#fuse holders

In fuse holder design, terminals are the core components connecting the fuse to the circuit. Their performance directly affects the safety and stability of the entire electrical system. With over 20 years of experience in the industry, I understand that terminals are not just conductors—they ensure the long-term reliability and safety of devices. This article will analyze the material characteristics, electrical performance, and structural functions of silver-plated copper terminals in fuse holders, supplemented with real customer examples.

1. Material Characteristics and Electrical Performance

Fuse holder terminals are typically made of copper with silver plating, which provides significant advantages in conductivity, durability, and soldering reliability.

1. Copper Core: High Conductivity and Low Heat Resistance

Copper has a conductivity of approximately 97% IACS, effectively reducing contact resistance and heat generation.

Customer Experience: In an industrial power supply project, conventional tin-plated terminals caused terminal overheating and poor fuse contact during long-term operation. Replacing them with copper terminals reduced contact resistance, decreased temperature rise by about 5°C, and stabilized circuit performance.

Copper’s excellent thermal conductivity allows rapid heat dissipation in high-current environments, reducing overheating and thermal fatigue—a critical factor for high-power power supplies and automation equipment.

2. Silver Plating: Enhanced Conductivity and Protection

Silver-plated terminals improve performance in several ways:

Lower contact resistance: Silver is one of the best conductors, further reducing resistance between the terminal and the fuse.

Oxidation resistance: The silver layer protects the copper core from air and moisture corrosion. Stable contact: Maintains excellent contact performance even after frequent insertion and removal.

Improved soldering reliability: Silver enhances solder joint quality, reducing the risk of cold joints.

Example: In an outdoor industrial sensor project, unplated copper terminals developed oxidation and contact failure after six months. Switching to silver-plated copper terminals maintained low contact resistance and stable operation under humid and dusty conditions. In medical testing equipment, silver-plated terminals also ensured signal stability, improving measurement accuracy.

2. Terminal Structure and Function

Terminal structure directly affects the lifespan and safety of fuse holders. Effective terminal design ensures tight contact while maintaining elasticity and high-current performance.

1. Contact Surface Design

Terminals must maintain tight contact with both ends of the fuse. Flat and evenly clamped contact surfaces ensure stable current conduction.

Experience Example: In an industrial power supply project, uneven terminal surfaces caused slight fuse looseness. After redesigning the contact surface with silver-plated copper terminals, the fuse contact became stable and reliable.

2. Elasticity, Clamping Force, and High-Current Performance

Terminals need sufficient elasticity for repeated fuse insertion and removal. At the same time, they must maintain low temperature rise under high current to prevent overheating that could damage the fuse or terminal. Material choice, terminal thickness, and elasticity design must be carefully optimized.

Case Study: In an industrial control cabinet project, terminals carried high current while undergoing frequent insertion and removal. Silver-plated copper terminals provided stable clamping force, smooth operation, and temperature rise remained within safe limits, ensuring reliable operation.

3. Application Value and Conclusion

Based on years of practical experience, silver-plated copper terminals in fuse holders provide:

Reliable electrical connection: Low contact resistance ensures long-term stability.

High system safety: Oxidation resistance and low heat generation reduce failure rates.

Long service life: Material and surface treatment provide fatigue and insertion durability.

Easy maintenance: Proper clamping force and elasticity ensure smooth insertion and removal.

These advantages make silver-plated copper terminals widely used in industrial power supplies, automation systems, home appliances, laboratory instruments, and outdoor electrical equipment, providing a solid safety barrier for the circuit.

Through years of technical practice, I have seen that copper core ensures high conductivity and heat dissipation, while silver plating provides oxidation protection, low contact resistance, and soldering reliability. Combined with a well-designed terminal structure, fuse holders achieve high reliability, low failure rate, and long lifespan. Every improvement in material or structure contributes to stable device operation. Silver-plated copper terminals are not only conductors but also essential components ensuring device safety, reliability, and efficiency.

With the development of modern power and electronics systems, devices are becoming more compact and versatile, demanding higher compatibility from fuse holders. For manufacturers and system integrators, designing a universal fuse holder compatible with both 5×20mm (European) and 6.3×32mm (American) fuses significantly reduces SKUs, simplifies supply chain management, and improves global adaptability.

