WO2024041080A1 - 卷芯和电池 - Google Patents

卷芯和电池 Download PDF

Info

Publication number
WO2024041080A1
WO2024041080A1 PCT/CN2023/098034 CN2023098034W WO2024041080A1 WO 2024041080 A1 WO2024041080 A1 WO 2024041080A1 CN 2023098034 W CN2023098034 W CN 2023098034W WO 2024041080 A1 WO2024041080 A1 WO 2024041080A1
Authority
WO
WIPO (PCT)
Prior art keywords
pole piece
area
empty foil
foil area
winding core
Prior art date
Application number
PCT/CN2023/098034
Other languages
English (en)
French (fr)
Inventor
姚怡鑫
张文轩
张洪雷
李俊义
Original Assignee
珠海冠宇电池股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 珠海冠宇电池股份有限公司 filed Critical 珠海冠宇电池股份有限公司
Publication of WO2024041080A1 publication Critical patent/WO2024041080A1/zh

Links

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
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—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
    • 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 disclosure relates to the field of battery technology, and in particular, to a core and a battery.
  • the battery is composed of a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte. Since the electrolyte is an organic flammable substance and the positive electrode material has poor thermal stability, when the nail penetration test is performed, a short circuit occurs instantaneously between the positive and negative electrodes of the battery. The short circuit generates a large amount of Joule heat, when the heat is accumulated to a certain extent, it will trigger a chemical reaction and produce chemical heat. The accumulation of heat will cause thermal runaway. In severe cases, it will cause the battery to catch fire or even explode.
  • the present disclosure aims to solve the safety problems of existing batteries.
  • a first aspect of the present disclosure provides a winding core, including a first pole piece and a second pole piece arranged in a stack, and the first pole piece extends from the head end of the first pole piece to the The tail end of the first pole piece is wound, and the second pole piece is wound from the head end of the second pole piece to the tail end of the second pole piece; the tail end of the first pole piece is the An empty foil area, the tail end of the second pole piece is the second empty foil area; the winding core includes a first bending area arranged on the outermost side of the winding core, and the tail end of the first pole piece The end and the tail end of the second pole piece are both located in the first bending area, and the projections of the first empty foil area and the second empty foil area along the thickness direction of the core do not exceed The first bending zone.
  • the size range of the first empty foil area along the winding direction is 0.1mm to ⁇ T/2+8mm, where T is the thickness of the winding core.
  • the size of the second empty foil area along the winding direction ranges from 0.1 mm to 10 mm.
  • the first pole piece includes a first current collector and a first active material layer, and at the location of the first empty foil area, both sides of the first current collector are not coated with the third an active material layer.
  • the first pole piece further includes an undercoat layer, the undercoat layer is located between the first current collector and the first active material layer.
  • an insulating protective layer is provided on the first pole piece located on the outermost ring of the winding core, and the insulating protective layer is provided on a side surface of the first current collector facing away from the first active material layer, And the insulating protective layer extends to the tail end of the first empty foil area.
  • the first pole piece sequentially forms a third empty foil area, a first pole piece double-sided coating area, a first pole piece single-sided coating area and a first empty foil area along the winding direction.
  • the second pole piece sequentially forms a fourth empty foil area, a second pole piece single-sided coating area, a second pole piece double-sided coating area and a second empty foil area along the winding direction.
  • the projection of the intersection of the double-sided coating area of the second pole piece and the second empty foil area covers the single-sided coating area of the first pole piece and the The projection of the intersection of the first empty foil area.
  • first empty foil area extends from the second empty foil area along the winding direction.
  • the distance between the junction of the second pole piece double-sided empty foil area and the second empty foil area and the first end surface is greater than or equal to T/2mm and less than or equal to T/2+8mm, where , the first end surface is a surface formed by extending the most prominent point of the bending area of the winding core along the thickness direction of the winding core, and T is the thickness of the winding core.
  • the winding core also includes a first pole tab and a second pole tab, the first pole tab is arranged in the third empty foil area, and the second pole tab is arranged in the fourth empty foil area, Along the thickness direction of the winding core, the projections of the first tab and the second tab do not overlap.
  • the core also includes an insulating layer, the insulating layer includes a first insulating layer, a second insulating layer, a third insulating layer, a fourth insulating layer, a fifth insulating layer, a sixth insulating layer and a seventh insulating layer.
  • the fifth insulation layer covers the surface of the first pole
  • the sixth insulation layer covers the surface of the second pole
  • the seventh insulation layer covers the second pole piece and the third pole piece.
  • the first end of the three empty foil areas is opposite to the position where the fourth insulating layer covers the junction of the third empty foil area and the double-sided coating area of the first pole piece, and the third insulating layer covers the The second insulating layer covers the single-sided coating area of the first pole piece and the first empty foil area at the intersection of the double-sided coating area of the first pole piece and the single-sided coating area of the first pole piece.
  • the insulating protective layer is provided on the first pole piece of the outermost ring of the winding core.
  • first insulating layer extends toward the first bending area, and the projection of the first insulating layer along the thickness direction of the winding core covers the first bending area along the direction of the winding core. Thickness direction projection.
  • first pole piece and the second pole piece have opposite polarities, the first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.
  • the second pole piece includes a second current collector and a second active material layer, and at the location of the second empty foil area, both side surfaces of the second current collector are not coated with the third active material layer. Two active material layers.
  • the winding core further includes a diaphragm disposed between the first pole piece and the second pole piece, and the diaphragm is wound from the first end of the diaphragm to the tail end of the diaphragm.
  • the rear end of the diaphragm exceeds the rear end of the second empty foil area.
  • the wound separator has two tail ends, and the two tail ends wrap the tail end of the second empty foil area.
  • a second aspect of the present disclosure provides a battery, including a casing and a winding core as described in the first aspect, and the winding core is packaged in the casing.
  • the first empty foil area at the tail of the first pole piece and the second empty foil area at the tail of the second pole piece are arranged in the first bending area, and the first empty foil area and The projection of the second empty foil area along the thickness direction of the core does not exceed the first bending area, realizing that both the first empty foil area and the second empty foil area are located in the first bending area, but the first empty foil area and The second empty foil area does not bypass the first bending area, so that the nail penetration rate at different positions of the winding core is more consistent, avoiding the problem of inconsistent nail penetration rates at different positions, which is beneficial to improving the safety performance of the battery.
  • neither the first empty foil area nor the second empty foil area located at the end of the core does not bypass the first bending area, which reduces the size of the empty foil area that does not provide capacity, which is beneficial to improving the energy density of the battery
  • the two empty foil areas at the end of the core are both located in the first bending area.
  • the risk of burrs formed by cutting at the end of the core piercing the separator of the core is smaller. It can effectively reduce the short circuit points of the core, thereby improving the self-discharge consistency of the core.
  • Figure 1 is a schematic structural diagram of a winding core provided in an embodiment of the present disclosure.
  • Figure 2 is a schematic structural diagram of the first pole piece provided in an embodiment of the present disclosure.
  • Figure 3 is a schematic structural diagram of the second pole piece provided in an embodiment of the present disclosure.
  • Figure 4 is a schematic diagram of the nail-piercing structure of the winding core provided in an embodiment of the present disclosure.
  • Figure 5 is a schematic diagram of the nail-piercing structure of a winding core with conventional structural design in the prior art.
  • the empty aluminum foil at the end of the positive electrode sheet is pre-processed, such as coating an insulating layer on the empty aluminum foil at the end of the positive electrode sheet, etc.
  • the pretreated empty aluminum foil at the rear it is very easy to cause contact between the aluminum foil and the negative active material layer, causing the battery to catch fire.
  • the probability of contact between the aluminum foil and the negative active material layer is significantly reduced, and the nail penetration rate is significantly improved.
  • the empty aluminum foil at the end of the positive electrode sheet does not contain the positive electrode active material layer on both sides. This empty aluminum foil will occupy the space inside the battery core and does not provide capacity, which will affect the energy density of the battery, making it impossible to balance the safety and energy of the battery. density.
  • embodiments of the present disclosure provide a winding core, which includes a first pole piece 100 , a second pole piece 200 , and a winding core disposed between the first pole piece 100 and the second pole piece 200 . Between the diaphragm 300, the first pole piece 100 and the second pole piece 200 have opposite polarities.
  • the first pole piece 100, the separator 300 and the second pole piece 200 are stacked and wound from the beginning end to the tail end to form a winding core.
  • the first pole piece 100 is rolled from the head end of the first pole piece 100 to the tail end of the first pole piece 100
