WO2023173291A1 - 电化学装置和电子装置 - Google Patents

电化学装置和电子装置 Download PDF

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Publication number
WO2023173291A1
WO2023173291A1 PCT/CN2022/080958 CN2022080958W WO2023173291A1 WO 2023173291 A1 WO2023173291 A1 WO 2023173291A1 CN 2022080958 W CN2022080958 W CN 2022080958W WO 2023173291 A1 WO2023173291 A1 WO 2023173291A1
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WIPO (PCT)
Prior art keywords
negative electrode
perforated
area
electrochemical device
tape
Prior art date
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PCT/CN2022/080958
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English (en)
French (fr)
Inventor
胡克文
陈军
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Ningde Amperex Technology Ltd
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Ningde Amperex Technology Ltd
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Filing date
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Application filed by Ningde Amperex Technology Ltd filed Critical Ningde Amperex Technology Ltd
Priority to PCT/CN2022/080958 priority Critical patent/WO2023173291A1/zh
Priority to EP22931330.9A priority patent/EP4496104A4/en
Priority to CN202280006078.7A priority patent/CN116134636B/zh
Publication of WO2023173291A1 publication Critical patent/WO2023173291A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M50/534—Electrode connections inside a battery casing characterised by the material of the leads or tabs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/572—Means for preventing undesired use or discharge
    • H01M50/584—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries
    • H01M50/59—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries characterised by the protection means
    • H01M50/595—Tapes
    • 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
    • H01M50/536—Electrode connections inside a battery casing characterised by the method of fixing the leads to the electrodes, e.g. by welding
    • 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
    • H01M50/54—Connection of several leads or tabs of plate-like electrode stacks, e.g. electrode pole straps or bridges
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • This application relates to the field of electrochemistry, and mainly relates to an electrochemical device and an electronic device.
  • Lithium-ion batteries have the characteristics of large specific energy, high operating voltage, low self-discharge rate, small size, and light weight. They are widely used in various fields such as electrical energy storage, portable electronic devices, and electric vehicles. As the scope of use of lithium-ion batteries continues to expand, the market has put forward higher requirements for lithium-ion batteries, such as faster charging speed and longer service life.
  • lithium ions tend to accumulate on the edges of the tape at the negative electrode tabs, causing lithium precipitation, leading to deterioration of the negative electrode interface, rapid decline in cycle performance and accelerated volume expansion of the lithium-ion battery.
  • Lithium precipitation not only reduces the performance of lithium-ion batteries and greatly shortens their cycle life, but also limits the fast charging capacity of lithium-ion batteries and may cause combustion, explosion and other consequences. In view of this, there is an urgent need to solve the problem of lithium evolution during the lithium-ion battery cycle.
  • the purpose of this application is to provide an electrochemical device and an electronic device to improve the lithium evolution problem of the electrochemical device.
  • the specific technical solutions are as follows:
  • a first aspect of the present application provides an electrochemical device, which includes an electrode assembly, the electrode assembly includes a positive electrode, a negative electrode and a separator, the separator is disposed between the adjacent positive electrode and the negative electrode;
  • the negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.
  • the negative electrode is provided with a negative electrode tab groove that exposes the negative electrode current collector. The negative electrode tab is fixed on the negative electrode electrode.
  • the surface of the negative electrode lug is provided with perforated tape, and the edge of the perforated tape is provided with holes along the length direction, and the perforated tape is The holes are located in the portion of the perforated tape covering the negative electrode active material layer on both sides of the negative electrode tab groove.
  • the inventor of the present application found that by pasting the perforated tape at the groove of the negative electrode tab, and making the holes of the perforated tape located in the negative electrode active material layer on both sides of the negative electrode tab groove, the negative electrode electrode can be prevented from being damaged.
  • the burrs around the ears affect the safety performance of the electrochemical device.
  • by punching holes along the lengthwise edge of the punched tape lithium ions can pass through the holes of the punched tape and be transmitted between the positive and negative electrodes, reducing the risk of lithium ions being punched.
  • the edge of the tape accumulates, thereby dispersing lithium ions around the perforated tape, improving the lithium deposition phenomenon in the negative electrode tab slot, and further improving the lithium deposition problem of the electrochemical device.
  • the positive electrode includes an opposite first surface and a second surface, and the first surface is close to the negative electrode; the perforated tape is also pasted between the first surface and the negative electrode. position corresponding to the negative electrode tab groove.
  • the perforated tape is also pasted on the second surface at a position corresponding to the negative electrode tab groove.
  • the perforated tape goes around the edge of the positive end and is pasted on the second surface at a position corresponding to the negative electrode tab groove.
  • a first perforated area, a second perforated area and a non-perforated area are provided along the width direction of the perforated tape, and the non-perforated area is located at the first Between the perforated area and the second perforated area, the width w 1 of the perforated tape is 6 mm to 30 mm, the width of the first perforated area is w 2 , and the width w 2 of the second perforated area
  • the width w 3 , w 2 and w 3 are each independently selected from 1 mm to 10 mm, the width w 4 of the non-perforated area is 2 mm to 10 mm, the width of the first perforated area or the second perforated area is The ratio of the width of the area to the width of the non-perforated area is 0.5:1 to 1:1.
  • the inventor of the present application found that by controlling the width of the perforated tape to meet the above requirements, and cooperatively controlling the widths of the first perforated area, the second perforated area and the non-perforated area within the above range, the electrical performance can be further improved. Lithium evolution problem in chemical devices.
  • the holes of the punched tape meet at least one of the following characteristics: (1) The distance b between the holes is 0 mm to 2 mm, and the minimum diameter c of the circumscribed circle of the outline of the holes is 0.1 mm to 3mm; (2) The total area of the holes in the first punching area accounts for 20% to 80% of the area of the first punching area, and the total area of the holes in the second punching area accounts for 20% to 80% of the area of the second punching area. The area ratio of the hole area is 20% to 80%; (3) the shape of the hole is at least one of circular, elliptical, and polygonal.
  • the inventor of the present application has discovered through research that by controlling the holes of the perforated tape to satisfy one, two, or a combination of more than two of the above characteristics, the problem of lithium deposition in the electrochemical device can be improved.
  • the perforated adhesive paper includes an adhesive layer and a base material layer
  • the adhesive layer includes polyolefin and/or modified polyolefin, as well as elastomers, fillers and antioxidants, based on The total mass of the glue layer, the mass percentage of the polyolefin and/or modified polyolefin is 45% to 85%, the mass percentage of the elastomer is 10% to 35%, and the filler
  • the mass percentage content of the antioxidant is 2% to 10%, and the mass percentage content of the antioxidant is 2% to 10%.
  • the inventor of the present application has discovered through research that by cooperatively controlling the mass percentage of each component in the adhesive layer within the above range, it is beneficial to improve the electrolyte resistance and adhesive force of the perforated adhesive paper, reduce the swelling degree, and thereby improve Safety performance of electrochemical devices, extending the service life of electrochemical devices and controlling costs.
  • the adhesive layer meets at least one of the following characteristics: (1) the polyolefin includes polyethylene and/or polypropylene, and the modified polyolefin includes maleic anhydride modified polyethylene and/or maleic anhydride modified polypropylene, the weight average molecular weights of the polyolefin and the modified polyolefin are each independently selected from 30,000 to 200,000; (2) the elastomer includes styrene-ethylene-butan At least one of ethylene-styrene block copolymer, polyurethane, polyamide, polybutadiene or polyisobutylene; (3) the filler includes at least one of titanium dioxide, talc, white carbon black or calcium carbonatekind; (4) The antioxidant includes at least one of diphenylamine, trimethyl phosphite, triethyl phosphite or distearyl thiodipropionate.
  • the inventor of the present application has discovered through research that by controlling the adhesive layer of the perforated tape to meet one, two or a combination of more than two of the above conditions, the lithium deposition problem of the electrochemical device can be further improved and the performance of the electrochemical device can be improved. Safety performance.
  • the substrate layer includes at least one of polyethylene terephthalate, polyimide or polypropylene.
  • the inventor of the present application has discovered through research that by selecting the above-mentioned materials as the base material layer, it is beneficial to improve the electrolyte resistance of the perforated tape, thereby improving the lithium precipitation problem of the electrochemical device and improving the safety performance of the electrochemical device.
  • the thickness of the glue layer is 4 ⁇ m to 20 ⁇ m
  • the thickness of the base material layer is 4 ⁇ m to 30 ⁇ m.
  • the adhesive force of the perforated tape after being soaked in 85°C electrolyte for 4 hours is 0.2N/mm to 0.5N/mm.
  • the inventor of the present application has found through research that when When the adhesive force of the porous adhesive paper is within the above range, it is beneficial to improve the lithium precipitation problem of the electrochemical device and improve the safety performance of the electrochemical device.
  • the thickness A of the perforated tape soaked in the electrolyte solution at 85°C for 24 hours and the thickness B without being soaked in the electrolyte solution satisfy: 0 ⁇ m ⁇ A-B ⁇ 2 ⁇ m, that is, the application provides
  • the perforated tape has a low swelling degree, which is beneficial to improving the safety performance of electrochemical devices and lithium precipitation problems.
  • the maximum glue overflow width on one side of the perforated tape is 0 mm to 1 mm. That is, the perforated tape provided by the present application has good thermal stability and is conducive to improving electrochemical devices. safety performance.
  • the present application provides an electrochemical device and an electronic device.
  • the electrochemical device includes an electrode assembly.
  • the electrode assembly includes a positive electrode, a negative electrode and a separator.
  • the negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.
  • the negative electrode There is a negative electrode tab groove exposing the negative electrode current collector, and the negative electrode tab is fixed in the negative electrode tab groove and electrically connected to the negative electrode current collector; wherein, the surface of the negative electrode tab is provided with a perforated tape, and the perforated tape is Holes are provided along the edge of the length direction, and the holes of the perforated tape are located in the portion of the perforated tape that covers the negative active material layer on both sides of the negative electrode tab groove.
  • the electronic device of the present application includes the electrochemical device of the present application. Therefore, the electronic device of the present application also has good safety performance.
  • Figure 1 is a schematic cross-sectional structural diagram along the thickness direction of an electrode assembly according to some embodiments of the present application
  • Figure 2 is a partial enlarged view of point A in Figure 1;
  • Figure 3 is a schematic structural diagram of the negative electrode perforated adhesive tape in other embodiments of the present application.
  • Figure 4 is a schematic structural diagram of perforated tape according to some embodiments of the present application.
  • Figure 5 is a schematic cross-sectional structural diagram along the thickness direction of an electrode assembly according to some embodiments of the present application.
  • Figure 6 is a partial enlarged view of B in Figure 5;
  • Figure 7 is a schematic cross-sectional structural diagram along the thickness direction of an electrochemical device according to some embodiments of the present application.
  • Figure 8 is a partial enlarged view of C in Figure 7;
  • Figure 9 is a partial cross-sectional structural diagram along the length direction of an electrochemical device according to some embodiments of the present application.
  • Figure 10 is a partial cross-sectional structural diagram along the length direction of an electrochemical device according to other embodiments of the present application.
  • Negative electrode 11. Negative electrode tab; 12. Negative electrode current collector; 13. Negative electrode active material layer; 14. Negative electrode tab groove; 20. Separator; 30. Positive electrode; 31. Positive electrode tab; 32 .Positive current collector; 33. Positive active material layer; 40. Perforated tape; 41. Hole; 42. First perforated area; 43. Second perforated area; 44. Non-perforated area; 50. Green glue .
  • a lithium ion battery is used as an example of an electrochemical device to explain the present application, but the electrochemical device of the present application is not limited to lithium ion batteries.
  • the present application provides an electrochemical device and an electronic device.
  • a first aspect of the present application provides an electrochemical device, which includes an electrode assembly.
  • the electrode assembly includes a positive electrode, a negative electrode and a separator.
  • the separator is disposed between adjacent positive electrodes and negative electrodes;
  • the negative electrode includes a negative electrode current collector and is disposed on the negative electrode collector.
  • the negative electrode active material layer on at least one surface of the fluid the negative electrode is provided with a negative electrode tab groove exposing the negative electrode current collector, the negative electrode tab is fixed in the negative electrode tab groove and is electrically connected to the negative electrode current collector; wherein, the surface of the negative electrode tab A perforated tape is provided, and holes are provided along the edge of the perforated tape along the length direction. The holes of the perforated tape are located in the portion of the perforated tape that covers the negative electrode active material layer on both sides of the negative electrode tab groove.
  • the electrode assembly includes a negative electrode 10, a positive electrode 30, a separator 20 between the positive electrode 30 and the negative electrode 10, perforated tape 40, and green glue 50.
  • the positive electrode 30 includes a positive electrode tab 31, a positive electrode current collector 32, and a positive electrode active material layer 33.
  • the negative electrode 10 includes a negative electrode tab 11 , a negative electrode current collector 12 , a negative electrode active material layer 13 and a negative electrode tab groove 14 .
  • the perforated tape 40 is pasted on the area where the negative electrode tab 11 is connected to the negative electrode 10, and covers the negative electrode tab groove 14. It can be understood that the area of the perforated tape 40 is larger than The area of the negative electrode tab groove 14 , and the holes 41 of the perforated tape 40 are located in the portion of the perforated tape 40 covering the negative electrode active material layer 13 on both sides of the negative tab groove 14 .
