WO2022165850A1 - 电池 - Google Patents

电池 Download PDF

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Publication number
WO2022165850A1
WO2022165850A1 PCT/CN2021/076082 CN2021076082W WO2022165850A1 WO 2022165850 A1 WO2022165850 A1 WO 2022165850A1 CN 2021076082 W CN2021076082 W CN 2021076082W WO 2022165850 A1 WO2022165850 A1 WO 2022165850A1
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WO
WIPO (PCT)
Prior art keywords
distance
battery
active material
region
material layer
Prior art date
Application number
PCT/CN2021/076082
Other languages
English (en)
French (fr)
Inventor
肖良针
曾巧
Original Assignee
宁德新能源科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 宁德新能源科技有限公司 filed Critical 宁德新能源科技有限公司
Priority to EP21923860.7A priority Critical patent/EP4207350A4/en
Priority to PCT/CN2021/076082 priority patent/WO2022165850A1/zh
Publication of WO2022165850A1 publication Critical patent/WO2022165850A1/zh
Priority to US18/192,888 priority patent/US20230238655A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
    • H01M50/461—Separators, membranes or diaphragms characterised by their combination with electrodes with adhesive layers between electrodes and 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
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/538—Connection of several leads or tabs of wound or folded electrode stacks
    • 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
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/572—Means for preventing undesired use or discharge
    • H01M50/584—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries
    • H01M50/59—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries characterised by the protection means
    • H01M50/595—Tapes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to a battery.
  • Lithium-ion batteries have many advantages such as high energy density, long cycle life, high nominal voltage, low self-discharge rate, small size, and light weight, and are widely used in consumer electronics.
  • the size of the active material layer of the negative electrode sheet is usually larger than that of the positive electrode sheet.
  • the smaller the difference in size between the active material layer of the negative electrode sheet and the active material layer of the positive electrode sheet the better.
  • the size gap between the active material layer of the negative pole piece and the active material layer of the positive pole piece should be as small as possible.
  • the manufacturing process, especially the winding type battery process leads to higher requirements on the manufacturing process accuracy, otherwise, lithium deposition will occur at the edge of the battery negative pole piece, reducing the safety performance of the battery.
  • the present application provides a battery including a negative electrode active material layer, a positive electrode active material layer, and a separator between the positive electrode active material layer and the negative electrode active material layer.
  • the anode active material layer includes a first portion and a second portion connecting the first portion along the first direction.
  • the second portion includes a first surface and a first end. The first surface is connected to the first part through a first connection, and the first end is away from the first connection and is one end of the negative electrode active material layer.
  • the thickness of the second portion in a second direction perpendicular to the first direction gradually decreases along the first direction from the first connection toward the first end.
  • the positive electrode active material layer includes a third portion and a fourth portion connecting the third portion along the first direction, and the fourth portion includes a second surface and a second end.
  • the second surface is connected to the third part through a second connection point, and the second end faces away from the second connection point and is one end of the positive electrode active material layer.
  • the thickness of the fourth portion in the second direction gradually decreases from the second connection toward the second end along the first direction.
  • the first surface and the second surface are disposed at least partially opposite, and in the first direction, the first connection is located between the second connection and the second end.
  • the second end is located between the first connection and the first end.
  • the first part includes a third surface
  • the third part includes a fourth surface.
  • the third surface and the first surface are connected by a first connection point
  • the fourth surface and the second surface are connected by a second connection point; the third surface and the fourth surface are at least partially opposite to each other.
  • the third surface and the fourth surface are at least partially overlapped in the second direction; the first surface and the second surface are at least partially overlapped in the second direction; the third surface and the second surface are at least partially overlapped in the second direction at least partially coincide in direction.
  • the distance from the third surface to the fourth surface along the second direction is the first distance
  • the distance from the first surface to the second surface along the second direction is the second distance
  • the first distance is the same as The second distances are not equal.
  • the first distance is smaller than the second distance.
  • the distance from the third surface to the second surface along the second direction is a third distance, wherein the third distance is not equal to the first distance.
  • the third distance is greater than the first distance.
  • the third distance is not equal to the second distance.
  • the third distance is smaller than the second distance.
  • the first end has a first area with a distance from the second end in the first direction by the first distance, and has a distance from the second end in the first direction is the second region of the second distance, wherein the first distance and the second distance are not equal.
  • the second end when viewed along the second direction, has a plurality of protrusions.
  • the battery further includes a first layer, the first layer bonds the second end and the second surface, and continuously covers the second end and the second surface, and the first layer can block the conduction of ions.
  • the first layer also adheres to the fourth surface and covers at least part of the fourth surface.
  • the battery further includes a positive electrode current collector, the positive electrode current collector is located on the side of the positive electrode active material layer away from the first surface and the third surface, and the positive electrode current collector includes a first electrode on which the positive electrode active material layer is disposed. area and a second area located on the side of the second end away from the second connection in the first direction, the second area is not provided with the positive electrode active material layer, and the first layer also adheres to the second area and covers the first area. at least part of the second district.
  • the first layer includes a third end and a fourth end opposite to each other in the first direction, and in the first direction, the third end is located on the side of the second connection away from the second end, and the first The four ends are located on the side of the second connection away from the third end, wherein, viewed along the second direction, the distance from the second end to the third end is the fourth distance, and the distance from the second end to the fourth end is the first Five distances, and the fourth distance is not equal to the fifth distance.
  • the fourth distance is smaller than the fifth distance.
  • the fourth surface includes a third region, a discontinuity region, and a fourth region sequentially connected along the first direction, and the thickness of the portion of the positive electrode active material layer corresponding to the fourth region in the second direction is smaller than that of the positive electrode active material layer.
  • the material layer corresponds to the thickness of the third region; viewed from the second direction, the fourth region is located between the discontinuity region and the first connection, and the first layer covers the fourth region.
  • the thickness of the first layer in the second direction is greater than the height of the discontinuity zone in the second direction.
  • the portion of the blocking first layer located in the fourth region includes a fifth surface, the fifth surface is away from the fourth region, and the fifth surface includes a distance from the third region in the second direction greater than that in the second direction. Part of the distance in the direction to the third surface.
  • the first connection of the negative electrode active material layer is located between the second connection of the positive electrode active material layer and the second end of the positive electrode active material layer in the first direction, which is beneficial to maintaining battery energy Density while suppressing lithium precipitation.
  • FIG. 1 is a schematic structural diagram of a battery according to an embodiment of the present application.
  • FIG. 2 is a schematic cross-sectional view of a battery according to an embodiment of the present application.
  • FIG. 3 is a partial enlarged schematic view of the battery at the position III in FIG. 2 according to an embodiment of the present application.
  • FIG. 4 a is a partial top schematic view of the battery according to an embodiment of the present application at the position III in FIG. 2 .
  • FIG. 4b is a partial cross-sectional view of the battery according to an embodiment of the present application along the IV-IV direction in FIG. 3 .
  • FIG. 5 is a partial top schematic view of the battery according to an embodiment of the present application at the position III in FIG. 2 .
  • FIG. 6 is a partial top schematic view of the battery at the position III in FIG. 2 according to an embodiment of the present application.
  • FIG. 7 is a schematic cross-sectional view of the battery according to an embodiment of the present application at the position III in FIG. 2 .
  • FIG. 8 is a partial enlarged schematic view of the battery according to an embodiment of the present application at the position VIII in FIG. 7 .
  • FIG. 9a is a partial top schematic view of the battery according to an embodiment of the present application at the position VIII in FIG. 7 .
  • FIG. 9b is a partial cross-sectional view of the battery according to an embodiment of the present application along the IX-IX direction in FIG. 8 .
  • FIG. 10 is a partial enlarged schematic view of the battery according to an embodiment of the present application at the position VIII in FIG. 7 .
