129 results about "Skin effect" patented technology

This invention relates to the application of electromagnetic shielding composite materials, specifically to an electromagnetic shielding composite film with a gradient structure and its preparation method. Using a polymer film as the core layer, electromagnetic functional layers are sequentially deposited on both sides of the polymer core layer, and a carbon fiber felt is composited on at least one side, resulting in an electromagnetic shielding composite film with excellent electromagnetic shielding performance. The gradient multilayer structure design of this invention utilizes the principles of impedance mismatch at different interfaces and the skin effect to effectively improve the multiple reflections of electromagnetic waves between different functional layers. Furthermore, the type of polymer core layer can be changed according to different needs; using a polymer-based high-barrier film as the core layer can yield a high-barrier electromagnetic shielding packaging film that combines high barrier properties with high electromagnetic shielding.

This invention provides a leadframe packaging method and structure, relating to the field of chip packaging technology. First, a leadframe is provided. Then, wire bonding is applied to the front side of each first pseudo-pin to form a first connecting arc, achieving electrical connection between multiple first pseudo-pins and / or multiple connecting pins. Next, an adhesive layer is formed on the back side of the connecting frame, and the chip is mounted on the leadframe. Then, a molding compound is formed on the front side of the connecting frame. The adhesive layer is removed, a stepped groove is formed, and finally, a back gold layer is formed. Compared to existing technologies, this invention improves the adhesive bonding strength of the adhesive layer, effectively reducing the risk of adhesive layer detachment during molding, thereby reducing the risk of back adhesive overflow contamination during molding. Furthermore, it mitigates the skin effect during electroplating, improving electroplating quality and process efficiency, resulting in better electroplating quality and higher process efficiency.

The present application relates to the technical field of magnetron sputtering target recovery, and discloses a method for efficient recovery of a diffusion welding target using an electromagnetic induction heating technology. For the diffusion welding target using pure aluminum or an aluminum alloy as an intermediate layer, an electromagnetic induction alternating current is applied to the aluminum intermediate layer, and on the basis of the skin effect of the alternating current, a target blank and the aluminum intermediate layer are rapidly heated in the form of an eddy current. Due to the relatively low melting point, the aluminum intermediate layer can be rapidly heated above the melting point and melted, such that the target blank is separated from the aluminum intermediate layer. Finally, aluminum residues on the surface of the target blank are removed by means of machining turning, and cleaning and drying are carried out, to obtain a high-purity target blank that can be recycled. By employing rapid electromagnetic induction heating, the present application can effectively improve recovery efficiency and economic benefits while ensuring the purity of the target surface, and is environmentally friendly and pollution-free during the recovery process, and can be widely applied to 8-inch and 12-inch targets containing an aluminum intermediate layer.

The present application relates to a kind of heat treatment processes for improving H13 mandrel impact energy, comprising the following steps: after forging ultrafine treatment, medium frequency quenching, first tempering, second tempering, after forging heat treatment adopts ultrafine treatment process, eliminates reticular structure, obtains good spheroidizing structure, prepares good organizational condition for subsequent quenching and tempering, performance heat treatment adopts medium frequency quenching and tempering, because medium frequency induction coil heating is carried out by skin effect, heating speed is fast, grain is more fine, product heating and cooling stress is small, product straightness is good, using the heat treatment mode of after forging ultrafine treatment+medium frequency quenching and tempering can make the refining steel diameter≤φ200mm specification mandrel obtain higher strength and good impact energy, better solve the problem of low impact energy of H13 mandrel forgings below specification ≤φ200mm of vacuum refining steel production using conventional heat treatment process, meet product design and use requirement, under the premise of strength satisfying design requirement, room temperature average impact energy KV2≥20J.

The utility model relates to the technical field of cables, in particular to a feed cable for a maglev train, which comprises a conductor. The outer wall of the conductor is coated with the semi-conductive wrapping layer; the insulating layer is extruded on the outer wall of the semi-conductive wrapping layer; the semi-conductive shielding layer is coated on the outer wall of the insulating layer; and the braided shielding layer is coated on the outer wall of the semi-conductive shielding layer. According to the utility model, the inner layer of the conductor is a circular stranded conductor, the outer layer is a fan-shaped stranded conductor, impedance rise caused by skin effect can be reduced, the insulating layer is a double-layer insulating layer, the inner layer adopts a high-density polyethylene structure, and the outer layer adopts a gradient foaming structure, so that the skin depth of high-frequency current can be effectively reduced, and the service life of the cable is prolonged. In addition, the low dielectric constant foaming layer also reduces the eddy current loss of the shielding layer, the overall thermal stability of the cable is improved, and higher current-carrying capacity can be realized.

