Analysis of Conductivity Differences Between Copper and Aluminum Terminals

Copper and aluminum are commonly used as core conductive materials for terminals, and their physical property differences directly impact the reliability of the connection system. Copper has a conductivity of approximately 58.0×10^6 S/m, which is significantly higher than aluminum’s 37.7×10^6 S/m. This allows copper terminals to carry higher currents and generate less heat at the same cross-sectional area.
It is worth noting that aluminum easily forms a high-resistance oxide layer (Al₂O₃) in air, which can cause the contact resistance to increase to 3–5 times the initial value over time. Therefore, antioxidant coatings or sealing processes are required to maintain long-term stability.

In environments with frequent vibrations or large temperature variations, copper terminals are recommended due to their superior ductility and resistance to creep, which help mitigate the reduction in contact pressure caused by material deformation.
Additionally, direct contact between copper and aluminum can create a galvanic potential difference of about 0.4V. In humid conditions, this may trigger a micro-galvanic cell effect, accelerating the corrosion of aluminum terminals. In engineering applications, tin-plated transition layers or specialized copper-aluminum composite terminal structures are commonly used to block ion migration paths and prevent connection failure due to electrochemical corrosion.
For high-load scenarios, it is important to leverage the lightweight advantage of aluminum and the high conductivity of copper, achieving a performance balance through structural optimization.