Electrochemical device and electronic device

Abstract

The invention provides an electrochemical device and an electronic device, the electrochemical device comprises a positive pole piece, a negative pole piece and a diaphragm, a functional layer is arranged between the positive pole piece and the diaphragm, the functional layer comprises porous aerogel and a phase change heat absorption material, and the heat conductivity coefficient of the porous aerogel is 0.01 W / (m.k)-0.05 W / (m.k). The porous aerogel comprises at least one of silica aerogel, metal oxide aerogel, polymer aerogel and carbon aerogel; the phase change heat absorption material comprises at least one of gallium alloy, indium tin alloy, paraffin, salt hydrate or fatty acid; the thickness of the functional layer is 1-5 [mu] m. Based on the total mass of the functional layer, the total mass percentage of the phase change heat absorption material and the porous aerogel is 80%-98%. The characteristics are met by regulating and controlling the types of the functional layer and the content of each component, and the design of the functional layer can reduce the temperature rise rate of the positive pole piece while improving the heat dissipation performance of the functional layer, so that the thermal stability safety performance and the crushing-resistant safety performance of the electrochemical device are improved.

Description

Technical Field

[0001] The present application relates to the field of electrochemistry technology, and particularly to an electrochemical device and an electronic device. Background Art

[0002] In modern battery technology, thermal management has always been a key challenge, especially for high-energy-density lithium-ion batteries. During the operation of lithium-ion batteries, chemical reactions between the positive electrode and the electrolyte generate a large amount of heat. If these heats are not managed and controlled in a timely and effective manner, they may quickly conduct to the negative electrode, triggering thermal runaway and ultimately leading to the failure of lithium-ion batteries or even serious safety accidents.

[0003] The prior art encapsulates a flame retardant in an amorphous zirconia nanotube material through a phase change heat absorption material to form a composite amorphous zirconia nanotube material. Coating it on the separator can enable lithium-ion batteries to automatically release the flame retardant at the thermal runaway temperature to improve the safety of lithium-ion batteries. However, the flame retardant can only reduce the combustion degree when the lithium-ion battery burns, and cannot prevent the combustion of the lithium-ion battery or reduce the heat accumulation before the lithium-ion battery burns, nor can it block the heat conduction from the main heat-generating body, the positive electrode side, to the negative electrode. Therefore, there is an urgent need in the market for a lithium-ion battery with good thermal stability and safety performance. Summary of the Invention

[0004] The purpose of the present application is to provide an electrochemical device and an electronic device to improve the thermal stability and safety performance and the pressure resistance safety performance of the electrochemical device. The specific technical solutions are as follows:

[0005] It should be noted that in the present application, a lithium-ion battery is used as an example of the electrochemical device to explain the present application, but the electrochemical device of the present application is not limited to lithium-ion batteries. The specific technical solutions are as follows:

[0006] The first aspect of the present application provides an electrochemical device, which includes a positive electrode sheet, a negative electrode sheet and a separator. A functional layer is provided between the positive electrode sheet and the separator. The functional layer includes a porous aerogel and a phase change heat absorption material. The thermal conductivity of the porous aerogel is 0.01 W / (m·k) to 0.05 W / (m·k). The porous aerogel includes at least one of silica aerogel, metal oxide aerogel, polymer aerogel and carbon aerogel; the phase change heat absorption material includes at least one of gallium alloy, indium tin alloy, paraffin, hydrate or fatty acid; the thickness of the functional layer is 1 μm to 5 μm; based on the total mass of the functional layer, the total mass percentage content of the phase change heat absorption material and the porous aerogel is 80% to 98%. By providing a functional layer containing a porous aerogel and a phase change heat absorption material between the positive electrode sheet and the separator, and regulating the type and thickness of the functional layer and the mass percentage content of each component to meet the above characteristics, while improving the heat dissipation performance of the functional layer, the rate of increase in the temperature of the positive electrode sheet can be reduced, and the rapid diffusion of heat generated by the positive electrode sheet can be slowed down, thereby improving the thermal stability and safety performance and the pressure resistance and collapse safety performance of the electrochemical device.

[0007] In an embodiment of the present application, based on the total mass of the functional layer, the mass percentage content of the phase change heat absorption material is 8% to 57%; the mass percentage content of the porous aerogel is 23% to 72%. By regulating the mass percentage content of the phase change heat absorption material and the porous aerogel within the above range, the phase change heat absorption material and the porous aerogel can have appropriate masses to produce a better synergistic effect, so that the functional layer can better block the heat generated by the positive electrode sheet and improve the thermal stability and safety performance of the electrochemical device.

[0008] In an embodiment of the present application, the metal oxide aerogel is selected from at least one of titanium oxide aerogel, aluminum oxide aerogel, zirconium oxide aerogel or magnesium oxide aerogel; the polymer aerogel is selected from at least one of aramid aerogel, polyurethane aerogel, polystyrene aerogel, polyimide aerogel, polyethylene aerogel, polyvinyl alcohol aerogel or polyacrylate aerogel. By selecting the above porous aerogel materials, the porous aerogel can have appropriate thermal conductivity and porosity, and can better reduce the rate of increase in the temperature of the positive electrode sheet, thereby improving the thermal stability and safety performance of the electrochemical device.

[0009] In an embodiment of the present application, the particle size D v 50 of the porous aerogel is 0.1 μm to 2 μm. By regulating the particle size D v 50 of the porous aerogel within the above range, the density and uniformity of the functional layer can be improved, and the heat dissipation performance of the functional layer can be better improved, thereby improving the thermal stability and safety performance of the electrochemical device.

[0010] In an embodiment of the present application, the density of the porous aerogel is 1 kg / m3 to 500 kg / m 3 。By adjusting the density of the porous aerogel within the above range, the porous aerogel has a low density. While enabling the electrochemical device to have both a high energy density and a lightweight characteristic layer, it can ensure that the performance of the functional layer in terms of thermal management is not lost, and improve the thermal stability and safety performance of the electrochemical device.

[0011] In an embodiment of the present application, the coating porosity of the functional layer is 70% to 95%. By implanting a phase change heat absorption material or other functional materials in the porous aerogel, the porosity of the functional layer is within the above range, which can better extend the heat conduction path, enable the functional layer to better block the heat generated by the positive electrode sheet, and improve the thermal stability and safety performance of the electrochemical device.

[0012] In an embodiment of the present application, the hydrate includes at least one of sodium sulfate decahydrate, magnesium sulfate heptahydrate, calcium chloride hexahydrate, or zinc chloride hexahydrate; the fatty acid includes at least one of lauric acid, stearic acid, palmitic acid, myristic acid, or oleic acid. By selecting the above-mentioned hydrate compounds and fatty acids as the phase change heat absorption materials, the phase change heat absorption materials have a good phase change heat absorption effect, thereby improving the thermal stability and safety performance of the electrochemical device.

[0013] In an embodiment of the present application, the functional layer further includes inorganic nanoparticles, and the inorganic nanoparticles include at least one of titanium dioxide (TiO2), aluminum oxide (Al2O3), or ceramic particles. The ceramic particles may include at least one of aluminum oxide ceramic particles, zirconia ceramic particles, or silicon carbide ceramic particles. The particle size of the inorganic nanoparticles is D 1v 50, 5 nm < D 1v 50 < 200 nm. Based on the total mass of the functional layer, the mass percentage content of the inorganic nanoparticles is 0% to 10%. When the particle size and mass percentage content of the inorganic nanoparticles meet the above characteristics, the functional layer can simultaneously have good heat dissipation performance and mechanical support ability, and improve the pressure resistance and safety performance of the electrochemical device.

[0014] In an embodiment of the present application, the functional layer further includes a porous adsorption material, and the porous adsorption material includes at least one of zeolite or activated carbon; based on the total mass of the functional layer, the mass percentage content of the porous adsorption material is 0% to 10%. When the mass percentage content of the porous adsorption material meets the above range, it can absorb excess gas while reducing the influence of the porous adsorption material on the porosity and heat dissipation performance of the functional layer. Therefore, by setting a porous adsorption material in the functional layer, the thermal stability and safety performance of the electrochemical device can be improved.

[0015] In an embodiment of the present application, the functional layer further includes a functional conductive agent and a solid electrolyte. The functional conductive agent includes at least one of acetylene black or Ketjen black, and the solid electrolyte includes at least one of a polymer solid electrolyte or a ceramic solid electrolyte. Based on the total mass of the functional layer, the mass percentage content of the functional conductive agent is 0% to 2%, and the mass percentage content of the solid electrolyte is 0% to 2%. By controlling the types and mass percentage contents of the functional conductive agent and the solid electrolyte in the functional layer to meet the above ranges, the electrical conductivity and ion transport performance of the electrochemical device can be improved while enhancing the thermal stability and safety performance of the electrochemical device.