  • the parts of the negative active material layer 13 on both sides of the negative tab groove 14 refer to the partial surface of the negative active material layer 13 on both sides of the negative tab groove 14, that is, along the thickness direction of the electrode assembly (z direction),
  • the orthographic projection of the hole 41 of the perforated tape 40 on the negative electrode 10 does not overlap at all with the orthographic projection of the negative electrode tab groove 14 on the negative electrode 10 , as shown in FIG. 3 .
  • a plane rectangular coordinate system is established with the length direction of the perforated tape as the y' direction and the width direction of the perforated tape as the x' direction.
  • a hole 41 penetrating the punched tape 40 is provided at an edge of the punched tape 40 in the longitudinal direction (y' direction).
  • the edges in the length direction (y' direction) of the punched tape 40 refer to the two opposite edges along the width direction (x' direction) of the punched tape. It can be understood that the holes of the punching tape can be arranged evenly or unevenly, as long as the purpose of the present application can be achieved.
  • the inventor of the present application found that by pasting perforated tape on the groove of the negative electrode tab, and positioning the holes of the perforated tape on both sides of the groove of the negative electrode tab, it is possible to avoid burrs around the negative electrode tab.
  • lithium ions can pass through the holes of the punched tape and be transported between the positive electrode and the negative electrode (arrow in Figure 2) as shown, is the transmission direction of lithium ions), reducing the accumulation of lithium ions at the edge of the perforated tape, thereby dispersing lithium ions around the perforated tape, improving the lithium precipitation phenomenon in the negative electrode tab slot, and further improving the precipitation of the electrochemical device. Lithium issue.
  • the positive electrode tab is a metal conductor drawn from the positive electrode
  • the negative electrode tab is a metal conductor drawn from the negative electrode.
  • the positive electrode tab and the negative electrode tab are used to connect other parts of the electrochemical device in series or in parallel.
  • This application has no special restrictions on the materials of the positive electrode tab and the negative electrode tab, as long as the purpose of the application can be achieved.
  • the materials of the positive electrode tab and the negative electrode tab known in the art can be used.
  • This application has no special limitation on the formation method of the negative electrode tab groove. Formation methods known in the art can be used, as long as the purpose of this application can be achieved. For example, it can be by using laser cleaning in the corresponding negative electrode area, or by First, paste the foam adhesive paper on the negative electrode current collector, apply the negative electrode active material layer and dry it, then peel off the foam adhesive paper to obtain the negative electrode tab groove.
  • the positive electrode includes an opposite first surface and a second surface, the first surface is close to the negative electrode; the perforated tape is also pasted on the first surface at a position corresponding to the groove of the negative electrode tab.
  • the perforated tape 40 is respectively pasted on the surface of the negative electrode tab groove 14 and the surface of the positive active material layer 33 on the first surface of the positive electrode 30 , and the pasting position is in line with the negative electrode.
  • the position of pole lug groove 14 corresponds.
  • the inventor of the present application found that by pasting the perforated tape on the first surface of the above-mentioned positive electrode, the lithium around the perforated tape can be dispersed compared to the prior art of using non-perforated tape to stick to the corresponding position. ions to further improve the lithium evolution problem of electrochemical devices.
  • the first surface and the second surface of the positive electrode are two opposite surfaces along the thickness direction of the positive electrode, where the thickness direction of the positive electrode is the same as the thickness direction (z direction) of the electrode assembly.
  • the end of the positive electrode refers to the direction along the extension direction of the negative electrode tab, the positive electrode is along its own length direction and close to the side of the negative electrode tab; the end of the negative electrode refers to the direction along the extension direction of the negative electrode tab, and the negative electrode is along its own length direction and The side closest to the negative pole.
  • the length direction of the positive electrode itself and the length direction of the negative electrode itself are the same as the width direction (x direction) of the electrode assembly.
  • the perforated tape can also be pasted on the second surface at a position corresponding to the groove of the negative electrode tab.
  • the perforated tape 40 is pasted on the surface of the negative electrode tab groove 14
  • the perforated tape 40 is also pasted on the first surface and the second surface of the positive electrode 30 in contact with the negative electrode. The position corresponding to the tab groove 14.
  • the inventor of the present application has discovered through research that by pasting perforated tapes on the above-mentioned first surface and second surface respectively at positions corresponding to the grooves of the negative electrode tabs, the problem of lithium deposition caused by obstruction of lithium ion transmission can be improved, and The problem of lithium ions diffusing from the positive terminal to the adjacent negative terminal can improve the lithium deposition at the negative terminal and further improve the lithium deposition problem of the electrochemical device.
  • the perforated tape goes around the edge of the positive end and is pasted on the second surface at a position corresponding to the groove of the negative electrode tab.
  • the perforated tape 40 is pasted on the surface of the negative electrode tab groove 14 , and the perforated tape 40 is also pasted on the first surface and the second surface of the positive electrode 30 and the negative electrode tab groove 14 .
  • the perforated tape 40 goes around the end of the positive electrode 30 to wrap the end of the positive electrode 30 .
  • a first punching area 42 , a second punching area 43 and The non-perforated area 44 is located between the first perforated area 42 and the second perforated area 43 .
  • the width w 1 of the punched tape 40 is 6 mm to 30 mm.
  • w 1 can be 6 mm, 12 mm, 18 mm, 24 mm, 30 mm or any range in between.
  • the width of the first perforated area 42 is w 2 and the width of the second perforated area 43 is w 3 .
  • w 2 and w 3 are each independently selected from 1 mm to 10 mm.
  • w 2 can be 1 mm, 2.5 mm, 5 mm, 7.5mm, 10mm or any range in between
  • w 3 can be 1mm, 2.5mm, 5mm, 7.5mm, 10mm or any range in between
  • the width w 4 of the non-perforated area 44 is 2 mm to 10 mm.
  • w 4 may be 2 mm, 4 mm, 6 mm, 8 mm, 10 mm or any range in between.
  • the ratio of the width of the first perforated area 42 or the width of the second perforated area 43 to the width of the non-perforated area 44 is 0.5:1 to 1:1.
  • w 2 :w 4 can be 0.5:1, 0.6: 1, 0.7:1, 0.8:1, 0.9:1, 1:1 or any range in between
  • w 3 :w 4 can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1 , 1:1 or any range in between.
  • the applicant found that by controlling the width of the perforated tape and cooperatively controlling the width of the first perforated area, the second perforated area and the non-perforated area within the above range, lithium ions can be better dispersed. To improve the accumulation of lithium ions around the perforated tape, thereby further improving the lithium precipitation problem of the electrochemical device.
  • the widths of the first perforated area and the second perforated area may be equal or unequal.
  • the holes of the perforated tape meet at least one of the following characteristics:
  • the distance b between holes is 0mm to 2mm, and the minimum diameter c of the circumscribed circle of the hole outline is 0.1mm to 3mm.
  • the distance between holes 41 is the distance between the outlines of two adjacent holes 41 the minimum straight-line distance.
  • b can be 0mm, 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm or any range in between
  • c can be 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm or any range in between. Any range.
  • the inventor of the present application has discovered through research that by making the spacing and diameter of the holes meet the above range, the holes in the perforated tape can be dispersed more evenly, so that lithium ions can be better transported between the positive electrode and the negative electrode, thereby improving Lithium evolution problem in electrochemical devices.
  • the total area of the holes in the first perforation area accounts for 20% to 80% of the area of the first perforation area, preferably 30% to 70%; the total area of the holes in the second perforation area
  • the proportion of the area of the second perforated area is 20% to 80%, preferably 30% to 70%.
  • the ratio of the total area of the holes in the first perforation area to the area of the first perforation area can be 20%, 30%, 40%, 50%, 60%, 70%, 80%, or anything in between. range
  • the ratio of the total area of the holes in the second perforation area to the area of the second perforation area can be 20%, 30%, 40%, 50%, 60%, 70%, 80% or any value in between. scope.
  • the inventor of the present application found through research that the total area of the holes in the first perforation area accounts for the proportion of the area of the first perforation area, or the total area of the holes in the second perforation area accounts for the proportion of the second perforation area.
  • the area ratio is too small (for example, less than 20%), lithium ions cannot be effectively dispersed through the holes of the perforated tape, and are easy to accumulate around the perforated tape, which will not significantly improve the problem of lithium deposition in the electrochemical device; when the first The ratio of the total area of the holes in the perforation area to the area of the first perforation area, or when the ratio of the total area of the holes in the second perforation area to the area of the second perforation area is too large (for example, greater than 80 %), the adhesive force of the perforated tape decreases and it cannot effectively bind the negative electrode tab, which will affect the safety performance of the electrochemical device. Therefore, by controlling the areas of the holes in the first perforated area and the second perforated area to be within the above range, the lithium deposition problem of the electrochemical device can be improved, and the electrochemical device can have good safety performance.
  • the shape of the hole is at least one of a circle, an ellipse, and a polygon.
  • the polygon can include but is not limited to a triangle, a quadrilateral, a pentagon, etc.
  • the shape of the hole is more conducive to the preparation of punched tape. .
  • the inventor of the present application has discovered through research that by controlling the holes of the perforated tape to satisfy one, two, or a combination of more than two of the above characteristics, the problem of lithium deposition in the electrochemical device can be improved.
  • the perforated adhesive paper includes an adhesive layer and a base material layer, and the adhesive layer includes polyolefin and/or modified polyolefin, as well as elastomers, fillers and antioxidants.
  • the mass percentage of polyolefin and/or modified polyolefin is 45% to 85%.
  • the mass percentage of polyolefin and/or modified polyolefin can be 45%, 50%. %, 60%, 70%, 80%, 85% or any range in between.
  • the mass percentage of polyolefin and/or modified polyolefin refers to the mass percentage of polyolefin; when only modified polyolefin is included but no polyolefin is included.
  • the mass percentage of olefins, polyolefins and/or modified polyolefins refers to the mass percentage of modified polyolefins; when it includes both polyolefins and modified polyolefins, the mass of polyolefins and/or modified polyolefins
  • the percentage content refers to the sum of the mass percentage content of polyolefin and modified polyolefin.
  • the mass percentage of the elastomer is 10% to 35%.
  • the mass percentage of the elastomer can be 10%, 15%, 20%, 25%, 30%, 35% or any range therebetween.
  • the mass percentage of the filler is 2% to 10%.
  • the mass percentage of the filler can be 2%, 4%, 6%, 8%, 10% or any range therebetween.
  • the mass percentage of the antioxidant is 2% to 10%.
  • the mass percentage of the antioxidant can be 2%, 4%, 6%, 8%, 10% or any range therebetween.
  • the inventor of the present application has discovered through research that when the mass percentage of polyolefin and/or modified polyolefin is too low (for example, less than 45%), it will affect the electrolyte resistance, adhesion and strength of the perforated tape. Swelling properties. When the mass percentage of polyolefin and/or modified polyolefin is too high (for example, higher than 85%), the flexibility of the adhesive layer will become poor and the polyolefin and/or modified polyolefin will be wasted, resulting in electrochemical The cost of the device increases.
  • the glue layer meets at least one of the following characteristics:
  • Polyolefins include polyethylene and/or polypropylene, and modified polyolefins include maleic anhydride-modified polyethylene and/or maleic anhydride-modified polypropylene.
  • the weight average molecular weights of polyolefins and modified polyolefins are independent of each other. is selected from 30,000 to 200,000.
  • the weight average molecular weight of the polyolefin can be 30,000, 55,000, 100,000, 155,000, 200,000, or any range therebetween
  • the weight average molecular weight of the modified polyolefin can be 30,000, 55,000, 100,000, 155,000, 200,000 or any range in between.
  • the inventor of the present application has discovered through research that by regulating the weight average molecular weight of polyolefins and modified polyolefins within the above range, it is beneficial to improve the adhesive force of the perforated tape, so that the perforated tape can effectively bind the tabs, and at the same time Reduce the number of lithium ions precipitated from under the perforated tape after the perforated tape is soaked in the electrolyte for a long time, further improve the lithium precipitation problem of the electrochemical device, and improve the safety performance of the electrochemical device.
  • the elastomer includes at least one of styrene-ethylene-butylene-styrene block copolymer, polyurethane, polyamide, polybutadiene or polyisobutylene, where the elastomer refers to one that deforms under weak stress
  • the polymer material can quickly return to its original state and size after stress relaxation.
  • the inventor of the present application has discovered through research that the adhesive force of the perforated tape can be further improved by adding the above-mentioned elastomer in the adhesive layer. When the adhesive force of the perforated tape is too low, it cannot effectively bind the negative electrode tab.
  • lithium ions can easily precipitate from the bottom of the perforated tape, causing lithium to precipitate in the electrochemical device.
  • the lithium precipitation problem of the electrochemical device can be improved and the safety performance of the electrochemical device can be improved.
  • the filler includes at least one of titanium dioxide, talc, white carbon black or calcium carbonate.
  • the inventor of the present application has found through research that by selecting the above filler, it is beneficial to improve the electrolyte resistance of the perforated tape. When the perforated tape is soaked in the electrolyte for a long time, it can slow down the precipitation of lithium ions under the perforated tape, further improve the lithium precipitation problem of the electrochemical device, and improve the safety performance of the electrochemical device.
  • the antioxidant includes at least one of diphenylamine, trimethyl phosphite, triethyl phosphite or distearyl thiodipropionate.
