区段，每个外围负极活性区段呈环状且围绕所述中央负极活性区段，所述中央负极活性区段和所述至少一个外围负极活性区段以所述第一负极活性物质层的中心呈辐射状分布；和/或，所述多个正极活性区段包括中央正极活性区段和至少一个外围正极活性区段，每个外围正极活性区段呈环状且围绕所述中央正极活性区段，所述中央正极活性区段和所述至少一个外围正极活性区段以所述第一正极活性物质层的中心呈辐射状分布。
上述技术方案中，每个负极活性区段环布于第一负极活性物质层的中心，则沿任意方向，相邻的两个负极活性区段中靠近中心的一个的负极活性区段的单位面积活性物质容量均大于另一个负极活性区段的单位面积活性物质的容量；和/或每个正极活性区段环布于第一正极活性物质层的中心，则沿任意方向，相邻的 两个正极活性区段中靠近中心的一个的正极活性区段的单位面积活性物质容量均小于另一个正极活性区段的单位面积活性物质的容量，能够进一步降低因抵靠区中挤压较为严重的位置电解液被挤出而造成析锂的风险。
在第一方面的一些实施例中，所述中央负极活性区段和/或所述中央正极活性区段呈椭圆形。
上述技术方案中，中央负极活性区段和/中央正极活性区段呈椭圆形，能够更加贴近抵靠区与壳体抵靠时第一负极活性物质层和第一正极活性物质层的膨胀形变状态，有利于降低因抵靠区与壳体抵靠时电解液被挤出而造成析锂的风险。
第二方面，本申请实施例提供一种电池单体，包括：壳体和根据第一方面实施例提供的电极组件，所述电极组件容纳于所述壳体内，所述抵靠区用于与所述壳体抵靠，所述非抵靠区用于不与所述壳体抵靠。
上述技术方案中，使电极组件的抵靠区的第一负极活性物质层的单位面积活性物质容量大于非抵靠区的第二负极活性物质层的单位面积活性物质容量；和/或电极组件的抵靠区的第一正极活性物质层的单位面积活性物质容量小于非抵靠区的第二正极活性物质层的单位面积活性物质容量，能够有效降低电池单体工作时，因抵靠区与壳体抵靠导致电解液被挤出而造成析锂的风险。
第二方面的一些实施例中，所述电池单体包括两个所述电极组件，两个所述电极组件沿所述厚度方向并排布置，两个所述电极组件的所述抵靠区相背离设置。
上述技术方案中，两个电极组件沿厚度方向并排布置必然会有两个区域可能与壳体的内抵靠，两个电极组件的抵靠区相背离设置，反之两个电极组件的非抵靠区相靠近设置，则两个电极组件的抵靠区均能够与壳体抵靠，能够有效降低电池单体工作时，因电极组件的布置方向上的两端的抵靠区与壳体抵靠导致电解液被挤出而造成析锂的风险。
第三方面，本申请实施例提供一种电池，包括第二方面任一实施例提供的电池单体。
上述技术方案中，使电极组件的抵靠区的第一负极活性物质层的单位面积活性物质容量大于非抵靠区的第二负极活性物质层的单位面积活性物质容量；和/或电极组件的抵靠区的第一正极活性物质层的单位面积活性物质容量小于非抵靠 区的第二正极活性物质层的单位面积活性物质容量，能够有效降低电池工作时，因电极组件的抵靠区与壳体抵靠导致电解液被挤出而造成析锂的风险。
第四方面，本申请实施例提供一种用电设备，包括第二方面任一实施例提供的电池单体。
第五方面，本申请实施例提供一种电极组件的制造方法，包括：提供正极片和负极片；将所述负极片和所述正极片层叠设置并绕卷绕轴线卷绕形成卷绕结构，以使所述电极组件包括位于其厚度中心面两侧的用于与壳体抵靠的抵靠区和不与所述壳体抵靠的非抵靠区，所述厚度中心面垂直于所述电极组件的厚度方向且经过所述卷绕轴线；其中，所述负极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一负极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二负极活性物质层；所述正极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一正极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二正极活性物质层；所述第一负极活性物质层的单位面积活性物质容量大于所述第二负极活性物质层的单位面积活性物质容量；和/或，所述第一正极活性物质层的单位面积活性物质容量小于所述第二正极活性物质层的单位面积活性物质容量。
第六方面，本申请实施例提供一种电极组件的制造设备，包括：提供装置，用于提供正极片和负极片；组装装置，用于将所述正极片和所述负极片层叠设置并绕卷绕轴线卷绕形成卷绕结构，以使所述电极组件包括位于其厚度中心面两侧的用于与壳体抵靠的抵靠区和不与所述壳体抵靠的非抵靠区，所述厚度中心面垂直于所述电极组件的厚度方向且经过所述卷绕轴线；其中，所述负极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一负极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二负极活性物质层；所述正极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一正极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二正极活性物质层；所述第一负极活性物质层的单位面积活性物质容量大于所述第二负极活性物质层的单位面积活性物质容量；和/或，所述第一正极活性物质层的单位面积活性物质容量小于所述第二正极活性物质层的单位面积活性物质容量。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，应当理解，以下附图仅示出了本申请的某些实施例，因此不应被看作是对范围的限定，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他相关的附图。
图1为本申请一些实施例提供的车辆的结构示意图；
图2为本申请一些实施例提供的电池的结构示意图；
图3为本申请一些实施例提供的电池单体的爆炸图；
图4为本申请一些实施例提供的组装后的电池单体的结构示意图；
图5为图4中P0-P0向剖视图；
图6为本申请一些实施例提供的电极组件的结构示意图；
图7为图6中P1-P1向剖视图；
图8为本申请另一些实施例提供的电极组件的结构示意图；
图9为本申请又一些实施例提供的电极组件的结构示意图(第一负极活性物质层包括多个负极活性区段)；
图10为本申请一些实施例提供的第一负极活性物质层的结构示意图；
图11为本申请又一些实施例提供的第一负极活性物质层的结构示意图；
图12为本申请另一些实施例提供的第一负极活性物质层的结构示意图；
图13为本申请再一些实施例提供的第一负极活性物质层的结构示意图；
图14为本申请再一些实施例提供的第一负极活性物质层的结构示意图(中央负极活性区段为椭圆形)；
图15为本申请再一些实施例提供的电极组件的结构示意图；
图16为本申请又一些实施例提供的电极组件的结构示意图；
图17为本申请另一些实施例提供的电极组件的结构示意图；
图18为本申请再一些实施例提供的电极组件的结构示意图(第一正极活性物质层包括多个正极活性区段)；
图19为本申请一些实施例提供的第一正极活性物质层的结构示意图；
图20为本申请又一些实施例提供的第一正极活性物质层的结构示意图；
图21为本申请另一些实施例提供的第一正极活性物质层的结构示意图；
图22为本申请再一些实施例提供的第一正极活性物质层的结构示意图；
图23为本申请再一些实施例提供的第一正极活性物质层的结构示意图(中央正极活性区段为椭圆形)；
图24为本申请又一些实施例提供的电极组件的结构示意图(正极集流体两个表面的第一正极活性物质层的单位面积活性物质容量不同)；
图25为本申请另一些实施例提供的电极组件的结构示意图(第一负极活性物质层和第一正极活性物质层均改进)；
图26为本申请一些实施例提供的电极组件的制造方法的流程图；
图27为本申请一些实施例提供的电极组件的制造设备的结构框图。
标记说明：1000-车辆；100-电池；10-箱体；11-第一箱体部；12-第二箱体部；20-电池单体；21-壳体；211-侧壁；22-端盖组件；23-电极组件；231-负极片；2311-负极集流体；2312-第一负极活性物质层；2312a-第一负极活性区段；2312b-第二负极活性区段；2312c-第三负极活性区段；2312d-第四负极活性区段；2312e-第五负极活性区段；2312f-第六负极活性区段；2312g-第七负极活性区段；2312h-中央负极活性区段；2312i-第一外围负极活性区段；2312j-第二外围负极活性区段；2312k-第三外围负极活性区段；2312m-内层负极活性物质层；2312n-外层负极活性物质层；2313-第二负极活性物质层；232-正极片；2321-正极集流体；2322-第一正极活性物质层；2322a-第一正极活性区段；2322b-第二正极活性区段；2322c-第三正极活性区段；2322d-第四正极活性区段；2322e-第五正极活性区段；2322f-第六正极活性区段；2322g-第七正极活性区段；2322h-中央正极活性区段；2322i-第一外围正极活性区段；2322j-第二外围正极活性区段；2322k-第三外围正极活性区段；2322m-内层正极活性物质层；2322n-外层正极活性物质层；2323-第二正极活性物质层；233-隔膜；X-厚度方向；Y-卷绕方向；Z-卷绕轴线方向；A0-平直区；A1-弯折区；B-厚度中心面；B1-抵靠区；B2-非抵靠区；O1-第一负极活性物质层的中心；O2-第一负极活性物质层的中心面；O3-第一正极活性物质层的中心；O4-第一正极活性物质层的中心面；200-控制器；300-马达；400-电极组件的制造设备；410-提供装置；420-组装装置。
具体实施方式