[0016] In an embodiment of the present application, the polymer solid electrolyte includes at least one of polyethylene oxide, polyacrylonitrile-based electrolyte, polymethyl methacrylate-based electrolyte, polystyrene-polyethylene oxide block copolymer, or polyurethane-based electrolyte; the ceramic solid electrolyte includes at least one of yttrium-doped zirconia, lithium sulfide-based compound, lithium phosphate-based compound, lithium titanate, or Li7La3Zr2O 12 In the above range. By controlling the type of the solid electrolyte, the functional layer can better improve the ion transport performance of the electrochemical device without affecting the heat dissipation ability of the functional layer, thereby enhancing the thermal stability and safety performance of the electrochemical device.

[0017] In an embodiment of the present application, the functional layer is disposed on the surface of the positive electrode plate adjacent to the separator or on the surface of the separator adjacent to the positive electrode plate. By controlling the setting position of the functional layer to meet the above characteristics, the thermal stability and safety performance of the electrochemical device can be improved.

[0018] The second aspect of the present application provides an electronic device, which includes the electrochemical device in any of the foregoing embodiments. Therefore, the electronic device has good thermal stability and safety performance and crush resistance safety performance.

[0019] Advantages of the present application:

[0020] The present application provides an electrochemical device and an electronic device. The electrochemical device includes a positive electrode sheet, a negative electrode sheet, and a separator. A functional layer is disposed between the positive electrode sheet and the separator. The functional layer includes a porous aerogel and a phase change heat absorption material. The thermal conductivity of the porous aerogel is from 0.01 W / (m·K) to 0.05 W / (m·K). The porous aerogel includes at least one of silica aerogel, metal oxide aerogel, polymer aerogel, and carbon aerogel; the phase change heat absorption material includes at least one of gallium alloy, indium tin alloy, paraffin, hydrated salt, or fatty acid; the thickness of the functional layer is from 1 μm to 5 μm; based on the total mass of the functional layer, the total mass percentage content of the phase change heat absorption material and the porous aerogel is from 80% to 98%. By regulating the type of the functional layer and the content of each component to meet the above characteristics, when the electrochemical device reaches the thermal runaway temperature, the functional layer design can improve the heat dissipation performance of the functional layer while reducing the rate of increase in the temperature of the positive electrode sheet, thereby improving the thermal stability and safety performance and the pressure resistance and collapse safety performance of the electrochemical device.

[0021] Of course, it is not necessary for any product or method implementing the present application to simultaneously achieve all the above-mentioned advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and those of ordinary skill in the art can also obtain other embodiments according to these drawings.

[0023] Figure 1 Schematic structural diagram of an electrochemical device according to an embodiment of the present application;

[0024] In the figure, 11 is the positive electrode sheet, 12 is the functional layer, 13 is the separator, and 14 is the negative electrode sheet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following will clearly and completely describe the technical solutions in the present application in conjunction with the embodiments of the present application and the drawings. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the present application belong to the scope of protection of the present application.

[0026] It should be noted that in the present application, a lithium-ion battery is used as an example of the electrochemical device to explain the present application, but the electrochemical device of the present application is not limited to lithium-ion batteries. The specific technical solutions are as follows:

[0027] The first aspect of the present application provides an electrochemical device, which includes a positive electrode plate, a negative electrode plate, and a separator. A functional layer is provided between the positive electrode plate and the separator. The functional layer includes a porous aerogel and a phase change heat absorption material. The thermal conductivity of the porous aerogel is from 0.01 W / (m·K) to 0.05 W / (m·K). Exemplarily, the thermal conductivity of the porous aerogel can be 0.01 W / (m·K), 0.02 W / (m·K), 0.03 W / (m·K), 0.04 W / (m·K), 0.05 W / (m·K), or a range composed of any two of the above values. The porous aerogel includes at least one of silica aerogel, metal oxide aerogel, polymer aerogel, and carbon aerogel; the phase change heat absorption material includes at least one of gallium alloy, indium tin alloy, paraffin, hydrate, or fatty acid; the thickness of the functional layer is from 1 μm to 5 μm. Exemplarily, the thickness of the functional layer can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, or a range composed of any two of the above values. Based on the total mass of the functional layer, the sum of the mass percentage contents of the phase change heat absorption material and the porous aerogel is from 80% to 98%. Exemplarily, the sum of the mass percentage contents of the phase change heat absorption material and the porous aerogel can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or a range composed of any two of the above values.

[0028] The inventors' research found that during the operation of the electrochemical device, a large amount of heat is generated by the chemical reaction between the positive electrode plate and the electrolyte. If these heats are not managed and controlled in a timely and effective manner, they will quickly conduct to the negative electrode, triggering thermal runaway and affecting the normal operation of the electrochemical device or even posing safety hazards. The electrochemical device provided by the present application includes a functional layer provided between the positive electrode plate and the separator. The functional layer includes a porous aerogel and a phase change heat absorption material. Due to its unique grid structure, the porous aerogel has large grid pores inside, with low density and large porosity, and can serve as a framework for implanting functional materials in the functional layer. Compared with other materials of the same mass, the low density and large porosity of the porous aerogel can better extend the heat conduction path, making the porous aerogel have a low thermal conductivity, thereby reducing the rate of increase in the temperature of the positive electrode plate. The phase change heat absorption material is also implanted in the pores of the porous aerogel. When the operating temperature of the positive electrode plate reaches or exceeds the phase change temperature, the phase change heat absorption material can absorb heat and undergo a phase change, further reducing the rate of increase in the temperature of the positive electrode plate. At the same time, the low thermal conductivity of the porous aerogel can better reduce the possibility that the heat absorbed by the phase change heat absorption material during the phase change process quickly diffuses into the functional layer. The two work together to effectively block the heat generated by the positive electrode plate, make the internal temperature of the electrochemical device uniform, reduce the possibility of local overheating, and reduce the thermal runaway risk of the electrochemical device.

[0029] In this application, the thickness of the functional layer is between 1 μm and 5 μm, enabling the functional layer to better block the heat generated by the positive electrode plate while also reducing the impact on the energy density of the electrochemical device. When the thickness of the functional layer is too small, for example, less than 1 μm, the functional layer has a small effect on blocking heat generation; when the thickness of the functional layer is too large, for example, greater than 5 μm, the functional layer is too thick, which will affect the ion transport performance and energy density of the electrochemical device.

[0030] Therefore, in this application, by setting a functional layer containing porous aerogel and phase change heat absorption material between the positive electrode plate and the separator, regulating the type and thickness of the functional layer and the mass percentage content of each component to meet the above characteristics, while improving the heat dissipation performance of the functional layer, the rate of increase in the temperature of the positive electrode plate can be reduced, and the rapid diffusion of the heat generated by the positive electrode plate can be slowed down, thereby improving the thermal stability and safety performance and the pressure resistance and collapse safety performance of the electrochemical device.

[0031] Figure 1 It is a schematic structural diagram of an electrochemical device according to an embodiment of this application. In the figure, 11 is the positive electrode plate, 12 is the functional layer, 13 is the separator, and 14 is the negative electrode plate. As shown in the figure, setting the functional layer between the positive electrode plate and the separator can reduce the rate of increase in the temperature of the positive electrode plate and slow down the rapid diffusion of the heat generated by the positive electrode plate, thereby improving the thermal stability and safety performance of the electrochemical device.

[0032] In an embodiment of this application, based on the total mass of the functional layer, the mass percentage content of the phase change heat absorption material is 8% to 57%. Exemplarily, the mass percentage content of the phase change heat absorption material can be 8%, 12%, 16%, 20%, 24%, 28%, 32%, 36%, 40%, 44%, 48%, 52%, 57% or a range composed of any two of the above values; the mass percentage content of the porous aerogel is 23% to 72%. Exemplarily, the mass percentage content of the porous aerogel can be 23%, 27%, 31%, 35%, 39%, 43%, 47%, 51%, 55%, 59%, 63%, 67%, 72% or a range composed of any two of the above values. By regulating the mass percentage content of the phase change heat absorption material and the porous aerogel within the above range, the phase change heat absorption material and the porous aerogel can have appropriate masses to produce a good synergistic effect, enabling the functional layer to better block the heat generated by the positive electrode plate and enhancing the thermal stability and safety performance of the electrochemical device.