The application provides a kind of flat wire motor full slot technology of hairpin multi-wire motor stator, which adopts the topology process of end edge greater than effective edge section, realizes "full slot" (refers to equivalent resistance), and the coil resistance is 30% lower than that of X-pin and Hair-pin process motor.In the two-layer flat wire structure, the same specification of 8 turns of special-shaped wire is filled in the slot hole in self-adaptive sliding fit with trapezoidal slot, and the bundle with central cooling hole is formed. One hairpin element occupies a position to realize 16 layers of wire layout to reduce skin effect and improve motor power density and efficiency. The two ends of the hairpin center hole are connected by sealed pipeline, and cooling medium is injected for heat dissipation. The ineffective edges of the hairpin element with multiple enlarged sections are connected to phase lines by the effective edges and the end edges with multiple enlarged sections respectively to realize equivalent resistance as full slot to meet the market demand of electric motorcycle, E-bike, electric motorcycle, new energy and electric vehicle.

The utility model relates to a power module, a control system and a vehicle. The power module comprises a conductive part and a plurality of power chips arranged on the conductive part. Wherein the conductive part is provided with a first side and a second side, the extension direction of the first side is the same as the arrangement direction of the plurality of power chips, an included angle is formed between the extension direction of the first side and the extension direction of the second side, and the included angle is larger than 0 degree and smaller than 90 degrees. The included angle is formed between the extension directions of the first side and the second side, so that the width of the conductive part is in a gradual change state to adapt to current in different areas, and the width change of the conductive part is obtained by extending the included angle formed by the first side and the second side, so that the width of the conductive part does not suddenly change in the width change process of the conductive part; and the first edge and the second edge do not have corner angle structures caused by width change, so that the skin effect of the first edge and the second edge is effectively avoided, the current path is smoother, and the current is prevented from being locally gathered to cause local overheating.

The invention discloses a boron carbide composite ceramic tool bit and a preparation method thereof. The boron carbide composite ceramic tool bit comprises a tool bit body and a welding transition body, the tool bit body is internally provided with a boron carbide ceramic framework with a three-period minimal curved surface topological structure, three-dimensional communicating holes of the framework are filled with a metallic bond and diamond abrasive particles, and the welding transition body is a pure metallic bond transition layer. A hard wear-resistant phase is arranged on the outer surface of the combination body. The method comprises the following steps: constructing a boron carbide ceramic skeleton with a pore surface micro-nano diversion trench through additive manufacturing, and depositing an electromagnetic sensitive phase; injecting the powder into the three-dimensional communicated pores and assembling a green body; applying mechanical oscillation pressure and a high-frequency alternating electromagnetic field at the sintering temperature, and inducing an in-situ metallurgical reaction by utilizing local joule heat generated by a skin effect to finish densification sintering; and a surface hard wear-resistant phase is generated through chemical heat treatment or component in-situ reaction. Compact interlocking of the internal structure is achieved, the service life of the tool bit is prolonged, and the welding strength of the tool bit is improved.

The present application provides a kind of method for extracting the frequency domain impedance characteristics of grounding grid under the impact of intermediate frequency oscillation, belongs to the technical field of grounding grid operation and maintenance, the present application establishes the three-dimensional geometric model of grounding grid and uses the fractal dimension adaptive grid generation algorithm to divide the grid in the conductor area, establishes the multi-layer soil complex permittivity model to characterize the frequency variation characteristics of soil electromagnetic parameters, decomposes the intermediate frequency impact excitation signal into multiple narrowband components and inputs the artificial intelligence impedance characteristic extraction model based on neural tangent kernel theory, calculates the current density distribution and electromagnetic field distribution under different frequency points, extracts the skin effect depth and adjacent effect coupling coefficient, constructs the frequency response function of grounding grid and identifies the distribution position of resonance frequency point, adaptively adjusts the grid density parameters and iterative convergence precision parameters according to the ionization degree of soil, solves the problem that the frequency domain impedance characteristics of grounding grid under the condition of intermediate frequency impact are difficult to accurately extract.

