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The lead-free and beryllium- free hyperboloid contact is set in a body made from high conductivity copper alloy (approximately 90% IACS or International Annealed Copper Standard) to deliver superior conductivity performance compared to other CCS DC+ and DC- sockets, which are manufactured with brass (approximately 25% IACS). Further, unlike other socket technologies which are stamped to a hyperboloid geometry with high electrical contact resistance, the Hypertac Green Connect socket has wires in the hyperboloid cage made from high conductivity novel material (approximately 55% IACS). Testing a new connector solution To ensure performance, designers exposed the Hyper- tac Green Connect to a series of intense performance, safety, and exposure tests. Mating cycle test. A test bench was set up, where the pin and socket pairs were mated and unmated up to 60,000 cycles, keeping all other variables the same. At the end of 100; 500; 1,000; 2,000; 5,000; 10,000; 15,000; 20,000; and then increments of 10,000 cycles, the machine was stopped to carry out certain critical measurements on contact resistance, temperature rise, and energy transmitted at 500 A. Contact resistance test. The test setup involved ap- plying 100 Amps through the contacts and then mea- suring the voltage drop across the pin and sockets. The objective of this test was to observe the behavior of the contact resistance across the product’s lifecycle (up to 60,000 cycles). Temperature rise test. In this test, 1.5 m of 70 sq mm cable was terminated on each of the contacts, and 250 A was applied through each of them. This current was applied until the samples under tests reached thermal stability. Temperature rise was then measured through the difference between the temperature reached by the contacts and the ambient temperature. The objective of this test was to observe the temperature rise and
Figure 1 - Electrical constriction resistance1 2
Since the conducting paths are constricted through the a-spots, the electrical resistance increases. This increase is called constriction resistance. Further, contaminant films on the mating surfaces increase the resistance of a-spots. The total resistance due to constriction and contaminant films is known as contact resistance. The constriction current produces Joule heating and increas- es local temperature, which further exacerbates with thousands of mating cycles. The higher the electrical contact resistance, the higher the level of contact over- heating and unwanted power loss. Case Study: A contact solution Interconnect suppliers have experimented with various design strategies to mitigate these challenges. One solution, Smiths Interconnect’s Hypertac Green Connect socket, designed to IEC2196 and SAE J1772 standards, can deliver up to 90% more energy at 500 A boost cur- rent mode. This represents a significant improvement over existing technologies, allowing faster, more effi - cient charging with less energy loss. Designed for ultrafast high-power charging, the Hypertac Green Connect excels in boost current mode, providing longer periods where current exceeds the rated continuous current. The contact is built to endure up to 60,000 mating cycles — a lifespan far exceeding most alternative products — ensuring that CPOs can rely on the same connector for extended periods without incurring additional service cost and performance degradation.
1 White paper of Charging Interface Initiative e.V. – Introduction of boost current for EV DC-Charging 2025-02-04 2 Holm, R., Electrical Contacts, Springer
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