[0033] In an embodiment of this application, the metal oxide aerogel is selected from at least one of titanium oxide aerogel (TiO2), aluminum oxide aerogel (Al2O3), zirconium oxide aerogel (ZrO2), or magnesium oxide aerogel (MgO); the polymer aerogel is selected from aramid aerogel ((C 14 H10 N2O2) n , with a molecular weight of 200,000 Da to 500,000 Da), polyurethane aerogel ((C 10 H8N2O2·C6H 14 O3) n , with a molecular weight of 80,000 Da to 600,000 Da), polystyrene aerogel ((C8H8) n , with a molecular weight of 100,000 Da to 300,000 Da), polyimide aerogel ((C 22 H 10 N2O5) n , with a molecular weight of 50,000 Da to 200,000 Da), polyethylene aerogel ((C2H4) n , with a molecular weight of 60,000 Da to 2,000,000 Da), polyvinyl alcohol aerogel ((C2H4O) n , with a molecular weight of 20,000 Da to 200,000 Da) or polyacrylate aerogel ((C3H4O2) n , with a molecular weight of 100,000 Da to 1,000,000 Da), or at least one of them. By selecting the above porous aerogel materials, the porous aerogel can have appropriate thermal conductivity and porosity, and can better reduce the rate of increase in the temperature of the positive electrode sheet, thereby improving the thermal stability and safety performance of the electrochemical device.

[0034] In one embodiment of the present application, the particle size D v 50 of the porous aerogel is 0.1 μm to 2 μm. Exemplarily, D v 50 can be 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.0 μm or a range composed of any two of the above values. By regulating the particle size D v 50 of the porous aerogel within the above range, the particle size of the porous aerogel is moderate, the packing density increases, the density and uniformity of the functional layer are improved, and the heat dissipation performance of the functional layer can be better improved, thereby improving the thermal stability and safety performance of the electrochemical device.

[0035] In the present application, the particle size Dv50 of the porous aerogel refers to the particle size that reaches 50% of the cumulative volume from the small particle size side in the particle size distribution based on volume of the porous aerogel.

[0036] In one embodiment of the present application, the density of the porous aerogel is 1 kg / m 3 to 500 kg / m3 Exemplarily, the density of the porous aerogel can be 1 kg / m 3 、50 kg / m 3 、100 kg / m 3 、150 kg / m 3 、200 kg / m 3 、250 kg / m 3 、300 kg / m 3 、350 kg / m 3 、400 kg / m 3 、450 kg / m 3 、500 kg / m 3 or a range composed of any two of the above values. By adjusting the density of the porous aerogel within the above range, the porous aerogel has a lower density. Setting a porous aerogel that meets the above characteristics in the functional layer can reduce the weight of the electrochemical device without significantly increasing the volume of the electrochemical device, reduce the impact on the energy density of the electrochemical device, enable the electrochemical device to have both a high energy density and a lightweight characteristic layer, and at the same time ensure that the performance of the functional layer in thermal management is not lost, improving the thermal stability and safety performance of the electrochemical device.

[0037] In one embodiment of the present application, the coating porosity of the functional layer is 70% to 95%. Exemplarily, the coating porosity of the functional layer can be 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94%, 95% or a range composed of any two of the above values. In the functional layer, the porosity of the porous aerogel is 85% to 99%. By implanting a phase change heat absorption material or other functional materials in the porous aerogel and reducing the porosity of the functional layer to be within the above range, the heat conduction path can be better extended, the functional layer can better block the heat generated by the positive electrode sheet, and the thermal stability and safety performance of the electrochemical device can be improved.

[0038] In one embodiment of the present application, the hydrate includes at least one of sodium sulfate decahydrate (Na2SO4·10H2O), magnesium sulfate heptahydrate (MgSO4·7H2O), calcium chloride hexahydrate (CaCl2·6H2O) or zinc chloride hexahydrate (ZnCl2·6H2O); the fatty acid includes lauric acid (Lauric Acid, C 12 H 24 O2), stearic acid (Stearic Acid, C 18 H 36 O2), palmitic acid (Palmitic Acid, C 16 H 32 O2), myristic acid (Myristic Acid, C14 H 28 O2) or oleic acid (C 18 H 34 O2), etc. By selecting the above-mentioned saline compounds and fatty acids as the phase change heat absorption materials, the phase change heat absorption materials have good phase change heat absorption effects. When the operating temperature of the positive electrode sheet reaches or exceeds the phase change temperature, the rate of temperature rise of the positive electrode sheet can be reduced well, thereby improving the thermal stability and safety performance of the electrochemical device.

[0039] In an embodiment of the present application, the functional layer further includes inorganic nanoparticles, and the inorganic nanoparticles include at least one of titanium dioxide (TiO2), aluminum oxide (Al2O3), or ceramic particles. The ceramic particles may include at least one of aluminum oxide ceramic particles, zirconia ceramic particles, or silicon carbide ceramic particles. The particle size of the inorganic nanoparticles is D 1v 50, 5 nm < D 1v 50 < 200 nm. Exemplarily, D 1v 50 can be 6 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 199 nm, or a range composed of any two of the above values. Based on the total mass of the functional layer, the mass percentage content of the inorganic nanoparticles is 0% to 10%. Exemplarily, the mass percentage content of the inorganic nanoparticles can be 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or a range composed of any two of the above values. The functional layer may also include inorganic nanoparticles. When the above-mentioned inorganic nanoparticles are implanted into the porous aerogel, the porous aerogel can maintain its shape and function when subjected to external pressure, vibration, or impact, reduce the possibility of structural collapse or damage, and improve the mechanical support ability of the functional layer. The particle size and mass percentage content of the inorganic nanoparticles meet the above characteristics, which can reduce the influence of the inorganic nanoparticles on the porosity and heat dissipation performance of the functional layer while improving the mechanical support ability of the functional layer. Therefore, by setting inorganic nanoparticles in the functional layer, the functional layer can have good heat dissipation performance and mechanical support ability at the same time, improving the pressure resistance and safety performance of the electrochemical device.

[0040] In an embodiment of the present application, the functional layer further includes a porous adsorbent material, which includes at least one of zeolite or activated carbon; based on the total mass of the functional layer, the mass percentage of the porous adsorbent material is 0% to 10%. Exemplarily, the mass percentage of the porous adsorbent material can be 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or a range composed of any two of the above values. The functional layer may also include a porous adsorbent material. When the porous aerogel is implanted with the above porous adsorbent material, it can adsorb the excessive gas generated when the working temperature of the positive electrode plate reaches or exceeds the thermal runaway temperature, slow down the increase of the internal pressure of the electrochemical device, and at the same time absorb redox gases, reducing the possibility of heat generation caused by crosstalk between the positive electrode plate and the negative electrode plate, and reducing the heat accumulation of the electrochemical device. When the mass percentage of the porous adsorbent material meets the above range, it can absorb excessive gas while reducing the influence of the porous adsorbent material on the porosity and heat dissipation performance of the functional layer. Therefore, by setting the porous adsorbent material in the functional layer and making the type and content of the porous adsorbent material meet the above range, the thermal stability and safety performance of the electrochemical device can be improved.

[0041] In an embodiment of the present application, the functional layer further includes a functional conductive agent and a solid electrolyte. The functional conductive agent includes at least one of acetylene black or Ketjen black, and the solid electrolyte includes at least one of a polymer solid electrolyte or a ceramic solid electrolyte. Based on the total mass of the functional layer, the mass percentage of the functional conductive agent is 0% to 2%. Exemplarily, the mass percentage of the functional conductive agent can be 0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0% or a range composed of any two of the above values. The mass percentage of the solid electrolyte is 0% to 2%. Exemplarily, the mass percentage of the solid electrolyte can be 0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0% or a range composed of any two of the above values. The functional layer may also include a functional conductive agent and a solid electrolyte. By adding the above functional conductive agent and solid electrolyte during the preparation of the functional layer slurry and controlling their mass percentages to meet the above range, the functional layer can have the characteristics of improving the conductivity and ion transport performance of the electrochemical device while better blocking the heat generated by the positive electrode plate. When the content of the functional conductive agent or the solid electrolyte is too high, for example, greater than 2%, the content of the other components of the functional layer is less, which will affect the heat dissipation ability of the functional layer and reduce its performance of blocking the heat generated by the positive electrode plate. Therefore, by controlling the types and mass percentages of the functional conductive agent and the solid electrolyte in the functional layer to meet the above range, the thermal stability and safety performance of the electrochemical device can be improved while improving the conductivity and ion transport performance of the electrochemical device.

[0042] In one embodiment of the present application, the polymer solid electrolyte includes at least one of polyethylene oxide (PEO), polyacrylonitrile (PAN)-based electrolyte, polymethyl methacrylate (PMMA)-based electrolyte, polystyrene-polyethylene oxide (PS-PEO) block copolymer, or polyurethane (PU)-based electrolyte; the ceramic solid electrolyte includes at least one of yttrium-doped zirconia (YSZ), lithium sulfide (Li2S)-based compound, lithium phosphate (Li3PO4)-based compound, lithium titanate (Li4Ti5O 12 ) or Li7La3Zr2O 12 (LLZO). By regulating the type of the solid electrolyte within the above range, the functional layer can better improve the ion transport performance of the electrochemical device while not affecting the heat dissipation ability of the functional layer, and improve the thermal stability and safety performance of the electrochemical device.

