Wireless charging preform based on directional magnetic transmission and application thereof

Abstract

The application discloses a wireless charging prefabricated base based on directional magnetic transmission and application thereof. The prefabricated base comprises a concrete base, a magnetic concentrating layer, a stress buffer layer and a wireless charging unit. The wireless charging unit, as a core module, comprises a magnetic conducting layer, a coil packaging heat conducting layer and a heat storage layer. The relative magnetic permeability of the magnetic concentrating layer is less than or equal to 2.0. The elastic modulus of the stress buffer layer is 50MPa-500MPa. The relative magnetic permeability of the magnetic conducting layer is 50 times more than that of the magnetic concentrating layer. Through the cooperative design of the multifunctional layer, the application realizes efficient directional transmission of the magnetic field, active management of the heat and long-term durability of the structure.

Description

Technical Field

[0001] This invention belongs to the field of road engineering and transportation infrastructure technology, and more specifically, relates to a wireless charging prefabricated substrate based on directional magnetic transmission and its preparation method. Background Technology

[0002] Wireless charging technology uses a primary coil to generate an alternating magnetic field under alternating current, which induces a current in a secondary coil, thus enabling contactless power transfer to electric vehicles. Currently, the mainstream wireless charging embedding technologies mainly include two types: static parking charging and dynamic wireless charging. Static parking charging involves embedding charging pads in the ground or road surface of a parking space. The vehicle automatically charges using electromagnetic induction or magnetic resonance technology while parked, eliminating the need for cables. However, it only works when the vehicle is stationary and cannot address range anxiety while driving. Dynamic wireless charging technology typically embeds the primary coil in the road surface, enabling "charging while driving" compared to wired charging. Furthermore, the road structure can mitigate the adverse effects of traffic loads and environmental factors.

[0003] Patent CN120401310A discloses a road surface adapted to a magnetic resonance dynamic wireless charging system. This method employs on-site layered paving and sequential construction, resulting in complex procedures, long construction periods, and significant challenges in quality control. The interfacial bonding strength between functional layers is significantly affected by the on-site environment, easily leading to problems such as interlayer debonding, air bubbles, and localized defects. If the coil or encapsulation layer fails, the road surface must be milled and repaved, resulting in high repair costs, prolonged road closures, and severe disruption to traffic operations. Patent CN120967765A discloses a wireless charging prefabricated road surface using precast concrete pavement substrates. While this solves the problems of long on-site construction periods and difficult quality control, it still suffers from the following significant drawbacks in its transition to engineering applications: First, in terms of electromagnetics, conventional road materials and structures cannot guide magnetic fields, nor can they effectively guide or constrain them, resulting in diverging magnetic field lines, high magnetic circuit losses, low transmission efficiency, and spatial magnetic leakage, which may pose electromagnetic exposure risks to the surrounding environment and organisms.

[0004] Secondly, regarding thermal management, the Joule heat generated during coil operation tends to accumulate within the road surface structure. Especially in scenarios involving prolonged continuous charging or high-frequency charging, the heat cannot be dissipated in time, leading to excessively high local temperatures. High temperatures accelerate the aging and softening of asphalt materials, causing defects such as rutting and swelling. They also reduce the insulation life of the encapsulation materials and coils, severely impacting the long-term stability of the wireless charging road system.

[0005] Third, in terms of mechanics, the large difference in modulus between the embedded coil and the road surface material leads to significant interlayer thermal stress due to the mismatch in thermal expansion coefficients under repeated traffic loads and seasonal temperature changes. This can result in interface peeling, debonding, or even structural damage, significantly shortening the service life of the road. Summary of the Invention

[0006] To address the aforementioned technical deficiencies or improvement needs, this invention provides a wireless charging prefabricated substrate based on directional magnetic transmission and its preparation method. The aim is to achieve directional constraint of the magnetic field and suppression of magnetic leakage by setting a magnetically conductive layer and a magnetically bounding layer, employing a permeability difference of tens of times between the two layers. The high-permeability magnetically conductive layer guides the magnetic field upwards, while the low-permeability magnetically bounding layer constrains the lateral divergence of the magnetic field. This solves the technical problem of high roadside magnetic leakage and low transmission efficiency in existing wireless charging technologies.

[0007] To achieve the above objectives, according to a first aspect of the present invention, a prefabricated substrate for wireless charging based on directional magnetic transmission is provided, employing an electromagnetic induction charging method. It comprises, from the outside in, a concrete base with a pre-sized mounting groove, a magnetic confinement layer, a stress protection layer, and a wireless charging unit. The wireless charging unit is disposed within the mounting groove of the concrete base. The stress protection layer is uniformly coated on the bottom and surrounding sides of the wireless charging unit. A non-magnetic material is cast into the gap between the stress protection layer and the mounting groove of the concrete base to form a magnetic confinement layer, which is used to constrain the magnetic field, enabling the electromagnetic energy to be directionally transmitted upwards and reducing lateral magnetic leakage. The relative permeability of the magnetic flux layer is ≤2.0; the elastic modulus of the stress protection layer is 50MPa~500MPa; The wireless charging unit comprises, from top to bottom, a magnetic conductive layer, a coil encapsulation heat-conducting layer, and a heat storage layer; the magnetic conductive layer has a relative permeability of more than 50 times that of the magnetic coil layer; the coil encapsulation heat-conducting layer is formed by encapsulating the transmitting coil with insulating material; the heat storage layer includes a phase change core material and a supporting carrier.

[0008] Preferably, the wireless charging prefabricated substrate has a magnetic bead layer made of non-magnetic concrete with a thickness of 60mm-100mm; and a stress protection layer with a thickness of 20mm-40mm, which is made of high viscoelastic polysulfide sealant or flexible epoxy resin mortar sealant.

[0009] Preferably, the wireless charging prefabricated substrate is used for the construction, renovation and upgrading of wireless charging pavement structure in urban bus lanes, wherein the magnetic bundle layer has a thickness of 70mm-95mm, a relative magnetic permeability of 1.0-2.0, and a compressive strength ≥C40. More preferably, the stress protection layer has a thickness of 30mm-40mm and uses a high-viscosity SBS and rubber composite modified asphalt mortar with an elastic modulus of 150±30MPa, an elongation at break ≥220%, and a coefficient of thermal expansion of (22±4)×10. -6 / K.

[0010] Preferably, the wireless charging prefabricated substrate is used for the maintenance and upgrading of wireless charging pavement structures in parking spaces of highway service areas, and the magnetic flux layer has a thickness of 60mm-80mm and a relative magnetic permeability of 1.0-1.5. More preferably, the stress protection layer has a thickness of 20-35mm, is sealed with flexible epoxy resin mortar, has an elastic modulus of 350±50MPa, an elongation at break ≥160%, and a coefficient of thermal expansion of (18±3)×10. -6 / K.

[0011] Preferably, the wireless charging prefabricated substrate is used in heavy-duty transportation channels inside logistics parks, port terminals, etc., and the magnetic bead layer has a thickness of 100-130mm, a thermal conductivity of 1.7±0.2W / (m·K), and a relative magnetic permeability of 1.4±0.2. More preferably, the stress protection layer has a thickness of 35-45mm, is sealed with flexible epoxy resin mortar, has an elastic modulus of 80±30MPa, an elongation at break of ≥280%, and a coefficient of thermal expansion of (25±5)×10. -6 / K.

[0012] Preferably, in the wireless charging prefabricated substrate, the top of the wireless charging unit is a magnetic conductive layer with a thickness of 20mm-40mm, the middle is a coil encapsulation heat-conducting layer with a thickness of 25mm-35mm, and the bottom is a heat storage layer with a thickness of 30mm-60mm. The heat storage layer is formed by filling a phase change core material into a support carrier. The phase change core material includes paraffin wax with a phase change temperature of 50℃-70℃ and a latent heat of phase change of ≥150kJ / kg. The support carrier includes one or more of high-density polyethylene, cement substrate, and silicone rubber matrix.