A non-invasive biosignal measurement device based on skin effect removal, includes: a signal measurement instrument measuring a PPG signal of a measurement subject in contact with the skin on one side of a specific body part of the measurement subject; a signal reception unit receiving the PPG signal from the signal measurement instrument; and a ratio value calculation unit removing noise due to a skin effect from the PPG signal, and then calculating ratio values at different wavelengths for measuring a biosignal including blood sugar and glycated hemoglobin of the measurement subject. The signal measurement instrument includes a first sensor module including an optical barrier and a second sensor module for removing the skin effect.

The application discloses a MOFs-derived high-entropy alloy / carbon composite wave-absorbing material, which has a structure of a plurality of connected cluster structures; the cluster structures are composed of a plurality of connected porous hollow spherical structures; the porous hollow spherical structures are formed by accumulation of nanometer spherical particles; and the nanometer spherical particles are composed of amorphous carbon and FeCoNiCuCr high-entropy alloy nanoparticles uniformly distributed therein. The application also provides a preparation method of the MOFs-derived high-entropy alloy / carbon composite wave-absorbing material. Through component design of a MOFs precursor and carbonization process regulation, the high-entropy alloy is uniformly distributed in the carbon skeleton of the MOFs derivative, the skin effect caused by large-particle magnetic particles is effectively avoided, the electromagnetic wave loss capacity is improved, and the wave-absorbing performance is effectively improved. Meanwhile, the prepared wave-absorbing material has relatively small density, and the preparation process is simple.

The utility model provides a kind of polygonal core wire and high-speed cable, polygonal core wire includes single-core conductor and the insulating layer being arranged in single-core conductor outside, the cross section of single-core conductor is polygonal.High-speed cable, including several side-by-side arranged core wire, and the shielding layer being covered in the core wire outside, the core wire is polygonal core wire.In the case where equivalent consumables, increase the cross section perimeter of conductor, weaken skin effect, reduce power loss, reduce the impedance of cable.

The invention discloses an underground magnetic distance measurement detection method, system and device and a storage medium, and the method comprises the steps: applying excitation to a transmitting antenna, generating an induced magnetic field in a stratum space, and generating an eddy current on the surface of a metal medium of a metal part in a target well; receiving a secondary induced magnetic field generated by eddy current of the metal part in the target well through a receiving antenna and a compensation antenna which are formed by forward and reverse winding of a wire; and the distance and the orientation of the target well are obtained through the received induced magnetic field intensity in combination with spatial magnetic field response feature inversion. Due to the skin effect, attenuation of propagation of electromagnetic waves in a high-resistance stratum environment is slow, the underground magnetic distance measurement detection method based on electromagnetic induction can still detect strong magnetic field response information, and good distance measurement performance is guaranteed. According to the magnetic distance measurement detection method, the diversity and complexity of the geological environment to be detected can be improved, higher flexibility and adaptability are achieved for different mining environments, and the distance measurement precision of the area nearby the target well is improved.

The invention belongs to the technical field of microwave communication, and particularly discloses a low-loss differential transmission line structure based on a common dielectric layer. According to the invention, the technical means of alternately laminating multiple transmission layers and dielectric layers and arranging through holes for vertical interconnection is adopted, so that an electromagnetic field is distributed in the air above and below the conductor as much as possible, and the side surface of the signal transmission conductor is grooved, so that the dielectric loss of the substrate is directly reduced; signal transmission conductors are connected through high-density metalized through holes, so that signal current can flow in parallel in a plurality of metal layers through the through holes, the equivalent cross sectional area of current circulation is remarkably increased under the high-frequency skin effect, the equivalent resistivity is reduced, and the conductor loss is reduced; meanwhile, the grounding conductors are connected in parallel through the through holes, an electromagnetic field is bound around the signal transmission conductor, and radiation loss and mutual interference are restrained to the maximum extent. Compared with the prior art, the effects of greatly reducing high-frequency loss and improving signal integrity on a common dielectric layer are achieved.

This suppresses the decrease in current measurement accuracy caused by the skin effect. [Solution] The current sensor comprises a shield having an opening for taking in a magnetic field generated by a current flowing through a conductor, a magnetic field sensor disposed inside the shield and outputting a sensor voltage corresponding to the magnetic field at that location, and a detection circuit disposed outside the shield and detecting a current based on the sensor voltage of the magnetic field sensor, wherein the magnetic field sensor includes a first magnetic field sensor for detecting low-frequency magnetic fields and a second magnetic field sensor for detecting high-frequency magnetic fields, the first magnetic field sensor being disposed closer to the opening than the second magnetic field sensor, and the second magnetic field sensor being disposed further from the opening than the first magnetic field sensor.