  • the second pole piece 200 is rolled from the head end of the second pole piece 200 to the tail end of the second pole piece 200 Winding, the separator 300 is wound from the first end of the separator 300 to the tail end of the separator 300 .
  • the first pole piece 100 includes a first current collector 110 and a first active material layer 120 .
  • the first active material layer 120 is coated on the surface of the first current collector 110 .
  • the tail end of the first pole piece 100 is the first current collector 110 Both side surfaces of the first empty foil area 130 are not coated with the first active material layer 120 .
  • the second pole piece 200 includes a second current collector 210 and a second active material layer 220.
  • the second active material layer 220 is coated on the surface of the second current collector 210.
  • the tail end of the second pole piece 200 is the second current collector 210.
  • the second empty foil area 230 is not coated with the second active material layer 220 on both sides of the surface.
  • the winding core includes a first bending area 400 disposed on the outermost side of the winding core.
  • the tail end of the first pole piece 100 and the tail end of the second pole piece 200 are both located in the first bending area 400, and the first empty space
  • the projections of the foil area 130 and the second empty foil area 230 along the thickness direction of the roll core do not exceed the first bending area 400 .
  • the first empty foil area 130 at the end of the first pole piece 100 and the second empty foil area 230 at the end of the second pole piece 200 are arranged in the first bending area 400, and
  • the projections of the first empty foil area 130 and the second empty foil area 230 along the thickness direction of the roll core do not exceed the first bending area 400, so that the first empty foil area 130 and the second empty foil area 230 are both located in the first bending area 400.
  • the bending area 400, but the first empty foil area 130 and the second empty foil area 230 do not bypass the first bending area 400, so that the nail penetration rate at different positions of the core is more consistent, and the nail penetration rate at different positions is avoided.
  • the first empty foil area 130 and the second empty foil area 230 located at the end of the core do not bypass the first bending area 400, which reduces the size of the empty foil area that does not provide capacity, which is beneficial to increasing the energy of the battery.
  • Density, and the two empty foil areas 130, 230 at the end of the roll core are both located in the first bending area 400.
  • the burrs formed by cutting at the end of the roll core pierce the roll core.
  • the diaphragm 300 has less risk and can effectively reduce the short circuit points of the winding core, thereby improving the self-discharge consistency of the winding core.
  • the first end of the first pole piece 100 and the second pole piece 200 refers to the end where the first pole piece 100 and the second pole piece 200 start to wind during the winding process of the winding core.
  • the tail end of the piece 200 refers to the end at which the first pole piece 100 and the second pole piece 200 finish winding during the winding process of the winding core.
  • the surface formed by the most prominent point of the bending area of the winding core extending along the thickness direction of the winding core is the first end surface (ie, the vertical dotted line in Figure 1), and the first bending area 400 is the winding core.
  • the bending area is an arc-shaped surface tangent to the first end surface, the first empty foil area 130 and the second empty foil area 230 are arranged close to the first end surface, and the first empty foil area 130 and the second empty foil area 230 are located at the first end surface.
  • a bending area 400 is an arc-shaped surface tangent to the first end surface, the first empty foil area 130 and the second empty foil area 230 are arranged close to the first end surface, and the first empty foil area 130 and the second empty foil area 230 are located at the first end surface.
  • the size range of the first empty foil area 130 along the winding direction is 0.1mm to ⁇ T/2+8mm, where T is the thickness of the winding core, and That is, in Figure 2, 0.1mm ⁇ L1 ⁇ T ⁇ /2+8mm, thus ensuring that the projection of the first empty foil area 130 along the thickness direction of the winding core is located in the first bending area 400, but the first empty foil area
  • the projection of 130 along the thickness direction of the roll core does not exceed the first bending area 400, which ensures that the energy density of the battery core can be further improved on the premise of improving the safety performance of the battery.
  • the size range of the second empty foil area 230 along the winding direction is 0.1 mm to 10 mm, that is, in FIG. 3, 0.1 mm ⁇ L2 ⁇ 10 mm, Therefore, it can be ensured that the projection of the second empty foil area 230 along the thickness direction of the winding core is located in the first bending area 400 , but the projection of the second empty foil area 230 along the thickness direction of the winding core does not exceed the first bending area 400 , ensuring that the energy density of the battery core is further improved while improving the safety performance of the battery.
  • the first pole piece 100 further includes an undercoat layer 140 .
  • the undercoat layer 140 is located between the first current collector 110 and the first active material layer 120 , and the surface of the first current collector 110 only needs After the first active material layer 120 is coated, the undercoat layer 140 is disposed between the first active material layer 120 and the first current collector 110 . Therefore, disposing the undercoat layer 140 between the first current collector 110 and the first active material layer 120 is beneficial to improving the performance of the nail penetration test, thereby benefiting Improve the safety of the roll core.
  • the material of the undercoat layer 140 is not further limited, and those skilled in the art can select it according to the actual situation.
  • the undercoat layer 140 can be composed of inorganic materials, adhesives and conductive agents.
  • the mass percentage of inorganic materials is 60% to 99%, the mass percentage of binders is 0.5% to 20%, and the mass percentage of conductive agents is 0.5% to 20%.
  • the inorganic materials can be selected from alumina, boehmite, and phosphoric acid.
  • the binder can be selected from polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polypropylene, polyethylene , one or more of polytetrafluoroethylene, polystyrene, modified polyvinylidene fluoride, styrene-butadiene rubber, carboxymethyl cellulose, polyacrylic acid, polyacrylonitrile, polymethacrylate and polyacrylate.
  • the conductive agent can be selected from one or a combination of conductive carbon black, carbon nanotubes, graphen
  • the thickness of the undercoat layer 140 may range from 1 ⁇ m to 30 ⁇ m. Those skilled in the art can set the specific thickness of the undercoat layer 140 according to actual conditions.
  • the first pole piece 100 also includes an insulating protective layer 150 .
  • the first pole piece 100 is located on the outermost ring of the winding core.
  • the first pole piece 100 is located on the outermost ring of the winding core.
  • the insulating protective layer 150 is disposed on the side surface of the first current collector 110 facing away from the first active material layer 120 , and the insulating protective layer 150 extends to the tail end of the first empty foil area 130 , that is, located on the roll
  • the first pole piece 100 in the outermost ring of the core is provided with an insulating protective layer 150 on the side surface facing the outside of the core, and is provided with a first active layer opposite to the second active material layer 220 on the side surface facing the inside of the core.
  • the insulating protective layer 150 is provided on the first pole piece 100.
  • the insulating protective layer 150 can prevent the first current collector 110 and the second active material layer 220 from contacting, thereby helping to greatly improve the safety performance of the winding core.
  • the material of the insulating protective layer 150 is not further limited, and those skilled in the art can select it according to the actual situation.
  • the insulating protective layer 150 can be composed of inorganic materials and adhesives.
  • the mass percentage of inorganic materials is 50% to 99.5%, and the mass percentage of binders is 0.5% to 50%.
  • the inorganic material may be selected from alumina, boehmite, magnesium oxide, magnesium hydroxide, titanium oxide, titanium dioxide, tin oxide, calcium oxide, calcium hydroxide, nickel oxide, zinc oxide, zirconium dioxide, hafnium dioxide, One or a combination of silicon, ceria, barium sulfate, etc., and the D90 of the inorganic material is less than 40 ⁇ m, and the powder resistivity of the inorganic material is greater than 104 ⁇ *cm.
  • the binder can be selected from polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polypropylene, polyethylene, polytetrafluoroethylene, polystyrene, modified polyvinylidene fluoride, styrene-butadiene rubber, carboxymethyl fiber
  • polyacrylate polyacrylic acid, polyacrylonitrile, polymethacrylate and polyacrylate.
  • the thickness of the insulating protective layer 150 may range from 1 ⁇ m to 50 ⁇ m. Those skilled in the art can set the specific thickness of the insulating protective layer 150 according to actual conditions.
  • the first pole piece 100 sequentially forms a third empty foil area, a first pole piece double-sided coating area, and a first pole piece single-sided coating along the winding direction (that is, from the beginning end to the tail end). area (neither labeled in the figure) and the first empty foil area 130.
  • the third empty foil area means that the two opposite surfaces of the first current collector 110 are not covered with any substance. That is, the third empty foil area means that the two opposite surfaces of the first current collector 110 are not covered with the first active material layer.
  • the double-sided coating area of the first pole piece refers to the two opposite surfaces of the first current collector 110 being covered with the primer layer 140 and the first active material layer 120; the single-sided coating area of the first pole piece refers to the first pole piece single-sided coating area.
  • One of the two opposite surfaces of the current collector 110 is covered with the base coating 140 and the first active material layer 120, and the other surface is only covered with the insulating protective layer 150; the first empty foil area 130 refers to the first current collector
  • One of the two opposite surfaces of 110 is not covered with any substance, and the other surface is only covered with an insulating protective layer 150 .
  • the second pole piece 200 sequentially forms a fourth empty foil area, a second pole piece single-sided coating area, and a second pole piece double-sided coating area along the winding direction (none of which are shown in the figure). marked) and the second empty foil area 230.