[0013] Preferably, the wireless charging prefabricated substrate has a magnetic permeability of 50-100 times that of the magnetic bead layer, and includes AC-13C dense-graded asphalt mixture with manganese-zinc ferrite particles, concrete with manganese-zinc ferrite particles, or SMA-13 ​​mixture with ferrite particles.

[0014] According to a second aspect of the present invention, a method for preparing a wireless charging preform as described herein is also provided, comprising the following steps: (1) Prepare concrete base: pour concrete material according to the mold of the preset size, and reserve power wiring hole to form an upward-opening "U" shaped groove to obtain concrete base; (2) Preparation of wireless charging unit: fill phase change core material into support carrier to form heat storage layer, place transmitting coil on heat storage layer, encapsulate and solidify transmitting coil with insulating material to form coil encapsulation heat conduction layer; lay magnetic conductive layer of preset thickness on coil encapsulation heat conduction layer, and solidify these three layers to form an integral wireless charging unit. (3) Applying a stress protection layer: Apply stress protection layer material evenly to the bottom and surrounding sides of the obtained wireless charging unit; the stress protection layer material includes high viscoelastic polysulfide sealant or flexible epoxy resin mortar sealant. (4) Integral molding: After the stress protection layer is surface dry, place it in the center of the "U" shaped groove made in step (1), pour non-magnetic material into the gap between the two to form a magnetic bundle layer, cure and shape to obtain the wireless charging prefabricated substrate; the non-magnetic material includes concrete material with a relative magnetic permeability ≤2.0. For example, use 1 part of (P.O42.5 grade) cement, 2.8 to 3.0 parts of limestone coarse aggregate, 1.7 to 1.8 parts of limestone fine aggregate, 0.45 parts of water and 0.008 to 0.012 parts of polycarboxylate superplasticizer to make a magnetic bundle layer with a relative magnetic permeability of 1.0-2.0 and a compressive strength ≥C40.

[0015] Preferably, in the preparation method, step (2) of the phase change core material includes paraffin wax with a phase change temperature of 50℃-70℃ and a latent heat of phase change ≥150kJ / kg; the support carrier includes one or more of high-density polyethylene, cement substrate, and silicone rubber matrix.

[0016] Preferably, in the preparation method, the magnetic conductive layer is selected from AC-13C dense-graded asphalt mixture with manganese-zinc ferrite particles, concrete with manganese-zinc ferrite particles, or SMA-13 ​​mixture with ferrite particles.

[0017] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: (1) The wireless charging prefabricated substrate provided by the present invention adopts a design with a magnetic permeability difference of tens of times between the magnetic permeability of the magnetic permeable layer and the magnetic bundle layer. The magnetic field is guided to transmit upward through the high magnetic permeability magnetic permeable layer and constrained to disperse laterally through the low magnetic permeability magnetic bundle layer. Without the need for additional shielding devices, the magnetic field is directionally constrained and leakage is suppressed. This can solve the problems of low transmission efficiency, high roadside leakage, and poor electromagnetic environment safety of existing wireless charging road surfaces due to the lack of magnetic field guidance and constraint.

[0018] (2) The present invention also adopts a collaborative design of coil encapsulation heat conduction layer and phase change heat storage layer. It can quickly conduct Joule heat of transmitting coil through high thermal conductivity encapsulation material and absorb thermal shock and suppress temperature rise by using phase change material. It can solve the problems of accelerated thermal aging of asphalt material, high temperature softening of road surface and frequent rutting disease caused by heat accumulation in existing wireless charging road surfaces, as well as poor system thermal stability in long-term continuous charging scenarios.

[0019] (3) The present invention also employs a stress protection layer, which absorbs vehicle impact loads and coordinates the thermal expansion difference between the coil encapsulation layer and the magnetic bead layer, thereby reducing interlayer thermal stress. This can solve the problem that existing wireless charging pavements suffer from interface peeling, debonding, or even structural damage under traffic loads and temperature cycles due to the mismatch between the modulus and thermal expansion coefficient of the rigid coil and the pavement material. This results in a shortened service life.

[0020] (4) The present invention adopts a factory prefabrication integrated molding process, which prefabricates the magnetic conductive layer, coil encapsulation heat conductive layer, heat storage layer, magnetic bundle layer, stress protection layer and concrete base into standard modular blocks. On-site installation only requires grooving, hoisting and joint treatment. In case of single block failure, it can be replaced independently without large-area milling. It can solve the problems of existing embedded wireless charging pavement, which have complex on-site layered construction procedures, difficult quality control, high maintenance costs and long road closure time, resulting in high construction and maintenance costs and poor project feasibility. Attached Figure Description

[0021] Figure 1 This is a schematic cross-sectional view of the prefabricated substrate structure for wireless charging. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Current wireless charging technologies aim to reduce magnetic leakage and increase the magnetic coupling coefficient (k), thereby reducing transmission losses. This is primarily achieved by adding manganese-zinc ferrite ceramic sheets to the back of the coil in an array arrangement, or by using conductive metals such as copper and aluminum to suppress the magnetic field through eddy current shielding. This mechanism uses the reverse magnetic field generated by eddy currents induced in the conductive material to suppress the external magnetic field, and is commonly used as a shielding shell. However, ferrite ceramic sheets generate a significant amount of heat under alternating magnetic fields, and the eddy current shielding mechanism introduces additional eddy current losses.

[0024] This invention provides a prefabricated substrate for wireless charging based on directional magnetic transmission, employing electromagnetic induction charging. It comprises, from the outside in, a concrete base with a pre-sized mounting groove, a magnetic flux layer, a stress protection layer, and a wireless charging unit (as the core template). The wireless charging unit contains a transmitting coil and is positioned within the mounting groove of the concrete base. The stress protection layer is uniformly coated on the bottom and surrounding sides of the wireless charging unit. A non-magnetic material is poured into the gap between the stress protection layer and the mounting groove of the concrete base to form the magnetic flux layer, which constrains the magnetic field, directing electromagnetic energy upwards and reducing lateral magnetic leakage. The non-magnetic material can be selected from ordinary silicate cement mortar, unreinforced concrete, asphalt, modified asphalt, asphalt mastic, epoxy mortar, basalt aggregate, etc.

[0025] The concrete base is an upward-opening "U"-shaped groove with a pre-drilled power wiring hole for connecting to a high-frequency power input line. The relative permeability of the magnetic flux layer is ≤2.0, and the relative permeability of the magnetic conductive layer is more than 50 times that of the magnetic flux layer; the elastic modulus of the stress protection layer is 50MPa~500MPa.

[0026] In this invention, the difference in magnetic permeability between the magnetic conductive layer and the magnetic bead layer, which is tens of times, is used to form a directional transmission path in which "magnetic lines of force preferentially travel to the magnetic conductive layer". The magnetic lines of force preferentially go to the region with high magnetic permeability, which produces a directional transmission effect that "forces" the magnetic lines of force to gather upward rather than diffuse laterally.

[0027] If the entire concrete base (which is large in volume) is made of magnetic flux layer material, the material cost will increase significantly. However, in this invention, the magnetic flux layer is a thin layer (60-120mm thick, surrounding only the core module of the wireless charging unit) on the inner wall of a "U" shaped groove. The magnetic flux layer only needs to be poured around the core module, which is small in volume, requires less material, and has a low cost.

