WO2025011306A1 - 电极组件、电芯和用电设备 - Google Patents

电极组件、电芯和用电设备 Download PDF

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Publication number
WO2025011306A1
WO2025011306A1 PCT/CN2024/100768 CN2024100768W WO2025011306A1 WO 2025011306 A1 WO2025011306 A1 WO 2025011306A1 CN 2024100768 W CN2024100768 W CN 2024100768W WO 2025011306 A1 WO2025011306 A1 WO 2025011306A1
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WIPO (PCT)
Prior art keywords
layer
electrode assembly
diaphragm
insulating member
pole piece
Prior art date
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Application number
PCT/CN2024/100768
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English (en)
French (fr)
Inventor
张国文
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Ningde Amperex Technology Ltd
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Ningde Amperex Technology Ltd
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Publication of WO2025011306A1 publication Critical patent/WO2025011306A1/zh
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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M10/05—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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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 and an electrical device.
  • Battery cells are widely used in portable electronic devices, electric vehicles, electric tools, drones, energy storage devices and other fields.
  • the reliability of battery cells is an issue that cannot be ignored. Therefore, how to improve the reliability of battery cells is a technical problem that needs to be solved urgently in battery cell technology.
  • the present application provides an electrode assembly, a battery cell and an electrical device, wherein the electrode assembly can effectively improve the reliability of the battery cell.
  • an embodiment of the present application provides an electrode assembly, which is a wound structure, comprising a first pole piece, a second pole piece and a diaphragm, wherein the diaphragm is disposed between the first pole piece and the second pole piece, the first pole piece comprising a first winding starting end, the diaphragm comprising a second winding starting end, and along the winding direction of the electrode assembly, a distance between the first winding starting end and the second winding starting end does not exceed 5 mm; wherein the electrode assembly further comprises an insulating member, wherein the insulating member is disposed between the innermost circle of the second pole piece and the first winding starting end to separate the first winding starting end from the second pole piece.
  • the diaphragm shrinks, and the first winding starting end and the second winding starting end that were originally flush with each other are no longer flush or the distance between them becomes larger, so that the first winding starting end is exposed from between the two layers of diaphragms. Due to the insulating member arranged between the first winding starting end and the innermost circle of the second pole piece, the first winding starting end will not contact the second pole piece to cause a short circuit.
  • the innermost circle of the second pole piece includes a first corner section, the first corner section is arranged opposite to the first winding start end, and at least a portion of the insulating member is arranged between the first corner section and the first winding start end. Since at least a portion of the insulating member is arranged between the first corner section and the first winding start end, even if the diaphragm shrinks and the first winding start end protrudes from the second winding start end, the first winding start end will be insulated.
  • the edge piece blocks the positive and negative electrodes from short-circuiting due to the first winding starting end contacting the first corner section.
  • the diaphragm includes a first diaphragm and a second diaphragm located on both sides of the first pole piece; the insulating member bypasses the first winding start end, and the two ends of the insulating member are respectively connected to the first diaphragm and the second diaphragm. Since the insulating member bypasses the first winding start end and is respectively connected to the first diaphragm and the second diaphragm, the shrinkage of the diaphragm can be restricted, effectively alleviating the problem of the first winding start end extending from the second winding start end.
  • the innermost circle of the second pole piece includes a first straight section and a second straight section
  • the first corner section connects the first straight section and the second straight section
  • the first straight section, the first corner section and the second straight section surround at least part of the first winding starting end
  • the insulating member includes a first section, a second section and a third section sequentially arranged along the winding direction of the second pole piece, the first section is arranged between the first straight section and the first diaphragm
  • the second section is arranged between the first corner section and the first winding starting end
  • the third section is arranged between the second straight section and the second diaphragm.
  • the insulating member can cover the first winding starting end from multiple angles and multiple orientations, and is not only arranged between the innermost circle of the second pole piece and the first winding starting end in the thickness direction of the electrode assembly, but also arranged between the innermost circle of the second pole piece and the first winding starting end in the length direction of the electrode assembly.
  • the innermost circle of the second pole piece is isolated from the first winding starting end to the greatest extent, and the short circuit phenomenon caused by the contact between the innermost circle of the second pole piece and the first winding starting end is alleviated.
  • the insulating member includes a first insulating member connected to the first diaphragm and the second diaphragm.
  • the first insulating member includes a first substrate layer and a first colloid layer, and the first substrate layer is connected to the first diaphragm and the second diaphragm through the first colloid layer.
  • the first substrate layer can ensure the insulation of the insulating member and have a certain strength
  • the second colloid layer can ensure that the insulating member is bonded to the first diaphragm and the second diaphragm.
  • the first colloid layer and the second colloid layer can also have insulating properties, and the embodiments of the present application are not limited to this.
  • the thickness of the first substrate layer is 5 mm to 50 mm, which not only ensures that the first substrate layer can prevent the positive and negative electrode sheets from short-circuiting, but also alleviates the problem of the first corner section being broken due to the thicker first substrate layer being arranged between the first corner section and the first winding start end.
  • the overlap length of the first colloid layer and the first diaphragm or the second diaphragm in the winding direction is 0.5 mm to 15 mm, which ensures that the first colloid layer and the first diaphragm have sufficient adhesion, while also preventing the problem of material waste caused by excessive overlap length between the first colloid layer and the first diaphragm in the winding direction.
  • the bonding strength of the first colloid layer is not less than 0.05 N/mm.
  • the first colloid layer needs to have sufficient bonding strength to ensure that after the electrode assembly is immersed in the electrolyte, the first colloid layer can still be bonded and fixed to the first diaphragm and the second diaphragm.
  • the thickness of the first colloid layer is 2 ⁇ m-20 ⁇ m, which ensures that the first colloid layer can be firmly bonded to the first diaphragm and the second diaphragm, and also alleviates the problem of material waste caused by the thick first colloid layer.
  • the first substrate layer is constructed as a PP material layer, a PI material layer or a PET material layer.
  • the flexibility of the PET material layer is not as good as that of the PP material layer or the PI material layer.
  • the PP material layer and the PI material layer have better flexibility, and the rebound force of the substrate after bending is low.
  • the insulating member further includes: a second insulating member, the second insulating member being connected to the inner surface of the innermost circle of the second pole piece.
  • the second insulating member can reduce the probability of positive and negative short circuits due to the contact between the first winding start end and the innermost circle of the second pole piece, and on the other hand, the first insulating member can also effectively prevent the positive ions of the second pole piece from escaping from the side of the first winding start end, thereby reducing the problem of metal precipitation at the first winding start end.
  • the second insulating member includes: a second colloid layer, the second colloid layer is connected to the inner surface of the innermost circle of the second pole piece.
  • the second colloid layer can be constructed as an insulating component to reduce the probability of positive and negative short circuits due to the contact between the first winding start end and the innermost circle of the second pole piece.
  • the second colloid layer can also effectively prevent the positive ions of the second pole piece from escaping from the side of the first winding start end, thereby reducing the problem of metal precipitation on the first winding start end.
  • the thickness of the second colloid layer is 2 ⁇ m-20 ⁇ m, which ensures that the second colloid layer can prevent the positive ions in the first corner segment from escaping and also alleviates the problem of the first corner segment being broken due to the second colloid layer being arranged on the inner side of the first corner segment.
  • the bonding strength of the second colloid layer in the electrolyte is 0.02N/mm-0.4N/mm.
  • the second colloid layer needs to have sufficient bonding strength to ensure that after the electrode assembly is immersed in the electrolyte, the second colloid layer can still be bonded and fixed to the inner surface of the innermost circle of the second electrode sheet.
  • the second gelatin layer is separated from the first substrate layer or the second gelatin layer is dissolved in the electrolyte.
  • the inner surface of the innermost circle of the second pole piece is only bonded with the second gelatin layer or is not bonded with any components at all, thereby alleviating the problem of the innermost circle of the second pole piece being broken due to excessive elastic force.
  • the second gelatin layer is separated from the first substrate layer
  • the first substrate layer includes a first side surface connected to the second gelatin layer and a second side surface connected to the first gelatin layer, and the roughness of the first side surface is less than the roughness of the second side surface. Since the roughness of the first side surface is less than the roughness of the second side surface, the bonding force between the second gelatin layer and the first side surface is less than the bonding force between the second side surface and the first gelatin layer, so that after the electrode assembly is immersed in the electrolyte, the second gelatin layer is more easily separated from the first substrate layer.
  • the second insulating member further includes: a second substrate layer, the second substrate layer being connected to the inner surface of the innermost circle of the second pole piece through the second colloid layer.
  • the inner surface of the first corner section is attached with the second colloid layer and the second substrate layer, which effectively prevents positive ions from escaping
  • the first winding start end is coated with the first diaphragm, the second diaphragm and the stacked first colloid layer and the first substrate layer, which can effectively alleviate the technical problem of positive and negative pole piece short circuit caused by the first winding start end protruding from the second winding start end.
  • the elongation of the second substrate layer is greater than that of the second pole piece, thereby reducing the force applied by the bent portion of the second substrate layer to the innermost circle of the second pole piece, thereby alleviating the probability of fracture of the innermost circle of the second pole piece.
  • the elongation of the second substrate layer is A
  • the elongation of the first substrate layer is B
  • A is greater than B.
  • the elongation of the second substrate layer is greater than that of the first substrate layer, so that the second substrate layer does not exert excessive elastic force on the first corner segment, thereby alleviating the problem that the first corner segment is prone to deformation.
  • the problem of breakage occurs, and the first substrate layer can better press the first diaphragm and the second diaphragm together, reducing the technical problem of the first substrate layer being separated from the first diaphragm and the second diaphragm due to vibration or drop tests.
  • a third gelatin layer is further provided between the first insulating member and the second insulating member, and after the electrode assembly is immersed in the electrolyte, the third gelatin layer dissolves in the electrolyte to separate the first insulating member from the second insulating member. Since the inner side surface of the innermost circle of the second electrode sheet and the first winding starting end are both provided with insulating components, the probability of short circuit of the positive and negative electrode sheets caused by the protrusion of the first winding starting end from the second winding starting end is further reduced.
  • the third glue layer is an acrylic glue layer or a rubber layer.
  • a void zone without active material is provided on the side of the second pole piece facing the first winding starting end, and the void zone is suitable for at least partially accommodating the insulating member.
  • the first electrode sheet is a negative electrode sheet
  • the second electrode sheet is a positive electrode sheet
  • an embodiment of the present application provides a battery cell, comprising the electrode assembly of the above embodiment.
  • an embodiment of the present application provides an electrical device, characterized in that it includes the battery cell of the above embodiment.
  • FIG1 is a schematic diagram of an electrode assembly provided by one embodiment of the present application.
  • FIG2 is a partial enlarged schematic diagram of the circle A in FIG1 ;
  • FIG3 is a schematic diagram of an insulating member provided by an embodiment of the present application.
  • FIG4 is a schematic diagram of an insulating member provided by an embodiment of the present application after being immersed in an electrolyte
  • FIG5 is a schematic diagram of an insulating member provided in another embodiment of the present application.
  • FIG6 is a schematic diagram of an insulating member immersed in an electrolyte according to another embodiment of the present application.
  • FIG7 is a schematic diagram of an insulating member immersed in an electrolyte provided by another embodiment of the present application.
  • FIG8 is a schematic diagram of an electrode assembly provided in another embodiment of the present application.
  • Icon Electrode assembly 100, A first pole piece 110, a first winding start end 111, The second pole piece 120, the first corner section 121, the first straight section 122, the second straight section 123, diaphragm 130, second winding start end 131, first diaphragm 132, second diaphragm 133, Insulation 140, first section a, second section b, third section c, first insulation e, second insulation d, The first base material layer 141b, the second base material layer 141a, the third glue layer 141c, the second glue layer 142, the first glue layer 143, The first side surface 101 , the second side surface 102 , the air avoidance area 103 , the thickness direction X of the electrode assembly, and the length direction Y of the electrode assembly.
  • the terms “installed”, “connected”, “connected”, and “attached” should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements.
  • installed should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements.
  • a and/or B can represent: A exists alone, A and B exist at the same time, and B exists alone.
  • the character "/" in this application generally indicates that the associated objects before and after are in an "or" relationship.
  • multiple refers to more than two (including two).
  • multiple groups refers to more than two groups (including two groups)
  • multiple sheets refers to more than two sheets (including two sheets).
  • the existing MMT Mod-Mid-Tab, the positive electrode tab is set in the middle of the positive electrode sheet, and the negative electrode tab is set in the middle of the negative electrode tab
  • structure generally adopts a winding needle to clamp the diaphragm for winding, resulting in four layers of diaphragm in the innermost circle and the thickness of the battery cell is increased, which leads to the problem of energy density loss in the thickness direction of the battery cell.
  • the pole piece includes: a pole piece starting section, which is located in the winding direction of the pole piece.
  • the inner part of the pole piece is located on the upper part;
  • the diaphragm includes: a diaphragm starting section, and the diaphragm starting section is located on the inner part of the diaphragm in the winding direction of the diaphragm.
  • the process of flat cutting of the pole piece and the diaphragm can be: the starting end of the pole piece starting section is flush with the starting end of the diaphragm starting section, so that the inner circle of the electrode assembly will not have a multi-layer diaphragm without covering the pole piece, and the problem of energy density loss of the electrode assembly in the thickness direction due to the multi-layer diaphragm of the inner circle is improved.