  • the fourth empty foil area refers to the two opposite surfaces of the second current collector 210 that are not covered with the second active material layer 220; the second pole piece single-sided coating area refers to the two opposite surfaces of the second current collector 210.
  • One surface is covered with the second active material layer 220, and the other surface is not covered with the second active material layer 220; the double-sided coating area of the second pole piece means that both opposite surfaces of the second current collector 210 are covered with the second active material layer 220.
  • Material layer 220; the second empty foil area 230 means that the two opposite surfaces of the second current collector 210 are not covered with the second active material layer 220.
  • the projection of the intersection of the double-sided empty foil area of the second pole piece and the second empty foil area 230 covers the projection of the intersection of the single-sided coating area of the first pole piece and the first empty foil area 130 , that is, the distance between the intersection of the double-sided empty foil area of the second pole piece and the second empty foil area 230 and the first end surface is greater than or equal to the intersection of the single-sided coating area of the first pole piece and the first empty foil area 130 distance from the first end surface, so the first empty foil area 130 also extends out of the second empty foil area 230 along the winding direction, which is beneficial to further improving the safety performance of the winding core.
  • the distance between the intersection of the double-sided empty foil area of the second pole piece and the second empty foil area 230 and the first end face can set according to the actual situation, as well as the distance between the single-sided coating area of the first pole piece and the first empty foil area.
  • the distance between the junction of the foil area 130 and the first end face is greater than Or equal to T/2, and less than or equal to T/2+8mm, thus ensuring the overall flatness of the roll core and improving the performance of the roll core.
  • the winding core also includes a first pole tab 500 and a second pole tab 600.
  • the first pole tab 500 is connected to the first pole piece 100
  • the second pole tab 600 is connected to the second pole piece 200, along the thickness direction of the winding core. , the projections of the first tab 500 and the second tab 600 do not overlap.
  • the first pole tab 500 may be disposed in the third empty foil area
  • the second pole tab 600 may be disposed in the fourth empty foil area.
  • the core also includes an insulating layer 700, which can further protect the core and avoid short circuits.
  • the insulating layer 700 includes a first insulating layer 710 , a second insulating layer 720 , a third insulating layer 730 and a fourth insulating layer 740 .
  • the first insulating layer 710 covers the side surface of the first empty foil area 130 facing the outside of the winding core, and the first insulating layer 710 covers the side surface of the insulating protective layer 150 facing away from the first current collector 110 .
  • the first insulating layer 710 710 extends toward the first bending area 400, and the projection of the first insulating layer 710 along the thickness direction of the roll core can cover the projection of the first bending area 400 along the thickness direction of the roll core; the second insulating layer 720 covers the first The intersection of the single-sided coating area of the pole piece and the first empty foil area 130; the third insulating layer 730 covers the intersection of the double-sided coating area of the first pole piece and the single-sided coating area of the first pole piece; the fourth The insulating layer 740 covers the intersection between the third empty foil area and the double-sided coating area of the first pole piece; thus, the intersection between the single-sided coating area of the first pole piece and the first empty foil area 130 can be avoided, and The active material burrs at the junction of the double-sided coating area of the first pole piece and the single-sided coating area of the first pole piece pierce the diaphragm 300 or the housing, causing safety risks such as short circuit or liquid leakage.
  • the insulation layer 700 also includes a fifth insulation layer 750 , a sixth insulation layer 760 and a seventh insulation layer 770 .
  • the fifth insulation layer 750 covers the surface of the first pole tab 500; the sixth insulation layer 760 covers the surface of the second pole tab 600; the positions of the second pole piece 200 opposite to the first end of the third empty foil area are covered with
  • the seventh insulating layer 770 can thereby prevent burrs on the edges of the first tab 500, the second tab 600 and the third empty foil area from piercing the diaphragm 300 and causing a short circuit.
  • the material of the insulating layer 700 is not further limited. Those skilled in the art can select it according to the actual situation.
  • the material of the insulating layer 700 can be selected from acrylic, rubber, hot melt adhesive, etc. one or a combination of several.
  • the first pole piece 100 is a positive pole piece
  • the second pole piece 200 is a negative pole piece. Therefore, while improving the energy density of the battery and improving the pass rate of the nail penetration test, it is also possible to avoid rolling After the core is wound, it forms a galvanic cell with the outer shell, causing corrosion.
  • the material of the first pole piece 100 and the second pole piece 200 can be one or more of metal foils such as aluminum foil, copper foil, nickel foil, gold foil, and platinum foil.
  • the first pole piece 100 is made of aluminum foil
  • the second pole piece 200 is made of copper foil
  • the first pole tab 500 is also made of aluminum foil
  • the second pole tab 600 is made of copper foil.
  • the rear end of the diaphragm 300 exceeds the rear end of the second empty foil area 230 .
  • the wound separator 300 has two tail ends, and these two tail ends wrap the tail end of the second empty foil area 230, thereby further improving the safety of the winding core.
  • the size of the tail end of the diaphragm 300 beyond the second empty foil area 230 is not further limited. Those skilled in the art can set it according to the actual situation. For example, the tail end of the diaphragm 300 exceeds the second empty foil area. The size of the trailing end of area 230 is greater than or equal to 1 mm.
  • a second aspect of the embodiments of the present disclosure provides a battery, which includes a casing and a winding core as described in the first aspect, and the winding core is packaged in the casing.
  • the housing is not further limited, and those skilled in the art can select it according to the actual situation.
  • the housing can be an aluminum-plastic film housing.
  • the first empty foil area 130 at the tail of the first pole piece 100 and the second empty foil area 230 at the tail of the second pole piece 200 are arranged in the first bending area 400, and the first The projections of the empty foil area 130 and the second empty foil area 230 along the thickness direction of the roll core do not exceed the first bending area 400, realizing that the first empty foil area 130 and the second empty foil area 230 are both located in the first bending area. area 400, but neither the first empty foil area 130 nor the second empty foil area 230 bypass the first bending area 400, so that the nailing pass rate at different positions of the core is more consistent, and the nailing pass rate at different positions is avoided to be inconsistent. problem, which is beneficial to improving the safety performance of the battery.
  • first empty foil area 130 and the second empty foil area 230 located at the end of the core do not bypass the first bending area 400, which reduces the size of the empty foil area that does not provide capacity, which is beneficial to increasing the energy of the battery.
  • Density, and the two empty foil areas 130, 230 at the end of the roll core are both located in the first bending area 400.
  • the burrs formed by cutting at the end of the roll core pierce the roll core.
  • the diaphragm 300 has less risk and can effectively reduce the short circuit points of the winding core, thereby improving the self-discharge consistency of the winding core.
  • the embodiment of the present disclosure adopts the structure of the winding core in FIG. 4 .
  • Comparative Example 1 is a winding core designed with a conventional structure, that is, the winding core structure in Figure 5 is adopted.
  • the tail end of the first empty foil area 130 bypasses the first bending area 400 and is located in the straight area.
  • Comparative Example 2 adopts the structure of the winding core in FIG. 4 , but the undercoat layer 140 and the insulating protective layer 150 are not provided on the first current collector 110 .
  • Comparative Example 3 adopts the structure of the winding core in Figure 4, but the undercoat layer 140 and the insulating protective layer 150 are not provided on the first current collector 110, and the tail end of the first empty foil area 130 bypasses the first bending area 400, And located in the straight area.
  • a nail penetration test was performed on the winding cores in the embodiments of the present disclosure and Comparative Examples 1 to 3.
  • the nail penetration test conditions were to use 3mm steel nails at position A and position B (refer to Figures 4 and 5 for these two positions), Pierce the battery at a speed of 30mm/s.
  • Judgment criteria If the battery does not smoke or catch fire, it is judged to be passed. If it smokes or catches fire, it is judged to have failed. The test results are shown in Table 1.
  • the conventionally structured core used in Comparative Example 1 was tested at position A for 50pcs, smoke and fire occurred at 16pcs, and the pass rate was 68%; when 50pcs was tested at position B, smoke and fire occurred at 0pcs, and the pass rate was 100%. It can be seen that there is a significant difference in the pass rate of the nail penetration test between the core of the conventional structure at position A and position B.
  • the charge and discharge voltage range of the core of this conventional structure is 4.45V to 3V, the capacity is 5000mAh, and the energy density is 712Wh/L. .
  • the core in the embodiment of the present disclosure is tested at position A for 50pcs, and smoke and fire are emitted at 0pcs, and the pass rate is 100%; when 50pcs is tested at position B, smoke and fire are emitted at 0pcs, and the pass rate is 100%. It can be seen that the pass rate of the nail penetration test at positions A and B has been significantly improved.
  • the charge and discharge voltage range of the core in the embodiment of the present disclosure is 4.45V to 3V, the capacity is 5000mAh, and the energy density is 720Wh/L. Compared with conventionally structured cores (for example, lithium-ion batteries), the energy density is increased by 8Wh/L.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Secondary Cells (AREA)
  • Connection Of Batteries Or Terminals (AREA)