[0028] Furthermore, the concrete base needs to be thick (30-50mm) and high-strength, while the thickness of the magnetic flux layer can be flexibly adjusted according to the application scenario (60-120mm) and does not require high strength. If the two are combined into one, the structural design will be mutually restrictive: either the outer shell will be too thick and wasteful, or the strength of the magnetic flux layer will be insufficient. It is impossible to customize the design for different scenarios.

[0029] The wireless charging unit, as the core module, comprises, from top to bottom, a magnetic conductive layer, a coil encapsulation heat-conducting layer, and a heat storage layer. The relative permeability of the magnetic conductive layer is 50-100 times that of the magnetic bundle layer. The coil encapsulation heat-conducting layer is formed by encapsulating the transmitting coil with insulating material. In some embodiments, the coil encapsulation heat-conducting layer is formed by encapsulating the transmitting coil with insulating material having a thermal conductivity higher than 1.5 W / (m·K). The transmitting coil includes a double D-type Litz coil. The size of the transmitting coil matches the receiving end (under the vehicle). Under a high-frequency alternating magnetic field of 20-100 kHz (typically 85 kHz), the electric vehicle can be considered stationary. The receiving coil is located in the high-frequency alternating magnetic field generated by the transmitting coil. Due to the change in magnetic flux over time, according to Faraday's law of electromagnetic induction, an induced alternating electromotive force (or induced alternating current) is generated inside the receiving coil.

[0030] The thermal storage layer includes a phase change core material and a supporting carrier. The phase change core material includes thermal storage materials with a phase change temperature of 50℃-70℃ and a latent heat of phase change of ≥150kJ / kg, such as paraffin wax. The supporting carrier includes one or more of high-density polyethylene, cement substrate, and silicone rubber matrix.

[0031] While directly embedding the transmitting coil into the phase change material can achieve a shorter heat transfer path, some phase change core materials exhibit significant volume changes during the solid-liquid phase transition. If the coil is in direct contact, repeated expansion and contraction will generate mechanical stress, potentially leading to coil encapsulation cracking or electrical failure. Secondly, the liquid phase change core material may seep into the coil gaps, reducing insulation performance. In this invention, the support carrier provides the necessary structural strength for the heat storage layer, ensuring it can withstand vehicle loads before and after the phase transition, maintaining the overall stability of the wireless charging unit.

[0032] Preferably, the magnetic flux layer comprises non-magnetic concrete with a thickness of 60mm-100mm. For example, it can be made by using 1 part of (P.O42.5 grade) cement, 2.8-3.0 parts of limestone coarse aggregate, 1.7-1.8 parts of limestone fine aggregate, 0.45 parts of water, and 0.008-0.012 parts of polycarboxylate superplasticizer to form a magnetic flux layer with a relative magnetic permeability of 1.0-2.0 and a compressive strength ≥C40.

[0033] In some embodiments, the wireless charging prefabricated substrate is applied to the construction, renovation, and upgrading of wireless charging pavement structures for urban bus lanes. The magnetic bundle layer is 85mm thick, made of non-magnetic high-strength concrete with a relative magnetic permeability of 1.0-1.3 and a compressive strength ≥C40, and can be made of paramagnetic limestone aggregate.

[0034] In some embodiments, the prefabricated wireless charging substrate is used for the maintenance and upgrading of wireless charging pavement structures in highway service area parking spaces. The magnetic flux layer is 70mm thick, made of non-magnetic high-strength concrete, and has a relative magnetic permeability of 1.0-1.5.

[0035] In some embodiments, the wireless charging prefabricated substrate is applied in heavy-duty transportation channels within logistics parks, port terminals, and other similar environments. The magnetic layer is 110mm thick and is made of non-magnetic steel fiber reinforced high-strength concrete with a thermal conductivity (λ) of 1.7±0.2W / (m·K) and a relative magnetic permeability of 1.4±0.2.

[0036] Preferably, the thickness of the stress protection layer is 20mm-40mm, and high-viscoelastic polysulfide sealant or flexible epoxy resin mortar sealant can be used. For example, in some embodiments, the wireless charging prefabricated substrate is used in the construction, renovation, and upgrading of wireless charging pavement structures in urban bus lanes. The stress protection layer is 35mm thick, located at the bottom and sides of the wireless charging unit, and uses high-viscoelastic SBS and rubber composite modified asphalt mortar with an elastic modulus of 150±30MPa, elongation at break ≥220%, and coefficient of thermal expansion (22±4)×10. -6 / K.

[0037] In some embodiments, the wireless charging prefabricated substrate is used for the maintenance and upgrading of wireless charging pavement structures in parking spaces of highway service areas. The stress protection layer is 25mm thick, sealed with flexible epoxy resin mortar, has an elastic modulus of 350±50MPa, an elongation at break of over 160%, and a coefficient of thermal expansion of (18±3)×10⁻⁶. -6 / K.

[0038] In some embodiments, the wireless charging prefabricated substrate is applied in heavy-duty transportation channels within logistics parks, port terminals, and other similar environments. The stress protection layer is 40mm thick, sealed with flexible epoxy resin mortar, has an elastic modulus of 80±30MPa, an elongation at break greater than 280%, and a coefficient of thermal expansion of (25±5)×10⁻⁶. -6 / K.

[0039] Preferably, the wireless charging unit has a 20mm-40mm thick magnetic conductive layer at the top, a 25mm-35mm thick coil encapsulation thermal conductive layer in the middle, and a 30mm-60mm thick heat storage layer at the bottom. The heat storage layer is fabricated first, then the transmitting coil is placed on it and encapsulated, forming a coil encapsulation thermal conductive layer (including the transmitting coil) with a total encapsulation thickness of 25mm-35mm. A 20mm-40mm thick magnetic conductive layer is then laid on the cured coil encapsulation thermal conductive layer. These three layers are cured to form a single wireless charging unit, serving as the core template.

[0040] The magnetic conductive layer can be made of AC-13C dense-graded asphalt mixture with manganese-zinc ferrite particles (particle size 2-4mm), epoxy resin concrete with manganese-zinc ferrite particles, SMA-13 ​​mixture with ferrite particles, etc.

[0041] For example, in some embodiments, the prefabricated wireless charging matrix is ​​applied to the construction, renovation, and upgrading of wireless charging pavement structures for urban bus lanes. The magnetic conductive layer is 38mm thick, using AC-13C dense-graded asphalt mixture as the matrix, and incorporating 6% by mass of manganese-zinc ferrite particles (2-4mm in diameter) as the magnetic conductive functional phase. Preferably, 0.2% polyester fiber is added to improve crack resistance. The overall resistivity of the magnetic conductive layer is greater than 5×10³Ω·m, the relative permeability is 70±10, and the thermal conductivity is ≥1.3W / (m·K).

[0042] The coil encapsulation thermal conductive layer (including the transmitting coil) is 32mm thick. It is a large-size transmitting coil wound with multiple strands of Litz wire, with epoxy resin as the matrix and 40% by volume of alumina micron particles added. The thermal conductivity is 2.5±0.3W / (m·K).

[0043] The thermal storage layer is 45mm thick and uses shaped composite phase change plates. Paraffin wax (phase change temperature 54±1℃) is used as the phase change core material, high-density polyethylene as the supporting carrier, and 8% expanded graphite is added to improve thermal conductivity. The latent heat of phase change is ≥170kJ / kg. The single-layer dimensions of the shaped composite phase change plates are 500mm×500mm×45mm, and multiple layers are spliced ​​together to form the thermal storage layer.

[0044] In some embodiments, the prefabricated wireless charging substrate is used for the maintenance and upgrading of wireless charging pavement structures in highway service area parking spaces. The magnetic conductive layer is 28mm thick and is made of epoxy resin concrete incorporating 8% manganese-zinc ferrite particles. The overall resistivity of the magnetic conductive layer is greater than 8×10⁻⁶. 3 Ω·m, with a relative permeability of 90±10.