  • the starting end of the pole piece starting section since the starting end of the pole piece starting section is flush with the starting end of the diaphragm starting section, the starting end of the diaphragm starting section does not exceed the starting end of the pole piece starting section, or the distance between the starting end of the diaphragm starting section and the starting end of the pole piece starting section is small, after the battery cell roller or drop test, the diaphragm will shrink and cause the starting end of the pole piece starting section to extend out from the diaphragm starting section, so that the starting end of the pole piece starting section will be exposed, which may easily lead to the problem of two pole pieces with opposite polarities contacting and short-circuiting.
  • an embodiment of the present application proposes an electrode assembly 100, which can not only solve the problem of increased thickness of the battery cell due to the presence of multiple layers of diaphragms in the innermost circle of the electrode assembly, but also alleviate the problem of exposed pole pieces due to shrinkage of the diaphragms, which in turn causes two pole pieces with opposite polarities to contact and short-circuit.
  • the electrode assembly 100 is constructed as a wound structure, which is wound by a fixed winding needle.
  • the stripped first electrode sheet 110, the diaphragm 130, and the second electrode sheet 120 are sequentially wound and extruded into a cylindrical, elliptical, or square shape, and then placed in a suitable casing. Parameters such as the size of the electrode sheet and the number of winding turns are determined according to the design capacity of the battery.
  • the electrode assembly 100 includes: a first pole piece 110, a second pole piece 120 and a diaphragm 130, wherein the diaphragm 130 is disposed between the first pole piece 110 and the second pole piece 120, wherein the first pole piece 110 and the second pole piece 120 are pole pieces with opposite polarities, wherein one of the first pole piece 110 and the second pole piece 120 is a positive pole piece, and the other of the first pole piece 110 and the second pole piece 120 is a negative pole piece.
  • active ions such as lithium ions
  • the diaphragm 130 is disposed between the first pole piece 110 and the second pole piece 120, and can prevent the first pole piece 110 and the second pole piece 120 from short-circuiting, while allowing active ions to pass through.
  • the positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.
  • the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.
  • the present application has no particular limitation on the type of the separator 130, and any known porous structure separator 130 with good chemical stability and mechanical stability may be selected.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • the metal foil aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc.
  • the composite current collector may include a polymer material base and a metal layer.
  • the composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).
  • the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds.
  • the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used.
  • the negative electrode active material may be a negative electrode active material for a battery known in the art.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate.
  • the silicon-based material may be selected from elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen
  • the tin-based material may be selected from at least one of a single substance tin, a tin oxide compound, and a tin alloy.
  • the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the main material of the separator 130 can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic.
  • the separator 130 can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator 130 is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.
  • the separator 130 can be a separate component located between the positive and negative electrodes, or it can be attached to the surface of the positive and negative electrodes.
  • the separator 130 is a solid electrolyte, which is disposed between the positive electrode and the negative electrode, and plays the role of transmitting ions and isolating the positive and negative electrodes.
  • the first pole piece 110 includes a first winding start end 111
  • the separator 130 includes a second winding start end 131.
  • the first winding start end 111 is the end of the first pole piece 110 that is first rolled
  • the second winding start end 131 is the end of the separator 130 that is first rolled.
  • the first pole piece 110 and the separator 130 are cut flat, so the first winding start end 111 and the second winding start end 131 are flush.
  • the flush in the embodiment of the present application means that the distance between the first winding start end 111 and the second winding start end 131 does not exceed 5 mm.
  • the first winding start end 111 may extend beyond the second winding start end 131 by no more than 5 mm, or the first winding start end 111 may be completely flush with the second winding start end 131, or the second winding start end 131 may extend beyond the first winding start end 111 by no more than 5 mm.
  • the electrode assembly 100 further includes an insulating member 140 , which is disposed between the innermost circle of the second pole piece 120 and the first winding start end 111 to separate the first winding start end 111 from the second pole piece 120 .
  • the insulating member 140 may be made of a non-conductive material, for example, the insulating member 140 may be a plastic member, a rubber member, etc.
  • the insulating member 140 is disposed between the innermost circle of the second pole piece 120 and the first winding starting end 111, which means that the insulating member 140 may be disposed on the side of the innermost circle of the second pole piece 120 facing the first winding starting end 111, the insulating member 140 may also be disposed on the first winding starting end 111, or the insulating member 140 may be disposed in the gap separating the innermost circle of the second pole piece 120 and the first winding starting end 111.
  • the insulating member 140 is disposed on the diaphragm 130 on the first winding starting end 111, it can also be considered that the insulating member 140 is disposed on the first winding starting end 111.
  • the diaphragm 130 shrinks, and the first winding starting end 111 and the second winding starting end 131 that were originally flush with each other are no longer flush or the distance between them becomes larger, so that the first winding starting end 111 is exposed from between the two layers of the diaphragm 130. Due to the insulating member 140 arranged between the first winding starting end 111 and the innermost circle of the second pole piece 120, the first winding starting end 111 will not contact the second pole piece 120 to cause a short circuit.
  • the innermost circle of the second pole piece 120 includes a first corner segment 121, the first corner segment 121 is arranged opposite to the first winding starting end 111, and at least a portion of the insulating member 140 is arranged between the first corner segment 121 and the first winding starting end 111.
  • the first corner segment 121 may be the first corner segment of the innermost circle of the second pole piece 120 in the winding direction.
  • the first corner segment 121 may only include an arc segment.
  • the first corner segment 121 may also include an arc segment and straight segments connected at both ends of the arc segment.
  • the embodiment of the present application does not limit the specific structure of the first corner segment 121, as long as the first corner segment 121 is arranged near the first winding starting end 111.
  • the first corner segment 121 is disposed opposite to the first winding start end 111, and the first corner segment 121 may be disposed near the first winding start end 111, and the first corner segment 121 may be opposite to the first winding start end 111 in the length direction Y of the electrode assembly 100.
  • a portion of the first corner segment 121 may be opposite to the first winding start end 111 in the length direction Y of the electrode assembly 100, and another portion of the first corner segment 121 may also be opposite to the first winding start end 111 in the thickness direction X of the electrode assembly 100.
  • At least a part of the insulating member 140 is arranged between the first corner section 121 and the first winding starting end 111. That is to say, at least a part of the insulating member 140 can be arranged on the area of the first corner section 121 facing the first winding starting end 111, at least a part of the insulating member 140 can also be arranged on the area of the first winding starting end 111 facing the first corner section 121, and of course at least a part of the insulating member 140 can also be arranged in the gap between the first corner section 121 and the first winding starting end 111, as long as at least a part of the insulating member 140 is arranged between the first corner section 121 and the first winding starting end 111.
  • a portion of the insulating member 140 may be disposed between the first corner segment 121 and the first winding starting end 111 in the length direction Y of the electrode assembly 100, and a portion of the insulating member 140 may also be disposed between the first corner segment 121 and the first winding starting end 111 in the length direction Y of the electrode assembly 100.
  • a portion of the insulating member 140 can be disposed on an area where the first corner segment 121 faces the first winding starting end 111 in the length direction Y of the electrode assembly 100, and a portion of the insulating member 140 can also be disposed on an area where the first winding starting end 111 faces the first corner segment 121 in the length direction Y of the electrode assembly 100.
  • the insulating member 140 may not prevent the diaphragm 130 from shrinking, but prevent the first winding start end 111 from contacting the first corner section 121 by being disposed between the first winding start end 111 and the first corner section 121.
  • the diaphragm 130 includes a first diaphragm 132 and a second diaphragm 133 located on both sides of the first pole piece 110. It should be noted that the two sides of the first pole piece 110 refer to the two sides of the first pole piece 110 in the thickness direction.
  • the insulating member 140 is wound around the first winding start end 111, and the two ends of the insulating member 140 are respectively connected to the first diaphragm 132 and the second diaphragm 133.
  • the first winding start end 111 has an end surface
  • the insulating member 140 is wound around the end surface of the first winding start end 111 and is respectively connected to the first diaphragm 132 and the second diaphragm 133 after being bent.
  • the insulating member 140 can be constructed as a "C"-shaped structure, and after the insulating member 140 is connected to the first diaphragm 132 and the second diaphragm 133, the insulating member 140 can wrap the end surface of the first winding start end 111.
  • the insulating member 140 bypasses the first winding starting end 111 and is connected to the first diaphragm 132 and the second diaphragm 133 respectively, the contraction of the diaphragm 130 can be restricted, and the first winding starting end 111 is effectively relieved from the second winding starting end 111.
  • the innermost circle of the second pole piece 120 further includes a first straight section 122 and a second straight section 123, the first corner section 121 is connected between the first straight section 122 and the second straight section 123, and the first straight section 122, the first corner section 121, and the second straight section 123 surround at least a portion of the first winding start end 111.
  • the first straight section 122, the first corner section 121, and the second straight section 123 can be arranged sequentially along the winding direction of the second pole piece 120.
  • the first corner section 121 may be configured as an arc section, the first straight section 122 and the second straight section 123 may be arranged at both ends of the arc section and may not be bent and configured as two straight sections, and the first straight section 122, the first corner section 121 and the second straight section 123 may be configured as a "C"-shaped structure.
  • the first straight section 122, the first corner section 121 and the second straight section 123 of the "C"-shaped structure surround at least a portion of the first winding start end 111.
  • the insulating member 140 includes a first section a, a second section b and a third section c which are sequentially arranged along the winding direction of the first pole piece 110.
  • the first section a is arranged between the first straight section 122 and the first diaphragm 132
  • the second section b is arranged between the first corner section 121 and the first winding starting end 111
  • the third section c is arranged between the second straight section 123 and the second diaphragm 133.
  • the first section a, the second section b and the third section c can be constructed as a "C" shaped structure, that is, the shape of the insulating member 140 can be roughly the same as the shape of the first corner section 121, so that the insulating member 140 can better cover the first winding starting end 111, thereby effectively alleviating the short circuit problem caused by the contact between the first winding starting end 111 and the innermost circle of the second pole piece 120.
  • the first section a is arranged between the first straight section 122 and the first diaphragm 132, that is, the first section a, the first straight section 122 and the first diaphragm 132 are opposite to each other in the thickness direction X of the electrode assembly 100;
  • the second section b is arranged between the first corner section 121 and the first winding starting end 111, that is, the end faces of the second section b, the first corner section 121 and the first winding starting end 111 are opposite to each other in the length direction Y of the electrode assembly 100
  • the third section c is arranged between the second straight section 123 and the second diaphragm 133, that is, the third section c, the second straight section 123 and the second diaphragm 133 are opposite to each other in the thickness direction X of the electrode assembly 100.
  • the insulating member 140 can cover the first winding start end 111 from multiple angles and multiple orientations, and is not only disposed between the innermost circle of the second pole piece 120 and the first winding start end 111 in the thickness direction X of the electrode assembly 100, but also disposed between the innermost circle of the second pole piece 120 and the first winding start end 111 in the length direction Y of the electrode assembly 100.
  • the innermost circle of the second pole piece 120 is isolated from the first winding start end 111 to the greatest extent, and the short circuit phenomenon caused by the contact between the innermost circle of the second pole piece 120 and the first winding start end 111 is alleviated.
  • the insulating member 140 includes a first insulating member e, and the first insulating member e is connected to the first diaphragm 132 and the second diaphragm 133.
  • the first insulating member e can cover the first winding start end 111, thereby reducing the probability of positive and negative electrode sheets contacting and short-circuiting due to the first winding start end 111 protruding from the second winding start end 131.
  • the first insulating member e may include a first substrate layer 141b and a first colloid layer 143, and the first substrate layer 141b is connected to the first separator 132 and the second separator 133 through the first colloid layer 143.
  • the first substrate layer 141b may be connected to the inner surface of the innermost circle of the second electrode sheet 120 through the second colloid layer 142.
  • the first substrate layer 141b can ensure the insulation of the insulating member 140 and have a certain strength.
  • the gelatin layer 143 can ensure that the first substrate layer 141b is bonded to the first diaphragm 132 and the second diaphragm 133.
  • the first gelatin layer 143 can also have an insulating property, which is not limited in the embodiment of the present application.
  • the thickness t2 of the first substrate layer 141b may be 5 mm to 50 mm.
  • the thickness t2 of the first substrate layer 141b directly determines whether the second pole piece 120 is smooth during the winding process. The greater the thickness t2 of the first substrate layer 141b, the greater the difficulty of bending the first corner section 121 of the second pole piece 120 during the winding process. The smaller the thickness t2 of the first substrate layer 141b, the less difficult it is to bend the first corner section 121 of the second pole piece 120 during the winding process. Moreover, the thicker first substrate layer 141b will also apply a greater elastic force to the first corner section 121 after bending, so that the first corner section 121 is prone to breakage.
  • the thickness t2 of the first substrate layer 141b is limited to 5 ⁇ m-50 ⁇ m. This ensures that the first substrate layer 141b can prevent the positive and negative electrodes from short-circuiting, and also alleviates the problem of the first corner section 121 breaking during the winding process of the electrode assembly 100 due to the thicker first substrate layer 141b being arranged between the first corner section 121 and the first winding start end 111.
  • the thickness t2 of the first substrate layer 141b can be 5 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 25 ⁇ m, 30 ⁇ m, 35 ⁇ m, 40 ⁇ m, 45 ⁇ m or 50 ⁇ m.
  • the embodiment of the present application does not specifically limit the thickness t2 of the first substrate layer 141b, as long as the thickness of the first substrate layer 141b falls within the above range.
  • an overlapping length L1 between the first colloid layer 143 and the first diaphragm 132 or the second diaphragm 133 in the winding direction is 0.5 mm to 15 mm.
  • the first colloid layer 143 and the first diaphragm 132 can be bonded and fixed, and the area of the bonding region between the first colloid layer 143 and the first diaphragm 132 directly affects the bonding force between the first colloid layer 143 and the first diaphragm 132, and the overlapping length of the first colloid layer 143 and the first diaphragm 132 in the winding direction directly determines the area of the bonding region between the first colloid layer 143 and the first diaphragm 132.
