Gummed paper and electrochemical device and electronic device comprising same

Abstract

The invention provides gummed paper and an electrochemical device and an electronic device comprising the gummed paper, the gummed paper comprises a gummed layer and a base material layer, the gummed layer comprises polyolefin and / or modified polyolefin, the number of reaction peaks of the gummed paper in a lithium-salt-free electrolyte is zero when the scanning voltage is 4.5 V through cyclic voltammetry testing, and the number of the reaction peaks is zero when the scanning voltage is 4.5 V; and the oxidation peak intensity at the scanning voltage between 3V and 4.5 V is less than 1 * 10 <-7 > A. The gummed paper provided by the invention has good electrolyte resistance, high binding power and low swelling degree, so that the safety performance of the electrochemical device is improved, and the service life of the electrochemical device is prolonged.

Description

[0001] This application is a divisional application with application number 202180025456.1, application date September 26, 2021, and invention name “Adhesive tape and electrochemical device and electronic device containing the adhesive tape”. Technical Field

[0002] The present application relates to the field of electrochemistry, and in particular to an adhesive tape and an electrochemical device and an electronic device comprising the adhesive tape. Background Art

[0003] In the production and manufacturing process of lithium-ion batteries, adhesive tape is needed to insulate and fix lithium-ion batteries. At present, special adhesive tape for lithium-ion batteries is generally based on polyethylene terephthalate (PET) as the base material and polyacrylate as the adhesive layer. However, due to the poor electrolyte resistance of polyacrylate, its adhesion is weak after soaking in electrolyte. When used as a tab protective adhesive, it cannot effectively restrain the tab, resulting in the adhesive tape offset phenomenon in the welding area between the tab and the pole piece, and the welding area is easy to be torn. At the same time, when used as a tail glue for the tail of a lithium-ion battery, its own swelling bulge can easily lead to a poor appearance of the battery, and this phenomenon will become more obvious as the voltage increases, affecting the safety performance of the lithium-ion battery. Summary of the invention

[0004] The present application provides an adhesive tape and an electrochemical device and an electronic device comprising the adhesive tape, so as to improve the safety of the electrochemical device.

[0005] It should be noted that in the content of this application, lithium-ion batteries are used as an example of electrochemical devices to explain this application, but the electrochemical devices of this application are not limited to lithium-ion batteries. The specific technical solution is as follows:

[0006] The first aspect of the present application provides a rubber tape, comprising a substrate layer and a rubber layer disposed on one surface of the substrate layer, wherein the rubber layer comprises polyolefin and / or modified polyolefin, and the dissolution of the rubber tape in a lithium salt-free electrolyte is tested by cyclic voltammetry, and the number of reaction peaks is zero when the scanning voltage is 4.5V, and the oxidation peak intensity between the scanning voltage of 3V and 4.5V is less than 1×10 -7 A.

[0007] The lithium salt-free electrolyte is a mixed solvent including ethylene carbonate, propylene carbonate, diethyl carbonate and ethyl propionate in a mass ratio of 3:1:3:3.

[0008] Without being limited to any theory, when the adhesive layer includes polyolefin and / or modified polyolefin, and the dissolution of the adhesive paper in the lithium salt-free electrolyte is tested by cyclic voltammetry, the number of reaction peaks is zero when the scanning voltage is 4.5V, and the oxidation peak intensity between the scanning voltage of 3V and 4.5V is less than 1×10 -7A, the electrolyte resistance and adhesion of the obtained adhesive tape are improved, and the swelling degree is reduced. After the adhesive tape is soaked in the lithium salt-free electrolyte, the dissolution in the lithium salt-free electrolyte is tested. When the scanning voltage is 4.5V, the number of reaction peaks is zero, which shows that the adhesive tape is suitable for high voltage system. The oxidation peak intensity between the scanning voltage of 3V and 4.5V is less than 1×10 -7 A, which shows that the adhesive tape has high electrochemical stability in lithium-free electrolyte and no electrochemical risk. That is, the adhesive tape has good electrolyte resistance, high adhesion and low swelling. Specifically, after being soaked in lithium-free electrolyte, the adhesive tape can still effectively restrain the pole ear, so that the welding area between the pole ear and the pole piece is not easy to be offset, and the welding area is not easy to be torn; after being soaked in lithium-free electrolyte for a long time at high temperature, the thickness of the adhesive tape changes little, which can ensure that the electrochemical device has no protrusions on its appearance after high-temperature storage, which is beneficial to improve the safety performance of the electrochemical device and extend the service life of the electrochemical device. In this application, the dissolution refers to the interaction force between the electrolyte molecules and the glue layer molecules when the glue layer contacts the electrolyte. This force is greater than the cohesive force between the glue layer molecules, so that the glue layer molecules are separated from each other and dissolved in the electrolyte. For example, the dissolution may include but is not limited to small molecules, oligomers or CC short chains. The aforementioned high temperature refers to a temperature greater than or equal to 40°C.

[0009] In some embodiments of the present application, the polyolefin includes polyethylene and / or polypropylene, and the modified polyolefin includes maleic anhydride-modified polyethylene and / or maleic anhydride-modified polypropylene. Without being limited to any theory, by selecting the above polyolefin and modified polyolefin, it is beneficial to improve the electrolyte resistance of the adhesive tape, thereby improving the safety performance of the electrochemical device.

[0010] In some embodiments of the present application, the weight average molecular weight of the polyolefin and / or modified polyolefin is 50000 to 400000. For example, the weight average molecular weight of the polyolefin and / or modified polyolefin can be 50000, 100000, 150000, 200000, 250000, 300000, 350000, 400000 or any range therebetween. Without being limited to any theory, by regulating the molecular weight of the polyolefin and modified polyolefin within the above range, it is beneficial to improve the bonding force of the adhesive tape, thereby improving the safety performance of the electrochemical device.