[0045] The coil encapsulation thermal conductive layer (including the transmitting coil) is 28mm thick. The double D-type Litz coil is the transmitting coil. The coil encapsulation thermal conductive layer is formed by encapsulating the double D-type Litz coil with modified polyurethane and has a thermal conductivity of 2.5W / (mK).

[0046] The heat storage layer is 55mm thick and uses a double-layer composite structure. The upper layer (approximately 38mm thick) is a high-strength cement substrate with embedded paraffin phase change capsules (phase change temperature of 60±2℃), and the lower layer (approximately 17mm thick) is a high specific heat capacity composite material formed by mixing a high thermal conductivity silicone rubber matrix with 40% alumina ceramic microspheres by volume. The two layers are bonded together using a hot-pressing process to form the heat storage layer.

[0047] In some embodiments, the wireless charging prefabricated substrate is applied in heavy-duty transportation channels within logistics parks, port terminals, and other similar environments. The magnetic conductive layer has a thickness of 42mm, using a high-strength, wear-resistant SMA-13 ​​composite as the matrix, and incorporating 4% by mass of ferrite particles (3-6mm in diameter) as the magnetic conductive functional phase. The overall resistivity of the magnetic conductive layer is greater than 10⁻⁶. 3 Ω·m, relative permeability 40±10; preferably, oil-resistant and aging-resistant modifiers are added to the asphalt to improve environmental tolerance.

[0048] The coil encapsulation thermal conductive layer (including the transmitting coil) is 38mm thick. The transmitting coil adopts a double D-type Litz coil. The encapsulation substrate is flexible epoxy resin, filled with 30% alumina and 10% chopped glass fiber by volume, with a thermal conductivity of 2.0±0.3W / (m·K).

[0049] The heat storage layer is 35mm thick and uses paraffin wax with a phase change temperature of 52±2℃ as the phase change core material. The paraffin wax phase change core material is sealed in a high-density polyethylene (HDPE) or thin-walled metal shell to form the heat storage layer.

[0050] In some embodiments, the concrete base can be made of cement concrete, polymer-modified concrete, or steel fiber reinforced concrete, preferably with a compressive strength ≥40MPa and a thickness of 30mm-50mm. For example, in some embodiments, the precast wireless charging base is used in the construction, renovation, and upgrading of wireless charging pavement structures for urban bus lanes. The concrete base is 45mm thick, made of C50 steel fiber reinforced concrete, with a compressive strength ≥60MPa, forming an overall protective structure against external loads and the environment.

[0051] In some embodiments, the prefabricated wireless charging substrate is used for the maintenance and upgrading of wireless charging pavement structures in highway service area parking spaces. The concrete base is 35mm thick, made of the same material as the magnetic conductive layer, and forms a "U" shaped groove.

[0052] In some embodiments, the prefabricated wireless charging substrate is used in applications such as logistics parks and port terminals with heavy-duty transportation channels. The concrete base is 45mm thick, made of the same material as the magnetic conductive layer, and the aggregate can be made of wear-resistant basalt, forming a "U" shaped groove.

[0053] A method for preparing a wireless charging preform as described in this invention includes the following steps: (1) Preparation of concrete base: pour cement slurry into the mold according to the preset size, and reserve the power connection hole to form a U-shaped groove with the opening facing upward, which is the concrete base.

[0054] (2) Preparation of wireless charging unit: First, make a heat storage layer, then place the transmitting coil on the heat storage layer, and use insulating material to encapsulate and solidify the transmitting coil to form a coil encapsulation heat conduction layer; lay a magnetic conductive layer of a preset thickness on the solidified coil encapsulation heat conduction layer, and solidify these three layers to form an integral wireless charging unit.

[0055] (3) Applying a stress protection layer: Apply stress protection layer material evenly to the bottom and surrounding sides of the obtained wireless charging unit to form a stress protection layer.

[0056] (4) Integral molding: After the stress protection layer is dry, place it in the center of the "U" shaped groove made in step (1), pour non-magnetic material into the gap between the stress buffer layer and the concrete base installation groove to form a magnetic bead layer, which is used to constrain the magnetic field, so that the electromagnetic energy is transmitted upward in a directional manner, reducing lateral magnetic leakage, curing and molding, and obtaining the wireless charging prefabricated substrate.

[0057] In some embodiments, the design dimensions of the wireless charging prefabricated substrate are 1000mm (length) × 2000mm (width) × 220mm (thickness); Step (2) prepares the wireless charging unit, as follows: Using a thermal storage material with a phase change temperature of 50℃-70℃ and a latent heat of phase change ≥150kJ / kg, a thermal storage layer with a thickness of 30mm-60mm is first fabricated. Then, a transmitting coil is placed on the thermal storage layer, and the transmitting coil is encapsulated and cured with insulating material to form a coil encapsulation thermally conductive layer with a total encapsulation thickness of 25mm-35mm (including the transmitting coil). A magnetically conductive layer with a thickness of 20mm-40mm is then laid on the cured coil encapsulation thermally conductive layer. These three layers are cured to form a single wireless charging unit, serving as the core template.

[0058] The following are examples. Example 1: Wireless charging pavement structure applicable to urban bus lanes This embodiment employs a prefabricated charging pavement structure, requiring only grooving and joint treatment on-site. It is suitable for the construction, renovation, and upgrading of wireless charging pavement structures for urban bus lanes. Buses operate frequently, with daily running hours exceeding 16 hours, subjecting the pavement structure to repeated impacts from high-frequency, heavy loads. Simultaneously, the urban heat island effect can lead to high pavement temperatures in summer. Therefore, the core design features of this embodiment are superior long-term mechanical durability, efficient and continuous heat dissipation, and stable and reliable power transmission performance to address the dual challenges of heavy traffic loads and heat accumulation.

[0059] 1. Structural and material design of precast blocks The precast block dimensions are designed to be 1000mm (length) × 2000mm (width) × 220mm (thickness), and the complete internal structure of a single block is as follows: Figure 1As shown, from the outside in, the structure includes a concrete base with a pre-sized mounting slot, a magnetic flux layer, a stress protection layer, and a wireless charging unit. The wireless charging unit, as the core module, includes a magnetic conductive layer (top), a coil encapsulation heat-conducting layer (middle), and a heat storage layer (bottom). The specific structures of each functional layer are as follows: a) Magnetic Conductive Layer (Top): 38mm thick, using AC-13C dense-graded asphalt mixture as the matrix (for road traffic, using anti-skid and wear-resistant asphalt mixture). Raw materials, by weight, include 5 parts asphalt, 55 parts coarse aggregate, 20 parts fine aggregate, 5 parts mineral powder, 8 parts manganese-zinc ferrite particles (2-4mm particle size) produced by Shandong Chunguang Technology Group, and 0.15 parts dispersant. The coarse and fine aggregates are dried and preheated to 170℃; the manganese-zinc ferrite particles and dispersant (stearic acid or polyethylene wax) are premixed and added to a mixer, dry-mixed for 15 seconds; asphalt at 150~160℃ is added and wet-mixed for 90~120 seconds, then the mineral powder is added and mixed until uniform. The mixing temperature is 170~175℃ to obtain the magnetic conductive layer asphalt mixture. The resistivity of the prepared magnetic conductive layer is greater than 5×10³Ω·m, the relative magnetic permeability is 70±10, and the thermal conductivity is ≥1.3W / (m·K).

[0060] b) Coil Encapsulation Thermal Conductive Layer (Middle): 32mm thick, using a large-size transmitting coil of 600mm×1600mm wound with multi-strand Litz wire, with epoxy resin as the matrix and 40% by volume alumina micron particles added.