Abstract

本公开提供了一种卷芯和电池，卷芯包括层叠设置的第一极片和第二极片第一极片从第一极片的首端向第一极片的尾端卷绕，第二极片从第二极片的首端向第二极片的尾端卷绕；第一极片的尾端为第一空箔区；第二极片的尾端为第二空箔区；卷芯包括设置于卷芯的最外侧的第一弯折区，第一极片的尾端和第二极片的尾端均位于第一弯折区，且第一空箔区和第二空箔区沿卷芯的厚度方向的投影均不超过第一弯折区。本公开解决了电池安全性和能量密度无法同时兼顾的问题。

Description

卷芯和电池 技术领域
本公开涉及电池技术领域，具体而言，涉及一种卷芯和电池。
背景技术
电池自商业化以来，因其优异的电化学性能、自放电小、可快速充放电、高能量密度等特点在便携式电子产品、新能源汽车等领域被广泛应用。
电池由正极片、负极片、隔膜和电解液等组成，由于电解液是有机易燃体，正极材料热稳定性差，当进行穿钉测试时，电池正负极之间瞬间发生短路，短路产生大量焦耳热，当热量积蓄到一定程度时会引发化学反应，产生化学热，热量积累会引起热失控，严重时会引起电池起火甚至产生爆炸。
发明内容
本公开旨在解决现有的电池的安全性的问题。
为解决上述问题，本公开第一方面提供了一种卷芯，包括层叠设置的第一极片和第二极片，所述第一极片从所述第一极片的首端向所述第一极片的尾端卷绕，所述第二极片从所述第二极片的首端向所述第二极片的尾端卷绕；所述第一极片的尾端为第一空箔区，所述第二极片的尾端为第二空箔区；所述卷芯包括设置于所述卷芯的最外侧的第一弯折区，所述第一极片的尾端和所述第二极片的尾端均位于所述第一弯折区，且所述第一空箔区和所述第二空箔区沿所述卷芯的厚度方向的投影均不超过所述第一弯折区。
进一步地，所述第一空箔区沿卷绕方向的尺寸范围为0.1mm至πT/2+8mm，其中，T为所述卷芯的厚度。
进一步地，所述第二空箔区沿卷绕方向的尺寸范围为0.1mm至10mm。
进一步地，所述第一极片包括第一集流体和第一活性物质层，在所述第一空箔区所在位置处，所述第一集流体的双侧表面均未涂敷所述第一活性物质层。
进一步地，所述第一极片还包括底涂层，所述底涂层位于所述第一集流体和所述第一活性物质层之间。
进一步地，位于所述卷芯的最外圈的第一极片上还设置有绝缘保护层，所述绝缘保护层设置在所述第一集流体背离所述第一活性物质层的一侧表面，且所述绝缘保护层延伸至所述第一空箔区的尾端。
进一步地，所述第一极片沿卷绕方向依次形成第三空箔区、第一极片双面涂敷区、第一极片单面涂敷区和第一空箔区。
进一步地，所述第二极片沿卷绕方向依次形成第四空箔区、第二极片单面涂敷区、第二极片双面涂敷区和第二空箔区。
进一步地，沿所述卷芯的厚度方向，所述第二极片双面涂敷区和所述第二空箔区的交接处的投影覆盖所述第一极片单面涂敷区和所述第一空箔区的交接处的投影。
进一步地，所述第一空箔区沿卷绕方向伸出所述第二空箔区。
进一步地，所述第二极片双面空箔区和所述第二空箔区的交接处距离第一端面的间距范围大于或等于T/2mm，且小于或等于T/2+8mm，其中，所述第一端面为所述卷芯的弯折区域最突出的点沿所述卷芯的厚度方向延伸形成的面，T为所述卷芯的厚度。
进一步地，该卷芯还包括第一极耳和第二极耳，所述第一极耳设置于所述第三空箔区，所述第二极耳设置于所述第四空箔区，沿所述卷芯的厚度方向，所述第一极耳和所述第二极耳的投影不重叠。进一步地，该卷芯还包括绝缘层，所述绝缘层包括第一绝缘层、第二绝缘层、第三绝缘层、第四绝缘层、第五绝缘层、第六绝缘层和第七绝缘层，所述第五绝缘层覆盖所述第一极耳的表面，所述第六绝缘层覆盖所述第二极耳的表面，所述第七绝缘层覆盖所述第二极片与所述第三空箔区的首端相对的位置，所述第四绝缘层覆盖所述第三空箔区和所述第一极片双面涂敷区的交接处，所述第三绝缘层覆盖所述第一极片双面涂敷区和所述第一极片单面涂敷区的交接处所述第二绝缘层覆盖所述第一极片单面涂敷区和所述第一空箔区的交接处，所述第一绝缘层覆盖所述第一空箔区在朝向所述卷芯的外部的一侧表面以及绝缘保护层背离所述第一极片的第一集流体的一侧表面中的至少一个表面，所述绝缘保护层设置在所述卷芯的最外圈的第一极片上。
进一步地，所述第一绝缘层朝所述第一弯折区延伸，并且所述第一绝缘层沿所述卷芯的厚度方向的投影覆盖所述第一弯折区沿所述卷芯的厚度方向的投影。
进一步地，所述第一极片和所述第二极片的极性相反，所述第一极片为正极片，所述第二极片为负极片。
进一步地，所述第二极片包括第二集流体和第二活性物质层，在所述第二空箔区所在位置处，所述第二集流体的双侧表面均未涂敷所述第二活性物质层。
进一步地，该卷芯还包括设置在所述第一极片和所述第二极片之间的隔膜，所述隔膜从所述隔膜的首端向所述隔膜的尾端卷绕。
进一步地，所述隔膜的尾端超出所述第二空箔区的尾端。
进一步地，卷绕完成的隔膜具有两个尾端，所述两个尾端包裹所述第二空箔区的尾端。
本公开第二方面提供了一种电池，包括壳体和如第一方面所述的卷芯，所述卷芯封装于所述壳体内。
本公开所述的卷芯和电池，通过使第一极片尾部的第一空箔区和第二极片尾部的第二空箔区设置在第一弯折区，且第一空箔区和第二空箔区沿卷芯的厚度方向的投影均不超过第一弯折区，实现了第一空箔区和第二空箔区均位于第一弯折区，但第一空箔区和第二空箔区均不绕过第一弯折区，使卷芯不同位置穿钉通过率更趋于一致，避免不同位置穿钉通过率不一致的问题，有利于提高了电池的安全性能。此外，位于卷芯尾部的第一空箔区和第二空箔区均不绕过第一弯折区，减小了不提供容量的空箔区的尺寸，有利于提高电池的能量密度，并且卷芯尾部的两个空箔区均位于第一弯折区，与卷芯尾部的空箔区位于平面相比，卷芯尾部受裁切形成的毛刺刺穿卷芯的隔膜的风险更小，能够有效减小卷芯的短路点，从而提升卷芯的自放电一致性。
附图说明
图1为本公开实施例中提供的卷芯的结构示意图。
图2为本公开实施例中提供的第一极片的结构示意图。
图3为本公开实施例中提供的第二极片的结构示意图。
图4为本公开实施例中提供的卷芯的穿钉结构示意图。
图5为现有技术中常规结构设计的卷芯的穿钉结构示意图。
