WO2024259583A1 - 电化学装置及电子装置 - Google Patents

电化学装置及电子装置 Download PDF

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Publication number
WO2024259583A1
WO2024259583A1 PCT/CN2023/101367 CN2023101367W WO2024259583A1 WO 2024259583 A1 WO2024259583 A1 WO 2024259583A1 CN 2023101367 W CN2023101367 W CN 2023101367W WO 2024259583 A1 WO2024259583 A1 WO 2024259583A1
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WO
WIPO (PCT)
Prior art keywords
layer
electrochemical device
region
wall
electrode assembly
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/CN2023/101367
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English (en)
French (fr)
Inventor
江南
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ningde Amperex Technology Ltd
Original Assignee
Ningde Amperex Technology Ltd
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 Ningde Amperex Technology Ltd filed Critical Ningde Amperex Technology Ltd
Priority to CN202380033801.5A priority Critical patent/CN119096416B/zh
Priority to EP23941890.8A priority patent/EP4734268A1/en
Priority to PCT/CN2023/101367 priority patent/WO2024259583A1/zh
Publication of WO2024259583A1 publication Critical patent/WO2024259583A1/zh
Priority to US19/424,778 priority patent/US20260112793A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • H01M10/04—Construction or manufacture in general
    • H01M10/0431—Cells with wound or folded electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/109—Primary casings; Jackets or wrappings characterised by their shape or physical structure of button or coin shape
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
    • H01M50/121—Organic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/538—Connection of several leads or tabs of wound or folded electrode stacks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • 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 energy storage technology, and in particular to an electrochemical device and an electronic device having the electrochemical device.
  • Electrochemical devices such as secondary batteries
  • electronic products such as electronic mobile devices, power tools and electric vehicles, and people have increasingly higher requirements for the reliability and safety of electrochemical devices.
  • Electrochemical devices usually include a conductive plate, which connects the pole piece and the housing, thereby leading the electrode polarity of the pole piece through the housing.
  • a conductive plate which connects the pole piece and the housing, thereby leading the electrode polarity of the pole piece through the housing.
  • the burrs of the conductive plate may pierce the isolation membrane and cause a short circuit.
  • the conductive plate may also suffer fatigue fracture, which may lead to the failure of the electrochemical device and affect the safety, reliability and service life of the electrochemical device.
  • the present application provides an electrochemical device, comprising a housing and an electrode assembly.
  • the housing comprises a first wall and a side wall connected to the first wall.
  • the first wall and the side wall are arranged to form a receiving cavity, and the electrode assembly is received in the receiving cavity.
  • the direction from the first wall to the electrode assembly is the first direction.
  • the electrode assembly is a winding structure, and comprises a first pole piece, a second pole piece, and a separator disposed between the first pole piece and the second pole piece.
  • the electrochemical device also comprises a first conductive plate and a first layer.
  • the first conductive plate comprises a first conductive region and a second conductive region connected to each other, and the second conductive region is bent compared to the first conductive region.
  • the first conductive region is connected to the first pole piece, and the second conductive region is connected to the first wall.
  • the second conductive region comprises a first end connected to the first conductive region and a second end disposed opposite to the first end.
  • the second conductive region extends from the first end in a second direction perpendicular to the first direction.
  • the first layer comprises an insulating material. In the first direction, the first layer is disposed between the electrode assembly and the second conductive region. When viewed from the first direction, the first layer comprises a first side extending along an edge of the electrode assembly and a second side connected to the first side. The second side overlaps with the electrode assembly, and the second side is further away from the edge of the electrode assembly than the first side, so that the first layer forms a gap.
  • the second layer When viewed from the first direction, the second end overlaps with the first layer.
  • the second layer includes an insulating material.
  • the second layer includes a first area covering the second conductive area, and the first area includes a first partition and a second partition connected. When viewed from the first direction, the first partition covers the gap, and the second partition overlaps with the first layer.
  • the first layer is used to isolate the electrode assembly from the first wall, reducing the possibility of a short circuit caused by direct contact between the electrode assembly and the first wall.
  • the first layer can also cover the burrs of the second conductive area, reducing the possibility of the burrs piercing the isolation membrane and causing a short circuit.
  • the first layer can reduce the compression of the bend between the first conductive area and the second conductive area, thereby reducing the possibility of the first conductive plate breaking under stress and causing the electrochemical device to fail.
  • the invention also reduces the possibility of the sharp tip generated after the first conductive plate breaks piercing the isolation membrane and causing a short circuit. Therefore, the reliability and service life of the electrochemical device are improved. Furthermore, the present application sets the first area of the second layer to cover the gap, so the first area can cooperate with the first layer to isolate the electrode assembly and the first wall, reducing the possibility of a short circuit caused by the gap in the first layer. In addition, the second layer can also reduce the possibility of warping at the second edge and make it difficult for the first layer to move in the shell.
  • the first end when viewed from the first direction, is located in the notch, which can reduce the contact friction between the first end and the side wall.
  • the surface of the first layer facing the first wall includes a first recess, and the first layer is connected to the second conductive area at the first recess. In this way, the total thickness of the second conductive area and the first layer in the first direction can be reduced while ensuring the thickness of the first layer, which is conducive to improving the energy density.
  • the second side includes a curved portion. Considering that a notch may be formed on the second side when the first layer is cut, the possibility of the notch further expanding to form a crack during the installation of the first layer can be reduced by setting the second side to include a curved portion.
  • the third direction is defined to be perpendicular to the first direction and the second direction, the size of the second side in the third direction is d 2 , the size of the second conductive area in the third direction is d, and d 2 > d. Therefore, the first layer can fully cover the second conductive area, reducing the possibility of the burrs of the second conductive area piercing the isolation film and causing a short circuit. Moreover, the first layer can fully isolate the electrode assembly from the first wall, reducing the possibility of a short circuit caused by direct contact between the electrode assembly and the first wall.
  • the first electrode sheet includes a first current collector and a first active material layer disposed on a surface of the first current collector.
  • the first current collector includes a first portion separated from the first active material layer, and the first conductive region is connected to the first portion.
  • the first conductive region in the second direction, is disposed on the surface of the first portion facing the side wall. Due to the blocking of the first portion, the possibility of burrs of the first conductive region piercing the isolation film and causing a short circuit can be reduced.
  • the first region is disposed between the second conductive region and the electrode assembly in the first direction.
  • the first region cooperates with the first layer to isolate the electrode assembly and the first wall and to cover the burrs of the second conductive region, thereby reducing the possibility of short circuit.
  • the second layer further includes a second region connected to the first region.
  • the second region covers the first conductive region.
  • the second region is used to cover the burrs of the first conductive region, further reducing the possibility of the burrs piercing the isolation film and causing a short circuit.
  • the electrochemical device further includes a third layer comprising an insulating material.
  • the third layer includes a third region disposed between the second conductive region and the first wall in the first direction.
  • the third region includes a third partition and a fourth partition connected to each other. When viewed from the first direction, the third partition covers the gap, and the fourth partition overlaps the first layer.
  • the third region is used to cooperate with the first layer to isolate the electrode assembly and the first wall, thereby reducing the possibility of a short circuit.
  • the third layer further includes a fourth region connected to the third region.
  • the first conductive region is disposed between the second region and the fourth region.
  • the fourth region is used to cover burrs or weld marks of the first conductive region.
  • the second layer includes a laminated adhesive layer and a substrate.
  • the adhesive layer includes an insulating material.
  • the substrate is bonded to the first conductive plate through the adhesive layer. Since the third layer is not bonded to the electrode assembly, the electrolyte between the first layer and the first wall after injection can fully infiltrate the electrode assembly, improve the interface during the cycle, reduce the capacity attenuation caused by lithium precipitation, black spots, purple spots, etc., and improve the cycle performance of the electrochemical device.
  • the material of the substrate is selected from at least one of polyimide and polyethylene terephthalate.
  • the insulating material of the adhesive layer is selected from at least one of butadiene, isoprene, styrene, methyl methacrylate, butyl methacrylate, isooctyl acrylate, or butyl acrylate, so that the adhesive layer has better adhesion.
  • the fourth partition includes a second end away from the third partition in the second direction, the size of the second end and the side wall in the second direction is d 5 , the radius of the first wall is R, and d 5 ⁇ 0.4 R. In this way, the influence of the third area on the connection (welding) area between the second conductive plate and the first wall can be reduced, that is, the possibility of the third area interfering with the above connection area and causing failure of the connection area can be reduced.
  • the third direction is defined to be perpendicular to the first direction and the second direction, the size of the second side in the third direction is d 2 , the size of the first region in the third direction is d 3 , and d 2 ⁇ d 3 .
  • the first region and the first layer can be used to isolate the electrode assembly and the first wall, reducing the possibility of short circuit.
  • the distance between the second side and the side wall in the second direction is a first distance L
  • the second partition includes a first end away from the first partition in the second direction
  • the size of the first end and the side wall in the second direction is d 1 , 0.4d 1 ⁇ L ⁇ d 1 , thereby reducing the possibility that the electrolyte between the first layer and the first wall after injection is not easy to fully infiltrate the electrode assembly when the L value is too small, thereby improving the wetting effect of the electrode assembly, thereby improving the interface during the cycle process, reducing the capacity attenuation caused by lithium precipitation, black spots, purple spots, etc., and improving the cycle performance of the electrochemical device.
  • the second conductive area when viewed from the first direction, overlaps with the winding center axis of the electrode assembly, so the second conductive area has a larger size in the second direction, which is beneficial to improving the connection strength between the second conductive area and the first wall.
  • a cavity is provided at the winding start end of the electrode assembly.
  • the first layer covers the cavity.
  • the housing further includes a second wall connected to the side wall and disposed opposite to the first wall.
  • the second wall is provided with a conductive member electrically insulated from the second wall.
  • the electrode assembly further includes a second conductive plate electrically connected to the second pole piece, and the second conductive plate is connected to the conductive member. In this way, the first wall and the conductive member present opposite electrical polarities, so that the electrochemical device can supply power to external components.
  • the electrochemical device is a button battery, and the edge of the electrode assembly is substantially circular when viewed from the first direction. Since button batteries are generally small in size, in this implementation, it is not necessary to reduce the compression of the first layer on the bend of the first conductive plate by reducing the size of the electrode assembly, which is conducive to improving energy density.
  • the second aspect of the present application also provides an electronic device, which includes the electrochemical device as described above.
  • the electronic device is powered by the electrochemical device, and the electrochemical device reduces the possibility of the first conductive plate breaking by setting the second side farther away from the edge of the electrode assembly than the first side, thereby maintaining high reliability and service life.
  • FIG. 1A is a three-dimensional structural diagram of an electrochemical device according to an embodiment of the present application.
  • FIG. 1B is a top view of the electrochemical device shown in FIG. 1A when viewed from a first direction.
  • FIG. 2A is a cross-sectional view of the electrochemical device shown in FIG. 1A taken along line II-II.
  • FIG. 2B is a schematic structural diagram of the first electrode sheet of the electrochemical device shown in FIG. 2A before winding the electrode assembly when viewed from a fifth direction.
  • FIG. 2C is a schematic structural diagram of the first pole piece shown in FIG. 2B when viewed from a first direction.
  • FIG. 3 is a cross-sectional view of the electrochemical device shown in FIG. 1B along line III-III.
  • FIG. 4 is an enlarged view of the electrochemical device shown in FIG. 3 at point A.
  • FIG. 4 is an enlarged view of the electrochemical device shown in FIG. 3 at point A.
  • FIG5 is a cross-sectional view of the electrochemical device shown in FIG1B along line V-V.
  • FIG. 6 is a bottom view of the electrochemical device shown in FIG. 1A when the first wall of the shell is removed and the device is viewed along the first direction.
  • FIG. 7 is a bottom view of the electrochemical device shown in FIG. 6 when the third layer is removed and viewed along the first direction.
  • FIG. 8 is a cross-sectional view of the second layer of the electrochemical device shown in FIG. 7 .
  • FIG. 9 is a schematic structural diagram of an electrochemical device according to another embodiment of the present application.
  • FIG. 10 is a cross-sectional view of an electrochemical device according to yet another embodiment of the present application.
  • FIG. 11 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
  • Spatial related terms such as “on” and the like can be used herein for convenient description, to describe the relationship between an element or feature and another element (multiple elements) or feature (multiple features) as illustrated in the figure. It should be understood that, in addition to the directions described in the figure, spatial related terms are intended to include different directions of equipment or devices in use or operation. For example, if the equipment in the figure is turned over, the elements described as “above” or “on” other elements or features will be oriented “below” or “below” other elements or features. Therefore, the exemplary term “on” may include the direction above and below. It should be understood that although the terms first, second, third, etc.
  • parallel and “perpendicular” are used to describe the ideal state between two components. In actual production or use, there may be a state that is approximately parallel or perpendicular between two components.
  • parallel can refer to the angle range between two straight lines being between ⁇ 10°
  • parallel can also refer to the dihedral angle range between two planes being between ⁇ 10°
  • parallel can also refer to the angle range between a straight line and a plane being between ⁇ 10°.
  • Perpendicular can refer to the angle range between two straight lines being between 90 ⁇ 10°, perpendicular can also refer to the dihedral angle range between two planes being between 90 ⁇ 10°, and perpendicular can also refer to the angle range between a straight line and a plane being between 90 ⁇ 10°.