[0061] c) Thermal storage layer (bottom): 45mm thick, using shaped composite phase change plates. The shaped composite phase change plates mainly consist of two parts: a phase change core material and a support and encapsulation skeleton (support carrier). In this embodiment, 56# fully refined paraffin wax produced by China National Petroleum Corporation (CNPC) is used as the phase change core material, and HHM5502LW high-density polyethylene produced by China Petroleum & Chemical Corporation (Sinopec) is used as the support carrier. 8% graphite (fixed carbon content ≥95%) produced by Qingdao Baixing Graphite Co., Ltd. is added to improve thermal conductivity. The paraffin wax has a phase change temperature of 54±1℃ and a latent heat of phase change ≥170kJ / kg. The plates are prefabricated to 500mm×500mm×45mm specifications, and multiple layers are spliced ​​together to form a whole.

[0062] d) Stress protection layer: 35mm thick, located at the bottom and sides of the core module, using high viscoelastic SBS and rubber composite modified asphalt mortar, with an elastic modulus of 150±30MPa, elongation at break ≥220%, and coefficient of thermal expansion (22±4)×10⁻ 6 / K.

[0063] e) Magnetic bead layer: 85mm thick, a stress protection layer that wraps around the side of the core module, made of 1 part (P.O42.5 grade) cement; 2.8-3.0 parts coarse limestone aggregate; 1.7-1.8 parts fine limestone aggregate; 0.45 parts water; and 0.01 parts polycarboxylate superplasticizer, to form a magnetic bead layer with a relative magnetic permeability of 1.0-1.3 and a compressive strength ≥ C40.

[0064] f) Concrete base: C50 steel fiber reinforced concrete, 45mm thick, forming an upward-opening "U" shaped groove, with pre-reserved power connection holes, located at the bottom layer and outer wall of the precast block. Its raw materials, by weight, include: 1.0 part cement, 2.5 parts basalt coarse aggregate, 1.55 parts river sand, 0.18 parts steel fiber, 0.37 parts water, and 0.015 parts water-reducing agent. High-precision steel molds are used, with release agent applied to the inner wall. First, dry mix cement, coarse aggregate, and fine aggregate for 30 seconds, add steel fiber and continue dry mixing for 30 seconds, then add water and water-reducing agent and wet mix for 90 seconds to obtain the steel fiber reinforced concrete mixture. First, pour the bottom concrete and vibrate to compact it; then pour the concrete for the surrounding side walls, vibrating in layers. Before pouring the side walls, pre-embed conduits and reserve power connection holes. After pouring, cover with a damp cloth for 24 hours of curing, and continue curing for 7 days after demolding. After the curing period, the 28-day compressive strength of the concrete base is ≥60MPa and the flexural strength is ≥8MPa, forming an overall protective structure against external loads and environmental erosion.

[0065] 2. Factory prefabrication process a) Mold preparation and concrete base pouring: Using high-precision steel molds, first pour concrete base material (1.0 part cement, 2.5 parts basalt coarse aggregate, 1.55 parts river sand, 0.18 parts steel fiber, 0.37 parts water, 0.015 parts water-reducing agent) at the bottom and around the mold, vibrate to compact, form an upward-opening "U" shaped groove, and reserve power connection holes.

[0066] b) Module Assembly: First, fabricate the heat storage layer material. Place the transmitting coil above the center of the heat storage layer. Using epoxy resin as the matrix, add 40% by volume of alumina micronized particles and stir evenly to obtain an encapsulation material. Then, inject the encapsulation material into the mold, ensuring it completely submerges the transmitting coil and fills the cavity. After curing at room temperature for 2 hours, obtain the coil encapsulation thermal conductive layer. Spray high-viscosity epoxy resin onto the cured encapsulation layer, spread a magnetic asphalt mixture, and vibrate and compact it to form a magnetic layer. Cure these three layers into a single wireless charging unit, serving as the core module.

[0067] c) Stress layer coating: Apply a highly viscoelastic SBS and rubber composite modified asphalt mortar evenly to the bottom and around the "core module" to form a stress protection layer.

[0068] d) Integral molding: After the stress layer has dried to the surface, place the core module in the center of the "U"-shaped groove made in step 1, and pour non-magnetic material into the gap between them to form a magnetic bead layer. The non-magnetic material is non-magnetic high-strength concrete, including 1 part of cement (P.O42.5 grade); 2.8-3.0 parts of limestone coarse aggregate; 1.7-1.8 parts of limestone fine aggregate; 0.45 parts of water; and 0.01 parts of water-reducing agent.

[0069] e) Curing and Delivery: The precast blocks are steam-cured for 24 hours and then naturally cured for 28 days. Before delivery, an electrical test is performed to ensure that the inductance deviation of the transmitting coil is <5% and the insulation resistance is >100MΩ.

[0070] 3. On-site construction and installation process The on-site construction adopts a rapid operation method of "milling-hoisting-grouting", which is suitable for the simultaneous construction of existing road surface renovation or new road construction for urban bus lanes. a) Road surface trenching and base layer treatment: On existing road surfaces or newly constructed base courses, accurately lay out the precast block dimensions. Use a heavy-duty milling machine or cutter to excavate an installation groove with a depth of 240mm (leaving a 20mm leveling layer). The bottom and sidewalls of the groove should be flat and firm.

[0071] The bottom of the trench is purged and moistened under high pressure. A 20mm thick layer of high-strength polymer mortar is laid for leveling (28-day compressive strength ≥50MPa), and the main power supply line and grounding system are pre-embedded. The surface of the leveling layer is roughened to enhance the adhesion to the precast blocks.

[0072] b) Precast block hoisting and wiring: After the leveling layer reaches 70% strength (approximately 24-48 hours), the precast blocks are hoisted into the installation slot. Precision leveling is performed using the leveling supports at the bottom of the precast blocks to ensure that the top surface elevation of the precast blocks matches the designed road surface elevation, with a height difference of ≤2mm between adjacent modules. The coil lead wires and main power lines are connected through pre-drilled holes, with IP68-rated waterproof connectors used at the interfaces and insulated with insulating glue to ensure reliable and waterproof electrical connections.

[0073] c) Joint treatment and pavement restoration: Inter-module gaps: The gaps between adjacent precast blocks (approximately 10-15mm wide) are filled with highly elastic, weather-resistant polyurethane sealant. This material has an elongation at break of ≥200% and can accommodate the differential deformation between modules.

[0074] Gaps between modules and surrounding road surfaces: The gaps between the precast blocks and the existing road surface (approximately 15-20mm wide) are first filled with elastic polyurethane rubber mortar up to 30mm from the surface, and then a wear-resistant asphalt concrete is poured in for surface sealing, flush with the surrounding road surface, to ensure smooth driving and prevent rainwater from seeping in.

[0075] d) System debugging and opening of traffic: After all joints have cured for 24 hours, the entire system will be powered on and tested to assess wireless charging efficiency, communication stability, and magnetic leakage levels. Once the road surface has naturally cooled to room temperature and all indicators meet design requirements, the road can be opened to traffic. For heavy-load areas of the bus lane, a 48-hour static curing period can be implemented before opening to traffic to ensure all bonding materials reach their design strength.