[0011] In some embodiments of the present application, based on the mass of the adhesive layer, the mass percentage of the polyolefin and / or modified polyolefin is 45% to 85%. For example, the mass percentage of the polyolefin and / or modified polyolefin can be 45%, 50%, 60%, 70%, 80%, 85% or any range therebetween. Without being limited to any theory, when the mass percentage of the polyolefin and / or modified polyolefin is too low (e.g., less than 45%), the improvement of the electrolyte resistance, adhesion and swelling performance of the adhesive tape is not obvious, and thus the improvement effect on the safety performance and service life of the electrochemical device is not obvious. When the mass percentage of the polyolefin and / or modified polyolefin is too high (e.g., greater than 85%), the flexibility of the adhesive layer will be deteriorated, and the polyolefin and / or modified polyolefin will be wasted, resulting in an increase in the cost of the electrochemical device. By selecting the above-mentioned polyolefin and / or modified polyolefin and adjusting its mass percentage within the above-mentioned range, it is beneficial to improve the electrolyte resistance, adhesion and swelling degree of the adhesive tape, thereby improving the safety performance of the electrochemical device, extending the service life of the electrochemical device and controlling the cost.

[0012] In some embodiments of the present application, the adhesive layer may also include a thermoplastic elastomer, which includes at least one of styrene-ethylene-butylene-styrene block copolymer, polyurethane, polyolefin or polyamide. Preferably, the polyolefin includes polyisobutylene and / or polybutadiene. Based on the mass of the adhesive layer, the mass percentage of the thermoplastic elastomer is 10% to 35%. For example, the mass percentage of the thermoplastic elastomer can be 10%, 15%, 20%, 25%, 30%, 35% or any range therebetween. Without being limited to any theory, a thermoplastic elastomer refers to a polymer material that shows rubber elasticity at room temperature and can be plasticized and formed at high temperature. It can ensure the bonding force of the adhesive tape and further improve the electrolyte resistance of the adhesive tape. When the mass percentage of the added thermoplastic elastomer is too low (e.g., less than 10%), the performance of the adhesive tape is not significantly improved; when the mass percentage of the added thermoplastic elastomer is too high (e.g., greater than 35%), the mass percentage of the polyolefin and / or modified polyolefin decreases, resulting in a decrease in the electrolyte resistance and adhesion of the adhesive tape. By selecting the above thermoplastic elastomer and regulating its mass percentage within the above range, it is beneficial to improve the electrolyte resistance and adhesion of the adhesive tape, thereby improving the safety performance of the electrochemical device and extending the service life of the electrochemical device.

[0013] In some embodiments of the present application, the adhesive layer may further include petroleum resin. The petroleum resin includes at least one of aliphatic resin (C5), aromatic resin (C9), or aliphatic / aromatic copolymer resin (C5 / C9). Based on the mass of the adhesive layer, the mass percentage content of the petroleum resin is 2% to 5%. For example, the mass percentage content of the petroleum resin may be 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any range therebetween. Without being limited to any theory, the petroleum resin provided in the present application has a relatively high glass transition temperature. By selecting the above petroleum resin and controlling its mass percentage content within the above range, the adhesion of the adhesive tape can be improved, which is beneficial to extending the service life of the electrochemical device. The present application does not particularly limit the weight-average molecular weight of the petroleum resin, as long as the object of the present application can be achieved. For example, the weight-average molecular weight is 500 to 10,000.

[0014] In some embodiments of the present application, the adhesive layer may further include a filler. The filler includes at least one of titanium dioxide, talc, silica, or calcium carbonate. Based on the mass of the adhesive layer, the mass percentage content of the filler is 2% to 5%. For example, the mass percentage content of the filler may be 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any range therebetween. Without being limited to any theory, by selecting the above filler and controlling the mass percentage content of the filler within the above range, it is beneficial to improve the electrolyte resistance performance of the adhesive tape, thereby improving the safety performance of the electrochemical device and extending the service life of the electrochemical device.

[0015] In some embodiments of the present application, the adhesive layer may further include an antioxidant. The antioxidant includes at least one of diphenylamine, phosphite triester, or distearyl thiodipropionate. Based on the mass of the adhesive layer, the mass percentage content of the antioxidant is 2% to 5%. For example, the mass percentage content of the antioxidant may be 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any range therebetween. Without being limited to any theory, by selecting the above antioxidant and controlling the mass percentage content of the antioxidant within the above range, it is beneficial to improve the electrolyte resistance performance of the adhesive tape, thereby improving the safety performance of the electrochemical device and extending the service life of the electrochemical device.

[0016] In some embodiments of the present application, the thickness of the adhesive layer is 4 μm to 20 μm, preferably 8 μm to 15 μm. For example, the thickness of the adhesive layer is 4 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm or any range therebetween. Without being limited to any theory, when the thickness of the adhesive layer is too small (for example, less than 4 μm), it is more likely to change in performance during long-term contact with the electrolyte, affecting the performance of the adhesive paper, thereby affecting the service life of the electrochemical device. As the thickness of the adhesive layer increases, the adhesive force of the adhesive layer shows a trend of gradually increasing, but the effect of thickness on the adhesive force is limited. When the thickness of the adhesive layer is too large (for example, greater than 20 μm), the adhesive force of the adhesive layer tends to remain unchanged, but the energy density of the electrochemical device will be reduced. By regulating the thickness of the adhesive layer within the above range, it is beneficial to extend the service life of the electrochemical device and increase the energy density of the electrochemical device.

[0017] In some embodiments of the present application, the adhesive layer has an adhesive force of 0.2N / mm to 1N / mm after hot pressing, that is, the adhesive tape provided in the present application has a high adhesive force, which is conducive to extending the service life of the electrochemical device. For example, the adhesive force after hot pressing is 0.2N / mm, 0.3N / mm, 0.4N / mm, 0.5N / mm, 0.8N / mm, 1N / mm or any range therebetween. In the present application, hot pressing refers to hot pressing treatment for 10min to 120min at a temperature of 60°C to 100°C and a pressure of 0.3MPa to 2MPa.

[0018] In some embodiments of the present application, the adhesive force of the adhesive layer after being immersed in an electrolyte at 85°C for 4 hours is 0.1N / mm to 1N / mm, that is, the adhesive tape provided in the present application has good electrolyte resistance at high temperatures, which is beneficial to improving the safety performance of the electrochemical device and extending the service life of the electrochemical device. For example, the adhesive force of the adhesive tape after being immersed in an electrolyte at 85°C for 4 hours after hot pressing can be 0.1N / mm, 0.2N / mm, 0.3N / mm, 0.4N / mm, 0.5N / mm, 0.8N / mm, 1N / mm or any range therebetween. Among them, the adhesive force test of the adhesive tape after being immersed in an electrolyte at 85°C for 4 hours is to first hot press the adhesive tape and then immerse it in the electrolyte, and then test its adhesive force.