  • the inventor of the present application has found through research that by selecting the above antioxidant
  • the oxygen agent can improve the electrolyte resistance of the perforated tape. When the perforated tape is soaked in the electrolyte for a long time, it can slow down the precipitation of lithium ions under the perforated tape, further improving the lithium precipitation problem of the electrochemical device. Improve the safety performance of electrochemical devices.
  • the inventor of the present application has discovered through research that by controlling the adhesive layer of the perforated tape to meet one, two, or a combination of more than two of the above conditions, the safety performance of the electrochemical device and the problem of lithium deposition can be further improved.
  • the substrate layer includes at least one of polyethylene terephthalate, polyimide or polypropylene.
  • the inventor of the present application has discovered through research that by selecting the above-mentioned materials as the base material layer, it is beneficial to improve the electrolyte resistance of the perforated tape. When the perforated tape is soaked in the electrolyte for a long time, it can slow down the movement of the perforated tape underneath. The precipitation of lithium ions further improves the lithium precipitation problem of electrochemical devices and improves the safety performance of electrochemical devices.
  • the thickness of the glue layer is 4 ⁇ m to 20 ⁇ m.
  • the thickness of the glue layer can be 4 ⁇ m, 5 ⁇ m, 8 ⁇ m, 10 ⁇ m, 12 ⁇ m, 15 ⁇ m, 18 ⁇ m, 20 ⁇ m, or any range in between;
  • the thickness of the material layer is 4 ⁇ m to 30 ⁇ m.
  • the thickness of the base material layer may be 4 ⁇ m, 5 ⁇ m, 10 ⁇ m, 12 ⁇ m, 20 ⁇ m, 25 ⁇ m, 30 ⁇ m or any range in between.
  • the inventor of the present application has discovered through research that when the thickness of the adhesive layer is too small (for example, less than 4 ⁇ m), performance changes are more likely to occur when soaked in electrolyte, affecting the adhesive force of the perforated adhesive paper, thereby affecting the safety performance of the electrochemical device. Within a certain range, the adhesive force of the adhesive paper tends to increase as the thickness of the adhesive layer increases. However, when the thickness of the adhesive layer is too large (for example, greater than 20 ⁇ m), the adhesive force of the adhesive layer tends to remain unchanged, but Will affect the energy density of electrochemical devices. When the thickness of the base material layer is too small (for example, less than 4 ⁇ m), the supporting effect on the adhesive layer is weak, resulting in poor fixation effect on the negative electrode tab.
  • the thickness of the base material layer is too large (for example, greater than 30 ⁇ m), the effect is comparable to the embodiments within the scope of the present application, but will affect the energy density of the electrochemical device.
  • the thickness of the adhesive layer and the thickness of the substrate layer in the perforated tape can be within the above range, the energy density of the electrochemical device can be maintained and the safety performance of the electrochemical device can be improved.
  • the adhesive force of the perforated tape after being soaked in 85°C electrolyte for 4 hours is 0.2N/mm to 0.5N/mm, that is, the perforated tape of the present application has good adhesion.
  • the bonding force can effectively bind the tabs, which is beneficial to improving the safety performance of the electrochemical device.
  • the bonding force of the perforated tape is too low (less than 0.2N/mm)
  • lithium ions are easily immersed in the electrolyte for a long time. It precipitates from the bottom of the perforated tape, causing lithium to precipitate in the electrochemical device.
  • the adhesive force of perforated tape after soaking in 85°C electrolyte for 4 hours can be 0.2N/mm, 0.3N/mm, 0.4N/mm, 0.5N/mm, or any range in between.
  • the adhesive force test after the perforated tape is soaked in 85°C electrolyte for 4 hours is to first heat press the perforated tape, then put it into the electrolyte for soaking, and finally test its adhesion.
  • the thickness A of the perforated adhesive paper soaked in the electrolyte solution at 85°C for 24 hours and the thickness B without being soaked in the electrolyte satisfy: 0 ⁇ m ⁇ A-B ⁇ 2 ⁇ m, that is, the perforated adhesive paper provided in this application
  • the low swelling degree of the paper is beneficial to improving the safety performance of the electrochemical device.
  • the swelling of the perforated tape is too high (A-B is greater than 2 ⁇ m)
  • lithium ion transmission is blocked, affecting the rate performance of the electrochemical device.
  • the value of A-B can be 0.01 ⁇ m, 0.5 ⁇ m, 1 ⁇ m, 1.5 ⁇ m, 2 ⁇ m, or any range in between.
  • the maximum glue overflow width of one side of the perforated tape is 0 mm to 1 mm. That is, the perforated tape provided by the present application has good thermal stability and can better bind the negative electrode. ears to improve the safety performance of electrochemical devices.
  • the maximum glue overflow width on one side of the perforated tape can be 0mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm or anything in between. scope.
  • the maximum glue overflow width of a single side of the perforated tape refers to the maximum width of the perforated tape after hot pressing at a temperature of 85°C and a pressure of 1 MPa for 1 hour. Process one-half the difference in width of the punched tape.
  • the perforated adhesive paper may also include release paper, and the release paper is disposed on the surface of the adhesive layer facing away from the base material layer.
  • the setting of the release paper in the punched tape is to prevent the surface of the adhesive layer from contacting the non-attached target surface or itself, so as to avoid the adhesive layer from sticking to the non-attached target surface or itself during the use of the punched tape.
  • Sticky those skilled in the art can select any suitable release paper material or size in the art according to actual needs.
  • the release paper can be disposed on one side on any exposed surface of the adhesive layer, for example, but not limited to, the surface of the adhesive layer facing away from the base material layer or the surface of the side of the adhesive layer.
  • the release paper is removed before the adhesive layer in the perforated adhesive paper is pasted to the target surface.
  • the release paper includes a single-sided silicon release film or a double-sided silicon release film.
  • this application has no special restrictions on the preparation method of the perforated adhesive paper, as long as the purpose of this application can be achieved.
  • this application can adopt the following method for preparing perforated adhesive paper, which includes the following steps: mixing the raw materials of the adhesive layer according to a certain proportion to obtain the adhesive layer slurry, and then coating the adhesive layer slurry on the base material layer, and drying Finally, the adhesive paper is obtained, and holes are further punched on the edge of the adhesive paper in the length direction.
  • This application does not specifically limit the method of drilling, as long as the purpose of this application can be achieved, for example, it can be through laser drilling or mechanical drilling.
  • the base material layer can be treated with a non-silicon release agent first and then corona treatment is performed on the surface.
  • the drying temperature can be 60°C to 120°C.
  • the positive electrode in this application is not particularly limited as long as the purpose of this application can be achieved.
  • the positive electrode usually includes a positive electrode current collector and a positive electrode active material layer.
  • the positive electrode current collector is not particularly limited as long as it can achieve the purpose of this application.
  • it may include but is not limited to aluminum foil, aluminum alloy foil or composite current collector.
  • the thickness of the positive electrode current collector there is no particular restriction on the thickness of the positive electrode current collector, as long as the purpose of this application can be achieved, for example, the thickness is 8 ⁇ m to 12 ⁇ m.
  • the positive active material layer may be provided on one surface in the thickness direction of the positive current collector, or may be provided on both surfaces in the thickness direction of the positive current collector.
  • the "surface” here can be the entire area of the positive electrode current collector, or it can be a partial area of the positive electrode current collector. There is no particular limitation in this application, as long as the purpose of this application can be achieved.
  • the positive active material layer includes a positive active material.
  • the positive active material is not particularly limited as long as it can achieve the purpose of this application.
  • it may include at least one of a composite oxide of lithium and a transition metal element.
  • This application does not have special restrictions on the above-mentioned transition metal elements, as long as the purpose of this application can be achieved.
  • it may include at least one of nickel, manganese, cobalt or iron.
  • the positive active material may include lithium nickel cobalt manganate (811, 622, 523, 111), lithium nickel cobalt aluminate, lithium iron phosphate, lithium-rich manganese-based materials, lithium cobalt oxide, lithium manganate, lithium iron phosphate Or at least one of lithium titanate.
  • the positive active material layer may also include a conductive agent.
  • a conductive agent may include but is not limited to conductive carbon black (Super P), carbon nanoparticles At least one of tubes (CNTs), carbon fiber, flake graphite, Ketjen black, graphene, metallic materials or conductive polymers.
  • the above-mentioned carbon nanotubes may include, but are not limited to, single-walled carbon nanotubes and/or multi-walled carbon nanotubes.
  • the above-mentioned carbon fibers may include, but are not limited to, vapor grown carbon fibers (VGCF) and/or nanocarbon fibers.
  • the above-mentioned metal material may include but is not limited to metal powder and/or metal fiber.
  • the metal may include but is not limited to at least one of copper, nickel, aluminum or silver.
  • the above-mentioned conductive polymer may include, but is not limited to, at least one of polyphenylene derivatives, polyaniline, polythiophene, polyacetylene or polypyrrole.
  • the positive active material layer may also include a binder.
  • the binder is not particularly limited in this application as long as it can achieve the purpose of this application.
  • it may include but is not limited to polyacrylic acid, sodium polyacrylate, polyacrylate, Potassium acrylate, lithium polyacrylate, polyimide, polyvinyl alcohol, carboxymethylcellulose, sodium carboxymethylcellulose, lithium carboxymethylcellulose, polyimide, polyamideimide, styrene-butadiene rubber or at least one of polyvinylidene fluoride.
  • the positive electrode may further include a conductive layer located between the positive electrode current collector and the positive electrode active material layer.
  • the composition of the conductive layer is not particularly limited in this application. It may be a conductive layer commonly used in the art, which may include, but is not limited to, the above-mentioned conductive agent and the above-mentioned adhesive.
  • the negative active material layer may be disposed on one surface in the thickness direction of the negative electrode current collector, or may be disposed on both surfaces in the thickness direction of the negative electrode current collector.
  • the "surface” here can be the entire area of the negative electrode current collector, or it can be a partial area of the negative electrode current collector. There is no particular limitation in this application, as long as the purpose of this application can be achieved.
  • the negative electrode current collector in this application is not particularly limited as long as it can achieve the purpose of this application.
  • it can include but is not limited to copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam or composite Current collector etc.
  • the thickness of the current collector of the negative electrode there is no particular limitation on the thickness of the current collector of the negative electrode, as long as the purpose of this application can be achieved, for example, the thickness is 4 ⁇ m to 12 ⁇ m.
  • the negative active material layer includes a negative active material.
  • the negative active material is not particularly limited as long as it can achieve the purpose of this application.
  • it can include but is not limited to natural graphite, artificial graphite, mesophase microcarbon spheres, Hard carbon, soft carbon, silicon, silicon-carbon composite, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO 2 , spinel structure lithiated TiO 2 -Li 4 Ti 5 O 12 or At least one kind of Li-Al alloy.
  • the negative active material layer may also include a conductive agent.
  • the conductive agent is not particularly limited in this application, as long as it can achieve the purpose of this application.
  • it may include but is not limited to at least one of the above conductive agents.
  • the negative active material layer may also include a binder.
  • the binder is not particularly limited in this application, as long as it can achieve the purpose of this application.
  • it may include but is not limited to at least one of the above-mentioned binders. kind.
  • the negative electrode may further include a conductive layer located between the negative electrode current collector and the negative electrode active material layer.
  • a conductive layer located between the negative electrode current collector and the negative electrode active material layer.
  • This application has no particular limitation on the composition of the conductive layer. It can be a conductive layer commonly used in this field.
  • the conductive layer can include but is not limited to the above-mentioned conductive agent and the above-mentioned adhesive.
  • the electrochemical device of this application also includes a separator.
  • This application has no special restrictions on the separator, as long as it can achieve the purpose of this application.
  • it can include but is not limited to polyethylene (PE), polypropylene (PP), polytetrafluoroethylene.
  • Mainly polyolefin (PO) separators polyester films (such as polyethylene terephthalate (PET) films), cellulose films, polyimide films (PI), polyamide films (PA), At least one of spandex, aramid film, woven film, non-woven fabric, microporous film, composite film, separator paper, rolled film or spun film, etc.
  • the separator of the present application may have a porous structure, and the size of the pore diameter is not particularly limited as long as the purpose of the present application can be achieved.
  • the size of the pore diameter may be 0.01 ⁇ m to 1 ⁇ m.
  • the thickness of the separator is not particularly limited as long as the purpose of this application can be achieved.
  • the thickness can be 5 ⁇ m to 500 ⁇ m.
  • the separator may include a separator substrate layer and a surface treatment layer.
  • the separator base material layer can be a non-woven fabric, film or composite film with a porous structure.
  • the material of the separator base material layer can include but is not limited to polyethylene, polypropylene, polyethylene terephthalate or polyimide. At least one of the others.
  • a polypropylene porous film, a polyethylene porous film, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, or a polypropylene-polyethylene-polypropylene porous composite film may be used.
  • a surface treatment layer is provided on at least one surface of the separator base material layer.
  • the surface treatment layer may be a polymer layer or an inorganic substance layer, or may be a layer formed by mixing a polymer and an inorganic substance.
  • the polymer layer contains a polymer, and the polymer material may include but is not limited to polypropylene, polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, At least one of polyvinylidene fluoride or polyvinylidene fluoride-hexafluoropropylene.
  • the inorganic layer may include, but is not limited to, inorganic particles and binders. This application has no particular limitation on inorganic particles.