下面结合附图和实施例对本申请的实施方式作进一步详细描述。以下实施例的详细描述和附图用于示例性地说明本申请的原理，但不能用来限制本申请的 范围，即本申请不限于所描述的实施例。
在本申请的描述中，需要说明的是，除非另有说明，“多个”的含义是两个以上；术语“上”、“下”、“左”、“右”、“内”、“外”等指示的方位或位置关系仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的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的限制。此外，术语“第一”、“第二”、“第三”等仅用于描述目的，而不能理解为指示或暗示相对重要性。“垂直”并不是严格意义上的垂直，而是在误差允许范围之内。“平行”并不是严格意义上的平行，而是在误差允许范围之内。
下述描述中出现的方位词均为图中示出的方向，并不是对本申请的具体结构进行限定。在本申请的描述中，还需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是直接相连，也可以通过中间媒介间接相连。对于本领域的普通技术人员而言，可视具体情况理解上述术语在本申请中的具体含义。
本申请中出现的“多个”指的是两个以上(包括两个)。
本申请中，电池单体可以包括锂离子二次电池、锂离子一次电池、锂硫电池、钠锂离子电池、钠离子电池或镁离子电池等，本申请实施例对此并不限定。电池单体可呈圆柱体、扁平体、长方体或其它形状等，本申请实施例对此也不限定。电池单体一般按封装的方式分成三种：柱形电池单体、方体方形电池单体和软包电池单体，本申请实施例对此也不限定。
本申请的实施例所提到的电池是指包括一个或多个电池单体以提供更高的电压和容量的单一的物理模块。例如，本申请中所提到的电池可以包括电池模块或电池包等。电池一般包括用于封装一个或多个电池单体的箱体。箱体可以避免液体或其他异物影响电池单体的充电或放电。
电池单体包括电极组件和电解液，电极组件由正极片、负极片和隔膜组成。电池单体主要依靠金属离子在正极片和负极片之间移动来工作。正极片包括正极集流体和正极活性物质层，正极活性物质层涂覆于正极集流体的表面，未涂敷正极活性物质层的正极集流体凸出于已涂覆正极活性物质层的正极集流体，未涂敷正极活性物质层的正极集流体作为正极极耳。以锂离子电池为例，正极集流体的材料可以为铝，正极活性物质可以为钴酸锂、磷酸铁锂、三元锂或锰酸锂 等。负极片包括负极集流体和负极活性物质层，负极活性物质层涂覆于负极集流体的表面，未涂敷负极活性物质层的负极集流体凸出于已涂覆负极活性物质层的负极集流体，未涂敷负极活性物质层的负极集流体作为负极极耳。负极集流体的材料可以为铜，负极活性物质可以为碳或硅等。为了保证通过大电流而不发生熔断，正极极耳的数量为多个且层叠在一起，负极极耳的数量为多个且层叠在一起。隔离膜的材质可以为PP(polypropylene，聚丙烯)或PE(polyethylene，聚乙烯)等。此外，电极组件可以是卷绕式结构，也可以是叠片式结构，本申请实施例并不限于此。
电池技术的发展要同时考虑多方面的设计因素，例如，能量密度、循环寿命、放电容量、充放电倍率等性能参数，另外，还需要考虑电池的安全性。而析锂即是影响电池的电性能和安全性能的主要因素的之一，一旦发生析锂，不但会降低电池的电性能，而且随着析锂量的累加，容易形成枝晶，枝晶有可能会刺破隔膜，而引发电池内短路，造成安全隐患。造成析锂的原因有很多。
发明人发现，对包括沿厚度方向并排布置的多个电极组件的电池单体来说，位于厚度方向的两端的两个电极组件在热膨胀时有一侧会与电池单体的壳体的内壁抵靠，在壳体的内壁的束缚下，电极组件与壳体抵靠的一侧的应力无法释放，导致电解液被挤出的程度大于电极组件未与壳体抵靠的一侧，电解液挤出程度较大的一侧会出现电解液浸润不足，从而出现负极片的空隙变小、锂离子在负极片内部的扩散阻力变大等问题，进而导致析锂。
鉴于此，本申请实施例提供一种技术方案，通过使电极组件用于与壳体抵靠的抵靠区的第一负极活性物质层的单位面积活性物质容量大于未与壳体抵靠的非抵靠区的第二负极活性物质层的单位面积活性物质容量，和/或，使抵靠区的第一正极活性物质层的单位面积活性物质容量小于非抵靠区的第二正极活性物质层的单位面积活性物质容量，以有效降低因抵靠区与壳体抵靠时电解液被挤出而造成析锂的风险。
本申请实施例描述的技术方案适用于电池以及使用电池的用电设备。
用电设备可以是车辆、手机、便携式设备、笔记本电脑、轮船、航天器、电动玩具和电动工具等等。车辆可以是燃油汽车、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；航天器包括飞机、火箭、航天飞机和宇宙飞船等等；电动玩具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；电动工具包括 金属切削电动工具、研磨电动工具、装配电动工具和铁道用电动工具，例如，电钻、电动砂轮机、电动扳手、电动螺丝刀、电锤、冲击电钻、混凝土振动器和电刨等等。本申请实施例对上述用电设备不做特殊限制。
以下实施例为了方便说明，以用电设备为车辆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。
如图2所示，电池100包括箱体10和电池单体20，电池单体20收容于箱体10内，箱体10为电池单体20提供容纳空间，箱体10包括第一箱体部11和第二箱体部12，第一箱体部11和第二箱体部12被配置为共同限定出用于收容电池单体20的容纳空间。在电池100中，电池单体20可以是一个、也可以是多个。若电池单体20为多个，多个电池单体20之间可串联或并联或混联，混联是指多个电池单体20中既有串联又有并联。多个电池单体20之间可直接串联或并联或混联在一起，再将多个电池单体20构成的整体容纳于箱体10内；当然，也可以是多个电池单体20先串联或并联或混联组成电池模块，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体10内。电池单体20可呈圆柱体、扁平体或其它形状等。
在一些实施例中，电池100还可以包括汇流部件(图中未示出)，多个电池单体20之间可通过汇流部件实现电连接，以实现多个电池单体20的串联或并联或混联。
请参照图3、图4，图3示出的是本申请一些实施例提供的电池单体20的爆炸图，图4示出的是电池单体20组装后的结构示意图。电池单体20包括壳体21、端盖组件22和电极组件23，壳体21具有开口，电极组件23容纳于外壳内，端盖组件22用于封盖于开口。壳体21可以是多种形状，比如，圆柱体、扁平状等。外壳的形状可根据电极组件23的具体形状来确定，比如，电极组件23为扁 平状结构，外壳则可选用长方体结构。外壳的材质也可以是多种，比如，铜、铁、铝、不锈钢、铝合金等，本申请实施例对此不作特殊限制。
电池单体20的电极组件23的数量为多个。图3和图4示例性的示出了外壳为长方体和两个电极组件23为扁平状的电池单体20。在图3中，电极组件23的数量为两个，沿电极组件23的厚度方向X，两个电极组件23并排布置。
如图5所示，壳体21具有沿电极组件23的厚度方向X相对布置的两个侧壁211，两个电极组件23中的一个电极组件23靠近一个侧壁211设置，另一个电极组件23靠近另一个侧壁211设置。
在一些实施例中，电池单体20还包括至少一个电芯，沿厚度方向X，所述的至少一个电芯位于两个电极组件23之间。电芯的结构可以与本申请实施例提供的电极组件23结构相同，也可以参照现有电芯设计，在此不再赘述。
在一些实施例中，如图6、图7所示，电极组件23包括负极片231、正极片232和隔膜233。正极片232、负极片231和隔膜233层叠设置并绕卷绕轴线卷绕形成卷绕式电极组件23。
负极片231包括负极集流体2311、涂覆于负极集流体2311的两个表面的第一负极活性物质层2312和涂覆于负极集流体2311的两个表面的第二负极活性物质层2313。第一负极活性物质层2312的数量为多个，第二负极活性物质层2313的数量为多个。沿电极组件23的卷绕方向Y，第一负极活性物质层2312和第二负极活性物质层2313交替分布。
正极片232包括正极集流体2321、涂覆于正极集流体2321的两个表面的第一正极活性物质层2322和涂覆于正极集流体2321的两个表面的第二正极活性物质层2323。第一正极活性物质层2322的数量为多个，第二正极活性物质层2323的数量为多个。沿电极组件23的卷绕方向Y，第一正极活性物质层2322和第二正极活性物质层2323交替分布。
隔膜233用于将负极片231和正极片232隔开，以防止短路。隔膜233具有大量贯通的微孔，能够保证电解质离子自由通过，对锂离子有很好的穿透性。隔膜233的材质可以为PP或者PE等。
电极组件23具有平直区A0和两个弯折区A1，两个弯折区A1分别连接于平直区A0的两端。第一负极活性物质层2312、第一正极活性物质层2322、第二负极活性物质层2313和第二正极活性物质层2323均位于平直区A0，并在平直区A0内沿厚度方向X层叠布置。
电极组件23包括位于其厚度中心面B两侧的用于与壳体21(图5中示出)抵靠的抵靠区B1和不与壳体21(图5中示出)抵靠的非抵靠区B2，其中厚度中心面B垂直于电极组件23的厚度方向X且经过卷绕轴线。所有的第一负极活性物质层2312和所有的第一正极活性物质层2322位于抵靠区B1并沿厚度方向X层叠布置，所有的第二负极活性物质层2313和所有的第二正极活性物质层2323位于非抵靠区B2并沿厚度方向X层叠布置。
可以理解地，平直区A0位于电极组件23的厚度中心面B两侧的两个部分分别位于抵靠区B1和非抵靠区B2。