[0076] Example 2: Wireless charging pavement structure applicable to parking spaces in highway service areas This embodiment employs a factory-prefabricated charging pavement structure, requiring only grooving and joint treatment on-site. It is suitable for the maintenance and upgrading of wireless charging pavement structures in highway service area parking spaces. Its main characteristics are high peak-time, short-duration, concentrated heat generation, and a long heat dissipation interval after charging. Therefore, the core design of this embodiment lies in high magnetic circuit efficiency, rapid conduction and buffering of peak heat flow, and excellent thermal cycling durability. 1. Structural and Material Design of Prefabricated Blocks The precast block dimensions are designed to be 1000mm (length) × 2000mm (width) × 200mm (thickness), and the complete internal structure of a single block is as follows: Figure 1 As shown, the system includes, from the outside in, a concrete base with a pre-sized mounting groove, a magnetic flux layer, a stress protection layer, and a wireless charging unit. The wireless charging unit, as the core module, includes a magnetic conductive layer (top), a coil encapsulation heat-conducting layer (middle), and a heat storage layer (bottom). The specific structures of each functional layer are as follows: a) Magnetic conductive layer (top): 28mm thick, made of concrete incorporating manganese-zinc ferrite particles. The raw materials, by weight, include: 5 parts cement; 1-3 parts manganese-zinc ferrite particles; 2-4 parts fine aggregate; 3.5-5.5 parts water; 0.1-0.2 parts water-reducing agent; preferably: 10 parts cement, 2.0 parts manganese-zinc ferrite particles, 15 parts fine aggregate, 4.5 parts water, and 0.1 parts water-reducing agent.

[0077] Weigh the cement, manganese-zinc ferrite particles, and fine aggregate according to the specified mass ratios and add them to a mixer. Dry mix for 1 minute until uniform. Then add water and water-reducing agent and continue wet mixing for 2-3 minutes until a uniform slurry is formed. Pour the slurry into a mold, controlling the thickness according to design requirements. Compact the slurry using a vibrating table or immersion vibrator. Smooth the surface and cover with a damp cloth. Cure for 28 days under standard curing conditions to obtain a magnetically conductive layer with an overall resistivity greater than 8 × 10⁻⁶. 3 Ω·m, with a relative permeability of 90±10.

[0078] b) Coil Encapsulation Thermal Conductive Layer (including transmitting coil) (middle): 28mm thick, made of multi-strand Litz wire wound into a double D-type Litz coil, with modified polyurethane (thermal conductivity of 2.5W / (mK)) as the base material, and the double D-type Litz coil is encapsulated with modified polyurethane with thermal conductivity of 2.5W / (mK).

[0079] c) Thermal storage layer (bottom): 55mm thick, using a double-layer composite structure. The upper layer (approximately 38mm thick) is a high-strength cement substrate with embedded paraffin phase change capsules, and the lower layer (approximately 17mm thick) is a high-specific-heat-capacity composite material formed by mixing a high thermal conductivity silicone rubber matrix with 40% alumina ceramic microspheres by volume. The two layers are bonded together into a single sheet using a hot-pressing process. The phase change temperature is set at 60±2℃.

[0080] d) Stress protection layer: 25mm thick, located at the bottom and sides of the core module, sealed with flexible epoxy resin mortar, with an elastic modulus of 350±50MPa, elongation at break higher than 160%, and coefficient of thermal expansion: (18±3)×10⁻ 6 / K.

[0081] e) Magnetic Beam Layer: 70mm thick, a stress protection layer wrapping the sides of the core module, made of non-magnetic high-strength concrete, including 1 part (P.O42.5 grade) cement; 2.8 parts limestone coarse aggregate; 1.7 parts limestone fine aggregate; 0.45 parts water; and 0.008 parts polycarboxylate superplasticizer, forming a magnetic beam layer with a relative magnetic permeability of 1.0-1.2.

[0082] f) Concrete base: 35mm thick, located at the bottom layer and outer wall of the precast block, made of the same material as the magnetic conductive layer, forming a "U" shaped groove, and with reserved power wiring holes.

[0083] 2. Factory Prefabrication Process: Prefabricated blocks are produced in a factory under constant temperature and humidity conditions according to the following steps: a) Mold preparation and concrete base pouring: Using high-precision steel molds, first pour concrete base material at the bottom and around the mold, vibrate and compact it to form an upward-opening "U" shaped groove, and reserve power connection holes.

[0084] b) Module Assembly: First, fabricate the heat storage layer material. Place the transmitting coil above the center of the heat storage layer. Using modified polyurethane (thermal conductivity 2.5 W / (mK)) as the matrix, stir evenly to obtain an encapsulation material. Then, inject the encapsulation material into the mold, ensuring it completely submerges the transmitting coil and fills the cavity. After curing at room temperature for 2 hours, a coil encapsulation thermal conductive layer is obtained. High viscoelastic epoxy resin is sprayed onto the cured encapsulation layer, and a magnetic asphalt mixture is spread and vibrated to compact it, forming a magnetic layer. These three layers are then cured into a single wireless charging unit, serving as the core module.

[0085] c) Stress layer coating: Apply flexible epoxy resin mortar sealant evenly to the bottom and around the "core module" to form a stress protection layer.

[0086] d) Integral molding: After the stress layer has dried to the surface, place the core module in the center of the "U"-shaped groove made in step 1, and pour non-magnetic material into the gap between them to form a magnetically conductive layer. The non-magnetic material is non-magnetic high-strength concrete, including 1 part of low-magnetic cement (P.O42.5 grade); 2.8 parts of limestone coarse aggregate; 1.7 parts of limestone fine aggregate; 0.45 parts of water; and 0.008 parts of polycarboxylate superplasticizer.

[0087] e) Curing and Delivery: The precast blocks are steam-cured for 24 hours and then naturally cured for 28 days. Before delivery, an electrical test is performed to ensure that the inductance deviation of the transmitting coil is <5% and the insulation resistance is >100MΩ.

[0088] 3. On-site construction and installation process: On-site construction adopts a rapid operation method of "milling-hoisting-grouting": a) Road grooving and base treatment: On the existing road surface (or the base of a newly built road surface), mill or formwork is used according to the size of the precast blocks to excavate an installation groove with a depth of 210mm (with a 10mm leveling layer reserved). A 10mm thick quick-drying cement mortar leveling layer is laid at the bottom of the groove, and the main power supply line is pre-embedded.

[0089] b) Precast block hoisting and wiring: After the leveling layer reaches 70% strength, use a truck-mounted crane to hoist the precast blocks into the installation slot. Connect the coil lead wire and the main power line through the reserved holes, using an IP68 waterproof connector at the interface and filling it with insulating glue.

[0090] c) Joint treatment and magnetic circuit closure: The gap between the precast block and the surrounding road surface (approximately 10-15mm wide) is filled with high-viscoelastic modified asphalt mastic to coordinate the deformation of the old and new road surfaces and prevent rainwater from seeping in.

[0091] Example 3 is applicable to wireless charging pavement structures for internal heavy-duty transport channels in logistics parks, port terminals, etc. This embodiment employs a factory-prefabricated charging pavement structure, requiring only on-site grooving and joint treatment. It is optimized for applications in logistics parks, port terminals, and other internal heavy-duty transportation corridors. Its main characteristics are relatively low usage frequency but extreme loads, environments potentially containing corrosive media such as oil and de-icing agents, and significant temperature variations. Therefore, the core design focus of this embodiment is high mechanical load-bearing capacity and impact resistance, excellent environmental tolerance, and long-term structural integrity under harsh conditions, while also ensuring maintainability.

