1. High Voltage Interlock
High Voltage Interlock (HVIL) refers to a safety design method used to monitor the integrity and continuity of high-voltage circuits through low-voltage signals.
Additionally, the HVIL function is integrated into the high-voltage connector. It is essential to ensure that the HVIL circuit is disconnected before connecting or disconnecting the high-voltage connector, with a necessary time delay maintained in between.
The time delay between the HVIL and the electrical connection sequence of the connector can be determined based on specific circumstances, generally around 150 milliseconds. The purpose is to avoid system feedback delays and prevent instantaneous high voltage during power disconnection from damaging the product or the operator.
2. Mechanical Performance
2.1 Interface and Frame Dimensions
Both the supplier and the buyer need to clarify the interface dimensions. The design of the high-voltage connector must ensure that the phases cannot be confused in any way (e.g., by adding features such as mechanical keying, color coding, or key identification). Additionally, other product information, such as the cable exit method, should be specified.
2.2 Mechanical Lifespan
In the power transmission system of on-board high-power and low-power modules, the mechanical lifespan of high-voltage connectors is typically not high, usually between 50 and 100 cycles.
In charging interface applications, the product needs to have a mechanical lifespan of 10,000 cycles, which poses a significant challenge to the overall performance of the high-voltage connector, especially the conductive terminals.
2.3 Insertion Force
The insertion force for high-voltage connector products is typically required to be no more than 100N. If it exceeds 100N, it is necessary to add appropriate auxiliary devices, such as slide rails or lever mechanisms.
The insertion force of the conductive terminal is a major component of the overall product insertion force. Low-insertion-force conductive terminals help facilitate easier and more feasible insertion operations of the connector product.
It is well known that contact resistance decreases as normal force increases. This presents a significant challenge for conductive terminals, as they need to balance low normal force and insertion force with low contact resistance.
2.4 Retention Force
The retention of the high-voltage connection and the retention of the plastic components with the conductive terminals are important considerations. Many high-voltage connectors in the industry lack quantified retention force for the latching mechanism, and there are issues such as torque deficiencies in the latch, leaving room for significant optimization.
2.5 Secondary Lock
High-voltage connectors need to have a secondary locking mechanism. The secondary locking mechanism requires a certain unlocking force (usually no more than 40N). The main purpose is to prevent the high-voltage connector from accidentally opening due to external forces during transportation and handling.
2.6 Anti-Mismating and Identification
High-voltage connectors are typically marked in orange. These connectors must have mechanical anti-mismating features, meaning they meet a certain force value for incorrect plug and socket insertion (anti-mismating force > 3 times the insertion force, typically at least 80N), ensuring that the terminals are not affected by any form of damage.
2.7 Vibration and Shock Performance
High-voltage connectors must be designed to withstand certain mechanical loads. Generally, they need to meet vibration level 3.
2.8 Crimp Strength
The terminals and cables of high-voltage connectors need to achieve a certain crimp strength to maintain stable crimp resistance over long periods under temperature cycling conditions. This is also to prevent crimping from loosening due to vibration, swinging, or other inertial forces affecting the micro terminals.
3. Environmental Performance
3.1 Touch Protection
In both the mated and unmated states of high-voltage connectors, they must meet the protection requirements of IPXXB and IPXXD to prevent operators from accidentally coming into contact with live parts and getting injured.
3.2 Sealing Protection
When high-voltage connectors are in the mated state, they typically need to meet the sealing requirements of IP6K9K and IPX7 (charging interfaces, whether in the mated or unmated state, generally need to meet the sealing requirements of IP54/IP55).
3.3 Salt Spray Resistance
When high-voltage connectors are in the mated state, they typically need to meet the corrosion requirements of IEC 60068-2-52 or GB/T 2423.18 for alternating salt spray tests, severe corrosion, etc.
This article is republished from the WeChat public account: Automotive Research Institute Auto.