  • FIG. 11 is a partial enlarged schematic view of the battery at the position XI in FIG. 2 according to an embodiment of the present application.
  • FIG. 12 is a partial top schematic view of the battery at the position XI in FIG. 2 according to an embodiment of the present application.
  • Electrode assembly 100A main plane 100B Negative pole piece 10A Positive pole piece 30A isolation film 50 Anode active material layer 10 Anode current collector 10a District 1 10a1, 30a1 District 2 10a2, 30a2
  • first direction X first part 11 the second part 13 first surface 130 first end 131 third surface 110 first connection 101 second direction Y third direction Z
  • Positive electrode active material layer 30 Positive current collector 30a the third part 31 the fourth part 33 second surface 330 second end 331 fourth surface 310 second connection 301 central axis O-O flat part 100AA bent end 100AB bulge 333, 133 level one 60 third end 62 fourth end 64 third district 310a difference area 310b District 4 310c fifth surface 66 side 1 10aa, 30aa side 2 10ab, 30ab crease 65
  • spatially relative terms such as “on” and the like, may be used herein for convenience of description to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the figures. It will be understood that, in addition to the orientation depicted in the figures, spatially relative terms are intended to encompass different orientations of the device or apparatus in use or operation. For example, if the device in the figures is turned over, elements described as “above” or “over” other elements or features would then be oriented “below” or “beneath” the other elements or features. Thus, the exemplary term “upper” can include both an orientation of above and below.
  • an element, component, region, layer and/or section when referred to as being "between" two elements, components, regions, layers and/or sections, it can be both The only element, component, region, layer and/or section between layers and/or sections, or one or more intervening elements, components, regions, layers and/or sections may also be present.
  • first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections may not be shall be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of example embodiments.
  • the first direction X and the third direction Z are perpendicular to each other and parallel to the main plane of the electrode assembly
  • the second direction Y is perpendicular to the main plane of the electrode assembly, that is, the thickness direction of the electrode assembly.
  • the principal plane of the electrode assembly is the surface of the flat portion of the electrode assembly (100B in FIG. 1 ).
  • the thickness direction of the electrode assembly is the lamination direction of each pole piece in the flat portion of the electrode assembly.
  • the battery 100 includes an electrode assembly 100A.
  • 2 is a cross section of the battery 100 in FIG. 1 along the plane in the X direction and the Y direction.
  • the electrode assembly 100A includes a negative pole piece 10A, a positive pole piece 30A and a separator 50 between the positive pole piece 10A and the negative pole piece 30A.
  • the isolation film 50 is an electrically insulating material, and ions can pass through the isolation film 50 .
  • the negative pole piece 10A, the separator 50 and the positive pole piece 30A are stacked to form a stack, and then the stack is wound around the central axis O-O along the third direction Z for multiple times to form the electrode assembly 100A.
  • the electrode assembly 100A includes a flat portion 100AA and a plurality of bent end portions 100AB in the X direction, and the plurality of bent end portions 100AB are respectively distributed on opposite sides of the center of the flat portion 100AA of the battery 100 along the X direction, as shown in FIG. 2 . , for the left and right sides, respectively.
  • the negative pole piece 10A will be further described below.
  • the negative electrode plate 10A includes a negative electrode active material layer 10 and a negative electrode current collector 10a.
  • the anode active material layer 10 is provided on the surface of the anode current collector 10a.
  • the negative electrode current collector 10a is conductive, and includes a conductive material.
  • the conductive material may include at least one or more of conductive metals such as nickel and copper and their alloys.
  • the negative electrode current collector 10a may at least include, but is not limited to, one or two of conductive metal sheets such as nickel foil and copper foil.
  • the negative electrode current collector 10a includes a first surface 10aa and a second surface 10ab opposite to each other.
  • the first surface 10aa of the negative electrode current collector 10a includes a first region 10a1 and a second region 10a2, and the second surface 10ab of the negative electrode current collector 10a includes a first region 10a1 and a second region 10a2.
  • the first region 10a1 is a region for arranging an active material to form an active material layer
  • the second region 10a2 is a region where no active material layer is formed.
  • the first surface 10aa may include two second areas 10a2 connected to both ends of the first area 10a1 of the first surface 10aa, respectively
  • the second surface 10ab may include two second areas 10a2 and connected respectively on both ends of the first area 10a1 of the second surface 10ab.
  • the area of the first region 10a1 of the first surface 10aa may be larger than the area of the first region 10a1 of the second surface 10ab.
  • the negative electrode active material layer 10 is provided on the first region 10a1 of the first surface 10aa and the first region 10a1 of the second surface 10ab of the negative electrode current collector 10a.
  • the negative electrode active material layer 10 may include at least but not limited to graphite, soft carbon, hard carbon, graphene, mesocarbon microspheres, silicon-based materials, tin-based materials, lithium titanate or other materials that can form alloys with lithium. one or more of the metals.
  • the thickness of the negative electrode current collector 10a may be from 2 microns to 13 microns, and the thickness of the negative electrode active material layer 10 may be from 80 microns to 300 microns.
  • the ratio of the thickness of the negative electrode active material layer 10 to the thickness of the negative electrode current collector 10a may be 5 to 30, which is beneficial to reduce the proportion of the thickness of the negative electrode current collector 10a in the overall thickness of the battery, thereby facilitating the improvement of The energy density of the battery.
  • the anode active material layer 10 includes a first portion 11 and a second portion 13 connected to the first portion 11 along the first direction X.
  • the second portion 13 includes a first surface 130 and a first end 131
  • the first portion 11 includes a third surface 110 .
  • the third surface 110 is connected to the first surface 130 through the first connection 101 .
  • the first end 131 is an end of the second portion 13 away from the first connection 101
  • the first end 131 is an end of the negative electrode active material layer 10 .
  • the thickness of the second portion 13 in the second direction Y perpendicular to the first direction X decreases along the first direction X from the first connection 101 toward the first end 131 . That is, the first connection 101 is where the thickness of the second portion 13 in the second direction Y begins to decrease along the first direction X. In some embodiments, the thickness of the second portion 13 in the second direction Y decreases monotonically along the first direction X from the first connection 101 toward the first end 131 , which can be linear or curvilinear.
  • the first end 131 is located in the flat portion 100AA.
  • the anode active material layer 10 is disposed on the first region 10a1, and the second region 10a2 is disposed on the side of the first end 131 away from the first connection 101 in the first direction X.
  • the positive pole piece 30A will be further described below.
  • the positive electrode sheet 30A includes a positive electrode active material layer 30 and a positive electrode current collector 30a.
  • the positive electrode active material layer 30 is provided on the surface of the positive electrode current collector 30a.
  • the positive electrode current collector 30a is electrically conductive, and includes a conductive material.
  • the conductive material may at least include at least one or more of conductive metals such as aluminum, copper, and nickel, and their alloys.
  • the positive electrode current collector 30a may at least include but not limited to one or more of conductive metal sheets such as aluminum mesh, aluminum foil, copper mesh, copper foil, nickel foil and the like.
  • the positive electrode current collector 30a includes a first surface 30aa and a second surface 30ab opposite to each other.
  • the first surface 30aa of the positive electrode current collector 30a includes a first region 30a1 and a second region 30a2, and the second surface 30ab of the positive electrode current collector 30a includes a first region 30a1 and a second region 30a2.
  • the first region 30a1 is a region for arranging an active material to form an active material layer
  • the second region 30a2 is a region where no active material layer is formed.
  • the first surface 30aa may include two second areas 30a2 connected to both ends of the first area 30a1 of the first surface 30aa, respectively
  • the second surface 30ab may include two second areas 30a2 and connected respectively on both ends of the first area 30a1 of the second surface 30ab.
  • the area of the first area 30a1 of the first surface 30aa may be smaller than the area of the first area 30a1 of the second surface 30ab.