[0092] The precast block dimensions are designed to be 1000mm (length) × 2000mm (width) × 200mm (thickness), and the complete internal structure of a single block is as follows: Figure 1 As shown, it specifically includes the following functional layer structure: a) Magnetic Conductive Layer (Top): 42mm thick. Raw materials, by weight, include 6 parts asphalt, 70 parts coarse aggregate, 35 parts fine aggregate, 5 parts mineral powder, 6 parts manganese-zinc ferrite particles (produced by Shandong Chunguang Technology Group), and 0.3 parts dispersant. The coarse and fine aggregates are dried and preheated to 170℃. The manganese-zinc ferrite particles and dispersant (stearic acid or polyethylene wax) are premixed and added to a mixer, dry-mixed for 15 seconds. The asphalt is then wet-mixed at 160℃ for 120 seconds, followed by the addition of mineral powder and mixing until homogeneous. The mixing temperature remains at 170℃ to obtain the magnetic conductive layer asphalt mixture. The overall resistivity of the magnetic conductive layer is greater than 10 Ω·cm. 3 Ω·m, with a relative permeability of 40±10.

[0093] b) Coil Encapsulation Thermal Conductive Layer (including transmitting coil) (middle): 38mm thick, using a double D-type Litz coil, with epoxy resin as the matrix, and incorporating 30% by volume alumina and 10% by volume short glass fiber. The thermal conductivity of the coil encapsulation thermal conductive layer is 2.0±0.3W / (m·K).

[0094] c) Heat storage layer (bottom): 35mm thick, the paraffin phase change core material is sealed in high-density polyethylene (HDPE), the paraffin phase change temperature is 52±2℃.

[0095] d) Stress protection layer: 40mm thick, located at the bottom and sides of the core module, sealed with flexible epoxy resin mortar, with an elastic modulus of 80±30MPa, elongation at break higher than 280%, and coefficient of thermal expansion of (25±5)×10⁻ 6 / K.

[0096] e) Magnetic Beam Layer: 110mm thick, a stress protection layer encasing the sides of the core module. It is made of 1 part (P.O42.5 grade) cement; 3.0 parts coarse limestone aggregate; 1.7-1.8 parts fine limestone aggregate; 0.45 parts water; and 0.01 parts polycarboxylate superplasticizer, resulting in a magnetic beam layer with a relative permeability of 1.0-1.3 and a compressive strength ≥ C40. The thermal conductivity (λ) of the magnetic beam layer is 1.7±0.2 W / (m·K), and the relative permeability is 1.4±0.2.

[0097] f) Concrete base: 45mm thick, located at the bottom layer and outer wall of the precast block, made of the same material as the magnetic conductive layer, with wear-resistant basalt as aggregate, forming a "U" shaped groove, and with reserved power wiring holes.

[0098] 2. Factory Prefabrication Process: Prefabricated blocks are produced in a factory under constant temperature and humidity conditions according to the following steps: a) Mold preparation and concrete base pouring: Using high-precision steel molds, first pour concrete base material at the bottom and around the mold, vibrate and compact it to form an upward-opening "U" shaped groove, and reserve power connection holes.

[0099] b) Module Assembly: First, fabricate the heat storage layer material. Place the transmitting coil above the center of the heat storage layer. Using epoxy resin as the matrix, add 30% by volume of alumina micronized particles and 10% by volume of chopped glass fibers, and stir evenly to obtain an encapsulation material. Then, inject the encapsulation material into the mold, ensuring it completely submerges the transmitting coil and fills the cavity. After curing at room temperature for 2 hours, obtain the coil encapsulation heat-conducting layer. Spray high-viscosity epoxy resin onto the cured encapsulation layer, spread a magnetic asphalt mixture, and vibrate and compact it to form a magnetic layer. Cure these three layers into a single wireless charging unit, serving as the core module.

[0100] c) Stress layer coating: Apply stress protection layer material (flexible epoxy resin mortar sealant) evenly to the bottom and around the "core module".

[0101] d) Integral molding: After the stress layer has dried to the surface, place the core module in the center of the "U"-shaped groove made in step 1, and pour non-magnetic material into the gap between them to form a magnetic bead layer. The non-magnetic material is non-magnetic high-strength concrete, including 1 part of cement (P.O42.5 grade); 3.0 parts of limestone coarse aggregate; 1.7-1.8 parts of limestone fine aggregate; 0.45 parts of water; and 0.01 parts of polycarboxylate superplasticizer.

[0102] e) Curing and Delivery: The precast blocks are steam-cured for 24 hours and then naturally cured for 28 days. Before delivery, an electrical test is performed to ensure that the coil inductance deviation is <5% and the insulation resistance is >100MΩ.

[0103] 3. On-site construction and installation process: On-site construction adopts a rapid operation method of "milling-hoisting-grouting": a) Road grooving and base treatment: On the existing road surface (or the base of a newly built road surface), mill or formwork is used according to the size of the precast blocks to excavate an installation groove with a depth of 210mm (with a 10mm leveling layer reserved). A 10mm thick quick-drying cement mortar leveling layer is laid at the bottom of the groove, and the main power supply line is pre-embedded.

[0104] b) Precast block hoisting and wiring: After the leveling layer reaches 70% strength, use a truck-mounted crane to hoist the precast blocks into the installation slot. Connect the coil lead wire and the main power line through the reserved holes, using an IP68 waterproof connector at the interface and filling it with insulating glue.

[0105] c) Joint treatment and magnetic circuit closure: The gap between the precast block and the surrounding road surface (approximately 10-15mm wide) is filled with high-viscoelastic modified asphalt mastic to coordinate the deformation of the old and new road surfaces and prevent rainwater from seeping in.

[0106] Comparative Example 1 The difference between this comparative example and Example 1 is that the wireless charging prefabricated substrate structure does not include a magnetic flux layer; that is, the sides and bottom of the core functional module are not wrapped with low-permeability material and are in direct contact with the stress protection layer. The specific preparation steps are the same as in Example 1.

[0107] Comparative Example 2 The difference between this comparative example and Example 2 is that the wireless charging prefabricated substrate structure does not include a stress protection layer; that is, the bottom and sides of the core functional module are in direct rigid contact with the inner wall of the magnetic flux layer. The specific preparation steps are the same as in Example 1.

[0108] Comparative Example 3 The difference between this comparative example and Example 3 is that the wireless charging prefabricated substrate structure does not include a heat storage layer; that is, the coil encapsulation heat-conducting layer is in direct contact with the stress protection layer at the bottom of the magnetic flux layer and the concrete base. The specific preparation steps are the same as in Example 1.

[0109] The performance of the wireless charging prefabricated substrates of Examples 1-3 and Comparative Examples 1-3 were compared, and the results are shown in the table below.

[0110] Table 1 Comparison of Electromagnetic Properties A comparison between Example 1 and Comparative Example 1 shows that the charging efficiency of Comparative Example 1 (without a magnetic confinement layer) at 20cm is only 75%, which is about 17% lower than that of Example 1. The roadside magnetic leakage at 1m in Comparative Example 1 is as high as 28μT, which is 6μT higher than that in Example 1, indicating a significant risk of electromagnetic leakage. The increased coil losses due to magnetic field divergence demonstrate that the magnetic confinement layer in this wireless charging prefabricated substrate structure can effectively confine the magnetic field, improve transmission efficiency, and reduce the risk of magnetic leakage.

[0111] This invention, designed for the extreme heavy-load and corrosive environments of logistics parks, prioritizes mechanical strength and corrosion resistance. The magnetic conductive layer utilizes a low-dosage manganese-zinc ferrite powder, along with a higher proportion of coarse and fine aggregates to enhance its mechanical properties. These aggregates have low magnetic permeability, and the stress protection layer is thickened to 40mm. Although its coupling coefficient and transmission efficiency are lower compared to other road surfaces (such as urban bus lanes and highway service area parking spaces), logistics parks and port container trucks often have long parking times (several hours), providing ample time for wireless charging.