附图标记说明：
100-第一极片；110-第一集流体；120-第一活性物质层；130-第一空箔区；140-底涂层；150-绝缘保护层；200-第二极片；210-第二集流体；220-第二活性物质层；230-第二空箔区；300-隔膜；400-第一弯折区；500-第一极耳；600-第二极耳；700-绝缘层；710-第一绝缘层；720-第二绝缘层；730-第三绝缘层；740-第四绝缘层；750-第五绝缘层；760-第六绝缘层；770-第七绝缘层。
具体实施方式
下面结合附图对本公开的技术方案进行清楚、详尽地描述。在本公开的描述中，需要说明的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“垂直”、“水平”、“顶”、“底”、“内”、“外”、等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本公开和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本公开的限制。此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或 暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个所述特征。此外，在本公开的描述中，“至少一个”的含义是一个或一个以上，除非另有明确具体的限定。
在本说明书的描述中，术语“在上述实施例的基础上”的描述意指结合该实施例或示例描述的具体特征、结构、材料或特点包含于本公开的至少一个优选实施例或优选示例中。在本说明书中，对上述术语的示意性表述不一定指的是相同的实施或实例。而且，描述的具体特征、结构、材料或特点可以在任何的一个或多个实施例或示例中以合适的方式结合。
在相关技术中，为了改善电池的穿钉性能，例如，锂离子电池的穿钉性能，会对正极片尾部的空铝箔进行预处理，例如在正极片尾部的空铝箔上涂敷绝缘层等，但是当钉子从经过预处理的尾部空铝箔处刺入电芯时，极容易引发铝箔与负极活性物质层的接触，从而造成电池起火燃烧。当钉子从不含尾部空铝箔的位置刺入电芯时，引发铝箔与负极活性物质层接触的概率明显降低，穿钉通过率明显提升，虽然这种结构能够改善电池的穿钉性能，但存在电芯不同位置的安全性不一致的问题。此外，正极片尾部的空铝箔两侧均不含正极活性物质层，该空铝箔会占用电芯内部的空间，且不提供容量，会影响电池的能量密度，从而无法兼顾电池的安全性与能量密度。
结合图1至图3所示，本公开的实施例提供了一种卷芯，该卷芯包括第一极片100、第二极片200以及设置在第一极片100和第二极片200之间的隔膜300，第一极片100和第二极片200的极性相反。
第一极片100、隔膜300和第二极片200层叠设置并从首端向尾端卷绕，形成卷芯。第一极片100从第一极片100的首端向第一极片100的尾端卷绕，第二极片200从第二极片200的首端向第二极片200的尾端卷绕，隔膜300从隔膜300的首端向隔膜300的尾端卷绕。
第一极片100包括第一集流体110和第一活性物质层120，第一活性物质层120涂敷于第一集流体110的表面，第一极片100的尾端为第一集流体110的双侧表面均未涂敷第一活性物质层120的第一空箔区130。
第二极片200包括第二集流体210和第二活性物质层220，第二活性物质层220涂敷于第二集流体210的表面，第二极片200的尾端为第二集流体210的双侧表面均未涂敷第二活性物质层220的第二空箔区230。
卷芯包括设置于所述卷芯的最外侧的第一弯折区400，第一极片100的尾端和第二极片200的尾端均位于第一弯折区400，且第一空箔区130和第二空箔区230沿卷芯的厚度方向的投影均不超过第一弯折区400。
本实施例中提供的卷芯，通过使第一极片100的尾部的第一空箔区130和第二极片200的尾部的第二空箔区230设置在第一弯折区400，且第一空箔区130和第二空箔230区沿卷芯的厚度方向的投影均不超过第一弯折区400，实现了第一空箔区130和第二空箔区230均位于第一弯折区400，但第一空箔区130和第二空箔230区均不绕过第一弯折区400，使卷芯不同位置穿钉通过率更趋于一致，避免不同位置穿钉通过率不一致的问题，有利于提高了电池的安全性能。此外，位于卷芯尾部的第一空箔区130和第二空箔区230均不绕过第一弯折区400，减小了不提供容量的空箔区的尺寸，有利于提高电池的能量密度，并且卷芯尾部的两个空箔区130，230均位于第一弯折区400，与卷芯尾部的空箔区位于平面相比，卷芯尾部受裁切形成的毛刺刺穿卷芯的隔膜300的风险更小，能够有效减小卷芯的短路点，从而提升卷芯的自放电一致性。
第一极片100和第二极片200的首端是指卷芯在卷绕的过程中第一极片100和第二极片200卷绕开始的一端，第一极片100和第二极片200的尾端是指卷芯在卷绕的过程中第一极片100和第二极片200卷绕收尾的一端。
本实施例中，卷芯的弯折区域最突出的点沿卷芯的厚度方向延伸形成的面为第一端面(即图1中的竖直的虚线)，第一弯折区400为卷芯的弯折区域与第一端面相切的弧形面，第一空箔区130和第二空箔区230靠近第一端面设置，且第一空箔区130和第二空箔区230位于第一弯折区400。
在上述实施例的基础上，结合图1和图2所示，第一空箔区130沿卷绕方向的尺寸范围为0.1mm至πT/2+8mm，其中，T为卷芯的厚度，也即，图2中，0.1mm≤L1≤Tπ/2+8mm，由此，能够保证第一空箔区130沿卷芯的厚度方向的投影位于第一弯折区400，但第一空箔区130沿卷芯的厚度方向的投影不超过第一弯折区400，保证在提高电池的安全性能的前提下，进一步提高电芯的能量密度。
在上述实施例的基础上，结合图1和图3所示，第二空箔区230沿卷绕方向的尺寸范围为0.1mm至10mm，也即，图3中，0.1mm≤L2≤10mm，由此，能够保证第二空箔区230沿卷芯的厚度方向的投影位于第一弯折区400，但第二空箔区230沿卷芯的厚度方向的投影不超过第一弯折区400，保证在提高电池的安全性能的前提下，进一步提高电芯的能量密度。