  • the two components described as “parallel” and “perpendicular” may not be absolute straight lines or planes, but may be roughly straight lines or planes. From a macroscopic point of view, the components can be considered “straight lines” or "planes” if the overall extension direction is a straight line or a plane.
  • the parameter values being greater than, less than, or not equal to the designed relationship need to exclude the reasonable errors of the measuring equipment.
  • an embodiment of the present application provides an electrochemical device 100, including a housing 10, an electrode assembly 20 and an electrolyte (not shown).
  • the housing 10 includes a first wall 11, a second wall 12 and a side wall 13.
  • the first wall 11 and the second wall 12 are arranged opposite to each other in a first direction X.
  • the first wall 11 may be roughly circular, and the second wall 12 may also be roughly circular.
  • the first wall 11 and the second wall 12 may be arranged in parallel and both are perpendicular to the first direction X.
  • the first edge 131 of the side wall 13 is connected to the first wall 11, and the second edge 132 of the side wall 13 is connected to the second wall 12, so that a roughly cylindrical accommodating chamber S1 is formed in the housing 10.
  • the first wall 11 covers the accommodating chamber S1.
  • the electrode assembly 20 and the electrolyte are accommodated in the accommodating chamber S1, and the first direction X is also the direction from the first wall 11 to the electrode assembly 20.
  • the electrochemical device 100 is a button battery.
  • the side wall 13 and the second wall 12 can be integrally formed, and the second wall 12 and the side wall 13 can be welded or clamped.
  • the shell 10 can be made of steel as a whole.
  • the steel shell 10 includes elements Fe and C, and the steel shell can also include one or more of the elements Ni, Co, Al, Mn, Cr, Cu, Mg, Mo, S, Si, Ti, V, Pb, Sb, N, and P.
  • the first wall 11 is made of steel
  • the second wall 12 and the second wall 12 are also made of steel.
  • a conductive member 14 electrically insulated from the second wall 12 may be further provided on the second wall 12.
  • the second wall 12 is provided with a first opening 120 communicating with the accommodating cavity S1, and the conductive member 14 may be installed in the first opening 120 by bonding or riveting.
  • the conductive member 14 may include a conductive portion 141 and a mounting portion 142 connected to each other.
  • the conductive portion 141 is provided in the first opening 120
  • the mounting portion 142 is provided on the surface of the second wall 12 away from the first wall 11.
  • a first insulating layer 15 may be provided between the conductive member 14 and the second wall 12, and the first insulating layer 15 is used to electrically insulate the conductive member 14 from the second wall 12.
  • the first insulating layer 15 may be fixed between the conductive member 14 and the second wall 12 by interference fit. In other embodiments, the first insulating layer 15 may also be fixed between the conductive member 14 and the second wall 12 by riveting.
  • the material of the first insulating layer 15 may be polyethylene, polypropylene, propylene-ethylene copolymer, polyetheretherketone, polyvinylidene fluoride or polytetrafluoroethylene.
  • the conductive portion 141 may be provided with a second opening 1410, and the second opening 1410 is located inside the first opening 120 when viewed from the first direction X.
  • the electrolyte may flow into the accommodation chamber S1 through the second opening 1410.
  • a sealing member 143 may be installed on the conductive portion 141, and the sealing member 143 covers the second opening 1410.
  • the electrode assembly 20 is a winding structure and has a winding center axis O.
  • the first direction X is also the direction of the winding center axis O of the electrode assembly 20.
  • the electrode assembly 20 includes a first electrode sheet 21, a second electrode sheet 22, and a second electrode sheet 23.
  • the pole piece 22 and the isolation film 23 provided between the first pole piece 21 and the second pole piece 22.
  • the isolation film 23 is used to prevent the first pole piece 21 and the second pole piece 22 from directly contacting each other, thereby reducing the possibility of contact short circuit between the first pole piece 21 and the second pole piece 22.
  • the isolation film 23 is shown as a dotted line (composed of multiple short lines at intervals).
  • the edge of the electrode assembly 20 can also be roughly circular when viewed from the first direction X.
  • the isolation film 23 is located at least part of the outermost layer of the electrode assembly 20.
  • the isolation film 23 is located at the outermost layer of the electrode assembly 20.
  • the isolation film 23 can form a protective layer to reduce the risk of short circuit caused by wear of the pole piece inside the portion of the isolation film 23, thereby increasing the ability of the electrode assembly 20 to resist mechanical impact.
  • the first pole piece 21 or the second pole piece 22 can also be located at the outermost layer of the electrode assembly 20.
  • the winding start end 2001 of the electrode assembly 20 may be provided with a cavity S2.
  • the winding center axis O passes through the cavity S2 along the first direction X.
  • the first pole piece 21, the isolation film 23, and the second pole piece 22 may be wound by a winding needle (not shown), and the winding needle is extracted after the electrode assembly 20 is formed, thereby forming the above-mentioned cavity S2 in the electrode assembly 20.
  • the innermost circle of the isolation film 23 is the winding start end 2001 of the electrode assembly 20.
  • the first pole piece 21 when the first pole piece 21 is unfolded, another three-dimensional coordinate system is established according to the mutually perpendicular first direction X, fourth direction Y' and fifth direction Z', and the fourth direction Y' is defined as the extension direction of the first pole piece 21 before winding, and the fifth direction Z' is the thickness direction of the first pole piece 21 after unfolding.
  • the first pole piece 21 includes a first active material layer 211, a first current collector 210 and a second active material layer 212 stacked in sequence.
  • the fifth direction Z' is the stacking direction of the first current collector 210 and the first active material layer 211 after unfolding.
  • the first current collector 210 includes a first surface 2101 and a second surface 2102 arranged oppositely, the first surface 2101 is farther away from the winding center axis O than the second surface 2102, the first active material layer 211 is arranged on the first surface 2101, and the second active material layer 212 is arranged on the second surface 2102.
  • the first current collector 210 may include aluminum or nickel.
  • the first current collector 210 includes copper.
  • the first active material layer 211 and the second active material layer 212 both include active materials, which can be selected from at least one of graphite materials, alloy materials, lithium metal and alloys thereof.
  • the graphite material can be selected from at least one of artificial graphite and natural graphite; the alloy material can be selected from at least one of silicon, silicon oxide, tin and titanium sulfide.
  • the second pole piece 22 includes a third active material layer 221, a second current collector 220 and a fourth active material layer 222 stacked.
  • the second current collector 220 includes a third surface 2201 and a fourth surface 2202 arranged opposite to each other, the third surface 2201 is closer to the winding center axis O than the fourth surface 2202, the third active material layer 221 is arranged on the third surface 2201, and the fourth active material layer 222 is arranged on the fourth surface 2202.
  • the second current collector 220 may include copper, nickel or a carbon-based conductor.
  • the second current collector 220 when the second pole piece 22 is a positive electrode, the second current collector 220 includes aluminum foil, which has a weak strength but good conductivity.
  • the third active material layer 221 and the fourth active material layer 222 both include active materials, such as lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, nickel cobalt manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium phosphate, lithium rich manganese-based material or lithium nickel cobalt aluminum oxide.
  • active materials such as lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, nickel cobalt manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium phosphate, lithium rich manganese-based material or lithium nickel cobalt aluminum oxide.
  • the isolation film 23 includes at least one of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide or aramid.
  • the electrochemical device 100 further includes a first conductive plate 30.
  • FIG3 is a cross-sectional view of the electrochemical device shown in FIG1B along line III-III
  • FIG4 is an enlarged view of the electrochemical device shown in FIG3 at point A.
  • FIG. 1A and FIG. 1B when a cross section of the electrochemical device 100 is made along III-III, the cross section passes through the first conductive plate 30, that is, the cross section shown in FIG. 3 and FIG. 4 includes the first conductive plate 30.
  • the first conductive plate 30 includes a first conductive region 31 and a second conductive region 32 connected to each other. The second conductive region 32 is bent compared to the first conductive region 31.
  • the first conductive region 31 is connected to the first electrode sheet 21 (e.g., the first current collector 210 connected to the first electrode sheet 21), and the first conductive region 31 can extend out of the first electrode sheet 21 along the first direction X.
  • the second conductive region 32 is connected to the first wall 11. In the first direction X, the second conductive region 32 is disposed between the first wall 11 and the electrode assembly 20. Among them, the second conductive region 32 includes a first end 321 connected to the first conductive region 31 and a second end 322 away from the first end 321, and the second conductive region 32 extends from the first end 321 along the second direction Y.
  • the second direction Y is the direction from the first end 321 to the second end 322.
  • the first conductive plate 30 When viewed from a third direction Z perpendicular to the first direction X and the second direction Y, the first conductive plate 30 is bent at the first end 321, and the first conductive area 31 may be substantially perpendicular to the second conductive area 32. When viewed from the first direction X, the bend between the first conductive area 31 and the second conductive area 32 overlaps with the electrode assembly 20. As shown in FIG4 , the first conductive plate 30 includes a first surface 301 facing the housing 10 and a second surface 302 facing the electrode assembly 20. Since the first conductive plate 30 is bent, the first surface 301 and the second surface 302 are not planes, and the first surface 301 and the second surface 302 are respectively bent surfaces.
  • the first current collector 210 includes a first portion 2100, a first surface 2101 of the first portion 2100 is separated from the first active material layer 211, and a first conductive region 31 is connected to the first surface 2101 of the first portion 2100.
  • the first conductive region 31 may be provided on the surface of the first portion 2100 facing the side wall 13 (i.e., the first surface 2101 of the first portion 2100).
  • the first conductive area 31 By setting the first conductive area 31 on the surface of the first part 2100 facing the side wall 13, due to the obstruction of the first part 2100, the possibility of burrs of the first conductive area 31 (e.g., burrs may be formed during the cutting process of the first conductive plate 30, but this application is not limited thereto) piercing the isolation film 23 and causing the first pole piece 21 and the second pole piece 22 to directly contact and cause a short circuit can be reduced.
  • the second surface 2102 of the first part 2100 can also be separated from the second active material layer 212, and the first part 2100 can be the tail empty foil area of the first pole piece 21 at this time.
  • the first conductive area 31 can be welded to the first surface 2101 of the first part 2100, and the second conductive area 32 can be welded to the first wall 11.
  • the second conductive region 32 overlaps with the winding center axis O of the electrode assembly 20 when viewed from the first direction X. Since the second conductive region 32 extends to overlap with the winding center axis O, the second conductive region 32 has a larger size in the second direction Y, which is beneficial to improve the connection strength between the second conductive region 32 and the first wall 11.
  • the electrochemical device 100 also includes a second conductive plate 40.
  • Figure 5 is a cross-sectional view of the electrochemical device shown in Figure 1B along VV. In combination with Figure 1A and Figure 1B, it can be seen that when a cross section of the electrochemical device 100 is made along VV, the cross section passes through the second conductive plate 40, that is, the cross section shown in Figure 5 includes the second conductive plate 40.
  • the second conductive plate 40 includes a third conductive region 41 and a fourth conductive region 42 connected to each other.
  • the third conductive region 41 is connected to the second pole piece 22 (such as the second current collector 220 connected to the second pole piece 22), and the third conductive region 41 can extend out of the second pole piece 22 along the first direction X.
  • the fourth conductive region 42 is connected to the conductive member 14 (such as the conductive portion 141 connected to the conductive member 14). In the first direction X, the fourth conductive region 42 is arranged between the second wall 12 and the electrode assembly 20. Among them, the fourth conductive region 42 includes a third conductive region 41 connected to the third conductive region. The fourth conductive region 41 includes a third end 421 and a fourth end 422 away from the third end 421 . The fourth conductive region 42 extends along the second direction Y from the third end 421 .
  • the second current collector 220 includes a second portion 2200, a third surface 2201 of the second portion 2200 is separated from the third active material layer 221, and a third conductive region 41 is connected to the third surface 2201 of the second portion 2200.
  • the fourth surface 2202 of the second portion 2200 may also be separated from the fourth active material layer 222, and the second portion 2200 may be the tail empty foil region of the second electrode sheet 22 at this time.
  • the third conductive region 41 may be welded to the third surface 2201 of the second portion 2200, and the fourth conductive region 42 may be welded to the conductive member 14.
  • the first wall 11 and the conductive member 14 present opposite electrical polarities, so that the electrochemical device 100 can supply power to an external element (not shown).
  • the first electrode 21 is a negative electrode and the second electrode 22 is a positive electrode
  • the first wall 11, the side wall 13 and the second wall 12 are negative polarities as a whole
  • the conductive member 14 is positive polarity.
  • the electrochemical device 100 also includes a first layer 50 comprising an insulating material.
  • the first layer 50 is disposed between the electrode assembly 20 and the second conductive area 32.
  • the first layer 50 is used to isolate the electrode assembly 20 from the first wall 11, reducing the possibility of a short circuit caused by direct contact between the second pole piece 22 and the first wall 11.
  • the first layer 50 can also cover the burrs of the second conductive area 32 (e.g., the burrs can be formed during the cutting process of the first conductive plate 30, but this application is not limited thereto), reducing the possibility of the above-mentioned burrs piercing the isolation membrane 23, causing the first pole piece 21 and the second pole piece 22 to directly contact and cause a short circuit.
  • the insulating material of the first layer 50 can be selected from at least one of polypropylene, polyethylene, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate or polyethylene glycol.
  • the first layer 50 includes a fifth surface 501 facing the first wall 11 and a sixth surface 502 facing the electrode assembly 20.
