Power electronic equipment placing box and manufacturing process thereof

Abstract

The invention relates to a power electronic equipment placement box and a manufacturing process thereof. The power electronic equipment placing box comprises a box body and an RFID automatic identification system used for scanning and identifying power electronic equipment. The box body is made of a light-weight shielding plate, the light-weight shielding plate comprises a primary outer layer, a compression-resistant filling layer, a primary shielding layer, a secondary outer layer, a main shielding layer and a buffer layer which are sequentially arranged, and the primary outer layer and the secondary outer layer each comprise a plurality of carbon fiber layers which are arranged in a stacked mode and arranged in a crossed mode in the longitude and latitude directions; the RFID automatic identification system comprises a reader-writer and a vertical polarization planar antenna, and the vertical polarization planar antenna is arranged in the center of the inner wall of the top plate of the box body. The light-weight design is adopted, carrying is convenient, and the labor cost can be saved; the impact resistance is excellent; good electromagnetic shielding performance is achieved, and the equipment stability is guaranteed; aging, corrosion or deformation cannot easily occur; and meanwhile, an intelligent identification function is integrated.

Description

Technical Field

[0001] This invention relates to the field of intelligent transportation and warehousing management technology for power electronic equipment, and in particular to a lightweight, intelligent RFID power electronic equipment placement box with electromagnetic shielding function and its manufacturing process. Background Technology

[0002] With the development of intelligent power systems, an increasing number of sophisticated electronic devices need to be frequently moved between substations, dispatch centers, and maintenance bases. The transport containers used in this process are mostly made of aluminum alloy frames and aerospace-grade wooden crates or fiberglass reinforced plastic (FRP) boxes, which have the following drawbacks: 1. Heavy weight: The overall weight reaches 18-25kg, making it difficult to move and increasing labor costs; 2. Limited impact resistance: The internal cushioning material is mostly PU foam, which has low compressive strength (<0.2MPa) and is difficult to withstand drops or vibrations; 3. No electromagnetic shielding design: It cannot block external EMI interference, nor can it prevent internal signal leakage, affecting the stability of the equipment. Especially when using UHF RFID (920–925 MHz) for automatic equipment identification, traditional unshielded enclosures have serious signal leakage problems—antenna radiation penetrates the enclosure wall, misreading items in the vicinity and causing inventory errors; at the same time, due to the lack of a reflection mechanism, there are a lot of signal dead zones inside the enclosure, causing missed readings. 4. Lack of intelligent identification function integration: It cannot support RFID automatic inventory, and relying on manual counting is inefficient and prone to errors; 5. Poor environmental adaptability: It is prone to aging, corrosion or deformation in high temperature and humid environments. Summary of the Invention

[0003] The purpose of this invention is to provide a power electronic equipment placement box that solves the above-mentioned technical problems, has the advantages of being lightweight, having strong impact resistance, good electromagnetic shielding function, good environmental adaptability, and integrating intelligent identification function.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A power electronic equipment placement box includes a box body and an RFID automatic identification system for scanning and identifying power electronic equipment; the box body is made of lightweight shielding material, which includes a primary outer layer, a pressure-resistant filling layer, a primary shielding layer, a secondary outer layer, a main shielding layer, and a buffer layer arranged sequentially; both the primary and secondary outer layers include multiple layers of carbon fiber arranged in a cross-latitude and longitude direction; the RFID automatic identification system includes a reader and a vertically polarized flat panel antenna, which is disposed in the center of the inner wall of the top plate of the box body.

[0005] A preferred embodiment is that both the primary outer layer and the secondary outer layer comprise a carbon fiber twill surface layer, a carbon fiber straight-weave intermediate layer, and a carbon fiber twill back layer. The angle between the warp and weft directions of the carbon fiber twill surface layer and the warp and weft directions of the carbon fiber straight-weave intermediate layer is ±45°, and the angle between the warp and weft directions of the carbon fiber twill back layer and the warp and weft directions of the carbon fiber straight-weave intermediate layer is ±45°. 45°.

[0006] Preferably, the compressive strength filling layer is made of XPS foam.

[0007] Furthermore, the primary shielding layer is made of copper mesh.

[0008] Furthermore, the main shielding layer is made of copper-nickel alloy cloth.

[0009] Preferably, the buffer layer is made of EVA foam.