This article explores key design principles for multi-size compatible fuse holders, including:

Multi-slot terminal design for both fuse sizes

Spring pressure self-adjustment mechanisms

Real-world case applications

Material selection and tolerance control

Future trends toward intelligent compatibility

1. Market Demand for Size Compatibility

5×20mm fuses are prevalent in small electronics, while 6.3×32mm fuses dominate in industrial and household applications. Clients increasingly demand dual-compatibility for:

Inventory optimization

Global certification compliance

Improved user experience

Reduced support costs

2. Slot Geometry and Dual-Fit Design

The core of universal design lies in "dimensional absorption mechanisms" — the ability to compensate for varying fuse sizes while ensuring solid contact.

Common design tactics:

Dual-stage contact slots: Tiered recesses that securely hold both short and long fuses

Floating guide rails: Adaptive rail design to accommodate different fuse lengths

U-shaped contact springs: Enveloping contacts that grip both diameters with precision

3. Spring Pressure Adjustment Solutions

Fuse holders must provide consistent contact pressure (typically 1.5–3N) regardless of fuse size. Poor pressure can cause contact resistance, heat buildup, or arcing.

Engineering options include:

Nonlinear spring geometry (e.g., stepped or torsion springs)

Compressible conductive pads behind contact points

Multi-point contact zones to distribute pressure and ensure reliability

4. Case Study: PCB-Mount Universal Fuse Holder

A client required a PCB-mounted fuse holder for both sizes. The solution featured:

Component

Design

Housing

UL94V-0 PBT plastic

Spring

Silver-plated phosphor bronze

Slot design

Tiered contacts with floating guides

PCB fit

±0.5mm tolerance

Lifespan

>100 cycles, ≤20% resistance variation

This design achieved CE and UL certification and was widely used in inverters, smart meters, and industrial control systems.

5. Material & Precision Considerations

Material selection:

Phosphor bronze for high elasticity and conductivity

Silver plating for oxidation resistance

Stainless steel for harsh environments (with plating)

Manufacturing tolerances:

Stamping precision within ±0.05mm

Plastic molding accuracy within ±0.02mm

Heat treatment to prevent permanent deformation

6. Future Outlook: Smart Fuse Holders

Emerging developments include:

LED fuse blow indicators

Remote monitoring terminals

Standardized pin layouts for cross-compatibility

In modern electronic equipment and industrial systems, the fuse holder is not only a vital component for circuit protection but also a high-risk point for direct human interaction. As safety requirements rise, the anti-electric shock design and misoperation protection mechanism of fuse holders have become key topics of interest for B2B clients.

This article elaborates on:

Electrical hazard analysis of fuse holders

Engineering of safety shutters and anti-reverse structures

Whether fuse holders are live when removing the fuse, and how to prevent shock risks

Practical case studies

Design extensions: visual, tactile, and warning integrations

Conclusion: Safety design is a system-level task

1. Risk Analysis: Structural Hazards and Application Scenarios

Fuse holders operate at voltages ranging from AC 250V to DC 1000V and currents from a few amps up to several dozen. Common operational risks include:

Exposed live parts when replacing the fuse

Untrained personnel unintentionally touching live terminals

Improper operation sequence, e.g., pulling fuses under load or inserting the wrong size

Proper safety design must address these potential failure points.

2. Safety Shutters & Anti-Reverse Structural Design

Safety shutters are mechanical devices designed to shield live contacts when not in use.

Common structural solutions:

Push-rod linked shutters: Automatically open when a fuse is inserted, close when removed.

Spring-return blockers: Cover live areas when no fuse is present.

Dual-action unlocking: Requires special tools or dual-hand operation to open.

Anti-reverse mechanisms prevent incorrect fuse orientation or use of incompatible fuse sizes:

Slot-limited cavities for specific fuse dimensions (5×20mm or 6.3×32mm)

Asymmetric polarizing guides to prevent reversed insertion in DC systems

Redundant confirmation mechanisms like dual-end push unlock

3. Are Fuse Holders Live When Fuses Are Removed?

Yes — in many designs, terminals may still be energized even when the fuse is removed.

Design solutions include:

Load-side disconnect linkage: Auto-disconnects downstream power during fuse extraction.

Arc suppression design: Use of high-temp resistant materials, spring-loaded separation, or arc chambers.

Double insulation zones: Multi-layered plastic isolation around contact points.