[0043] In the present application, the functional layer further includes a binder and a dispersant. The present application does not particularly limit the types of the binder and the dispersant, as long as the purpose of the present application can be achieved. For example, the binder 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, polyamideimide, styrene-butadiene rubber, or polyvinylidene fluoride. For example, the dispersant may include, but is not limited to, at least one of polycarboxylate (PO), polyvinylpyrrolidone (PVP), and sodium carboxymethyl cellulose (CMC). The present application does not particularly limit the mass percentage content of the binder and the dispersant, as long as the purpose of the present application can be achieved. For example, the mass percentage content of the binder may be 1% to 2%, and the mass percentage content of the dispersant may be 1% to 2%.

[0044] In the present application, the thermal conductivity of the porous aerogel can be regulated by regulating the porosity of the porous aerogel. For example, when other conditions remain unchanged and the porosity of the porous aerogel increases, the thermal conductivity of the porous aerogel decreases. The porosity of the porous aerogel can be adjusted by adjusting the preparation process parameters (parameters such as precursor concentration, templates of different specifications, reaction conditions, etc.)

[0045] The density of the porous aerogel can be regulated by regulating the crosslinking density of the solid skeleton. For example, when other conditions remain unchanged and the crosslinking density of the solid skeleton increases, the density of the porous aerogel generally increases.

[0046] The coating porosity of the functional layer can be regulated by regulating the deposition rate of the coating material. For example, when other conditions remain unchanged and the deposition rate increases, the coating porosity of the functional layer decreases.

[0047] The present application relates to the particle size D of the inorganic nanoparticles 1vThere is no particular limitation on the regulation method of 50, as long as the purpose of this application can be achieved. For example, it can be achieved by screening and crushing.

[0048] In an embodiment of the present application, the functional layer includes a porous aerogel, a phase change heat absorption material, a binder, and a dispersant. Based on the total mass of the functional layer, the sum of the mass percentage contents of the porous aerogel and the phase change heat absorption material is 96% to 98%, the mass percentage content of the binder is 1% to 2%, and the mass percentage content of the dispersant is 1% to 2%.

[0049] In an embodiment of the present application, the functional layer includes a porous aerogel, a phase change heat absorption material, inorganic nanoparticles, a binder, and a dispersant. Based on the total mass of the functional layer, the sum of the mass percentage contents of the porous aerogel and the phase change heat absorption material is 86% to 97%, the mass percentage content of the inorganic nanoparticles is 1% to 10%, the mass percentage content of the binder is 1% to 2%, and the mass percentage content of the dispersant is 1% to 2%.

[0050] In an embodiment of the present application, the functional layer includes a porous aerogel, a phase change heat absorption material, a porous adsorption material, a binder, and a dispersant. Based on the total mass of the functional layer, the sum of the mass percentage contents of the porous aerogel and the phase change heat absorption material is 86% to 97%, the mass percentage content of the porous adsorption material is 1% to 10%, the mass percentage content of the binder is 1% to 2%, and the mass percentage content of the dispersant is 1% to 2%.

[0051] In an embodiment of the present application, the functional layer includes a porous aerogel, a phase change heat absorption material, a functional conductive agent, a solid electrolyte, a binder, and a dispersant. Based on the total mass of the functional layer, the sum of the mass percentage contents of the porous aerogel and the phase change heat absorption material is 92% to 96%, the mass percentage content of the functional conductive agent is 1% to 2%, the mass percentage content of the solid electrolyte is 1% to 2%, the mass percentage content of the binder is 1% to 2%, and the mass percentage content of the dispersant is 1% to 2%.

[0052] In an embodiment of the present application, the functional layer includes a porous aerogel, a phase change heat absorption material, inorganic nanoparticles, a functional conductive agent, a solid electrolyte, a binder, and a dispersant. Based on the total mass of the functional layer, the sum of the mass percentage contents of the porous aerogel and the phase change heat absorption material is 82% to 96%, the mass percentage content of the inorganic nanoparticles is 1% to 10%, the mass percentage content of the functional conductive agent is 1% to 2%, the mass percentage content of the solid electrolyte is 1% to 2%, the mass percentage content of the binder is 1% to 2%, and the mass percentage content of the dispersant is 1% to 2%.

[0053] In an embodiment of the present application, the functional layer includes a porous aerogel and a phase change heat absorption material, a porous adsorbent, a functional conductive agent, a solid electrolyte, a binder, and a dispersant. Based on the total mass of the functional layer, the sum of the mass percentages of the porous aerogel and the phase change heat absorption material is 82% to 96%, the mass percentage of the porous adsorbent is 1% to 10%, the mass percentage of the functional conductive agent is 1% to 2%, the mass percentage of the solid electrolyte is 1% to 2%, the mass percentage of the binder is 1% to 2%, and the mass percentage of the dispersant is 1% to 2%.

[0054] In an embodiment of the present application, the functional layer includes a porous aerogel and a phase change heat absorption material, inorganic nanoparticles, a porous adsorbent, a binder, and a dispersant. Based on the total mass of the functional layer, the sum of the mass percentages of the porous aerogel and the phase change heat absorption material is 80% to 96%, the mass percentage of the inorganic nanoparticles is 1% to 10%, the mass percentage of the porous adsorbent is 1% to 10%, the mass percentage of the binder is 1% to 2%, and the mass percentage of the dispersant is 1% to 2%.

[0055] In an embodiment of the present application, the functional layer includes a porous aerogel and a phase change heat absorption material, inorganic nanoparticles, a porous adsorbent, a functional conductive agent, a solid electrolyte, a binder, and a dispersant. Based on the total mass of the functional layer, the sum of the mass percentages of the porous aerogel and the phase change heat absorption material is 80% to 94%, the mass percentage of the inorganic nanoparticles is 1% to 10%, the mass percentage of the porous adsorbent is 1% to 10%, the mass percentage of the functional conductive agent is 1% to 2%, the mass percentage of the solid electrolyte is 1% to 2%, the mass percentage of the binder is 1% to 2%, and the mass percentage of the dispersant is 1% to 2%.

[0056] In an embodiment of the present application, the functional layer is disposed on the surface of the positive electrode plate adjacent to the separator or on the surface of the separator adjacent to the positive electrode plate. The setting position of the functional layer satisfies the above characteristics, which can simplify the preparation process and improve production efficiency. In some embodiments, when the functional layer is disposed on the surface of the positive electrode plate, after the phase change heat absorption material melts and changes from a solid state to a liquid state, it coats the positive active material on the surface of the positive electrode plate to a certain extent, reducing the heat generation of the positive electrode plate and blocking the rapid diffusion of the heat generated by the positive electrode plate; in other embodiments, when the functional layer is disposed on the surface of the separator, it can provide a gas channel, reduce the influence of gas, and reduce the heat generated by the interaction of the positive and negative electrode materials. Therefore, by regulating the setting position of the function to satisfy the above characteristics, the thermal stability and safety performance of the electrochemical device can be improved.

[0057] In this application, there is no particular limitation on the preparation method of the functional layer, as long as the purpose of this application can be achieved. For example, the preparation method of the functional layer may include but is not limited to the following steps: implanting a phase change heat absorption material into a porous aerogel, adding a binder and a dispersant, and stirring and dispersing in an N-methylpyrrolidone (NMP) solvent to form a functional layer slurry. Among them, based on the total mass of the functional layer slurry, the mass ratio of the porous aerogel, the phase change heat absorption material, the binder, and the dispersant is (23 to 72):(8 to 57):(1 to 2):(1 to 2).

[0058] In this application, the electrochemical device includes a positive electrode plate, and the positive electrode plate includes a positive electrode current collector and a positive electrode material layer provided on at least one surface of the positive electrode current collector. The above-mentioned "positive electrode material layer provided on at least one surface of the positive electrode current collector" means that the positive electrode material layer can be provided on one surface of the positive electrode current collector along its thickness direction, or can be provided on two surfaces of the positive electrode current collector along its thickness direction. It should be noted that the "surface" here can be the entire area of the positive electrode current collector surface or a partial area of the positive electrode current collector surface. There is no particular limitation in this application, as long as the purpose of this application can be achieved.

[0059] There is no particular limitation on the positive electrode current collector in this application, as long as the purpose of this application can be achieved. For example, it can include aluminum foil, aluminum alloy foil, or a composite current collector (such as an aluminum-carbon composite current collector), etc.

[0060] The positive electrode material layer includes a positive electrode active material. There is no particular limitation on the positive electrode active material in this application, as long as the purpose of this application can be achieved. For example, the positive electrode active material can include but is not limited to at least one of lithium nickel cobalt manganese oxide (such as NCM811, NCM622, NCM523, NCM111), lithium nickel cobalt aluminate, lithium iron phosphate, lithium-rich manganese-based material, lithium cobalt oxide (LiCoO2), lithium manganese oxide, lithium manganese iron phosphate, or lithium titanate.