  • the positive electrode active material layer 30 is provided on the first region 30a1 of the first surface 30aa and the first region 30a1 of the second surface 30ab of the positive electrode current collector 30a.
  • the positive active material layer 30, may include at least but not limited to lithium cobalt oxide, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium manganate, lithium nickel oxide, lithium iron manganese phosphate, lithium vanadium phosphate, and vanadium oxyphosphate One or more of lithium, lithium iron phosphate, and lithium-rich manganese-based materials.
  • the thickness of the positive electrode current collector 30a may be 3 micrometers to 15 micrometers, and the thickness of the positive electrode active material layer 30 may be 80 micrometers to 300 micrometers.
  • the ratio of the thickness of the positive electrode active material layer 30 to the thickness of the positive electrode current collector 30a may be 5 to 30, which is beneficial to reduce the proportion of the thickness of the positive electrode current collector 30a in the overall thickness of the battery, thereby facilitating the improvement of The energy density of the battery.
  • the positive electrode active material layer 30 includes a third portion 31 and a fourth portion 33 connected to the third portion 31 along the first direction X.
  • the fourth portion 33 includes a second surface 330 and a second end 331
  • the third portion 31 includes a fourth surface 310 .
  • the fourth surface 310 is connected to the second surface 330 through the second connection 301 .
  • the second end 331 is an end of the fourth portion 33 away from the second connection 301
  • the second end 331 is an end of the positive electrode active material layer 30 .
  • the thickness of the fourth portion 33 in the second direction Y decreases along the first direction X from the second connection 301 toward the second end 331 . That is, the second connection 301 is where the thickness of the fourth portion 33 in the second direction Y begins to decrease along the first direction X. In some embodiments, the thickness of the fourth portion 33 in the second direction Y decreases monotonically along the first direction X from the second connection 301 toward the second end 331 , wherein the thickness may decrease linearly or curvilinearly.
  • the second end 331 is located in the flat portion 100AA.
  • the positive active material layer 30 is disposed on the first region 30a1, and a second region 30a2 is disposed on the side of the second end 331 away from the second connection 301 in the first direction X.
  • the first surface 10aa of the negative electrode current collector 10a is provided facing the second surface 30ab of the positive electrode current collector 30a, and the second surface 10ab of the negative electrode current collector 10a is provided facing the first surface 30aa of the positive electrode current collector 30a.
  • the separator 50 is located between the anode active material layer 10 and the cathode active material layer 30 .
  • the isolation film 50 contains an electrically insulating material, for example, at least one or more of polyethylene, polypropylene, polyethylene terephthalate, polyimide, and aramid may be included but not limited to.
  • the polyethylene includes at least one component selected from the group consisting of high density polyethylene, low density polyethylene, and ultra-high molecular weight polyethylene. Especially polyethylene and polypropylene, they have a good effect on preventing short circuits and can improve the stability of lithium-ion batteries through the shutdown effect.
  • the surface of the separator can also include a porous layer, the porous layer is disposed on at least one surface of the separator, the porous layer includes inorganic particles and a binder, and the inorganic particles can be selected from but not limited to aluminum oxide (Al 2 O 3 ), oxide Silicon (SiO 2 ), magnesium oxide (MgO), titanium oxide (TiO 2 ), hafnium dioxide (HfO 2 ), tin oxide (SnO 2 ), ceria (CeO 2 ), nickel oxide (NiO), zinc oxide (ZnO), calcium oxide (CaO), zirconium oxide (ZrO 2 ), yttrium oxide (Y 2 O 3 ), silicon carbide (SiC), boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide and barium sulfate A combination of one or more of.
  • Al 2 O 3 aluminum oxide
  • SiO 2 oxide Silicon
  • MgO magnesium oxide
  • TiO 2 titanium oxide
  • HfO 2
  • the binder can be selected from but not limited to polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, A combination of one or more of polyvinylpyrrolidone, polyvinyl ether, polymethylmethacrylate, polytetrafluoroethylene, and polyhexafluoropropylene.
  • the porous layer can improve the heat resistance, oxidation resistance and electrolyte wettability of the separator, and enhance the adhesion between the separator and the positive electrode or negative electrode.
  • the isolation film 50 is a film layer including a plurality of holes. As shown in FIG. 2 , each disconnection on the isolation film 50 is a hole.
  • the separator 50 is not in contact with the negative electrode active material layer 10 and the positive electrode active material layer 30 respectively in the drawings, but in some embodiments, the separator 50 may be in contact with the negative electrode active material layer 10 and the positive electrode active material layer. At least a portion of 30 contacts.
  • the first end 131 is used as the end of the negative electrode active material layer 10 close to the end of the wound electrode assembly 100A, and the second end 331 is used as the positive active material layer 30 close to the end of the wound electrode assembly 100A. end of the description.
  • the negative electrode active material layer 10 and the positive electrode active material layer 30 are arranged to face each other.
  • the first surface 130 and the second surface 330 are at least partially disposed opposite to each other, that is, viewed from the second direction Y, the first surface 130 and the second surface 330 at least partially overlap.
  • the third surface 110 and the fourth surface 310 are disposed at least partially opposite to each other, that is, when viewed from the second direction Y, the third surface 110 and the fourth surface 310 at least partially overlap.
  • the first connection 101 is located between the second connection 301 and the second end 331 .
  • the thickness of the fourth portion 33 in the second direction Y decreases from the first connection 101 toward the first end 131 along the first direction X.
  • the decrease in the first direction X from the second connection 301 toward the second end 331 is beneficial to suppress the lithium deposition phenomenon while maintaining the energy density of the battery 100 .
  • the second end 331 may be located between the first connection 101 and the first end 131 , that is, viewed from the second direction Y, the first surface 130 and the second surface 330 are at least Partially overlap, thereby further helping to suppress the lithium deposition phenomenon in the battery.
  • the negative electrode active material layer 10 and the positive electrode active material layer 30 are separated.
  • the distance from the third surface 110 to the fourth surface 310 along the second direction Y is the first distance D1
  • the distance from the first surface 130 to the second surface 330 along the second direction Y is the second distance D2
  • the third surface 110 along the second direction Y is the second distance D2.
  • the distance from the two directions Y to the second surface 330 is the third distance D3.
  • D1 and D2 are not equal, and D1 and D3 are not equal.
  • D2 is greater than D1
  • D3 is greater than D1
  • D3 and D2 are not equal. More specifically, D3 is smaller than D2.
  • the first end 131 and the second end 331 may or may not be arranged in parallel.
  • the first end 131 in the third direction Z may be linear or non-zero-degree curved
  • the second end 331 may be linear or non-zero-degree curved.
  • FIG. 4a viewed from the second direction Y, the first end 131 has a first area with a first distance E1 from the second end 331 in the first direction X, and the first end 131 There is also a second area with a second distance E2 from the second end 331 in the first direction X. Among them, E1 and E2 are not equal.
  • FIG. 4 b is a partial cross-sectional top view of the plane along the X direction and the Z direction of the battery, and the cross section is the positive electrode active material layer 30 . In FIG. 4 b , the distance from one end of the positive electrode active material layer 30 close to the first end 131 to the first end 131 along the first direction X is greater than the distance from the second end 331 to the first end 131 along the first direction X.
  • the second end 331 may have a plurality of protrusions 333 , for example, the second end 331 may be, but not limited to, a wavy shape or a sawtooth shape.
  • the first end 131 may also have a plurality of protrusions 133 , for example, the first end 131 may be in but not limited to a wave shape or a zigzag shape.
  • the cell 100 may further include a first layer 60, which may contain an insulating material, and which may further contain a material that may limit ionic conduction.
  • the first layer 60 can limit the conduction of ions, for example, can block or block the conduction of ions.