  • it may include, but is not limited to, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, At least one of ceria, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttria, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide or barium sulfate.
  • This application has no particular limitation on the binder in the inorganic layer.
  • it may include but is not limited to polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, and polyacrylic acid. , at least one of polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene or polyhexafluoropropylene.
  • the electrochemical device of the present application is not particularly limited and may include any device that undergoes electrochemical reactions.
  • the electrochemical device may include, but is not limited to, a lithium metal secondary battery, a lithium ion secondary battery (lithium ion battery), a lithium polymer secondary battery, a lithium ion polymer secondary battery, and the like.
  • the preparation process of an electrochemical device is well known to those skilled in the art and is not particularly limited in this application.
  • it may include but is not limited to the following steps: stacking the positive electrode, separator and negative electrode in order, and winding them as needed; Folding and other operations are performed to obtain the electrode assembly of the rolled structure, the electrode assembly is put into the packaging bag, the electrolyte is injected into the packaging bag and sealed to obtain an electrochemical device; or, the positive electrode, separator and negative electrode are stacked in order, and then taped together
  • the four corners of the entire laminated structure are fixed to obtain an electrode assembly of the laminated structure.
  • the electrode assembly is placed in a packaging bag, and the electrolyte is injected into the packaging bag and sealed to obtain an electrochemical device.
  • overcurrent prevention components, guide plates, etc. can also be placed in the packaging bag as needed to prevent pressure rise inside the electrochemical device and overcharge and discharge.
  • a second aspect of the present application provides an electronic device, which includes the electrochemical device provided by the first aspect of the present application.
  • the electronic device of the present application is not particularly limited and may be used in any electronic device known in the art.
  • electronic devices may include, but are not limited to, laptop computers, pen computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headsets, video recorders, LCD TV, portable cleaner, portable CD player, mini CD, transceiver, electronic notepad, calculator, memory card, portable recorder, radio, backup power supply, motor, automobile, motorcycle, power-assisted bicycle, bicycle, lighting equipment , toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.
  • Lithium evolution test of lithium-ion battery at 10°C At 10°C, let the lithium-ion battery stand for 5 minutes, charge it to 4.25V with a constant current of 1.5C, and then charge it to 4.48V with a constant current of 1.2C V, then charge at a constant voltage of 4.48V to 0.02C; let it stand for 5 minutes, discharge to 3.4V with a constant current of 1C, and then discharge to 3.0V with a constant current of 0.2C. Repeat the above steps 9 times and let it sit for 5 minutes. Then charge it with a constant current of 1C to 4.48V, then charge it with a constant voltage of 4.48V to 0.02C. Finally, let it stand for 5 minutes. Disassemble and observe the groove of the negative electrode tab and the end of the negative electrode. The degree of lithium precipitation.
  • Lithium evolution test of lithium-ion battery at 45°C At 45°C, let the lithium-ion battery stand for 5 minutes, charge it to 4.25V with a constant current of 1.5C, and then charge it to 4.48V with a constant current of 1.2C V, then charge with a constant voltage of 4.48V to 0.02C, and let it stand for 5 minutes; then discharge with a constant current of 1C to 3.4V, and then discharge with a constant current of 0.2C to 3.0V. Repeat the above steps 9 times and let it sit for 5 minutes. Then charge it with a constant current of 1C to 4.48V, then charge it with a constant voltage of 4.48V to 0.02C. Finally, let it stand for 5 minutes. Disassemble and observe the groove of the negative electrode tab and the end of the negative electrode. The degree of lithium precipitation.
  • the lithium precipitation area is ⁇ 10%, which is called no lithium precipitation; the lithium precipitation area ⁇ 10% is called lithium precipitation.
  • the perforated tapes of each example and the tapes in the comparative examples were pasted on aluminum foil respectively, cut into 20mm ⁇ 60mm strip samples, and hot-pressed for 40 minutes at a temperature of 85°C and a pressure of 1MPa. , and then soaked in the 85°C electrolyte for 4 hours, the sample was pasted on the steel plate through double-sided tape (Nitong 5000NS) (the adhesion length is not less than 40mm), and the steel plate was fixed at the corresponding position of the high-speed rail tensile machine, and the steel plate was pulled. Pick up the other end of the sample that is not adhered to the steel plate, put the sample into the chuck and clamp it. The angle between the pulled up sample part and the steel plate is 180° in space. The chuck moves at a speed of 50mm/min. Pull, and finally measure the average pulling force in the stable area and record it as the bonding force after soaking in the electrolyte.
  • the positive electrode includes a positive electrode tab.
  • green glue Paste at the following locations: (1) The connection area where the positive electrode tab is connected to the positive electrode; (2) The two negative electrodes adjacent to the positive electrode where the positive electrode tab is located are close to the surface of the positive electrode, and the pasting position corresponds to the location of the above-mentioned connection area.
  • green glue was purchased from Dongguan Aozhong New Material Technology Co., Ltd.
  • the negative electrode includes a negative electrode tab.
  • the negative electrode tab groove is set by laser cleaning.
  • a polyethylene porous polymer film is used as the separator.
  • the adhesive paper includes an adhesive layer disposed on one surface of the base material layer, where the thickness of the adhesive paper is 24 ⁇ m, the thickness of the adhesive layer is 12 ⁇ m, and the thickness of the base material layer is 12 ⁇ m.
  • the molecular weight of polypropylene is 115,000
  • the width of the first perforated area is 8mm
  • the width of the second perforated area is 8mm
  • the width of the non-perforated area 9mm
  • shape of the hole is circular.
  • the base material layer is polyethylene terephthalate film.
  • the pasting position is opposite to the position of the negative electrode tab groove.
  • the positive electrode, separator and negative electrode are stacked in order so that the separator is between the positive electrode and the negative electrode to play an isolation role, and the electrode assembly is obtained by winding.
  • the electrode assembly is placed in an aluminum-plastic film packaging bag, dried and then injected with electrolyte. After vacuum packaging, standing, formation, capacity, degassing, trimming and other processes, a lithium-ion battery is obtained.
  • the formation conditions are to charge to 3.3V with a constant current of 0.02C, then charge to 3.6V with a constant current of 0.1C, and finally charge to 4.45V with a constant current of 0.2C.
  • the lithium-ion batteries in the embodiments of the present application include perforated tape, which can effectively improve the lithium deposition problem of the lithium-ion battery.
  • the sticking position of the perforated tape usually affects the performance of the electrochemical device. From Example 1-1 to Example 1-4, it can be seen that by sticking the perforated tape at a position within the scope of the present application, the performance of the electrochemical device can be improved. Effectively improve the lithium precipitation problem of lithium-ion batteries.
  • the width of the perforated tape w 1 , the width of the first perforated area w 2 , the width of the second perforated area w 3 , the width of the non-perforated area w 4 , the width of the second perforated area and the non-perforated area usually also affect the performance of the electrochemical device, as shown in Examples 1-3, 2-1 to 2-8. It can be seen that by adjusting the above parameters within the scope of the present application, the perforated tape obtained has higher adhesive force, lower swelling thickness and maximum glue overflow width on one side. At the same time, the perforated tape is pasted on this application.
  • the location within the application scope can improve the lithium evolution problem of electrochemical devices.
  • Examples 1-3, 2-7 and 2-8 that when the sum of the areas of the holes in the first perforated area accounts for the proportion of the area of the first perforated area or the second When the total area of the holes in the perforated area accounts for too large a proportion of the area of the second perforated area, the adhesive force of the perforated tape is significantly reduced, but since lithium ions can be transported better, the electrochemical device can be improved Lithium deposition problem; but when the total area of pores in the first perforated area accounts for the ratio of the pore area of the first perforated area or the total area of the pores in the second perforated area accounts for the area of the second perforated area If the ratio is too small, the transmission of lithium ions will be affected, making it impossible to improve the lithium deposition problem of the electrochemical device.
  • the type of polyolefin and/or modified polyolefin in the adhesive layer of the perforated tape and its weight average molecular weight will also affect the performance of the perforated tape and the performance of the electrochemical device. From Examples 1-3 and 3 -1 to Examples 3-7, it can be seen that the perforated adhesive paper produced by selecting the adhesive layer components within the scope of the present application has higher bonding force and lower swelling thickness. and the maximum glue overflow width on one side, and at the same time pasting the perforated tape at a position within the scope of the application, can improve the lithium precipitation problem of the electrochemical device, and is also conducive to improving the safety performance of the electrochemical device.
  • Example 1-3 Example 3-1 to Example 3-4 that when the molecular weight of the polyolefin is within the range of the present application, the perforated adhesive paper has good adhesion and lower The swelling thickness can improve the lithium evolution problem of electrochemical devices.
  • the content of polyolefin and/or modified polyolefin in the adhesive layer of the perforated tape, the type and content of elastomers, fillers, and antioxidants will also affect the performance of the perforated tape and the performance of the electrochemical device. From the implementation It can be seen from Example 1-3, Example 4-1 to Example 4-7 that the adhesive layer components within the scope of the present application are selected to make perforated adhesive paper, and the obtained perforated adhesive paper has higher adhesion. force, lower swelling thickness and maximum glue overflow width on one side, and sticking the perforated tape at a position within the scope of this application can improve the safety performance of the electrochemical device and improve the lithium precipitation problem of the electrochemical device.
  • the thickness of the adhesive layer of the punched tape and the type and thickness of the base material layer will also affect the performance of the punched tape and the performance of the electrochemical device. From Example 1-3, Example 5-1 to Example 5- 6 It can be seen that if the adhesive layer and base material layer within the scope of this application are selected to make the perforated tape, the resulting perforated tape will have higher bonding force, lower swelling thickness and maximum glue overflow width on one side. , and at the same time, pasting the perforated tape at a position within the scope of the present application can improve the lithium deposition problem of the electrochemical device.