[0061] The positive electrode material layer may further include a conductive agent and a binder. The present application does not particularly limit the types of the conductive agent and the binder, as long as the object of the present application can be achieved. For example, the conductive agent may include, but is not limited to, at least one of conductive carbon black (SuperP), carbon nanotubes (CNTs), carbon fibers, flake graphite, graphene, metal materials, or conductive polymers. The conductive carbon black may include, but is not limited to, at least one of acetylene black or Ketjen black. 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 nanofibers. The above-mentioned metal materials may include, but are not limited to, metal powders and / or metal fibers. 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. For example, the binder 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, polyamideimide, styrene-butadiene rubber, or polyvinylidene fluoride. The present application does not particularly limit the mass ratio of the positive electrode active material, the conductive agent, and the binder in the positive electrode material layer, and those skilled in the art can select according to actual needs as long as the object of the present application can be achieved.

[0062] The present application does not particularly limit the thicknesses of the positive electrode current collector and the positive electrode material layer, as long as the object of the present application can be achieved. For example, the thickness of the positive electrode current collector is 5 μm to 20 μm, and the thickness of the positive electrode material layer is 30 μm to 120 μm.

[0063] In the present application, the electrochemical device further includes a separator. The present application does not particularly limit the separator, as long as the object of the present application can be achieved. For example, the material of the separator may include, but is not limited to, at least one of polyethylene (PE), polyolefin (PO) based on polypropylene (PP), polyester (for example, polyethylene terephthalate (PET) film), cellulose, polyimide (PI), polyamide (PA), spandex, or aramid. The type of the separator may include, but is not limited to, at least one of a woven film, a non-woven film, a microporous film, a composite film, a calendared film, or a spun film.

[0064] In some embodiments of the present application, the separator may include a substrate layer and a surface treatment layer. The substrate layer may be a non-woven fabric, a film, or a composite film having a porous structure. The material of the substrate layer may include 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.

[0065] Optionally, a surface treatment layer is provided on at least one surface of the base material layer. The surface treatment layer can be a polymer layer, an inorganic layer, or a layer formed by mixing polymers and inorganic substances.

[0066] In some embodiments of the present application, the inorganic layer includes inorganic particles and a binder. There are no particular limitations on the inorganic particles in the present application. For example, the inorganic particles can include at least one of alumina, silica, magnesia, 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. There are no particular limitations on the binder in the present application. For example, the binder can be at least one of the above binders. In some embodiments of the present application, the polymer layer includes a polymer, and the materials of the polymer include at least one of polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyethylene ether, or polyvinylidene fluoride or poly(vinylidene fluoride - hexafluoropropylene).

[0067] In the present application, there are no particular limitations on the thickness of the separator, as long as the object of the present application can be achieved. For example, the thickness of the separator can be 3 μm to 30 μm.

[0068] In the present application, there are no particular limitations on the preparation method of the positive electrode sheet, as long as the object of the present application can be achieved. For example, in some embodiments of the present application, a functional layer is provided on the surface of the positive electrode sheet adjacent to the separator. The preparation method of the positive electrode sheet can include but is not limited to the following steps: (1) Preparation of a semi-finished positive electrode sheet: Add the positive electrode active material, conductive agent, and binder to N-methylpyrrolidone, stir and mix evenly to form a positive electrode slurry. Coat the positive electrode slurry evenly on one surface of the positive electrode current collector and then dry it. Then repeat the above steps on the other surface of the positive electrode current collector to obtain a semi-finished positive electrode sheet with a positive electrode material layer coated on both sides. (2) Preparation of the positive electrode sheet: Coat the functional layer on the surface of the semi-finished positive electrode sheet adjacent to the separator on one side by gravure roll transfer coating, and dry it to obtain the positive electrode sheet.

[0069] There are no particular limitations on the solid content of the positive electrode slurry in the present application, as long as the object of the present application can be achieved. There are no particular limitations on the above drying temperature in the present application, as long as the object of the present application can be achieved. For example, the drying temperature can be 90°C to 130°C.

[0070] The present application does not particularly limit the preparation method of the separator, as long as the object of the present application can be achieved. For example, in some embodiments of the present application, a functional layer is provided on the surface of the separator adjacent to the positive electrode plate. The preparation method of the separator may include, but is not limited to, the following steps: preparing a substrate, and applying the functional layer to the surface of the substrate adjacent to the positive electrode plate by gravure roll transfer coating, and drying in an oven at 45°C to 60°C to obtain the separator. Among them, the above substrate can also be obtained by purchase.

[0071] In the present application, the electrochemical device further includes a negative electrode plate, which includes a negative electrode current collector and a negative electrode material layer provided on at least one surface of the negative electrode current collector. The above "the negative electrode material layer is provided on at least one surface of the negative electrode current collector" means that the negative electrode material layer can be provided on one surface of the negative electrode current collector along its own thickness direction, or can be provided on both surfaces of the negative electrode current collector along its own thickness direction. It should be noted that the "surface" here can be the entire area of the surface of the negative electrode current collector, or a partial area of the surface of the negative electrode current collector. The present application does not particularly limit, as long as the object of the present application can be achieved.

[0072] The present application does not particularly limit the negative electrode current collector, as long as the object of the present application can be achieved. For example, it can include copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam or composite current collector. Exemplarily, the composite current collector can be a lithium-copper composite current collector, a carbon-copper composite current collector, a nickel-copper composite current collector, a titanium-copper composite current collector, etc.

[0073] The negative electrode material layer includes a negative electrode active material. The present application does not particularly limit the negative electrode active material, as long as the object of the present application can be achieved. For example, the negative electrode active material can include, but is not limited to, natural graphite, artificial graphite, mesophase microcarbon spheres, hard carbon, soft carbon, silicon, silicon-carbon composites, Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, SnO2, spinel-structured lithiated TiO2-Li4Ti5O 12 or at least one of Li-Al alloys.

[0074] In some embodiments of the present application, the negative electrode material layer may further include a conductive agent and a binder. The present application does not particularly limit the types of the conductive agent and the binder, as long as the object of the present application can be achieved. For example, it can be at least one of the above conductive agent and the above binder. The present application does not particularly limit the mass ratio of the negative electrode active material, the conductive agent, and the binder in the negative electrode material layer. Those skilled in the art can select according to actual needs, as long as the object of the present application can be achieved.

[0075] The present application does not particularly limit the thickness of the negative electrode current collector and the negative electrode material layer, as long as the object of the present application can be achieved. For example, the thickness of the negative electrode current collector is 4 μm to 15 μm, and the thickness of the negative electrode material layer is 30 μm to 120 μm.

[0076] In the present application, the electrochemical device further includes an electrolyte, and the electrolyte includes a lithium salt and a non-aqueous solvent.

[0077] The present application does not particularly limit the lithium salt, as long as the object of the present application can be achieved. For example, the lithium salt may include, but is not limited to, at least one of LiPF6, LiBF4, LiAsF6, LiClO4, LiB(C6H5)4, LiCH3SO3, LiCF3SO3, LiN(SO2CF3)2, LiC(SO2CF3)3, Li2SiF6, lithium bis(oxalato)borate (LiBOB), or lithium difluoroborate. The present application does not particularly limit the content of the lithium salt in the electrolyte, as long as the object of the present application can be achieved.

[0078] The present application does not particularly limit the non-aqueous solvent, as long as the object of the present application can be achieved. For example, the non-aqueous solvent may include, but is not limited to, at least one of carbonate compounds, carboxylate compounds, ether compounds, or other organic solvents.

[0079] The above-mentioned carbonate compounds may include, but are not limited to, at least one of linear carbonate compounds, cyclic carbonate compounds or fluorinated carbonate compounds. The above-mentioned linear carbonate compounds may include, but are not limited to, at least one of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC) or methyl ethyl carbonate (MEC). The above-mentioned cyclic carbonates may include, but are not limited to, at least one of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC) or vinylene ethylene carbonate (VEC). The fluorinated carbonate compounds may include, but are not limited to, at least one of fluorinated ethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate, 1,1,2,2-tetrafluoroethylene carbonate, 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-difluoro-1-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene carbonate or trifluoromethyl ethylene carbonate. The above-mentioned carboxylic ester compounds may include, but are not limited to, at least one of methyl formate, methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, γ-butyrolactone, decanolide, valerolactone or caprolactone. The above-mentioned ether compounds may include, but are not limited to, at least one of dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1-ethoxy-1-methoxyethane, 2-methyltetrahydrofuran or tetrahydrofuran. The above-mentioned other organic solvents may include, but are not limited to, at least one of dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate or trioctyl phosphate. The present application has no particular limitation on the content of the non-aqueous solvent in the electrolyte, as long as the object of the present application can be achieved.