  • the insulating material may be, but not limited to, single-sided tape and double-sided tape. In this case, the end of the first layer 60 can be prevented from being separated from the surface of the 30 .
  • the first layer 60 adheres to the second end 331 and the second surface 330 and continuously covers the second end 331 and the second surface 330, by inhibiting the lithium ions generated by the positive electrode active material layer 30 from reaching the opposite negative electrode active material layer 10. In order to inhibit the lithium deposition phenomenon of the battery.
  • the first layer 60 can also extend from the second surface 330 to the fourth surface 310 to bond the fourth surface 310 and cover the part of the fourth surface 310 to further suppress the generation of lithium from the positive electrode active material layer 30
  • the ions reach the negative electrode active material layer 10, thereby avoiding the phenomenon of lithium deposition.
  • the length of the part where the first layer 60 and the fourth surface 310 are bonded in the first direction X may be less than or equal to 5 mm, so as to reduce the loss of energy density while suppressing the lithium deposition phenomenon of the battery.
  • the first layer 60 can also extend from the second end 331 to the second area 30a2 to bond the second area 30a2 and cover at least a part of the second area 30a2, so as to facilitate warping at the edge of the first layer 60 At the beginning, it is ensured that the first layer 60 still adheres to the second end 331, thereby further suppressing the lithium deposition phenomenon of the battery. Meanwhile, when the first layer 60 is made of an insulating material, the first layer 60 covering the second region 30a2 can further reduce the probability of short circuit between the positive pole piece 30A and the negative pole piece 10A.
  • the surface of the first layer 60 facing away from the second end 331 correspondingly forms a crease 65 .
  • the crease 65 is located between the first end 131 and the second end 331 .
  • 9b is a partial cross-sectional plan view of the battery along the X direction and the Z direction, and the cross section is the positive electrode active material layer 30 and the first layer 60 bonded to the positive electrode active material layer 30 .
  • the distance from one end of the cathode active material layer 30 close to the first end 131 to the first end 131 along the first direction X is greater than the distance from the second end 331 to the first end 131 along the first direction X.
  • the first layer 60 includes a third end 62 and a fourth end 64 spaced in the first direction X and disposed opposite to each other.
  • the third end 62 is located on the side of the second connection 301 away from the second end 331
  • the fourth end 64 is located at the side of the second connection 301 away from the third end 62 .
  • the distance from the second end 331 to the third end 62 along the first direction X is the fourth distance F1 , and the distance from the second end 331 to the fourth end 64 along the first direction X
  • the distance is the fifth distance F2, wherein F1 and F2 are not equal.
  • F1 is smaller than F2.
  • the width of the first layer 60 along the Z direction is greater than the width of the positive active material layer 30 along the Z direction, which is beneficial to suppress the lithium deposition phenomenon of the battery.
  • the width of the first layer 60 along the Z direction is greater than the width of the positive electrode piece 30A along the Z direction, and at the same time greater than the width of the negative electrode piece 10A along the Z direction, which is conducive to further suppressing the lithium deposition phenomenon of the battery, and at the same time It is also beneficial to further reduce the probability of short circuit between the positive pole piece 30A and the negative pole piece 10A.
  • the width of the first layer 60 along the Z direction may be greater than, less than or equal to the negative electrode active material layer 30 .
  • the width of the substance layer 10 in the Z direction may be greater than, less than or equal to the negative electrode active material layer 30 .
  • the fourth surface 310 may include a third area 310 a , a discontinuity area 310 b and a fourth area 310 c connected in sequence along the first direction X.
  • the thickness H1 of the portion of the positive electrode active material layer 30 corresponding to the fourth region 310c in the second direction Y is smaller than the thickness H2 of the positive electrode active material layer 30 corresponding to the third region 310a.
  • the fourth region 310c is located between the discontinuity region 310b and the first connection 101 .
  • the first layer 60 covers the fourth region 310c, which is beneficial to reduce the influence of the arrangement of the first layer 60 on the thickness of the battery, thereby helping to improve the volumetric energy density of the battery.
  • the thickness H1 of the portion of the positive electrode active material layer 30 corresponding to the fourth region 310c in the second direction Y is greater than the height H3 of the discontinuity region 310b.
  • the discontinuity area 310b is a discontinuity plane connecting the third area 310a and the fourth area 310c, which may be an inclined curved surface.
  • the thickness H4 of the first layer 60 in the second direction Y may be greater than the height H3 of the discontinuity region 310b in the second direction Y.
  • the height of the discontinuity area 310b refers to the distance in the second direction Y from where the discontinuity area 310b meets the third area 310a to the second direction Y where the discontinuity area 310b meets the fourth area 310c.
  • the first layer 60 may also cover the discontinuity area 310b, or cover the discontinuity area 310b and portions of the third area 310a.
  • the portion of the first layer 60 in the fourth region 310c includes a fifth surface 66 that faces away from the fourth region 310c.
  • the fifth surface 66 includes a portion where the distance G1 in the second direction Y to the third region 310a is greater than the distance G2 in the second direction Y to the third surface 110 .
  • the fourth surface 310 can also be a flat surface.
  • the first end 131 can also be used as one end of the negative electrode active material layer 10 close to the starting section of the wound electrode assembly 100A, and the second end 331 can also be used as a positive electrode
  • the active material layer 30 is close to one end of the starting section of the wound electrode assembly 100A.
  • the thickness of the second portion in the second direction gradually decreases along the first direction from the first connection to the first end, and the thickness of the fourth portion in the second direction decreases from the first end along the first direction.
  • the second connection gradually decreases toward the second end, which is beneficial to improve the energy density of the battery; while in the first direction, the first connection is located between the second connection and the second end, which is beneficial to inhibit the precipitation of the battery. Lithium phenomenon. Therefore, the structure of the battery of the present application is beneficial to suppress the lithium deposition phenomenon while maintaining the energy density of the battery.