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Abstract

本申请提供了一种电化学装置，其包括电极组件，电极组件包括正极、负极和隔膜，隔膜设置于相邻的正极和负极之间，负极包括负极集流体和负极活性物质层，负极中设置有露出负极集流体的负极极耳凹槽，负极极耳固定在负极极耳凹槽中并与负极集流体电连接；在负极极耳表面设置有打孔胶纸，打孔胶纸沿长度方向的边缘设置有孔，打孔胶纸的孔位于打孔胶纸中覆盖在负极极耳凹槽两侧负极活性物质层的部分。通过在电化学装置中按照本申请提供的粘贴打孔胶纸的方式，可以改善电化学装置的析锂问题。

Description

电化学装置和电子装置 技术领域
本申请涉及电化学领域，主要涉及一种电化学装置和电子装置。
背景技术
锂离子电池具有比能量大、工作电压高、自放电率低、体积小、重量轻等特点，广泛应用于电能储存、便携式电子设备和电动汽车等各个领域。随着锂离子电池的使用范围不断扩大，市场对锂离子电池提出了更高的要求，例如要求锂离子电池具有更快的充电速度、更长的使用寿命。
在锂离子电池循环过程中，锂离子容易在负极极耳处的胶纸边缘堆积而造成析锂，导致负极界面恶化，引起循环性能迅速下降和锂离子电池体积膨胀加速。析锂不仅使锂离子电池性能下降，循环寿命大幅缩短，还限制了锂离子电池的快充容量，并有可能引起燃烧、爆炸等后果。有鉴于此，亟需解决锂离子电池循环过程的析锂问题。
发明内容
本申请的目的在于提供一种电化学装置和电子装置，以改善电化学装置的析锂问题。具体技术方案如下：
本申请的第一方面提供了一种电化学装置，其包括电极组件，所述电极组件包括正极、负极和隔膜，所述隔膜设置于相邻的所述正极和所述负极之间；所述负极包括负极集流体和设置在所述负极集流体至少一个表面的负极活性物质层，所述负极中设置有露出所述负极集流体的负极极耳凹槽，负极极耳固定在所述负极极耳凹槽中并与所述负极集流体电连接；其中，所述负极极耳表面设置有打孔胶纸，所述打孔胶纸沿长度方向的边缘设置有孔，所述打孔胶纸的孔位于所述打孔胶纸中覆盖所述负极极耳凹槽两侧负极活性物质层的部分。
本申请发明人经深入研究发现，通过在负极极耳凹槽位置粘贴打孔胶纸，并且使打孔胶纸的孔位于负极极耳凹槽两侧负极活性物质层的部分，在避免负极极耳周围的毛刺影响电化学装置安全性能的同时，通过在打孔胶纸长度方向边缘打孔，锂离子能够穿过打孔胶纸的孔在正极和负极之间传输，减少锂离子在打孔胶纸边缘堆积，从而分散打孔胶纸周围的锂离子，改善负极极耳槽位的析锂现象，进一步改善电化学装置的析锂问题。
在本申请的一种实施方案中，所述正极包括相对的第一表面和第二表面，所述第一表 面靠近所述负极；所述打孔胶纸还粘贴在所述第一表面与所述负极极耳凹槽相对应的位置上。本申请发明人经深入研究发现，通过将打孔胶纸粘贴在上述正极的第一表面上，可以分散打孔胶纸周围的锂离子，改善电化学装置的析锂问题。
在本申请的一种实施方案中，所述打孔胶纸还粘贴在所述第二表面与所述负极极耳凹槽相对应的位置上。本申请发明人经深入研究发现，将打孔胶纸粘贴在上述位置，可以改善电化学装置的析锂问题。
在本申请的一种实施方案中，所述打孔胶纸绕过所述正极端部边缘还粘贴在所述第二表面与所述负极极耳凹槽相对应的位置上。本申请发明人经深入研究发现，将打孔胶纸粘贴在上述位置，可以改善负极端部的析锂现象，进一步改善电化学装置的析锂问题。
在本申请的一种实施方案中，沿所述打孔胶纸的宽度方向设置有第一打孔区、第二打孔区和非打孔区，所述非打孔区位于所述第一打孔区和所述第二打孔区之间，所述打孔胶纸的宽度w 1为6mm至30mm，所述第一打孔区的宽度为w 2，所述第二打孔区的宽度为w 3，w 2和w 3各自独立地选自1mm至10mm，所述非打孔区的宽度w 4为2mm至10mm，所述第一打孔区的宽度或所述第二打孔区的宽度与所述非打孔区的宽度比为0.5:1至1:1。本申请发明人经深入研究发现，通过控制打孔胶纸的宽度满足上述要求，协同控制第一打孔区、第二打孔区和非打孔区的宽度在上述范围内，可以进一步改善电化学装置的析锂问题。
在本申请的一种实施方案中，所述打孔胶纸的孔满足如下特征中的至少一者：(1)孔的间距b为0mm至2mm，孔的轮廓的外接圆最小直径c为0.1mm至3mm；(2)第一打孔区中孔的面积的总和占第一打孔区的面积的比例为20％至80％，第二打孔区中孔的面积的总和占第二打孔区的面积的比例为20％至80％；(3)孔的形状为圆形、椭圆形、多边形中的至少一种。本申请发明人经研究发现，通过控制打孔胶纸的孔满足上述特征中的一种、两种或两种以上的组合，能够改善电化学装置的析锂问题。
在本申请的一种实施方案中，所述打孔胶纸包括胶层和基材层，所述胶层包含聚烯烃和/或改性聚烯烃，以及弹性体、填料和抗氧剂，基于所述胶层的总质量，所述聚烯烃和/或改性聚烯烃的质量百分含量为45％至85％，所述弹性体的质量百分含量为10％至35％，所述填料的质量百分含量为2％至10％，所述抗氧剂的质量百分含量为2％至10％。本申请发明人经研究发现，通过协同控制胶层中各组分的质量百分含量在上述范围内，有利于提高打孔胶纸的耐电解液性能、粘结力，降低溶胀度，进而提高电化学装置的安全性能、延 长电化学装置的使用寿命并控制成本。
在本申请的一种实施方案中，所述胶层满足如下特征中的至少一者：(1)所述聚烯烃包括聚乙烯和/或聚丙烯，所述改性聚烯烃包括马来酸酐改性聚乙烯和/或马来酸酐改性聚丙烯，所述聚烯烃和改性聚烯烃的重均分子量各自独立地选自30000至200000；(2)所述弹性体包括苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物、聚氨酯、聚酰胺、聚丁二烯或聚异丁烯中的至少一种；(3)所述填料包括钛白粉、滑石粉、白炭黑或碳酸钙中的至少一种；(4)所述抗氧剂包括二苯胺、亚磷酸三甲酯、亚磷酸三乙酯或硫代二丙酸双十八醇酯中的至少一种。本申请发明人经研究发现，通过控制打孔胶纸的胶层满足上述条件中的一种、两种或两种以上的组合，能够进一步改善电化学装置的析锂问题，提高电化学装置的安全性能。
在本申请的一种实施方案中，所述基材层包括聚对苯二甲酸乙二醇酯、聚酰亚胺或聚丙烯中的至少一种。本申请发明人经研究发现，通过选择上述材料作为基材层，有利于提高打孔胶纸耐电解液性能，从而改善电化学装置的析锂问题，提高电化学装置的安全性能。
在本申请的一种实施方案中，胶层的厚度为4μm至20μm，基材层的厚度为4μm至30μm。本申请发明人经研究发现，通过控制打孔胶纸中胶层的厚度及基材层的厚度在上述范围内，能够维持电化学装置能量密度的同时改善电化学装置的安全性能。
在本申请的一种实施方案中，所述打孔胶纸在85℃电解液中浸泡4h后的粘结力为0.2N/mm至0.5N/mm，本申请发明人经研究发现，当打孔胶纸的粘结力在上述范围内时，有利于改善电化学装置的析锂问题，提高电化学装置的安全性能。
在本申请的一种实施方案中，所述打孔胶纸在85℃电解液中浸泡24h的厚度A与未经所述电解液浸泡的厚度B满足：0μm<A-B≤2μm，即本申请提供的打孔胶纸的溶胀度低，有利于改善电化学装置的安全性能和析锂问题。
在本申请的一种实施方案中，所述打孔胶纸的单边最大溢胶宽度为0mm至1mm，即本申请提供的打孔胶纸具有良好的热稳定性，有利于改善电化学装置的安全性能。
本申请提供了一种电化学装置和电子装置，电化学装置包括电极组件，电极组件包括正极、负极和隔膜，负极包括负极集流体和设置在负极集流体至少一个表面的负极活性物质层，负极中设置有露出负极集流体的负极极耳凹槽，负极极耳固定在负极极耳凹槽中并与负极集流体电连接；其中，负极极耳表面设置有打孔胶纸，打孔胶纸沿长度方向的边缘设置有孔，打孔胶纸的孔位于打孔胶纸中覆盖负极极耳凹槽两侧负极活性物质层的部分。 通过在电化学装置中粘贴上述打孔胶纸，能够有效降低电化学装置的析锂程度。本申请的电子装置包括本申请的电化学装置，因此，本申请的电子装置也具有良好的安全性能。
当然，实施本申请的任一实施方案并不一定需要同时达到以上所述的所有优点。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面对实施例中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，本领域普通技术人员来讲还可以根据这些附图获得其他的附图。
图1为本申请一些实施例的电极组件沿厚度方向的剖面结构示意图；
图2为图1中A处的局部放大图；
图3为本申请另一些实施例中的负极粘贴打孔胶纸的结构示意图；
图4为本申请一些实施例的打孔胶纸的结构示意图；
图5为本申请一些实施例的电极组件沿厚度方向的剖面结构示意图；
图6为图5中B处的局部放大图；
图7为本申请一些实施例的电化学装置沿厚度方向的剖面结构示意图；
图8为图7中C处的局部放大图；
图9为本申请一些实施例的电化学装置沿长度方向的局部剖面结构示意图；
图10为本申请另一些实施例的电化学装置沿长度方向的局部剖面结构示意图。
附图标记：10.负极；11.负极极耳；12.负极集流体；13.负极活性物质层；14.负极极耳凹槽；20.隔膜；30.正极；31.正极极耳；32.正极集流体；33.正极活性物质层；40.打孔胶纸；41.孔；42.第一打孔区；43.第二打孔区；44.非打孔区；50.绿胶。
具体实施方式
为使本申请的目的、技术方案、及优点更加清楚明白，以下参照附图并举实施例，对本申请进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。本领域普通技术人员基于本申请中的实施例所获得的所有其他实施例，都属于本申请保护的范围。
需要说明的是，本申请的具体实施方式中，以锂离子电池作为电化学装置的例子来解释本申请，但是本申请的电化学装置并不仅限于锂离子电池。
现有技术的锂离子电池循环过程中，由于锂离子在传输过程中会在负极极耳的胶纸边缘堆积而造成析锂。为了解决上述技术问题，本申请提供了一种电化学装置和电子装置。
本申请的第一方面提供了一种电化学装置，其包括电极组件，电极组件包括正极、负极和隔膜，隔膜设置于相邻的正极和负极之间；负极包括负极集流体和设置在负极集流体至少一个表面的负极活性物质层，负极中设置有露出负极集流体的负极极耳凹槽，负极极耳固定在负极极耳凹槽中并与负极集流体电连接；其中，负极极耳表面设置有打孔胶纸，打孔胶纸沿长度方向的边缘设置有孔，打孔胶纸的孔位于打孔胶纸中覆盖负极极耳凹槽两侧负极活性物质层的部分。
示例性地，如图1至图3所示，为了方便说明，以电极组件的宽度方向为x方向，电极组件的长度方向为y方向，以电极组件的厚度方向为z方向建立三维直角坐标系。电极组件包括负极10、正极30、位于正极30与负极10之间的隔膜20、打孔胶纸40、绿胶50，正极30包括正极极耳31、正极集流体32和正极活性物质层33，负极10包括负极极耳11、负极集流体12、负极活性物质层13和负极极耳凹槽14。沿电极组件宽度方向(x方向)，打孔胶纸40粘贴在负极极耳11与负极10连接的区域，且覆盖负极极耳凹槽14，可以理解的是，打孔胶纸40的面积大于负极极耳凹槽14的面积，同时打孔胶纸40的孔41位于打孔胶纸40中覆盖负极极耳凹槽14两侧负极活性物质层13的部分。其中，负极极耳凹槽14两侧的负极活性物质层13的部分是指负极极耳凹槽14两侧的负极活性物质层13的部分表面，也即沿电极组件厚度方向(z方向)，打孔胶纸40的孔41在负极10上的正投影与负极极耳凹槽14在负极10上的正投影完全不重叠，如图3所示。
示例性地，如图4所示，为了方便说明，以打孔胶纸的长度方向为y’方向，打孔胶纸的宽度方向为x’方向建立平面直角坐标系。在打孔胶纸40的长度方向(y’方向)的边缘设置贯穿打孔胶纸40的孔41。其中，打孔胶纸40的长度方向(y’方向)的边缘是指沿打孔胶纸宽度方向(x’方向)相对的两个边缘。可以理解的是，打孔胶纸的孔可以均匀设置，也可以不均匀设置，只要能实现本申请的目的即可。
本申请发明人经深入研究发现，通过在负极极耳凹槽位置粘贴打孔胶纸，并且使打孔胶纸的孔位于负极极耳凹槽两侧的部分，在避免负极极耳周围的毛刺影响电化学装置安全性能的同时，通过在胶纸长度方向边缘设置贯穿打孔胶纸的孔，使得锂离子能够穿过打孔胶纸的孔在正极和负极之间传输(如图2中箭头所示，为锂离子的传输方向)，减少锂离子在打孔胶纸边缘堆积，从而分散打孔胶纸周围的锂离子，改善负极极耳槽位析锂现象，进一步改善电化学装置的析锂问题。
在本申请中，正极极耳为正极上引出的金属导体，负极极耳为负极上引出的金属导体， 正极极耳和负极极耳用于串联连接或并联连接电化学装置的其它部分。本申请对正极极耳和负极极耳的材料没有特别限制，只要能实现本申请的目的即可，例如可以采用本领域已知的正极极耳和负极极耳的材料。本申请对负极极耳凹槽的形成方式没有特别限制，可以采用本领域已知的形成方式，只要能实现本申请的目的即可，例如，可以通过在相应负极区域采用激光清洗，或者，通过先在负极集流体上粘贴发泡胶纸，涂布负极活性物质层并烘干，剥离发泡胶纸即可得到负极极耳凹槽。