[0080] The electrochemical device further includes a housing for accommodating the positive electrode sheet, the separator, the negative electrode sheet and the electrolyte, as well as other components known in the field of electrochemical devices. The present application does not limit the above-mentioned other components. The present application has no particular limitation on the housing, and it may be a housing well-known in the art, as long as the object of the present application can be achieved. For example, the housing may be a hard shell housing or a flexible housing. The material of the hard shell housing may be metal. The present application does not limit the type of metal, and a metal hard shell housing known in the art may be used, as long as the object of the present application can be achieved. The flexible housing may be a metal plastic film, such as an aluminum plastic film, a steel plastic film, etc.

[0081] The preparation process of the electrochemical device of the present application is well-known to those skilled in the art, and there is no special limitation in the present application. For example, the preparation process of the electrochemical device may include, but is not limited to, the following steps: stacking the positive electrode sheet, the separator and the negative electrode sheet in sequence, and winding, folding, etc. as required to obtain a wound electrode assembly, placing the electrode assembly into a housing, injecting an electrolyte into the housing and sealing it to obtain an electrochemical device. Alternatively, stack the positive electrode sheet, the separator and the negative electrode sheet in sequence, and then fix the four corners of the entire laminated structure with tape to obtain a laminated electrode assembly, place the electrode assembly into a housing, inject an electrolyte into the housing and seal it to obtain an electrochemical device. In addition, an overcurrent protection element, a guide plate, etc. can also be placed in the housing as needed to prevent the pressure inside the electrochemical device from rising and overcharging / discharging.

[0082] The second aspect of the present application provides an electronic device, which includes the electrochemical device in any of the foregoing embodiments. Therefore, the electronic device has good thermal stability and crush resistance safety performance.

[0083] The present application does not particularly limit the type of the electronic device, and it can be any electronic device known in the prior art. In some embodiments of the present application, the electronic device may include, but is not limited to, a laptop computer, a pen input computer, a mobile computer, an e-book player, a portable phone, a portable fax machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, a liquid crystal 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 source, a motor, an automobile, a motorcycle, a moped, a bicycle, a lighting fixture, a toy, a game console, a clock, a power tool, a flash, a camera, a large household battery, and a lithium-ion capacitor, etc.

[0084] Examples

[0085] Hereinafter, examples and comparative examples are given to illustrate the embodiments of the present application more specifically. Various tests and evaluations are carried out according to the following methods. In addition, unless otherwise specified, "parts" and "%" are based on mass.

[0086] Testing method and device:

[0087] Testing of the thermal conductivity of the porous aerogel:

[0088] After discharging the lithium-ion battery at a constant current of 0.1C to 3.0V, disassemble the lithium-ion battery to obtain the positive electrode plate or separator with the functional layer. Wash the positive electrode plate or separator with N-methylpyrrolidone (NMP), separate the functional layer from the positive electrode plate or separator, filter and dry it at 85°C to obtain the functional layer material powder. Heat the functional layer powder in an environment of 200°C for 120 minutes, then put it into a centrifuge (Beckman Coulter Avanti J-26XP) and centrifuge to obtain the porous aerogel powder. Compact the porous aerogel powder into a disc or block sample with a known density and thickness using a mold or press. Measure the thermal conductivity of the compacted sample using the heat flow meter method. Clamp the sample between two constant temperature plates and measure the heat flow and temperature difference passing through the sample. Thermal conductivity calculation formula: k = q*d / ΔT*A (k is the thermal conductivity of the material, unit: watt per meter per kelvin (W / m·K). q is the heat flow passing through the sample, unit: watt (W). A is the cross-sectional area of the sample, unit: square meter (m 2 ). ΔT is the temperature difference between both sides of the sample, unit: kelvin (K). d is the thickness of the sample, unit: meter (m).

[0089] Porous aerogel density test:

[0090] After discharging the lithium-ion battery at a constant current of 0.1C to 3.0V, disassemble the lithium-ion battery to obtain the positive electrode plate or separator with the functional layer. Wash the positive electrode plate or separator with N-methylpyrrolidone (NMP), separate the functional layer from the positive electrode plate or separator, filter and dry it at 85°C to obtain the functional layer material powder. Heat the functional layer material powder in an environment of 200°C for 120 minutes, then put it into a centrifuge (Beckman Coulter Avanti J-26XP) and centrifuge to obtain the porous aerogel powder. After measuring the mass of the sample by taking part of the porous aerogel powder as the sample, put the sample into a pycnometer and measure the displaced gas volume: By measuring the gas volume displaced by the sample, obtain the volume of the sample, and then obtain the density.

[0091] Particle size test:

[0092] After discharging the lithium-ion battery at a constant current of 0.1C to 3.0V, disassemble the lithium-ion battery to obtain the positive electrode plate or separator with the functional layer. Wash the positive electrode plate or separator with N-methylpyrrolidone (NMP), separate the functional layer from the positive electrode plate or separator, filter and dry it at 85°C to obtain the functional layer material powder. Disperse the functional layer material powder into deionized water or alcohol, add sodium hexametaphosphate dispersant, stir ultrasonically for 10 minutes, and use a Malvern particle size analyzer (model MasterSizer2000) to test the above functional layer material powder to obtain the particle sizes of each component, such as the particle size Dv50 of the porous aerogel.

[0093] Porosity Test of Functional Layer:

[0094] After discharging the lithium-ion battery at a constant current of 0.1C to 3.0V, disassemble the lithium-ion battery to obtain the positive electrode plate or separator with the functional layer. Wash the positive electrode plate or separator with N-methylpyrrolidone (NMP), separate the functional layer from the positive electrode plate or separator, filter, and dry at 85°C to obtain the functional layer material powder. Use a scanning electron microscope (SEM) to observe the microstructure of the functional layer material, and calculate the porosity through image analysis software.

[0095] Hot Box Performance Test:

[0096] Under the condition of 25°C, put the lithium-ion battery charged at a constant current of 2C to 4.5V and then charged at a constant voltage of 4.5V until the current is 0.02C into a test chamber with circulating air convection, a temperature of 25°C, and a humidity of 80%. After standing for 5 minutes, heat the test chamber at a rate of 5°C / min to 135°C, keep it at 135°C unchanged, stop the test after 10 minutes, and check whether the lithium-ion battery catches fire or explodes. Take 20 lithium-ion batteries for each group of examples and comparative examples for testing. Passing the test means no fire or explosion. The passing rate of the 135°C hot box test = the number of lithium-ion batteries passing the hot box test at 135°C / the total number of lithium-ion batteries in the hot box test at 135°C (20). Characterize the hot box performance of the lithium-ion battery by the passing rate of the 135°C hot box test.

[0097] Crushing Critical Stress Test:

[0098] After discharging the lithium-ion battery at a constant current of 0.1C to 3.0V, use a three-point bending testing machine (Instron 5900 series). This device usually includes two support points and a indenter for applying load. The distance between the support points and the shape of the indenter are adjusted according to the size of the lithium-ion battery and the test standard. Place the lithium-ion battery sample horizontally on the two support points, with the middle part of the lithium-ion battery directly below the indenter, and apply a gradually increasing pressure of 20N / min to the lithium-ion battery. When the lithium-ion battery shows obvious deformation, rupture, leakage, or other forms of failure and the lithium-ion battery fails to return to its original shape after unloading; or the lithium-ion battery shows permanent bending or warping, it is regarded as the collapse of the lithium-ion battery. At this time, the pressure is the maximum load at which the lithium-ion battery begins to collapse or be damaged. The crushing critical stress value of the lithium-ion battery can be calculated through the formula σc = Fc / A. Among them, Fc is the maximum load causing material damage or collapse, and A is the cross-sectional area where the load acts.

[0099] Example 1-1

[0100] <Preparation of Functional Layer Slurry>

[0101] Paraffin phase change heat absorption material is implanted into silica aerogel, and binder polyvinylidene fluoride and dispersant polyvinylpyrrolidone (PVP) are added. N-methylpyrrolidone (NMP) is added as a solvent, and stirring and dispersion are carried out to form a functional layer slurry. Among them, based on the total mass of the functional layer slurry, the mass ratio of silica aerogel, paraffin material, binder and dispersant is 56:42:1:1. Among them, the mass percentage content of the porous aerogel is denoted as W1, the mass percentage content of the phase change heat absorption material is denoted as W2, the mass percentage content of the binder is denoted as W X , and the mass percentage content of the dispersant is denoted as W Y .

