Analysis of key items in the design of high-voltage connectors

Temperature rise is one of the most important design key items in connector design. Abnormal temperature rise will cause ablation of the connector due to excessive temperature rise.

The temperature rise of the connector is affected by the following factors:

1. Contact resistance: used for conductive connection, the resistance between two contact carriers, such as pinhole-to-plug contact resistance, pinhole tail and wire crimp resistance, threaded connection copper plate and copper plate contact resistance

2. Material environment heating: When the connector is in a high temperature environment for a long time, because the materials used in the connector are engineering plastics, metal, rubber, etc., especially engineering plastics require a maximum operating temperature of 140 ℃, but when the product is used in an environment that is too high , When the connector heats up due to its own contact with internal resistance when it reaches thermal equilibrium, plus the ambient temperature is higher than the maximum working temperature allowed by the material. At this time, if the connector is in this environment for a long time and the internal temperature cannot be discharged due to the heating of the internal pinholes of the connector, the internal temperature will continue to rise, and the connector will generate a lot of heat, causing the connector to ablate It causes the vehicle to burn, which is a very serious problem. Both rubber materials and metal materials have maximum operating temperature limits, and both need to be considered during design.

3. The connection of the plate end: when bolts are used in the design, or preventive measures should be taken to prevent loosening during the supply; at the same time, when the bolt is connected, the torsion test must be carried out according to the operating specifications. In the case of screw connection of conductive parts, one of the main failure modes is that the tightening torque is not controlled in accordance with the torque requirements, resulting in abnormal temperature rise and ablation of the connection part.

4. Derating curve: Now let’s discuss the derating curve. In my understanding, the derating curve is like choosing a product. This product should be used in a specific environment. At this time, when choosing a product, According to an attribute value of this product, determine which range of products you choose. The derating curve diagram of the high-voltage connector is to provide customers with a menu, and customers choose their own suitable dishes according to their tastes according to this menu.

The derating curve is the different values corresponding to different currents under different working environment temperatures. These values are a graph obtained by the dot method. With this derating curve graph, the use conditions of the connector can be seen more intuitively.

The figure below is an illustration of the temperature rise and derating curv

Temperature rise and derating curve value

Temperature rise graph

Derating curve