在一些实施例中，沿厚度方向X，任意一层负极集流体2311的两个表面的第一负极活性物质层2312的单位面积活性物质容量相同，则第一负极活性物质层2312的单位面积活性物质容量可以代表对应层的负极集流体2311两个表面上的第一负极活性物质层2312的单位面积活性物质容量。任意一层负极集流体2311的两个表面的第二负极活性物质层2313的单位面积活性物质容量相同，则第二负极活性物质层2313的单位面积活性物质容量可以代表对应层的负极集流体2311两个表面上的第二负极活性物质层2313的单位面积活性物质容量。
在一些实施例中，请继续参见图7，第一负极活性物质层2312的单位面积活性物质容量大于第二负极活性物质层2313的单位面积活性物质容量。
当不与壳体21抵靠的非抵靠区B2的第二负极活性物质层2313的单位面积活性物质容量满足设计要求时，即非抵靠区B2的第二负极活性物质层2313的单位面积活性物质容量达到第一预设值使得非抵靠区B2的第二负极活性物质层2313不易出现析锂。当位于抵靠区B1的第一负极活性物质层2312的单位面积活性物质容量大于位于非抵靠区B2的第二负极活性物质层2313的单位面积活性物质容量，即第一负极活性物质层2312的单位面积活性物质容量大于第一预设值时，相当于增大了第一负极活性物质层2312的单位面积活性物质容量，则第一负极活性物质层2312能够接受从第一正极活性物质层2322脱出的锂离子，抵靠区B1的第一负极活性物质层2312出现析锂的可能性较小，从而能够有效降低抵靠区B1与壳体21抵靠时因电解液被挤出而造成析锂的风险。
需要说明的是，第一负极活性物质层2312的单位面积活性物质容量，是指第一负极活性物质层2312的活性物质容量与第一负极活性物质层2312的总面积的比值，第二负极活性物质层2313的单位面积活性物质容量，是指第二负极活性物质层2313的活性物质容量与第二负极活性物质层2313的总面积的比值。进 一步解释为，第一负极活性物质层2312的活性物质容量为Q1，第一负极活性物质层2312的面积为S1，则第一负极活性物质层2312的单位面积容量QS1＝Q1/S1。第二负极活性物质层2313的活性物质容量为Q2，第二负极活性物质层2313的面积为S2，则第二负极活性物质层2313的单位面积容量QS2＝Q2/S2。
影响第一负极活性物质层2312的单位面积活性物质容量和第二负极活性物质层2313的单位面积活性物质容量的因素有很多，因此，可以通过较多的方式实现第一负极活性物质层2312的单位面积容量大于第二负极活性物质层2313的单位面积活性物质容量。
在一些实施例中，第一负极活性物质层2312的活性材料的克容量大于第二负极活性物质层2313的活性材料的克容量。
通过增大抵靠区B1的第一负极活性物质层2312的活性材料的克容量，可增大抵靠区B1的第一负极活性物质层2312的单位面积活性物质容量，以使抵靠区B1的第一负极活性物质层2312的单位面积容量大于非抵靠区B2的第二负极活性物质层2313的单位面积容量，能够有效降低因抵靠区B1与壳体21抵靠时电解液被挤出而造成析锂的风险。
克容量是指电池100内部活性物质所能释放出的电容量与活性物质的质量之比。克容量与第一负极活性物质层2312中的活性材料和第二负极活性物质层2313中的活性材料有关，比如，第一负极活性物质层2312的活性材料为硅的化合物，第二负极活性物质层2313的活性材料为石墨。硅的化合物的材料活性大于石墨的材料活性，以使第一负极活性物质层2312的嵌锂能力大于第二负极活性物质层2313的嵌锂能力，能够减小抵靠区B1受电解液挤出的影响。
在另一些实施例中，第一负极活性物质层2312的活性材料的重量与第一负极活性物质层2312的重量的比值大于第二负极活性物质层2313的活性材料的重量与第二负极活性物质层2313的重量的比值，以使第一负极活性物质层2312的单位面积活性物质容量大于第二负极活性物质层2313的单位面积活性物质容量。
第一负极活性物质层2312和第二负极活性物质层2313中均包括活性材料、粘接剂和导电剂，通过增加第一负极活性物质层2312中的活性材料，提高第一负极活性物质层2312中的活性材料的占比，从而增大第一负极活性物质层 2312的单位面积活性物质容量，以使第一负极活性物质层2312的单位面积活性物质容量大于第二负极活性物质层2313的单位面积活性物质容量。
在一些实施例中，也可以减小第一负极活性物质层2312中的粘接剂和导电剂的重量，以使第一负极活性物质层2312的重量降低，从而提高活性物质在第一负极活性物质层2312中的占比，相当于减小了第一负极活性物质层2312的涂布重量，不仅能够使得第一负极活性物质层2312中的活性材料的重量与第一负极活性物质层2312的重量的比值大于第二负极活性物质层2313的活性材料的重量与第二负极活性物质层2313的重量的比值，还能降低第一负极活性物质层2312对电解液的需求，通过更少量的电解液即可实现第一负极活性物质层2312的浸润，够减小第一负极活性物质层2312受电解液挤出的影响。
在抵靠区B1，沿厚度方向X，越靠近壳体21(图5中示出)的位置与壳体21挤压程度越严重。
基于此，如图8所示，在一些实施例中，沿厚度方向X，相邻的两个第一负极活性物质层2312中的一个第一负极活性物质层2312的单位面积活性物质容量大于另一个第一负极活性物质层2312的单位面积活性物质容量，所述的另一个第一负极活性物质层2312相较于所述的一个第一负极活性物质层2312更靠近厚度中心面B。可以理解地，在抵靠区B1，沿厚度方向X，距离厚度中心面B越远(距离壳体21的侧壁211越近)的第一负极活性物质层2312的单位面积活性物质容量越大，能够进一步有效降低因抵靠区B1与壳体21抵靠时电解液被挤出而造成析锂的风险。
同样地，可以通过较多的方式实现相邻的两个第一负极活性物质层2312中较为靠近壳体21的侧壁211的一个第一负极活性物质层2312的单位面积容量大于另一第二负极活性物质层2313的单位面积活性物质容量。
在一些实施例中，相邻的两个第一负极活性物质层2312中的一个第一负极活性物质层2312的活性材料的克容量大于另一个第一负极活性物质层2312的活性材料的克容量，所述的另一个第一负极活性物质层2312相较于所述的一个第一负极活性物质层2312更靠近所述厚度中心面B。可以理解地，在抵靠区B1，厚度方向X，距离厚度中心面B越远(距离壳体21的侧壁211越近)的第一负极活性物质层2312的克容量越大。
克容量与第一负极活性物质层2312中的活性材料有关，比如相邻的两个第一负极活性物质层2312中的较为靠近壳体21的侧壁211的第一负极活性物质 层2312的活性材料为硅的化合物，另一个第一负极活性物质的活性材料为石墨，硅的化合物的材料活性大于石墨的材料活性，以使相邻的两个第一负极活性物质层2312中较为靠近壳体21的侧壁211的一个第一负极活性物质层2312的嵌锂能力大于另一个第一负极活性物质层2312的嵌锂能力，能够进一步减小抵靠区B1受电解液挤出的影响。
在一些实施例中，相邻的两个第一负极活性物质层2312中的一个第一负极活性物质层2312的活性材料的重量与所述的一个第一负极活性物质层2312的重量的比值大于另一个第一负极活性物质层2312的活性材料的重量与所述的另一个第一负极活性物质层2312的重量的比值，所述的另一个第一负极活性物质层2312相较于所述的一个第一负极活性物质层2312更靠近于厚度中心面B。可以理解地，在抵靠区B1，厚度方向X，距离厚度中心面B越远(距离壳体21的侧壁211越近)的第一负极活性物质层2312的活性材料的重量与第一负极活性物质层2312的重量的比值越大。
在一些实施例中，通过增加相邻两个第一负极活性物质层2312中较为靠近壳体21的侧壁211的一个第一负极活性物质层2312中的活性材料，提高该第一负极活性物质层2312中的活性材料的占比，从而增大该第一负极活性物质层2312的单位面积活性物质容量，以使靠近壳体21的第一负极活性物质层2312的单位面积活性物质容量大于另一个第一负极活性物质层2312的单位面积活性物质容量。
在一些实施例中，也可以减小较为靠近壳体21的第一负极活性物质层2312中的粘接剂和导电剂的重量，以使较为靠近壳体21的第一负极活性物质层2312的重量降低，从而提高活性物质在该第一负极活性物质层2312中的占比，相当于减小了相邻两个第一负极活性物质层2312中较为靠近壳体21的一个第一负极活性物质层2312的涂布重量，不仅能够使得该第一负极活性物质层2312中的活性材料的重量与该第一负极活性物质层2312的重量的比值大于另一第二负极活性物质层2313的活性材料的重量与另一第二负极活性物质层2313的重量的比值，还能降低靠近壳体21的第一负极活性物质层2312对电解液的需求，通过更少量的电解液即可实现第一负极活性物质层2312的浸润，够减小第一负极活性物质层2312受电解液挤出的影响。
对每个第一负极活性物质层2312而言，电极组件23膨胀时，越靠近第一负极活性物质层的中心O1的位置受到的挤压力越大，电解液被挤出的程度越大。
基于此，在一些实施例中，如图9所示，第一负极活性物质层2312包括多个负极活性区段，相邻的两个负极活性区段中的一个负极活性区段的单位面积活性物质容量大于另一个负极活性区段的单位面积活性物质容量，所述的一个负极活性区段相较于所述的另一个负极活性区段更靠近第一负极活性物质层的中心O1。可以理解地，在抵靠区B1，距离第一负极活性物质层的中心O1越近的负极活性区段的单位面积活性物质容量越大。通过将第一负极活性物质层2312划分为多个负极活性区段，且越靠近第一负极活性物质层的中心O1的负极活性区段的单位面积活性物质容量越大，使得靠近第一负极活性物质层的中心O1的位置受电解液被挤出的影响较小，能够进一步有效降低因抵靠区B1与壳体21抵靠时电解液被挤出而造成析锂的风险。