[0102] <Preparation of positive electrode sheet>

[0103] The positive electrode active material LiCoO2, binder polyvinylidene fluoride and conductive agent Super P are mixed according to the mass ratio of 97.6:1.3:1.1, and N-methylpyrrolidone (NMP) is added as a solvent to prepare a slurry with a solid content of 75 wt%. After vacuum stirring evenly, a positive electrode slurry is obtained. The positive electrode slurry is evenly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 10 μm and dried at 120 °C to obtain a semi-finished positive electrode sheet with a single-sided coated positive electrode material layer. Then, the above steps are repeated on the other surface of the aluminum foil to obtain a semi-finished positive electrode sheet with a double-sided coated positive electrode material layer. After drying at 120 °C, cold pressing is carried out, and then slitting and welding the tabs are carried out to obtain a semi-finished positive electrode sheet with a specification of 74 mm × 867 mm for standby. Among them, the thickness of the single-sided positive electrode material layer is 40 μm, and the coating weight of the single-sided positive electrode material layer is 210 mg / 1540 mm 2 . The prepared functional layer slurry is evenly coated on the positive electrode material layer adjacent to the separator of the positive electrode sheet, and after drying at 120 °C, a positive electrode sheet is obtained. Among them, the thickness of the functional layer is 3 μm.

[0104] <Preparation of negative electrode sheet>

[0105] The negative electrode active material silicon, binder styrene-butadiene rubber and conductive agent acetylene black are mixed according to the mass ratio of 97.4:1.4:1.2, and deionized water is added as a solvent to prepare a slurry with a solid content of 45 wt%. After vacuum stirring evenly with a vacuum mixer, a negative electrode slurry is obtained. The negative electrode slurry is evenly coated on one surface of a negative electrode current collector copper foil with a thickness of 6 μm and dried at 120 °C to obtain a negative electrode sheet with a single-sided coated negative electrode material layer. Then, the above steps are repeated on the other surface of the copper foil to obtain a negative electrode sheet with a double-sided coated negative electrode material layer. After drying at 120 °C, cold pressing is carried out, and then slitting and welding the tabs are carried out to obtain a negative electrode sheet with a specification of 78 mm × 875 mm for standby. Among them, the thickness of the single-sided negative electrode material layer is 35 μm, and the coating weight of the single-sided negative electrode material layer is 90 mg / 1540 mm2 .

[0106] <Preparation of Electrolyte>

[0107] In an environment where the water content is less than 10 ppm, dimethyl carbonate, diethyl carbonate, and ethylene carbonate are mixed in a mass ratio of 1:1:1 to obtain an organic solvent, and then lithium salt LiPF6 is added to the organic solvent and mixed evenly to obtain an electrolyte. The mass percentage of the lithium salt is 12.5% ​​based on the mass of the electrolyte, and the rest is the organic solvent.

[0108] <Diaphragm>

[0109] A polyethylene porous film with a thickness of 8 μm was used as the separator.

[0110] <Preparation of lithium-ion batteries>

[0111] The positive electrode sheet, the separator, and the negative electrode sheet are stacked in order, so that the separator is placed between the positive electrode sheet and the negative electrode sheet to play an isolating role, and the electrode assembly is wound, and the electrode assembly is placed in an aluminum plastic film packaging bag, and the moisture is removed at 80°C, and the prepared electrolyte is injected, and the lithium-ion battery is obtained after vacuum packaging, standing, forming, and shaping. Among them, the upper limit voltage of the formation is 4.53V, the formation temperature is 85°C, and the formation time is 50min.

[0112] Example 1-2 to Example 1-17

[0113] Except for adjusting the relevant preparation parameters in <Preparation of Functional Layer Slurry> and <Preparation of Positive Electrode Sheet> according to Table 1, the rest is the same as Example 1-1.

[0114] Example 2-1 to Example 2-28

[0115] Except that at least one of inorganic nanoparticles, porous adsorption materials, functional conductive agents and / or solid electrolytes is implanted in the porous aerogel material according to Table 2 in the preparation of functional layer slurry, and the relevant preparation parameters are adjusted, the rest is the same as Example 1-1. Among them, the mass percentage of inorganic nanoparticles is recorded as W3, the mass percentage of porous adsorption materials is recorded as W4, the mass percentage of functional conductive agents is recorded as W5, and the mass percentage of solid electrolytes is recorded as W6.

[0116] Example 2-29

[0117] Except for adjusting the relevant preparation parameters in <Preparation of positive electrode sheet> and <Separator> according to the following steps, the rest is the same as Example 1-1.

[0118] <Preparation of positive electrode sheet>

[0119] The positive electrode active material LiCoO₂, the binder polyvinylidene fluoride, and the conductive agent Super P are mixed in a mass ratio of 97.6:1.3:1.1, and N-methylpyrrolidone (NMP) is added as a solvent to prepare a slurry with a solid content of 75 wt%. After vacuum stirring evenly, the positive electrode slurry is obtained. The positive electrode slurry is uniformly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 10 μm, and dried at 120 °C to obtain a positive electrode sheet with a single-sided coated positive electrode material layer. Then, the above steps are repeated on the other surface of the aluminum foil to obtain a positive electrode sheet with a double-sided coated positive electrode material layer. After drying at 120 °C, it is cold-pressed, and then cut and welded with electrode tabs to obtain a positive electrode sheet with a specification of 74 mm × 867 mm for use. Among them, the thickness of the single-sided positive electrode material layer is 40 μm, and the coating weight of the single-sided positive electrode material layer is 210 mg / 1540 mm 2 。

[0120] <Separator>

[0121] A polyethylene porous film with a thickness of 8 μm is used as the separator. The prepared functional layer slurry is uniformly coated on the surface of the separator adjacent to the positive electrode sheet, and after drying at 120 °C, a separator with a functional layer is obtained for use. Among them, the thickness of the functional layer is 3 μm.

[0122] Comparative Example 1

[0123] Except for preparing a positive electrode sheet without a functional layer according to the following steps, the rest is the same as in Example 1-1

[0124] <Preparation of positive electrode sheet>

[0125] The positive electrode active material LiCoO₂, the binder polyvinylidene fluoride, and the conductive agent Super P are mixed in a mass ratio of 97.6:1.3:1.1, and N-methylpyrrolidone (NMP) is added as a solvent to prepare a slurry with a solid content of 75 wt%. After vacuum stirring evenly, the positive electrode slurry is obtained. The positive electrode slurry is uniformly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 10 μm, and dried at 120 °C to obtain a positive electrode sheet with a single-sided coated positive electrode material layer. Then, the above steps are repeated on the other surface of the aluminum foil to obtain a positive electrode sheet with a double-sided coated positive electrode material layer. After drying at 120 °C, it is cold-pressed, and then cut and welded with electrode tabs to obtain a positive electrode sheet with a specification of 74 mm × 867 mm for use. Among them, the thickness of the single-sided positive electrode material layer is 40 μm, and the coating weight of the single-sided positive electrode material layer is 210 mg / 1540 mm 2 。

[0126] Comparative Examples 2 to 6

[0127] Except for adjusting the relevant preparation parameters according to Table 1 in the preparation of the functional layer slurry and the preparation of the positive electrode sheet, the rest is the same as in Example 1-1.

[0128]

[0129]

[0130] It can be seen from Examples 1-1 to 1-17 and Comparative Examples 1 to 6 that in the positive electrode sheet and separator of the lithium-ion battery in the embodiments of the present application, there is directly a functional layer including a porous aerogel and a phase change heat absorption material, and by controlling the thermal conductivity of the porous aerogel, the thickness of the functional layer, and the total mass percentage content of the phase change heat absorption material and the porous aerogel within the scope of the present application, the lithium-ion battery can have a high passing rate of the 135 °C hot box test and a high critical stress value of crushing, indicating that the lithium-ion battery in the embodiments of the present application has good thermal stability and safety performance and crush resistance safety performance. The lithium-ion battery in Comparative Example 1 does not contain a functional layer; the thermal conductivity of the porous aerogel in Comparative Example 2 is not within the scope of the present application; the thickness of the functional layer in Comparative Examples 3 to 4 is not within the scope of the present application; the total mass percentage content of the phase change heat absorption material and the porous aerogel in Comparative Examples 5 to 6 is not within the scope of the present application; at this time, the passing rate of the 135 °C hot box test of the lithium-ion battery in the comparative example is relatively low, and / or the critical stress value of crushing is relatively low. It shows that the lithium-ion batteries in Comparative Examples 1 to 6 have poor thermal stability and safety performance and crush resistance safety performance.

[0131] The mass percentage content of the porous aerogel and the mass percentage content of the phase change heat absorption material will affect the thermal stability and safety performance and crush resistance safety performance of the lithium-ion battery. It can be seen from Examples 1-1, 1-6 to 1-11 that when the mass percentage content of the porous aerogel and the mass percentage content of the phase change heat absorption material are controlled within the scope of the present application, the lithium-ion battery can have a high passing rate of the 135 °C hot box test, and / or a high critical stress value of crushing, indicating that the lithium-ion battery provided in the embodiments of the present application has good thermal stability and safety performance and crush resistance safety performance.