Grounded shielding enclosures: Especially for communication or industrial control systems.

4. Practical Case Studies

Medical device application: Fuse holders with key-lock to prevent unauthorized replacement

Solar inverter application: DC1000V fuse holders with arc-suppression slots and silver-plated contacts

5. Extended Design Integration

Visual indicators (LED, colored flags) for fuse status

Tactile feedback on insertion/removal (click response, resistance control)

Permanent safety warnings printed on the fuse holder housing

6. Conclusion: Safety is a System Engineering Effort

Fuse holders may be small, but they play a critical role in operational safety and system uptime. From structural shielding to controlled user interaction, anti-shock design is not an afterthought—it's the core of product reliability.

You’ve Probably Used a Fuse Holder Made Here!

Introduction

With the rapid development of diverse electronic and power distribution systems, customers now demand fuse holders that support modularity, cross-compatibility, and high adaptability. In OEM, aftermarket, and international markets, having separate fuse holders for each fuse size is costly and inefficient.

Multi-specification compatible fuse holders address this issue by allowing a single design to support both 5×20mm and 6.3×32mm fuses. These holders must maintain stable contact, mechanical retention, and standard dimensions. This article explores the core structural innovations: dual-compatible clip designs, automatic pressure-adjustable contacts, standardized housing for universal mounting, and anti-misplug limiters.

1. Dual-Size Compatible Clip Design for 5×20mm & 6.3×32mm Fuses

1.1 Compatibility Challenges

5×20mm fuses are common in small electronics, while 6.3×32mm fuses are used in high-power or industrial systems. The dimensional difference (length and diameter) means traditional fuse holders require separate part numbers.

1.2 Structural Design Principles

Modern fuse holders adopt multi-stage contact and retention structures or sliding internal slots that automatically adjust for fuse size.

Key Features:

Two-step limit structure: Lower step for 5×20mm, upper step for 6.3×32mm

Flexible contact clips that retract or expand as needed

Multi-point contact zones for stable current conduction

Case Study:

A power adapter manufacturer consolidated two SKUs into one universal holder, cutting BOM costs by 18% and improving assembly throughput by 32%.

2. Auto-Adjusting Contact Pressure Design

2.1 Insertion Force Imbalance Risks

Varying fuse diameters can lead to:

Low pressure → high contact resistance and heat

Excess pressure → glass tube damage, hard insertion

2.2 Automatic Spring-Based Adjustment

Advanced holders use flex-jointed or spring-assisted contacts:

Flexible hinge base absorbs dimensional variance

Tail-end springs maintain pressure across all sizes

Materials like heat-treated phosphor bronze for fatigue resistance

Performance Benefits:

Maintains <10 mΩ contact resistance

Survives 500+ insert/remove cycles

Reduces user error and assembly damage

Practical Testing:

This structure kept resistance variation under 10% between 40°C and 85°C for both fuse sizes — superior to rigid clip designs.

3. Standardized Housing Dimensions for Universal Mounting

3.1 Multi-Device Integration Needs

Devices use different mounting methods: panel-mount, PCB-soldered, DIN-rail, screw-fixed. To simplify manufacturing, one housing must fit many.

3.2 Modular Size Implementation

Designers apply:

Unified mounting holes (e.g., Φ10.3mm, 19×12mm)

Interchangeable mounting brackets

Sliding grooves for clip-in flexibility

Modular Example:

scss复制编辑[Module A: PCB Plug-in] ─┬─ Terminal block wiring 

├─ Panel snap fit 

└─ DIN rail clip mount 

Customer ROI:

An industrial controls company standardized its PLC line with one universal fuse holder design, reducing part types by 50% and improving field repair efficiency.

4. Anti-Misplug Design: Fuse Length Limiting Structures

4.1 Insertion Errors in the Field

Common errors:

Short fuse in long-slot holder → loose contact

Oversized fuse → latch failure or contact arcing

Wrong fuse rating → safety risk

4.2 Built-In Length Limiters

Universal fuse holders include:

Dual-position stop grooves for exact length matching

Spring-tensioned limit walls that adapt to size

Optional colored guides to distinguish slot types

Engineering Result:

A medical device OEM reduced service errors by 60% using these limiters and color-coded guides, improving product safety and end-user confidence.