  • the overlapping length of the first gelatin layer 143 and the first diaphragm 132 or the second diaphragm 133 in the winding direction is set to 0.5mm-15mm, which ensures that there is sufficient adhesion between the first gelatin layer 143 and the first diaphragm 132, and at the same time avoids the problem of material waste due to excessive overlapping length between the first gelatin layer 143 and the first diaphragm 132 in the winding direction.
  • the first colloid layer 143 and the second diaphragm 133 can be bonded and fixed, and the area of the bonding region between the first colloid layer 143 and the second diaphragm 133 directly affects the bonding force between the first colloid layer 143 and the second diaphragm 133, and the overlapping length of the first colloid layer 143 and the second diaphragm 133 in the winding direction directly determines the area of the bonding region between the first colloid layer 143 and the second diaphragm 133.
  • the overlapping length of the first colloid layer 143 and the first diaphragm 132 or the second diaphragm 133 in the winding direction is set to 0.5mm-15mm, which not only ensures that there is sufficient adhesion between the first colloid layer 143 and the second diaphragm 133, but also prevents the first colloid layer 143 and the second diaphragm 133 from overlapping in the winding direction.
  • the bonding strength of the first gelatin layer 143 is not less than 0.05 N/mm.
  • the first gelatin layer 143 needs to have sufficient bonding strength to ensure that the first gelatin layer 143 can still be bonded and fixed to the first diaphragm 132 and the second diaphragm 133 after the electrode assembly 100 is immersed in the electrolyte.
  • the bonding strength of the first gelatin layer 143 can be 0.05 N/mm, 0.1 N/mm, 0.15 N/mm, 0.2 N/mm, 0.25 N/mm, 0.3 N/mm, etc.
  • the embodiment of the present application does not limit the bonding strength of the first gelatin layer 143 in the electrolyte, as long as the bonding strength of the first gelatin layer 143 in the electrolyte is within the above range.
  • the thickness t3 of the first colloid layer 143 is 2 ⁇ m-20 ⁇ m.
  • the thickness t3 of the first colloid layer 143 directly determines the adhesion between the first colloid layer 143 and the first diaphragm 132 and the second diaphragm 133.
  • the greater the thickness t3 of the first colloid layer 143 the greater the adhesion between the first colloid layer 143 and the first diaphragm 132 and the second diaphragm 133.
  • the smaller the thickness t3 of the first colloid layer 143 the smaller the adhesion between the first colloid layer 143 and the first diaphragm 132 and the second diaphragm 133.
  • the thickness t3 of the first gelatin layer 143 is limited to 2 ⁇ m-20 ⁇ m, which ensures that the first gelatin layer 143 can be firmly bonded to the first diaphragm 132 and the second diaphragm 133 , and also alleviates the problem of material waste caused by the thick first gelatin layer 143 .
  • the thickness t3 of the first gelatin layer 143 may be 2 ⁇ m, 5 ⁇ m, 8 ⁇ m, 11 ⁇ m, 14 ⁇ m, 17 ⁇ m or 20 ⁇ m.
  • the embodiment of the present application does not specifically limit the thickness t3 of the first gelatin layer 143 as long as the thickness of the first gelatin layer 143 falls within the above range.
  • the insulating member only includes a first insulating member e, and the first insulating member e is connected to the first diaphragm 132 and the second diaphragm 133.
  • first insulating member e is provided between the innermost circle of the second pole piece 120 and the first winding starting end 111, and the first insulating member e is only connected to the first diaphragm 132 and the second diaphragm 133, and no insulating member is attached to the inner side surface of the innermost circle of the second pole piece 120, so that the inner side surface of the innermost circle of the second pole piece 120 is no longer subjected to the elastic force generated by the bending of the insulating member, which greatly reduces the probability of the innermost circle of the second pole piece 120 being broken.
  • the first insulating member e Before the battery cell is injected with liquid, the first insulating member e can be connected to the inner side surface of the innermost circle of the second electrode piece 120 through the gelatin layer. After the injection is completed, the electrode assembly 100 is immersed in the electrolyte. At this time, the gelatin layer on the inner side surface of the innermost circle of the second electrode piece 120 is dissolved in the electrolyte, and the first insulating member e is separated from the innermost circle of the second electrode piece 120.
  • the first insulating member e is connected to the first diaphragm 132 and the second diaphragm 133, thereby alleviating the short circuit phenomenon of the positive and negative electrode sheets caused by the first winding starting end 111 protruding out of the second winding starting end 131 due to the shrinkage of the diaphragm 130.
  • the first insulating member e before the battery cell is filled with liquid, can be connected to the inner side surface of the innermost circle of the second electrode piece 120 through a gelatinous layer. After the filling is completed, the electrode assembly 100 is immersed in the electrolyte. At this time, the gelatinous layer on the inner side surface of the innermost circle of the second electrode piece 120 is not only separated from the first insulating member e, but also separated from the innermost circle of the second electrode piece 120, so that the first insulating member e is separated from the innermost circle of the second electrode piece 120.
  • the first insulating member e may include a first substrate layer 141b and a first colloid layer 143.
  • the specific connection method and effect are as described above and will not be repeated here.
  • the first insulating member e may also be constructed as a colloid layer only.
  • the first insulating member e has not only insulating properties but also adhesive properties.
  • the first insulating member e may be bonded to the first diaphragm 132 and the second diaphragm 133. This can not only reduce the The possibility of positive and negative short circuits occurring when the winding starting end 111 contacts the innermost circle of the second pole piece 120 also reduces the energy density loss of the electrode assembly 100 in the thickness direction to a certain extent.
  • the insulating member further includes a second insulating member d, and the second insulating member d is connected to the inner surface of the innermost circle of the second pole piece 120.
  • the second insulating member d can reduce the probability of positive and negative short circuits due to the contact between the first winding starting end 111 and the innermost circle of the second pole piece 120, and on the other hand, the first insulating member d can also effectively prevent the positive ions of the second pole piece 120 from escaping toward the side of the first winding starting end 111, thereby reducing the problem of metal precipitation on the first winding starting end 111.
  • the second insulating member d includes a second colloid layer 142, and the second colloid layer 142 is connected to the inner surface of the innermost circle of the second pole piece 120.
  • the second colloid layer 142 can be bonded and fixed to the inner surface of the innermost circle of the second pole piece 120, and the second colloid layer 142 can be constructed as an insulating component to reduce the probability of positive and negative short circuits due to the contact between the first winding starting end 111 and the innermost circle of the second pole piece 120.
  • the second colloid layer 142 can also effectively prevent the positive ions of the second pole piece 120 from escaping toward the side of the first winding starting end 111, thereby reducing the problem of metal precipitation on the first winding starting end 111.
  • the first substrate layer 141b when the electrode assembly 100 is not immersed in the electrolyte, can be connected to the inner surface of the innermost circle of the second electrode plate 120 through the second gel layer 142. After the electrode assembly 100 is immersed in the electrolyte, the first substrate layer 141b can be detached from the second electrode plate 120.
  • the inner surface of the innermost circle of the second electrode plate 120 will not always be attached with the entire first substrate layer 141b, thereby reducing the probability of the first corner segment 121 being easily broken due to the elastic force of the first substrate layer 141b after bending.
  • the first substrate layer 141b is firstly bonded to the second electrode sheet 120 through the second gelatin layer 142.
  • the first gelatin layer 143 on the first substrate layer 141b is not bonded to the first diaphragm 132 and the second diaphragm 133; then, during the winding process, a part of the innermost circle on the second electrode sheet 120 is bent, so that a part of the innermost circle of the second electrode sheet 120 forms a first corner segment 121, and at the same time, the first substrate layer 141b, the second gelatin layer 142 and the first gelatin layer 143 attached to the inner side surface of the first corner segment 121 are also bent, and then the first gelatin layer 143 is bonded to the first diaphragm 132 and the second diaphragm 133.
  • the elastic stress generated by the bending of the first substrate layer 141b will be applied to the inner side of the first corner segment 121, thereby causing the first corner segment 121 to break.
  • the second gelatin layer 142 is separated from the first insulating member e (for example, the first substrate layer 141b). That is, the bonding force between the second gelatin layer 142 and the first substrate layer 141b is lower than the bonding force between the first gelatin layer 143 and the first substrate layer 141b.
  • the second gelatin layer 142 is more easily separated from the first substrate layer 141b, while the first substrate layer 141b is bonded to the first gelatin layer 143, and the first substrate layer 141b is bonded to the first diaphragm 132 and the second diaphragm 133 through the first gelatin layer 143.
  • the surface of the first substrate layer 141b bonded to the second colloid layer 142 and the surface of the first substrate layer 141b bonded to the first colloid layer 143 can be treated by corona treatment. After the first substrate layer 141 b is subjected to the corona treatment, the first adhesive layer 143 is more firmly bonded to the first substrate layer 141 b than the second adhesive layer 142 .
  • the first substrate layer 141b includes a first side surface 101 connected to the second gelatin layer 142 and a second side surface 102 connected to the first gelatin layer 143, and the roughness of the first side surface 101 is less than the roughness of the second side surface 102.
  • the roughness of the surface is proportional to the adhesive force of the gelatin layer on the surface, that is, the greater the roughness of the surface, the greater the adhesive force between the gelatin layer and the surface after the gelatin layer is bonded to the surface; the smaller the roughness of the surface, the smaller the adhesive force between the gelatin layer and the surface after the gelatin layer is bonded to the surface.
  • the adhesion between the second gelatin layer 142 and the first side 101 is smaller than the adhesion between the second side 102 and the first gelatin layer 143, so that after the electrode assembly 100 is immersed in the electrolyte, the second gelatin layer 142 is more easily separated from the first substrate layer 141b.
  • the roughness of the first side surface 101 and the roughness of the second side surface 102 can be achieved by corona treatment, and of course can also be achieved by other methods.
  • the embodiment of the present application does not limit the formation method of the roughness of the first side surface 101 and the roughness of the second side surface 102.
  • the second gelatin layer 142 dissolves in the electrolyte.
  • the inner surface of the innermost circle of the second pole piece 120 is completely not bonded to any component, thereby alleviating the problem of fracture caused by the elastic force generated by the bending of the second gelatin layer 142 and applied to the innermost circle of the second pole piece 120.
  • first winding starting end 111 is covered by the first diaphragm 132, the second diaphragm 133, and the stacked first substrate layer 141b and the first gelatin layer 143, there is no exposed current collector exposed on the first winding starting end 111, so even if the inner surface of the innermost circle of the second pole piece 120 is not bonded with the second gelatin layer 142, there will still be no problem of positive ion precipitation on the first winding starting end 111.
  • the thickness t1 of the second colloid layer 142 is 2 ⁇ m-20 ⁇ m.
  • the thickness of the second colloid layer 142 directly determines whether the second pole piece 120 is smooth during the winding process. The greater the thickness of the second colloid layer 142, the greater the difficulty of bending the first corner section 121 of the second pole piece 120 during the winding process. The smaller the thickness of the second colloid layer 142, the smaller the difficulty of bending the first corner section 121 of the second pole piece 120 during the winding process. Moreover, the thicker second colloid layer 142 will also apply a greater elastic force to the first corner section 121 after bending, so that the first corner section 121 is prone to breakage.
  • the thickness t1 of the second gelatin layer 142 is limited to 2 ⁇ m-20 ⁇ m, which ensures that the second gelatin layer 142 can prevent the positive ions in the first corner segment 121 from escaping, and also alleviates the problem of the first corner segment 121 being broken due to the second gelatin layer 142 being arranged on the inner side of the first corner segment 121.
  • the thickness t1 of the second gelatin layer 142 may be 2 ⁇ m, 5 ⁇ m, 8 ⁇ m, 11 ⁇ m, 14 ⁇ m, 17 ⁇ m or 20 ⁇ m.
  • the embodiment of the present application does not specifically limit the thickness t1 of the second gelatin layer 142 as long as the thickness of the second gelatin layer 142 falls within the above range.
  • the bonding strength of the second colloid layer 142 in the electrolyte is 0.02N/mm-0.4N/mm.
  • the second colloid layer 142 needs to have sufficient bonding strength to ensure that the second colloid layer 142 can still be bonded and fixed to the inner surface of the innermost circle of the second electrode sheet 120 after the electrode assembly 100 is immersed in the electrolyte.
  • the bonding strength of the second colloid layer 142 in the electrolyte can be 0.02N/mm, 0.05N/mm, 0.1N/mm, 0.15N/mm, 0.2N/mm, 0.25N/mm, 0.3N/mm, 0.35N/mm or 0.4N/mm.
  • the present application embodiment does not limit the bonding strength of the second colloid layer 142 in the electrolyte. As long as the second colloid layer 142 is The bonding strength of the layer 142 in the electrolyte solution may be within the above range.
  • the second insulating member d further includes a second substrate layer 141a, and the second substrate layer 141a and the first substrate layer 141b can play an insulating role.
  • the second colloid layer 142 is disposed between the second substrate layer 141a and the inner side surface of the innermost circle of the second pole piece 120.
  • the second colloid layer 142 and the second substrate layer 141a are bonded to the inner surface of the innermost circle of the second electrode sheet 120, and the first colloid layer 143 and the first substrate layer 141b are bonded to the first diaphragm 132 and the second diaphragm 133. Therefore, on the one hand, the inner surface of the first corner section 121 is attached with the second colloid layer 142 and the second substrate layer 141a, which effectively prevents the positive ions from escaping.