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Abstract

一种电池，包括负极活性物质层、正极活性物质层及位于正极活性物质层和负极活性物质层之间的隔离膜。负极活性物质层包括第一部分和第二部分。第二部分包括第一表面和第一端。第一表面通过第一连接处连接第一部分，第一端背离第一连接处且为负极活性物质层的一端。第二部分的厚度自第一连接处朝第一端减小。正极活性物质层包括第三部分和第四部分，第四部分包括第二表面和第二端。第二表面与第二表面至少部分相向，且通过第二连接处连接第三部分，第二端背离第二连接处且为正极活性物质层的一端。第四部分的厚度自第二连接处朝第二端逐渐减小。第一连接处位于第二连接处和第二端之间。本申请的电池有利于在维持电池能量密度的同时抑制析锂现象。

Description

电池 技术领域
本申请涉及一种电池。
背景技术
锂离子电池具有能量密度大、循环寿命长、标称电压高、自放电率低、体积小、重量轻等许多优点，在消费电子领域具有广泛的应用。在锂电池中，为了抑制析锂现象，通常负极极片的活性物质层的尺寸会比正极极片的活性物质层的尺寸更大。另一方面，从提高锂电池的能量密度的观点来看，负极极片的活性物质层和正极极片的活性物质层之间的尺寸的差距则越小越好。但是，在维持负极极片的活性物质层边缘超出正极极片的活性物质层边缘的同时做到负极极片的活性物质层和正极极片的活性物质层之间的尺寸的差距尽量小，在制造工艺上，特别是卷绕型电池的工艺上来说，导致对制造工艺精度的要求较高，否则会导致电池负极极片的边缘出现析锂现象，降低电池的安全性能。
发明内容
鉴于上述情况，有必要提供一种有利于抑制析锂现象发生且同时保持较高能量密度的电池。
本申请提供了一种电池，包括负极活性物质层、正极活性物质层以及位于正极活性物质层和负极活性物质层之间的隔离膜。负极活性物质层沿第一方向包括第一部分和连接第一部分的第二部分。第二部分包括第一表面和第一端。第一表面通过第一连接处连接第一部分，第一端背离第一连接处且为负极活性物质层的一端。第二部分在垂直于第一方向的第二方向上的厚度沿第一方向自第一连接处朝第一端逐渐减小。正极活性物质层沿第一方向包括第三部分和连接第三部分的第四部分，第四部分包括第二表面和第二端。第二表面通过第二连接处连接第三部分，第二端背离第二连接处且为正极活性物质层的一端。第四部分在第二方向上的厚度沿第一方向自第二连接处朝第二端逐渐减小。第一表面与第二表面至少部分相向设置，且在第一方向上，第一连接处位于第二连接处和第二端之间。
作为本申请的一种方案，在第一方向上，第二端位于第一连接处与第一端之间。
作为本申请的一种方案，第一部分包括第三表面，第三部分包括第四表面。第三表面与第一表面通过第一连接处连接，第四表面与第二表面通过第二连接处连接；第三表面和第四表面至少部分相向设置。
作为本申请的一种方案，第三表面和第四表面在第二方向上至少部分重合；第一表面和第二表面在第二方向上至少部分重合；第三表面和第二表面在第二方向上至少部分重合。
作为本申请的一种方案，第三表面沿第二方向至第四表面的距离为第一距离，第一表面沿第二方向至第二表面的距离为第二距离，其中，第一距离与第二距离不相等。
作为本申请的一种方案，第一距离小于第二距离。
作为本申请的一种方案，第三表面沿第二方向至第二表面的距离为第三距离，其中，第三距离与第一距离不相等。
作为本申请的一种方案，第三距离大于第一距离。
作为本申请的一种方案，第三距离与第二距离不相等。
作为本申请的一种方案，第三距离小于第二距离。
作为本申请的一种方案，沿第二方向观察，第一端具有与第二端在第一方向上的间距为第一间距的第一区，以及具有与第二端在第一方向的间距为第二间距的第二区，其中，第一间距与第二间距不相等。
作为本申请的一种方案，沿第二方向观察，第二端具有多个凸起。
作为本申请的一种方案，电池还包括第一层，第一层粘接第二端和第二表面，并连续覆盖第二端和第二表面，第一层能够阻挡离子的传导。
作为本申请的一种方案，第一层还粘接第四表面并覆盖第四表面的至少部分。
作为本申请的一种方案，电池还包括正极集流体，正极集流体位于正极活性物质层背离第一表面和第三表面的一侧，且正极集流体包括设置所述正极活性物质层的第一区和在第一方向上位于第二端背离第二连接处的一侧的第二区，所述第二区未设置所述正极活性物质层，第一层还粘接第二区并覆盖第二区的至少部分。
作为本申请的一种方案，第一层在第一方向上包括相背设置第三端和第四端，在第一方向上，第三端位于第二连接处背离第二端的一侧，第四端位于第二连接处背离第三端的一侧，其中，沿第二方向上观察，第二端至第三端部的距离为第四距离，第二端至第四端部的距离为第五距离，且第四距离与第五距离不相等。
作为本申请的一种方案，第四距离小于第五距离。
作为本申请的一种方案，第四表面包括沿第一方向依次连接的第三区、断差区和第四区，正极活性物质层对应第四区的部分在第二方向的厚度小于正极活性物质层对应第三区的厚度；从第二方向观察，第四区位于断差区与第一连接处之间，且第一层覆盖第四区。
作为本申请的一种方案，第一层在第二方向上的厚度大于断差区在第二方向上的高度。
作为本申请的一种方案，阻挡第一层位于第四区的部分包括第五表面，第五表面背离第四区，第五表面包括在第二方向上至第三区的距离大于在第二方向上至第三表面的距离的部分。
本申请的电池，其中，在第一方向上使负极活性物质层的第一连接处位于正极活性物质层的第二连接处与正极活性物质层的第二端之间，有利于在 维持电池能量密度的同时抑制析锂现象。
附图说明
图1为本申请一实施方式的电池的结构示意图。
图2为本申请一实施方式的电池的剖面示意图。
图3为本申请一实施方式的电池在图2中的III位置处的局部放大示意图。
图4a为本申请一实施方式的电池在图2中的III位置处的局部俯视示意图。
图4b为本申请一实施方式的电池沿图3中的IV-IV方向的局部剖面图。
图5为本申请一实施方式的电池在图2中的III位置处的局部俯视示意图。
图6为本申请一实施方式的电池在图2中的III位置处的局部俯视示意图。
图7为本申请一实施方式的电池在图2中的III位置处的剖面示意图。
图8为本申请一实施方式的电池在图7中的VIII位置处的局部放大示意图。
图9a为本申请一实施方式的电池在图7中的VIII位置处的局部俯视示意图。
图9b为本申请一实施方式的电池沿图8中的IX-IX方向的局部剖面图。
图10为本申请一实施方式的电池在图7中的VIII位置处的局部放大示意图。
图11为本申请的一实施方式的电池在图2中的XI位置处的局部放大示意图。
图12为本申请的一实施方式的电池在图2中的XI位置处的局部俯视示意图。
主要元件符号说明
电池 100
电极组件 100A
主平面 100B
负极极片 10A
正极极片 30A
隔离膜 50
负极活性物质层 10
负极集流体 10a
第一区 10a1、30a1
第二区 10a2、30a2
第一方向 X
第一部分 11
第二部分 13
第一表面 130
第一端 131
第三表面 110
第一连接处 101
第二方向 Y
第三方向 Z
正极活性物质层 30
正极集流体 30a
第三部分 31
第四部分 33
第二表面 330
第二端 331
第四表面 310
第二连接处 301
中心轴线 O-O
扁平部 100AA
弯折端部 100AB
凸起 333、133
第一层 60
第三端 62
第四端 64
第三区 310a
断差区 310b
第四区 310c
第五表面 66
第1面 10aa、30aa
第2面 10ab、30ab
折痕 65
如下具体实施方式将结合上述附图进一步说明本申请。
具体实施方式
下面对本申请实施例中的技术方案进行清楚、详细地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同。在本申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请。
下文，将详细地描述本申请的实施方式。但是，本申请可体现为许多不同的形式，并且不应解释为限于本文阐释的示例性实施方式。而是，提供这些示例性实施方式，从而使本申请透彻的和详细的向本领域技术人员传达。