The application provides a PCB transformer, a design method, a DC / DC converter and a power module, wherein the design method comprises the following steps: determining the single-turn winding width based on the window size of a magnetic core; determining the branch winding width based on the transformer center frequency and the winding material parameters, and determining the single-turn branch number based on the single-turn winding width and the branch winding width; determining the number of single-turn branch windings of the primary side and the secondary side based on the transformer type and the single-turn branch number to determine the transverse stagger mode, and determining the longitudinal stagger mode based on the turn difference of the primary side and the secondary side; designing the branch windings of the primary side and the secondary side in parallel based on the number of single-turn branch windings of the primary side and the secondary side, and stagger designing each single-turn winding of the primary side and the secondary side based on the transverse and longitudinal stagger modes to obtain a PCB winding plate. The application solves the problems of the existing single-turn copper PCB transformer, such as being greatly affected by the skin effect and the proximity effect, and having large parasitic capacitance and leakage inductance of the primary side and the secondary side.

The design and manufacturing method of the split winding is characterized by the separate design of the in-slot winding and the end winding, which breaks away from the constraints of traditional processes. This allows for complete freedom in the manufacturing process of the in-slot winding and the end winding, enabling the use of diverse configurations and processes. It simplifies the process, saves copper materials, and improves performance. Trapezoidal or irregularly shaped slots can be used to maximize the slot fill factor while ensuring magnetic flux density distribution. At the same time, the in-slot and out-of-slot windings can be designed with more layers to improve the skin effect, enhance temperature resistance, reduce the axial dimension of the end winding, and lower costs.

The application relates to the technical field of electric connectors, and discloses an elastic terminal and an electric connector. The elastic terminal comprises a first part, an elastic part and a second part. In a first direction, the first part and the second part are respectively connected to two sides of the elastic part. When the elastic terminal is compressed in the first direction, the first part and the second part are in contact with each other, forming two parallel current paths. Both the two parallel current paths bypass the elastic part, significantly reducing the equivalent resistance of the current conduction path, relieving the heating problem of the elastic terminal under a large-current working condition, and improving the current transmission efficiency and the connection reliability. In a high-speed signal transmission working condition, due to the skin effect of high-speed signals, both the two parallel current paths bypass the elastic part, significantly shortening the signal transmission path, effectively relieving the crosstalk and attenuation problems of high-frequency signals.

The invention relates to the technical field of acoustics, in particular to a non-Hermitian higher order Dirac semimetal structure for realizing an acoustic skin effect, which is composed of structural units arranged in a three-dimensional periodic array. Each structural unit comprises a plurality of acoustic cavities and acoustic coupling pipes connected with the acoustic cavities; the acoustic coupling tube is configured to provide intracellular coupling, intercellular coupling and interlayer coupling so as to construct a topological parent phase of the high-order Dirac semimetal; an acoustic loss unit is arranged in an acoustic cavity at a preset position in the structural unit; the acoustic loss unit introduces a non-Hermite imaginary term in the Hamiltonian of the structural unit. According to the invention, the acoustic skin effect is realized at a three-dimensional high order, and the device is simple in structure, is easy to control, and is high in robustness.

The utility model discloses a novel energy storage inductor which comprises a support and an inductor body installed on the support. The inductor body comprises a magnetic core, a first winding and a second winding, wherein the first winding and the second winding are wound on the magnetic core. The first winding and the second winding are formed by winding flat wires, two pins of the first winding penetrate through the support to form a first weld leg and a second weld leg, and two pins of the second winding penetrate through the support to form a third weld leg and a fourth weld leg. The flat wire energy storage inductor has the advantages of being low in skin effect, high in current bearing capacity and large in heat dissipation area, has more obvious advantages in large-current application occasions, and can achieve automatic operation, improve production efficiency and reduce product cost. The double-winding technology can be compatible with applications of different parameters in a larger range, the use under large-current and high-voltage occasions is met, the compatibility is high, the coverage is wide, and the advantages are obvious.