  • the first winding starting end 111 is coated with the first diaphragm 132, the second diaphragm 133 and the stacked first colloid layer 143 and the first substrate layer 141b, which can effectively alleviate the technical problem of short circuit between the positive and negative electrodes caused by the first winding starting end 111 protruding from the second winding starting end 131.
  • the elongation of the second substrate layer 114a is greater than the elongation of the second pole piece 120, and thus the second substrate layer 114a is bonded to the inner side surface of the first corner segment 121 of the second pole piece 120 through the second glue layer 142.
  • the bent second substrate layer 114a will not exert excessive elastic force on the first corner segment 121 due to its larger elongation, thereby alleviating the problem of the first corner segment 121 being prone to breakage.
  • the elongation of the second substrate layer 114a is A
  • the elongation of the first substrate layer 114b is B
  • the elongation A of the second substrate layer 114a is greater than the elongation B of the first substrate layer 114b.
  • the force applied by the bent portion of the second substrate layer 114a to the innermost circle of the second pole piece 120 is reduced, thereby alleviating the probability of fracture of the innermost circle of the second pole piece 120. Since the first substrate layer 114b is bonded and fixed to the first diaphragm 132 and the second diaphragm 133 by the first colloid layer 143, there is no need to make too many requirements on the elongation of the first substrate layer 114b.
  • the elongation of the first substrate layer 114b cannot be too large, and it is best to be less than the elongation of the second substrate layer 114a, so that the first substrate layer 114b can better press the first diaphragm 132 and the second diaphragm 133, and reduce the technical problem of the first substrate layer 114b being separated from the first diaphragm 132 and the second diaphragm 133 due to vibration or drop test.
  • the elongation of the second substrate layer 114a is A
  • the elongation of the first substrate layer 114b is B
  • A is greater than B.
  • the elongation of the second substrate layer 114a is greater than the elongation of the first substrate layer 114b, so that the second substrate layer 114a does not apply too much elastic force to the first corner section 121, thereby alleviating the problem that the first corner section 121 is prone to breakage, and the first substrate layer 114b can better press the first diaphragm 132 and the second diaphragm 133, reducing the technical problem of the first substrate layer 114b being separated from the first diaphragm 132 and the second diaphragm 133 due to vibration or drop tests.
  • a third gelatin layer 141c is further provided between the first insulating member e and the second insulating member d. After the electrode assembly 100 is immersed in the electrolyte, the third gelatin layer 141c dissolves in the electrolyte to separate the first insulating member e from the second insulating member d.
  • insulating components are provided on the inner side surface of the innermost circle of the second electrode sheet 120 and the first winding starting end 111, thereby further reducing the probability of short circuit of the positive and negative electrode sheets caused by the first winding starting end 111 protruding from the second winding starting end 131.
  • the third gelatin layer 141c is an acrylic gelatin layer or a rubber layer.
  • the third gelatin layer 141c is configured as an acrylic gelatin layer or a rubber layer, and can be dissolved after the electrode assembly 100 is immersed in the electrolyte, so that after the electrode assembly 100 is immersed in the electrolyte, the third gelatin layer 141c is dissolved in the electrolyte to separate the second substrate layer 141a and the first substrate layer 141b.
  • the present application does not limit the specific type of the third gelatin layer 141c, as long as the third gelatin layer 141c is dissolved after the electrode assembly 100 is immersed in the electrolyte. Dissolve in electrolyte.
  • the third gelatin layer 141c is separated from the first insulating member e and the third gelatin layer 141c is also separated from the second insulating member d.
  • the first insulating member e includes a first substrate layer 141b and a first glue layer 143, and the first substrate layer 141b is bonded to the first diaphragm 142 and the second diaphragm 143 through the first glue layer 143;
  • the second insulating member d includes a second substrate layer 141a and a second glue layer 142, and the second substrate layer 141a is bonded to the inner side surface of the innermost circle of the second pole piece 120 through the second glue layer 142.
  • the side of the first substrate layer 141b facing away from the first gelatin layer 143 is bonded and fixed to the third gelatin layer 141c, and the side of the second substrate layer 141a facing away from the second gelatin layer 142 is bonded and fixed to the third gelatin layer 141c.
  • the third gelatin layer 141c is separated from the first substrate layer 141b and the third gelatin layer 141c is also separated from the second substrate layer 141a.
  • the surface of the second substrate layer 141a bonded to the third colloid layer 141c and the surface of the first substrate layer 141b bonded to the third colloid layer 141c can be treated by corona treatment, so that after the first substrate layer 141b and the second substrate layer 141a are treated by corona treatment and after the electrode assembly 100 is immersed in the electrolyte, the third colloid layer 141c can be easily separated from the second substrate layer 141a and the first substrate layer 141b.
  • the roughness of the surface of the second substrate layer 141a that is bonded to the third gelatin layer 141c can be set to be relatively small, so that the third gelatin layer 141c can be easily separated from the second substrate layer 141a after the electrode assembly 100 is immersed in the electrolyte.
  • the roughness of the surface of the first substrate layer 141b that is bonded to the third gelatin layer 141c can also be set to be relatively small, so that the third gelatin layer 141c can be easily separated from the first substrate layer 141b after the electrode assembly 100 is immersed in the electrolyte.
  • the roughness of the surface is proportional to the adhesion force of the gum layer on the surface, that is, the greater the roughness of the surface, the greater the adhesion force between the gum layer and the surface after the gum layer is adhered to the surface; the smaller the roughness of the surface, the smaller the adhesion force between the gum layer and the surface after the gum layer is adhered to the surface.
  • the roughness of the surface of the second substrate layer 141a bonded to the third colloid layer 141c may be the same as the roughness of the surface of the first substrate layer 141b bonded to the third colloid layer 141c.
  • the roughness of the surface of the second substrate layer 141a bonded to the third colloid layer 141c and the roughness of the surface of the first substrate layer 141b bonded to the third colloid layer 141c may be achieved by corona treatment, and of course, may also be achieved by other methods.
  • the embodiment of the present application does not limit the formation method of the roughness of the surface of the second substrate layer 141a bonded to the third colloid layer 141c and the roughness of the surface of the first substrate layer 141b bonded to the third colloid layer 141c.
  • the first substrate layer 141b is constructed as a PP (Polypropylene) material layer, a PI (Polyimide) material layer or a PET (Polyethylene terephthalate) material layer.
  • PP Polypropylene
  • PI Polyimide
  • PET Polyethylene terephthalate
  • the second substrate layer 141a can be a PP material layer or a PI material layer.
  • the PP material layer and the PI material layer have good flexibility and low rebound force after the substrate is bent. Therefore, when the second substrate layer 141a is bonded to the inner surface of the innermost circle of the second pole piece 120 through the second glue layer 142, the elastic force applied by the second substrate layer 141a on the first corner segment 121 is small, thereby effectively alleviating the problem of easy breakage of the first corner segment 121.
  • the first substrate layer 141b may be a PET material layer.
  • the flexibility of the PET material layer is not as good as that of the PP material layer. Or the flexibility of the PI material layer, so that the PET material layer can better press the first diaphragm 132 and the second diaphragm 133, reducing the technical problem of the first substrate layer 141b detaching from the first diaphragm 132 and the second diaphragm 133 due to vibration or drop tests.
  • a side of the second pole piece 120 facing the first winding starting end 111 is provided with an air-avoiding area 103, on which there is no active material, and the air-avoiding area 103 is suitable for at least partially accommodating the insulating member 140.
  • the insulating member 140 is provided between the innermost circle of the second pole piece 120 and the first winding starting end 111, at least part of the insulating member 140, such as the second colloid layer 142 of the insulating member 140, is bonded to the innermost circle of the second pole piece 120, or the second colloid layer 142 of the insulating member 140 and the second substrate layer 141a are bonded to the innermost circle of the second pole piece 120, the area of the innermost circle of the second pole piece 120 facing the first winding starting end 111 does not participate in the charge and discharge reaction because it is at least partially blocked by the insulating member 140.
  • an air avoidance area 103 with no active material is provided on the side of the second pole piece 120 facing the first winding starting end 111, so that at least a portion of the insulating member 140 can be accommodated in the air avoidance area 103, thereby reducing the thickness of the portion of the second pole piece 120 facing the first winding starting end 111, thereby improving the energy density of the battery cell.
  • the first electrode sheet 110 is a negative electrode sheet
  • the second electrode sheet 120 is a positive electrode sheet.
  • An insulating member 140 is provided between the winding start end of the negative electrode sheet and the innermost circle of the positive electrode sheet, so that even if the diaphragm 130 shrinks, the winding start end of the negative electrode sheet protrudes from the winding start end of the diaphragm 130, and the winding start end of the negative electrode sheet will not contact the positive electrode sheet, effectively alleviating the short circuit between the positive and negative electrode sheets.
  • the electrode assembly 100 in this embodiment is not immersed in the electrolyte.
  • the electrode assembly 100 includes: a first pole piece 110 and a second pole piece 120 with opposite polarities, and a separator 130 disposed between the first pole piece 110 and the second pole piece 120, the first pole piece 110 includes a first winding start end 111, the separator 130 includes a second winding start end 131, and the first winding start end 111 and the second winding start end 131 are substantially flush in the winding direction of the pole piece.
  • the electrode assembly 100 also includes an insulating member 140, which is disposed between the innermost circle of the second pole piece 120 and the first winding start end 111.
  • the diaphragm 130 includes a first diaphragm 132 and a second diaphragm 133 located on both sides of the first pole piece 110 .
  • the insulating member 140 is wound around the first winding start end 111 , and the insulating member 140 is connected to the first diaphragm 132 and the second diaphragm 133 , respectively.
  • the innermost circle of the second pole piece 120 includes a first corner segment 121 and a first straight segment 122 and a second straight segment 123 respectively connected to the two ends of the first corner segment 121, and the insulating member 140 includes a first segment a, a second segment b and a third segment c sequentially connected in the winding direction, the first segment a is arranged between the first straight segment 122 and the first diaphragm 132, the second segment b is arranged between the first corner segment 121 and the first winding starting end 111, and the third segment c is arranged between the second straight segment 123 and the second diaphragm 133.
  • the insulating member includes a first substrate layer 141b, a second colloid layer 142 and a first colloid layer 143, wherein the second colloid layer 142 is bonded to the innermost circle of the second pole piece 120, and the first substrate layer 141b is bonded to the first diaphragm 132 and the second diaphragm 133 through the first colloid layer 143.
  • the insulating member may also include a second substrate layer 141a, wherein the second substrate layer 141a is bonded to the innermost circle of the second pole piece 120 through the second colloid layer 142, and the first substrate layer 141b is bonded to the first diaphragm 132 and the second diaphragm 133 through the first colloid layer 143.
  • a free space without active material is provided on the side of the second pole piece 120 facing the first winding starting end 111.
  • the air-avoidance area 103 is suitable for at least partially accommodating the insulating member 140, the first pole piece 110 is a negative pole piece, and the second pole piece 120 is a positive pole piece.
  • the battery cell includes the electrode assembly 100 of the above embodiment. Since the battery cell according to the embodiment of the present application is provided with the above electrode assembly, the stability of the battery cell is significantly improved, and the probability of short circuit problems between the positive and negative electrodes is effectively reduced.
  • the electric device according to the embodiment of the present application includes the above-mentioned battery cell. Since the electric device according to the embodiment of the present application is provided with the above-mentioned battery cell, the electric device can alleviate the phenomenon of positive and negative electrode plates contacting and short-circuiting due to the contraction of the diaphragm 130 .
  • the electrical equipment may be, but is not limited to, mobile phones, tablet computers, laptop computers, electric toys, electric tools, electric bicycles, electric motorcycles, electric cars, ships, spacecraft, etc.
  • the electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.
  • the spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.