[0010] The present invention also provides a manufacturing process for the above-mentioned power electronic equipment placement box, which includes: Step 1: Prepare an aluminum female mold and perform surface polishing on the aluminum female mold; Step 2: Sequentially lay the carbon fiber twill surface layer, carbon fiber straight-weave intermediate layer, and carbon fiber twill back layer, which constitute the primary outer layer, on the inner side of the aluminum female mold; Step 3: Pre-impregnate the primary outer layer with an epoxy resin system; Step 4: Lay the cut primary shielding layer inside the compressive strength filling layer; Step 5: Adhere the compressive strength filling layer to the inner side of the primary outer layer; Step 6: Sequentially lay the carbon fiber twill surface layer, carbon fiber straight-weave intermediate layer, and carbon fiber twill back layer, which constitute the secondary outer layer, inside the primary shielding layer. Step 7: Pre-impregnate the secondary outer layer with an epoxy resin system; Step 8: Attach the main shielding layer to the inner side of the secondary outer layer; Step 9: Apply conductive primer to the main shielding layer; Step 10: Heat-press the buffer layer onto the inner side of the main shielding layer; Step 11: After heat curing to form the box body, demold it; Step 12: Ground the primary shielding layer and the main shielding layer; Step 13: Assemble the RFID automatic identification system.

[0011] In one embodiment, in steps 3 and 7, the resin content in the epoxy resin system is 35±3%.

[0012] Furthermore, in step 5, polyurethane adhesive is used to bond the anti-compression filling layer to the inner side of the primary outer layer.

[0013] Furthermore, in step 12, the primary shielding layer and the main shielding layer are connected to the metal hinges or metal locks of the enclosure via braided copper strips to achieve equipotential grounding.

[0014] Due to the application of the above technical solutions, the present invention has the following advantages compared with the prior art: The present invention adopts a lightweight design, which is easy to transport and can save labor costs; it has excellent impact resistance; it has good electromagnetic shielding performance, which can block external interference and prevent internal equipment signals from leaking out, thus ensuring equipment stability; it is not easy to age, corrode or deform; at the same time, it also integrates intelligent identification function, which can realize automated inventory of internal equipment, improve inventory efficiency and reduce error rate. Detailed Implementation

[0015] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0016] Example 1: A power electronic equipment placement box, including a box body and an RFID automatic identification system installed inside the box body.

[0017] The enclosure is made of lightweight shielding material and may also include a frame. The lightweight shielding material comprises, in sequence, a primary outer layer, a compression-resistant filling layer, a primary shielding layer, a secondary outer layer, a main shielding layer, and a buffer layer. When the enclosure is manufactured, the primary outer layer forms the outermost surface of the enclosure, and the buffer layer constitutes the innermost surface of the enclosure.

[0018] The primary and secondary outer layers have the same structure, both comprising multiple layers of carbon fiber arranged in a cross-sectional pattern. In this embodiment, both the primary and secondary outer layers include a carbon fiber twill surface layer, a carbon fiber straight-weave intermediate layer, and a carbon fiber twill back layer. The angle between the warp and weft directions of the carbon fiber twill surface layer and the carbon fiber straight-weave intermediate layer is ±45°, and the angle between the warp and weft directions of the carbon fiber twill back layer and the carbon fiber straight-weave intermediate layer is ±45°. 45° (i.e., reverse twill). Specifically, the carbon fiber twill surface layer uses T3003K twill carbon fiber cloth, which has high tensile strength, beautiful surface, and resistance to UV aging. The carbon fiber straight-weave intermediate layer uses T3003K straight-weave carbon fiber cloth, which provides longitudinal rigidity support and enhances flexural modulus. The carbon fiber twill back layer uses T3003K twill carbon fiber cloth, which is laid orthogonally to the carbon fiber twill surface layer. The thickness of the carbon fiber twill surface layer, the carbon fiber straight-weave intermediate layer, and the carbon fiber twill back layer is all 0.3mm. Thus, after vacuum bag compression molding, the carbon fiber twill surface layer, the carbon fiber straight-weave intermediate layer, and the carbon fiber twill back layer together form a three-layer alternating layup structure of carbon fiber with a "cross-shaped projection texture," forming a four-way continuous conductive network in the plane, greatly reducing the path of electromagnetic wave penetration and significantly improving electromagnetic closure. Experimental verification shows that compared with single-direction layup, electromagnetic shielding continuity is improved by about 40%; it can significantly improve interlaminar shear strength (ILSS≥75MPa) and avoid delamination failure. The secondary outer layer structure also forms a closed shell, enhancing the structural integrity of the enclosure.

[0019] The pressure-resistant filling layer uses lightweight XPS foam with a thickness of approximately 10mm, providing the enclosure with pressure resistance and thermal insulation.