[0019] In some embodiments of the present application, the thickness A of the adhesive tape after being immersed in an electrolyte at 85°C for 24 hours and the thickness B without being immersed in the electrolyte satisfy: 0μm<AB≤2μm, that is, the swelling degree of the adhesive tape provided in the present application is low, which is beneficial to improving the safety performance of the electrochemical device and extending the service life of the electrochemical device. For example, the value of AB can be 0μm, 0.5μm, 1μm, 1.5μm, 2μm or any range therebetween.

[0020] In some embodiments of the present application, after the adhesive tape is immersed in an electrolyte at 85°C for 12 hours, the turbidity D of the electrolyte is compared with the turbidity E of the electrolyte before immersion using the Pantone international standard colorimetric card. The relationship is 100C<DE≤1535C, that is, the adhesive tape provided in the present application has good electrolyte resistance, which is beneficial to improving the safety performance of the electrochemical device and extending the service life of the electrochemical device.

[0021] In some embodiments of the present application, the maximum glue overflow width of the adhesive tape is 0mm to 1mm, that is, the adhesive tape provided in the present application has good thermal stability, which is beneficial to improving the safety performance of the electrochemical device. For example, the maximum glue overflow width of the adhesive tape can be 0mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm or any range therebetween. In the present application, the maximum glue overflow width of the adhesive tape refers to the difference between the maximum width of the adhesive tape after the adhesive tape is hot-pressed at a temperature of 85°C and a pressure of 1MPa to 2MPa for 1h and the width of the adhesive tape that has not been hot-pressed.

[0022] In some embodiments of the present application, the substrate layer includes at least one of polyethylene terephthalate, polyimide or polypropylene, and the thickness of the substrate layer is 4 μm to 40 μm. For example, the thickness of the substrate layer can be 4 μm, 5 μm, 10 μm, 12 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm or any range therebetween. When the thickness of the substrate layer is too small (for example, less than 4 μm), the supporting effect on the adhesive layer is weak, and at the same time, the insulation protection and fixing effect of the lithium-ion battery are deteriorated. When the thickness of the substrate layer is too large (for example, greater than 40 μm), the effect is equivalent to the embodiment within the preferred range, but the energy density of the electrochemical device will be reduced. Without being limited to any theory, by selecting the material of the above-mentioned substrate layer and regulating the thickness of the substrate layer within the above-mentioned range, it is beneficial to improve the electrolyte resistance of the adhesive paper, thereby improving the safety performance of the electrochemical device and extending the service life of the electrochemical device.

[0023] In some embodiments of the present application, the thickness of the adhesive tape is 8 μm to 60 μm, preferably 12 μm to 40 μm. In the present application, the thickness of the adhesive tape refers to the sum of the thickness of the adhesive layer and the thickness of the substrate layer.

[0024] In some embodiments of the present application, the adhesive tape further includes a release paper, which is disposed on the surface of the adhesive layer facing away from the substrate layer. The provision of the release paper in the adhesive tape is used 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 adhesive tape. Those skilled in the art can select any suitable release paper material or size in the art according to actual needs. In some embodiments, 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 substrate layer or the surface of the side of the adhesive layer. In some embodiments, the release paper is torn off before the adhesive layer in the adhesive tape is attached to the target surface. In some embodiments, the release paper comprises a single-sided silicone release film or a double-sided silicone release film.

[0025] The present application has no particular restrictions on the preparation method of the adhesive tape, as long as the purpose of the present application can be achieved. For example, the present application may adopt the following method for preparing the adhesive tape, which includes the following steps: mixing the raw materials of the adhesive layer in a certain proportion to obtain an adhesive layer slurry, then coating the adhesive layer slurry on the substrate layer using a coating machine, and drying to obtain the adhesive tape. Among them, the substrate layer can be treated with a non-silicon release agent first and then the surface can be corona treated, and the drying temperature can be 60°C to 120°C.

[0026] A second aspect of the present application provides an electrochemical device, comprising the adhesive tape in any embodiment of the present application, and the obtained electrochemical device has good electrolyte resistance and a long service life.

[0027] In some embodiments of the present application, a pole piece is also included, and the pole piece includes a pole ear. The bonding force between the adhesive layer in the adhesive paper and the pole ear or between the adhesive layer in the adhesive paper and the pole piece is 0.2N / mm to 1.0N / mm, which is conducive to improving the safety performance of the electrochemical device and extending the service life of the electrochemical device. For example, the bonding force between the adhesive layer and the pole ear or between the adhesive paper and the pole piece can be 0.2N / mm, 0.3N / mm, 0.4N / mm, 0.5N / mm, 0.8N / mm, 1N / mm or any range therebetween. Among them, the pole piece can be a positive pole piece or a negative pole piece. In the present application, the pole ear refers to a metal conductor drawn from the pole piece, which is used to connect other parts of the electrochemical device in series or in parallel. The pole ear of the positive pole piece is the positive pole ear, and the pole ear of the negative pole piece is the negative pole ear. The present application has no special restrictions on the material of the pole ear, as long as the purpose of the present application can be achieved, for example, the pole ear material known in the art is used.

[0028] There is no particular restriction on the positive electrode sheet in this application, as long as the purpose of this application can be achieved. For example, the positive electrode sheet generally includes a positive electrode current collector and a positive electrode material layer. Among them, there is no particular restriction on the positive electrode current collector, as long as the purpose of this application can be achieved, for example, it may include but is not limited to aluminum foil, aluminum alloy foil or composite current collector. In this application, 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 8μm to 12μm.