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Abstract

本申请实施例提供一种电极组件、电芯和用电设备，所述电极组件为卷绕式结构，所述电极组件包括第一极片、第二极片和隔膜，所述隔膜设置于所述第一极片和所述第二极片之间，所述第一极片包括第一卷绕起始端，所述隔膜包括第二卷绕起始端，沿所述电极组件的卷绕方向，所述第一卷绕起始端与所述第二卷绕起始端之间的距离不超过5mm；其中，所述电极组件还包括绝缘件，所述绝缘件设置于所述第二极片的最内圈和所述第一卷绕起始端之间，以将所述第一卷绕起始端和所述第二极片隔开。

Description

电极组件、电芯和用电设备
相关申请的交叉引用
本申请要求享有于2023年07月10日提交的名称为“电极组件、电芯和用电设备”的中国专利申请CN202310835195.0的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请涉及电池技术领域，具体而言，涉及一种电极组件、电芯和用电设备。
背景技术
电芯广泛应用于便携式电子设备、电动交通工具、电动工具、无人机、储能设备等领域。电芯的制造过程中，电芯的可靠性是一个不可忽视的问题。因此，如何提高电芯的可靠性，是电芯技术中一个亟需解决的技术问题。
发明内容
本申请提供一种电极组件、电芯和用电设备，该电极组件可以有效提升电芯的可靠性。
本申请是通过下述技术方案实现的：
第一方面，本申请实施例提供一种电极组件，电极组件为卷绕式结构，电极组件包括第一极片、第二极片和隔膜，隔膜设置于第一极片和第二极片之间，第一极片包括第一卷绕起始端，隔膜包括第二卷绕起始端，沿所述电极组件的卷绕方向，第一卷绕起始端与第二卷绕起始端之间的距离不超过5mm；其中，电极组件还包括绝缘件，绝缘件设置于第二极片的最内圈和第一卷绕起始端之间，以将第一卷绕起始端和第二极片隔开。
根据本申请实施例的电极组件，即使电芯摔落或者进行跌落测试后，隔膜发生收缩，原来彼此平齐的第一卷绕起始端和第二卷绕起始端不在平齐或者二者之间的距离变大，从而第一卷绕起始端从两层隔膜之间裸露出来，其也会由于设置在第一卷绕起始端和第二极片的最内圈之间的绝缘件，不会出现第一卷绕起始端与第二极片接触而发生短路现象。
根据本申请的一些实施例，第二极片的最内圈包括第一拐角段，第一拐角段与第一卷绕起始端相对设置，绝缘件的至少一部分设置于第一拐角段与第一卷绕起始端之间。由于绝缘件的至少一部分设置于第一拐角段与第一卷绕起始端之间，因此即使在隔膜发生收缩、第一卷绕起始端凸出于第二卷绕起始端，第一卷绕起始端也会被绝 缘件阻隔，而不会出现第一卷绕起始端与第一拐角段接触而导致正负极片短路的技术问题。
根据本申请的一些实施例，隔膜包括位于第一极片两侧的第一隔膜和第二隔膜；绝缘件绕过第一卷绕起始端，且绝缘件的两端分别与第一隔膜和第二隔膜连接。由于绝缘件绕过第一卷绕起始端且分别与第一隔膜和第二隔膜连接，从而可以限制隔膜发生收缩，有效缓解了第一卷绕起始端从第二卷绕起始端伸出的问题。
根据本申请的一些实施例，第二极片的最内圈包括第一平直段和第二平直段，第一拐角段连接第一平直段和第二平直段，第一平直段、第一拐角段和第二平直段环绕第一卷绕起始端的至少部分，绝缘件包括沿第二极片的卷绕方向依次设置的第一段、第二段和第三段，第一段设置于第一平直段与第一隔膜之间，第二段设置于第一拐角段与第一卷绕起始端之间，第三段设置于第二平直段与第二隔膜之间。由此，绝缘件可以从多个角度、多个方位来包覆第一卷绕起始端，不仅在电极组件的厚度方向上设置在第二极片最内圈与第一卷绕起始端之间，而且在电极组件的长度方向上设置在第二极片最内圈与第一卷绕起始端之间。从而最大程度地将第二极片最内圈与第一卷绕起始端隔绝开，缓解由于第二极片最内圈与第一卷绕起始端接触而发生的短路现象。
根据本申请的一些实施例，绝缘件包括第一绝缘件，第一绝缘件连接于第一隔膜和第二隔膜。
根据本申请的一些实施例，第一绝缘件包括第一基材层和第一胶质层，第一基材层通过第一胶质层连接于第一隔膜和第二隔膜。第一基材层可以保证绝缘件的绝缘性以及具有一定的强度，第二胶质层可以保证绝缘件粘接在第一隔膜和第二隔膜上。当然，第一胶质层和第二胶质层也可以具有绝缘性能，本申请实施例并不对此进行限定。
根据本申请的一些实施例，所述第一基材层的厚度为5mm-50mm。既保证了第一基材层可以预防正负极片短路，同时也可以缓解由于在第一拐角段和第一卷绕起始端之间设置较厚第一基材层而出现的第一拐角段断裂的问题。
根据本申请的一些实施例，所述第一胶质层与所述第一隔膜或所述第二隔膜在卷绕方向上的重叠长度为0.5mm-15mm。既保证了第一胶质层与第一隔膜之间具有足够的粘接力，同时也不会由于第一胶质层与第一隔膜在卷绕方向上的重叠长度过大导致的材料浪费的问题。
根据本申请的一些实施例，所述第一胶质层粘接强度不小于0.05N/mm。第一胶质层需要足够的粘接强度来保证电极组件浸入电解液后，第一胶质层仍然可以粘接固定在第一隔膜和第二隔膜上。
根据本申请的一些实施例，所述第一胶质层的厚度为2μm-20μm。既保证了第一胶质层可以和第一隔膜与第二隔膜牢固地粘接在一起。同时也可以缓解由于较厚的第一胶质层导致的材料浪费的问题。
根据本申请的一些实施例，所述第一基材层构造为PP材料层、PI材料层或PET材料层。PET材料层的柔韧性不及PP材料层或者PI材料层的柔韧性，PP材料层和PI材料层柔韧性较好，基材弯折后反弹力低。
根据本申请的一些实施例，所述绝缘件还包括：第二绝缘件，所述第二绝缘件连接于所述第二极片的最内圈的内表面。第二绝缘件一方面可以降低由于第一卷绕起始端与第二极片的最内圈接触出现正负极短路的几率，另一方面第一绝缘件也可以有效阻止了第二极片朝向第一卷绕起始端的侧面的正离子脱离，降低在第一卷绕起始端上出现析出金属的问题。
根据本申请的一些实施例，所述第二绝缘件包括：第二胶质层，所述第二胶质层连接于所述第二极片的最内圈的内表面。第二胶质层可以构造为绝缘部件从而可以降低由于第一卷绕起始端与第二极片的最内圈接触出现正负极短路的几率，同时第二胶质层也可以有效阻止了第二极片朝向第一卷绕起始端的侧面的正离子脱离，降低在第一卷绕起始端上出现析出金属的问题。
根据本申请的一些实施例，所述第二胶质层的厚度为2μm-20μm。既保证了第二胶质层可以阻止第一拐角段中的正离子脱离，同时也可以缓解由于在第一拐角段的内侧面设置第二胶质层而出现的第一拐角段断裂的问题。
根据本申请的一些实施例，所述第二胶质层在电解液中的粘接强度为0.02N/mm-0.4N/mm。第二胶质层需要足够的粘接强度来保证电极组件浸入电解液后，第二胶质层仍然可以粘接固定在第二极片最内圈的内表面。
根据本申请的一些实施例，在所述电极组件浸入电解液后，所述第二胶质层与所述第一基材层分离或所述第二胶质层溶解于所述电解液。由此，第二极片的最内圈的内表面仅仅粘接有第二胶质层或者完全不粘接任何部件，从而缓解了第二极片的最内圈由于受到过大的弹性力而出现的断裂问题。
根据本申请的一些实施例，在所述电极组件浸入电解液后，所述第二胶质层与所述第一基材层分离，所述第一基材层包括与所述第二胶质层连接的第一侧面和与所述第一胶质层连接的第二侧面，所述第一侧面的粗糙度小于所述第二侧面的粗糙度。由于第一侧面的粗糙度小于第二侧面的粗糙度，因此第二胶质层与第一侧面之间的粘接力要小于第二侧面与第一胶质层之间的粘接力，从而在电极组件浸入电解液后，第二胶质层更容易从第一基材层脱离。
根据本申请的一些实施例，所述第二绝缘件还包括：第二基材层，所述第二基材层通过所述第二胶质层连接于所述第二极片的最内圈的内表面。从而一方面，第一拐角段的内表面上由于贴附有第二胶质层和第二基材层，有效阻止了正离子脱离，另一方面也由于第一卷绕起始端上包覆有第一隔膜、第二隔膜和叠置的第一胶质层和第一基材层，从而可以有效缓解由于第一卷绕起始端凸出于第二卷绕起始端而出现的正负极片短路的技术问题。
根据本申请的一些实施例，所述第二基材层的延展率大于所述第二极片的延展率。从而，降低第二基材层的弯折部分施加在第二极片的最内圈的力，从而缓解第二极片的最内圈出现的断裂几率。
根据本申请的一些实施例，所述第二基材层的延展率为A，所述第一基材层的延展率为B，其中A大于B。由此，第二基材层的延展率大于第一基材层的延展率，从而第二基材层不会施加过多的弹性力给第一拐角段，从而缓解了第一拐角段容易出 现断裂的问题，且第一基材层可以更好地将第一隔膜和第二隔膜压合，减少由于振动或跌落试验造成的第一基材层从第一隔膜和第二隔膜脱离的技术问题。
根据本申请的一些实施例，所述第一绝缘件和所述第二绝缘件之间还设置有第三胶质层，在所述电极组件浸入电解液后，所述第三胶质层溶解于所述电解液，以使所述第一绝缘件和所述第二绝缘件分离。由于，第二极片的最内圈的内侧面以及第一卷绕起始端上均设置有绝缘部件，从而进一步降低了由于第一卷绕起始端凸出于第二卷绕起始端导致的正负极片短路的几率。
根据本申请的一些实施例，所述第三胶质层为亚克力胶层或橡胶层。
根据本申请的一些实施例，第二极片朝向第一卷绕起始端的一侧设置有无活性物质的避空区，避空区适于至少部分容纳绝缘件。通过将第二极片朝向第一卷绕起始端的一侧设置无活性物质的避空区，从而使得绝缘件的至少部分可以容纳在避空区中，降低了第二极片朝向第一卷绕起始端的部分的厚度，从而提升了电芯能量密度。
根据本申请的一些实施例，第一极片为负极片，第二极片为正极片。
第二方面，本申请实施例提供一种电芯，包括上述实施例的电极组件。
第三方面，本申请实施例提供一种用电设备，其特征在于，包括上述实施例的电芯。
本申请的附加方面和优点将在下面的描述中部分给出，部分将从下面的描述中变得明显，或通过本申请的实践了解到。
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为本申请一个实施例提供的电极组件的示意图；
图2为图1圈示A的局部放大示意图；
图3为本申请一个实施例提供的绝缘件的示意图；
图4为本申请一个实施例提供的绝缘件浸入电解液后的示意图；
图5为本申请另一个实施例提供的绝缘件的示意图；
图6为本申请另一个实施例提供的绝缘件浸入电解液的示意图；
图7为本申请另一个实施例提供的绝缘件浸入电解液的示意图；
图8为本申请另一个实施例提供的电极组件的示意图。
图标：电极组件100，
第一极片110，第一卷绕起始端111，
第二极片120，第一拐角段121，第一平直段122，第二平直段123，
隔膜130，第二卷绕起始端131，第一隔膜132，第二隔膜133，
绝缘件140，第一段a，第二段b，第三段c，第一绝缘件e，第二绝缘件d，
第一基材层141b，第二基材层141a，第三胶质层141c，第二胶质层142，第
一胶质层143，
第一侧面101，第二侧面102，避空区103，电极组件的厚度方向X，电极组件
的长度方向Y。
具体实施方式
为使本申请实施例的目的、技术方案和优点更加清楚，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
除非另有定义，本申请所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本申请中在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，不是旨在于限定本申请；本申请的说明书和权利要求书及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。本申请的说明书和权利要求书或上述附图中的术语“第一”、“第二”等是用于区别不同对象，而不是用于描述特定顺序或主次关系。
在本申请中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是，本申请所描述的实施例可以与其它实施例相结合。
在本申请的描述中，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”、“附接”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，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
本申请中术语“和/或”，仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本申请中字符“/”，一般表示前后关联对象是一种“或”的关系。
本申请中出现的“多个”指的是两个以上(包括两个)，同理，“多组”指的是两组以上(包括两组)，“多片”指的是两片以上(包括两片)。
现有MMT(Mid-Mid-Tab，正极耳设置在正极片的中间，负极耳设置在负极耳的中间)结构普遍采用卷针夹紧隔膜进行卷绕，导致最内圈存在四层隔膜，且电芯的厚度增加，进而出现电芯在厚度方向上能量密度损失的问题。
现有技术中，一般可以采用极片和隔膜平切的工艺，来解决由于电极组件的内圈出现四层隔膜的技术问题。极片包括：极片起始段，极片起始段在极片的卷绕方向 上位于极片的内侧部分；隔膜包括：隔膜起始段，隔膜起始段在隔膜的卷绕方向上位于隔膜的内侧部分。极片和隔膜平切的工艺可以为：极片起始段的起始端与隔膜起始段的起始端平齐，从而电极组件的内圈不会出现没有包覆极片的多层隔膜，改善由于内圈的多层隔膜导致电极组件在厚度方向上的能量密度损失的问题。
但是，极片和隔膜平切的工艺中，由于极片起始段的起始端与隔膜起始段的起始端平齐，隔膜起始段的起始端没有超出极片起始段的起始端，或者隔膜起始段的起始端和极片起始段的起始端之间的距离较小，从而在电芯滚筒或者跌落测试后，隔膜会出现收缩而导致极片起始段的起始端从隔膜起始段内伸出，从而极片起始段的起始端会裸露出来，进而容易出现极性相反的两个极片接触而短路的问题。
为此本申请实施例提出了一种电极组件100，该电极组件100不仅可以解决电极组件的最内圈存在多层隔膜导致电芯厚度增加的问题，同时还可以缓解由于隔膜收缩导致的极片裸露、进而导致极性相反的两个极片接触而短路的问题。