在一些实施例中，相邻的两个负极活性区段中的一个负极活性区段的活性材料的克容量大于另一个负极活性区段中的活性材料的克容量，所述一个负极活性区段相较于所述另一个负极活性区段更靠近所述第一负极活性物质层的中心O1，以使较为靠近第一负极活性物质层2312的单位面积活性物质容量大于另一个第一负极活性物质层2312的单位面积活性物质容量。
在一些实施例中，相邻两个负极活性区段中的一个负极活性区段的活性材料的重量与所述一个负极活性区段的重量的比值大于另一个负极活性区段的活性材料的重量与所述另一个负极活性区段的重量的比值，所述一个负极活性区段相较于所述另一个负极活性区段更靠近第一负极活性物质层的中心O1。
在一些实施例中，通过增加相邻两个负极活性区段中靠近壳体21的一个负极活性区段中的活性材料，提高该负极活性区段中的活性材料的占比，从而增大该负极活性区段的单位面积活性物质容量，以使相邻两个负极活性区段中较为靠近第一负极活性物质层的中心O1的负极活性区段的单位面积活性物质容量大于另一个负极活性区段的单位面积活性物质容量。
在一些实施例中，也可以减小靠近第一负极活性物质层2312中心的负极活性区段的粘接剂和导电剂的重量，以使该负极活性区段的重量降低，从而提高活性物质在该第一负极活性物质层2312中的占比，相当于减小了相邻两个负极活性区段中靠近中心的一个负极活性区段的涂布重量，不仅能够使得该负极活性区 段中的活性材料的重量与该负极活性区段的重量的比值大于另一个负极活性区段的活性材料的重量与所述的另一负极活性区段的重量的比值，还能降低靠近第一负极活性物质层的中心O1的负极活性区段对电解液的需求，通过更少量的电解液即可实现该负极活性区段的浸润，够减小第一负极活性物质层2312受电解液挤出的影响。
负极活性区段可以有多种形状，各个负极活性区段的形状可以相同也可以不同。
在一些实施例中，如图10、图11所示，每个负极活性区段呈条状，各个负极活性区段沿所述卷绕轴线的方向排列。负极活性区段的数量为奇数。
如图10所示，负极活性区段的数量为七个。沿卷绕轴线方向Z依次为第一负极活性区段2312a、第二负极活性区段2312b、第三负极活性区段2312c、第四负极活性区段2312d、第五负极活性区段2312e、第六负极活性区段2312f和第七负极活性区段2312g。在卷绕轴线方向Z上，第四负极活性区段2312d的中心面与第一负极活性物质层的中心面O2重合并经过第一负极活性物质层的中心O1，第一负极活性区段2312a和第七负极活性区段2312g关于第一负极活性物质层的中心面O2对称，第二负极活性区段2312b和第六负极活性区段2312f关于第一负极活性物质层的中心面O2对称，第三负极活性区段2312c和第五负极活性区段2312e关于第一负极活性物质层的中心面O2对称。
其中，第四负极活性区段2312d的单位面积活性物质容量大于第三负极活性区段2312c的单位面积活性物质容量，第三负极活性区段2312c的单位面积活性物质容量大于第二负极活性区段2312b的单位面积活性物质容量，第二负极活性区段2312b的单位面积活性物质容量大于第一负极活性区段2312a的单位面积活性物质容量；第四负极活性区段2312d的单位面积活性物质容量大于第五负极活性区段2312e的单位面积活性物质容量，第五负极活性区段2312e的单位面积活性物质容量大于第六负极活性区段2312f的单位面积活性物质容量，第六负极活性区段2312f的单位面积活性物质容量大于第七负极活性区段2312g的单位面积活性物质容量。
在一些实施例中，如图11所示，负极活性区段的数量为三个，沿卷绕轴线方向Z依次为第一负极活性区段2312a、第二负极活性区段2312b和第三负极活性区段2312c。在卷绕轴线方向Z上，第二负极活性区段2312b的中心面与第一负极活性物质层的中心面O2重合并经过第一负极活性物质层的中心O1，第一 负极活性区段2312a和第三负极活性区段2312c关于第一负极活性物质层的中心面O2对称。
第二负极活性区段2312b的单位面积活性物质容量大于第一负极活性区段2312a的单位面积活性物质容量，第二负极活性区段2312b的单位面积活性物质容量大于第三负极活性区段2312c的单位面积活性物质容量。第一负极活性区段2312a的单位面积活性物质容量与第三负极活性区段2312c的单位面积活性物质容量相同。
对称，是指关于第一负极活性物质层的中心面O2对称的两个负极活性区段的面积、单位面积活性物质容量均相同。
当负极活性区段呈条状并沿卷绕轴线方向Z排列，则各个负极活性区段相对的第一负极活性物质层的中心O1的距离可以理解为是相对第一负极活性物质层的中心面O2的距离。
在一些实施例中，如图12-图14所示，所述的多个负极活性区段包括中央负极活性区段2312h和至少一个外围负极活性区段，每个外围负极活性区段呈环状且围绕中央负极活性区段2312h，中央负极活性区段2312h和所述的至少一个外围负极活性区段以第一负极活性物质层的中心O1呈辐射状分布。每个负极活性区段环布于第一负极活性物质层的中心O1，则沿任意方向，相邻的两个负极活性区段中靠近中心的一个的负极活性区段的单位面积活性物质容量均大于另一个负极活性区段的单位面积活性物质的容量。
中央负极活性区段2312h的单位面积活性物质容量大于外围负极活性区段的单位面积活性物质容量。
在一些实施例中，如图12所示，中央负极活性区段2312h为矩形，外围负极活性区段的数量为一个，定义为第一外围负极活性区段2312i，外围负极活性区段的内轮廓呈矩形并与中央负极活性区段2312h的外轮廓重合，外围负极活性区段的外轮廓呈矩形。中央负极活性区段2312h的中心即为第一负极活性物质层的中心O1。
在一些实施例中，如图13所示，外围负极活性区段的数量为三个，分别为第一外围负极活性区段2312i、第二外围负极活性区段2312j和第三外围负极活性区段2312k。第一外围负极活性区段2312i环布于中央负极活性区段2312h，第一外围负极活性区段2312i的内轮廓与中央负极活性区段2312h的外轮廓重合，第二外围负极活性区段2312j环布于第一外围负极活性区段2312i，第二外围负极 活性区段2312j的内轮廓与第一外围负极活性区段2312i的外轮廓重合，第三外围负极活性区段2312k环布于第二外围负极活性区段2312j，第三外围负极活性区段2312k的内轮廓与第二外围负极活性区段2312j的外轮廓重合，第三外围负极活性区段2312k的外轮廓呈矩形。中央负极活性区段2312h的中心即为第一负极活性物质层的中心O1。中央负极活性区段2312h的外轮廓为矩形，第一外围负极活性区段2312i的内轮廓和外轮廓均为矩形，第二外围负极活性区段2312j的内轮廓和外轮廓均为矩形，第三外围负极活性区段2312k的内轮廓和外轮廓均为矩形。
在一些实施例中，如图14所示，中央负极活性区段2312h的外轮廓为椭圆形。第一外围负极活性区段2312i的内轮廓和外轮廓均为椭圆形；第二外围负极活性区段2312j的内轮廓和外轮廓均为椭圆形；第三外围负极活性区段2312k的内轮廓为椭圆形，第三外围负极活性物质层的外轮廓为矩形。中央负极活性区段2312h呈椭圆形，能够更加贴近抵靠区B1与壳体21抵靠时第一负极活性物质层2312的膨胀形变状态，有利于降低因抵靠区B1与壳体21抵靠时电解液被挤出而造成析锂的风险。
在一些实施例中，第一负极活性物质层2312的活性材料的粒径小于第二负极活性物质层2313的活性材料的粒径。在充放电的过程中，锂离子在第一负极活性物质层2312中更容易扩散，在第一负极活性物质层2312中分布的更为均匀，不易在第一负极活性物质层2312聚集，从而降低析锂的风险，且还能提高第一负极活性物质层2312的快充性能。
在一些实施例中，每个第一负极活性物质层2312中越靠近第一负极活性物质层的中心O1的负极活性区段中的活性材料的粒径越小。
在一些实施例中，示例性地，请继续参见图14，第三外围负极活性区段2312k是第一负极活性物质层2312中活性材料粒径的最大的区域，第三外围负极活性区段2312k中的活性材料的粒径为D，则第二外围负极活性区段2312j中的活性材料的粒径、第一外围负极活性区段2312i中的活性材料的粒径和中央负极活性区段2312h中的活性材料的粒径分别为0.8D、0.6D和0.4D。在电极组件23膨胀时，中央负极活性区段2312h膨胀最严重，中央负极活性区段2312h中的活性材料的粒径最小，能够有效提高锂离子在中央负极活性区段2312h的扩散能力，不易在中央负极活性区段2312h聚集，从而降低析锂的风险。
在一些实施例中，如图15所示，沿电极组件23的厚度方向X，负极集流体2311两个表面上的第一负极活性物质层2312的单位面积活性物质容量不相 同。负极集流体2311距离厚度中心面B较近的一侧的表面上的第一负极活性物质层2312的单位面积活性物质容量小于负极集流体2311距离厚度中心面B较远的一侧的表面上的第一负极活性物质层2312的单位面积活性物质容量。即图15中，在抵靠区B1中，负极集流体2311的内侧的内层负极活性物质层2312m的单位面积活性物质容量小于外层负极活性物质层2312n的单位面积活性物质容量。负极集流体2311的内侧和外侧是相对厚度中心面B而言的，距离厚度中心面B较近的一侧为内侧，距离厚度中心面B较远的一侧为外侧。
在一些实施例中，也可以通过对正极片232的改进以降低因抵靠区B1与壳体21抵靠时电解液被挤出而造成析锂的风险。
在一些实施例中，如图16所示，第一正极活性物质层2322的单位面积活性物质容量小于第二正极活性物质层2323的单位面积活性物质容量。