  • the fifth surface 501 and the sixth surface 502 are arranged opposite to each other.
  • the fifth surface 501 of the first layer 50 includes a first recess 503, and the first recess 503 does not penetrate the sixth surface 502 along the first direction X.
  • At least part of the second conductive region 32 is disposed in the first recess 503, and the second surface 302 of the second conductive region 32 is connected to the bottom surface of the first recess 503.
  • the second surface 302 of the second conductive region 32 is located between the fifth surface 501 and the sixth surface 502 of the first layer 50.
  • the first surface 301 of the second conductive region 32 may be further away from the electrode assembly 20 than the fifth surface 501 of the first layer 50.
  • part of the second conductive region 32 including the second end 322 may be disposed in the first recess 503.
  • the first layer 50 is connected to the second conductive area 32 at the first recess 503. In this way, under the premise of ensuring the thickness of the first layer 50, the total thickness of the second conductive area 32 and the first layer 50 in the first direction X can be reduced, which is beneficial to improve the energy density.
  • the edge of the first recess 503 may overlap with the edge of the second conductive area 32.
  • the influence of the oversized size of the first recess 503 on the isolation effect of the first layer 50 is also reduced, so that the first layer 50 can fully isolate the electrode assembly 20 and the first wall 11 after the first recess 503 is opened.
  • the first layer 50 When viewed from the first direction X, the first layer 50 includes a first edge 51 that bends and extends along the edge of the electrode assembly 20 and a second edge 52 that is connected to the first edge 51.
  • FIG. 6 and FIG. 7 show the outermost layer of the electrode assembly 20, namely the separator 23, which is the edge of the electrode assembly 20 when viewed from the first direction X.
  • the edge of the electrode assembly 20 when viewed from the first direction X can be divided into a first segment 20a and a second segment 20b that are connected (when viewed from the first direction X, the edge of the electrode assembly 20 and the second edge 52 are compared with the first intersection P1 and the second intersection P2, and the first intersection P1 and the second intersection P2 divide the edge of the electrode assembly 20 into a first segment 20a and a second segment 20b), the first edge 51 is arranged opposite to the first segment 20a, and the second edge 52 is arranged opposite to the second segment 20b.
  • the first edge 51 bends and extends along the edge of the electrode assembly 20, which means that the extension direction of the first edge 51 is consistent or substantially consistent with the extension direction of the first segment 20a.
  • the edge of the electrode assembly 20 is roughly circular when observed from the first direction X
  • the first section 20a is an arc segment, that is, a part of a curved circumference, and the first edge 51 can also be set as an arc segment accordingly.
  • the edge shape of the electrode assembly 20 changes, the shape of the first edge 51 can also be different.
  • the first edge 51 in order to make the first layer 50 fully isolate the second electrode plate 22 from the first wall 11, when observed from the first direction X, the first edge 51 can be located outside the electrode assembly 20, at this time, the radius of the circumference defined by the first edge 51 is greater than the radius of the circumference defined by the first section 20a, and the distance between the first edge 51 and the first section 20a can be kept consistent or substantially consistent along the extension direction of the first edge 51. In other embodiments, when observed from the first direction X, the first edge 51 can also roughly overlap with the first section 20a.
  • the second side 52 When viewed from the first direction X, the second side 52 overlaps with the electrode assembly 20, and the second side 52 is further away from the edge of the electrode assembly 20 than the first side 51. Therefore, the second side 52 deviates from the circumference defined by the first side 51, and the second side 52 is located inside the circumference defined by the first side 51.
  • the second side 52 can be a straight line or include a curved portion. In some embodiments, the second side 52 is a straight line and extends along the third direction Z.
  • the second conductive region 32 When viewed from the first direction X, the second conductive region 32 extends from the first end 321 along the second direction Y to beyond the second side 52. Among them, since the second side 52 is further away from the edge of the electrode assembly 20 than the first side 51, the second side 52 deviates from the circumference defined by the first side 51, so the first layer 50 has a gap C when viewed from the first direction X, and the second side 52 is the edge of the gap C. When viewed from the first direction X, the first end portion 321 of the second conductive region 32 may be located within the notch C, thereby reducing the possibility of contact and friction between the first end portion 321 and the side wall 13 .
  • the size of the second side 52 in the third direction Z is d2
  • the size of the second conductive area 32 in the third direction Z is d, then d2 >d. Therefore, the first layer 50 can fully cover the second conductive area 32, reducing the possibility that the burrs of the second conductive area 32 pierce the isolation film 23 and cause the first pole piece 21 and the second pole piece 22 to directly contact and short-circuit.
  • the first layer 50 can fully isolate the second pole piece 22 and the first wall 11, reducing the possibility that the second pole piece 22 and the first wall 11 directly contact and short-circuit.
  • the steps for measuring d and d2 may be: (1) performing two-dimensional projection and scanning test on the electrochemical device 100 from a first direction X using X-rays, and the instrument may be an instrument or device known to those skilled in the art (e.g., GE Phoenix vtomex S device), so as to obtain a CT image; (2) directly measuring the values of d and d2 using a caliper or other suitable measuring tool.
  • the instrument may be an instrument or device known to those skilled in the art (e.g., GE Phoenix vtomex S device), so as to obtain a CT image; (2) directly measuring the values of d and d2 using a caliper or other suitable measuring tool.
  • the steps of measuring d and d2 may also be: (1) discharging the electrochemical device 100 at 0.2C to 2.75V; (2) cutting the side wall 13 of the housing 10 along a cross section perpendicular to the first direction X at a position close to the first edge 131, when most of the side wall 13 After being separated from the first wall 11, the first wall 11 is opened relative to the first layer 50, and the second conductive area 32 is still connected to the first wall 11; (3) using a caliper or other suitable measuring tool to directly measure the values of d and d2 .
  • the measurement steps of d and d2 can also be: (1) discharging the electrochemical device 100 at 0.2C to 2.75V; (2) preparing a resin composition, which is prepared by mixing a crystal glue resin matrix (such as epoxy resin), a catalyst and a curing agent in a certain proportion; (3) pouring the resin composition into a mold, placing the electrochemical device 100 in the mold, and then slowly pouring the resin composition so that the electrochemical device 100 is completely immersed in the resin composition; (4) taking out the electrochemical device 100 and then standing it until the resin composition solidifies; (5) grinding the first wall 11 of the shell 10 until the second conductive area 32 is exposed on the grinding surface; (6) using a caliper or other suitable measuring tool to directly measure the values of d and d2 .
  • the electrochemical device 100 further includes a second layer 60 comprising an insulating material.
  • the second layer 60 covers the first conductive plate 30.
  • the second layer 60 covers the notch C, thereby further reducing the possibility of a short circuit that may be caused by the first layer 50 being provided with the notch C.
  • the second layer 60 includes a first region 61 covering the second conductive region 32.
  • the first region 61 covers the notch C.
  • the second layer 60 covers the second surface 302 of the first conductive plate 30, and the first region 61 is disposed between the second conductive region 32 and the electrode assembly 20 in the first direction X.
  • the first region 61 is used to further isolate the electrode assembly 20 from the first wall 11, thereby reducing the possibility of a short circuit caused by direct contact between the second pole piece 22 and the first wall 11.
  • the second layer 60 can also cover the burrs of the second conductive region 32, thereby reducing the possibility of the above-mentioned burrs piercing the isolation film 23, causing the first pole piece 21 and the second pole piece 22 to directly contact and cause a short circuit.
  • the first region 61 of the second layer 60 is used to cooperate with the first layer 50 to isolate the electrode assembly 20 and the first wall 11 and to cover the burrs of the second conductive area 32, thereby reducing the possibility of a short circuit.
  • the first region 61 includes a first partition 611 and a second partition 612 connected to each other. Observed from the first direction X, the first partition 611 is located between the second conductive area 32 and the electrode assembly 20, and the first partition 611 overlaps with the notch C. Observed from the first direction X, the second partition 612 overlaps with the first layer 50. By setting the second partition 612 to overlap with the first layer 50, the first region 61 can fully cover the notch C.
  • the second partition 612 can also be arranged in the first recess 503.
  • the insulating material of the second layer 60 can be selected from at least one of polypropylene, polyethylene, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate or polyethylene glycol.
  • the second layer 60 can be a single-sided adhesive or a double-sided adhesive containing an insulating material.
  • the second layer 60 can also be a ceramic coating.
  • the distance between the second side 52 and the side wall 13 in the second direction Y is a first distance L
  • the second partition 612 has a first end 6120 away from the first partition 611 in the second direction Y
  • the dimension between the first end 6120 and the side wall 13 in the second direction Y is d 1 , L ⁇ d 1 .
  • L is the distance between the second side 52 and the part of the side wall 13 located on the side of the notch C away from the second side 52 in the second direction Y
  • d 1 is the distance between the first end 6120 and the part of the side wall 13 located on the side of the notch C away from the second side 52 in the second direction Y.
  • L and d 1 can be measured using similar measurement steps as d and d 2 .
  • the size of the second side 52 in the third direction Z is d 2
  • the size of the first region 61 in the third direction Z is d 3 , where d 2 ⁇ d 3 .
  • the first region 61 can fully cover the gap C in the third direction Z, so that the first region 61 is used to cooperate with the first layer 50 to isolate the electrode assembly 20 and the first wall 11 and to cover the burrs of the second conductive region 32 , thereby reducing the possibility of short circuit.
  • the second layer 60 may further include a second region 62 connected to the first region 61.
  • the second region 62 is used to cover the burrs of the first conductive region 31, further reducing the possibility that the burrs pierce the isolation film 23 and cause the first pole piece 21 and the second pole piece 22 to directly contact and cause a short circuit.
  • FIG. 7 only shows the first region 61 of the second layer 60, and does not show the second region 62 of the second layer 60.
  • the present application sets the second side 52 to be farther away from the edge of the electrode assembly 20 than the first side 51, so that the second side 52 can avoid the bend between the first conductive area 31 and the second conductive area 32.
  • the interference and compression of the first layer 50 on the bend between the first conductive area 31 and the second conductive area 32 can be reduced, thereby reducing the possibility of the first conductive plate 30 being broken under stress and causing the electrochemical device 100 to fail, and also reducing the possibility that the sharp tip generated after the first conductive plate 30 is broken pierces the isolation membrane 23, causing the first pole piece 21 and the second pole piece 22 to directly contact and cause a short circuit. Therefore, the reliability and service life of the electrochemical device 100 are improved.
  • this embodiment does not need to reduce the compression of the first layer 50 on the bending portion of the first conductive plate 30 by reducing the size of the electrode assembly 20 (for example, by reducing the size of the electrode assembly 20 and correspondingly increasing the gap between the electrode assembly 20 and the shell 10, a larger buffer space can be provided for the electrode assembly 20 in the event of mechanical abuse, thereby reducing the compression of the first layer 50 on the bending portion of the first conductive plate 30), which is beneficial to improving energy density.
  • the present application sets the first region 61 of the second layer 60 to cover the notch C, so the first region 61 can cooperate with the first layer 50 to isolate the electrode assembly 20 and the first wall 11, reducing the possibility of a short circuit caused by the notch C in the first layer 50.
  • the second layer 60 can also reduce the possibility of warping at the second edge 52, and make it difficult for the first layer 50 to move in the shell 10.
  • the second layer 60 is a single-sided adhesive bonded to the first conductive plate 30.
  • the second layer 60 includes a laminated adhesive layer 601 and a substrate 602.
  • the adhesive layer 601 contains an insulating material.
  • the substrate 602 is bonded to the first conductive plate 30 through the adhesive layer 601.
  • the electrolyte located between the first layer 50 and the first wall 11 after injection can flow through the gap C and fully infiltrate the electrode assembly 20, thereby improving the interface during the cycle process, reducing the capacity attenuation caused by lithium precipitation, black spots, purple spots, etc., and improving the cycle performance of the electrochemical device 100.
  • 0.4d 1 ⁇ L ⁇ d 1 can be set, thereby reducing the possibility that the size of the gap C is small when the L value is too small, and the electrolyte located between the first layer 50 and the first wall 11 after injection is not easy to flow through the gap C and fully infiltrate the electrode assembly 20, thereby improving the infiltration effect of the electrode assembly 20, thereby improving the interface during the cycle and reducing the capacity attenuation caused by lithium precipitation, black spots, purple spots, etc.
  • the material of the substrate 602 is selected from at least one of polyimide and polyethylene terephthalate.
  • the insulating material of the adhesive layer 601 can be selected from at least one of butadiene, isoprene, styrene, methyl methacrylate, butyl methacrylate, isooctyl acrylate or butyl acrylate.
  • the second layer 60 is set as a single-sided adhesive bonded to the first conductive plate 30 and the relationship between d1 and L can be further reasonably set, the electrolyte located between the first layer 50 and the first wall 11 after injection can flow through the gap C and fully infiltrate the electrode assembly 20. Therefore, in some embodiments, it can be set that the first layer 50 covers the cavity S2 of the electrode assembly 20 when viewed from the first direction X. That is, in order to fully infiltrate the electrode assembly 20, the present application does not need to cover the cavity S2 of the first layer 50 in the first layer 50. An opening should be provided at the location of the cavity S2 , thereby reducing the possibility that the welding marks or welding slag of the first conductive region 31 contact the second pole piece 22 through the opening and affect the life of the electrochemical device 100 .
  • the electrochemical device 100 further includes a third layer 70 comprising an insulating material.