结合图1和图2所示，第一极片100还包括底涂层140，底涂层140位于第一集流体110和第一活性物质层120之间，且第一集流体110的表面只要涂敷了第一活性物质层120，则第一活性物质层120和第一集流体110之间就设置有底涂层140。由此，在第一集流体110和第一活性物质层120之间设置底涂层140，有利于改善穿钉测试的性能，从而有利于 提高卷芯的安全性。
本实施例中对底涂层140的材质不做进一步地限定，本领域的技术人员可以根据实际情况进行选择，例如，底涂层140可以由无机材料、粘结剂和导电剂组成。无机材料的质量百分比为60％至99％，粘结剂的质量百分比为0.5％至20％，导电剂的质量百分比为0.5％至20％，无机材料可以选自氧化铝、勃母石、磷酸铁、磷酸锰、磷酸铁猛、磷酸铝、镍钴锰酸锂、镍钴铝酸锂、磷酸铁锂、磷酸铁钠、磷酸锰锂、磷酸锰铁锂、磷酸钒锂、磷酸钒氧锂、钒酸锂、钛酸锂、锰酸锂和镍酸锂中的一种或几种的组合；粘结剂可以选自聚偏氟乙烯、聚偏氟乙烯-六氟丙烯、聚丙烯、聚乙烯、聚四氟乙烯、聚苯乙烯、改性聚偏氟乙烯、丁苯橡胶、羧甲基纤维素、聚丙烯酸、聚丙烯腈、聚甲基丙烯酸酯和聚丙烯酸酯中的一种或几种的组合；导电剂可以选自导电炭黑、碳纳米管、石墨烯、乙炔黑等中的一种或几种的组合。
本实施例中底涂层140的厚度范围可以为1μm至30μm，本领域的技术人员可以根据实际情况设置底涂层140的具体厚度。
结合图1和图2所示，第一极片100还包括绝缘保护层150，第一极片100位于卷芯的最外圈，位于卷芯的最外圈的第一极片100上设置有绝缘保护层150，绝缘保护层150设置在第一集流体110背离第一活性物质层120的一侧表面，且绝缘保护层150延伸至第一空箔区130的尾端，也即，位于卷芯最外圈的第一极片100在朝向卷芯外部的一侧表面设置有绝缘保护层150，在朝向卷芯内部的一侧表面设置有与第二活性物质层220相对设置的第一活性物质层120，且第一空箔区130在朝向卷芯外部的一侧表面也设置有绝缘保护层150，由此，在第一极片100上设置绝缘保护层150，在进行穿钉测试时，该绝缘保护层150能够起到防止第一集流体110和第二活性物质层220相接触的作用，从而有利于大幅度提升卷芯的安全性能。
本实施例中对绝缘保护层150的材质不做进一步地限定，本领域的技术人员可以根据实际情况进行选择，例如，绝缘保护层150可以由无机材料和粘结剂组成。无机材料的质量百分比为50％至99.5％，粘结剂的质量百分比为0.5％至50％。无机材料可以选自氧化铝、勃姆石、氧化镁、氢氧化镁、氧化钛、二氧化钛、氧化锡、氧化钙、氢氧化钙、氧化镍、氧化锌、二氧化锆、二氧化铪、二氧化硅、二氧化铈和硫酸钡等中的一种或者几种的组合，且无机材料的D90小于40μm，无机材料的粉末电阻率大于104Ω*cm。粘结剂可以选自聚偏氟乙烯、聚偏氟乙烯-六氟丙烯、聚丙烯、聚乙烯、聚四氟乙烯、聚苯乙烯、改性聚偏氟乙烯、丁苯橡胶、羧甲基纤维素、聚丙烯酸、聚丙烯腈、聚甲基丙烯酸酯和聚丙烯酸酯中的一种或几种的组合。
本实施例中绝缘保护层150的厚度范围可以为1μm至50μm，本领域的技术人员可以根据实际情况设置绝缘保护层150的具体厚度。
在一实施例中，第一极片100沿卷绕方向(即从首端至尾端)依次形成第三空箔区、第一极片双面涂敷区、第一极片单面涂敷区(图中均未标示)和第一空箔区130。第三空箔区是指第一集流体110的相对两个表面均未覆盖任何物质，即，第三空箔区是指第一集流体110的相对两个表面均未覆盖第一活性物质层120；第一极片双面涂敷区是指第一集流体110的相对两个表面均覆盖有底涂层140和第一活性物质层120；第一极片单面涂敷区是指第一集流体110的相对两个表面中的一个表面覆盖有底涂层140和第一活性物质层120，另一个表面仅覆盖有绝缘保护层150；第一空箔区130是指第一集流体110的相对两个表面中的一个表面未覆盖任何物质，另一个表面仅覆盖有绝缘保护层150。
结合图1和图3所示，第二极片200沿卷绕方向依次形成第四空箔区、第二极片单面涂敷区、第二极片双面涂敷区(图中均未标示)和第二空箔区230。第四空箔区是指第二集流体210的相对两个表面均未覆盖第二活性物质层220；第二极片单面涂敷区是指第二集流体210的相对两个表面中的一个表面覆盖有第二活性物质层220，另一个表面未覆盖第二活性物质层220；第二极片双面涂敷区是指第二集流体210的相对两个表面均覆盖有第二活性物质层220；第二空箔区230是指第二集流体210的相对两个表面均未覆盖第二活性物质层220。
沿卷芯的厚度方向，第二极片双面空箔区和第二空箔区230的交接处的投影覆盖第一极片单面涂敷区和第一空箔区130的交接处的投影，也即，第二极片双面空箔区和第二空箔区230的交接处距离第一端面的间距大于或者等于第一极片单面涂敷区和第一空箔区130的交接处距离第一端面的间距，因此也使第一空箔区130沿卷绕方向伸出第二空箔区230，由此，有利于进一步提高卷芯的安全性能。
本领域的技术人员可以根据实际情况设置第二极片双面空箔区和第二空箔区230的交接处距离第一端面的间距，以及第一极片单面涂敷区和第一空箔区130的交接处距离第一端面的间距，但为了保证卷芯整体的平整度，第二极片双面空箔区和第二空箔区230的交接处距离第一端面的间距范围大于或等于T/2，且小于或等于T/2+8mm，由此，能够保证卷芯整体的平整度，有利于提升卷芯的性能。
该卷芯还包括第一极耳500和第二极耳600，第一极耳500与第一极片100连接，第二极耳600与第二极片200连接，且沿卷芯的厚度方向，第一极耳500和第二极耳600的投影不重叠。第一极耳500可以设置于第三空箔区，第二极耳600可以设置于第四空箔区。