另外，为了简洁和清楚，在附图中，各种组件、层的尺寸或厚度可被放大。遍及全文，相同的数值指相同的要素。如本文所使用，术语“及/或”、“以及/或者”包括一个或多个相关列举项目的任何和所有组合。另外，应当理解，当要素A被称为“连接”要素B时，要素A可直接连接至要素B，或可能存在中间要素C并且要素A和要素B可彼此间接连接。
进一步，当描述本申请的实施方式时使用“可”指“本申请的一个或多个实施方式”。
本文使用的专业术语是为了描述具体实施方式的目的并且不旨在限制本申请。如本文所使用，单数形式旨在也包括复数形式，除非上下文另外明确指出。应进一步理解，术语“包括”，当在本说明书中使用时，指存在叙述的特征、数值、步骤、操作、要素和/或组分，但是不排除存在或增加一个或多个其他特征、数值、步骤、操作、要素、组分和/或其组合。
空间相关术语，比如“上”等可在本文用于方便描述，以描述如图中阐释的一个要素或特征与另一要素(多个要素)或特征(多个特征)的关系。应理解，除了图中描述的方向之外，空间相关术语旨在包括设备或装置在使用或操作中的不同方向。例如，如果将图中的设备翻转，则描述为在其他要素或特征“上方”或“上”的要素将定向在其他要素或特征的“下方”或“下面”。因此，示例性术语“上”可包括上面和下面的方向。
应理解，当元件或层被称作“在”另一元件或层“上”、“与”另一元件或层“连接”、“与”另一元件或层“结合”或者“邻近于”另一元件或层时，该元件或层可能“直接在”另一元件或层“上”、“直接结合到”另一元件或层、“直接与”另一元件或层“连接”、“直接与”另一元件或层“结合”或“直接邻近于”另一元件或层，或者可能存在一个或更多个中间元件或中间层。此外，“连接”、“所连接的”等也可以基于它们被用作本领域技术人员将理解的内容而表示“电连接”、“电气地连接”等。此外，当一个元件、组件、区域、层和/或部分被称作“在”两个元件、组件、区域、层和/或部分之间时，它可以是这两个元件、组件、区域、层和/或部分之间的唯一元件、组件、区域、层和/或部分，或者也可以存在一个或更多个中间元件、组件、区域、层和/或部分。
应理解，尽管术语第一、第二、第三等可在本文用于描述各种要素、组分、区域、层和/或部分，但是这些要素、组分、区域、层和/或部分不应受这些术语的限制。这些术语用于区分一个要素、组分、区域、层或部分与另 一要素、组分、区域、层或部分。因此，下面讨论的第一要素、组分、区域、层或部分可称为第二要素、组分、区域、层或部分，而不背离示例性实施方式的教导。
在本申请中，第一方向X和第三方向Z相互垂直且平行于电极组件的主平面，第二方向Y垂直于电极组件的主平面，即为电极组件的厚度方向。电极组件的主平面为电极组件的扁平部的表面(图1中的100B)。电极组件的厚度方向为电极组件的扁平部中各极片的层叠方向。
下面对本申请的一些实施方式作详细说明。在不冲突的情况下，下述的实施例及实施例中的特征可以相互组合。
请参阅图1和图2，电池100包括电极组件100A。图2为图1中电池100沿X方向和Y方向所在平面的截面，电极组件100A包括负极极片10A、正极极片30A以及位于正极极片10A和负极极片30A之间的隔离膜50。隔离膜50为电绝缘材料，且离子能穿过隔离膜50。
下面对负极极片10A和正极极片30A的位置关系进行进一步地说明。
如图1所示，负极极片10A、隔离膜50和正极极片30A层叠形成堆叠体，再由堆叠体绕沿第三方向Z的中心轴线O-O经过多次卷绕形成电极组件100A。
电极组件100A包括扁平部100AA和在X方向上存在多个弯折端部100AB，多个弯折端部100AB分别分布于电池100的扁平部100AA沿X方向的中心的相对两侧，在图2中，分别为左右两侧。
下面对负极极片10A进行进一步地说明。
请参阅图2，负极极片10A包括负极活性物质层10和负极集流体10a。负极活性物质层10设置负极集流体10a的表面。
负极集流体10a导电，其包括导电材料。导电材料，例如，至少可以包括镍、铜等导电金属及其合金中的至少一种或多种。在一些实施方式中，负极集流体10a，例如，至少可以包括但不限于镍箔、铜箔等导电金属薄板中的一种或两种。负极集流体10a包括相背的第1面10aa和第2面10ab。负极集流体10a的第1面10aa包括第一区10a1和第二区10a2，负极集流体10a的第2面10ab包括第一区10a1和第二区10a2。第一区10a1为用于设置活性材料形成活性物质层的区域，第二区10a2则为未形成活性物质层的区域。在一些实施方式中，第1面10aa可包括两个第二区10a2且分别连接于第1面10aa的第一区10a1的两端，第2面10ab可包括两个第二区10a2且分别连接于第2面10ab的第一区10a1的两端。第1面10aa的第一区10a1的面积可大于第2面10ab的第一区10a1的面积。
负极活性物质层10设置于负极集流体10a的第1面10aa的第一区10a1和第2面10ab的第一区10a1。负极活性物质层10，例如，至少可包括但不仅限于石墨、软碳、硬碳、石墨烯、中间相碳微球、硅基材料、锡基材料、钛酸锂或其他能与锂形成合金的金属中的一种或多种。
优选的，负极集流体10a的厚度可为2微米至13微米，负极活性物质 层10的厚度可为80微米至300微米。
在一些实施方式中，负极活性物质层10的厚度与负极集流体10a的厚度的比值可为5至30，有利于减小电池的整体厚度中负极集流体10a的厚度占比，从而有利于提升电池的能量密度。
请同时参阅图3，负极活性物质层10沿第一方向X包括第一部分11和连接第一部分11的第二部分13。第二部分13包括第一表面130和第一端131，第一部分11包括第三表面110。其中，第三表面110通过第一连接处101连接第一表面130。第一端131为第二部分13背离第一连接处101的一端，且第一端131为负极活性物质层10的一端。
第二部分13在垂直于第一方向X的第二方向Y上的厚度沿第一方向X自第一连接处101朝第一端131递减。即第一连接处101为第二部分13在第二方向Y上的厚度沿第一方向X开始减少之处。在一些实施方式中，第二部分13在第二方向Y上的厚度沿第一方向X自第一连接处101朝第一端131单调递减，其中，可为线性递减或曲线式递减。
沿第二方向Y观察，第一端131位于所述扁平部100AA中。负极活性物质层10设置于第一区10a1上，在第一方向X上位于第一端131背离第一连接处101的一侧设有第二区10a2。
下面对正极极片30A进行进一步地说明。
请参阅图2，正极极片30A包括正极活性物质层30和正极集流体30a。正极活性物质层30设置于正极集流体30a的表面。
正极集流体30a导电，其包括导电材料。导电材料，例如至少可以包括铝、铜、镍等导电金属及其合金中的至少一种或多种。在一些实施方式中，正极集流体30a，例如，至少可以包括但不限于铝网、铝箔、铜网、铜箔、镍箔等导电金属薄板中的一种或多种。正极集流体30a包括相背的第1面30aa和第2面30ab。正极集流体30a的第1面30aa包括第一区30a1和第二区30a2，正极集流体30a的第2面30ab包括第一区30a1和第二区30a2。第一区30a1为用于设置活性材料形成活性物质层的区域，第二区30a2则为未形成活性物质层的区域。在一些实施方式中，第1面30aa可包括两个第二区30a2且分别连接于第1面30aa的第一区30a1的两端，第2面30ab可包括两个第二区30a2且分别连接于第2面30ab的第一区30a1的两端。第1面30aa的第一区30a1的面积可小于第2面30ab的第一区30a1的面积。
正极活性物质层30设置于正极集流体30a的第1面30aa的第一区30a1和第2面30ab的第一区30a1。正极活性物质层30，例如，至少可包括但不仅限于钴酸锂、镍钴锰酸锂、镍钴铝酸锂、锰酸锂、镍酸锂、磷酸锰铁锂、磷酸钒锂、磷酸钒氧锂、磷酸铁锂和富锂锰基材料中的一种或多种。
优选的，正极集流体30a的厚度可为3微米至15微米，正极活性物质层30的厚度可为80微米至300微米。