[0112] Table 2 Comparison of Thermal Management Performance Table 3 Mechanical and Durability Properties As demonstrated in Examples 1-3, the directional magnetic transmission wireless charging prefabricated substrate of the present invention exhibits excellent comprehensive performance in different application scenarios: the static charging efficiency at a 20cm spacing reaches 87%~94%, the leakage magnetic field at 1m on the roadside is controlled at 13~22μT, meeting the electromagnetic safety limits of GB / T38775.4-2020; the coil temperature rise at rated power is 33~39℃, and the highest surface temperature of the road surface is 51~58℃, showing a significant synergistic effect of heat dissipation and heat storage; the interlayer shear strength reaches 1.21~1.28MPa, and the fatigue life at 0.5 stress ratio exceeds 34,000 cycles, demonstrating excellent durability.

[0113] A comparison of Examples 1, 2, and 3 shows that by adjusting key parameters such as the thickness of the magnetic conductive layer (28~42mm) and its permeability (40~90), the thickness of the heat storage layer (35~55mm) and its phase transition temperature (52~60℃), the modulus of the stress protection layer (80~350MPa), and the thickness of the magnetic flux layer (70~110mm) for different application scenarios, the resulting wireless charging prefabricated substrate can be adapted to the differentiated needs of urban bus lanes (heavy load, high frequency), highway service areas (peak hours, short-term high heat), and logistics parks (extreme heavy load, corrosion).

[0114] Data from Tables 1 to 3 show that: in the public transportation scenario, the charging efficiency reaches 92% and the fatigue life is 35,247 cycles; in the service area scenario, the charging efficiency is improved to 94% and the coil temperature rises to 33℃; in the logistics park scenario, the interlayer shear strength reaches 1.28 MPa and the fatigue life is 36,289 cycles. These results demonstrate that, through reasonable layer thickness and material parameter design, the wireless charging prefabricated substrate structure provided by this invention combines charging efficiency, thermal management, and mechanical durability, effectively extending the service life of the wireless charging system and providing a reliable technical solution for the engineering application of wireless charging infrastructure.

[0115] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wireless charging prefabricated substrate based on directional magnetic transmission, employing electromagnetic induction charging, characterized in that, From the outside in, it includes a concrete base with a pre-sized mounting groove, a magnetic bead layer, a stress protection layer, and a wireless charging unit; the wireless charging unit is set in the mounting groove of the concrete base, the stress protection layer is uniformly coated on the bottom and surrounding sides of the wireless charging unit, and a non-magnetic material is poured into the gap between the stress protection layer and the mounting groove of the concrete base to form a magnetic bead layer, which is used to constrain the magnetic field, so that the electromagnetic energy is transmitted upward in a directional manner and the lateral magnetic leakage is reduced; The relative permeability of the magnetic flux layer is ≤2.0; the elastic modulus of the stress protection layer is 50MPa~500MPa; The wireless charging unit comprises, from top to bottom, a magnetic conductive layer, a coil encapsulation heat-conducting layer, and a heat storage layer; the magnetic conductive layer has a relative permeability of more than 50 times that of the magnetic coil layer; the coil encapsulation heat-conducting layer is formed by encapsulating the transmitting coil with insulating material; the heat storage layer includes a phase change core material and a supporting carrier.

2. The wireless charging prefabricated substrate as described in claim 1, characterized in that, The magnetic bead layer is made of non-magnetic concrete with a thickness of 60mm-100mm; the stress protection layer has a thickness of 20mm-40mm and is made of high viscoelastic polysulfide sealant or flexible epoxy resin mortar sealant.

3. The wireless charging prefabricated substrate as described in claim 2, characterized in that, The wireless charging prefabricated substrate is used in the construction, renovation and upgrading of wireless charging pavement structure for urban bus lanes. The magnetic bundle layer has a thickness of 70mm-95mm, a relative magnetic permeability of 1.0-2.0, and a compressive strength ≥C40. Preferably, the stress protection layer has a thickness of 30mm-40mm and is made of a high-viscosity SBS and rubber composite modified asphalt mortar with an elastic modulus of 150±30MPa, an elongation at break ≥220%, and a coefficient of thermal expansion of (22±4)×10. -6 / K.

4. The wireless charging prefabricated substrate as described in claim 2, characterized in that, The wireless charging prefabricated substrate is used for the maintenance and upgrading of wireless charging pavement structures in parking spaces of highway service areas. The magnetic bundle layer has a thickness of 60mm-80mm and a relative magnetic permeability of 1.0-1.

5. Preferably, the stress protection layer has a thickness of 20-35mm, is sealed with flexible epoxy resin mortar, has an elastic modulus of 350±50MPa, an elongation at break ≥160%, and a coefficient of thermal expansion of (18±3)×10. -6 / K.

5. The wireless charging prefabricated substrate as described in claim 2, characterized in that, The wireless charging prefabricated substrate is used in heavy-duty transportation channels inside logistics parks, ports and docks, etc. The magnetic layer has a thickness of 100-130mm and a relative magnetic permeability of 1.4±0.

2. Preferably, the stress protection layer has a thickness of 35-45mm, is sealed with flexible epoxy resin mortar, has an elastic modulus of 80±30MPa, an elongation at break of ≥280%, and a coefficient of thermal expansion of (25±5)×10. -6 / K.

6. The wireless charging prefabricated substrate as described in any one of claims 1 to 5, characterized in that, The wireless charging unit has a magnetic conductive layer with a thickness of 20mm-40mm at the top, a coil encapsulation heat-conducting layer with a thickness of 25mm-35mm in the middle, and a heat storage layer with a thickness of 30mm-60mm at the bottom. The heat storage layer is formed by filling a phase change core material into a support carrier. The phase change core material includes paraffin wax with a phase change temperature of 50℃-70℃ and a latent heat of phase change of ≥150kJ / kg. The support carrier includes one or more of high-density polyethylene, cement substrate, and silicone rubber matrix.

7. The wireless charging prefabricated substrate as described in claim 6, characterized in that, The relative magnetic permeability of the magnetic conductive layer is 50-100 times that of the magnetic bundle layer, including AC-13C dense-graded asphalt mixture with manganese-zinc ferrite particles, epoxy resin concrete with manganese-zinc ferrite particles, or SMA-13 ​​mixture with ferrite particles.

8. A method for preparing a wireless charging prefabricated substrate as described in any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Prepare concrete base: pour concrete material according to the mold of the preset size, and reserve power wiring hole to form an upward-opening "U" shaped groove to obtain concrete base; (2) Preparation of wireless charging unit: fill phase change core material into support carrier to form heat storage layer, place transmitting coil on heat storage layer, encapsulate and solidify transmitting coil with insulating material to form coil encapsulation heat conduction layer; lay magnetic conductive layer of preset thickness on coil encapsulation heat conduction layer, and solidify these three layers to form an integral wireless charging unit. (3) Applying a stress protection layer: Apply stress protection layer material evenly to the bottom and surrounding sides of the obtained wireless charging unit; the stress protection layer material includes high viscoelastic polysulfide sealant or flexible epoxy resin mortar sealant. (4) Integral molding: After the stress protection layer is dry, it is placed in the center of the "U" shaped groove made in step (1), and non-magnetic material is poured in the gap between the two to form a magnetic layer. After curing, the wireless charging prefabricated substrate is obtained; the non-magnetic material includes concrete material with a relative magnetic permeability ≤2.

0.

9. The preparation method according to claim 8, characterized in that, The phase change core material in step (2) includes paraffin wax with a phase change temperature of 50℃-70℃ and a latent heat of phase change of ≥150kJ / kg; the support carrier includes one or more of high-density polyethylene, cement substrate, and silicone rubber matrix.

10. The preparation method according to claim 9, characterized in that, The magnetic conductive layer is made of AC-13C dense-graded asphalt mixture with manganese-zinc ferrite particles, concrete with manganese-zinc ferrite particles, or SMA-13 ​​mixture with ferrite particles.

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