[0020] The primary shielding layer uses a copper mesh. In this embodiment, a 200-mesh copper mesh (approximately 75 μm aperture) facing inwards from the enclosure is used, with a thickness of approximately 0.1 mm. The primary shielding layer can reflect and attenuate radio frequency energy. The aperture of this copper mesh is less than 1 / 10 of the wavelength of 922.5 MHz (λ≈325 mm → λ / 10 = 32.5 mm), meeting the minimum aperture requirement of the Faraday cage. The measured shielding effectiveness contribution is +35 dB@922.5 MHz.

[0021] The main shielding layer uses copper-nickel alloy cloth (CuNi80 / 20) with a thickness of approximately 0.1 mm, which is optimized for shielding in the 920–925 MHz frequency band. It is particularly suitable for suppressing high-frequency magnetic field components and compensates for the shortcomings of copper mesh in magnetic near-field shielding. The surface resistivity of the copper-nickel alloy cloth is <0.1 Ω / sq; the shielding effectiveness is ≥65 dB@1 GHz. With the combined effect of the copper-nickel alloy cloth and copper mesh, the total shielding effectiveness (SE) is ≥72 dB@922.5 MHz.

[0022] The buffer layer is made of EVA foam, with a thickness of 5-10mm and a density of 0.15 g / cm³, which can absorb shock and protect the internal equipment.

[0023] The total thickness of the aforementioned lightweight shielding material is 25–35 mm, and the thickness of the XPS compressive filling layer can be adjusted according to the size of the enclosure.

[0024] The RFID automatic identification system for scanning and identifying power electronic equipment includes a reader and a vertically polarized flat panel antenna. The vertically polarized flat panel antenna is located in the center of the inner wall of the top panel of the enclosure, with its signal transmission direction pointing downwards. The antenna operates at a frequency of 920–925 MHz, with a gain of 6 dBi and a half-power beamwidth of 70°. This power electronic equipment enclosure utilizes the reflective properties of the composite material interface to achieve blind-spot-free identification throughout the entire enclosure with only one vertically polarized flat panel antenna. The measured shielding effectiveness is ≥72dB@922.5MHz, effectively preventing signal leakage.

[0025] The aforementioned lightweight shielding material is a novel EXCA sandwich composite material structure, employing a combination of carbon fiber layup topology optimization, multi-layer EMI shielding film, and an internal signal reflection modulation mechanism. Because the inner wall of the enclosure is composed of multiple conductive materials (carbon fiber + copper mesh + copper-nickel cloth), electromagnetic waves undergo multiple specular reflections during propagation; the star-shaped carbon fiber structure provides isotropic reflective surfaces, ensuring uniform signal scattering to corner areas. Experimental verification shows that in an empty enclosure, the tag read rate reaches 99.8% (out of 120 tags, only 1 was missed); compared to the traditional six-antenna scheme (3 at the bottom + 3 on the side walls), this scheme reduces power consumption by 60% and simplifies wiring by 80%.

[0026] The manufacturing process of the aforementioned power electronic equipment placement box is as follows: Step 1: Mold preparation. Prepare an aluminum female mold and polish its surface.

[0027] Step 2: Outer Layer Laying. On the inside of the aluminum female mold, sequentially lay the carbon fiber twill surface layer, the carbon fiber straight-weave intermediate layer, and the carbon fiber twill back layer, ensuring precise angles.

[0028] Step 3: Prepreg Treatment. The outer layer is prepreg-treated using an epoxy resin system (such as Hexion PRIMASET™ EPON 828 + DDS curing agent). The resin content in the epoxy resin system is controlled at 35±3%.

[0029] Step 4: Embed the copper mesh. Lay the cut primary shielding layer (copper mesh) on the inner surface (top surface) of the pressure-resistant filler layer (XPS); leave soldering leads at the edges.

[0030] Step 5: Core bonding. The compression filler layer (XPS) is bonded to the inner surface of the primary outer layer using polyurethane adhesive (SikaBond®-411).

[0031] Step 6: Secondary Laying. The carbon fiber twill outer layer, carbon fiber straight-weave intermediate layer, and carbon fiber twill back layer, constituting the secondary outer layer, are sequentially laid inside the primary shielding layer.

[0032] Step 7: Apply epoxy resin pre-impregnation to the secondary outer layer to complete the outer casing encapsulation. Steps 6-7 are similar to steps 2-3.

[0033] Step 8: Attach the main shielding layer (copper-nickel alloy cloth) to the inner side of the secondary outer layer, with an overlap width of ≥10mm, and make the joints conductive with silver paste.

[0034] Step 9: Apply conductive primer (SPI Electrically Conductive Paint) inside the main shielding layer to ensure grounding continuity (PCB-GND). Step 10: Heat-press a buffer layer (EVA) onto the inside of the main shielding layer. Step 11: Overall curing. After the box is formed by heat curing, it is demolded. Specifically, it is placed in an autoclave for heat curing, and the temperature rise curve is executed as follows: room temperature → 80℃ (2h) → 120℃ (4h) → cooling and demolding.