5. Engineering Recommendations and Future Trends

5.1 Intelligent Fuse Detection

Future models may embed micro-sensors (resistance-based or magnetic) to detect fuse size/type and communicate with the system MCU via I²C or CAN.

5.2 Platform-Based Modular Architecture

Develop a core-standardized fuse holder platform, with swappable:

Fuse blow indicators

Remote monitoring modules

EMI filters for sensitive circuits

5.3 Certification-Conscious Global Design

Ensure cross-certification readiness: UL, IEC, TUV. Structure should meet global electrical safety and mechanical compatibility norms.

Conclusion

Multi-specification compatible fuse holders represent the next evolution in electronic protection. By integrating dual-size retention, pressure-adjustable contacts, standardized mounting, and anti-misplug mechanics, manufacturers can streamline designs, reduce SKUs, and boost customer satisfaction.

Looking ahead, compatibility will extend beyond mechanical to intelligent systems — enabling fuse holders to integrate seamlessly into smarter, safer, and more modular electrical ecosystems.

Introduction

In modern automotive electrical systems, fuse holders play a critical role in overcurrent protection. Their structural robustness and electrical reliability directly impact the safe operation of the entire vehicle. Particularly in automotive-grade applications, fuse holders are frequently exposed to intense vibration, extreme temperature cycles, and fluctuating electrical loads. Therefore, they must not only meet basic electrical specifications but also offer excellent vibration resistance and stable contact performance to ensure long-term reliability.

This article explores structural design and verification methods for automotive-grade fuse holders, focusing on features such as barb-shaped contact clips with silver plating, anti-loosening locking mechanisms, vibration testing standards (ISO 16750 / QC/T 413), and resistance stability under thermal cycling.

1. Barb-Shaped Contact Clips + Silver Plating: Ensuring Long-Term Reliable Contact

1.1 Principle of Barb-Shaped Contact Clips

Common contact structures in fuse holders include straight-type, V-shaped, U-shaped, and barb-shaped clips. Among these, barb-shaped clips are ideal for high-reliability automotive applications due to their excellent locking ability, large contact area, and vibration resistance.

These barb-shaped structures act like hooks: as the fuse leg is inserted, the barb locks it in place while maintaining consistent pressure. Advantages include:

Enhanced mechanical retention against vibrations.

Multi-point contact for better current distribution.

Maintains locking even with fatigue or deformation.

1.2 Silver Plating for Enhanced Conductivity and Anti-Oxidation

Applying silver plating to contact surfaces is a key process:

Silver has very low resistivity (1.59 µΩ·cm), ensuring excellent conductivity.

Silver resists oxidation in high-temperature or humid environments.

Helps suppress micro-arcing and extends service life.

Engineering example: A new energy vehicle manufacturer replaced tin-plated contacts with silver-plated barb clips in its fuse holders. This reduced the contact area temperature by 22°C, improving thermal stability significantly.

2. ISO 16750 & QC/T 413: Automotive Vibration Testing Standards

2.1 Overview of ISO 16750

ISO 16750-3 is an international standard for mechanical testing of automotive electronic components. Key vibration criteria include:

Frequency range: 10 Hz to 2000 Hz

Acceleration: 0.5 g to 30 g

Both sine and random vibration simulations

Testing in all three directions (X, Y, Z)

2.2 QC/T 413: China’s Automotive Fuse Holder Standard

QC/T 413 sets mechanical requirements such as:

Sine sweep from 10 Hz to 55 Hz

2 hours per axis

Max vibration amplitude ±1.5 mm

Post-test functionality must be intact; contact resistance change <20%

2.3 Testing Setup & Practical Verification

Testing is conducted using three-axis vibration tables with real-time contact resistance monitoring. This simulates real road conditions like potholes and engine vibrations.

Case study: A commercial truck manufacturer experienced contact loosening after 12,000 km of operation. Upgrading to a locked, barb-shaped contact design passed 24-hour ISO 16750 testing with zero failures.

3. Locking Mechanism Design: Preventing Accidental Disconnection

3.1 Why a Locking Mechanism Is Necessary

Fuse holders located near the engine or chassis endure constant shock. Common issues with standard push-fit contacts:

Gradual loosening under vibration

Increased resistance and heat due to poor contact

Improper assembly causing intermittent faults

3.2 Dual Lock Design Approach

Modern automotive fuse holders feature dual locking mechanisms:

Primary lock: Snap-in or push-pull latch for physical retention

Secondary limiter: Prevents pull-out under external force

Optional anti-misplug tabs for diagnostic or mission-critical fuses

3.3 Insertion/Withdrawal Force Verification

Ideal insertion force: 30–60 N Retention force (locked): ≥80 N Endurance: At least 10 mating cycles with consistent performance.