在一些实施例中，沿厚度方向X，任意一层正极集流体2321的两个表面的第二正极活性物质层2323的单位面积活性物质容量相同，则第二正极活性物质层2323的单位面积活性物质容量可以代表对应层的负极集流体2311两个表面上的第二正极活性物质层2323的单位面积活性物质容量。
当不与壳体21抵靠的非抵靠区B2的第二正极活性物质层2323的单位面积活性物质容量满足设计要求时，即非抵靠区B2的第二正极活性物质层2323的单位面积活性物质容量达到第二预设值使得非抵靠区B2的第二负极活性物质层2313不易出现析锂。当位于抵靠区B1的第一正极活性物质层2322的单位面积活性物质容量小于位于非抵靠区B2的第二正极活性物质层2323的单位面积活性物质容量，即第一正极活性物质层2322的单位面积活性物质容量小于第二预设值，相当于降低了第一正极活性物质层2322的单位面积活性物质容量，则第一负极活性物质层2312能够接受从第一正极活性物质层2322脱出的锂离子，抵靠区B1的第一负极出现析锂的可能性较小，从而能够有效降低因抵靠区B1与壳体21抵靠时电解液被挤出而造成析锂的风险。
需要说明的是，第一正极活性物质层2322的单位面积活性物质容量，是指第一正极活性物质层2322的活性物质容量与第一正极活性物质层2322的总面积的比值，第二正极活性物质层2323的单位面积活性物质容量，是指第二正极活性物质层2323的活性物质容量与第二正极活性物质层2323的总面积的比值。进一步解释为，第一正极活性物质层2322的活性物质容量为E1，第一正极活性物质层2322的面积为G1，则第一正极活性物质层2322的单位面积容量 EG1＝E1/G1。第二正极活性物质层2323的活性物质容量为E2，第二正极活性物质层2323的面积为G2，则第二正极活性物质层2323的单位面积容量EG2＝E2/G2。
影响第一正极活性物质层2322的单位面积活性物质容量和第二正极活性物质层2323的单位面积活性物质容量的因素有很多，因此，可以通过较多的方式实现第一正极活性物质层2322的单位面积容量小于第二正极活性物质层2323的单位面积活性物质容量。
在一些实施例中，第一正极活性物质层2322的活性材料的克容量小于第二正极活性物质层2323的活性材料的克容量。
通过减小抵靠区B1的第一正极活性物质层2322的活性材料的克容量，可减小抵靠区B1的第一正极活性物质层2322的单位面积活性物质容量，以使抵靠区B1的第一正极活性物质层2322的单位面积容量小于非抵靠区B2的第二正极活性物质的单位面积容量，能够有效降低因抵靠区B1与壳体21抵靠时电解液被挤出而造成析锂的风险。
克容量与第一正极活性物质层2322中的活性材料和第二正极活性物质层2323中的活性材料有关，比如，第一正极活性物质层2322的活性材料与第二正极活性物质层2323的活性材料不同，第一正极活性物质层2322的活性材料为磷酸铁锂，第二正极活性物质层2323的活性材料为三元锂。磷酸铁锂的材料活性小于三元锂的材料活性，以使第一正极活性物质层2322的脱锂能力小于第二正极活性物质层2323的脱锂能力，能够进一步减小抵靠区B1受电解液挤出的影响。
在一些实施例中，第一正极活性物质层2322的活性材料的重量与第一正极活性物质层2322的重量的比值小于第二正极活性物质层2323的活性材料的重量与第二正极活性物质层2323的重量的比值。第一正极活性物质层2322和第二正极活性物质层2323中均包括活性材料、粘接剂和导电剂，通过降低第一正极活性物质层2322中的活性材料，降低第一正极活性物质层2322中的活性材料的占比，从而降低第一正极活性物质层2322的单位面积活性物质容量，以使第一正极活性物质层2322的单位面积活性物质容量小于第二正极活性物质层2323的单位面积活性物质容量。
在抵靠区B1，沿厚度方向X，越靠近壳体21的位置与壳体21挤压程度越严重。
基于此，如图17所示，在一些实施例中，沿厚度方向X，相邻的两个第一正极活性物质层2322中的一个第一正极活性物质层2322的单位面积活性物质容量小于另一个第一正极活性物质层2322的单位面积活性物质容量，所述的另一个第一正极活性物质层2322相较于所述的一个第一正极活性物质层2322更靠近所述厚度中心面B。可以理解地，在抵靠区B1，沿厚度方向X，距离厚度中心面B越远(距离壳体21的侧壁211越近)的第一正极活性物质层2322的单位面积活性物质容量越小，能够进一步有效降低因抵靠区B1与壳体21抵靠时电解液被挤出而造成析锂的风险。
可以通过较多的方式实现相邻的两个第一正极活性物质层2322中较为靠近壳体21的一个第一正极活性物质层2322的单位面积容量小于另一第二正极活性物质层2323的单位面积活性物质容量。
在一些实施例中，相邻的两个第一正极活性物质层2322中的一个的第一正极活性物质层2322的活性材料的克容量小于另一个第一正极活性物质层2322的活性材料的克容量，所述的另一个第一正极活性物质层2322相较于所述额一个第一正极活性物质层2322更靠近厚度中心面B。可以理解地，在抵靠区B1，厚度方向X，距离厚度中心面B越远(距离壳体21的侧壁211越近)的第一正极活性物质层2322的克容量越小。
克容量与第一正极活性物质层2322中的活性材料有关，比如，相邻的两个第一正极活性物质层2322的活性材料不同，靠近壳体21的第一正极活性物质层2322的活性材料为磷酸铁锂，另一个第一正极活性物质的活性材料为三元锂，以使相邻的两个第一正极活性物质层2322中靠近壳体21的一个第一正极活性物质层2322的脱锂能力小于另一个第一正极活性物质层2322的脱锂能力，能够进一步减小抵靠区B1受电解液挤出的影响。
在一些实施例中，相邻的两个第一正极活性物质层2322中的一个第一正极活性物质层2322的活性材料的重量与所述的一个第一正极活性物质层2322的重量的比值小于另一个第一正极活性物质层2322的活性材料的重量与所述的另一个第一正极活性物质层2322的重量的比值，所述的另一个第一正极活性物质层2322相较于所述的一个第一正极活性物质层2322更靠近厚度中心面B。可以理解地，在抵靠区B1，厚度方向X，距离厚度中心面B越远(距离壳体21的侧壁211越近)的第一正极活性物质层2322的活性材料的重量与第一正极活性物质层2322的重量的比值越小。
通过降低相邻两个第一正极活性物质层2322中靠近壳体21的一个第一正极活性物质层2322中的活性材料，降低该第一正极活性物质层2322中的活性材料的占比，从而减小该第一正极活性物质层2322的单位面积活性物质容量，以使靠近壳体21的第一正极活性物质层2322的单位面积活性物质容量小于另一个第一正极活性物质层2322的单位面积活性物质容量。
对每个第一正极活性物质层2322而言，电极组件23膨胀时，越靠近第一正极活性物质层的中心O3的位置受到的挤压力越大，电解液被挤出的程度越大。
基于此，在一些实施例中，如图18所示，第一正极活性物质层2322包括多个正极活性区段，相邻的两个正极活性区段中的一个正极活性区段的单位面积活性物质容量小于另一个正极活性区段的单位面积活性物质容量，所述的一个正极活性区段相较于所述的另一个正极活性区段更靠近第一正极活性物质层的中心O3。可以理解地，在抵靠区B1，距离第一正极活性物质层的中心O3越近的正极活性区段的单位面积活性物质容量越小。通过将第一正极活性物质层2322划分为多个负极活性区段，且越靠近第一正极活性物质层的中心O3的负极活性区段的单位面积活性物质容量越小，从而降低靠近第一正极活性物质层2322中心的位置的正极活性区段的脱锂能力，使得靠近第一负极活性物质层2312中心的位置受电解液被挤出的影响较小，能够进一步有效降低因抵靠区B1与壳体21抵靠时电解液被挤出而造成析锂的风险。
在一些实施例中，相邻的两个正极活性区段中的一个正极活性区段的活性材料的克容量小于另一个正极活性区段的活性材料的克容量，所述的一个正极活性区段相较于所述的另一个正极活性区段更靠近第一正极活性物质层的中心O3，以使更加靠近第一正极活性物质层的中心O3的正极活性区段的单位面积活性物质容量更小。
在一些实施例中，相邻两个正极活性区段中的一个正极活性区段的活性材料的重量与所述的一个正极活性区段的重量的比值小于另一个正极活性区段的活性材料的重量与所述的另一个正极活性区段的重量的比值，所述的一个正极活性区段相较于所述的另一个正极活性区段更靠近所述第一正极活性物质层的中心O3，以使更加靠近第一正极活性物质层的中心O3的正极活性区段的单位面积活性物质容量更小。通过降低相邻两个正极活性区段中较为靠近第一正极活性物质层的中心O3的一个正极活性区段中的活性材料，降低该正极活性区段中的活性 材料的占比，从而降低该正极活性区段的单位面积活性物质容量，以使相邻的两个正极活性区段中较为靠近第一正极活性物质层的中心O3的正极活性区段的单位面积活性物质容量小于另一个正极活性区段的单位面积活性物质容量。
正极活性区段可以有多种形状，各个负极活性区段的形状可以相同也可以不同。
在一些实施例中，如图19、图20所示，每个正极活性区段呈条状，各个正极活性区段沿所述卷绕轴线的方向排列。正极活性区段呈条状，负极活性物质层涂覆方便。负极活性区段的数量为奇数。
如图19所示，正极活性区段的数量为七个。沿卷绕轴线方向Z依次为第一正极活性区段2322a、第二正极活性区段2322b、第三正极活性区段2322c、第四正极活性区段2322d、第五正极活性区段2322e、第六正极活性区段2322f和第七正极活性区段2322g。在卷绕轴线方向Z上，第四正极活性区段2322d的中心面与第一正极活性物质层的中心面O4重合并经过第一正极活性物质层的中心O3，第一正极活性区段2322a和第七正极活性区段2322g关于第一正极活性物质层的中心面O4对称，第二正极活性区段2322b和第六正极活性区段2322f关于第一正极活性物质层的中心面O4对称，第三正极活性区段2322c和第五正极活性区段2322e关于第一正极活性物质层的中心面O4对称。