在本申请的一种实施方案中，正极包括相对的第一表面和第二表面，第一表面靠近负极；打孔胶纸还粘贴在第一表面与负极极耳凹槽相对应的位置上。示例性地，如图5和图6所示，打孔胶纸40分别粘贴在负极极耳凹槽14表面，以及正极30的第一表面的正极活性物质层33的表面，且粘贴位置与负极极耳凹槽14位置对应。本申请发明人经深入研究发现，通过将打孔胶纸粘贴在上述正极的第一表面上，与现有技术使用未打孔胶纸粘贴相应位置相比，可以分散打孔胶纸周围的锂离子，进一步改善电化学装置的析锂问题。在本申请中，正极的第一表面和第二表面为沿正极厚度方向的两个相对的表面，其中，正极的厚度方向与电极组件的厚度方向(z方向)相同。
此外，在电化学装置使用过程中，锂离子会从正极的端部传输至相邻的负极，导致负极的端部析锂。其中，正极的端部是指沿负极极耳伸出方向，正极沿自身长度方向且靠近负极极耳的一侧；负极的端部是指沿负极极耳伸出方向，负极沿自身长度方向且靠近负极极耳的一侧。正极自身长度方向和负极自身长度方向与电极组件的宽度方向(x方向)相同。
在本申请的一种实施方案中，打孔胶纸还可以粘贴在第二表面与负极极耳凹槽相对应的位置上。示例性地，如图7至图9所示，打孔胶纸40粘贴在负极极耳凹槽14表面，打孔胶纸40还分别粘贴在正极30的第一表面和第二表面中与负极极耳凹槽14相对应的位置上。本申请发明人经研究发现，通过将打孔胶纸分别粘贴在上述第一表面和第二表面与负极极耳凹槽相对应的位置上，能够改善锂离子传输受阻导致的析锂问题，以及锂离子从正极端部扩散至相邻的负极端部的问题，可以改善负极端部析锂，进一步改善电化学装置的析锂问题。
在本申请的一种实施方案中，打孔胶纸绕过正极端部边缘还粘贴在第二表面与负极极耳凹槽相对应的位置上。示例性地，如图10所示，打孔胶纸40粘贴在负极极耳凹槽14表面，打孔胶纸40还粘贴在正极30的第一表面和第二表面与负极极耳凹槽14相对应的 位置上，且打孔胶纸40绕过正极30的端部将正极30的端部包裹。本申请发明人经深入研究发现，使用打孔胶纸在正极端部通过包裹的方式进行粘贴，能更好地改善锂离子从正极端部扩散至相邻的负极端部的问题，从而改善负极端部析锂，进一步改善电化学装置的析锂问题。
在本申请的一种实施方案中，示例性地，如图4所示，沿打孔胶纸40的宽度方向(x’方向)设置有第一打孔区42、第二打孔区43和非打孔区44，非打孔区44位于第一打孔区42和第二打孔区43之间。打孔胶纸40的宽度w 1为6mm至30mm，例如，w 1可以为6mm、12mm、18mm、24mm、30mm或为其间的任意范围。第一打孔区42的宽度为w 2，第二打孔区43的宽度为w 3，w 2和w 3各自独立地选自1mm至10mm，例如w 2可以为1mm、2.5mm、5mm、7.5mm、10mm或为其间的任意范围，w 3可以为1mm、2.5mm、5mm、7.5mm、10mm或为其间的任意范围。非打孔区44的宽度w 4为2mm至10mm，例如，w 4可以为2mm、4mm、6mm、8mm、10mm或为其间的任意范围。第一打孔区42的宽度或第二打孔区43的宽度与非打孔区44的宽度比为0.5:1至1:1，例如，w 2:w 4可以为0.5:1、0.6:1、0.7:1、0.8:1、0.9:1、1:1或为其间的任意范围，w 3:w 4可以为0.5:1、0.6:1、0.7:1、0.8:1、0.9:1、1:1或为其间的任意范围。
本申请人经深入研究发现，通过控制打孔胶纸的宽度，协同控制第一打孔区、第二打孔区和非打孔区的宽度在上述范围内，能够使锂离子更好分散，以改善锂离子在打孔胶纸周围堆积的现象，从而进一步改善电化学装置的析锂问题。在本申请中，第一打孔区与第二打孔区的宽度可以相等或不相等。
在本申请的一种实施方案中，打孔胶纸的孔满足如下特征中的至少一者：
(1)孔的间距b为0mm至2mm，孔的轮廓的外接圆最小直径c为0.1mm至3mm，如图4所示，孔41的间距即为两个相邻的孔41的轮廓之间的最小的直线距离。例如，b可以为0mm、0.1mm、0.5mm、1mm、1.5mm、2mm或为其间的任意范围，c可以为0.1mm、0.5mm、1mm、1.5mm、2mm、2.5mm、3mm或为其间的任意范围。本申请发明人经研究发现，通过使孔的间距和直径满足上述范围，可以使打孔胶纸中的孔分散的更加均匀，使锂离子能够更好的在正极、负极之间传输，从而改善电化学装置的析锂问题。
(2)第一打孔区中孔的面积的总和占第一打孔区的面积的比例为20％至80％，优选为30％至70％；第二打孔区中孔的面积的总和占第二打孔区的面积的比例为20％至80％优选为30％至70％。例如，第一打孔区中孔的面积的总和占第一打孔区的面积的比例可以为 20％、30％、40％、50％、60％、70％、80％或为其间的任意范围，第二打孔区中孔的面积的总和占第二打孔区的面积的比例可以为20％、30％、40％、50％、60％、70％、80％或为其间的任意范围。
本申请发明人经研究发现，第一打孔区中孔的面积的总和占第一打孔区的面积的比例，或者，第二打孔区中孔的面积的总和占第二打孔区的面积的比例过小时(例如小于20％)，锂离子无法有效通过打孔胶纸的孔进行分散，容易在打孔胶纸周围进行堆积，对电化学装置析锂问题改善不明显；当第一打孔区中孔的面积的总和占第一打孔区的面积的比例，或者，第二打孔区中孔的面积的总和占第二打孔区的面积的比例过大时(例如大于80％)，打孔胶纸粘结力下降，无法有效束缚负极极耳，会影响电化学装置的安全性能。因此，通过控制第一打孔区和第二打孔区中孔的面积在上述范围内，能够改善电化学装置的析锂问题，以及使电化学装置具有良好的安全性能。
(3)孔的形状为圆形、椭圆形、多边形中的至少一种，其中，多边形可以包括但不限于三角形、四边形、五边形等，上述孔的形状更有利于打孔胶纸的制备。本申请发明人经研究发现，通过控制打孔胶纸的孔满足上述特征中的一种、两种或两种以上的组合，能够改善电化学装置的析锂问题。
在本申请的一种实施方案中，打孔胶纸包括胶层和基材层，胶层包含聚烯烃和/或改性聚烯烃，以及弹性体、填料和抗氧剂。基于胶层的总质量，聚烯烃和/或改性聚烯烃的质量百分含量为45％至85％，例如，聚烯烃和/或改性聚烯烃的质量百分含量可以为45％、50％、60％、70％、80％、85％或为其间的任意范围。其中，当仅包含聚烯烃而不包含改性聚烯烃，聚烯烃和/或改性聚烯烃的质量百分含量是指聚烯烃的质量百分含量；当仅包含改性聚烯烃而不包含聚烯烃，聚烯烃和/或改性聚烯烃的质量百分含量是指改性聚烯烃的质量百分含量；当同时包含聚烯烃和改性聚烯烃，聚烯烃和/或改性聚烯烃的质量百分含量是指聚烯烃和改性聚烯烃的质量百分含量之和。弹性体的质量百分含量为10％至35％，例如，弹性体的质量百分含量可以为10％、15％、20％、25％、30％、35％或为其间的任意范围。填料的质量百分含量为2％至10％，例如，填料的质量百分含量可以为2％、4％、6％、8％、10％或为其间的任意范围。抗氧剂的质量百分含量为2％至10％，例如，抗氧剂的质量百分含量可以为2％、4％、6％、8％、10％或为其间的任意范围。
本申请发明人经研究发现，当聚烯烃和/或改性聚烯烃的质量百分含量过低时(例如低于45％)，会影响打孔胶纸的耐电解液性能、粘结力和溶胀度性能。当聚烯烃和/或改性聚 烯烃的质量百分含量过高时(例如高于85％)，会造成胶层柔韧性变差以及聚烯烃和/或改性聚烯烃的浪费，导致电化学装置的成本提高。通过调控聚烯烃和/或改性聚烯烃的质量百分含量在上述范围内，有利于提高打孔胶纸的耐电解液性能、粘结力，降低溶胀度，使打孔胶纸能够有效束缚负极极耳，从而提高电化学装置的安全性能、延长电化学装置的使用寿命并控制成本。此外，进一步协同控制胶层中各组分的质量百分含量在上述范围内，有利于提高打孔胶纸的耐电解液性能、粘结力，降低溶胀度，从而改善电化学装置的安全性能，延长电化学装置的寿命。
在本申请的一种实施方案中，胶层满足如下特征中的至少一者：
(1)聚烯烃包括聚乙烯和/或聚丙烯，改性聚烯烃包括马来酸酐改性聚乙烯和/或马来酸酐改性聚丙烯，聚烯烃和改性聚烯烃的重均分子量各自独立地选自30000至200000，例如，聚烯烃的重均分子量可以为30000、55000、100000、155000、200000或为其间的任意范围，改性聚烯烃重均分子量可以为30000、55000、100000、155000、200000或为其间的任意范围。本申请发明人经研究发现，通过调控聚烯烃和改性聚烯烃的重均分子量在上述范围内，有利于提高打孔胶纸的粘结力，使打孔胶纸能够有效束缚极耳，同时减少打孔胶纸在电解液中长时间浸泡后从打孔胶纸下方析出的锂离子数量，进一步改善电化学装置的析锂问题，提高电化学装置的安全性能。
(2)弹性体包括苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物、聚氨酯、聚酰胺、聚丁二烯或聚异丁烯中的至少一种，其中，弹性体是指在弱应力下形变显著，应力松弛后能迅速恢复到接近原有状态和尺寸的高分子材料。本申请发明人经研究发现，通过在胶层中添加上述弹性体能够进一步提高打孔胶纸的粘结力，当打孔胶纸的粘结力过低时，不能有效束缚负极极耳，同时在电解液中长时间浸泡，锂离子容易从打孔胶纸的下方析出，导致电化学装置析锂。通过选择上述弹性体，可以改善电化学装置的析锂问题，提高电化学装置的安全性能。
(3)填料包括钛白粉、滑石粉、白炭黑或碳酸钙中的至少一种，本申请发明人经研究发现，通过选择上述填料，有利于提高打孔胶纸耐电解液的性能，当打孔胶纸在电解液中长时间浸泡时，能够减缓打孔胶纸下方锂离子的析出，进一步改善电化学装置的析锂问题，提高电化学装置的安全性能。
(4)抗氧剂包括二苯胺、亚磷酸三甲酯、亚磷酸三乙酯或硫代二丙酸双十八醇酯中的至少一种，本申请发明人经研究发现，通过选择上述抗氧剂可以提高打孔胶纸耐电解液 的性能，当打孔胶纸在电解液中长时间浸泡时，能够减缓打孔胶纸下方锂离子的析出，进一步改善电化学装置的析锂问题，提高电化学装置的安全性能。
本申请发明人经研究发现，通过控制打孔胶纸的胶层满足上述条件中的一种、两种或两种以上的组合，能够进一步改善电化学装置的安全性能和析锂问题。
在本申请的一种实施方案中，基材层包括聚对苯二甲酸乙二醇酯、聚酰亚胺或聚丙烯中的至少一种。本申请发明人经研究发现，通过选择上述材料作为基材层，有利于提高打孔胶纸耐电解液性能，当打孔胶纸在电解液中长时间浸泡时，能够减缓打孔胶纸下方锂离子的析出，进一步改善电化学装置的析锂问题，提高电化学装置的安全性能。
在本申请的一种实施方案中，胶层的厚度为4μm至20μm，例如，胶层的厚度可以为4μm、5μm、8μm、10μm、12μm、15μm、18μm、20μm或为其间的任意范围；基材层的厚度为4μm至30μm，例如，基材层的厚度可以为4μm、5μm、10μm、12μm、20μm、25μm、30μm或为其间的任意范围。本申请发明人经研究发现，当胶层厚度过小时(例如小于4μm)，在电解液中浸泡更容易发生性能变化，影响打孔胶纸的粘结力，进而影响电化学装置的安全性能。在一定范围内，胶纸的粘结力随胶层厚度的增大呈现增强的趋势，但是当胶层的厚度过大时(例如大于20μm)，胶层的粘结力趋于不变，但会影响电化学装置的能量密度。当基材层的厚度过小时(例如小于4μm)，对胶层的支撑作用弱，造成其对负极极耳的固定效果变差，当基材层的厚度过大时(例如大于30μm)，作用效果与本申请范围内的实施例相当，但会影响电化学装置的能量密度。通过控制打孔胶纸中胶层的厚度及基材层的厚度在上述范围内，能够维持电化学装置的能量密度，并且提高电化学装置的安全性能。
在本申请的一种实施方案中，打孔胶纸在85℃电解液中浸泡4h后的粘结力为0.2N/mm至0.5N/mm，即本申请的打孔胶纸具有良好的粘结力，能够有效束缚极耳，有利于改善电化学装置的安全性能，当打孔胶纸的粘结力过低时(小于0.2N/mm)，在电解液中长时间浸泡，锂离子容易从打孔胶纸的下方析出，导致电化学装置析锂。通过调控打孔胶纸的粘结力在上述范围内时，可以改善电化学装置的析锂问题。例如，打孔胶纸在85℃电解液中浸泡4h后的粘结力可以为0.2N/mm、0.3N/mm、0.4N/mm、0.5N/mm或为其间的任意范围。其中，打孔胶纸在85℃电解液中浸泡4h后的粘结力测试是先将打孔胶纸热压后，再放入电解液中进行浸泡，最后测试其粘结力。
在本申请的一种实施方案中，打孔胶纸在85℃电解液中浸泡24h的厚度A与未经电解 液浸泡的厚度B满足：0μm<A-B≤2μm，即本申请提供的打孔胶纸的溶胀度低，有利于改善电化学装置的安全性能，当打孔胶纸的溶胀度过高(A-B大于2μm)，锂离子传输受阻，影响电化学装置的倍率性能。通过调控打孔胶纸的溶胀度在上述范围内时，可以在改善电化学装置的析锂问题的同时保持其倍率性能。例如，A-B的值可以为0.01μm、0.5μm、1μm、1.5μm、2μm或为其间的任意范围。