[0035] Step 12: Grounding. The primary shielding layer (copper mesh) and the main shielding layer (copper-nickel alloy cloth) are grounded. The primary shielding layer and the main shielding layer are connected to the metal hinges or metal locks of the enclosure through braided copper strips to achieve equipotential grounding.

[0036] Step 13: Assemble the RFID automatic identification system. Install the vertically polarized antenna and reader (Impinj Speedway R420), and isolate the antenna feed line through a conduit.

[0037] Feedback from users of the aforementioned power electronic equipment storage boxes has shown the following benefits: a 52% reduction in transport weight (from 28kg to 13.4kg); a reduction in RFID inventory time from an average of 8 minutes to 45 seconds; zero misreads and zero equipment damage during six consecutive months of on-site operation; and a 37% reduction in overall operation and maintenance costs.

[0038] This power electronic equipment storage box can be expanded in the future to include packaging for military communication equipment, intelligent medicine cabinets for medical devices, transport boxes for aerospace instruments, and RFID compact shelving for smart archives.

[0039] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A power electronic equipment placement box, characterized in that: The power electronic equipment placement box includes a box body and an RFID automatic identification system for scanning and identifying power electronic equipment. The box body is made of lightweight shielding material, which includes a primary outer layer, a pressure-resistant filling layer, a primary shielding layer, a secondary outer layer, a main shielding layer, and a buffer layer arranged sequentially. Both the primary and secondary outer layers include multiple layers of carbon fiber arranged in a cross direction. The RFID automatic identification system includes a reader and a vertically polarized flat panel antenna, which is located in the center of the inner wall of the top plate of the box body.

2. The power electronic equipment placement box according to claim 1, characterized in that: Both the primary outer layer and the secondary outer layer comprise a carbon fiber twill surface layer, a carbon fiber straight-weave intermediate layer, and a carbon fiber twill back layer. The angle between the warp and weft directions of the carbon fiber twill surface layer and the warp and weft directions of the carbon fiber straight-weave intermediate layer is ±45°. The angle between the warp and weft directions of the carbon fiber twill back layer and the warp and weft directions of the carbon fiber straight-weave intermediate layer is ±45°. 45°.

3. The power electronic equipment placement box according to claim 1, characterized in that: The compressive filling layer is made of XPS foam.

4. The power electronic equipment placement box according to claim 1, characterized in that: The primary shielding layer is made of copper mesh.

5. The power electronic equipment placement box according to claim 1, characterized in that: The main shielding layer is made of copper-nickel alloy cloth.

6. The power electronic equipment placement box according to claim 1, characterized in that: The buffer layer is made of EVA foam.

7. A manufacturing process for a power electronic equipment placement box as described in claim 2, characterized in that: The manufacturing process of the power electronic equipment placement box includes: Step 1: Prepare an aluminum female mold and perform surface polishing on the aluminum female mold; Step 2: Sequentially lay the carbon fiber twill surface layer, carbon fiber straight-weave intermediate layer, and carbon fiber twill back layer, which constitute the primary outer layer, on the inner side of the aluminum female mold; Step 3: Pre-impregnate the primary outer layer with an epoxy resin system; Step 4: Lay the cut primary shielding layer inside the compressive strength filling layer; Step 5: Adhere the compressive strength filling layer to the inner side of the primary outer layer; Step 6: Sequentially lay the carbon fiber twill surface layer, carbon fiber straight-weave intermediate layer, and carbon fiber twill back layer, which constitute the secondary outer layer, inside the primary shielding layer. Step 7: Pre-impregnate the secondary outer layer with an epoxy resin system; Step 8: Attach the main shielding layer to the inner side of the secondary outer layer; Step 9: Apply conductive primer to the main shielding layer; Step 10: Heat-press the buffer layer onto the inner side of the main shielding layer; Step 11: After heat curing to form the box body, demold it; Step 12: Ground the primary shielding layer and the main shielding layer; Step 13: Assemble the RFID automatic identification system.

8. The manufacturing process of the power electronic equipment placement box according to claim 7, characterized in that: In steps 3 and 7, the resin content in the epoxy resin system is 35±3%.

9. The manufacturing process of the power electronic equipment placement box according to claim 7, characterized in that: In step 5, polyurethane adhesive is used to bond the anti-compression filling layer to the inner side of the primary outer layer.

10. The manufacturing process of the power electronic equipment placement box according to claim 7, characterized in that: In step 12, the primary shielding layer and the main shielding layer are connected to the metal hinges or metal locks of the enclosure via braided copper strips to achieve equipotential grounding.