第四正极活性区段2322d的单位面积活性物质容量小于第三正极活性区段2322c的单位面积活性物质容量，第三正极活性区段2322c的单位面积活性物质容量小于第二负极活性区段2312b的单位面积活性物质容量，第二正极活性区段2322b的单位面积活性物质容量小于第一正极活性区段2322a的单位面积活性物质容量；第四正极活性区段2322d的单位面积活性物质容量小于第五正极活性区段2322e的单位面积活性物质容量，第五正极活性区段2322e的单位面积活性物质容量小于第六正极活性区段2322f的单位面积活性物质容量，第六正极活性区段2322f的单位面积活性物质容量小于第七正极活性区段2322g的单位面积活性物质容量。
在一些实施例中，如图20所示，正极活性区段的数量为三个，沿卷绕轴线方向Z依次为第一正极活性区段2322a、第二正极活性区段2322b和第三正极活性区段2322c。在卷绕轴线方向Z傻瓜，第二正极活性区段2322b的中心面与第一正极活性物质层的中心面O4重合并经过第一正极活性物质层的中心O3，第 一正极活性区段2322a和第三正极活性区段2322c关于第一正极活性物质层的中心面O4对称。
第二正极活性区段2322b的单位面积活性物质容量小于第一正极活性区段2322a的单位面积活性物质容量，第二正极活性区段2322b的单位面积活性物质容量小于第三正极活性区段2322c的单位面积活性物质容量。第一正极活性区段2322a的单位面积活性物质容量与第三正极活性区段2322c的单位面积活性物质容量相同。
当正极活性区段呈条状并沿卷绕轴线方向Z排列，则各个正极活性区段相对的第一正极活性物质层的中心O3的距离可以理解为是相对第一正极活性物质层的中心面O4的距离。
在一些实施例中，如图21-图23所示，所述的多个正极活性区段包括中央正极活性区段2322h和至少一个外围正极活性区段，每个外围正极活性区段呈环状且围绕中央正极活性区段2322h，中央正极活性区段2322h和所述的至少一个外围正极活性区段以第一正极活性物质层的中心O3呈辐射状分布。
中央正极活性区段2322h的单位面积活性物质容量小于外围正极活性区段的单位面积活性物质容量。
在一些实施例中，如图21所示，中央正极活性区段2322h为矩形，外围正极活性区段的数量为一个，定义为第一外围正极活性区段2322i，外围正极活性区段的内轮廓呈矩形并与中央正极活性区段2322h的外轮廓重合，外围正极活性区段的外轮廓呈矩形。中央正极活性区段2322h的中心即为第一正极活性物质层的中心O3。
在一些实施例中，如图22所示，外围负极活性区段的数量为三个，分别为第一外围正极活性区段2322i、第二外围正极活性区段2322j和第三外围正极活性区段2322k。第一外围正极活性区段2322i环布于中央正极活性区段2322h，第一外围正极活性区段2322i的内轮廓与中央正极活性区段2322h的外轮廓重合，第二外围正极活性区段2322j环布于第一外围正极活性区段2322i，第二外围正极活性区段2322j的内轮廓与第一外围正极活性区段2322i的外轮廓重合，第三外围正极活性区段2322k环布于第二外围正极活性区段2322j，第三外围正极活性区段2322k的内轮廓与第二外围正极活性区段2322j的外轮廓重合，第三外围正极活性区段2322k的外轮廓呈矩形。中央正极活性区段2322h的中心即为第一正极活性物质层的中心O3。中央正极活性区段2322h的外轮廓为矩形，第一外围正极活性 区段2322i的内轮廓和外轮廓均为矩形，第二外围正极活性区段2322j的内轮廓和外轮廓均为矩形，第三外围正极活性区段2322k的内轮廓和外轮廓均为矩形。
在一些实施例中，如图23所示，中央正极活性区段2322h的外轮廓为椭圆形，能够更加贴近抵靠区B1与壳体21抵靠时第一正极活性物质层2322的膨胀形变状态，有利于降低因抵靠区B1与壳体21抵靠时电解液被挤出而造成析锂的风险。
在一些实施例中，第一正极活性物质层2322的活性材料的粒径大于第二正极活性物质层2323的活性材料的粒径。在充放电的过程中，锂离子在第一正极活性物质层中扩散速率低，锂离子从第一正极活性物质层中脱出的速率也会降低，能够降低从第一正极活性物质层脱出的锂离子在第一负极活性物质层聚集的风险，使得第一负极活性物质层不容易析锂。
在一些实施例中，每个第一正极活性物质层2322中越靠近第一正极活性物质层的中心O3的正极活性区段中的活性材料的粒径越大。
示例性地，请继续参见图23，中央正极活性区段2322h中为第一正极活性物质层2322中的活性材料粒径最大的区段，中央正极活性区段2322h中的活性材料的粒径为K，则第一外围正极活性区段2322i中的活性材料的粒径、第二外围正极活性区段2322j中的活性材料的粒径和第三外围正极活性区段2322k中的活性材料的粒径分别为0.8K、0.6K和0.4K。
在一些实施例中，如图24所示，沿电极组件23的厚度方向X，正极集流体2321两个表面上的第一正极活性物质层2322的单位面积活性物质容量不相同。正极集流体2321距离厚度中心面B较近的一侧的表面上的第一正极活性物质层2322的单位面积活性物质容量小于正极集流体2321距离厚度中心面B较远的一侧的表面上的第一正极活性物质层2322的单位面积活性物质容量，即图中24中，抵靠区B1中，正极集流体2321的内层正极活性物质层2322m的单位面积活性物质容量大于正极集流体2321的外层正极活性物质层2322n的单位面积活性物质容量。正极集流体2321的内侧和外侧是相对厚度中心面B而言的，距离厚度中心面B较近的一侧为内侧，距离厚度中心面B较远的一侧为外侧。
在一些实施例中，如图25所示，可以既对负极片231改进也对正极片232改进，以使第一负极活性物质层2312的单位面积活性物质容量大于第二负极活性物质层2313的单位面积活性物质容量；和第一正极活性物质层2322的单位面积活性物质容量小于第二正极活性物质层2323的单位面积活性物质容量。
如图26所示，本申请实施例还提供一种电极组件23的制造方法，包括：
S100：提供正极片232和负极片231；
S200：将负极片231和正极片232层叠设置并绕卷绕轴线卷绕形成卷绕结构，以使电极组件23包括位于其厚度中心面B两侧的用于与壳体21抵靠的抵靠区B1和不与壳体21抵靠的非抵靠区B2，厚度中心面B垂直于电极组件23的厚度方向X且经过卷绕轴线。
其中，负极片231包括位于抵靠区B1且沿厚度方向X层叠布置的多个第一负极活性物质层2312和位于非抵靠区B2且沿厚度方向X层叠布置的多个第二负极活性物质层2313；正极片232包括位于抵靠区B1且沿厚度方向X层叠布置的多个第一正极活性物质层2322和位于非抵靠区B2且沿厚度方向X层叠布置的多个第二正极活性物质层2323；第一负极活性物质层2312的单位面积活性物质容量大于第二负极活性物质层2313的单位面积活性物质容量；和/或，第一正极活性物质层2322的单位面积活性物质容量小于第二正极活性物质层2323的单位面积活性物质容量。
需要说明的是，通过上述电极组件23的制造方法制造处的电极组件23的相关结构，可参见上述各实施例提供的电极组件23。
如图27所示，本申请实施例还提供一种电极组件的制造设备400，包括：提供装置410，用于提供正极片232和负极片231；组装装置420，用于将正极片232和负极片231层叠设置并卷绕形成卷绕结构，以使电极组件23包括位于其厚度中心面B两侧的用于与壳体21抵靠的抵靠区B1和不与壳体21抵靠的非抵靠区B2，厚度中心面B垂直于电极组件23的厚度方向X且经过卷绕轴线；其中，负极片231包括位于抵靠区B1且沿厚度方向X层叠布置的多个第一负极活性物质层2312和位于非抵靠区B2且沿所述厚度方向X层叠布置的多个第二负极活性物质层2313；正极片232包括位于抵靠区B1且沿厚度方向X层叠布置的多个第一正极活性物质层2322和位于非抵靠区B2且沿所述厚度方向X层叠布置的多个第二正极活性物质层2323；第一负极活性物质层2312的单位面积活性物质容量大于第二负极活性物质层2313的单位面积活性物质容量；和/或，第一正极活性物质层2322的单位面积活性物质容量小于第二正极活性物质层2323的单位面积活性物质容量。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的部件。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. 一种电极组件，用于容纳于壳体，其中，所述电极组件包括正极片和负极片，所述正极片和所述负极片层叠设置并绕卷绕轴线卷绕；
    所述电极组件包括位于其厚度中心面两侧的用于与所述壳体抵靠的抵靠区和不与所述壳体抵靠的非抵靠区，所述厚度中心面垂直于所述电极组件的厚度方向且经过所述卷绕轴线；
    所述负极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一负极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二负极活性物质层；所述正极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一正极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二正极活性物质层；
    所述第一负极活性物质层的单位面积活性物质容量大于所述第二负极活性物质层的单位面积活性物质容量；和/或，所述第一正极活性物质层的单位面积活性物质容量小于所述第二正极活性物质层的单位面积活性物质容量。