在本申请的一些实施例中，电极组件100构造为卷绕式结构，卷绕式结构是通过固定卷针的卷绕，将分条后的第一极片110、隔膜130、第二极片120按照顺序卷绕挤压成圆柱形或椭圆柱形或方形，再放入适合的外壳中，极片的大小、卷绕的圈数等参数根据电池设计容量来进行确定。
电极组件100包括：第一极片110、第二极片120和隔膜130，隔膜130设置在第一极片110和第二极片120之间，第一极片110和第二极片120为极性相反的极片，第一极片110和第二极片120中的一个为正极片，第一极片110和第二极片120中的另一个为负极片。在电芯充放电过程中，活性离子(例如锂离子)在第一极片110和第二极片120之间往返嵌入和脱出。隔膜130设置在第一极片110和第二极片120之间，可以起到防止第一极片110和第二极片120短路的作用，同时可以使活性离子通过。
正极片可以包括正极集流体以及设置在正极集流体至少一个表面的正极活性材料。同理，负极片可以包括负极集流体以及设置在负极集流体至少一个表面的负极活性物质。本申请对隔膜130的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔膜130。
作为示例，正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用表面镀银处理的铝、表面镀银处理的不锈钢、不锈钢、铜、铝、镍、炭精电极、碳、镍或钛等。复合集流体可包括高分子材料基层和金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯、聚对苯二甲酸乙二醇酯、聚对苯二甲酸丁二醇酯、聚苯乙烯、聚乙烯等的基材)上而形成。
作为示例，正极活性材料可包括以下材料中的至少一种：含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。
负极活性物质可采用本领域公知的用于电池的负极活性物质。作为示例，负极活性物质可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮 复合物以及硅合金中的至少一种。锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性物质的传统材料。这些负极活性物质可以仅单独使用一种，也可以将两种以上组合使用。
作为示例，隔膜130的主要材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯，陶瓷中的至少一种。隔膜130可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔膜130为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。隔膜130可以是单独的一个部件位于正负极之间，也可以附着在正负极的表面。
在一些实施方式中，隔膜130为固态电解质。固态电解质设于正极和负极之间，同时起到传输离子和隔离正负极的作用。
如图1和图8所示，第一极片110包括第一卷绕起始端111，隔膜130包括第二卷绕起始端131，沿电极组件100的卷绕方向，第一卷绕起始端111与第二卷绕起始端131之间的距离不超过5mm。第一卷绕起始端111为第一极片110最先入卷的端部，第二卷绕起始端131为隔膜130最先入卷的端部，本申请实施例中第一极片110和隔膜130采用平切的工艺，因此第一卷绕起始端111和第二卷绕起始端131平齐。本申请实施例中的平齐为第一卷绕起始端111和第二卷绕起始端131之间的距离不超过5mm。第一卷绕起始端111可以超出第二卷绕起始端131的距离不大于5mm，或者第一卷绕起始端111可以与第二卷绕起始端131完全平齐，或者第二卷绕起始端131可以超出第一卷绕起始端111的距离不超过5mm。
在本申请的一些实施例中，电极组件100还包括绝缘件140，绝缘件140设置在第二极片120的最内圈和第一卷绕起始端111之间，以将第一卷绕起始端111和第二极片120隔开。
绝缘件140可以是不导电的材质构成，例如绝缘件140可以为塑料件、橡胶件等。绝缘件140设置在第二极片120的最内圈和第一卷绕起始端111之间指的是：绝缘件140可以设置在第二极片120的最内圈朝向第一卷绕起始端111的侧面上，绝缘件140也可以设置在第一卷绕起始端111上，或者绝缘件140设置在将第二极片120的最内圈和第一卷绕起始端111间隔开的间隙内。当然，可以理解的是，若绝缘件140设置在第一卷绕起始端111上的隔膜130上，则也可以认为绝缘件140设置在第一卷绕起始端111上。
由此，即使电芯摔落或者进行跌落测试后，隔膜130发生收缩，原来彼此平齐的第一卷绕起始端111和第二卷绕起始端131不在平齐或者二者之间的距离变大，从而第一卷绕起始端111从两层隔膜130之间裸露出来，其也会由于设置在第一卷绕起始端111和第二极片120的最内圈之间的绝缘件140，不会出现第一卷绕起始端111与第二极片120接触而发生短路现象。
在本申请的一些实施例中，如图1和图2所示，第二极片120的最内圈包括第一拐角段121，第一拐角段121与第一卷绕起始端111相对设置，绝缘件140的至少一部分设置于第一拐角段121与第一卷绕起始端111之间。
第一拐角段121可以为第二极片120的最内圈的在卷绕方向上的第一个拐角段，第一拐角段121可以仅仅包括弧形段，当然第一拐角段121也可以包括弧形段以及连接在弧形段两端的平直段，本申请实施例不对第一拐角段121的具体结构进行限定，只要保证第一拐角段121设置在第一卷绕起始端111附近即可。
在本申请的一些实施例中，第一拐角段121与第一卷绕起始端111相对设置，第一拐角段121可以设置在第一卷绕起始端111的附近，第一拐角段121可以与第一卷绕起始端111在电极组件100的长度方向Y上正对。第一拐角段121的一部分可以与第一卷绕起始端111在电极组件100的长度方向Y上正对，第一拐角段121的另一部分也可以与第一卷绕起始端111在电极组件100的厚度方向X上正对。
其中，绝缘件140的至少一部分设置在第一拐角段121与第一卷绕起始端111之间。也就是说，绝缘件140的至少一部分可以设置在第一拐角段121上朝向第一卷绕起始端111的区域上，绝缘件140的至少一部分也可以设置在第一卷绕起始端111朝向第一拐角段121的区域上，当然绝缘件140的至少一部分还可以设置在第一拐角段121和第一卷绕起始端111之间的空隙里，只要保证绝缘件140的至少一部分设置在第一拐角段121和第一卷绕起始端111之间即可。
在本申请的一些实施例中，绝缘件140的一部分可以设置在电极组件100的长度方向Y上位于第一拐角段121与第一卷绕起始端111之间，绝缘件140的一部分也可以在电极组件100的长度方向Y上位于第一拐角段121与所述第一卷绕起始端111之间。
例如，绝缘件140的一部分可以在电极组件100的长度方向Y上设置在第一拐角段121朝向第一卷绕起始端111的区域上，绝缘件140的一部分也可以在电极组件100的长度方向Y上设置在第一卷绕起始端111朝向第一拐角段121的区域上。
由于绝缘件140的至少一部分设置于第一拐角段121与第一卷绕起始端111之间，因此即使在隔膜130发生收缩、第一卷绕起始端111凸出于第二卷绕起始端131，第一卷绕起始端111也会被绝缘件140阻隔，而不会出现第一卷绕起始端111与第一拐角段121接触而导致正负极片短路的技术问题。在该实施例中，绝缘件140可以不阻止隔膜130收缩，而是通过设置在第一卷绕起始端111与第一拐角段121之间来阻止第一卷绕起始端111和第一拐角段121之间接触。
在本申请的一些实施例中，如图1和图2所示，隔膜130包括位于第一极片110两侧的第一隔膜132和第二隔膜133。需要说明的是，第一极片110的两侧指的是第一极片110在厚度方向上的两侧。
绝缘件140绕过第一卷绕起始端111，且绝缘件140的两端分别与第一隔膜132和第二隔膜133连接。第一卷绕起始端111具有一个端面，绝缘件140绕过第一卷绕起始端111的端面且弯折后分别与第一隔膜132和第二隔膜133连接。也就是说，绝缘件140可以构造为“C”形结构，绝缘件140在与第一隔膜132和第二隔膜133连接在一起后，绝缘件140可以将第一卷绕起始端111的端面包裹住。
由于绝缘件140绕过第一卷绕起始端111且分别与第一隔膜132和第二隔膜133连接，从而可以限制隔膜130发生收缩，有效缓解了第一卷绕起始端111从第二卷 绕起始端131伸出的问题。
在本申请的一些实施例中，如图2所示，第二极片120的最内圈还包括第一平直段122和第二平直段123，第一拐角段121连接在第一平直段122和第二平直段123之间，第一平直段122、第一拐角段121和第二平直段123环绕第一卷绕起始端111的至少部分。第一平直段122、第一拐角段121和第二平直段123可以沿第二极片120的卷绕方向上依次设置。
第一拐角段121可以构造为弧形段，第一平直段122和第二平直段123可以设置在弧形段的两端且可以不发生弯折、构造为平直的两段，第一平直段122、第一拐角段121和第二平直段123可以构造为“C”形结构。“C”形结构的第一平直段122、第一拐角段121和第二平直段123环绕第一卷绕起始端111的至少部分。
绝缘件140包括沿第一极片110的卷绕方向依次设置的第一段a、第二段b和第三段c，第一段a设置于第一平直段122与第一隔膜132之间，第二段b设置在第一拐角段121与第一卷绕起始端111之间，第三段c设置于第二平直段123与第二隔膜133段之间。
第一段a、第二段b和第三段c可以构造为“C”形结构，也就是说，绝缘件140的形状可以与第一拐角段121的形状大致相同，从而绝缘件140可以更好地包覆第一卷绕起始端111，从而有效缓解第一卷绕起始端111与第二极片120最内圈接触而出现的短路问题。
第一段a设置在第一平直段122与第一隔膜132之间，也即第一段a、第一平直段122和第一隔膜132在电极组件100的厚度方向X上相对；第二段b设置在第一拐角段121与第一卷绕起始端111之间，也即第二段b、第一拐角段121和第一卷绕起始端111的端面在电极组件100的长度方向Y上正对，第三段c设置在第二平直段123与第二隔膜133之间，也即第三段c、第二平直段123和第二隔膜133在电极组件100的厚度方向X上正对。
由此，绝缘件140可以从多个角度、多个方位来包覆第一卷绕起始端111，不仅在电极组件100的厚度方向X上设置在第二极片120最内圈与第一卷绕起始端111之间，而且在电极组件100的长度方向Y上设置在第二极片120最内圈与第一卷绕起始端111之间。从而最大程度地将第二极片120最内圈与第一卷绕起始端111隔绝开，缓解由于第二极片120最内圈与第一卷绕起始端111接触而发生的短路现象。
在本申请的一些实施例中，如图3-图6所示，绝缘件140包括第一绝缘件e，第一绝缘件e连接于第一隔膜132和第二隔膜133。第一绝缘件e可以将第一卷绕起始端111包覆住，从而可以降低由于第一卷绕起始端111凸出于第二卷绕起始端131而出现的正负极片接触、短路的几率。
第一绝缘件e可以包括第一基材层141b和第一胶质层143，第一基材层141b通过第一胶质层143连接于第一隔膜132和第二隔膜133。在电极组件100未浸入电解液中时，第一基材层141b可以通过第二胶质层142连接于第二极片120的最内圈的内表面。
第一基材层141b可以保证绝缘件140的绝缘性以及具有一定的强度，第一胶 质层143可以保证第一基材层141b粘接在第一隔膜132和第二隔膜133上。当然，第一胶质层143也可以具有绝缘性能，本申请实施例并不对此进行限定。
在本申请的一些实施例中，如图3和图5所示，第一基材层141b的厚度t2可以为5mm-50mm。第一基材层141b的厚度t2直接决定第二极片120在卷绕过程中是否顺畅，第一基材层141b的厚度t2越大，则第二极片120在卷绕过程中第一拐角段121的弯折难度越大，第一基材层141b的厚度t2越小，则第二极片120在卷绕过程中第一拐角段121的弯折难度越小；而且较厚的第一基材层141b在弯折之后还会施加给第一拐角段121较大的弹性力，从而容易出现第一拐角段121断裂的问题。
本申请实施例中，将第一基材层141b的厚度t2限制在5μm-50μm。既保证了第一基材层141b可以预防正负极片短路，同时也可以缓解由于在第一拐角段121和第一卷绕起始端111之间设置较厚第一基材层141b而出现的、电极组件100卷绕过程中第一拐角段121断裂的问题。
例如，第一基材层141b的厚度t2可以为5μm、10μm、15μm、20μm、25μm、30μm、35μm、40μm、45μm或50μm，本申请实施例不对第一基材层141b的厚度t2进行具体限定，只要保证第一基材层141b的厚度落入上述范围即可。
在本申请的一些实施例中，如图1所示，第一胶质层143与第一隔膜132或第二隔膜133在卷绕方向上的重叠长度L1为0.5mm-15mm。
第一胶质层143与第一隔膜132可以粘接固定，第一胶质层143与第一隔膜132之间的粘接区域的面积直接影响第一胶质层143和第一隔膜132之间的粘接力，而第一胶质层143与第一隔膜132在卷绕方向上的重叠长度直接决定了第一胶质层143与第一隔膜132之间的粘接区域的面积。第一胶质层143与第一隔膜132在卷绕方向上的重叠长度越长，则第一胶质层143与第一隔膜132之间的粘接力越大；第一胶质层143与第一隔膜132在卷绕方向上的重叠长度越短，则第一胶质层143与第一隔膜132之间的粘接力越小。
本申请实施例将第一胶质层143与第一隔膜132或第二隔膜133在卷绕方向上的重叠长度设置为0.5mm-15mm，既保证了第一胶质层143与第一隔膜132之间具有足够的粘接力，同时也不会由于第一胶质层143与第一隔膜132在卷绕方向上的重叠长度过大导致的材料浪费的问题。
第一胶质层143与第二隔膜133可以粘接固定，第一胶质层143与第二隔膜133之间的粘接区域的面积直接影响第一胶质层143和第二隔膜133之间的粘接力，而第一胶质层143与第二隔膜133在卷绕方向上的重叠长度直接决定了第一胶质层143与第二隔膜133之间的粘接区域的面积。第一胶质层143与第二隔膜133在卷绕方向上的重叠长度越长，则第一胶质层143与第二隔膜133之间的粘接力越大；第一胶质层143与第二隔膜133在卷绕方向上的重叠长度越短，则第一胶质层143与第二隔膜133之间的粘接力越小。