The application provides a kind of ultra-light stable phase radio frequency coaxial cable, including sequentially arranged from inside to outside in cross-sectional direction inner conductor, insulating layer, outer conductor, shielding isolation layer and outer protective layer;Inner conductor adopts Ag / FEP composite material, and conductive silver layer floats on the surface of fluoroplastic FEP;Outer conductor adopts Ag / PI / Ag composite material, and conductive silver layer is distributed around polyimide to form airtight conductive layer;Shielding isolation layer is woven shielding structure formed by weaving polyimide fiber with surface silver layer, and the surface of single polyimide fiber in it is covered with surface silver layer, and outer protective layer is FEP / PI / FEP outer protective layer or PFA outer protective layer.The ultra-light stable phase radio frequency coaxial cable provided by the application uses the principle of skin effect of high frequency signal, uses composite material containing surface silver layer, and uses non-metallic material with smaller density to replace metal material not participating in signal transmission part, reduces material weight on the basis of ensuring signal transmission demand, and reduces cable weight by more than 50%.

The invention relates to the technical field of vacuum coating, in particular to a vacuum coating device comprising a vaporizing chamber, a heat source device and a gas uniformizing device. The heat source device adopts double induction coils with current frequency difference to perform composite heating on the crucible, and the high-frequency skin effect and the low-frequency penetration effect are combined to realize rapid and uniform evaporation of materials. Vapor flow distribution is accurately regulated and controlled through dynamic local shielding, and the problems that in the prior art, due to the fact that heating inside and outside a linear evaporation source crucible is uneven, evaporation of internal materials is unstable, meanwhile, point heat sources are in point-shaped eruption, divergence angles are overlapped, the thickness of an evaporation film is uneven, and the evaporation effect is poor are solved. And the evaporation effect is poor.

The utility model discloses a transformer winding structure, which relates to the technical field of transformers, and comprises a magnetic core, a main winding and an auxiliary winding, the main winding is wound on the periphery of the magnetic core in a single-layer fitting manner by adopting a single-strand multi-core wire, the auxiliary winding is wound on the periphery of the main winding side by side by adopting N-strand multi-core wires, and N is an integer greater than or equal to two. According to the utility model, the main winding adopts the single-strand multi-core wire, under the condition of the same cross section area, the number of turns of the single-strand winding is less than that of the multi-strand winding, and the inductance is correspondingly reduced, so that the alternating-current impedance is reduced, and the energy conversion performance of the transformer is improved; according to the secondary winding, N strands of multi-core wires are adopted, under the condition of the same cross sectional area, compared with a single strand, the multi-strand wires increase the conductor surface area through which current flows, loss caused by the skin effect can be remarkably reduced, meanwhile, the current density is effectively dispersed, and the heat dissipation capacity is improved. The secondary winding is wound on the periphery of the main winding, mutual inductance interference between the secondary winding and the main winding can be effectively reduced, energy loss is reduced, and the energy conversion efficiency is further improved.

The invention belongs to the technical field of laser additive manufacturing, and discloses a high-frequency pulse current hot wire assisted titanium alloy laser coaxial fuse wire additive manufacturing method. Comprising the following steps: 1, preprocessing; 2, constructing a dual-module pulse hot wire system and setting a process window: constructing a laser coaxial fuse system, and introducing a high-frequency pulse hot wire power supply of a parallel dual-module topological structure into a wire feeding path; 3, metallographic phase preparation and structure evaluation; 4, testing mechanical properties; and step 5, parameter optimization based on'defect-structure-performance 'three-stage screening. Controlled high-frequency pulse current is applied in the wire feeding process, dendritic crystal growth is actively broken through the skin effect, transient thermal shock and high-frequency Lorentz force generated by the high-frequency pulse current, the nucleation rate in a molten pool is increased, and therefore columnar crystal orientation equiaxed crystal transformation (CET) is promoted, and a titanium alloy component with excellent isotropy is obtained.

The invention discloses a high-efficiency hybrid copper-aluminum rotor motor, which belongs to the technical field of motors and comprises a stator and a rotor, and a shell with radiating fins and an end cover are arranged on the outer side of the stator. The core improvement of the rotor is that the conducting bars are formed by mixing copper conducting bars and aluminum conducting bars and are arranged in a specific layered mode, the copper conducting bars are arranged on the upper layer and the lower layer of a rotor groove, the aluminum conducting bars are arranged on the middle layer, the skin effect is actively utilized, a high-frequency current path is optimized, and the copper conducting bars and the aluminum conducting bars are reliably and electrically connected at the end of the rotor through a conductive connecting ring. The connection process adopts a step-by-step different process method of firstly welding the copper conducting bar at a high temperature and then welding or crimping the aluminum conducting bar at a low temperature, and plating treatment can be selectively carried out on the end part of the aluminum conducting bar, so that the problems of reliability and durability of dissimilar metal connection are effectively solved. According to the invention, through collaborative design of materials and structures, the cost is greatly reduced while the efficiency of the motor is remarkably improved (the efficiency level can reach IE4 and above), and the process is stable and suitable for large-scale production.