  2. 根据权利要求1所述的电极组件，其中，所述第一负极活性物质层的活性材料的克容量大于所述第二负极活性物质层的活性材料的克容量；和/或，所述第一正极活性物质层的活性材料的克容量小于所述第二正极活性物质层的活性材料的克容量。
  3. 根据权利要求1或2所述的电极组件，其中，所述第一负极活性物质层的活性材料的重量与所述第一负极活性物质层的重量的比值大于所述第二负极活性物质层的活性材料的重量与所述第二负极活性物质层的重量的比值；和/或，所述第一正极活性物质层的活性材料的重量与所述第一正极活性物质层的重量的比值小于所述第二正极活性物质层的活性材料的重量与所述第二正极活性物质层的重量的比值。
  4. 根据权利要求1-3任一项所述的电极组件，其中，相邻的两个第一负极活性物质层中的一个第一负极活性物质层的单位面积活性物质容量大于另一个第一负极活性物质层的单位面积活性物质容量，所述另一个第一负极活性物质层相较于所述一个第一负极活性物质层更靠近所述厚度中心面；和/或，相邻的两个第一正极活性物质层中的一个第一正极活性物质层的单位面积活性物质容量小于另一个第一正极活性物质层的单位面积活性物质容量，所述另一个第一正极活性物质层相较于所述一个第一正极活性物质层更靠近所述厚度中心面。
  5. 根据权利要求4所述的电极组件，其中，相邻的两个第一负极活性物质层中的一个第一负极活性物质层的活性材料的克容量大于另一个第一负极活性物质层的活性材料的克容量，所述另一个第一负极活性物质层相较于所述一个第一负极活性物质层更靠近所述厚度中心面；和/或，相邻的两个第一正极活性物质层中的一个的第一正极活性物质层的活性材料的克容量小于另一个第一正极活性物质层的活性材料的克容量，所述另一个第一正极活性物质层相较于所述一个第一正极活性物质层更靠近所述厚度中心面。
  6. 根据权利要求4或5所述的电极组件，其中，相邻的两个第一负极活性物质层中的一个第一负极活性物质层的活性材料的重量与所述一个第一负极活性物质层的重量的比值大于另一个第一负极活性物质层的活性材料的重量与所述另一个第一负极活性物质层的重量的比值，所述另一个第一负极活性物质层相较于所述一个第一负极活性物质层更靠近于所述厚度中心面；和/或，相邻的两个第一正极活性物质层中的一个第一正极活性 物质层的活性材料的重量与所述一个第一正极活性物质层的重量的比值小于另一个第一正极活性物质层的活性材料的重量与所述另一个第一正极活性物质层的重量的比值，所述另一个第一正极活性物质层相较于所述一个第一正极活性物质层更靠近所述厚度中心面。
  7. 根据权利要求1-6任一项所述的电极组件，其中，所述第一负极活性物质层包括多个负极活性区段，所述第一正极活性物质层均包括多个正极活性区段；
    相邻的两个负极活性区段中的一个负极活性区段的单位面积活性物质容量大于另一个负极活性区段的单位面积活性物质容量，所述一个负极活性区段相较于所述另一个负极活性区段更靠近所述第一负极活性物质层的中心；和/或，相邻的两个正极活性区段中的一个区段的单位面积活性物质容量小于另一个正极活性区段的单位面积活性物质容量，所述一个正极活性区段相较于所述另一个正极活性区段更靠近所述第一正极活性物质层的中心。
  8. 根据权利要求7所述的电极组件，其中，相邻的两个负极活性区段中的一个负极活性区段的活性材料的克容量大于另一个负极活性区段中的活性材料的克容量，所述一个负极活性区段相较于所述另一个负极活性区段更靠近所述第一负极活性物质层的中心；和/或，相邻的两个正极活性区段中的一个正极活性区段的活性材料的克容量小于另一个正极活性区段的活性材料的克容量，所述一个正极活性区段相较于所述另一个正极活性区段更靠近所述第一正极活性物质层的中心。
  9. 根据权利要求7或8所述的电极组件，其中，相邻两个负极活性区段中的一个负极活性区段的活性材料的重量与所述一个负极活性区段的重量的比值大于另一个负极活性区段的活性材料的重量与所述另一个负极活性区段的重量的比值，所述一个负极活性区段相较于所述另一个负极活性区段更靠近所述第一负极活性物质层的中心；和/或，相邻两个正极活性区段中的一个正极活性区段的活性材料的重量与所述一个正极活性区段的重量的比值小于另一个正极活性区段的活性材料的重量与所述另一个正极活性区段的重量的比值，所述一个正极活性区段相较于所述另一个正极活性区段更靠近所述第一正极活性物质层的中心。
  10. 根据权利要求7-9任一项所述的电极组件，其中，每个负极活性区段呈条状，所述多个负极活性区段沿所述卷绕轴线的方向排列；和/或，每个正极活性区段呈条状，所述多个正极活性区段沿所述卷绕轴线的方向排列。
  11. 根据权利要求7-9任一项所述的电极组件，其中，所述多个负极活性区段包括中央负极活性区段和至少一个外围负极活性区段，每个外围负极活性区段呈环状且围绕所述中央负极活性区段，所述中央负极活性区段和所述至少一个外围负极活性区段以所述第一负极活性物质层的中心呈辐射状分布；和/或，所述多个正极活性区段包括中央正极活性区段和至少一个外围正极活性区段，每个外围正极活性区段呈环状且围绕所述中央正极活性区段，所述中央正极活性区段和所述至少一个外围正极活性区段以所述第一正极活性物质层的中心呈辐射状分布。
  12. 根据权利要求11所述的电极组件，其中，所述中央负极活性区段和/或所述中央正极活性区段呈椭圆形。
  13. 一种电池单体，其中，包括：
    壳体；
    根据权利要求1-12任一项所述的电极组件，容纳于所述壳体内，所述抵靠区用于与所述壳体抵靠，所述非抵靠区用于不与所述壳体抵靠。
  14. 根据权利要求13所述的电池单体，其中，所述电池单体包括两个所述电极组件，两个所述电极组件沿所述厚度方向并排布置，两个所述电极组件的所述抵靠区相背离设置。
  15. 一种电池，其中，包括根据权利要求13或14所述的电池单体。
  16. 一种用电设备，其中，包括根据权利要求13或14所述的电池单体。
  17. 一种电极组件的制造方法，其中，包括：
    提供正极片和负极片；
    将所述负极片和所述正极片层叠设置并绕卷绕轴线卷绕形成卷绕结构，以使所述电极组件包括位于其厚度中心面两侧的用于与壳体抵靠的抵靠区和不与所述壳体抵靠的非抵靠区，所述厚度中心面垂直于所述电极组件的厚度方向且经过所述卷绕轴线；
    其中，所述负极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一负极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二负极活性物质层；所述正极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一正极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二正极活性物质层；
    所述第一负极活性物质层的单位面积活性物质容量大于所述第二负极活性物质层的单位面积活性物质容量；和/或，所述第一正极活性物质层的单位面积活性物质容量小于所述第二正极活性物质层的单位面积活性物质容量。
  18. 一种电极组件的制造设备，其中，包括：
    提供装置，用于提供正极片和负极片；
    组装装置，用于将所述正极片和所述负极片层叠设置并绕卷绕轴线卷绕形成卷绕结构，以使所述电极组件包括位于其厚度中心面两侧的用于与壳体抵靠的抵靠区和不与所述壳体抵靠的非抵靠区，所述厚度中心面垂直于所述电极组件的厚度方向且经过所述卷绕轴线；
    其中，所述负极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一负极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二负极活性物质层；所述正极片包括位于所述抵靠区且沿所述厚度方向层叠布置的多个第一正极活性物质层和位于所述非抵靠区且沿所述厚度方向层叠布置的多个第二正极活性物质层；
    所述第一负极活性物质层的单位面积活性物质容量大于所述第二负极活性物质层的单位面积活性物质容量；和/或，所述第一正极活性物质层的单位面积活性物质容量小于所述第二正极活性物质层的单位面积活性物质容量。
PCT/CN2021/083417 2021-03-26 2021-03-26 电极组件、电池单体、电池及用电设备 WO2022198672A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
PCT/CN2021/083417 WO2022198672A1 (zh) 2021-03-26 2021-03-26 电极组件、电池单体、电池及用电设备
CN202180064709.6A CN116325278A (zh) 2021-03-26 2021-03-26 电极组件、电池单体、电池及用电设备
EP21809893.7A EP4089757B1 (en) 2021-03-26 2021-03-26 Electrode assembly, battery cell, battery, and electrical device
US17/543,850 US20220311054A1 (en) 2021-03-26 2021-12-07 Electrode assembly, battery cell, battery and electric apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/083417 WO2022198672A1 (zh) 2021-03-26 2021-03-26 电极组件、电池单体、电池及用电设备