  • the third layer 70 covers the first surface 301 of the first conductive plate 30. When viewed from the first direction X, the third layer 70 covers at least part of the notch C, thereby further reducing the possibility of a short circuit that may be caused by the first layer 50 after the notch C is set.
  • the third layer 70 includes a third region 71 disposed between the second conductive area 32 and the first wall 11 in the first direction X. When viewed from the first direction X, the third region 71 covers at least part of the notch C.
  • the third region 71 is used to further isolate the electrode assembly 20 and the first wall 11, thereby reducing the possibility of a short circuit caused by direct contact between the second electrode sheet 22 and the first wall 11. That is, the third region 71 of the third layer 70 is used to cooperate with the first layer 50 to isolate the electrode assembly 20 and the first wall 11, thereby reducing the possibility of a short circuit.
  • the third region 71 includes a third partition 711 and a fourth partition 712 connected to each other. When viewed from the first direction X, the third partition 711 overlaps with the notch C. When viewed from the first direction X, the fourth partition 712 overlaps the first layer 50.
  • the insulating material of the third layer 70 can be selected from at least one of polypropylene, polyethylene, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate or polyethylene glycol.
  • the fourth partition 712 has a second end 7120 away from the third partition 711 in the second direction Y, and the dimension between the second end 7120 and the side wall 13 in the second direction Y is d 5 , L ⁇ d 5 .
  • d 5 may be substantially equal to d 1 . It can be understood that d 5 is the distance between the second end 7120 and the portion of the side wall 13 located on the side of the notch C away from the second edge 52 in the second direction Y.
  • the radius of the first wall 11 is R (it can be understood that the radius R of the side wall 13 shown in FIG. 6 is the radius of the first wall 11), and d 5 ⁇ 0.4R.
  • R the radius of the side wall 13 shown in FIG. 6
  • d 5 the radius of the first wall 11
  • the influence of the third region 71 on the connection region (such as the welding region) between the second conductive plate 40 and the first wall 11 can be reduced, that is, the possibility of the third region 71 interfering with the above connection region and causing the connection region to fail can be reduced.
  • the size of the second side 52 in the third direction Z is d 2
  • the size of the third region 71 in the third direction Z is d 4 , where d 2 ⁇ d 4 .
  • the third region 71 can fully cover the gap C in the third direction Z, so that the third region 71 is used to cooperate with the first layer 50 to isolate the electrode assembly 20 and the first wall 11 , reducing the possibility of short circuit.
  • d 4 can be substantially equal to d 3 .
  • the third layer 70 may also include a fourth region 72 connected to the third region 71. As shown in FIG. 4, in the second direction Y, the fourth region 72 is located on the first surface 301 of the first conductive region 31. The fourth region 72 is used to cover the burrs or welding marks of the first conductive region 31.
  • the third layer 70 may be a single-sided adhesive or a double-sided adhesive containing an insulating material. In other embodiments, the third layer 70 may also be a ceramic coating. It can be understood that, for simplicity, FIG. 6 only shows the third region 71 of the third layer 70, and does not show the fourth region 72 of the third layer 70.
  • the electrochemical device 100 may further include a fourth layer 80 comprising an insulating material.
  • the fourth layer 80 is disposed between the electrode assembly 20 and the side wall 13.
  • the fourth layer 80 may reduce the possibility of a short circuit caused by direct contact between the second electrode piece 22 and the side wall 13 (e.g., the burrs of the second electrode piece 22 pierce the outermost isolation film 23 and contact the side wall 13).
  • the fourth layer 80 may be a continuous annular structure.
  • the insulating material of the fourth layer 80 can be selected from at least one of polypropylene, polyethylene, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, or polyethylene glycol.
  • another embodiment of the present application further provides an electrochemical device 200, which is different from the electrochemical device 100 in that the second side 52 includes a curved portion.
  • the second side 52 includes a curved portion.
  • another embodiment of the present application further provides an electrochemical device 300, which is different from the above electrochemical device 100 in that the first wall 11 is electrically isolated from the second wall 12.
  • the side wall 13 and the second wall 12 may be integrally formed, and the second wall 12 and the side wall 13 may be bonded and fixed by a second insulating layer 16, and the second insulating layer 16 electrically isolates the first wall 11 from the side wall 13, and the first wall 11 and the second wall 12 are also electrically isolated.
  • the fourth conductive area 42 of the second conductive plate 40 is connected to the second wall 12.
  • the first wall 11 and the second wall 12 have opposite electrical polarities, so that the electrochemical device 300 can supply power to external components.
  • the first electrode 21 is a negative electrode and the second electrode 22 is a positive electrode
  • the first wall 11 and the side wall 13 are negative polarities
  • the second wall 12 is positive polarity.
  • the electrochemical devices 100, 200, 300 of the present application include all devices capable of electrochemical reactions.
  • the electrochemical devices 100, 200, 300 include all kinds of primary batteries, secondary batteries, fuel cells, solar cells and capacitors (such as supercapacitors).
  • the electrochemical devices 100, 200, 300 can be lithium secondary batteries, including lithium metal secondary batteries, lithium ion secondary batteries, lithium polymer secondary batteries and lithium ion polymer secondary batteries.
  • an embodiment of the present application further provides an electronic device 1, comprising the electrochemical device 100 (or electrochemical device 200 , 300 ) described above.
  • the electronic device 1 is powered by the electrochemical device 100 , and the electrochemical device 100 reduces the possibility of the first conductive plate 30 breaking by setting the second side 52 farther away from the edge of the electrode assembly 20 than the first side 51 , thereby maintaining a high reliability and service life.
  • the electronic device 1 of the present application can be, but is not limited to, a notebook computer, a pen-input computer, a mobile computer, an e-book player, a portable phone, a portable fax machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, an LCD TV, a portable cleaner, a portable CD player, a mini disc, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, a car, a motorcycle, a power-assisted bicycle, a bicycle, a lighting fixture, a toy, a game console, a clock, an electric tool, a flashlight, a camera, a large household battery, and a lithium-ion capacitor, etc.
  • the performance of the electrochemical device 100 provided in the present application is described below through specific embodiments and comparative examples.
  • the present application is described by taking the electrochemical device 100 as a button-type lithium-ion battery as an example and combining the specific preparation process and testing method.
  • the preparation method described in the present application is only an example, and any other suitable preparation method is within the scope of the present application.
  • Preparation of the first electrode sheet 21 Mix the negative electrode active materials artificial graphite, conductive carbon black (Super P), and styrene-butadiene rubber (SBR) in a weight ratio of 96:1.5:2.5, add deionized water as a solvent, prepare a slurry with a weight percentage of 70wt%, and stir evenly. The slurry is evenly coated on one surface of a negative electrode current collector copper foil with a thickness of 10 ⁇ m, and dried at 110°C to obtain a negative electrode sheet with a coating thickness of 150 ⁇ m and a single-sided coating of a negative electrode active material layer.
  • Super P conductive carbon black
  • SBR styrene-butadiene rubber
  • the first conductive plate 30 is welded on the exposed area of the first current collector 210, and protective glue is pasted on the weld marks on both sides of the first conductive plate 30, such as the second layer 60 and the third layer 70.
  • the second layer 60 and the third layer 70 are single-sided adhesives respectively, and the adhesive layer of the second layer 60 and the adhesive layer of the third layer 70 are both arranged toward the first conductive plate 30.
  • Preparation of the second electrode sheet 22 The positive electrode active material lithium cobalt oxide (LiCoO 2 ), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) are mixed at a weight ratio of 97.5:1.0:1.5, and N-methylpyrrolidone (NMP) is added as a solvent to prepare a slurry with a solid content of 75wt%, and stirred evenly. The slurry is evenly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 12 ⁇ m, and then dried at 90°C to obtain a positive electrode sheet with a positive electrode active material layer thickness of 100 ⁇ m.
  • NMP N-methylpyrrolidone
  • the slurry is evenly coated on the surface, and then dried at 90°C to obtain a positive electrode sheet with a positive electrode active material layer coated on both sides.
  • the second conductive plate 40 is welded on the exposed area of the second current collector 220, and a protective adhesive is pasted on the second conductive plate 40.
  • the first electrode sheet 21, the isolation film 23 and the second electrode sheet 22 are stacked and wound in sequence to obtain the electrode assembly 20, and the isolation film 23 is selected to be a polyethylene (PE) film with a thickness of 15 ⁇ m.
  • PE polyethylene
  • PE polyethylene
  • Example 1 The difference from Example 1 lies in the relationship between L and d1 .
  • the third layer 70 is also extended to overlap with the first layer 50 in the first direction X.
  • the batteries of each embodiment and comparative example were subjected to a drop test, a drum drop test and a cycle test, and the corresponding test results are recorded in Table 1 and Table 2.
  • the battery If the voltage is less than 3.0V, the battery is judged to be failed; if there is no damage or leakage, and the open circuit voltage is higher than 3.0V, it is judged to be not failed, and continue to drop to the battery. The battery fails and then records the number of drops that have taken place when the battery fails.
  • Example 1 sets the second side 52 of the first layer 50 farther away from the edge of the electrode assembly 20 than the first side 51, so that the second side 52 can avoid the bending part of the first conductive plate 30, and the second layer 60 is extended to the first region 61 and overlaps with the first layer 50 in the first direction X. Therefore, the number of drops when failing in the drop test and the drum drop test is increased, that is, the battery reliability and service life of Example 1 are improved.
  • Example 1 has a smaller L value, and the number of drops when it fails in the drop test and the drum drop test is not much different.
  • the L value of Example 1 is smaller, the size of the gap C is smaller, and the electrolyte between the first layer 50 and the first wall 11 after injection is not easy to flow through the gap C and fully infiltrate the electrode assembly 20, so the first electrode plate 21 has slight purple spots, causing capacity decay.
  • Example 5 since the third layer 70 is also extended to overlap with the first layer 50 in the first direction X, the adhesive layer of the third layer 70 will at least partially adhere to the electrode assembly 20 during the drop test, making it difficult for the electrolyte between the first layer 50 and the first wall 11 after injection to flow through the gap C and fully infiltrate the electrode assembly 20.
  • the electrode assembly 20 is fully wetted, so the first electrode plate 21 also has slight purple spots, causing capacity decay.