[0029] In the present application, the positive electrode material layer includes a positive electrode active material, wherein the positive electrode active material is not particularly limited, as long as the purpose of the present application can be achieved, for example, it may include at least one of a composite oxide of lithium and a transition metal element. The present application has no particular restrictions on the above-mentioned transition metal elements, as long as the purpose of the present application can be achieved, for example, it may include at least one of nickel, manganese, cobalt or iron. Specifically, the positive electrode active material may include at least one of lithium nickel cobalt manganese oxide (811, 622, 523, 111), lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium-rich manganese-based materials, lithium cobalt oxide, lithium manganese oxide, lithium iron manganese phosphate or lithium titanate.

[0030] In the present application, the positive electrode material layer may also include a conductive agent, and the present application has no particular restrictions on the conductive agent, as long as the purpose of the present application can be achieved, for example, it may include but is not limited to at least one of conductive carbon black (Super P), carbon nanotubes (CNTs), carbon fibers, flake graphite, Ketjen black, graphene, metal 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 nano-carbon fibers. The above-mentioned metal materials may include but are not limited to metal powders and / or metal fibers, and specifically, the metal may include but is not limited to at least one of copper, nickel, aluminum or silver. The above-mentioned conductive polymers may include but are not limited to at least one of polyphenylene derivatives, polyaniline, polythiophene, polyacetylene or polypyrrole.

[0031] In the present application, the positive electrode material layer may also include a binder. There is no particular limitation on the binder as long as the purpose of the present application can be achieved. For example, it may include but is not limited to at least one of polyacrylic acid, sodium polyacrylate, potassium polyacrylate, lithium polyacrylate, polyimide, polyvinyl alcohol, carboxymethyl cellulose, sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, polyimide, polyamide-imide, styrene-butadiene rubber or polyvinylidene fluoride.

[0032] Optionally, the positive electrode sheet may further include a conductive layer, which is located between the positive current collector and the positive electrode material layer. The present application has no particular limitation on the composition of the conductive layer, which may be a commonly used conductive layer in the art, for example, including but not limited to the above conductive agent and the above binder.

[0033] There is no special restriction on the negative electrode sheet in this application, as long as the purpose of this application can be achieved. For example, the negative electrode sheet usually includes a negative electrode current collector and a negative electrode material layer. Among them, there is no special restriction on the negative electrode current collector, as long as the purpose of this application can be achieved, for example, it may include but is not limited to copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, foam nickel, foam copper or composite current collector, etc. In this application, there is no special restriction on the thickness of the negative electrode current collector, as long as the purpose of this application can be achieved, for example, the thickness is 4μm to 12μm.

[0034] In the present application, the negative electrode material layer includes a negative electrode active material, wherein the negative electrode active material is not particularly limited, as long as the purpose of the present application can be achieved, for example, it may include but is not limited to natural graphite, artificial graphite, mesophase microcarbon beads, hard carbon, soft carbon, silicon, silicon-carbon composite, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO 2 , spinel-structured lithiated TiO 2 -Li 4 Ti 5 O 12 Or at least one of Li-Al alloy.

[0035] In the present application, the negative electrode material layer may further include a conductive agent. The present application has no particular limitation on the conductive agent, as long as the purpose of the present application can be achieved. For example, it may include but is not limited to at least one of the above conductive agents.

[0036] In the present application, the negative electrode material layer may further include a binder. The present application has no particular limitation on the binder, as long as the purpose of the present application can be achieved. For example, it may include but is not limited to at least one of the above-mentioned binders.

[0037] Optionally, the negative electrode sheet may further include a conductive layer, which is located between the negative electrode current collector and the negative electrode material layer. The present application has no particular limitation on the composition of the conductive layer, which may be a commonly used conductive layer in the art, and may include but is not limited to the above conductive agent and the above binder.

[0038] The electrochemical device of the present application also includes an isolating membrane. The present application has no special restrictions on the isolating membrane, as long as the purpose of the present application can be achieved. For example, it may include but is not limited to polyethylene (PE), polypropylene (PP), polytetrafluoroethylene-based polyolefin (PO)-type membranes, polyester membranes (such as polyethylene terephthalate (PET) membranes), cellulose membranes, polyimide membranes (PI), polyamide membranes (PA), spandex, aramid membranes, woven membranes, non-woven membranes (non-woven fabrics), microporous membranes, composite membranes, diaphragm paper, rolled membranes or spinning membranes. At least one of the isolating membrane of the present application may have a porous structure, and the size of the pore size is not particularly limited, as long as the purpose of the present application can be achieved. For example, the size of the pore size can be 0.01μm to 1μm. In the present application, the thickness of the isolating membrane is not particularly limited, as long as the purpose of the present application can be achieved. For example, the thickness can be 5μm to 500μm.

[0039] For example, the isolation membrane may include an isolation membrane substrate layer and a surface treatment layer. The isolation membrane substrate layer may be a non-woven fabric, a film or a composite film having a porous structure, and the material of the isolation membrane substrate layer may include but is not limited to at least one of polyethylene, polypropylene, polyethylene terephthalate or polyimide. Optionally, a polypropylene porous film, a polyethylene porous film, a polypropylene non-woven fabric, a polyethylene non-woven fabric or a polypropylene-polyethylene-polypropylene porous composite film may be used. Optionally, a surface treatment layer is provided on at least one surface of the isolation membrane substrate layer, and the surface treatment layer may be a polymer layer or an inorganic layer, or a layer formed by a mixed polymer and an inorganic substance.

[0040] The polymer layer contains polymers, and the material of the polymer may include but is not limited to at least one of polypropylene, polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylic acid salt, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride or poly (vinylidene fluoride-hexafluoropropylene). The inorganic layer may include but is not limited to inorganic particles and binders. The present application has no particular restrictions on inorganic particles. For example, it may include but is not limited to at least one of ceramics, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide or barium sulfate. The present application has no particular restrictions on the binder in the inorganic layer. For example, it may include but is not limited to at least one of polyvinylidene fluoride, copolymer of vinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylic acid ester, polyacrylic acid, polyacrylic acid salt, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene or polyhexafluoropropylene.

[0041] The electrochemical device of the present application is not particularly limited, and may include any device that undergoes an electrochemical reaction. In some embodiments, 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, or a lithium ion polymer secondary battery, etc.

