Every improvement in new energy vehicle (NEV) safety is driven by the combined progress of regulations, technology, and materials—and copper plays an irreplaceable role in this evolution.
As the global NEV industry expands rapidly, China has made significant advances during its 14th Five-Year Plan period by strengthening regulatory standards, accelerating technological innovation, and raising corporate safety awareness. These efforts have led to notable improvements in the safety and reliability of three core systems: batteries, electric motors, and wiring harnesses. Throughout this process, copper materials—thanks to their excellent electrical conductivity, thermal performance, corrosion resistance, ductility, and flexibility—have provided material-level solutions to mitigate risks such as thermal runaway, electrical arcing, corrosion, and mechanical fatigue.
Outstanding Performance Building a Multilayer Safety Barrier
Copper’s widespread use in NEVs is rooted in its superior physical and chemical properties, which make it an ideal material for critical electric vehicle systems.
In terms of electrical conductivity, copper ranks second only to silver, with a resistivity as low as 1.7 × 10⁻⁸ Ω·m. This enables highly efficient power transmission within vehicles while minimizing energy losses.
Copper’s thermal conductivity reaches 386 W/m·K, a critical advantage for battery systems and drive motors that require effective thermal management. Efficient heat dissipation helps prevent localized overheating and significantly reduces the risk of thermal runaway.
Mechanically, copper offers strong tensile strength (≥210 MPa) and high elongation (≥35%), allowing it to be easily processed into various wire shapes and specifications to meet complex wiring requirements.
Copper also demonstrates excellent corrosion resistance. Its surface can be tin-plated or silver-plated to further enhance oxidation resistance, ensuring long-term stability and reliability in demanding electrical environments.
Efficiency Gains From High-Voltage Architectures to Battery Innovation
As 800 V high-voltage architectures gain traction across the NEV sector, the importance of copper continues to rise. Higher voltage systems place stricter demands on connection components, making copper the preferred material for high-voltage busbars and connectors due to its superior conductivity and low contact resistance. Copper’s high melting point (1083°C) also provides additional safety margins against potential arcing failures.
In drive motors, copper windings are essential for handling high currents efficiently. Corporate test data show that motors using high-purity copper rotors can improve efficiency by approximately 8%, while reducing operating temperatures by nearly 10°C under extreme conditions such as sustained high-speed driving.
In battery technology, the trend toward ultra-thin copper foil has significantly enhanced energy density. Studies indicate that reducing copper foil thickness by 1 μm can increase battery energy density by about 2%. When foil thickness is reduced from 8 μm to 4 μm, energy density can rise by roughly 8%, translating into more than 50 km of additional driving range at the same battery volume.
Safety and Reliability Ensuring High-Voltage Integrity and Thermal Runaway Prevention
Copper plays multiple critical roles in NEV safety, particularly in high-voltage connectivity and thermal runaway prevention.
High-voltage connection systems serve as the “arteries” of electric vehicles, distributing power to all major components. Owing to its excellent conductivity and low contact resistance, copper is widely used in high-voltage busbars and connectors, with many 800 V NEV platforms already adopting high-purity copper busbars in core circuits.
Copper is also increasingly used in battery safety structures such as explosion-proof valves and directional pressure relief channels. Its plasticity and machinability allow engineers to design pressure relief components that open precisely at predefined thresholds, safely venting gas and heat away from the passenger compartment during thermal runaway events. In some domestically developed battery packs, specially designed copper alloy relief valves have become a key safety feature.
Precision sensing and monitoring represent another frontline of safety. High-purity copper is the base material for high-accuracy current sensors, whose stability and linearity are essential for battery management systems to monitor battery conditions accurately and provide early warnings of thermal runaway.
High-purity copper foil further enhances intrinsic battery safety at the material level. With purity levels typically above 99.9%, it minimizes localized electrochemical corrosion and abnormal reactions caused by impurities, ensuring uniform current distribution and strong bonding with anode materials such as graphite. This suppresses lithium dendrite formation and significantly reduces the risk of internal short circuits.
In addition, copper foil’s excellent electrical and thermal conductivity enables rapid current flow and heat dissipation, preventing localized overheating. Its mechanical strength and ductility also help maintain structural integrity during repeated battery expansion and contraction, preserving electrical continuity and reducing failure risks. During high-rate charging and discharging, the foil’s low resistance minimizes ohmic heating, providing stronger thermal control and enhancing battery safety under high-performance conditions.
Source：Tencent