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Abstract

一种电化学装置和电子装置。电化学装置包括壳体、电极组件、第一导电板、第一层和第二层。壳体包括第一壁和侧壁。电极组件为卷绕结构且包括第一极片。第一导电板包括第一导电区和第二导电区，分别连接第一极片和第一壁。第二导电区沿第二方向延伸，包括连接第一导电区的第一端部和与第一端部相对的第二端部。在第一方向上，第一层设于电极组件和第二导电区之间。从第一方向观察，第一层包括沿电极组件边缘弯曲延伸的第一边和连接第一边的第二边，第二边与电极组件存在重叠，第二边相较第一边远离电极组件的边缘以形成缺口。从第一方向观察，第二端部与第一层存在重叠，第二层的第一区域与第一层存在重叠。本申请可提高可靠性和使用寿命。

Description

电化学装置及电子装置 技术领域
本申请涉及储能技术领域，尤其涉及一种电化学装置和具有所述电化学装置的电子装置。
背景技术
电化学装置(如二次电池)在电子移动设备、电动工具及电动汽车等电子产品中有着广泛使用，人们对电化学装置的可靠性和安全性要求也越来越高。
电化学装置通常包括导电板，导电板连接极片和壳体，从而将极片的电极性经壳体引出。然而在由于非正常使用所造成的一些极端情况下，导电板的毛刺可能会刺穿隔离膜引发短路。在电化学装置发生机械滥用时，导电板也可能会发生疲劳断裂，进而导致电化学装置失效，影响电化学装置的安全可靠性和使用寿命。
发明内容
有鉴于此，有必要提供一种可靠性和安全性较高的电化学装置。
另，还有必要提供一种具有上述电化学装置的电子装置。
本申请第一方面提供一种电化学装置，包括壳体和电极组件。壳体包括第一壁和连接第一壁的侧壁。第一壁和侧壁围设形成容纳腔，电极组件收容于容纳腔内。自第一壁至电极组件的方向为第一方向。电极组件为卷绕结构，且包括第一极片、第二极片以及设于所述第一极片和所述第二极片之间的隔离膜。电化学装置还包括第一导电板和第一层。第一导电板包括相连接的第一导电区和第二导电区，第二导电区相较于第一导电区弯折。第一导电区连接第一极片，第二导电区连接第一壁。第二导电区包括连接于第一导电区的第一端部和与第一端部相对设置的第二端部。第二导电区自第一端部沿与第一方向垂直的第二方向延伸。第一层包含绝缘材料。在第一方向上，第一层设于电极组件以及第二导电区之间。从第一方向观察，第一层包括沿电极组件的边缘弯曲延伸的第一边以及连接于第一边的第二边。第二边与电极组件存在重叠，第二边相较于第一边更远离电极组件的边缘使第一层形成缺口。从第一方向观察，第二端部与第一层存在重叠。第二层包含绝缘材料。第二层包括覆盖第二导电区的第一区域，第一区域包括相连接的第一分区和第二分区。从第一方向观察，第一分区覆盖缺口，第二分区与第一层存在重叠。
本申请中，第一层用于隔绝电极组件和第一壁，减小电极组件与第一壁直接接触导致短路的可能性。第一层还可覆盖第二导电区的毛刺，减小上述毛刺刺穿隔离膜导致短路的可能性。而且，通过设置第二边相较于第一边更远离电极组件的边缘，当电化学装置发生机械滥用时，可以减小第一层对第一导电区和第二导电区之间的弯折处的挤压，从而减小了第一导电板上述弯折处在应力作用下发生断裂的可能性并导致电化学装置失效的可能 性，也减小第一导电板断裂后产生的尖端刺穿隔离膜引发短路的可能性。因此，电化学装置的可靠性和使用寿命得到提高。再者，本申请通过设置第二层的第一区域覆盖缺口，因此第一区域可配合第一层共同隔绝电极组件和第一壁，降低了由于第一层设置缺口后可能引发的短路可能性。另外第二层还可减小第二边处发生起翘的可能性，且使得第一层不容易在壳体内移动。
在一些可能实现方式中，从第一方向观察，第一端部位于缺口内。可以降低第一端部与侧壁接触摩擦的情况。
在一些可能的实现方式中，第一层朝向第一壁的表面包括第一凹部，第一层在第一凹部处与第二导电区相接。如此，在保证第一层厚度的前提下，可以减小第二导电区和第一层在第一方向上的总厚度，从而有利于提升能量密度。
在一些可能的实现方式中，第二边包括弯曲部。考虑第一层在切割时可能在第二边上形成豁口，通过设置第二边包括弯曲部，可减小在第一层的安装过程中上述豁口进一步扩大形成裂纹的可能性。
在一些可能的实现方式中，定义第三方向垂直于第一方向和第二方向，第二边在第三方向上的尺寸为d2，第二导电区在第三方向上的尺寸为d，d2>d。因此，可以使得第一层充分覆盖第二导电区，减小第二导电区的毛刺刺穿隔离膜导致短路的可能性。而且，可以使得第一层能够充分隔绝电极组件和第一壁，减小电极组件和第一壁直接接触短路的可能性。
在一些可能的实现方式中，第一极片包括第一集流体和设于第一集流体表面的第一活性物质层。第一集流体包括与第一活性物质层相离的第一部分，第一导电区连接于第一部分。如此，可减小第一导电区在第二方向上对电化学装置能量密度的影响，也减小了第一导电区对电极组件整体的平整度的影响。
在一些可能的实现方式中，在第二方向上，第一导电区设于第一部分朝向侧壁的表面。由于第一部分的阻挡，可减小第一导电区的毛刺刺穿隔离膜引发短路的可能性。
在一些可能的实现方式中，第一区域在第一方向上设于第二导电区和电极组件之间。第一区域用于配合第一层共同隔绝电极组件和第一壁以及共同覆盖第二导电区的毛刺，降低了发生短路的可能性。
在一些可能的实现方式中，第二层还包括连接第一区域的第二区域。第二区域覆盖第一导电区。第二区域用于覆盖第一导电区的毛刺，进一步减小上述毛刺刺穿隔离膜导致短路的可能性。
在一些可能的实现方式中，电化学装置还包括包含绝缘材料的第三层。第三层包括在第一方向上设于第二导电区和第一壁之间的第三区域。第三区域包括相连接的第三分区和第四分区。从第一方向观察，第三分区覆盖缺口，第四分区与第一层存在重叠。第三区域用于配合第一层共同隔绝电极组件和第一壁，降低了发生短路的可能性。
在一些可能的实现方式中，第三层还包括连接第三区域的第四区域。在第二方向上，第一导电区设于第二区域和第四区域之间。第四区域用于覆盖第一导电区的毛刺或焊印。
在一些可能的实现方式中，第二层包括层叠的胶粘层和基材。胶粘层包含绝缘材料。基材通过胶粘层粘接于第一导电板。由于第三层未粘接电极组件，注液后位于第一层和第一壁之间的电解液可以充分浸润电极组件，改善循环过程中的界面，降低了由于析锂、黑斑、紫斑等引起的容量衰减，提升了电化学装置的循环性能。
在一些可能的实现方式中，基材的材质选自聚酰亚胺或聚对苯二甲酸乙二脂的至少一种。在一些可能的实现方式中，胶粘层的绝缘材料选自丁二烯，异戊二烯、苯乙烯、甲基丙烯酸甲酯、甲基丙烯酸丁酯、丙烯酸异辛酯或丙烯酸丁酯的至少一种，使得胶粘层具有较佳的粘接性。
在一些可能的实现方式中，第四分区包括在第二方向上背离第三分区的第二端，第二端和侧壁在第二方向上的尺寸为d5，第一壁的半径为R，d5＜0.4R。如此，可以减小第三区域对第二导电板与第一壁之间的连接(焊接)区域的影响，即减小第三区域干涉到上述连接区域、导致连接区域失效的可能性。
在一些可能的实现方式中，定义第三方向垂直于第一方向和第二方向，第二边在第三方向上的尺寸为d2，第一区域在第三方向上的尺寸为d3，d2＜d3。如此，可以使得第一区域配合第一层共同隔绝电极组件和第一壁，降低了发生短路的可能性。
在一些可能的实现方式中，第二边与侧壁在第二方向上的距离为第一距离L，第二分区包括在第二方向上背离第一分区的第一端，第一端和侧壁在第二方向上的尺寸为d1，0.4d1＜L＜d1，从而减小了L值过小时，注液后位于第一层和第一壁之间的电解液不易充分浸润电极组件的可能性，因此提高了电极组件的浸润效果，从而改善循环过程中的界面、降低了由于析锂、黑斑、紫斑等引起的容量衰减，提升了电化学装置的循环性能。
在一些可能的实现方式中，从第一方向观察，第二导电区与电极组件的卷绕中心轴存在重叠。因此第二导电区在第二方向上具有较大的尺寸，有利于提高第二导电区和第一壁之间的连接强度。
在一些可能的实现方式中，电极组件的卷绕起始端设有空腔。从第一方向观察，第一层覆盖空腔。本申请不需为了使电解液充分浸润电极组件而在第一层对应于空腔的位置设置开孔，从而减小了第一导电区的焊印经上述开孔接触第二极片并对电化学装置寿命产生影响的短能性。
在一些可能的实现方式中，壳体还包括连接于侧壁且与第一壁相对设置的第二壁。第二壁上设有与第二壁电性绝缘的导电件。电极组件还包括电连接于第二极片的第二导电板，第二导电板连接导电件。如此，第一壁和导电件呈现相反的电极性，使得电化学装置可以为外部元件供电。
在一些可能的实现方式中，电化学装置为扣式电池，从第一方向观察，电极组件的边缘大致为圆形。由于扣式电池一般体积较小，在这种实施方式下不需要通过减小电极组件尺寸的方式减小第一层对第一导电板的弯折处的挤压，有利于提升能量密度。
本申请第二方面还提供一种电子装置，其包括如上电化学装置。电子装置通过上述电化学装置供电，且电化学装置通过设置第二边相较于第一边更远离电极组件的边缘，降低了第一导电板发生断裂的可能性，从而维持较高的可靠性和使用寿命。
附图说明
本申请的上述和/或附加的方面和优点从结合下面附图对实施例的描述中将变得明显和容易理解，其中：
图1A为本申请一实施方式的电化学装置的立体结构图。
图1B为图1A所示的电化学装置从第一方向观察时的俯视图。
图2A为图1A所示的电化学装置沿II-II的剖视图。
图2B为图2A所示的电化学装置的电极组件卷绕前第一极片从第五方向观察时的结构示意图。
图2C为图2B所示的第一极片从第一方向观察时的结构示意图。
图3为图1B所示的电化学装置沿III-III的剖视图。
图4为图3所示的电化学装置于A处的放大图。
图5为图1B所示的电化学装置沿V-V的剖视图。
图6为图1A所示的电化学装置去掉壳体的第一壁后沿第一方向观察时的仰视图。
图7为图6所示的电化学装置去掉第三层后沿第一方向观察时的仰视图。
图8为图7所示的电化学装置的第二层的剖视图。
图9为本申请另一实施方式的电化学装置的结构示意图。
图10为本申请再一实施方式的电化学装置的剖视图。
图11为本申请一实施方式的电子装置的结构示意图。
主要元件符号说明
电子装置            1
壳体                10
第一壁              11
第二壁              12
侧壁                13
导电件              14
第一绝缘层          15
第二绝缘层          16
电极组件            20
第一段              20a
第二段              20b
第一极片         21
第二极片            22
隔离膜              23
第一导电板          30
第一导电区          31
第二导电区          32
第二导电板          40
第三导电区          41
第四导电区          42
第一层              50
第一边              51
第二边              52
第二层              60
第一区域            61
第二区域            62
第三层              70
第三区域            71
第四区域            72
第四层              80
电化学装置          100
第一开口            120
第一边缘            131
第二边缘            132
导电部              141
安装部              142
密封件              143
第一集流体          210
第一活性物质层      211
第二活性物质层      212
第二集流体          220
第三活性物质层      221
第四活性物质层      222
第一面            301
第二面               302
第一端部             321
第二端部             322
第三端部             421
第四端部             422
第五表面             501
第六表面             502
第一凹部             503
第一分区             611
第二分区             612
胶粘层               601
基材                 602
第三分区             711
第四分区             712
第二开口             1410
卷绕起始端           2001
第一部分             2100
第一表面             2101
第二表面             2102
第二部分             2200
第三表面             2201
第四表面             2202
第一端               6120
第二端               7120
容纳腔               S1
空腔                 S2
卷绕中心轴           O
缺口                 C
尺寸                 d、d1、d2、d3、d4、d5
半径                 R
第一距离             L
第一交点            P1
第二交点            P2
第一方向            X
第二方向            Y
第三方向            Z
第四方向            Y’
第五方向            Z’
如下具体实施方式将结合上述附图进一步说明本申请。
具体实施方式