该卷芯还包括绝缘层700，绝缘层700可以对卷芯进行进一步的防护，避免短路现象 的发生，绝缘层700包括第一绝缘层710、第二绝缘层720、第三绝缘层730和第四绝缘层740。第一绝缘层710覆盖在第一空箔区130在朝向卷芯外部的一侧表面，且第一绝缘层710覆盖在绝缘保护层150背离第一集流体110的一侧表面，第一绝缘层710朝第一弯折区400延伸，并且第一绝缘层710沿卷芯的厚度方向的投影可以覆盖第一弯折区400沿卷芯的厚度方向的投影；第二绝缘层720覆盖在第一极片单面涂敷区和第一空箔区130的交接处；第三绝缘层730覆盖在第一极片双面涂敷区和第一极片单面涂敷区的交接处；第四绝缘层740覆盖在第三空箔区和第一极片双面涂敷区的交接处；由此，能够避免第一极片单面涂敷区和第一空箔区130的交接处，以及第一极片双面涂敷区和第一极片单面涂敷区的交接处的活性物质毛刺刺穿隔膜300或壳体，造成短路或漏液等安全风险。
绝缘层700还包括第五绝缘层750、第六绝缘层760和第七绝缘层770。第五绝缘层750覆盖在第一极耳500的表面；第六绝缘层760覆盖在第二极耳600的表面；第二极片200与第三空箔区的首端相对的位置均覆盖有第七绝缘层770，由此，能够防止第一极耳500、第二极耳600和第三空箔区边缘的毛刺刺穿隔膜300，导致短路现象的发生。
本实施例中对绝缘层700的材质不做进一步地限定，本领域的技术人员可以根据实际情况进行选择，例如，绝缘层700的材质可以选自丙烯酸类、橡胶类和热熔胶类等中的一种或几种的组合。
本实施例中对上述几个绝缘层的长度不做进一步的限定，本领域的技术人员可以根据实际情况进行设置，只要能够避免由于析锂形成的锂枝晶或者裁切端口的毛刺刺穿隔膜300，而导致的短路现象即可。
在上述实施例的基础上，第一极片100为正极片，第二极片200为负极片，由此，在提升电池的能量密度和提升穿钉测试通过率的情况下，还能够避免卷芯卷绕后，与外层的壳体形成原电池，造成腐蚀。
在上述实施例中，第一极片100的材质和第二极片200的材质可以为铝箔、铜箔、镍箔、金箔和铂箔等金属箔中的一种或几种。较佳地，第一极片100的材质为铝箔，第二极片200的材质为铜箔，且第一极耳500的材质也为铝箔，第二极耳600的材质为铜箔。
本实施例中，隔膜300的尾端超出第二空箔区230的尾端。在隔膜300卷绕完成后，卷绕完成的隔膜300具有两个尾端，这两个尾端包裹第二空箔区230的尾端，由此，能够进一步提高卷芯的安全性。
本实施例中对隔膜300的尾端超出第二空箔区230的尾端的尺寸不做进一步地限定，本领域的技术人员可以根据实际情况进行设置，例如隔膜300的尾端超出第二空箔区230的尾端的尺寸大于或等于1mm。
常规结构设计的卷芯(即第一空箔区130的尾端绕过第一弯折区400，并位于平直区)的能量密度为Q，卷芯的厚度为T，第一集流体110的厚度为T1，绝缘保护层150的厚度为T2，则采用本实施例结构设计的卷芯的能量密度Q1＝T*Q/(T-T1-T2)。
本公开的实施例第二方面提供了一种电池，该电池包括壳体和如第一方面所述的卷芯，卷芯封装于壳体内。
本实施例中对壳体不作进一步地限定，本领域的技术人员可以根据实际情况选择，例如壳体为铝塑膜壳体。
本实施例提供的电池，通过使第一极片100的尾部的第一空箔区130和第二极片200的尾部的第二空箔区230设置在第一弯折区400，且第一空箔区130和第二空箔区230沿卷芯的厚度方向的投影均不超过第一弯折区400，实现了第一空箔区130和第二空箔区230均位于第一弯折区400，但第一空箔区130和第二空箔区230均不绕过第一弯折区400，使卷芯不同位置穿钉通过率更趋于一致，避免不同位置穿钉通过率不一致的问题，有利于提高了电池的安全性能。此外，位于卷芯尾部的第一空箔区130和第二空箔区230均不绕过第一弯折区400，减小了不提供容量的空箔区的尺寸，有利于提高电池的能量密度，并且卷芯尾部的两个空箔区130，230均位于第一弯折区400，与卷芯尾部的空箔区位于平面相比，卷芯尾部受裁切形成的毛刺刺穿卷芯的隔膜300的风险更小，能够有效减小卷芯的短路点，从而提升卷芯的自放电一致性。
为了对本实施例中的卷芯在安全性的改善和能量密度提升方面的作用，采用以下对比例来进一步说明。
本公开的实施例采用图4中卷芯的结构。
对比例1为常规结构设计的卷芯，也即采用图5中卷芯的结构，第一空箔区130的尾端绕过第一弯折区400，并位于平直区。
对比例2采用图4中卷芯的结构，但第一集流体110上未设置底涂层140和绝缘保护层150。
对比例3采用图4中卷芯的结构，但第一集流体110上未设置底涂层140和绝缘保护层150，且第一空箔区130的尾端绕过第一弯折区400，并位于平直区。
对本公开的实施例和对比例1至对比例3中卷芯进行穿钉测试，穿钉测试条件是在A位置和B位置(这两个位置可以参考图4和图5)使用3mm钢钉，以30mm/s的速度刺穿电池，判定标准：如果电池不冒烟、不起火则判定为通过，如果冒烟、起火则判定为不通过，测试结果如表1所示。
表1
对比例1采用的常规结构的卷芯在A位置测试50pcs，在16pcs时冒烟并起火，通过率为68％；在B位置测试50pcs，在0pcs时冒烟并起火，通过率为100％，可以看出常规结构的卷芯在A位置和B位置的穿钉测试通过率有明显差异，该常规结构的卷芯充放电电压范围为4.45V至3V，容量为5000mAh，能量密度为712Wh/L。而本公开的实施例中的卷芯在A位置测试50pcs，在0pcs时冒烟并起火，通过率为100％；在B位置测试50pcs，在0pcs时冒烟并起火，通过率为100％，可以看出A位置和B位置的穿钉测试通过率得到了明显的提升，本公开的实施例中的卷芯充放电电压范围为4.45V至3V，容量为5000mAh，能量密度为720Wh/L，与常规结构的卷芯(例如，锂离子电池)相比，能量密度提升了8Wh/L。
另外，由表1中也可以看出，在第一集流体110上设置底涂层140和绝缘保护层150，能够保证穿钉测试的性能，从而有利于提高卷芯的安全性。
虽然本公开披露如上，但本公开的保护范围并非仅限于此。本领域技术人员在不脱离本公开的精神和范围的前提下，可进行各种变更与修改，这些变更与修改均将落入本公开的保护范围。