4. Resistance Performance in Thermal Cycling Conditions

4.1 Structural Deformation Under Temperature Fluctuations

Vehicle systems operate between -40°C and +125°C. This expansion and contraction may affect contact pressure and increase resistance. Issues include:

Higher resistance during cold start

Oxidation at high temperatures

Fatigue or loss of contact force

4.2 Thermal Cycle Test Procedure

Following ISO 16750 or IEC 60068:

Temperature range: -40°C to 125°C

Hold time: 30–60 mins per extreme

Cycles: 50–100

Real-time monitoring of resistance under load

4.3 Performance Criteria

Contact resistance change <20%

No deformation, cracking, or detachment

Insertion force variation <10%

Electrical functionality remains intact

5. Additional Engineering Recommendations

5.1 Hot-Swap Support

Implement hot-swappable contact rail structures with spring-loaded or sliding rails to avoid arcing during in-service replacement.

5.2 Flame-Retardant Housing

Use UL94 V-0 rated PA66 + GF30 materials for better flame resistance, UV stability, and structural strength in harsh environments.

5.3 Visual Color Coding

Introduce a color code system (e.g., red/yellow/blue) to distinguish fuse sizes or types, improving field technician efficiency.

Conclusion

Automotive-grade fuse holders must offer more than basic connectivity — they serve as a backbone of reliable vehicle electrical safety. By integrating barb-shaped contacts, silver plating, dual locking mechanisms, and rigorous thermal-vibration validation, manufacturers can ensure stable, long-term performance even in the harshest conditions.

With trends in automotive electrification and smart control systems, fuse holders are evolving toward integrated monitoring, diagnostic capability, and robust environmental resilience. Future-proofing fuse holder design will depend on combining mechanical integrity, electrical performance, and intelligent adaptability.

20 Years of Refinement for One Perfect Fuse Holder— Ready to Be Amazed?

Introduction In applications such as new energy systems, rail transit, and automotive engine compartments, fuse holders often face temperature cycles from –40 °C to +150 °C or even higher. High-temperature environments not only accelerate material aging but also cause differential thermal expansion that can loosen mating parts and raise contact resistance, thus undermining circuit protection and overall system reliability. Based on years of experience in developing electronic switches and protection components, this article focuses on two core topics—thermal-expansion matching and heat-dissipation design—and, through representative case studies and key design points, delves into material selection, structural optimization, and thermal-management schemes for fuse holders in high-temperature environments.

I. Key Challenges for Fuse Holders in High-Temperature Environments

Material Degradation Engineering plastics tend to crack under stress and distort dimensionally when exposed long-term to temperatures above 125 °C. Springs creep at elevated temperatures, reducing preload force over time.

Thermal-Cycle–Induced Contact Failure Repeated temperature swings (±50 °C or more) cause relative displacement between components with different CTEs (coefficients of thermal expansion), leading to loosened pins, springs, and housing interfaces.

Local Hot Spots and Heat Accumulation Under heavy currents or poor ambient cooling, temperatures around the fuse can spike above 200 °C during melting, exacerbating nearby material degradation.

Mechanical Reliability and Safety Requirements Sectors like rail and automotive impose strict vibration, shock, and fire-resistance standards, so heat-dissipation and sealing designs must also satisfy flame-retardance and structural-strength criteria.

II. Thermal-Expansion Matching Design

1. Comparison of Material CTEs

2. CTE-Matching Strategies for Pins, Springs, and Housing

Housing vs. Spring Choose PPS or LCP for the housing (CTE ≈12–15 ×10⁻⁶/K) to match stainless-steel springs (CTE ≈12 ×10⁻⁶/K), keeping thermal-cycle displacement under 20 µm.

Pins vs. Housing For copper-alloy pins (CTE ≈17 ×10⁻⁶/K) paired with PA66-GF30 housing (CTE ≈15 ×10⁻⁶/K), introduce a soft-transition buffer—such as an annular micro-wall or multi-wedge compression zone—at each pin hole to absorb about 5 µm per 10 K of differential expansion.