在一些实施方式中，正极活性物质层30的厚度与正极集流体30a的厚度的比值可为5至30，有利于减小电池的整体厚度中正极集流体30a的厚度 占比，从而有利于提升电池的能量密度。
请同时参阅图3，正极活性物质层30沿第一方向X包括第三部分31和连接第三部分31的第四部分33。第四部分33包括第二表面330和第二端331，第三部分31包括第四表面310。其中，第四表面310通过第二连接处301连接第二表面330。第二端331为第四部分33背离第二连接处301的一端，且第二端331为正极活性物质层30的一端。
第四部分33在第二方向Y上的厚度沿第一方向X自第二连接处301朝第二端331递减。即第二连接处301为第四部分33在第二方向Y上的厚度沿第一方向X开始减少之处。在一些实施方式中，第四部分33在第二方向Y上的厚度沿第一方向X自第二连接处301朝第二端331单调递减，其中，可为线性递减或曲线式递减。
沿第二方向Y观察，第二端331位于扁平部100AA中。
正极活性物质层30设置于第一区30a1上，在第一方向X上位于第二端331背离第二连接处301的一侧设有第二区30a2。
在本实施方式中，负极集流体10a的第1面10aa朝向正极集流体30a的第2面30ab设置，负极集流体10a的第2面10ab朝向正极集流体30a的第1面30aa设置。
隔离膜50位于负极活性物质层10和正极活性物质层30之间。隔离膜50含有电绝缘材料，例如，至少可以包括但不限于聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯、聚酰亚胺和芳纶中的一种或多种。举例来说，聚乙烯包括选自高密度聚乙烯、低密度聚乙烯和超高分子量聚乙烯中的至少一种组分。尤其是聚乙烯和聚丙烯，它们对防止短路具有良好的作用，并可以通过关断效应改善锂离子电池的稳定性。
隔离膜的表面还可包括多孔层，多孔层设置在隔离膜的至少一个表面上，多孔层包括无机颗粒和粘结剂，无机颗粒可选自但不仅限于氧化铝(Al 2O 3)、氧化硅(SiO 2)、氧化镁(MgO)、氧化钛(TiO 2)、二氧化铪(HfO 2)、氧化锡(SnO 2)、二氧化铈(CeO 2)、氧化镍(NiO)、氧化锌(ZnO)、氧化钙(CaO)、氧化锆(ZrO 2)、氧化钇(Y 2O 3)、碳化硅(SiC)、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙和硫酸钡中的一种或多种的组合。粘结剂可选自但不仅限于聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、羧甲基纤维素钠、聚乙烯呲咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯和聚六氟丙烯中的一种或多种的组合。
多孔层可以提升隔离膜的耐热性能、抗氧化性能和电解液浸润性能，增强隔离膜与正极或负极之间的粘接性。
在本实施方式中，隔离膜50为包含多个孔洞的膜层，如图2所示，隔离膜50上每一断开处即为一孔洞。
在本实施方式中，附图中隔离膜50分别与负极活性物质层10以及正极活性物质层30不接触，但是在一些实施方式中，隔离膜50可与负极活性物 质层10以及正极活性物质层30中的至少一部分接触。
下面以第一端131作为负极活性物质层10靠近卷绕式的电极组件100A的收尾段的一端，第二端331作为正极活性物质层30靠近卷绕式的电极组件100A的收尾段即III处的一端进行说明。
负极活性物质层10和正极活性物质层30相向设置。具体的，请参阅图3，第一表面130与第二表面330至少部分相向设置，即从第二方向Y观察，第一表面130和第二表面330至少部分重合。第三表面110与第四表面310至少部分相向设置，即从第二方向Y观察，第三表面110和第四表面310至少部分重合。在第一方向X上，第一连接处101位于第二连接处301和第二端331之间。结合第二部分13在垂直于第一方向X的第二方向Y上的厚度沿第一方向X自第一连接处101朝第一端131递减，第四部分33在第二方向Y上的厚度沿第一方向X自第二连接处301朝第二端331递减，有利于在维持电池100的能量密度的同时抑制析锂现象。
在本实施方式中，在第一方向X上，第二端331可位于第一连接处101与第一端131之间，即从第二方向Y观察，第一表面130和第二表面330至少部分重合，从而进一步地有利于抑制电池中的析锂现象。
负极活性物质层10和正极活性物质层30隔开。第三表面110沿第二方向Y至第四表面310的距离为第一距离D1，第一表面130沿第二方向Y至第二表面330的距离为第二距离D2，第三表面110沿第二方向Y至第二表面330的距离为第三距离D3。其中，D1与D2不相等，D1与D3不相等。具体的，D2大于D1，D3大于D1，D3与D2不相等。更具体的，D3小于D2。
请参阅图4a、图5和图6，从第二方向Y观察，第一端131与第二端331可平行设置也可不平行设置。从第二方向Y观察，第一端131在第三方向Z上可呈直线状也可呈非零度的曲线状，第二端331可呈直线状也可呈非零度的曲线状。
在本实施方式中，请参阅图4a，从第二方向Y观察，第一端131具有与第二端331在第一方向X上的间距为第一间距E1的第一区，第一端131还具有与第二端331在第一方向X上的间距为第二间距E2的第二区。其中，E1与E2不相等。图4b为电池沿X方向和Z方向所在平面的局部剖面俯视图，剖面为正极活性物质层30。在图4b中，正极活性物质层30靠近第一端131的一端沿第一方向X至第一端131的距离大于第二端331沿第一方向X至至第一端131的距离。
具体的，请参阅图4a和图6，从第二方向Y观察，第二端331可具有多个凸起333，例如，第二端331可呈但不仅限于波浪状或者锯齿状等。同样，第一端131也可具有多个凸起133，例如，第一端131可呈但不仅限于波浪状或者锯齿状等。
在一些实施方式中，请参阅图7至图9a，电池100还可包括第一层60，第一层60可含有绝缘材料，第一层60还可含有可限制离子传导的材料。其 中，第一层60可限制离子的传导，例如，可阻挡或隔绝离子的传导。在一些实施方式中，绝缘材料可为但不仅限于单面胶纸、双面胶纸，此时，可以避免第一层60的端部从30的表面脱离。
第一层60粘接第二端331和第二表面330，并连续覆盖第二端331和第二表面330，通过抑制正极活性物质层30产生的锂离子达到相对的负极活性物质层10的方式以抑制电池的析锂现象。
在本实施方式中，第一层60还可自第二表面330延伸至第四表面310以粘接第四表面310并覆盖第四表面310的部分，进一步地抑制正极活性物质层30产生的锂离子达到负极活性物质层10，进而避免析锂现象。
优选的，第一层60与第四表面310粘接的部分在第一方向X上的长度可小于或等于5mm，以便于在抑制电池的析锂现象的同时降低能量密度损失。
在本实施方式中，第一层60还可自第二端331延伸至第二区30a2以粘接第二区30a2并覆盖第二区30a2的至少部分，以便于在第一层60的边缘翘起时保证第一层60依旧粘接第二端331，从而进一步地抑制了电池的析锂现象。同时，当第一层60为绝缘材料制得时，第一层60覆盖第二区30a2可进一步地降低正极极片30A和负极极片10A的短路的概率。第一层60自第二端331延伸至第二区30a2并覆盖第二区30a2时，第一层60背离第二端331的表面对应形成折痕65。沿第二方向Y观察，折痕65位于第一端131与第二端331之间。
图9b为电池沿X方向和Z方向所在平面的局部剖面俯视图，剖面为正极活性物质层30以及和正极活性物质层30粘接的第一层60。在图9b中，正极活性物质层30靠近第一端131的一端沿第一方向X至第一端131的距离大于第二端331沿第一方向X至至第一端131的距离。
第一层60包括在第一方向X上间隔且相背设置的第三端62和第四端64。在第一方向X上，第三端62位于第二连接处301背离第二端331的一侧，第四端64位于第二连接处301背离第三端62的一侧。
如图7所示，沿第二方向Y观察，第二端331沿第一方向X至第三端62的距离为第四距离F1，第二端331沿第一方向X至第四端64的距离为第五距离F2，其中，F1与F2不相等。优选的，F1小于F2。