Claims (20)

  1. 一种卷芯，其特征在于，包括层叠设置的第一极片和第二极片，所述第一极片从所述第一极片的首端向所述第一极片的尾端卷绕，所述第二极片从所述第二极片的首端向所述第二极片的尾端卷绕；
    所述第一极片的尾端为第一空箔区，所述第二极片的尾端为第二空箔区；
    所述卷芯包括设置于所述卷芯的最外侧的第一弯折区，所述第一极片的尾端和所述第二极片的尾端均位于所述第一弯折区，且所述第一空箔区和所述第二空箔区沿所述卷芯的厚度方向的投影均不超过所述第一弯折区。
  2. 根据权利要求1所述的卷芯，其特征在于，所述第一空箔区沿卷绕方向的尺寸范围为0.1mm至πT/2+8mm，其中，T为所述卷芯的厚度。
  3. 根据权利要求1或2所述的卷芯，其特征在于，所述第二空箔区沿卷绕方向的尺寸范围为0.1mm至10mm。
  4. 根据权利要求1至3中任一项所述的卷芯，其特征在于，所述第一极片包括第一集流体和第一活性物质层，在所述第一空箔区所在位置处，所述第一集流体的双侧表面均未涂敷所述第一活性物质层。
  5. 根据权利要求4所述的卷芯，其特征在于，所述第一极片还包括底涂层，所述底涂层位于所述第一集流体和所述第一活性物质层之间。
  6. 根据权利要求4或5所述的卷芯，其特征在于，位于所述卷芯的最外圈的第一极片上还设置有绝缘保护层，所述绝缘保护层设置在所述第一集流体背离所述第一活性物质层的一侧表面，且所述绝缘保护层延伸至所述第一空箔区的尾端。
  7. 根据权利要求1至6中任一项所述的卷芯，其特征在于，所述第一极片沿卷绕方向依次形成第三空箔区、第一极片双面涂敷区、第一极片单面涂敷区和所述第一空箔区。
  8. 根据权利要求7所述的卷芯，其特征在于，所述第二极片沿卷绕方向依次形成第四空箔区、第二极片单面涂敷区、第二极片双面涂敷区和所述第二空箔区。
  9. 根据权利要求8所述的卷芯，其特征在于，沿所述卷芯的厚度方向，所述第二极片双面涂敷区和所述第二空箔区的交接处的投影覆盖所述第一极片单面涂敷区和所述第一空箔区的交接处的投影。
  10. 根据权利要求8或9所述的卷芯，其特征在于，所述第二极片双面空箔区和所述第二空箔区的交接处距离第一端面的间距范围大于或等于T/2mm，且小于或等于T/2+8mm，其中，所述第一端面为所述卷芯的弯折区域最突出的点沿所述卷芯的厚度方向延伸形成的 面，T为所述卷芯的厚度。
  11. 根据权利要求8至10中任一项所述的卷芯，其特征在于，所述第一空箔区沿所述卷绕方向伸出所述第二空箔区。
  12. 根据权利要求8至11中任一项所述的卷芯，其特征在于，还包括第一极耳和第二极耳，所述第一极耳设置于所述第三空箔区，所述第二极耳设置于所述第四空箔区，沿所述卷芯的厚度方向，所述第一极耳和所述第二极耳的投影不重叠。
  13. 根据权利要求12所述的卷芯，其特征在于，还包括绝缘层，所述绝缘层包括第一绝缘层、第二绝缘层、第三绝缘层、第四绝缘层、第五绝缘层、第六绝缘层和第七绝缘层，所述第五绝缘层覆盖所述第一极耳的表面，所述第六绝缘层覆盖所述第二极耳的表面，所述第七绝缘层覆盖所述第二极片与所述第三空箔区的首端相对的位置，所述第四绝缘层覆盖所述第三空箔区和所述第一极片双面涂敷区的交接处，所述第三绝缘层覆盖所述第一极片双面涂敷区和所述第一极片单面涂敷区的交接处，所述第二绝缘层覆盖所述第一极片单面涂敷区和所述第一空箔区的交接处，所述第一绝缘层覆盖所述第一空箔区在朝向所述卷芯的外部的一侧表面以及绝缘保护层背离所述第一极片的第一集流体的一侧表面中的至少一个表面，所述绝缘保护层设置在所述卷芯的最外圈的第一极片上。
  14. 根据权利要求13所述的卷芯，其特征在于，所述第一绝缘层朝所述第一弯折区延伸，并且所述第一绝缘层沿所述卷芯的厚度方向的投影覆盖所述第一弯折区沿所述卷芯的厚度方向的投影。
  15. 根据权利要求1至14中任一项所述的卷芯，其特征在于，所述第一极片和所述第二极片的极性相反，所述第一极片为正极片，所述第二极片为负极片。
  16. 根据权利要求1至15中任一项所述的卷芯，其特征在于，所述第二极片包括第二集流体和第二活性物质层，在所述第二空箔区所在位置处，所述第二集流体的双侧表面均未涂敷所述第二活性物质层。
  17. 根据权利要求1至16中任一项所述的卷芯，其特征在于，还包括设置在所述第一极片和所述第二极片之间的隔膜，所述隔膜从所述隔膜的首端向所述隔膜的尾端卷绕。
  18. 根据权利要求17所述的卷芯，其特征在于，所述隔膜的尾端超出所述第二空箔区的尾端。
  19. 根据权利要求17或18所述的卷芯，其特征在于，卷绕完成的隔膜具有两个尾端，所述两个尾端包裹所述第二空箔区的尾端。
  20. 一种电池，其特征在于，包括壳体和如权利要求1至19中任一项所述的卷芯，所述卷芯封装于所述壳体内。
PCT/CN2023/098034 2022-08-23 2023-06-02 卷芯和电池 WO2024041080A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202222216587.2 2022-08-23
CN202222216587.2U CN218602515U (zh) 2022-08-23 2022-08-23 一种卷芯和电池

Publications (1)

Publication Number Publication Date
WO2024041080A1 true WO2024041080A1 (zh) 2024-02-29

Family

ID=85396553

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2023/098034 WO2024041080A1 (zh) 2022-08-23 2023-06-02 卷芯和电池

Country Status (2)

Country Link
CN (1) CN218602515U (zh)
WO (1) WO2024041080A1 (zh)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN218602515U (zh) * 2022-08-23 2023-03-10 珠海冠宇电池股份有限公司 一种卷芯和电池

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN208078114U (zh) * 2018-04-13 2018-11-09 宁德新能源科技有限公司 一种电池
US20210376372A1 (en) * 2020-06-02 2021-12-02 Contemporary Amperex Technology Co., Limited Electrode assembly and related battery, battery module
CN216850053U (zh) * 2022-02-24 2022-06-28 珠海冠宇电池股份有限公司 一种卷芯和电池
CN218602515U (zh) * 2022-08-23 2023-03-10 珠海冠宇电池股份有限公司 一种卷芯和电池

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN208078114U (zh) * 2018-04-13 2018-11-09 宁德新能源科技有限公司 一种电池
US20210376372A1 (en) * 2020-06-02 2021-12-02 Contemporary Amperex Technology Co., Limited Electrode assembly and related battery, battery module
CN216850053U (zh) * 2022-02-24 2022-06-28 珠海冠宇电池股份有限公司 一种卷芯和电池
CN218602515U (zh) * 2022-08-23 2023-03-10 珠海冠宇电池股份有限公司 一种卷芯和电池

Also Published As

Publication number Publication date
CN218602515U (zh) 2023-03-10

Similar Documents

Publication Publication Date Title
JP6296569B2 (ja) 正極タブ上に絶縁層を含む正極及びこれを含む二次電池
JP4075034B2 (ja) 非水電解質電池およびその製造方法
WO2022036721A1 (zh) 电极组件、电池单体、电池及制造电极组件的方法和装置
JP6863710B2 (ja) 二次電池
WO2023093503A1 (zh) 电极片及电化学装置
CN109473729A (zh) 电化学装置
WO2023284383A1 (zh) 电化学装置及电子装置
WO2022142256A1 (zh) 一种锂离子电池
CN214313300U (zh) 一种电极组件和二次电池
WO2022188864A1 (zh) 一种电极片及其应用
JP2010225545A (ja) リチウムイオン二次電池用電極及びリチウムイオン二次電池
WO2024041080A1 (zh) 卷芯和电池
WO2023201588A1 (zh) 电化学装置及用电设备
WO2022156459A1 (zh) 锂离子电池的负极片、锂离子电池和电子设备
JP4245205B2 (ja) 非水電解質電池
JP2001155779A (ja) 非水電解質電池
JP5150095B2 (ja) 非水電解質電池
WO2024087906A1 (zh) 一种电芯及电池
JP2011187241A (ja) 非水電解質二次電池
JP5674357B2 (ja) リチウムイオン二次電池
WO2023279298A1 (zh) 电化学装置及包括该电化学装置的电子装置
CN217507394U (zh) 一种极片、电芯和电池
JP2014013778A (ja) 非水電解質二次電池
JPH1167276A (ja) 非水電解液二次電池
CN115842091A (zh) 一种电池极片、电芯、电池、电池模块、电池包及用电装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23856172

Country of ref document: EP

Kind code of ref document: A1