What makes a connector heat-resistant?

Specifically, heat resistance mainly depends on the following three dimensions:

1. Insulating housing material (plastic)
This is the "skeleton" of the connector, responsible for fixing the terminals and insulation. Its heat resistance is usually measured by the Relative Temperature Index (RTI), which represents the temperature at which the material's performance decreases by 50% over 100,000 hours. Choosing materials with a high RTI value is key to resisting long-term thermal aging.

Common high-temperature plastic materials include:
LCP (Liquid Crystal Polymer): Offers the best overall performance, with a temperature resistance of 290°C - 320°C, often used in SMT components or high-temperature automotive environments.
PPS (Polyphenylene Sulfide): High rigidity and dimensional stability, with a heat distortion temperature of about 260°C.
High-temperature Nylon (such as PA6T, PA46): Balances toughness and heat resistance, with a temperature resistance of about 260°C - 300°C.
PBT (Polybutylene Terephthalate): Normal heat resistance, with a temperature resistance of about 230°C, commonly used in standard electronic devices.

2. Metal Terminal Materials (Copper Alloys)
This is the "nerve" of the connector, responsible for conducting electricity. At high temperatures, ordinary metals are prone to stress relaxation, which can lead to a decrease in contact elasticity, causing signal interruptions or increased resistance. Therefore, it is crucial to choose copper alloys with strong resistance to stress relaxation.
Beryllium Copper: Excellent elasticity, superior fatigue resistance and heat resistance compared to brass, making it an ideal choice for high-reliability, wide-temperature applications.
Phosphor Bronze: Harder than brass, capable of maintaining elasticity over a longer period, commonly used in situations where the operating temperature is below 300°F (approximately 149°C).

3. Overall Thermal Management Structure Design
This is the connector's "temperature control system." The Joule heat generated by the current is the main source of internal temperature rise, and a good structure can effectively dissipate the heat, preventing the internal temperature from becoming too high.
Large spacing design: Increasing the physical distance between terminals helps with heat dissipation through air convection.
Heat dissipation structure: Some high-power or new energy vehicle connectors adopt a metal casing or heat sinks, using conduction and convection to carry away heat.

The heat resistance of a connector is the result of the combined effect of materials and structure: 
Plastic is the foundation: it determines the maximum environmental temperature the connector can withstand (for example, whether it can tolerate high-temperature reflow soldering). 
Metal is the core: it determines whether the connector can maintain reliable elastic contact under high-temperature power-on conditions for an extended period. 
Structure is key: it determines the rate of internal heat accumulation, ultimately affecting the actual operating temperature.