下面对本申请实施例中的技术方案进行清楚、详细地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同。在本申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请。
下文，将详细地描述本申请的实施方式。但是，本申请可体现为许多不同的形式，并且不应解释为限于本文阐释的示例性实施方式。而是，提供这些示例性实施方式，从而使本申请透彻的和详细的向本领域技术人员传达。
另外，为了简洁和清楚，在附图中，各种组件、层的尺寸或厚度可被放大。遍及全文，相同的数值指相同的要素。如本文所使用，术语“及/或”、“以及/或者”包括一个或多个相关列举项目的任何和所有组合。另外，应当理解，当要素A被称为“连接”要素B时，要素A可直接连接至要素B，或可能存在中间要素C并且要素A和要素B可彼此间接连接。
进一步，当描述本申请的实施方式时使用“可”指“本申请的一个或多个实施方式”。
本文使用的专业术语是为了描述具体实施方式的目的并且不旨在限制本申请。如本文所使用，单数形式旨在也包括复数形式，除非上下文另外明确指出。应进一步理解，术语“包括”，当在本说明书中使用时，指存在叙述的特征、数值、步骤、操作、要素和/或组分，但是不排除存在或增加一个或多个其他特征、数值、步骤、操作、要素、组分和/或其组合。
空间相关术语，比如“上”等可在本文用于方便描述，以描述如图中阐释的一个要素或特征与另一要素(多个要素)或特征(多个特征)的关系。应理解，除了图中描述的方向之外，空间相关术语旨在包括设备或装置在使用或操作中的不同方向。例如，如果将图中的设备翻转，则描述为在其他要素或特征“上方”或“上”的要素将定向在其他要素或特征的“下方”或“下面”。因此，示例性术语“上”可包括上面和下面的方向。应理解，尽管术语第一、第二、第三等可在本文用于描述各种要素、组分、区域、层和/或部分，但是这些要素、组分、区域、层和/或部分不应受这些术语的限制。这些术语用于区分一个要素、组分、区域、层或部分与另一要素、组分、区域、层或部分。因此，下面讨论的第一要素、组分、区域、层或部分可称为第二要素、组分、区域、层或部分，而不背离示例性实施方式的教导。
如本文中所使用，属于“平行”、“垂直”用于描述两个部件之间的理想状态。实际生产或使用的状态中，两个部件之间可以存在近似于平行或垂直的状态。举例来说，结合数值描述，平行可以指代两直线之间夹角范围在±10°之间，平行也可以指代两平面的二面角范围在±10°之间，平行还可以指代直线与平面之间的夹角范围在±10°之间。垂直可以指代两直线之间夹角范围在90±10°之间，垂直也可以指代两平面的二面角范围在90±10°之间，垂直还可以指代直线与平面之间的夹角范围在90±10°之间。被描述“平行”、“垂直”的两个部件可以不是绝对的直线、平面，也可以大致呈直线或平面，从宏观来看整体延伸方向为直线或平面即可认为部件为“直线”或“平面”。
在本申请中，参数数值之间的大于、小于或不等于设计关系，需要排除测量设备的合理误差。
请参阅图1A至图2A和图3，本申请一实施方式提供一种电化学装置100，包括壳体10、电极组件20和电解液(图未示)。壳体10包括第一壁11、第二壁12和侧壁13。第一壁11和第二壁12在第一方向X上相对设置。从第一方向X观察，第一壁11可以大致呈圆形，第二壁12也可以大致呈圆形。第一壁11和第二壁12可以平行设置且均垂直于第一方向X。侧壁13的第一边缘131连接第一壁11，侧壁13的第二边缘132连接第二壁12，使得壳体10内形成大致呈圆柱形的容纳腔S1。从第一方向X观察，第一壁11覆盖容纳腔S1。电极组件20和电解液收容于容纳腔S1内，第一方向X也为从第一壁11至电极组件20的方向。在一些实施例中，电化学装置100为扣式电池。侧壁13和第二壁12可一体成型，第二壁12和侧壁13之间可焊接或卡接固定。其中，壳体10可整体为钢材质。在一些实施例中，钢壳体10包括元素Fe和C，钢壳体还可以包括元素Ni、Co、Al、Mn、Cr、Cu、Mg、Mo、S、Si、Ti、V、Pb、Sb、N、P中的一种或几种。例如，第一壁11为钢材质，第二壁12和第二壁12也为钢材质。
在一些实施例中，第二壁12上还可设有与第二壁12电性绝缘的导电件14。例如，第二壁12设有与容纳腔S1连通的第一开口120，导电件14可通过粘接或者铆接等方式安装于第一开口120。导电件14可包括相连接的导电部141和安装部142。导电部141设于第一开口120内，安装部142设于第二壁12背离第一壁11的表面上。进一步地，导电件14和第二壁12之间可设有第一绝缘层15，第一绝缘层15用于使导电件14和第二壁12电性隔绝。第一绝缘层15可通过过盈配合方式固定于导电件14和第二壁12之间。在其它实施例中，第一绝缘层15还可通过铆接等方式固定于导电件14和第二壁12之间。其中，第一绝缘层15的材质可为聚乙烯、聚丙烯、丙烯-乙烯共聚物、聚醚醚酮、聚偏氟乙烯或聚四氟乙烯。
在一些实施例中，导电部141可设有第二开口1410，从第一方向X观察，第二开口1410位于第一开口120内。电解液可经由第二开口1410流入容纳腔S1内。为了减小注液后的漏液风险，可在导电部141上安装密封件143，且密封件143覆盖第二开口1410。
如图2A和图3所示，电极组件20为卷绕结构且具有卷绕中心轴O。第一方向X在一些实施例中也为电极组件20的卷绕中心轴O的方向。电极组件20包括第一极片21、第二 极片22以及设于第一极片21和第二极片22之间的隔离膜23。隔离膜23用于防止第一极片21和第二极片22直接接触，从而降低第一极片21和第二极片22发生接触短路的可能性。为简化起见，隔离膜23以虚线(间隔的多个短线组成)示出。在一些实施例中，从第一方向X观察，电极组件20的边缘也可以大致呈圆形。在一些实施例中，卷绕后，隔离膜23位于电极组件20的至少部分最外层。如，隔离膜23位于电极组件20的最外层。隔离膜23能够形成保护层，减小该部分隔离膜23内侧的极片由于磨损带来的短路风险，从而增加电极组件20耐机械冲击的能力。在另一些实施例中，第一极片21或第二极片22也可以位于电极组件20的最外层。
其中，电极组件20的卷绕起始端2001可设有空腔S2。卷绕中心轴O沿第一方向X穿过空腔S2。制备时可通过卷针(图未示)对第一极片21、隔离膜23和第二极片22进行卷绕，卷绕形成电极组件20后将卷针抽取出来，从而在电极组件20内形成上述空腔S2。在一些实施例中，如图2A和图3所示，隔离膜23的最内圈为电极组件20的卷绕起始端2001。
如图2B和图2C所示，当第一极片21展开后，根据相互垂直的第一方向X、第四方向Y’和第五方向Z’建立另一三维坐标系，定义第四方向Y’为卷绕前第一极片21的延伸方向，第五方向Z’为第一极片21展开后的厚度方向。请一并参照图2A至图3，第一极片21包括依次堆叠的第一活性物质层211、第一集流体210和第二活性物质层212。第五方向Z’即为展开后第一集流体210和第一活性物质层211的堆叠方向。其中，第一集流体210包括相对设置的第一表面2101和第二表面2102，第一表面2101相较于第二表面2102更远离卷绕中心轴O，第一活性物质层211设于第一表面2101，第二活性物质层212设于第二表面2102。第一集流体210可包含铝或镍。在一些实施例中，第一极片21为负极时，第一集流体210包含铜。第一活性物质层211和第二活性物质层212均包含活性物质，其可选自石墨类材料、合金类材料、锂金属及其合金中的至少一种。石墨类材料可选自人造石墨、天然石墨中的至少一种；合金类材料可选自硅、氧化硅、锡、硫化钛中的至少一种。
第二极片22包括堆叠设置的第三活性物质层221、第二集流体220和第四活性物质层222。其中，第二集流体220包括相对设置的第三表面2201和第四表面2202，第三表面2201相较于第四表面2202更靠近卷绕中心轴O，第三活性物质层221设于第三表面2201，第四活性物质层222设于第四表面2202。第二集流体220可包含铜、镍或碳基导电物。在一些实施例中，第二极片22为正极时，第二集流体220包含铝箔，铝箔的强度较弱但具有较好的导电性能。第三活性物质层221和第四活性物质层222均包含活性物质，如包含钴酸锂、锰酸锂、镍酸锂、镍钴锰酸锂、磷酸铁锂、磷酸锰铁锂、磷酸钒锂、磷酸钒氧锂、富锂锰基材料或镍钴铝酸锂中的至少一种。
隔离膜23包括聚乙烯、聚丙烯、聚偏氟乙烯、聚对苯二甲酸乙二醇酯、聚酰亚胺或芳纶中的至少一种。
请一并参照图3和图4，电化学装置100还包括第一导电板30。其中图3为图1B所示的电化学装置沿III-III的剖视图，图4为图3所示的电化学装置于A处的放大图。结合 图1A和图1B可知，当沿着III-III作电化学装置100的横截面时，该横截面经过第一导电板30，即图3和图4示出的横截面包含第一导电板30。第一导电板30包括相连接的第一导电区31和第二导电区32。第二导电区32相较于第一导电区31弯折。结合参照图2B和图2C所示，第一导电区31连接第一极片21(如，连接第一极片21的第一集流体210)，第一导电区31可以沿着第一方向X伸出第一极片21。第二导电区32连接第一壁11。在第一方向X上，第二导电区32设于第一壁11和电极组件20之间。其中，第二导电区32包括连接于第一导电区31的第一端部321和背离第一端部321的第二端部322，第二导电区32自第一端部321沿着第二方向Y延伸。如，第二方向Y为从第一端部321至第二端部322的方向。从垂直于第一方向X和第二方向Y的第三方向Z观察，第一导电板30于第一端部321处发生弯折，第一导电区31可大致垂直于第二导电区32。从第一方向X观察，第一导电区31和第二导电区32之间的弯折处与电极组件20存在重叠。其中，如图4所示，第一导电板30包括朝向壳体10的第一面301和朝向电极组件20的第二面302。由于第一导电板30发生弯折，因此第一面301和第二面302并非平面，第一面301和第二面302分别为弯折的面。
在一些实施例中，第一集流体210包括第一部分2100，第一部分2100的第一表面2101与第一活性物质层211相离，第一导电区31连接于第一部分2100的第一表面2101。通过设置第一导电区31连接于与第一活性物质层211相离的第一部分2100，减小了第一导电区31在第二方向Y上对电化学装置100能量密度的影响，也减小了第一导电区31对电极组件20整体的平整度的影响。进一步地，在第二方向Y上，第一导电区31可设于第一部分2100朝向侧壁13的表面(即第一部分2100的第一表面2101)。通过设置第一导电区31设于第一部分2100朝向侧壁13的表面，由于第一部分2100的阻挡，可减小第一导电区31的毛刺(如，毛刺可以是第一导电板30在裁切过程中形成，但本申请不作限制)刺穿隔离膜23、导致第一极片21和第二极片22直接接触引发短路的可能性。第一部分2100的第二表面2102也可以与第二活性物质层212相离，第一部分2100此时可以为第一极片21的尾部空箔区。为提高连接强度，可以设置第一导电区31焊接于第一部分2100的第一表面2101，且第二导电区32焊接于第一壁11。
在一些实施例中，从第一方向X观察，第二导电区32与电极组件20的卷绕中心轴O存在重叠。由于第二导电区32延伸至与卷绕中心轴O重叠，第二导电区32在第二方向Y上具有较大的尺寸，有利于提高第二导电区32和第一壁11之间的连接强度。
请参照图5，电化学装置100还包括第二导电板40。其中图5为图1B所示的电化学装置沿V-V的剖视图。结合图1A和图1B可知，当沿着V-V作电化学装置100的横截面时，该横截面经过第二导电板40，即图5示出的横截面包含第二导电板40。第二导电板40包括相连接的第三导电区41和第四导电区42。第三导电区41连接第二极片22(如连接第二极片22的第二集流体220)，第三导电区41可以沿着第一方向X伸出第二极片22。第四导电区42连接导电件14(如，连接导电件14的导电部141)。在第一方向X上，第四导电区42设于第二壁12和电极组件20之间。其中，第四导电区42包括连接于第三导电 区41的第三端部421和背离第三端部421的第四端部422，第四导电区42自第三端部421沿着第二方向Y延伸。
在一些实施例中，第二集流体220包括第二部分2200，第二部分2200第三表面2201与第三活性物质层221相离，第三导电区41连接于第二部分2200的第三表面2201。通过设置第三导电区41连接于与第三活性物质层221相离的第二部分2200，减小了第三导电区41在第二方向Y上对电化学装置100能量密度的影响，也减小了第三导电区41对电极组件20整体的平整度的影响。第二部分2200的第四表面2202也可以与第四活性物质层222相离，第二部分2200此时可以为第二极片22的尾部空箔区。为提高连接强度，可以设置第三导电区41焊接于第二部分2200的第三表面2201，第四导电区42焊接于导电件14。
通过设置第二导电区32连接第一壁11以及设置第四导电区42连接导电件14，第一壁11和导电件14呈现相反的电极性，使得电化学装置100可以为外部元件(图未示)供电。其中，当第一极片21为负极极片且第二极片22为正极极片时，第一壁11、侧壁13和第二壁12整体呈负极性，导电件14呈正极性。
如图3至图5所示，电化学装置100还包括包含绝缘材料的第一层50。在第一方向X上，第一层50设于电极组件20以及第二导电区32之间。第一层50用于隔绝电极组件20和第一壁11，减小第二极片22与第一壁11直接接触导致短路的可能性。第一层50还可覆盖第二导电区32的毛刺(如，毛刺可以是第一导电板30在裁切过程中形成，但本申请不作限制)，减小上述毛刺刺穿隔离膜23、导致第一极片21和第二极片22直接接触导致短路的可能性。其中，第一层50的绝缘材料可以选自聚丙烯、聚乙烯、聚偏二氟乙烯、偏二氟乙烯-六氟丙烯共聚物、聚甲基丙烯酸甲酯或聚乙二醇中至少一种。