本申请实施例将第一胶质层143与第一隔膜132或第二隔膜133在卷绕方向上的重叠长度设置为0.5mm-15mm，既保证了第一胶质层143与第二隔膜133之间具有足够的粘接力，同时也不会由于第一胶质层143与第二隔膜133在卷绕方向上的重叠 长度过大导致的材料浪费的问题。
在本申请的一些实施例中，第一胶质层143的粘接强度不小于0.05N/mm。第一胶质层143需要足够的粘接强度来保证电极组件100浸入电解液后，第一胶质层143仍然可以粘接固定在第一隔膜132和第二隔膜133上。
第一胶质层143的粘接强度可以为0.05N/mm、0.1N/mm、0.15N/mm、0.2N/mm、0.25N/mm、0.3N/mm等。本申请实施例不对第一胶质层143在电解液中的粘接强度进行限定，只要保证第一胶质层143在电解液中的粘接强度在上述范围内即可。
在本申请的一些实施例中，如图3和图5所示，第一胶质层143的厚度t3为2μm-20μm。第一胶质层143的厚度t3直接决定第一胶质层143与第一隔膜132和第二隔膜133之间的粘接力，第一胶质层143的厚度t3越大，则第一胶质层143与第一隔膜132和第二隔膜133之间的粘接力越大，第一胶质层143的厚度t3越小，则第一胶质层143与第一隔膜132和第二隔膜133之间的粘接力越小。
本申请实施例中，将第一胶质层143的厚度t3限制在2μm-20μm。既保证了第一胶质层143可以和第一隔膜132与第二隔膜133牢固地粘接在一起。同时也可以缓解由于较厚的第一胶质层143导致的材料浪费的问题。
例如，第一胶质层143的厚度t3可以为2μm、5μm、8μm、11μm、14μm、17μm或20μm，本申请实施例不对第一胶质层143的厚度t3进行具体限定，只要保证第一胶质层143的厚度落入上述范围即可。
在本申请的一些实施例中，如图7所示，绝缘件仅包括第一绝缘件e，第一绝缘件e连接于第一隔膜132和第二隔膜133上。也就是说，在第二极片120的最内圈和第一卷绕起始端111之间仅仅设置有一个第一绝缘件e，且该第一绝缘件e仅连接于第一隔膜132和第二隔膜133，第二极片120的最内圈的内侧面上没有贴附有绝缘部件，从而第二极片120的最内圈的内侧面不再受到由于绝缘部件弯折而产生的弹性力，大大降低了第二极片120的最内圈断裂的几率。
在电芯注液前，第一绝缘件e可以通过胶质层连接于第二极片120的最内圈的内侧面，在注液完成后，电极组件100浸入到电解液中，此时第二极片120的最内圈的内侧面上的胶质层溶解于电解液中，第一绝缘件e与第二极片120的最内圈分离开，第一绝缘件e连接于第一隔膜132和第二隔膜133上，从而缓解了由于隔膜130收缩导致第一卷绕起始端111凸出于第二卷绕起始端131而出现的正负极片短路的现象。
在本申请的一些实施例中，在电芯注液前，第一绝缘件e可以通过胶质层连接于第二极片120的最内圈的内侧面，在注液完成后，电极组件100浸入到电解液中，此时第二极片120的最内圈的内侧面上的胶质层不仅与第一绝缘件e脱离，也与第二极片120的最内圈脱离，从而第一绝缘件e与第二极片120的最内圈分离开。
在本申请的一些实施例中，如图7所示，第一绝缘件e可以包括第一基材层141b和第一胶质层143，具体连接方式和效果如之前描述，这里不再赘述。当然第一绝缘件e也可以仅构造为胶质层，第一绝缘件e不仅具有绝缘性能还具有粘接性能，第一绝缘件e可以粘接在第一隔膜132和第二隔膜133上。从而不仅可以降低由于第一 卷绕起始端111与第二极片120的最内圈接触出现正负极短路的几率，同时也在一定程度上降低了电极组件100在厚度方向上的能量密度损失。
在本申请的一些实施例中，绝缘件还包括第二绝缘件d，第二绝缘件d连接于第二极片120的最内圈的内表面。第二绝缘件d一方面可以降低由于第一卷绕起始端111与第二极片120的最内圈接触出现正负极短路的几率，另一方面第一绝缘件d也可以有效阻止了第二极片120朝向第一卷绕起始端111的侧面的正离子脱离，降低在第一卷绕起始端111上出现析出金属的问题。
在本申请的一些实施例中，第二绝缘件d包括第二胶质层142，第二胶质层142连接于第二极片120的最内圈的内表面。第二胶质层142可以粘接固定在第二极片120的最内圈的内表面，第二胶质层142可以构造为绝缘部件从而可以降低由于第一卷绕起始端111与第二极片120的最内圈接触出现正负极短路的几率，同时第二胶质层142也可以有效阻止了第二极片120朝向第一卷绕起始端111的侧面的正离子脱离，降低在第一卷绕起始端111上出现析出金属的问题。
在本申请的一些实施例中，在电极组件100未浸入电解液时，第一基材层141b可以通过第二胶质层142连接于第二极片120的最内圈的内表面，在电极组件100浸入电解液后，第一基材层141b可以脱离开第二极片120。
由此，在电极组件100浸入电解液后，第二极片120的最内圈的内表面不会一直附着有全部的第一基材层141b，从而降低由于第一基材层141b弯折后的弹性力施加给第二极片120的第一拐角段121而导致第一拐角段121容易出现断裂问题的几率。
在电极组件100卷绕前，第一基材层141b首先通过第二胶质层142粘接在第二极片120上，此时第一基材层141b上的第一胶质层143不与第一隔膜132和第二隔膜133粘接；然后在卷绕的过程中，第二极片120上的最内圈的一部分发生弯折，因此第二极片120最内圈的一部分形成第一拐角段121，同时贴附在第一拐角段121的内侧面上的第一基材层141b、第二胶质层142和第一胶质层143也发生弯折，然后第一胶质层143粘接在第一隔膜132和第二隔膜133上。
在电极组件100浸入电解液后，若第一基材层141b仍然通过第二胶质层142粘接在第二极片120的最内圈的内表面，第一基材层141b因为弯折而产生的弹性应力会施加在第一拐角段121的内侧面，因此可能会由此出现第一拐角段121断裂的问题。
在本申请的一些实施例中，电极组件100浸入电解液后，第二胶质层142与第一绝缘件e(例如，第一基材层141b)分离。也就是说，第二胶质层142与第一基材层141b之间的粘接力相较于第一胶质层143与第一基材层141b之间的粘接力较低，因此在电极组件100浸入电解液后，第二胶质层142更容易与第一基材层141b脱离，而第一基材层141b与第一胶质层143粘接在一起，第一基材层141b通过第一胶质层143粘接在第一隔膜132和第二隔膜133上。
根据本申请的一些实施例，可以通过电晕处理第一基材层141b上与第二胶质层142粘接的表面以及第一基材层141b上与第一胶质层143粘接的表面。从而达到 在第一基材层141b经过电晕处理后，第一胶质层143相较于第二胶质层142与第一基材层141b粘接的更加牢固。
第一基材层141b包括与第二胶质层142连接的第一侧面101以及与第一胶质层143连接的第二侧面102，第一侧面101的粗糙度小于第二侧面102的粗糙度。需要说明的是，表面的粗糙度与胶质层粘接在表面上的粘接力成正比，即表面的粗糙度越大，则胶质层粘接在表面上后，胶质层与表面的粘接力越大；表面的粗糙度越小，则胶质层粘接在表面上后，胶质层与表面的粘接力越小。
由于第一侧面101的粗糙度小于第二侧面102的粗糙度，因此第二胶质层142与第一侧面101之间的粘接力要小于第二侧面102与第一胶质层143之间的粘接力，从而在电极组件100浸入电解液后，第二胶质层142更容易从第一基材层141b脱离。
第一侧面101的粗糙度和第二侧面102的粗糙度可以通过电晕处理来实现，当然也可以通过其他方式来实现，本申请实施例不对第一侧面101的粗糙度和第二侧面102的粗糙度的形成方式进行限定。
在本申请的一些实施例中，在电极组件100浸入电解液后，第二胶质层142溶解于电解液。由此，第二极片120的最内圈的内表面完全不粘接任何部件，从而缓解了由于第二胶质层142弯折产生的弹性力且施加在第二极片120的最内圈而出现的断裂问题。由于第一卷绕起始端111被第一隔膜132、第二隔膜133以及叠置的第一基材层141b和第一胶质层143包覆，第一卷绕起始端111上没有裸露的集流体暴露出来，因此即使第二极片120的最内圈的内表面没有粘接有第二胶质层142，第一卷绕起始端111上仍然不会出现析出正离子的问题。
在本申请的一些实施例中，如图3和图5所示，第二胶质层142的厚度t1为2μm-20μm。第二胶质层142的厚度直接决定第二极片120在卷绕过程中是否顺畅，第二胶质层142的厚度越大，则第二极片120在卷绕过程中第一拐角段121的弯折难度越大，第二胶质层142的厚度越小，则第二极片120在卷绕过程中第一拐角段121的弯折难度越小；而且较厚的第二胶质层142在弯折之后还会施加给第一拐角段121较大的弹性力，从而容易出现第一拐角段121断裂的问题。
本申请实施例中，将第二胶质层142的厚度t1限制在2μm-20μm。既保证了第二胶质层142可以阻止第一拐角段121中的正离子脱离，同时也可以缓解由于在第一拐角段121的内侧面设置第二胶质层142而出现的第一拐角段121断裂的问题。
例如，第二胶质层142的厚度t1可以为2μm、5μm、8μm、11μm、14μm、17μm或20μm，本申请实施例不对第二胶质层142的厚度t1进行具体限定，只要保证第二胶质层142的厚度落入上述范围即可。
在本申请的一些实施例中，第二胶质层142在电解液中的粘接强度为0.02N/mm-0.4N/mm。第二胶质层142需要足够的粘接强度来保证电极组件100浸入电解液后，第二胶质层142仍然可以粘接固定在第二极片120最内圈的内表面。
第二胶质层142在电解液中的粘接强度可以为0.02N/mm、0.05N/mm、0.1N/mm、0.15N/mm、0.2N/mm、0.25N/mm、0.3N/mm、0.35N/mm或0.4N/mm。本申请实施例不对第二胶质层142在电解液中的粘接强度进行限定，只要保证第二胶质 层142在电解液中的粘接强度在上述范围内即可。
在本申请的另一些实施例中，如图5和图6所示，第二绝缘件d还包括第二基材层141a，第二基材层141a和第一基材层141b可以起到绝缘的作用。第二胶质层142设置于第二基材层141a与第二极片120的最内圈的内侧面之间。
第二极片120最内圈的内表面上粘接有第二胶质层142和第二基材层141a，第一隔膜132和第二隔膜133上粘接有第一胶质层143和第一基材层141b。从而一方面，第一拐角段121的内表面上由于贴附有第二胶质层142和第二基材层141a，有效阻止了正离子脱离，另一方面也由于第一卷绕起始端111上包覆有第一隔膜132、第二隔膜133和叠置的第一胶质层143和第一基材层141b，从而可以有效缓解由于第一卷绕起始端111凸出于第二卷绕起始端131而出现的正负极片短路的技术问题。
在本申请的一些实施例中，第二基材层114a的延展率大于第二极片120的延展率，由此在第二基材层114a通过第二胶质层142粘接在第二极片120的第一拐角段121的内侧面上，弯折的第二基材层114a由于延展率较大，不会施加过多的弹性力给第一拐角段121，从而缓解了第一拐角段121容易出现断裂的问题。
第二基材层114a的延展率为A，第一基材层114b的延展率为B，第二基材层114a的延展率A大于第一基材层114b的延展率B。从而，降低第二基材层114a的弯折部分施加在第二极片120的最内圈的力，从而缓解第二极片120的最内圈出现的断裂几率。由于第一基材层114b通过第一胶质层143粘接固定在第一隔膜132和第二隔膜133上，从而第一基材层114b的延展率可以不做过多要求。当然，第一基材层114b的延展率不能过大，最好小于第二基材层114a的延展率，从而第一基材层114b可以更好地将第一隔膜132和第二隔膜133压合，减少由于振动或跌落试验造成的第一基材层114b从第一隔膜132和第二隔膜133脱离的技术问题。
在本申请的一些实施例中，第二基材层114a的延展率为A，第一基材层114b的延展率为B，其中A大于B。由此，第二基材层114a的延展率大于第一基材层114b的延展率，从而第二基材层114a不会施加过多的弹性力给第一拐角段121，从而缓解了第一拐角段121容易出现断裂的问题，且第一基材层114b可以更好地将第一隔膜132和第二隔膜133压合，减少由于振动或跌落试验造成的第一基材层114b从第一隔膜132和第二隔膜133脱离的技术问题。
在本申请的一些实施例中，第一绝缘件e和第二绝缘件d之间还设置有第三胶质层141c，在电极组件100浸入电解液后，第三胶质层141c溶解于电解液，以使第一绝缘件e和第二绝缘件d分离。由此，第二极片120的最内圈的内侧面以及第一卷绕起始端111上均设置有绝缘部件，从而进一步降低了由于第一卷绕起始端111凸出于第二卷绕起始端131导致的正负极片短路的几率。
根据本申请的一些实施例，第三胶质层141c为亚克力胶层或橡胶层。第三胶质层141c设置成亚克力胶层或橡胶层，可以在电极组件100浸入到电解液后，发生溶解，从而实现在电极组件100浸入电解液后，第三胶质层141c溶解于电解液，以使第二基材层141a和第一基材层141b分离。本申请不对第三胶质层141c的具体类型进行限定，只要保证第三胶质层141c在电极组件100浸入电解液后，第三胶质层141c溶 解于电解液中即可。
在本申请的一些实施例中，在电极组件100浸入电解液后，第三胶质层141c与第一绝缘件e分离且第三胶质层141c也与第二绝缘件d分离。
如上述实施例描述，第一绝缘件e包括第一基材层141b和第一胶质层143，第一基材层141b通过第一胶质层143粘接在第一隔膜142和第二隔膜143上；第二绝缘件d包括第二基材层141a和第二胶质层142，第二基材层141a通过第二胶质层142粘接在第二极片120的最内圈的内侧面。
在电极组件100未浸入电极液时，第一基材层141b背离第一胶质层143的侧面和第三胶质层141c粘接固定，第二基材层141a背离第二胶质层142的侧面和第三胶质层141c粘接固定。在电极组件100浸入电解液后，第三胶质层141c与第一基材层141b分离且第三胶质层141c也与第二基材层141a分离。