[0042] The preparation process of the electrochemical device is well known to those skilled in the art, and the present application has no particular limitation. For example, it may include but is not limited to the following steps: stacking the positive electrode sheet, the separator and the negative electrode sheet in order, and winding, folding and other operations as needed to obtain an electrode assembly of a wound structure, placing the electrode assembly in a packaging bag, injecting the electrolyte into the packaging bag and sealing it to obtain an electrochemical device; or stacking the positive electrode sheet, the separator and the negative electrode sheet in order, and then fixing the four corners of the entire stacked structure with tape to obtain an electrode assembly of a stacked structure, placing the electrode assembly in a packaging bag, injecting the electrolyte into the packaging bag and sealing it to obtain an electrochemical device. In addition, overcurrent protection elements, guide plates, etc. may also be placed in the packaging bag as needed to prevent pressure rise and overcharge and discharge inside the electrochemical device.

[0043] A third aspect of the present application provides an electronic device, comprising the electrochemical device in any embodiment of the present application.

[0044] The electronic device of the present application is not particularly limited, and it can be any electronic device known in the prior art. In some embodiments, the electronic device may include, but is not limited to, a laptop computer, a pen-input computer, a mobile computer, an electronic 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.

[0045] The present application provides a rubber tape, which comprises a substrate layer and a rubber layer arranged on one surface of the substrate layer, wherein the rubber layer comprises polyolefin and / or modified polyolefin, and the dissolution of the rubber tape in a lithium salt-free electrolyte is tested by cyclic voltammetry, and the number of reaction peaks is zero when the scanning voltage is 4.5V, and the oxidation peak intensity between the scanning voltage of 3V and 4.5V is less than 1×10 -7A has improved electrolyte resistance and adhesion, and reduced swelling. After being soaked in electrolyte, the adhesive tape provided by the present application can still effectively bind the pole ear, so that the welding area between the pole ear and the pole piece is not easy to be offset, and the welding area is not easy to be torn; after being soaked in electrolyte for a long time at high temperature, the thickness of the adhesive tape changes little, which can ensure that there is no bulge on the appearance of the electrochemical device after high-temperature storage, thereby helping to improve the safety performance of the electrochemical device and extend the service life of the electrochemical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the present application and the prior art, the following briefly introduces the drawings required for use in the embodiments and the prior art. Obviously, the drawings described below are only some embodiments of the present application.

[0047] Figure 1 The Fourier transform infrared absorption spectrum curves of the adhesive tapes of Example 1 and Comparative Example 1;

[0048] Figure 2 A schematic diagram of a positive electrode sheet in some embodiments of the present application;

[0049] Figure 3 It is a schematic cross-sectional view of an electrochemical device in some embodiments of the present application.

[0050] Figure numerals: 10, positive electrode plate, 11, positive electrode tab, 12, adhesive tape, 20, negative electrode plate, 30, separator. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other technical solutions obtained by ordinary technicians in the field belong to the scope of protection of the present application.

[0052] Figure 1 The Fourier transform infrared absorption spectrum curve graph of the adhesive tape of Example 1 and Comparative Example 1 is shown. It can be seen from the graph that the absorption peaks corresponding to the carbonyl group and ester group on the surface of the adhesive tape in Example 1 basically disappear, while the carbonyl group and ester group still exist on the surface of the adhesive tape in Comparative Example 1, which indicates that the adhesive tape provided in the present application has low swelling characteristics.

[0053] Figure 2 The positive electrode sheet in some embodiments of the present application is shown. The positive electrode sheet 10 includes a positive electrode tab 11 connected to the positive electrode sheet 10 , and adhesive tape 12 is provided at the connection between the positive electrode tab 11 and the positive electrode sheet 10 .

[0054] Specifically, the adhesive tape can be set at the connection between the positive electrode tab and the positive electrode sheet; the adhesive tape can also be set at the connection between the negative electrode tab and the negative electrode sheet; the adhesive tape can also be set at the connection between the positive electrode tab and the positive electrode sheet and at the connection between the negative electrode tab and the negative electrode sheet at the same time. The specific setting position of the adhesive tape can be selected according to actual conditions.

[0055] Figure 3 The cross section of the electrochemical device in some embodiments of the present application is shown. The electrochemical device is a wound structure, including a positive electrode sheet 10, a negative electrode sheet 20 and a separator 30. A tape 12 is provided at the end area of ​​the negative electrode sheet 20.

[0056] Specifically, the adhesive tape can be set at the end area of ​​the positive electrode sheet and / or the end area of ​​the negative electrode sheet. The adhesive tape can also be set at the end area of ​​the positive electrode sheet and / or the end area of ​​the negative electrode sheet, and also set at the connection between the positive electrode ear and the positive electrode sheet and / or the connection between the negative electrode ear and the negative electrode sheet. The specific setting position of the adhesive tape can be selected according to actual conditions.

[0057] It should be noted that in the specific embodiments of the present application, 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 a lithium-ion battery.

[0058] Example

[0059] The following examples and comparative examples are given to more specifically describe the embodiments of the present application. Various tests and evaluations were performed according to the following methods. In addition, unless otherwise specified, "parts" and "%" are based on mass.

[0060] Test methods and equipment:

[0061] Adhesion test:

[0062] The adhesive tape was pasted on the Al foil and cut into strip samples of 20mm×60mm. The samples were hot-pressed at a temperature of 85℃ and a pressure of 1MPa for 40min. Then the samples were pasted on the steel plate with double-sided tape (Nitto 5000NS) (the adhesion length was not less than 40mm), and the steel plate was fixed in the corresponding position of the high-speed rail tensile testing machine. The other end of the sample that was not adhered to the steel plate was pulled up, and the sample was clamped in the chuck, where the pulled-up sample part had an angle of 180° with the steel plate in space. The chuck was pulled at a speed of 50mm / min, and the average tensile force in the stable area was finally measured and recorded as the bonding force after hot pressing.