在本申请的一种实施方案中，打孔胶纸的单边最大溢胶宽度为0mm至1mm，即本申请提供的打孔胶纸具有良好的热稳定性，从而能够更好的束缚负极极耳，提高电化学装置的安全性能。例如，打孔胶纸的单边最大溢胶宽度可以为0mm、0.1mm、0.2mm、0.3mm、0.4mm、0.5mm、0.6mm、0.7mm、0.8mm、0.9mm、1mm或为其间的任意范围。在本申请中，打孔胶纸的单边最大溢胶宽度是指将打孔胶纸在温度为85℃、压力为1MPa下热压处理1h后打孔胶纸的最大宽度与未进行热压处理的打孔胶纸的宽度之差的二分之一。
在本申请中，打孔胶纸还可以包括离型纸，离型纸设置于胶层背向基材层的表面。打孔胶纸中离型纸的设置是用于防止胶层表面接触到非贴附目标表面或自身，以避免在打孔胶纸使用过程中，胶层与非贴附目标表面或自身发生粘粘，本领域技术人员可以根据实际需要选择本领域中任何合适的离型纸材料或尺寸。在一些实施例中，离型纸可以单面设置于胶层任何暴露的表面上，例如，但不限于，胶层背向基材层的表面或胶层侧边的表面。在一些实施例中，离型纸在打孔胶纸中胶层粘贴到目标表面前撕除。在一些实施例中，离型纸包含单面硅离型膜或双面硅离型膜。
本申请对打孔胶纸的制备方法没有特别限制，只要能够实现本申请目的即可。例如，本申请可以采用如下制备打孔胶纸的方法，其包括以下步骤：将胶层的原料按照一定比例混合得到胶层浆料，然后在基材层上涂布胶层浆料，烘干后得到胶纸，进一步在胶纸长度方向的边缘打孔。本申请对打孔的方式没有特别限定，只要能实现本申请的目的即可，例如可以通过激光打孔或机械打孔中的一种。其中，基材层可以先用非硅离型剂处理然后对表面进行电晕处理，烘干温度可以为60℃至120℃。
本申请中的正极没有特别限制，只要能实现本申请的目的即可，例如，正极通常包括正极集流体和正极活性物质层。其中，正极集流体没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于铝箔、铝合金箔或复合集流体等。在本申请中，对正极集流体的厚度没有特别限制，只要能够实现本申请目的即可，例如厚度为8μm至12μm。在本申请中，正极活性物质层可以设置于正极集流体厚度方向上的一个表面上，也可以设置 于正极集流体厚度方向上的两个表面上。需要说明，这里的“表面”可以是正极集流体的全部区域，也可以是正极集流体的部分区域，本申请没有特别限制，只要能实现本申请目的即可。
在本申请中，正极活性物质层包括正极活性材料，其中，正极活性材料没有特别限制，只要能够实现本申请目的即可，例如可以包括锂和过渡金属元素的复合氧化物中的至少一种。本申请对上述过渡金属元素没有特别限制，只要能实现本申请的目的即可，例如可以包括镍、锰、钴或铁中的至少一种。具体的，正极活性材料可以包括镍钴锰酸锂(811、622、523、111)、镍钴铝酸锂、磷酸铁锂、富锂锰基材料、钴酸锂、锰酸锂、磷酸铁锂或钛酸锂中的至少一种。
在本申请中，正极活性物质层中还可以包括导电剂，本申请对导电剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于导电炭黑(Super P)、碳纳米管(CNTs)、碳纤维、鳞片石墨、科琴黑、石墨烯、金属材料或导电聚合物中的至少一种。上述碳纳米管可以包括但不限于单壁碳纳米管和/或多壁碳纳米管。上述碳纤维可以包括但不限于气相生长碳纤维(VGCF)和/或纳米碳纤维。上述金属材料可以包括但不限于金属粉和/或金属纤维，具体地，金属可以包括但不限于铜、镍、铝或银中的至少一种。上述导电聚合物可以包括但不限于聚亚苯基衍生物、聚苯胺、聚噻吩、聚乙炔或聚吡咯中的至少一种。
在本申请中，正极活性物质层中还可以包括粘结剂，本申请对粘结剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于聚丙烯酸、聚丙烯酸钠、聚丙烯酸钾、聚丙烯酸锂、聚酰亚胺、聚乙烯醇、羧甲基纤维素、羧甲基纤维素钠、羧甲基纤维素锂、聚酰亚胺、聚酰胺酰亚胺、丁苯橡胶或聚偏氟乙烯中的至少一种。
任选地，正极还可以包括导电层，导电层位于正极集流体和正极活性物质层之间。本申请对导电层的组成没有特别限制，可以是本领域常用的导电层，例如可以包括但不限于上述导电剂和上述粘结剂。
在本申请中，负极活性物质层可以设置于负极集流体厚度方向上的一个表面上，也可以设置于负极集流体厚度方向上的两个表面上。需要说明，这里的“表面”可以是负极集流体的全部区域，也可以是负极集流体的部分区域，本申请没有特别限制，只要能实现本申请目的即可。
本申请中的负极集流体没有特别限制，只要能实现本申请的目的即可，例如可以包括 但不限于铜箔、铜合金箔、镍箔、不锈钢箔、钛箔、泡沫镍、泡沫铜或复合集流体等。在本申请中，对负极的集流体的厚度没有特别限制，只要能够实现本申请目的即可，例如厚度为4μm至12μm。
本申请中，负极活性物质层包括负极活性材料，其中，负极活性材料没有特别限制，只要能实现本申请的目的即可，例如可以包括但不限于天然石墨、人造石墨、中间相微碳球、硬碳、软碳、硅、硅-碳复合物、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO 2、尖晶石结构的锂化TiO 2-Li 4Ti 5O 12或Li-Al合金中的至少一种。
在本申请中，负极活性物质层中还可以包括导电剂，本申请对导电剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于上述导电剂中的至少一种。
在本申请中，负极活性物质层中还可以包括粘结剂，本申请对粘结剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于上述粘结剂中的至少一种。
任选地，负极还可以包括导电层，导电层位于负极集流体和负极活性物质层之间。本申请对导电层的组成没有特别限制，可以是本领域常用的导电层，导电层可以包括但不限于上述导电剂和上述粘结剂。
本申请的电化学装置还包括隔膜，本申请对隔膜没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于聚乙烯(PE)、聚丙烯(PP)、聚四氟乙烯为主的聚烯烃(PO)类隔膜、聚酯膜(例如聚对苯二甲酸乙二醇酯(PET)膜)、纤维素膜、聚酰亚胺膜(PI)、聚酰胺膜(PA)、氨纶、芳纶膜、织造膜、无纺布、微孔膜、复合膜、隔膜纸、碾压膜或纺丝膜等中的至少一种。本申请的隔膜可以具有多孔结构，孔径的尺寸没有特别限制，只要能实现本申请的目的即可，例如，孔径的尺寸可以为0.01μm至1μm。在本申请中，隔膜的厚度没有特别限制，只要能实现本申请的目的即可，例如厚度可以为5μm至500μm。
例如，隔膜可以包括隔膜基材层和表面处理层。隔膜基材层可以为具有多孔结构的无纺布、膜或复合膜，隔膜基材层的材料可以包括但不限于聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯或聚酰亚胺等中的至少一种。任选地，可以使用聚丙烯多孔膜、聚乙烯多孔膜、聚丙烯无纺布、聚乙烯无纺布或聚丙烯-聚乙烯-聚丙烯多孔复合膜。任选地，隔膜基材层的至少一个表面上设置有表面处理层，表面处理层可以是聚合物层或无机物层，也可以是将聚合物与无机物混合所形成的层。
聚合物层中包含聚合物，聚合物的材料可以包括但不限于聚丙烯、聚酰胺、聚丙烯腈、 丙烯酸酯聚合物、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚偏氟乙烯或聚偏氟乙烯-六氟丙烯等中的至少一种。无机物层可以包括但不限于无机颗粒和粘结剂，本申请对无机颗粒没有特别限制，例如，可以包括但不限于氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙或硫酸钡等中的至少一种。本申请对无机物层中的粘结剂没有特别限制，例如可以包括但不限于聚偏氟乙烯、聚偏氟乙烯-六氟丙烯共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯或聚六氟丙烯中的至少一种。
本申请的电化学装置没有特别限制，其可以包括发生电化学反应的任何装置。在一些实施方案中，电化学装置可以包括但不限于：锂金属二次电池、锂离子二次电池(锂离子电池)、锂聚合物二次电池或锂离子聚合物二次电池等。
电化学装置的制备过程为本领域技术人员所熟知的，本申请没有特别的限制，例如，可以包括但不限于以下步骤：将正极、隔膜和负极按顺序堆叠，并根据需要将其卷绕、折叠等操作得到卷绕结构的电极组件，将电极组件放入包装袋内，将电解液注入包装袋并封口，得到电化学装置；或者，将正极、隔膜和负极按顺序堆叠，然后用胶带将整个叠片结构的四个角固定好得到叠片结构的电极组件，将电极组件置入包装袋内，将电解液注入包装袋并封口，得到电化学装置。此外，也可以根据需要将防过电流元件、导板等置于包装袋中，从而防止电化学装置内部的压力上升、过充放电。
本申请的第二方面提供了一种电子装置，其包含本申请第一方面提供的电化学装置。
本申请的电子装置没有特别限定，其可以是用于现有技术中已知的任何电子装置。在一些实施例中，电子装置可以包括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。
实施例
以下，举出实施例及对比例来对本申请的实施方式进行更具体地说明。各种的试验及评价按照下述的方法进行。另外，只要无特别说明，“份”、“％”为质量基准。
测试方法和设备：
析锂测试：
(1)10℃下锂离子电池的析锂测试：在10℃下，将锂离子电池静置5min，以1.5C的电流恒流充电至4.25V，然后以1.2C的电流恒流充电至4.48V，然后4.48V恒压充电至0.02C；静置5min，以1C的电流恒流放电至3.4V，再以0.2C的电流恒流放电至3.0V。重复上述步骤9次后静置5min，然后以1C的电流恒流充电至4.48V，然后4.48V恒压充电至0.02C，最后静置5min，拆解观察负极极耳凹槽和负极端部的析锂程度。
(2)25℃下锂离子电池的析锂测试：在25℃下，将锂离子电池静置5min，以1.5C的电流恒流充电至4.25V，然后以1.2C的电流恒流充电至4.48V，然后4.48V恒压充电至0.02C，静置5min；接着以1C的电流恒流放电至3.4V，再以0.2C的电流恒流放电至3.0V。重复上述步骤9次后静置5min，然后以1C的电流恒流充电至4.48V，然后4.48V恒压充电至0.02C，最后静置5min，拆解观察负极极耳凹槽和负极端部的析锂程度。
(3)45℃下锂离子电池的析锂测试：在45℃下，将锂离子电池静置5min，以1.5C的电流恒流充电至4.25V，然后以1.2C的电流恒流充电至4.48V，然后4.48V恒压充电至0.02C，静置5min；接着以1C的电流恒流放电至3.4V，再以0.2C的电流恒流放电至3.0V。重复上述步骤9次后静置5min，然后以1C的电流恒流充电至4.48V，然后4.48V恒压充电至0.02C，最后静置5min，拆解观察负极极耳凹槽和负极端部的析锂程度。
其中，未发现析锂或析锂面积<10％在此称为不析锂；析锂面积≥10％称为析锂。
粘结力测试：
将每个实施例的打孔胶纸和对比例中的胶纸分别粘贴于铝箔上，裁切为20mm×60mm的条状样品，在温度为85℃、压力为1MPa的条件下热压处理40min，然后在85℃电解液中浸泡4h后，将样品通过双面胶(日东5000NS)粘贴于钢板上(粘附长度不低于40mm)，并将钢板固定在高铁拉力机的相应位置，拉起试样未被粘附在钢板上的另一端，将样品放入夹头内夹紧，其中被拉起的样品部分与钢板在空间上夹角为180°，夹头以50mm/min的速度拉动，最终测得平稳区域的拉力平均值记为浸泡电解液后的粘结力。
其中，电解液的有机溶剂为碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸二乙酯(DEC)、丙酸乙酯(EP)，且质量比EC:PC:DEC:EP＝3:1:3:3，溶质为六氟磷酸锂(LiPF 6)，LiPF 6的浓度为1mol/L。
溢胶测试：
测量胶纸的初始宽度，然后将胶纸在温度为85℃、压力为1MPa下热压处理1h后测量胶纸的最大宽度为溢胶宽度。每个实施例中的打孔胶纸和对比例中的胶纸测试10个样品，胶纸的单边最大溢胶宽度为10个样品的溢胶宽度与初始宽度之差的平均值的二分之一。
溶胀厚度测试：
将胶纸裁切为20mm×60mm的条状，测量胶纸的初始厚度记为B，然后将胶纸贴于铝箔上，在电解液中浸泡24h，浸泡温度为85℃，浸泡完成后取出擦干，在5min内使用万分尺测量胶纸边缘的厚度记为A。随机选取10个地方进行测量，得到的平均值为胶纸溶胀厚度A-B。每个实施例中的打孔胶纸和对比例中的胶纸测试10个样品，胶纸的溶胀厚度为10个样品A-B的平均值。其中，电解液与上述粘结力测试中的电解液相同。
实施例1-1
<正极的制备>
