The fast-growing electric vehicle segment is broadening China's comprehensive industry chain, including power supplies and corresponding interconnects. Between 200 and 300 China makers of the last have, in fact, added EV charging connectors and cable assemblies, and wire harnesses to their catalogs. These products account for 10 to 20 percent of output only, but the share will rise as more suppliers venture into the line in coming years.

Panawincn Wiring Harness & Cable Assembly Co. Ltd started offering wire harnesses in 2013. It plans to increase the yield ratio for EVs to between 10 and 20 percent in coming months from 5 percent, anticipating an upswing in local and overseas demand. The manufacturer is looking to realize 10 percent higher export volume from the category. It currently ships about 30 percent of yield abroad, mainly to the US, Europe and East Asia.

At Dongguan Jiafu Wire Harness Co. Ltd, products for EV use represent less than 10 percent of turnout, but may surpass 10 percent this year.

The global EV market has been surging. In 2014, shipments reached 2.2 million vehicles or up by 86 percent, according to Navigant. The boom is anticipated to carry over the next one or two years as major brands enter the segment. They include Audi, Volvo, Saab, Benz and BMW.

A similar development is happening in local car manufacture, thanks to government subsidies. By 2020, EVs will have a sales share of more than 15 percent, expanding opportunities for the upstream sectors. In interconnects, revenue growth exceeding 20 percent is already projected this year.

Mainland China's supplier pool for the line includes those with investment mainly from Taiwan and Hong Kong. Domestic businesses make up more than 70 percent of the total. The coastal provinces of Guangdong, Zhejiang and Jiangsu are the major production areas, with the first gathering over half of the companies in Shenzhen and Dongguan.

Key agenda

EVs are among the major development projects outlined in the mainland's 12th Five-Year Plan. The scheme covers battery and power supply solutions as well.

In 2011, the General Administration of Quality Supervision, Inspection and Quarantine issued the Electric Vehicle Conductive Charge Coupler (GB/T20234-2011). This stipulates key specifications, charging mode, classification, functions, performance, test methods and criteria for EV charging. The first includes 220VAC charging voltage, 16 to 32A rated current, seven contacts and IP55 rating mainly for household and public EV charging applications.

The requirements extend to securing approval such as UL, IEC 62196, SAE j1772 and RoHS.

R&D focuses on high reliability, safety

Besides the product aspects detailed in the 2011- released national standard, mainland companies ensure pull resistance, protection against misplugging and flame retardancy.

Dongguan NBC has an EV charging plug with a self-locking mechanism to prevent accidental pulling, and a safeguard against unintended contact with the terminals. The UL94V-0- and IP65-rated unit has a voltage coding pin to avoid wrong insertion. It meets IEC 62196 and SAE J1772 standards.

In wire harnesses, suppliers follow anti-EMI, and heat, cold, chemical and abrasion resistance in accordance with UL, VDE, CCC, JIS and RoHS requirements. Such products are used mainly in electric cars' storage battery power supply, lighting, signal and control systems, and switches.