如图4所示，在一些实施例中，第一层50包括朝向第一壁11的第五表面501和朝向电极组件20的第六表面502。第五表面501和第六表面502相对设置。第一层50的第五表面501包括第一凹部503，且第一凹部503沿第一方向X未贯穿第六表面502。至少部分第二导电区32设于第一凹部503内，且第二导电区32的第二面302与第一凹部503的底面相接。在第一方向X上，第二导电区32的第二面302位于第一层50的第五表面501和第六表面502之间。为便于将第二导电区32焊接于第一壁11，在第一方向X上，第二导电区32的第一面301可相较于第一层50的第五表面501更远离电极组件20。如图4所示，可以设置包含第二端部322的部分第二导电区32设于第一凹部503内。第一层50在第一凹部503处与第二导电区32相接。如此，在保证第一层50厚度的前提下，可以减小第二导电区32和第一层50在第一方向X上的总厚度，从而有利于提升能量密度。其中，请进一步参照图6和图7，从第一方向X观察，第一凹部503的边缘可与第二导电区32的边缘存在重叠。如此，在使得部分第二导电区32能够设于第一凹部503内的前提下，还减小了第一凹部503尺寸过大对第一层50隔绝效果的影响，从而使得第一层50在开设第一凹部503后能够充分隔绝电极组件20和第一壁11。
请参阅图6和图7，从第一方向X观察，第一层50包括沿电极组件20的边缘弯曲延伸的第一边51以及连接于第一边51的第二边52。图6和图7示出电极组件20的最外层即隔离膜23，隔离膜23为从第一方向X观察时电极组件20的边缘。其中，可以将从第一方向X观察时电极组件20的边缘划分为相连接的第一段20a和第二段20b(从第一方向X观察，电极组件20的边缘与第二边52相较于第一交点P1和第二交点P2，第一交点P1和第二交点P2将电极组件20的边缘划分为第一段20a和第二段20b)，第一边51与第一段20a相对设置，第二边52与第二段20b相对设置。本申请中，第一边51沿电极组件20的边缘弯曲延伸，指的是第一边51的延伸方向与第一段20a的延伸方向一致或基本一致。当从第一方向X观察电极组件20的边缘大致呈圆形时，第一段20a为弧段，即弯曲的圆周的一部分，第一边51也可以对应地设置为弧段。当电极组件20的边缘形状变更时，第一边51的形状也可以有所不同。如图6和图7所示，为了使第一层50充分隔绝第二极片22与第一壁11，从第一方向X观察，第一边51可以位于电极组件20外部，此时第一边51所界定的圆周的半径大于第一段20a所界定的圆周的半径，且第一边51与第一段20a之间的距离沿着第一边51的延伸方向可以保持一致或基本一致。在另一些实施例中，从第一方向X观察时，第一边51也可以与第一段20a大致重合。
从第一方向X观察，第二边52与电极组件20存在重叠，第二边52相较于第一边51更远离电极组件20的边缘。因此，第二边52偏离第一边51所界定的圆周，第二边52位于第一边51所界定的圆周的内部。第二边52可以为直线，也可以包含曲线部分。在一些实施例中，第二边52为直线且沿着第三方向Z延伸。从第一方向X观察，第二导电区32的第一端部321与第一层50在第二方向Y上相距设置，第二端部322和第一层50存在重叠。从第一方向X观察，第二导电区32自第一端部321沿着第二方向Y延伸至超出第二边52。其中，由于第二边52相较于第一边51更远离电极组件20的边缘，第二边52偏离第一边51界定的圆周，因此第一层50从第一方向X观察时具有缺口C，第二边52即为缺口C的边缘。从第一方向X观察，第二导电区32的第一端部321可以位于缺口C内，从而可以降低第一端部321与侧壁13接触摩擦的可能性。
如图6和图7所示，在一些实施例中，第二边52在第三方向Z上的尺寸为d2，第二导电区32在第三方向Z上的尺寸为d，则d2>d。因此，可以使得第一层50充分覆盖第二导电区32，减小第二导电区32的毛刺刺穿隔离膜23、导致第一极片21和第二极片22直接接触短路的可能性。而且由于第二边52尺寸较大，因此第一层50能够充分隔绝第二极片22和第一壁11，减小第二极片22和第一壁11直接接触短路的可能性。
其中，d、d2的测量步骤可以是：(1)采用X射线从第一方向X对电化学装置100进行二维投影和扫描测试，仪器可以采用本领域技术人员公知的仪器或设备(例如GE Phoenixvtomex S设备)，从而获得CT图；(2)采用卡尺或其它合适的量具直接测量d、d2的数值。
d、d2的测量步骤还可以是：(1)将电化学装置100以0.2C放电至2.75V；(2)沿垂直于第一方向X的截面切割壳体10的侧壁13临近第一边缘131的位置，当大部分侧壁13 与第一壁11分离后，将第一壁11相较于第一层50打开，此时第二导电区32仍连接于第一壁11；(3)采用卡尺或其它合适的量具直接测量d、d2的数值。
d、d2的测量步骤还可以是：(1)将电化学装置100以0.2C放电至2.75V；(2)配置树脂组合物，其由水晶胶树脂基体(如环氧树脂)、催化剂及固化剂按照一定比例调配而成；(3)将树脂组合物倒入模具中，并将电化学装置100置于模具中，再继续缓慢倒入树脂组合物，使得将电化学装置100完全浸没于树脂组合物中；(4)将电化学装置100取出，然后静置至树脂组合物凝固；(5)打磨壳体10的第一壁11直至第二导电区32露出于打磨面；(6)采用卡尺或其它合适的量具直接测量d、d2的数值。
如图4和图7所示，电化学装置100还包括包含绝缘材料的第二层60。第二层60覆盖第一导电板30，从第一方向X观察，第二层60覆盖缺口C，从而进一步减小由于第一层50设置缺口C后可能引发的短路可能性。其中，第二层60包括覆盖第二导电区32的第一区域61。从第一方向X观察，第一区域61覆盖缺口C。在一些实施例中，第二层60覆盖第一导电板30的第二面302，第一区域61在第一方向X上设于第二导电区32和电极组件20之间。第一区域61用于进一步隔绝电极组件20和第一壁11，从而减小第二极片22与第一壁11直接接触导致短路的可能性，当第一区域61在第一方向X上设于第二导电区32和电极组件20之间时，第二层60还可覆盖第二导电区32的毛刺，减小上述毛刺刺穿隔离膜23、导致第一极片21和第二极片22直接接触导致短路的可能性。即，第二层60的第一区域61用于配合第一层50共同隔绝电极组件20和第一壁11以及共同覆盖第二导电区32的毛刺，降低了发生短路的可能性。在本实施例中，第一区域61包括相连接的第一分区611和第二分区612。从第一方向X观察，第一分区611位于第二导电区32和电极组件20之间，第一分区611与缺口C存在重叠。从第一方向X观察，第二分区612与第一层50存在重叠。通过设置第二分区612与第一层50存在重叠，使得第一区域61能够充分覆盖缺口C。第二分区612也可设于第一凹部503内。其中，第二层60的绝缘材料可以选自聚丙烯、聚乙烯、聚偏二氟乙烯、偏二氟乙烯-六氟丙烯共聚物、聚甲基丙烯酸甲酯或聚乙二醇中至少一种。其中，第二层60可以是包含绝缘材料的单面胶或双面胶。在其它实施例中，第二层60也可以为陶瓷涂层。
如图4和图7所示，第二边52与侧壁13在第二方向Y上的距离为第一距离L，第二分区612具有在第二方向Y上背离第一分区611的第一端6120，第一端6120与侧壁13在第二方向Y上的尺寸为d1，L＜d1。可以理解，L为第二边52与位于缺口C背离第二边52一侧的部分侧壁13在第二方向Y上的距离；d1为第一端6120与位于缺口C背离第二边52一侧的部分侧壁13在第二方向Y上的距离。其中，可采用与d、d2相似的测量步骤测量L、d1。
如图7所示，在一些实施例中，第二边52在第三方向Z上的尺寸为d2，第一区域61在第三方向Z上的尺寸为d3，d2＜d3。如此，可以使得第一区域61在第三方向Z上充分覆盖缺口C，从而使得第一区域61用于配合第一层50共同隔绝电极组件20和第一壁11以及共同覆盖第二导电区32的毛刺，降低了发生短路的可能性。
进一步地，在一些实施例中，第二层60还可包括连接第一区域61的第二区域62。第二区域62用于覆盖第一导电区31的毛刺，进一步减小上述毛刺刺穿隔离膜23、导致第一极片21和第二极片22直接接触导致短路的可能性。可以理解，为简化起见，图7仅示出第二层60的第一区域61，未示出第二层60的第二区域62。
考虑到从第一方向X观察时第一导电区31和第二导电区32之间的弯折处与电极组件20存在重叠，本申请通过设置第二边52相较于第一边51更远离电极组件20的边缘，使得第二边52可以避开第一导电区31和第二导电区32之间的弯折处。如此，当电化学装置100发生机械滥用(如撞击、跌落)时，可以减小第一层50对第一导电区31和第二导电区32之间的弯折处的干涉和挤压，从而减小了第一导电板30上述弯折处在应力作用下发生断裂的可能性并导致电化学装置100失效的可能性，也减小第一导电板30断裂后产生的尖端刺穿隔离膜23、导致第一极片21和第二极片22直接接触引发短路的可能性。因此，电化学装置100的可靠性和使用寿命得到提高。当电化学装置100为扣式电池时，由于扣式电池一般体积较小，这种实施方式下不需要通过减小电极组件20尺寸的方式减小第一层50对第一导电板30的弯折处的挤压(例如，通过减小电极组件20的尺寸，相应增大电极组件20和壳体10之间的间隙，在发生机械滥用时可以为电极组件20提供更大的缓冲空间，减小第一层50对第一导电板30的弯折处的挤压)，有利于提升能量密度。
再者，本申请通过设置第二层60的第一区域61覆盖缺口C，因此第一区域61可配合第一层50共同隔绝电极组件20和第一壁11，降低了由于第一层50设置缺口C后可能引发的短路可能性。另外，由于第一区域61覆盖第一层50的第二边52，因此第二层60还可减小第二边52处发生起翘的可能性，且使得第一层50不容易在壳体10内移动。
请一并参阅图4、图7和图8，在一些实施例中，第二层60为粘接于第一导电板30的单面胶。第二层60包括层叠的胶粘层601和基材602。胶粘层601包含绝缘材料。基材602通过胶粘层601粘接于第一导电板30。通过设置第二层60覆盖第一层50的缺口C，由于第二层60未粘接电极组件20，注液后位于第一层50和第一壁11之间的电解液可以流经缺口C并充分浸润电极组件20，从而改善循环过程中的界面，降低了由于析锂、黑斑、紫斑等引起的容量衰减，提升了电化学装置100的循环性能。进一步地，在一些实施例中，可以设置0.4d1＜L＜d1，从而减小了L值过小时缺口C尺寸较小、注液后位于第一层50和第一壁11之间的电解液不易流经缺口C并充分浸润电极组件20的可能性，因此提高了电极组件20的浸润效果，从而改善循环过程中的界面、降低了由于析锂、黑斑、紫斑等引起的容量衰减。其中，基材602的材质选自聚酰亚胺或聚对苯二甲酸乙二脂的至少一种。胶粘层601的绝缘材料可选自丁二烯，异戊二烯、苯乙烯、甲基丙烯酸甲酯、甲基丙烯酸丁酯、丙烯酸异辛酯或丙烯酸丁酯的至少一种。
由于通过设置第二层60为粘接于第一导电板30的单面胶并可进一步合理设置d1和L的关系，使得注液后位于第一层50和第一壁11之间的电解液可以流经缺口C并充分浸润电极组件20，因此在一些实施例中，可以设置从第一方向X观察时，第一层50覆盖电极组件20的空腔S2。即，本申请不需为了使电解液充分浸润电极组件20而在第一层50对 应于空腔S2的位置设置开孔，从而减小了第一导电区31的焊印或焊渣经上述开孔接触第二极片22并对电化学装置100寿命产生影响的可能性。
如图3和图4所示，在一些实施例中，电化学装置100还包括包含绝缘材料的第三层70。第三层70覆盖第一导电板30的第一面301，从第一方向X观察，第三层70覆盖至少部分缺口C，从而进一步减小由于第一层50设置缺口C后可能引发的短路可能性。其中，第三层70包括在第一方向X上设于第二导电区32和第一壁11之间的第三区域71。从第一方向X观察，第三区域71覆盖至少部分缺口C。第三区域71用于进一步隔绝电极组件20和第一壁11，从而减小第二极片22与第一壁11直接接触导致短路的可能性。即，第三层70的第三区域71用于配合第一层50共同隔绝电极组件20和第一壁11，降低了发生短路的可能性。在本实施例中，第三区域71包括相连接的第三分区711和第四分区712。从第一方向X观察，第三分区711与缺口C存在重叠。从第一方向X观察，第四分区712与第一层50存在重叠。通过设置第四分区712与第一层50存在重叠，使得第三区域71和第一区域61能够共同充分覆盖缺口C，进一步减小短路的可能性。其中，第三层70的绝缘材料可以选自聚丙烯、聚乙烯、聚偏二氟乙烯、偏二氟乙烯-六氟丙烯共聚物、聚甲基丙烯酸甲酯或聚乙二醇中至少一种。
其中，第四分区712具有在第二方向Y背离第三分区711的第二端7120，第二端7120与侧壁13在第二方向Y上的尺寸为d5，L＜d5。在一些实施例中，d5可大致等于d1。可以理解，d5为第二端7120与位于缺口C背离第二边52一侧的部分侧壁13在第二方向Y上的距离。
如图4和图6所示，在一些实施例中，第一壁11的半径为R(可以理解，图6示出的侧壁13的半径R即为第一壁11的半径)，则d5＜0.4R。如此，可以减小第三区域71对第二导电板40与第一壁11之间的连接区域(如，焊接区域)的影响，即减小第三区域71干涉到上述连接区域、导致连接区域失效的可能性。
在一些实施例中，第二边52在第三方向Z上的尺寸为d2，第三区域71在第三方向Z上的尺寸为d4，d2＜d4。如此，可以使得第三区域71在第三方向Z上充分覆盖缺口C，从而使得第三区域71用于配合第一层50共同隔绝电极组件20和第一壁11，降低了发生短路的可能性。在一些实施例中，d4可大致等于d3。
如图4和图6所示，进一步地，在一些实施例中，第三层70还可包括连接第三区域71的第四区域72。如图4所示，在第二方向Y上，第四区域72位于第一导电区31的第一面301。第四区域72用于覆盖第一导电区31的毛刺或焊印。其中，第三层70可以是包含绝缘材料的单面胶或双面胶。在其它实施例中，第三层70也可以为陶瓷涂层。可以理解，为简化起见，图6仅示出第三层70的第三区域71，未示出第三层70的第四区域72。