如图9a和图9b所示，从第二方向Y观察，第一层60沿Z方向上的宽度大于正极活性物质层30沿Z方向上的宽度，从而有利于抑制电池的析锂现象。优选地，第一层60沿Z方向上的宽度大于正极极片30A沿Z方向上的宽度，同时大于负极极片10A沿Z方向上的宽度，有利于进一步地抑制电池的析锂现象，同时也有利于进一步地降低正极极片30A和负极极片10A的短路的概率。在一些实施方式中，第一层60沿Z方向上的宽度大于正极活性物质层30沿Z方向上的宽度的基础上，第一层60沿Z方向上的宽度可大于、小于或者等于负极活性物质层10沿Z方向上的宽度。
在一些实施方式中，请参阅图10，第四表面310可包括沿第一方向X 依次连接的第三区310a、断差区310b和第四区310c。其中，正极活性物质层30对应第四区310c的部分在第二方向Y的厚度H1小于正极活性物质层30对应第三区310a的厚度H2。从第二方向Y观察，第四区310c位于断差区310b与第一连接处101之间。第一层60覆盖第四区310c，有利于降低第一层60的设置对电池厚度的影响，从而有利于提升电池的体积能量密度。
优选的，在第二方向Y上，正极活性物质层30对应第四区310c的部分在第二方向Y的厚度H1大于断差区310b的高度H3。
在一些实施方式中，如图10所示，断差区310b为一连接第三区310a及第四区310c的断差面，其可为一倾斜的曲面。
优选的，第一层60在第二方向Y上的厚度H4可大于断差区310b在第二方向Y上的高度H3。此处，断差区310b的高度是指断差区310b与第三区310a相接处至断差区310b与第四区310c相接处在第二方向Y上的间距。
在一些实施方式中，第一层60也可覆盖断差区310b，或者覆盖断差区310b以及第三区310a的部分。
第一层60位于第四区310c的部分包括第五表面66，第五表面66背离第四区310c。在一些实施方式中，第五表面66包括在第二方向Y上至第三区310a的距离G1大于在第二方向Y上至第三表面110的距离G2的部分。
在一些实施方式中，第四表面310也可为一平整的表面。
在一些实施方式中，请参阅图11及图12，第一端131也可作为负极活性物质层10靠近卷绕式的电极组件100A的起始段的一端，同时，第二端331可作为正极活性物质层30靠近卷绕式的电极组件100A的起始段的一端。
本申请的电池，其中，第二部分在第二方向上的厚度沿第一方向自第一连接处朝第一端逐渐减小，第四部分在第二方向上的厚度沿第一方向自第二连接处朝第二端逐渐减小，从而有利于提升电池的能量密度；而在第一方向上，第一连接处位于第二连接处和第二端之间，则有利于抑制电池的析锂现象。因此，本申请的电池的结构有利于在维持电池的能量密度的同时抑制析锂现象。
另外，对于本领域的普通技术人员来说，可以根据本申请的技术构思做出其它各种相应的改变与变形，而所有这些改变与变形都应属于本申请的保护范围。

Claims (21)

  1. 一种电池，包括：负极活性物质层、正极活性物质层以及位于所述正极活性物质层和所述负极活性物质层之间的隔离膜；其中，
    所述负极活性物质层沿第一方向包括第一部分和连接所述第一部分的第二部分，所述第二部分包括第一表面和第一端，所述第一表面通过第一连接处连接所述第一部分，所述第一端背离所述第一连接处且为所述负极活性物质层的一端，所述第二部分在垂直于所述第一方向的第二方向上的厚度沿所述第一方向自所述第一连接处朝所述第一端减小；
    所述正极活性物质层沿所述第一方向包括第三部分和连接所述第三部分的第四部分，所述第四部分包括第二表面和第二端，所述第二表面通过第二连接处连接所述第三部分，所述第二端背离所述第二连接处且为所述正极活性物质层的一端，所述第四部分在所述第二方向上的厚度沿所述第一方向自所述第二连接处朝所述第二端逐渐减小；
    所述第一表面与所述第二表面至少部分相向设置，且在所述第一方向上，所述第一连接处位于所述第二连接处和所述第二端之间。
  2. 如权利要求1所述的电池，其中，在所述第一方向上，所述第二端位于所述第一连接处与所述第一端之间。
  3. 如权利要求1所述的电池，其中，所述第一部分包括第三表面，所述第三部分包括第四表面，所述第三表面与所述第一表面通过所述第一连接处连接，所述第四表面与所述第二表面通过所述第二连接处连接；所述第三表面和所述第四表面至少部分相向设置。
  4. 如权利要求3所述的电池，其中，所述第三表面和所述第四表面在所述第二方向上至少部分重合；所述第一表面和所述第二表面在所述第二方向上至少部分重合；所述第三表面和所述第二表面在所述第二方向上至少部分重合。
  5. 如权利要求4所述的电池，其中，所述第三表面沿所述第二方向至所述第四表面的距离为第一距离，所述第一表面沿所述第二方向至所述第二表面的距离为第二距离，其中，所述第一距离与所述第二距离不相等。
  6. 如权利要求5所述的电池，其中，所述第一距离小于所述第二距离。
  7. 如权利要求5所述的电池，其中，所述第三表面沿所述第二方向至所述第二表面的距离为第三距离，其中，所述第三距离与所述第一距离不相等。
  8. 如权利要求7所述的电池，其中，所述第三距离大于所述第一距离。
  9. 如权利要求7所述的电池，其中，所述第三距离与所述第二距离不相等。
  10. 如权利要求7所述的电池，其中，所述第三距离小于所述第二距离。
  11. 如权利要求1所述的电池，其中，沿所述第二方向观察，所述第一 端具有与所述第二端在所述第一方向上的间距为第一间距的第一区，以及具有与所述第二端在所述第一方向的间距为第二间距的第二区，其中，所述第一间距与所述第二间距不相等。
  12. 如权利要求1所述的电池，其中，沿所述第二方向观察，所述第二端具有多个凸起。
  13. 如权利要求3所述的电池，其中，所述电池还包括第一层，所述第一层粘接所述第二端和所述第二表面，并连续覆盖所述第二端和所述第二表面。
  14. 如权利要求13所述的电池，其中，所述第一层能够阻挡离子的传导，所述第一层包括单面胶纸或双面胶纸中的至少一种。
  15. 如权利要求13所述的电池，其中，所述第一层还粘接所述第四表面并覆盖所述第四表面的至少部分。
  16. 如权利要求13所述的电池，其中，所述电池还包括正极集流体，所述正极集流体位于所述正极活性物质层背离所述第一表面和所述第三表面的一侧，且所述正极集流体包括设置所述正极活性物质层的第一区和在所述第一方向上位于所述第二端背离所述第二连接处的一侧的第二区，所述第二区未设置所述正极活性物质层，所述第一层还粘接所述第二区并覆盖所述第二区的至少部分。
  17. 如权利要求16所述的电池，其中，所述第一层在所述第一方向上包括相背设置第三端和第四端，在所述第一方向上，所述第三端位于所述第二连接处背离所述第二端的一侧，所述第四端位于所述第二连接处背离所述第三端的一侧，其中，沿所述第二方向观察，所述第二端至所述第三端的距离为第四距离，所述第二端至所述第四端的距离为第五距离，且所述第四距离与所述第五距离不相等。
  18. 如权利要求17所述的电池，其中，所述第四距离小于所述第五距离。
  19. 如权利要求13所述的电池，其中，所述第四表面包括沿所述第一方向依次连接的第三区、断差区和第四区，所述正极活性物质层对应所述第四区的部分在所述第二方向的厚度小于所述正极活性物质层对应所述第三区的厚度；从所述第二方向观察，所述第四区位于所述断差区与所述第一连接处之间，且所述第一层覆盖所述第四区。
  20. 如权利要求19所述的电池，其中，所述第一层在所述第二方向上的厚度大于所述断差区在所述第二方向上的高度。
  21. 如权利要求20所述的电池，其中，所述第一层位于所述第四区的部分包括第五表面，所述第五表面背离所述第四区，所述第五表面包括在所述第二方向上至所述第三区的距离大于在所述第二方向上至所述第三表面的距离的部分。
PCT/CN2021/076082 2021-02-08 2021-02-08 电池 WO2022165850A1 (zh)

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