可以通过电晕处理第二基材层141a上与第三胶质层141c粘接的表面以及第一基材层141b上与第三胶质层141c粘接的表面。从而达到在第一基材层141b和第二基材层141a经过电晕处理后，且在电极组件100浸入到电解液后，第三胶质层141c可以容易地从第二基材层141a和第一基材层141b上脱离。
第二基材层141a上与第三胶质层141c粘接的表面的粗糙度可以设置的较小，从而方便在电极组件100浸入到电解液后，第三胶质层141c可以容易地从第二基材层141a脱离。第一基材层141b上与第三胶质层141c粘接的表面的粗糙度也可以设置的较小，从而方便在电极组件100浸入到电解液后，第三胶质层141c可以容易地从第一基材层141b脱离。
需要说明的是，表面的粗糙度与胶质层粘接在表面上的粘接力成正比，即表面的粗糙度越大，则胶质层粘接在表面上后，胶质层与表面的粘接力越大；表面的粗糙度越小，则胶质层粘接在表面上后，胶质层与表面的粘接力越小。
第二基材层141a上与第三胶质层141c粘接的表面的粗糙度可以与第一基材层141b上与第三胶质层141c粘接的表面的粗糙度相同。第二基材层141a上与第三胶质层141c粘接的表面的粗糙度和第一基材层141b上与第三胶质层141c粘接的表面的粗糙度可以通过电晕处理来实现，当然也可以通过其他方式来实现，本申请实施例不对第二基材层141a上与第三胶质层141c粘接的表面的粗糙度和第一基材层141b上与第三胶质层141c粘接的表面的粗糙度的形成方式进行限定。
在申请的一些实施例中，第一基材层141b构造为PP(Polypropylene，聚丙烯)材料层、PI(Polyimide，聚酰亚胺)材料层或PET(Polyethylene terephthalate，涤纶树脂)材料层。
在本申请的一些实施例中，第二基材层141a可以为PP材料层或者PI材料层，PP材料层和PI材料层柔韧性较好，基材弯折后反弹力低，从而将第二基材层141a通过第二胶质层142粘接在第二极片120最内圈的内表面时，第二基材层141a施加在第一拐角段121上的弹性力较小，从而有效的缓解了第一拐角段121容易断裂的问题。
第一基材层141b可以为PET材料层。PET材料层的柔韧性不及PP材料层 或者PI材料层的柔韧性，从而PET材料层可以更好地将第一隔膜132和第二隔膜133压合，减少由于振动或跌落试验造成的第一基材层141b从第一隔膜132和第二隔膜133脱离的技术问题。
在本申请的一些实施例中，如图8所示，第二极片120朝向第一卷绕起始端111的一侧设置有避空区103，避空区103上无活性物质，避空区103适于至少部分容纳绝缘件140。由于第二极片120的最内圈和第一卷绕起始端111之间设置有绝缘件140，绝缘件140的至少部分，例如绝缘件140的第二胶质层142粘接在第二极片120的最内圈，或者绝缘件140的第二胶质层142和第二基材层141a粘接在第二极片120的最内圈，因此第二极片120的最内圈朝向第一卷绕起始端111的区域由于被绝缘件140的至少部分阻挡而不参与充放电反应。因此，本申请实施例中，通过将第二极片120朝向第一卷绕起始端111的一侧设置无活性物质的避空区103，从而使得绝缘件140的至少部分可以容纳在避空区103中，降低了第二极片120朝向第一卷绕起始端111的部分的厚度，从而提升了电芯能量密度。
在本申请的一些实施例中，第一极片110为负极片，第二极片120为正极片。负极片的卷绕起始端与正极片的最内圈之间设置有绝缘件140，从而即使隔膜130发生收缩，负极片的卷绕起始端凸出于隔膜130的卷绕起始端，负极片的卷绕起始端也不会与正极片发生接触，有效缓解了正负极片发生短路的情况。
下面详细描述本申请电极组件100的一个实施例。
本实施例中的电极组件100未浸入到电解液中。电极组件100包括：极性相反的第一极片110和第二极片120，以及设置在第一极片110和第二极片120之间的隔膜130，第一极片110包括第一卷绕起始端111，隔膜130包括第二卷绕起始端131，第一卷绕起始端111和第二卷绕起始端131在极片的卷绕方向上大致平齐。电极组件100还包括绝缘件140，绝缘件140设置在第二极片120的最内圈和第一卷绕起始端111之间。
隔膜130包括位于第一极片110两侧的第一隔膜132和第二隔膜133，绝缘件140绕过第一卷绕起始端111，且绝缘件140分别与第一隔膜132和第二隔膜133连接。
第二极片120的最内圈包括第一拐角段121以及与第一拐角段121的两端分别相连的第一平直段122和第二平直段123，绝缘件140包括在卷绕方向上依次连接的第一段a、第二段b和第三段c，第一段a设置在第一平直段122与第一隔膜132之间，第二段b设置在第一拐角段121与第一卷绕起始端111之间，第三段c设置在第二平直段123与第二隔膜133之间。
绝缘件包括第一基材层141b、第二胶质层142和第一胶质层143，第二胶质层142粘接在第二极片120的最内圈，第一基材层141b通过第一胶质层143粘接在第一隔膜132和第二隔膜133上。绝缘件还可以包括：第二基材层141a，第二基材层141a通过第二胶质层142粘接在第二极片120的最内圈，第一基材层141b通过第一胶质层143粘接在第一隔膜132和第二隔膜133上。
第二极片120朝向第一卷绕起始端111的一侧设置有无活性物质的避空区 103，避空区103适于至少部分容纳绝缘件140，第一极片110为负极片，第二极片120为正极片。
在本申请的一个实施例中，电芯包括上述实施例的电极组件100，由于根据本申请实施例的电芯设置有上述的电极组件，因此该电芯的稳定性得到显著提升，同时有效降低了正负极片出现短路的问题的几率。
下面简单描述本申请实施例的用电设备。
根据本申请实施例的用电设备包括上述的电芯，由于根据本申请实施例的用电设备设置有上述电芯，因此该用电设备可以缓解由于隔膜130收缩导致的正负极片接触且短路的现象。
用电设备可以为但不限于手机、平板电脑、笔记本电脑、电动玩具、电动工具、电动自行车、电动摩托车、电动汽车、轮船、航天器等等。其中，电动玩具可以包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等，航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
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 (26)

  1. 一种电极组件，其特征在于，所述电极组件为卷绕式结构，所述电极组件包括第一极片、第二极片和隔膜，所述隔膜设置于所述第一极片和所述第二极片之间，所述第一极片包括第一卷绕起始端，所述隔膜包括第二卷绕起始端，沿所述电极组件的卷绕方向，所述第一卷绕起始端与所述第二卷绕起始端之间的距离不超过5mm；
    其中，所述电极组件还包括绝缘件，所述绝缘件设置于所述第二极片的最内圈和所述第一卷绕起始端之间，以将所述第一卷绕起始端和所述第二极片隔开。
  2. 根据权利要求1所述的电极组件，其特征在于，所述第二极片的最内圈包括第一拐角段，所述第一拐角段与所述第一卷绕起始端相对设置，所述绝缘件的至少一部分设置于所述第一拐角段与所述第一卷绕起始端之间。
  3. 根据权利要求2所述的电极组件，其特征在于，所述隔膜包括位于所述第一极片两侧的第一隔膜和第二隔膜；
    所述绝缘件绕过所述第一卷绕起始端，且所述绝缘件的两端分别与所述第一隔膜和所述第二隔膜连接。
  4. 根据权利要求3所述的电极组件，其特征在于，所述第二极片的最内圈包括第一平直段和第二平直段，所述第一拐角段连接所述第一平直段和所述第二平直段，所述第一平直段、所述第一拐角段和所述第二平直段环绕所述第一卷绕起始端的至少部分，所述绝缘件包括沿所述第二极片的卷绕方向依次设置的第一段、第二段和第三段，所述第一段设置于所述第一平直段与所述第一隔膜之间，所述第二段设置于所述第一拐角段与所述第一卷绕起始端之间，所述第三段设置于所述第二平直段与所述第二隔膜之间。
  5. 根据权利要求3所述的电极组件，其特征在于，所述绝缘件包括：第一绝缘件，所述第一绝缘件连接于所述第一隔膜和第二隔膜。
  6. 根据权利要求5所述的电极组件，其特征在于，所述第一绝缘件包括：第一基材层和第一胶质层，所述第一基材层通过所述第一胶质层连接于所述第一隔膜和所述第二隔膜。
  7. 根据权利要求6所述的电极组件，其特征在于，所述第一基材层的厚度为5mm-50mm。
  8. 根据权利要求6所述的电极组件，其特征在于，所述第一胶质层与所述第一隔膜或所述第二隔膜在卷绕方向上的重叠长度为0.5mm-15mm。
  9. 根据权利要求6所述的电极组件，其特征在于，所述第一胶质层粘接强度不小于0.05N/mm。
  10. 根据权利要求6所述的电极组件，其特征在于，所述第一胶质层的厚度为2μm-20μm。
  11. 根据权利要求6所述的电极组件，其特征在于，所述第一基材层构造为PP材料层、PI材料层或PET材料层。
  12. 根据权利要求6所述的电极组件，其特征在于，所述绝缘件还包括：第二绝缘 件，所述第二绝缘件连接于所述第二极片的最内圈的内表面。
  13. 根据权利要求12所述的电极组件，其特征在于，所述第二绝缘件包括：第二胶质层，所述第二胶质层连接于所述第二极片的最内圈的内表面。
  14. 根据权利要求13所述的电极组件，其特征在于，所述第二胶质层的厚度为2μm-20μm。
  15. 根据权利要求13所述的电极组件，其特征在于，所述第二胶质层在电解液中的粘接强度为0.02N/mm-0.4N/mm。
  16. 根据权利要求13所述的电极组件，其特征在于，在所述电极组件浸入电解液后，所述第二胶质层与所述第一基材层分离或所述第二胶质层溶解于所述电解液。
  17. 根据权利要求13所述的电极组件，其特征在于，在所述电极组件浸入电解液后，所述第二胶质层与所述第一基材层分离，所述第一基材层包括与所述第二胶质层连接的第一侧面和与所述第一胶质层连接的第二侧面，所述第一侧面的粗糙度小于所述第二侧面的粗糙度。
  18. 根据权利要求13所述的电极组件，其特征在于，所述第二绝缘件还包括：第二基材层，所述第二基材层通过所述第二胶质层连接于所述第二极片的最内圈的内表面。
  19. 根据权利要求18所述的电极组件，其特征在于，所述第二基材层的延展率大于所述第二极片的延展率。
  20. 根据权利要求19所述的电极组件，其特征在于，所述第二基材层的延展率为A，所述第一基材层的延展率为B，其中A大于B。
  21. 根据权利要求12所述的电极组件，其特征在于，所述第一绝缘件和所述第二绝缘件之间还设置有第三胶质层，在所述电极组件浸入电解液后，所述第三胶质层溶解于所述电解液，以使所述第一绝缘件和所述第二绝缘件分离。
  22. 根据权利要求21所述的电极组件，其特征在于，所述第三胶质层为亚克力胶层或橡胶层。
  23. 根据权利要求1所述的电极组件，其特征在于，所述第二极片朝向所述第一卷绕起始端的一侧设置有无活性物质的避空区，所述避空区适于至少部分容纳所述绝缘件。
  24. 根据权利要求1所述的电极组件，其特征在于，所述第一极片为负极片，所述第二极片为正极片。
  25. 一种电芯，其特征在于，包括权利要求1-24中任一项所述的电极组件。
  26. 一种用电设备，其特征在于，包括权利要求25所述的电芯。
PCT/CN2024/100768 2023-07-10 2024-06-21 电极组件、电芯和用电设备 Ceased WO2025011306A1 (zh)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN205828571U (zh) * 2016-06-06 2016-12-21 东莞新能源科技有限公司 卷绕式电芯
US20220255081A1 (en) * 2019-12-25 2022-08-11 Murata Manufacturing Co., Ltd. Secondary battery, electronic device, and power tool
CN219286491U (zh) * 2022-12-29 2023-06-30 宁德时代新能源科技股份有限公司 电池单体、电池及用电装置
CN219321579U (zh) * 2023-03-15 2023-07-07 中创新航科技集团股份有限公司 一种电池
CN116565342A (zh) * 2023-07-10 2023-08-08 宁德新能源科技有限公司 电极组件、电芯和用电设备

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102005616B (zh) * 2010-10-12 2013-06-05 深圳市豪鹏科技有限公司 电池
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Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN205828571U (zh) * 2016-06-06 2016-12-21 东莞新能源科技有限公司 卷绕式电芯
US20220255081A1 (en) * 2019-12-25 2022-08-11 Murata Manufacturing Co., Ltd. Secondary battery, electronic device, and power tool
CN219286491U (zh) * 2022-12-29 2023-06-30 宁德时代新能源科技股份有限公司 电池单体、电池及用电装置
CN219321579U (zh) * 2023-03-15 2023-07-07 中创新航科技集团股份有限公司 一种电池
CN116565342A (zh) * 2023-07-10 2023-08-08 宁德新能源科技有限公司 电极组件、电芯和用电设备

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