将正极活性材料钴酸锂(LiCoO 2、导电剂导电炭黑(Super P)、粘结剂聚偏二氟乙烯按照质量比为97∶1.4∶1.6进行混合，加入N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌均匀，获得正极浆料，其中正极浆料的固含量为75wt％。将正极浆料均匀涂覆于厚度为9μm的正极集流体铝箔的一个表面上，将铝箔在85℃下烘干，得到涂层厚度为110μm的单面涂覆有正极活性物质层的正极。在铝箔的另一个表面上重复以上步骤，即得到双面涂布正极活性材料的正极。然后经过冷压、裁片、分切后，在85℃的真空条件下干燥8h，得到规格为74mm×851mm的正极。其中，正极包括一个正极极耳，在本申请中，如图2所示，绿胶粘贴在如下位置：(1)正极极耳与正极的连接的连接区域；(2)正极极耳所在的正极相邻的两个负极靠近正极的表面，且粘贴位置与上述连接区域位置对应。其中，绿胶购自于东莞澳中新材料科技股份有限公司。
<负极的制备>
将负极活性材料人造石墨、导电剂Super P、增稠剂羧甲基纤维素钠(CMC-Na)、粘结剂丁苯橡胶(SBR)按照质量比为96.4∶1.5∶0.5∶1.6进行混合，加入去离子水，在真空搅拌机作用下搅拌均匀，获得负极浆料，其中负极浆料的固含量为70wt％。将负极浆料均匀涂覆于厚度为6μm的负极集流体铜箔的一个表面上，将铜箔在110℃下烘干，得到涂层厚度为130μm的单面涂覆有负极活性物质层的负极。在铝箔的另一个表面上重复以上步骤，即得到双面涂布负极活性材料的负极。然后经过冷压、裁片、分切后，在120℃的真空条 件下干燥12h，得到规格为76mm×867mm的负极。其中，负极包括一个负极极耳。并通过激光清洗设置负极极耳凹槽。
<电解液的制备>
在含水量<10ppm的氩气气氛手套箱中，将碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、丙酸乙酯(EP)按质量比1∶1∶1均匀混合，形成基础溶剂，最后加入LiPF 6溶解并搅拌均匀，形成电解液，基于电解液的总质量，LiPF 6的质量百分含量为12.5％，余量为基础溶剂。
<隔膜的制备>
以聚乙烯多孔聚合物薄膜作为隔膜。
<胶纸的制备>
胶纸包括设置在基材层一个表面的胶层，其中，胶纸的厚度为24μm，胶层的厚度为12μm，基材层厚度为12μm。
将聚丙烯、弹性体聚氨酯、填料钛白粉、抗氧剂二苯胺按照质量比为60∶25∶7.5∶7.5混合均匀，然后涂覆在基材层上在120℃下烘干得到胶纸，进一步使用激光打孔的方法，按照孔间距b＝0.6mm，孔直径c＝0.8mm，在打孔胶纸长度方向边缘两侧打孔。其中，聚丙烯的分子量为115000，第一打孔区宽度为8mm，第二打孔区宽度为8mm，非打孔区宽度为9mm，孔的形状为圆形。
基材层为聚对苯二甲酸乙二醇酯薄膜。
<锂离子电池的制备>
将25mm×45mm的胶纸粘贴于负极极耳凹槽表面，以及正极的第一表面和第二表面且绕过正极的端部，粘贴位置与负极极耳凹槽位置相对。然后将正极、隔膜、负极按顺序叠好，使隔膜处于正极和负极中间起到隔离的作用，卷绕得到电极组件。将电极组件置于铝塑膜包装袋中，干燥后注入电解液，经过真空封装、静置、化成、容量、脱气、切边等工序得到锂离子电池。其中，化成条件是以0.02C恒流充电到3.3V，再以0.1C恒流充电到3.6V，最后以0.2C恒流充电到4.45V。
实施例1-2至实施例1-4
除了按照表1调整打孔胶纸的粘贴位置以外，其余与实施例1-1相同。
实施例2-1至实施例2-8
除了按照表2调整打孔胶纸的宽度w 1，以及打孔胶纸中第一打孔区的宽度w 2、第二打孔区的宽度w 3、非打孔区的宽度w 4、孔间距b、孔直径c、孔形状以外，其余与实施例 1-3相同。
实施例3-1至实施例3-7
除了按照表4调整胶层成分1的组分及其重均分子量以外，其余与实施例1-3相同。
实施例4-1至实施例4-7
除了按照表5调整胶层成分1的质量百分含量、胶层成分2的组成及各组分质量百分含量以外，其余与实施例1-3相同。
实施例5-1至实施例5-6
除了按照表6调整胶层和基材层的厚度，以及基材层材料以外，其余与实施例1-3相同。
对比例1
除了采用绿胶代替打孔胶纸以外，其余与实施例1-1相同。
各实施例及对比例的制备参数和性能测试如表1至表6所示。
表1
Figure PCTCN2022080958-appb-000001
注：表1中，“/”表示不存在相应制备参数。
从实施例1-1至实施例1-4以及对比例1可以看出，本申请实施例中的锂离子电池包含打孔胶纸，可以有效改善电锂离子电池的析锂问题。打孔胶纸的粘贴位置通常会影响到电化学装置的性能，从实施例1-1至实施例1-4可以看出，通过将打孔胶纸粘贴在在本申请范围内的位置，可以有效改善锂离子电池的析锂问题。
表2
Figure PCTCN2022080958-appb-000002
注：表2中，“/”表示不存在相应的制备参数。
表3
Figure PCTCN2022080958-appb-000003
打孔胶纸的宽度w 1、第一打孔区的宽度w 2、第二打孔区的宽度w 3、非打孔区的宽度w 4、第二打孔区与非打孔区宽度的比例w 3∶w 4，以及孔间距b、孔直径c和孔的形状通常也会影响到电化学装置的性能，从实施例1-3、实施例2-1至实施例2-8中可以看出，通过调控上述参数在本申请的范围内，得到的打孔胶纸具有较高的粘结力以及较低的溶胀厚度和单边最大溢胶宽度，同时将打孔胶纸粘贴在本申请范围内的位置，能够改善电化学装置的析锂问题。此外，从实施例1-3、实施例2-7和实施例2-8中可以看出，当第一打孔区中孔的面积的总和占第一打孔区的面积的比例或者第二打孔区中孔的面积的总和占第二打孔区的面积的比例过大时，打孔胶纸的粘结力明显下降，但由于锂离子可以更好地传输，因 此能够改善电化学装置的析锂问题；但是当第一打孔区中孔的面积的总和占第一打孔区的孔面积的比例或者第二打孔区中孔的面积的总和占第二打孔区的面积的比例过小时，影响锂离子的传输，从而无法改善电化学装置的析锂问题。通过调控第一打孔区中孔的面积的总和占第一打孔区的面积的比例以及第二打孔区中孔的面积的总和占第二打孔区的面积的比例在本申请的范围内，能够改善电化学装置的析锂问题。
表4
Figure PCTCN2022080958-appb-000004
打孔胶纸的胶层聚烯烃和/或改性聚烯烃的种类及其重均分子量也会打孔胶纸的性能和影响到电化学装置的性能，从实施例1-3、实施例3-1至实施例3-7中可以看出，选择在本申请范围内的胶层组分制作的打孔胶纸，得到的打孔胶纸具有较高的粘结力以及较低的溶胀厚度和单边最大溢胶宽度，同时将打孔胶纸粘贴在本申请范围内的位置，能够改善电化学装置的析锂问题，也有利于改善电化学装置的安全性能。此外，从实施例1-3、实施例3-1至实施例3-4中可以看出，当聚烯烃的分子量在本申请的范围时，打孔胶纸具有良好的粘结力和较低的溶胀厚度，从而能够改善电化学装置的析锂问题。
表5
Figure PCTCN2022080958-appb-000005
Figure PCTCN2022080958-appb-000006
打孔胶纸胶层中聚烯烃和/或改性聚烯烃的含量，弹性体、填料、抗氧剂的种类及含量也会影响到打孔胶纸的性能和电化学装置的性能，从实施例1-3、实施例4-1至实施例4-7中可以看出，选择在本申请范围内的胶层组分制作打孔胶纸，得到的打孔胶纸具有较高的粘结力以及较低的溶胀厚度和单边最大溢胶宽度，同时将打孔胶纸粘贴在本申请范围内的位置，能够提高电化学装置的安全性能，改善电化学装置的析锂问题。
表6
Figure PCTCN2022080958-appb-000007
打孔胶纸胶层的厚度、基材层的种类及厚度也会影响到打孔胶纸的性能和电化学装置的性能，从实施例1-3、实施例5-1至实施例5-6可以看出，选择在本申请范围内的胶层和基材层制作打孔胶纸，得到的打孔胶纸具有较高的粘结力以及较低的溶胀厚度和单边最大溢胶宽度，同时将打孔胶纸粘贴在本申请范围内的位置，能够改善电化学装置的析锂问题。
需要说明的是，在本文中，诸如第一和第二等之类的关系术语仅仅用来将一个实体或操作与另一个实体或操作区分开来，而不一定要求或者暗示这些实体或操作之间存在任何这种实际的关系或者顺序。而且，术语“包括”、“包含”或者其任何其它变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者设备不仅包括那些要素，而且还包括没有明确列出的其它要素，或者是还包括为这种过程、方法、物品或者设备所固有的要素。
本说明书中的各个实施方案均采用相关的方式描述，各个实施方案之间相同相似的部分互相参见即可，每个实施方案重点说明的都是与其它实施例的不同之处。
以上所述仅为本申请的较佳实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本申请保护的范围之内。

Claims (14)

  1. 一种电化学装置，其包括电极组件，所述电极组件包括正极、负极和隔膜，所述隔膜设置于相邻的所述正极和所述负极之间；
    所述负极包括负极集流体和设置在所述负极集流体至少一个表面的负极活性物质层，所述负极中设置有露出所述负极集流体的负极极耳凹槽，负极极耳固定在所述负极极耳凹槽中并与所述负极集流体电连接；
    其中，所述负极极耳表面设置有打孔胶纸，所述打孔胶纸沿长度方向的边缘设置有孔，所述打孔胶纸的孔位于所述打孔胶纸中覆盖所述负极极耳凹槽两侧所述负极活性物质层的部分。
  2. 根据权利要求1所述的电化学装置，其中，所述正极包括相对的第一表面和第二表面，所述第一表面靠近所述负极；
    所述打孔胶纸还粘贴在所述第一表面与所述负极极耳凹槽相对应的位置上。
  3. 根据权利要求2所述的电化学装置，其中，所述打孔胶纸还粘贴在所述第二表面与所述负极极耳凹槽相对应的位置上。
  4. 根据权利要求2所述的电化学装置，其中，所述打孔胶纸绕过所述正极端部边缘还粘贴在所述第二表面与所述负极极耳凹槽相对应的位置上。
  5. 根据权利要求1所述的电化学装置，其中，沿所述打孔胶纸的宽度方向设置有第一打孔区、第二打孔区和非打孔区，所述非打孔区位于所述第一打孔区和所述第二打孔区之间，所述打孔胶纸的宽度w 1为6mm至30mm；所述第一打孔区的宽度为w 2，所述第二打孔区的宽度为w 3，w 2和w 3各自独立地选自1mm至10mm；所述非打孔区的宽度w 4为2mm至10mm，所述第一打孔区的宽度或所述第二打孔区的宽度与所述非打孔区的宽度比为0.5∶1至1∶1。
  6. 根据权利要求5所述的电化学装置，其中，所述打孔胶纸的孔满足如下特征中的至少一者：
    (1)所述孔的间距b为0.1mm至2mm，所述孔的轮廓的外接圆最小直径c为0.1mm至2mm；
    (2)所述第一打孔区中孔的面积的总和占所述第一打孔区的面积的比例为20％至80％， 所述第二打孔区中孔的面积的总和占所述第二打孔区的面积的比例为20％至80％；
    (3)所述孔的形状为圆形、椭圆形或多边形中的至少一种。
  7. 根据权利要求1所述的电化学装置，其中，所述打孔胶纸包括胶层和基材层，所述胶层包含聚烯烃和/或改性聚烯烃，以及弹性体、填料和抗氧剂，基于所述胶层的总质量，所述聚烯烃和/或改性聚烯烃的质量百分含量为45％至85％，所述弹性体的质量百分含量为10％至35％，所述填料的质量百分含量为2％至10％，所述抗氧剂的质量百分含量为2％至10％。
  8. 根据权利要求7所述的电化学装置，其中，所述胶层满足如下特征中的至少一者：
    (1)所述聚烯烃包括聚乙烯和/或聚丙烯，所述改性聚烯烃包括马来酸酐改性聚乙烯和/或马来酸酐改性聚丙烯，所述聚烯烃和改性聚烯烃的重均分子量各自独立地选自30000至200000；
    (2)所述弹性体包括苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物、聚氨酯、聚酰胺、聚丁二烯或聚异丁烯中的至少一种；
    (3)所述填料包括钛白粉、滑石粉、白炭黑或碳酸钙中的至少一种；
    (4)所述抗氧剂包括二苯胺、亚磷酸三甲酯、亚磷酸三乙酯或硫代二丙酸双十八醇酯中的至少一种。
  9. 根据权利要求7所述的电化学装置，其中，所述基材层包括聚对苯二甲酸乙二醇酯、聚酰亚胺或聚丙烯中的至少一种。
  10. 根据权利要求7所述的电化学装置，其中，所述胶层的厚度为4μm至20μm，所述基材层的厚度为4μm至30μm。
  11. 根据权利要求1所述的电化学装置，其中，所述打孔胶纸在85℃电解液中浸泡4h后的粘结力为0.2N/mm至0.5N/mm。
  12. 根据权利要求1所述的电化学装置，其中，所述打孔胶纸在85℃电解液中浸泡24h的厚度A与未经所述电解液浸泡的厚度B满足：0μm<A-B≤2μm。
  13. 根据权利要求1所述的电化学装置，其中，所述打孔胶纸的单边最大溢胶宽度为0mm至1mm。
  14. 一种电子装置，其包含权利要求1至13中任一项所述的电化学装置。
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