[0063] The adhesive tape was pasted on the Al foil and cut into strip samples of 20mm×60mm. The samples were hot-pressed at a temperature of 85℃ and a pressure of 1MPa for 40min. Then, the samples were immersed in an electrolyte at 85℃ for 4h. The samples were pasted on a steel plate with double-sided tape (the adhesion length was not less than 40mm), and the steel plate was fixed in the corresponding position of the high-speed rail tensile testing machine. The other end of the sample that was not adhered to the steel plate was pulled up, and the sample was clamped in the chuck, where the pulled-up sample part had an angle of 180° with the steel plate in space. The chuck was pulled at a speed of 50mm / min, and the average tensile force in the stable area was finally measured and recorded as the bonding force after immersion in the electrolyte.

[0064] The organic solvent of the electrolyte is ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and ethyl propionate (EP), and the mass ratio of EC: PC: DEC: EP is 3:1:3:3, and the solute is lithium hexafluorophosphate (LiPF 6 ), LiPF 6 The concentration is 1 mol / L.

[0065] Glue overflow test:

[0066] The initial width of the adhesive tape was measured, and then the maximum width of the adhesive tape was measured after the adhesive tape was subjected to heat pressing at a temperature of 85° C. and a pressure of 1 MPa to 2 MPa for 1 hour, which was the overflow width. Ten samples of the adhesive tape in each embodiment and comparative example were tested, and the maximum overflow width of the adhesive tape was the average value of the difference between the overflow width of the ten samples and the initial width.

[0067] Swelling thickness test:

[0068] Cut the adhesive tape into strips of 20mm×60mm, measure the initial thickness of the adhesive tape, and then stick the adhesive tape on the Al foil and soak it in the electrolyte for 24h at a temperature of 85°C. After soaking, take it out and dry it. Use a micrometer to measure the thickness of the edge of the adhesive tape within 5min. Randomly select 10 places for measurement, and the average value is the swelling thickness of the adhesive tape. 10 samples of the adhesive tape in each embodiment and comparative example are tested, and the swelling thickness of the adhesive tape is the average value of the difference between the swelling thickness of the 10 samples and the initial thickness. The electrolyte is the same as the electrolyte in the above-mentioned adhesion test.

[0069] Turbidity test:

[0070] Select a fixed position in a room, determine the light source and angle, use A4 paper as the background, place the glass sample bottle containing the electrolyte on the A4 paper, compare the color on the Pantone international standard colorimetric card, record the color number closest to the color, and record it as the initial color number after confirmation by 3 people. Paste the adhesive tape on the Al foil, cut it into 20mm×60mm strip samples, heat press for 40min at 85℃ and 1MPa, cool it to room temperature and put it into the sample bottle, soak it in 85℃ electrolyte for 12h, and take out the sample. Using the same method as above, record the color number of the electrolyte as the color number after soaking. Compare whether the initial color number and the color number after soaking are consistent. If they are consistent, it means that the turbidity of the electrolyte has not changed much; if they are inconsistent, it means that the turbidity of the electrolyte has changed greatly. Among them, the electrolyte is the same as the electrolyte in the above-mentioned adhesion test.

[0071] Drop test:

[0072] The battery prepared in each embodiment or comparative example is charged to a full charge voltage at a constant current of 0.5C rate at room temperature, and is charged to a current of 0.05C at a constant voltage to make it in a fully charged state, and then the voltage of the lithium-ion battery is adjusted to 68% SOC; the voltage and internal resistance are measured so that the voltage of the lithium-ion battery is 3.94V to 3.99V; a constant pressure tester and a special metal or plastic mold for falling are used to put the lithium-ion battery into the constant pressure tester, and air is compressed immediately after it is close to the lithium-ion battery (within 1 minute), and the lithium-ion battery is pressed for 7 seconds using a 5kg pressing block; then it is allowed to stand for 1 hour, and the voltage and internal resistance are measured again; the appearance of the battery is checked for damage, leakage, expansion, corrosion, etc. After completion, the cover of the special metal or plastic mold for falling is covered, and the screws are tightened to complete the preparation for the drop test.

[0073] In the following order, the battery is freely dropped from 6 directions at a height of 1.8 meters: head->tail->right corner of the head->right corner of the tail->left corner of the head->left corner of the tail, the angle between the battery and the ground is: 45°±15°, and repeated 7 rounds. After each round of testing, if leakage, heating, smoking, fire or voltage reduction of more than 50mV is found, the drop is stopped. After the drop is completed, the battery is left at room temperature for 24 hours and then the voltage and internal resistance are measured. The standard for passing the drop is no fire and no leakage. 10 batteries prepared in each embodiment or comparative example are tested, and the number of passed batteries is recorded.

[0074] Tab welding tensile test:

[0075] A high-speed rail tensile testing machine is used to tear apart the positive electrode ear and the positive electrode sheet (negative electrode ear and negative electrode sheet) at an angle of 180° and 60 mm / min, so that the welding areas are separated from each other. The stable tensile force recorded during separation is the welding tensile force.

[0076] High temperature storage thickness expansion test:

[0077] Place the battery in a 25°C constant temperature box and let it stand for 30 minutes to allow the battery to reach a constant temperature. Charge at a constant current of 1C to 4.45V, charge at a constant voltage to a current of 0.05C, and then discharge at a constant current of 1C to 2.8V, and record the discharge capacity as the initial capacity of the battery. Then charge at a constant current of 0.5C to 4.45V, charge at a constant voltage to a current of 0.05C, and use a micrometer to test and record the thickness of the battery as the initial thickness. Transfer the test battery to a constant temperature box with a storage temperature of 85°C for storage for 24 hours. After the storage is completed, the thickness of the test battery is the hot test storage thickness. Transfer the battery to a 25°C constant temperature box and let it stand for 60 minutes. The thickness of the test battery is the cold test storage thickness.

[0078] Thermal measurement: 85°C storage for 24 hours: thickness expansion ratio = (thermal storage thickness - initial thickness) / initial thickness × 100%.

[0079] Test of dissolution of adhesive tape in electrolyte:

[0080] The adhesive tape was pasted on the Al foil and cut into strip samples of 20 mm × 60 mm. After soaking in a lithium-free electrolyte at 85°C for 24 hours, the adhesive tape was taken out and the cyclic voltammetry (CV) curve of the lithium-free electrolyte was tested using a platinum electrode.

[0081] The lithium salt-free electrolyte is obtained by mixing ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and ethyl propionate (EP) in a mass ratio of 3:1:3:3.