Ceramic Insert Application In ultra-high-temperature scenarios (>150 °C), embed low-CTE ceramic inserts in critical conductive paths. The metal-ceramic composite structure can reduce surrounding differential expansion to under 2 µm per 10 K.

3. Structural Buffers and Stress-Relief Features

Micro-corrugated-tube transition: Machine tiny corrugations at the pin–spring interface to provide both conductivity and displacement absorption.

Annular soft pad: Insert high-temperature silicone or rubber pads at the pin base or spring seat–housing interfaces for added thermal-cycle cushioning.

Segmented snap-fit design: Divide the housing into inner and outer layers, linked by metal clips or locking rings that allow the inner layer to slide along guiding slots during thermal expansion, eliminating stress concentration.

III. Heat-Dissipation Design and Thermal Management

1. Base Heat-Sink Fin Design

Material selection: Use high-thermal-conductivity aluminum alloys (7075 or 6063) for the base (CTE ≈23 ×10⁻⁶/K), constrained by design features to mate reliably with a PPS or LCP housing.

Fin dimensions and spacing: For 100 A-class applications, fins should be ≥1.5 mm thick, 15 mm tall, with 8 mm spacing—boosting convective area and reducing local temperature by 5–10 °C.

Assembly method: Employ cold-riveting or insert casting so the aluminum fins form a monolithic structure with the plastic base, ensuring minimal and stable thermal paths.

2. Metal-Insert Heat-Sink Solutions

Copper-alloy heat-sink inserts: Mold cavities near the fuse-contact region, then insert C1100 copper pieces that are welded or mechanically locked to the pins and springs, swiftly channeling melting-event heat away.

Thermal pads and conductive grease: In multi-way fuse-holder modules, place 0.5 mm thermal-pad layers or conductive grease between the metal inserts and fins to cut interface thermal resistance by at least 30%.

Embedded thermal pillars: Bury multiple Φ2 mm×20 mm copper pillars in the plastic base to connect to the finned cover, forming a three-dimensional thermal path that uniformizes temperature distribution.

3. Thermal Simulation and Validation for Typical Applications

Case Study A: Diesel Engine Control Box Fuse Holder Ambient: –40 °C to +130 °C, confined enclosure. Design highlights: PPS housing + copper inserts + aluminum base fins. Thermal simulation shows a maximum surface temperature of <95 °C under 50 A continuous current.

Case Study B: 1500 V DC Inverter High-Voltage Circuit Ambient: –20 °C to +85 °C, high-altitude conditions. Innovations: Embedded ceramic composite thermal pillars, annular cooling channels, and integrated base fins. Measured temperature rise <40 °C after an 80 A short-circuit melt (500 ms), well below material deformation thresholds.

IV. Other Critical Design Elements

Arc Isolation and Fire-Resistance During high-temperature melts, arcs occur. Introduce ceramic partition plates or metalized quartz shards to form an arc chamber, isolating arc energy locally and using nearby fins to dissipate it rapidly.

Flame-Retardance and Aging-Life Control Select UL 94 V-0 (or higher) flame-retardant materials. Conduct accelerated-aging tests (150 °C, 500 h; 1 000 thermal cycles) on plastics and springs to ensure contact resistance remains <10 mΩ after 100 000 insertions.

Dust-Proofing, Water-Proofing, and Sealing High-temperature environments often involve dust or humidity. Design to IP 67: Silicone O-rings between housing and base. Replaceable post-melt cover that allows “hot-swap” maintenance without power shutdown.

V. Conclusion and Future Outlook

Under high-temperature conditions, fuse-holder reliability and service life hinge on both CTE matching and heat-dissipation design. By:

Precisely matching the thermal-expansion coefficients of pins, springs, and housings with structural buffers;

Employing base fins, metal-inserts, and three-dimensional thermal paths;

Integrating arc isolation, flame-retardance, accelerated-aging, and sealing features—

one can markedly enhance fuse-holder stability across –40 °C to +150 °C cycles or beyond. Looking forward, the maturation of low-CTE composites and graphene-based thermal materials, together with digital-twin thermal simulations and online monitoring, will further boost high-temperature adaptability of fuse holders—laying a stronger protection foundation for electric vehicles, high-speed rail traction, and avionics.