In the field of electrical equipment, transformers are indispensable core components in power transmission and distribution systems. With the continuous advancement of materials science, copper foil, aluminum foil, and composite foil have been widely used in transformer manufacturing. This article provides a detailed comparison of the application differences among these three types of foil materials in transformers from the perspectives of performance characteristics, application scenarios, and cost-effectiveness, helping users better understand their advantages and applicability.

Application of Copper Foil in Transformers

Copper foil is widely used in high-end transformer manufacturing due to its excellent electrical conductivity, good thermal stability, and superior mechanical strength. Its main advantages include:

• High Conductivity: Copper has an electrical conductivity of approximately 58 MS/m, the highest among all non-precious metals, ensuring minimal energy loss during transformer operation.
• Good Thermal Stability: Copper performs stably at high temperatures, making it suitable for high-power and high-current environments.
• Excellent Workability: Copper foil is easy to weld and connect, making it suitable for complex structural designs.

The main drawbacks are its high cost and relatively heavy weight.

Application of Aluminum Foil in Transformers

Aluminum foil is widely used in medium- and low-voltage transformers and cost-sensitive projects due to its lightweight and low-cost characteristics. Its advantages include:

• Low Cost: Aluminum is significantly cheaper than copper, making it the preferred choice for budget-limited projects.
• Lightweight: Helps reduce the overall weight of equipment, facilitating transportation and installation.
• Strong Corrosion Resistance: The surface forms an aluminum oxide layer, enhancing stability in harsh environments.

However, its conductivity is only about 61% of copper's, so a larger cross-sectional area is required to achieve the same electrical performance.

Application of Composite Foil Materials in Transformers

Composite foil is a new type of material formed by laminating copper with aluminum or other metals, combining the advantages of multiple metals. Its characteristics include:

• Balance of Cost and Performance: Offers good conductivity while reducing material costs.
• Structural Diversity: Thickness and layers can be customized according to usage needs, increasing design flexibility.
• Moderate Weight: Lighter than pure copper, better performance than pure aluminum—ideal for projects with both performance and cost considerations.

The main challenge lies in the treatment of composite interfaces and process control, which must ensure long-term stability.

Comparative Summary of Application Differences

When selecting foil materials for transformers, it is essential to consider performance requirements, budget constraints, and operating environments. Copper foil is suitable for high-end equipment demanding high performance, aluminum foil is ideal for the cost-conscious mid- to low-end market, while composite foil offers an optimal solution for balancing performance and cost. Understanding these materials' characteristics and applications helps optimize transformer design and improve overall system efficiency.