[0082] Fourier transform infrared absorption spectroscopy test:

[0083] Fourier transform infrared absorption spectrometer (manufacturer: Thermo Fisher Scientific, USA, model: Nicolet iS50) was used to test the contents of carboxyl and ester groups on the surface of adhesive tape using total reflection method and KRS-5 prism.

[0084] Example 1-1

[0085] <Preparation of positive electrode sheet>

[0086] The positive electrode active material lithium nickel manganese cobalt ternary material (NCM613), the conductive agent conductive carbon black (Super P), and the binder polyvinylidene fluoride are mixed in a mass ratio of 97:1.4:1.6, and N-methylpyrrolidone (NMP) is added. The system is stirred under the action of a vacuum mixer until it becomes uniform and transparent to obtain a positive electrode slurry, wherein the solid content of the positive electrode slurry is 75%. The positive electrode slurry is evenly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 9μm, and the aluminum foil is dried at 85°C to obtain a positive electrode sheet with a coating thickness of 110μm and a single-sided positive electrode material layer. Repeat the above steps on the other surface of the aluminum foil to obtain a positive electrode sheet coated with a positive electrode active material on both sides. Then, after cold pressing, cutting, and slitting, it is dried under vacuum conditions at 85°C for 4h to obtain a positive electrode sheet with a specification of (74mm×867mm). The Dv50 of the positive electrode active material is 1 μm, and the positive electrode sheet includes a positive electrode ear.

[0087] <Preparation of negative electrode sheet>

[0088] The negative electrode active material artificial graphite, the conductive agent Super P, the thickener sodium carboxymethyl cellulose (CMC-Na), and the binder styrene-butadiene rubber (SBR) are mixed in a mass ratio of 96.4:1.5:0.5:1.6, and deionized water is added to obtain a negative electrode slurry under the action of a vacuum mixer, wherein the solid content of the negative electrode slurry is 70%. The negative electrode slurry is evenly coated on one surface of a negative electrode current collector copper foil with a thickness of 8 μm, and the copper foil is dried at 85°C to obtain a negative electrode sheet with a coating thickness of 130 μm and a single-sided negative electrode material layer. Repeat the above steps on the other surface of the aluminum foil to obtain a negative electrode sheet coated with negative electrode active materials on both sides. Then, after cold pressing, cutting, and slitting, it is dried under vacuum conditions at 120°C for 12 hours to obtain a negative electrode sheet with a specification of (74mm×867mm). Among them, the negative electrode sheet includes a negative electrode ear.

[0089] <Preparation of Electrolyte>

[0090] In a dry argon atmosphere glove box, organic solvents ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and ethyl propionate (EP) were mixed at a mass ratio of EC: PC: DEC: EP = 3:1:3:3, and then lithium salt LiPF was added to the organic solvent. 6 Dissolve and mix evenly. Among them, LiPF 6 The concentration in the electrolyte is 1 mol / L. According to the Pantone international standard colorimetric card, the initial color number E of the electrolyte is 1225C.

[0091] <Preparation of Separator Film>

[0092] Aqueous polyvinylidene fluoride (PVDF), ceramics, and polypropylene were mixed in a mass ratio of 1:8:1, added to deionized water, and stirred to obtain a coating slurry with a solid content of 50%. The coating slurry was evenly coated on one surface of a polyethylene (PE) film (provided by Celgard) with a thickness of 7 μm, and dried at 85°C to obtain a single-sided coated isolation film with a coating thickness of 5 μm. The above steps were repeated on the other surface of the isolation film to obtain a double-sided coated isolation film. Then, after drying and cold pressing, the isolation film was obtained.

[0093] <Preparation of adhesive tape>

[0094] The adhesive tape comprises an adhesive layer arranged on one surface of the base material layer, wherein the thickness of the adhesive tape is 25 μm, the thickness of the adhesive layer is 12 μm, and the thickness of the base material layer is 12 μm.

[0095] Polyethylene, thermoplastic elastomer styrene-ethylene-butylene-styrene block copolymer, petroleum resin C5, filler titanium dioxide, antioxidant diphenylamine are mixed evenly in a mass ratio of 60:25:5:5:5, then coated on the substrate layer to form an adhesive layer, and dried at 120°C to obtain adhesive tape. The molecular weight of polyethylene is 225,000.

[0096] The substrate layer is a polyethylene terephthalate (PET) film.

[0097] <Preparation of lithium-ion batteries>

[0098] 20mm×45mm adhesive tape is respectively pasted to the connection between the positive electrode ear and the positive electrode sheet, and the connection between the negative electrode ear and the negative electrode sheet, and then the positive electrode sheet, the separator, and the negative electrode sheet are stacked in order, so that the separator is between the positive electrode sheet and the negative electrode sheet to play an isolating role, and the electrode assembly is wound. The electrode assembly is placed in an aluminum-plastic film packaging bag, and the electrolyte is injected after drying. After vacuum packaging, standing, formation, degassing, trimming and other processes, a lithium-ion battery is obtained. Among them, the formation conditions are to charge to 3.3V at a constant current of 0.02C, then charge to 3.6V at a constant current of 0.1C, and finally charge to 4.45V at a constant current of 0.2C.

[0099] In Examples 1-2 to 1-7, except for adjusting the type and mass percentage of component 1 of the adhesive layer according to Table 1, the rest are the same as Example 1-1.

[0100] In Examples 2-1 to 2-6, except that the weight average molecular weight of component 1 of the adhesive layer is adjusted according to Table 2, the rest is the same as that of Example 1-2.

[0101] In Examples 3-1 to 3-16, except for adjusting the mass percentage of component 1 of the adhesive layer, the composition of component 2 of the adhesive layer, and the mass percentage of each component of component 2 of the adhesive layer according to Table 3, the rest is the same as Example 1-2.

[0102] In Examples 4-1 to 4-12, except for adjusting the thickness of the adhesive layer, the thickness of the substrate layer, and the material of the substrate layer according to Table 4, the rest is the same as that of Example 1-2.

[0103] In Comparative Example 1, except that polyethylene is replaced by polyacrylate, the rest is the same as Example 1.