如图3至图5所示，在一些实施例中，电化学装置100还可包括包含绝缘材料的第四层80。在第一方向X上，第四层80设于电极组件20以及侧壁13之间。第四层80可减小第二极片22与侧壁13直接接触(如，第二极片22的毛刺刺穿最外层的隔离膜23并与侧壁13接触)导致短路的可能性。如图2A所示，第四层80可以为连续的环形结构。在一 些实施例中，第四层80的绝缘材料可以选自聚丙烯、聚乙烯、聚偏二氟乙烯、偏二氟乙烯-六氟丙烯共聚物、聚甲基丙烯酸甲酯或聚乙二醇中至少一种。
请参阅图9，本申请另一实施方式还提供一种电化学装置200，与上述电化学装置100不同之处在于，第二边52包括弯曲部。考虑第一层50在切割缺口C时可能在第二边52上形成豁口，通过设置第二边52包括弯曲部，可减小在第一层50的安装过程中上述豁口进一步扩大形成裂纹的可能性。
请参阅图10，本申请另一实施方式还提供一种电化学装置300，与上述电化学装置100不同之处在于，第一壁11与第二壁12电性隔绝。例如，侧壁13和第二壁12可一体成型，第二壁12和侧壁13之间可通过第二绝缘层16粘接固定，第二绝缘层16使得第一壁11和侧壁13之间电性隔绝，第一壁11和第二壁12之间也电性隔绝。
此时，第二导电板40的第四导电区42连接第二壁12。第一壁11和第二壁12呈现相反的电极性，使得电化学装置300可以为外部元件供电。其中，当第一极片21为负极极片且第二极片22为正极极片时，第一壁11和侧壁13呈负极性，第二壁12呈正极性。
其中，本申请的电化学装置100、200、300包括所有能够发生电化学反应的装置。具体的，电化学装置100、200、300包括所有种类的原电池、二次电池、燃料电池、太阳能电池和电容器(例如超级电容器)。可选地，电化学装置100、200、300可以为锂二次电池，包括锂金属二次电池、锂离子二次电池、锂聚合物二次电池和锂离子聚合物二次电池。
请参阅图11，本申请一实施方式还提供一种电子装置1，包括上述电化学装置100(或电化学装置200、300)。电子装置1通过上述电化学装置100供电，且电化学装置100通过设置第二边52相较于第一边51更远离电极组件20的边缘，降低了第一导电板30发生断裂的可能性，从而维持较高的可靠性和使用寿命。在一实施方式中，本申请的电子装置1可以是，但不限于笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
以下通过具体实施例和对比例对本申请提供的电化学装置100的性能进行说明。其中，以电化学装置100为扣式锂离子电池为例并结合具体制备过程和测试方法对本申请进行说明，本领域技术人员应理解，本申请中描述的制备方法仅是实例，其他任何合适的制备方法均在本申请的范围内。
实施例1
(1)第一极片21的制备：将负极活性材料人造石墨、导电炭黑(Super P)、丁苯橡胶(SBR)按照重量比96:1.5:2.5进行混合，加入去离子水作为溶剂，调配成重量百分比为70wt％的浆料，并搅拌均匀。将浆料均匀涂覆在厚度为10μm的负极集流体铜箔的一个表面上，110℃条件下烘干，得到涂层厚度为150μm的单面涂覆有负极活性材料层的负极极片。在该负极极片的另一个表面上重复以上步骤，得到双面涂覆有负极活性材料层的负极极片。接着， 在第一集流体210露出的区域上焊接第一导电板30，并在第一导电板30两侧的焊印上粘贴保护胶，如第二层60和第三层70，第二层60和第三层70分别为单面胶，第二层60的胶粘层和第三层70的胶粘层均朝向第一导电板30设置。
(2)第二极片22的制备：将正极活性材料钴酸锂(LiCoO2)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成固含量为75wt％的浆料，并搅拌均匀。将浆料均匀涂覆在厚度为12μm的正极集流体铝箔的一个表面上，然后90℃条件下烘干，得到正极活性材料层厚度为100μm的正极极片。将浆料均匀涂覆在该表面上，然后90℃条件下烘干，得到双面涂覆有正极活性材料层的正极极片。接着，在第二集流体220露出的区域上焊接第二导电板40，并在第二导电板40上粘贴保护胶。
(3)电解液的制备：在干燥氩气气氛中，首先将有机溶剂碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)以质量比EC:EMC:DEC＝30:50:20混合，然后向有机溶剂中加入锂盐六氟磷酸锂(LiPF6)溶解并混合均匀，得到锂盐的浓度为1.15mol/L的电解液。
(4)电池的制备：将第一极片21、隔离膜23和第二极片22依次层叠卷绕得到电极组件20，隔离膜23选用厚度为15μm的聚乙烯(PE)膜。然后将第一层50和电极组件20依次置于第一壁11和侧壁13形成的容纳腔S1内，将第一导电板30和第二导电板40分别进行弯折、焊接，其中第一层50的第二边52相较于第一边51更远离电极组件20的边缘，使得第二边52可以避开第一导电板30的弯折处，且第二层60延长至第一区域61和第一层50在第一方向X上存在重叠，并满足L＝0.3d1。最后进行注液、封装，得到电池。
实施例2-4
与实施例1不同之处在于L与d1的关系。
实施例5
与实施例1不同之处在于，第三层70也延长至和第一层50在第一方向X上存在重叠。
对比例
与实施例1不同之处在于从第一方向X观察，第二层60的第一区域61与第一层50不重叠，且L＝1.1d1。
对各实施例和对比例的电池进行跌落测试、滚筒跌落测试和循环测试，对应的测试结果记录于表1和表2中。
其中，跌落测试步骤如下：
1)在25±5℃的环境条件下，将电池在0.2C下充电至充电限制电压；2)将电池放入专用跌落测试夹具内，以机械臂抓取样品，将电池的底面、侧面、顶面为一轮依次从高度为1.8m的位置跌落至大理石板上，共计跌落3轮即9次；3)每一轮跌落后观察电芯是否有破损，漏液，并测量电池的开路电压和内阻(测试仪器为电压电阻测试仪，厂家：东莞市立佳精密仪器有限公司，型号：LNG-SY1-0020-DQ)，若电压小于3.0V即判定为电池失效；若未出现破损和漏液等情况，且开路电压高于3.0V即判定为未失效，继续跌落至电 池失效，然后记录电池失效时已进行的跌落次数。
滚筒跌落测试步骤如下：
1)在25±5℃的环境条件下，将电池在0.2C下充电至充电限制电压；2)将电池放入专用滚筒跌落测试夹具内，以5圈/min的转速从高度为1m的位置跌落500圈(2次跌落为一圈)，每5圈滚筒跌落后观察电池是否有破损，漏液，并测量电池的开路电压和内阻，若电压小于3.0V即判定为电池失效；若未出现破损和漏液等情况，且开路电压高于3.0V即判定为未失效，继续跌落至电池失效，然后记录电池失效时已进行的跌落次数。
循环测试步骤如下：
1)将电池置于25℃恒温箱中，静置30分钟，使电池达到恒温；2)将电池以1C恒流充电至电压为3.65V，然后以3.65V恒压充电至电流为0.05C，接着以1C恒流放电至电压为2.5V，此为一个充放电循环，首次放电的容量为100％；3)反复进行1000次充放电循环，记录电池的放电容量，然后计算电池的容量保持率；4)通过CT图观察电极组件20是否发生变形，然后拆解电池并观察第一极片21的界面情况。
表1
从表1测试结果可知，相较于对比例，实施例1通过设置第一层50的第二边52相较于第一边51更远离电极组件20的边缘，使得第二边52可以避开第一导电板30的弯折处，且第二层60延长至第一区域61和第一层50在第一方向X上存在重叠，因此在跌落测试和滚筒跌落测试中失效时已跌落次数提高，即实施例1的电池可靠性和使用寿命提升。
表2
从表2测试结果可知，相较于实施例2-4，实施例1的L值较小，在跌落测试和滚筒跌落测试中失效时已跌落次数相差不大。然而由于实施例1的L值较小，因此缺口C尺寸较小，注液后位于第一层50和第一壁11之间的电解液不易流经缺口C并充分浸润电极组件20，因此第一极片21发生轻微紫斑，引起容量衰减。实施例5由于将第三层70也延长至和第一层50在第一方向X上存在重叠，第三层70的胶粘层在跌落测试时至少部分会粘接至电极组件20，使得注液后位于第一层50和第一壁11之间的电解液不易流经缺口C并 充分浸润电极组件20，因此第一极片21也发生轻微紫斑，引起容量衰减。
以上所揭露的仅为本申请较佳实施方式而已，当然不能以此来限定本申请，因此依本申请所作的等同变化，仍属本申请所涵盖的范围。

Claims (21)

  1. 一种电化学装置，包括壳体和电极组件，所述壳体包括第一壁和连接所述第一壁的侧壁，所述第一壁和所述侧壁围设形成容纳腔，所述电极组件收容于所述容纳腔内，自所述第一壁至所述电极组件的方向为第一方向，所述电极组件为卷绕结构，且所述电极组件包括第一极片、第二极片以及设于所述第一极片和所述第二极片之间的隔离膜；其中，
    所述电化学装置还包括第一导电板、第一层和第二层，所述第一导电板包括相连接的第一导电区和第二导电区，所述第二导电区相较于所述第一导电区弯折，所述第一导电区连接所述第一极片，所述第二导电区连接所述第一壁，所述第二导电区包括连接于所述第一导电区的第一端部和与所述第一端部相对设置的第二端部，所述第二导电区自所述第一端部沿与所述第一方向垂直的第二方向延伸；
    所述第一层包含绝缘材料，在所述第一方向上，所述第一层设于所述电极组件以及所述第二导电区之间；
    从所述第一方向观察，所述第一层包括沿所述电极组件的边缘弯曲延伸的第一边以及连接于所述第一边的第二边，所述第二边与所述电极组件存在重叠，所述第二边相较于所述第一边更远离所述电极组件的边缘使所述第一层形成缺口；从所述第一方向观察，所述第二端部与所述第一层存在重叠；
    所述第二层包含绝缘材料，所述第二层包括覆盖所述第二导电区的第一区域，所述第一区域包括相连接的第一分区和第二分区，从所述第一方向观察，所述第一分区覆盖所述缺口，所述第二分区与所述第一层存在重叠。
  2. 如权利要求1所述的电化学装置，其中，从所述第一方向观察，所述第一端部位于所述缺口内。
  3. 如权利要求1所述的电化学装置，其中，所述第一层朝向所述第一壁的表面包括第一凹部，所述第一层在所述第一凹部处与所述第二导电区相接。
  4. 如权利要求1所述的电化学装置，其中，所述第二边包括弯曲部。
  5. 如权利要求1所述的电化学装置，其中，定义第三方向垂直于所述第一方向和所述第二方向，所述第二边在所述第三方向上的尺寸为d2，所述第二导电区在所述第三方向上的尺寸为d，d2>d。
  6. 如权利要求1所述的电化学装置，其中，所述第一极片包括第一集流体和设于所述第一集流体表面的第一活性物质层，所述第一集流体包括与所述第一活性物质层相离的第一部分，所述第一导电区连接于所述第一部分。
  7. 如权利要求6所述的电化学装置，其中，在所述第二方向上，所述第一导电区设于所述第一部分朝向所述侧壁的表面。
  8. 如权利要求1所述的电化学装置，其中，所述第一区域在所述第一方向上设于所述第二导电区和所述电极组件之间。
  9. 如权利要求8所述的电化学装置，其中，所述第二层还包括连接所述第一区域的第二区域，所述第二区域覆盖所述第一导电区。
  10. 如权利要求9所述的电化学装置，其中，所述电化学装置还包括包含绝缘材料的第三层，所述第三层包括在所述第一方向上设于所述第二导电区和所述第一壁之间的第三区域，所述第三区域包括相连接的第三分区和第四分区，从所述第一方向观察，所述第三分区覆盖所述缺口，所述第四分区与所述第一层存在重叠。
  11. 如权利要求10所述的电化学装置，其中，所述第三层还包括连接所述第三区域的第四区域，在所述第二方向上，所述第一导电区设于所述第二区域和所述第四区域之间。
  12. 如权利要求1所述的电化学装置，其中，所述第二层包括层叠的胶粘层和基材，所述胶粘层包含所述绝缘材料，所述基材通过所述胶粘层粘接于所述第一导电板。
  13. 如权利要求12所述的电化学装置，其中，所述电化学装置满足以下条件的至少一者：
    所述基材的材质选自聚酰亚胺或聚对苯二甲酸乙二脂的至少一种；
    所述胶粘层的所述绝缘材料选自丁二烯，异戊二烯、苯乙烯、甲基丙烯酸甲酯、甲基丙烯酸丁酯、丙烯酸异辛酯或丙烯酸丁酯的至少一种。
  14. 如权利要求10所述的电化学装置，其中，所述第四分区包括在所述第二方向上背离所述第三分区的第二端，所述第二端和所述侧壁在所述第二方向上的尺寸为d5，所述第一壁的半径为R，d5＜0.4R。
  15. 如权利要求1所述的电化学装置，其中，定义第三方向垂直于所述第一方向和所述第二方向，所述第二边在所述第三方向上的尺寸为d2，所述第一区域在所述第三方向上的尺寸为d3，d2＜d3。
  16. 如权利要求1所述的电化学装置，其中，所述第二边与所述侧壁在所述第二方向上的距离为第一距离L，所述第二分区包括在所述第二方向上背离所述第一分区的第一端，所述第一端和所述侧壁在所述第二方向上的尺寸为d1，0.4d1＜L＜d1。
  17. 如权利要求1所述的电化学装置，其中，从所述第一方向观察，所述第二导电区与所述电极组件的卷绕中心轴存在重叠。
  18. 如权利要求1所述的电化学装置，其中，所述电极组件的卷绕起始端设有空腔，从所述第一方向观察，所述第一层覆盖所述空腔。
  19. 如权利要求1所述的电化学装置，其中，所述壳体还包括连接于所述侧壁且与所述第一壁相对设置的第二壁，所述第二壁上设有与所述第二壁电性绝缘的导电件，所述电极组件还包括电连接于所述第二极片的第二导电板，所述第二导电板连接所述导电件。
  20. 如权利要求1所述的电化学装置，其中，所述电化学装置为扣式电池，从第一方向观察，所述电极组件的边缘大致为圆形。
  21. 一种电子装置，其包括如权利要求1至20中任一项所述的电化学装置。
PCT/CN2023/101367 2023-06-20 2023-06-20 电化学装置及电子装置 Ceased WO2024259583A1 (zh)

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