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US17/543,850 Continuation US20220311054A1 (en) 2021-03-26 2021-12-07 Electrode assembly, battery cell, battery and electric apparatus

Publications (1)

Publication Number Publication Date
WO2022198672A1 true WO2022198672A1 (zh) 2022-09-29

Family

ID=83365141

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/083417 WO2022198672A1 (zh) 2021-03-26 2021-03-26 电极组件、电池单体、电池及用电设备

Country Status (4)

Country Link
US (1) US20220311054A1 (zh)
EP (1) EP4089757B1 (zh)
CN (1) CN116325278A (zh)
WO (1) WO2022198672A1 (zh)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104471777A (zh) * 2012-08-06 2015-03-25 丰田自动车株式会社 电池
JP2020170697A (ja) * 2019-04-03 2020-10-15 国立研究開発法人産業技術総合研究所 規則構造を有する高水溶性、高エネルギー密度化有機系活物質を用いた電気化学デバイス
CN111916844A (zh) * 2020-08-13 2020-11-10 东莞新能安科技有限公司 电化学装置及电子装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104471777A (zh) * 2012-08-06 2015-03-25 丰田自动车株式会社 电池
JP2020170697A (ja) * 2019-04-03 2020-10-15 国立研究開発法人産業技術総合研究所 規則構造を有する高水溶性、高エネルギー密度化有機系活物質を用いた電気化学デバイス
CN111916844A (zh) * 2020-08-13 2020-11-10 东莞新能安科技有限公司 电化学装置及电子装置

Also Published As

Publication number Publication date
US20220311054A1 (en) 2022-09-29
EP4089757B1 (en) 2024-03-13
CN116325278A (zh) 2023-06-23
EP4089757A1 (en) 2022-11-16

Similar Documents

Publication Publication Date Title
EP4109664A1 (en) Battery cell, battery, and electric device
CN217788451U (zh) 极片、电极组件、电池单体、电池及用电设备
WO2023070677A1 (zh) 电池单体、电池、用电设备、制造电池单体的方法和设备
EP4089769B1 (en) Electrode assembly, battery cell, battery, and method and device for manufacturing electrode assembly
WO2023065923A1 (zh) 电池单体、电池和用电设备
US20230238540A1 (en) Electrode assembly, battery cell, battery, and method and device for manufacturing electrode assembly
US20240222766A1 (en) Battery, electric apparatus, and method and apparatus for manufacturing battery
US20240088449A1 (en) Winding type electrode assembly, battery cell, battery and power consumption device
WO2023155555A1 (zh) 电池单体、电池和用电设备
WO2023173429A1 (zh) 电池单体及其制造方法和制造设备、电池、用电设备
WO2022198672A1 (zh) 电极组件、电池单体、电池及用电设备
EP4199203A1 (en) Pressure relief apparatus, battery cell, battery and electrical device
WO2022160296A1 (zh) 电池单体、电池、用电设备、电池单体的制造方法及设备
CN218414630U (zh) 极片、电极组件、电池单体、电池及用电装置
WO2023159487A1 (zh) 电池、用电设备、制备电池的方法和设备
WO2023173428A1 (zh) 电池单体及其制造方法和制造设备、电池、用电设备
WO2024044883A1 (zh) 电极组件、电池单体、电池及用电装置
EP4258441A1 (en) Battery, electric device, and battery preparation method and device
WO2023065366A1 (zh) 电池、用电设备、制备电池单体的方法和设备
WO2023092338A1 (zh) 电池单体、电池、用电装置、制备电池单体的方法和装置
EP4328991A1 (en) Electrode assembly, battery cell, battery, and electric apparatus
WO2023070523A1 (zh) 电池单体、电池、用电设备、制造电池单体的方法和设备
EP4376194A1 (en) Shell, cell, battery, and electrical device
WO2023220887A1 (zh) 端盖、电池单体、电池及用电设备
WO2024040534A1 (zh) 电池单体的壳体、电池单体、电池和用电设备

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2021809893

Country of ref document: EP

Effective date: 20211129

NENP Non-entry into the national phase

Ref country code: DE