[0104] The relevant preparation parameters and performance tests of each embodiment and comparative example are shown in Tables 1 to 4.

[0105]

[0106]

[0107]

[0108]

[0109] With reference to Table 1, it can be seen from Examples 1-1 to 1-7 and Comparative Example 1-1 that when the adhesive layer includes polyolefin and / or modified polyolefin, the adhesive force and electrolyte resistance of the adhesive tape are improved, the maximum overflow width and swelling thickness change of the adhesive tape are reduced, and the safety performance and storage performance of the electrochemical device are also improved.

[0110] Referring to Table 2, it can be seen from Examples 1-2 and 2-1 to 2-6 that when the weight average molecular weight of the polyolefin and the modified polyolefin is within the range of the present application, the adhesive force of the adhesive tape and the safety performance of the electrochemical device are higher. The obtained adhesive tape has both good adhesive force and electrolyte resistance, the maximum overflow width and swelling thickness of the adhesive tape are small, and the electrochemical device has good safety performance and storage performance.

[0111] The mass percentage of the components in the adhesive layer usually affects the performance of the adhesive tape. Referring to Table 3, it can be seen from Examples 1-2 and 3-1 to 3-16 that when the mass percentage of the polyolefin and / or modified polyolefin is within the range of the present application, the electrolyte resistance of the adhesive tape and the safety performance of the electrochemical device are higher. The obtained adhesive tape has good adhesion and electrolyte resistance, the maximum overflow width and swelling thickness of the adhesive tape change little, and the electrochemical device has good safety performance and storage performance.

[0112] The thickness of the adhesive layer, the thickness of the substrate layer, and the type of material of the substrate layer usually affect the performance of the adhesive tape, and then affect the performance of the electrochemical device. Referring to Table 4, it can be seen from Examples 1-2, 4-1 to 4-5 that the thickness of the adhesive layer is within the scope of the present application, and the obtained adhesive tape has a smaller overflow width; it can be seen from Examples 1-2, 4-6 to 4-12 that the thickness of the substrate layer and the type of material of the substrate layer are within the scope of the present application, and the obtained adhesive tape has good adhesion and electrolyte resistance, the maximum overflow width and swelling thickness of the adhesive tape change little, and the electrochemical device has good safety performance and storage performance. It can be seen from Examples 1-2, 4-1 to 4-12 that when the thickness of the adhesive tape, the thickness of the substrate layer, and the substrate layer are within the scope of the present application, the obtained adhesive tape has both good adhesion and electrolyte resistance, the maximum overflow width and swelling thickness of the adhesive tape change little, and the electrochemical device has both good safety performance and storage performance.

[0113] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A gummed paper comprising a substrate layer and an adhesive layer disposed on one surface of the substrate layer, wherein the adhesive layer comprises polyolefin and / or modified polyolefin, in, The dissolution of the adhesive tape in the lithium salt-free electrolyte was tested by cyclic voltammetry. The number of reaction peaks was zero when the scanning voltage was 4.5 V, and the oxidation peak intensity was less than 1×10 -7 A; The maximum overflow width of the adhesive tape is 0 mm to 1 mm.

2. The adhesive tape according to claim 1, in, The polyolefin includes polyethylene and / or polypropylene, and the modified polyolefin includes maleic anhydride-modified polyethylene and / or maleic anhydride-modified polypropylene.

3. The adhesive tape according to claim 1, in, The adhesive layer further comprises a thermoplastic elastomer, wherein the thermoplastic elastomer comprises at least one of styrene-ethylene-butylene-styrene block copolymer, polyurethane, polyolefin or polyamide, wherein the polyolefin comprises polyisobutylene and / or polybutadiene; Based on the mass of the adhesive layer, the mass percentage of the polyolefin and / or modified polyolefin is 45% to 85%, and the mass percentage of the thermoplastic elastomer is 10% to 35%.

4. The adhesive tape according to claim 1, in, The weight average molecular weight of the polyolefin and / or modified polyolefin is 50,000 to 400,000.

5. The adhesive tape according to claim 1, in, Based on the total mass of the adhesive layer, the mass percentage of the polyolefin and / or modified polyolefin is 45% to 85%.

6. The adhesive tape according to claim 1, in, The thickness of the adhesive layer is 4 μm to 20 μm.

7. The adhesive tape according to claim 1, in, The adhesive force of the adhesive layer after hot pressing is 0.2 N / mm to 1.0 N / mm.

8. The adhesive tape according to claim 1, in, The lithium salt-free electrolyte includes a mixed solvent of ethylene carbonate, propylene carbonate, diethyl carbonate and ethyl propionate in a mass ratio of 3:1:3:

3.

9. The adhesive tape according to claim 1, in, The adhesive layer has an adhesive force of 0.1 N / mm to 1.0 N / mm after being immersed in an electrolyte at 85° C. for 4 hours.

10. The adhesive tape according to claim 1, in, The thickness A of the adhesive tape after being immersed in an electrolyte at 85° C. for 24 hours and the thickness B of the adhesive tape before being immersed in the electrolyte satisfy the following: 0 μm<AB≤2 μm.

11. The adhesive tape according to claim 1, in, After the adhesive tape is immersed in an electrolyte at 85° C. for 12 hours, the turbidity D of the electrolyte and the turbidity E of the electrolyte before immersion satisfy 100° C. < DE ≤ 1535° C.

12. The adhesive tape according to claim 1, in, The substrate layer includes at least one of polyethylene terephthalate, polyimide or polypropylene, and the thickness of the substrate layer is 4 μm to 40 μm.

13. The adhesive tape according to claim 1, in, The adhesive tape further includes a release paper, and the release paper is arranged on a surface of the adhesive layer facing away from the substrate layer.

14. An electrochemical device comprising the adhesive tape according to any one of claims 1 to 13.

15. The electrochemical device according to claim 14 further comprises a pole piece, wherein the pole piece comprises a pole ear, and the bonding force between the adhesive layer in the adhesive paper and the pole ear or between the adhesive layer in the adhesive paper and the pole piece is 0.2 N / mm to 1.0 N / mm.

16. An electronic device comprising the electrochemical device according to any one of claims 14 to 15.

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