[0132]

[0133]

[0134]

[0135] The particle size of the porous aerogel affects the thermal stability safety performance and the crush resistance safety performance of the lithium-ion battery. As can be seen from Example 1-1 and Examples 2-1 to 2-3, when the particle size of the porous aerogel is adjusted within the scope of this application, the lithium-ion battery can have a high passing rate in the 135°C hot box test and / or a high crush critical stress value, indicating that the lithium-ion battery provided by the embodiments of this application has good thermal stability safety performance and crush resistance safety performance.

[0136] The density of the porous aerogel affects the thermal stability safety performance and the crush resistance safety performance of the lithium-ion battery. As can be seen from Example 1-1 and Examples 2-4 to 2-6, when the density of the porous aerogel is adjusted within the scope of this application, the lithium-ion battery can have a high passing rate in the 135°C hot box test and / or a high crush critical stress value, indicating that the lithium-ion battery provided by the embodiments of this application has good thermal stability safety performance and crush resistance safety performance.

[0137] The functional layer may further include inorganic nanoparticles. The type and particle size of the inorganic nanoparticles affect the thermal stability safety performance and the crush resistance safety performance of the lithium-ion battery. As can be seen from Examples 2-7 to 2-11, when the type and particle size of the inorganic nanoparticles are adjusted within the scope of this application, the lithium-ion battery can have a high passing rate in the 135°C hot box test and / or a high crush critical stress value, indicating that the lithium-ion battery provided by the embodiments of this application has good thermal stability safety performance and crush resistance safety performance.

[0138] The functional layer may further include inorganic nanoparticles. The mass percentage content of the inorganic nanoparticles affects the thermal stability safety performance and the crush resistance safety performance of the lithium-ion battery. As can be seen from Examples 2-7 and Examples 2-12 to 2-13, when the mass percentage content of the inorganic nanoparticles is adjusted within the scope of this application, the lithium-ion battery can have a high passing rate in the 135°C hot box test and / or a high crush critical stress value, indicating that the lithium-ion battery provided by the embodiments of this application has good thermal stability safety performance and crush resistance safety performance.

[0139] The functional layer may further include a porous adsorbent material. The type and mass percentage content of the porous adsorbent material affect the thermal stability safety performance and the crush resistance safety performance of the lithium-ion battery. As can be seen from Examples 2-14 to 2-17, when the type and mass percentage content of the porous adsorbent material are adjusted within the scope of this application, the lithium-ion battery can have a high passing rate in the 135°C hot box test and / or a high crush critical stress value, indicating that the lithium-ion battery provided by the embodiments of this application has good thermal stability safety performance and crush resistance safety performance.

[0140] The functional layer may also include a functional conductive agent and a solid electrolyte. The types and mass percentage contents of the functional conductive agent and the solid electrolyte will affect the thermal stability and safety performance and the crush resistance and safety performance of the lithium-ion battery. It can be seen from Examples 2-18 to 2-21 that when the types and mass percentage contents of the functional conductive agent and the solid electrolyte are adjusted within the scope of this application, the lithium-ion battery can have a high passing rate in the 135°C hot box test and / or a high critical stress value for crush, indicating that the lithium-ion battery provided by the embodiments of this application has good thermal stability and safety performance and crush resistance and safety performance.

[0141] The composition and mass percentage content of each component in the functional layer will affect the thermal stability and safety performance and the crush resistance and safety performance of the lithium-ion battery. It can be seen from Examples 1-1, 2-22 to 2-28 that when the composition and mass percentage content of each component in the functional layer are adjusted within the scope of this application, the lithium-ion battery can have a high passing rate in the 135°C hot box test and / or a high critical stress value for crush, indicating that the lithium-ion battery provided by the embodiments of this application has good thermal stability and safety performance and crush resistance and safety performance.

[0142] The coating porosity of the functional layer will affect the thermal stability and safety performance and the crush resistance and safety performance of the lithium-ion battery. It can be seen from Examples 2-1 to 2-29 that when the coating porosity of the functional layer is adjusted within the scope of this application, the lithium-ion battery can have a high passing rate in the 135°C hot box test and / or a high critical stress value for crush, indicating that the lithium-ion battery provided by the embodiments of this application has good thermal stability and safety performance and crush resistance and safety performance.

[0143] The coating position of the functional layer will affect the thermal stability and safety performance and the crush resistance and safety performance of the lithium-ion battery. It can be seen from Examples 1-1, 2-29 that when the coating position of the functional layer is adjusted within the scope of this application, the lithium-ion battery can have a high passing rate in the 135°C hot box test and / or a high critical stress value for crush, indicating that the lithium-ion battery provided by the embodiments of this application has good thermal stability and safety performance and crush resistance and safety performance.

[0144] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method or article including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method or article.

[0145] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments.

[0146] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the scope of protection of the present application.

Claims

1. An electrochemical device, comprising a positive electrode sheet, a negative electrode sheet and a separator, wherein a functional layer is provided between the positive electrode sheet and the separator, wherein the functional layer comprises a porous aerogel and a phase change endothermic material, wherein the thermal conductivity of the porous aerogel is 0.01 W / (m·k) to 0.05 W / (m·k); the porous aerogel comprises at least one of silicon aerogel, metal oxide aerogel, polymer aerogel and carbon aerogel; the phase change endothermic material comprises at least one of gallium alloy, indium tin alloy, paraffin, salt hydrate or fatty acid; the thickness of the functional layer is 1 μm to 5 μm; Based on the total mass of the functional layer, the total mass percentage of the phase change heat absorption material and the porous aerogel is 80% to 98%.

2. The electrochemical device according to claim 1, wherein: Based on the total mass of the functional layer, the mass percentage of the phase change heat absorption material is 8% to 57%, and the mass percentage of the porous aerogel is 23% to 72%.

3. The electrochemical device according to claim 1, wherein The metal oxide aerogel is selected from at least one of titanium oxide aerogel, aluminum oxide aerogel, zirconium oxide aerogel or magnesium oxide aerogel; the polymer aerogel is selected from at least one of aramid aerogel, polyurethane aerogel, polystyrene aerogel, polyimide aerogel, polyethylene aerogel, polyvinyl alcohol aerogel or polyacrylate aerogel.

4. The electrochemical device according to claim 1, wherein The particle size D of the porous aerogel v 50 is 0.1μm to 2μm.

5. The electrochemical device according to claim 1, wherein The density of the porous aerogel is 1 kg / m 3 Up to 500kg / m 3 .

6. The electrochemical device according to claim 1, wherein The coating porosity of the functional layer is 70% to 95%.

7. The electrochemical device according to claim 1, wherein: The salt hydrate includes at least one of sodium sulfate decahydrate, magnesium sulfate heptahydrate, calcium chloride hexahydrate or zinc chloride hexahydrate; the fatty acid includes at least one of lauric acid, stearic acid, palmitic acid, myristic acid or oleic acid.

8. The electrochemical device according to claim 1, wherein The functional layer further comprises inorganic nanoparticles, wherein the inorganic nanoparticles comprise at least one of titanium dioxide, aluminum oxide or ceramic particles, and the particle size of the inorganic nanoparticles is D 1v 50,5nm<D 1v 50<200nm; Based on the total mass of the functional layer, the mass percentage of the inorganic nanoparticles is 0% to 10%.

9. The electrochemical device according to claim 1, wherein: The functional layer further comprises a porous adsorption material, wherein the porous adsorption material comprises at least one of zeolite or activated carbon; based on the total mass of the functional layer, the mass percentage of the porous adsorption material is 0% to 10%.

10. The electrochemical device according to claim 1, wherein The functional layer also includes a functional conductive agent and a solid electrolyte, the functional conductive agent includes at least one of acetylene black or Ketjen black, the solid electrolyte includes at least one of a polymer solid electrolyte or a ceramic solid electrolyte, and based on the total mass of the functional layer, the mass percentage of the functional conductive agent is 0% to 2%; the mass percentage of the solid electrolyte is 0% to 2%.

11. The electrochemical device according to claim 10, wherein: The polymer solid electrolyte includes at least one of polyethylene oxide, polyacrylonitrile-based electrolyte, polymethyl methacrylate-based electrolyte, polystyrene-polyethylene oxide block copolymer or polyurethane-based electrolyte; the ceramic solid electrolyte includes zirconium oxide doped with yttrium, lithium sulfide-based compound, lithium phosphate-based compound, lithium titanate or Li7La3Zr2O 12 At least one of .

12. The electrochemical device according to any one of claims 1 to 10, wherein: The functional layer is arranged on the surface of the positive electrode plate adjacent to the separator or on the surface of the separator adjacent to the positive electrode plate.

13. An electronic device, wherein: The electronic device comprises the electrochemical device according to any one of claims 1 to 12.

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