Spring finger contacts: features and applications

Spring finger contacts are a relatively new type of electrical connection product. They offer a simple structure, easy installation, high current-carrying capacity and low cost, and are widely used in high-voltage switchgear, high-speed rail, petroleum exploration and testing equipment, and new-energy vehicles.

Key product features

High current-carrying capacity; a simple structure with multi-point contact and minimal heat build-up; and resistance to electrical sparking on impact, with an automatic arc-extinguishing function.

Because each coil works independently, the contact tolerates large-area contact tolerance and compensates for surface irregularities, which effectively prevents resistance drift. It maintains good performance under shock, vibration and harsh environmental conditions.

Operating temperature: -25 °C to 105 °C. Hardness: HV ≥ 370.

Development and manufacturing

SISE independently develops and produces spring fingers. A dedicated forming process and multiple precision heat-treatment steps ensure the accuracy and performance of the product. Dongguan SISE (Spring-in-Spring) Electronics Co., Ltd. was founded in October 2011 to design, test and manufacture elastic conductive electronic components, and moved to Chang'an Town, Dongguan in May 2018. The facility includes a CNC lathe workshop, a spring finger workshop, an assembly workshop and a laboratory.

Product range and performance

Responding to the connector industry's demand for higher current ratings, SISE developed the two-way coil spring finger (SiS®) and the single-turn spring finger. These form multiple columnar deformation contact points, up to more than 300, with a service life exceeding 100,000 cycles. Current density and temperature rise are close to those of the connecting cable, and the insertion force is about 10 N.

Applications

The product family covers board-to-board and board-to-wire PCB connectors, cylindrical quick-plug self-locking connectors (plastic and metal shells), male and female connectors with balanced loading, electric-vehicle chargers, and series connectors for high-voltage power battery packs. These are used in advanced high-current energy collection, energy storage and electrical equipment such as electric vehicles, charging stations, wind generators, power supplies, high-speed rail and heavy trucks. The company holds a number of national patents, and its products have passed international standard testing.