The present application relates to the technical field of coils, and specifically relates to a coil unit, a coil winding, and a magnetic component. The coil unit comprises a plurality of planar coils formed by winding strip conductors; each planar coil comprises a coil body, and a first connection segment and a second connection segment which are connected to two ends of the coil body in a winding direction; the plurality of planar coils are stacked in the thickness direction of the strip conductors; each two adjacent planar coils are spaced apart to form a heat dissipation channel. By means of the heat dissipation channels, the heat exchange coefficient of the coil unit, the coil winding and the magnetic component can be increased, thereby reducing temperature rises. The first connection segments of all the planar coils are connected, and the second connection segments of all the planar coils are connected, so as to reduce the skin effect and the resistance of the coil unit while ensuring good contact between end portions of the multi-layer planar coils, thereby reducing the loss of coil windings and magnetic components, and helping to improve the reliability of the coil windings and the magnetic components.

The utility model discloses a thermal field structure for growing silicon carbide single crystals, which comprises a thermal insulation seat body, a side wall heating mechanism and a bottom heating mechanism, a crucible is arranged in the thermal insulation seat body, and the side wall heating mechanism is arranged between the thermal insulation seat body and the side wall of the crucible. A resistance-type heating bottom heating mechanism is arranged between the heat preservation seat body and the bottom of the crucible; the side wall heating mechanism comprises a plurality of sections of induction heating units which are sequentially arranged from top to bottom and are different in conductivity, and an induction coil is correspondingly arranged on the outer side of the heat preservation seat body. Through cooperation of the side wall heating mechanism and the bottom heating mechanism, the regulation and control range of the axial temperature gradient of liquid in the crucible is expanded; and the problem of insufficient bottom heating caused by a skin effect is avoided through a resistance-type heating bottom heating mechanism, so that the bottom of the crucible is fully and uniformly heated, the radial temperature gradient of liquid in the crucible is reduced, the crystal stress is reduced, the high-quality growth of crystals is realized, and relatively good practicability is achieved.

The application discloses an electrode for electric spark machining of a micro-hole with a large depth-diameter ratio and a preparation method thereof, and belongs to the technical field of tool electrode preparation. The electrode comprises a tungsten wire rod, and the diameter of the tungsten wire rod is 0.1-0.4 mm. The tungsten wire rod is characterized in that a uniform and stable zirconium oxide insulation layer is arranged on the peripheral wall of the tungsten wire rod. The electrode selects the stable zirconium oxide layer as the insulation layer, which can enhance the insulation property of the peripheral wall of the electrode. On one hand, the electrode can reduce the discharge removal between the peripheral wall of the electrode and the side wall of the hole in the electric spark machining process, thereby improving the forming precision of the micro-hole. On the other hand, the electrode can reduce the skin effect of the current in the electrode and increase the current density of the center of the end surface of the electrode. Meanwhile, the end surface of the insulation layer has the conductivity in the electric spark discharge, electric spark discharge is generated to remove the material, and the electric spark machining efficiency is improved.

The invention relates to the technical field of grounding device design, and discloses a graphene coating thickness determination method, system, equipment, medium and product, and the method comprises the steps: determining the skin depth under high-frequency current according to the conductance parameter of a graphene coating in combination with the lightning current frequency, and determining the thickness of the graphene coating under the constraint of the skin depth. And determining the optimal thickness of the graphene coating according to the conductivity parameter of the coated substrate and the conductivity parameter of the graphene coating in combination with the target impedance, so that the graphene coating can effectively utilize the skin effect to concentrate the current in a high-conductivity region under the action of high-frequency lightning current, and the condition that the coating covers the current concentration region to meet the conductive requirement is ensured; the impedance matching can be realized by adjusting the thickness of the coating, the inductance effect influence is considered, the total impedance is ensured not to exceed the limit value, and the overall conductivity is ensured to reach the standard.

A detection device according to the present disclosure is a detection device for detecting a status of a lithium-ion secondary battery, the detection device including a control module that acquires real part of AC impedance at a frequency at which the real part of the AC impedance is increased 10 times or more than the real part of the AC impedance at 1 KHz due to a skin effect, and that detects deposition of lithium and / or the presence of foreign metal inside the lithium-ion secondary battery by using the acquired real part of the AC impedance.