Identifying Core Technology Structure of Electric Vehicle Industry through Patent Co-citation Information

Electric vehicles (EV), which have various energy sources and have quite low emission, have come to be one of strategic emerging industries. This article aims to identify its core technology structure so as to understand the recent progress of EV technology innovation. This has important implication for policy - making at governmental level and strategic decision-making at firm level. The authors use a method of patent co-citation information to identify the core technologies of EV industry. Five core technology groups have been shaped up as driving system arrangement & control, energy management & control, battery management, transmission system control, and motor design & control. Core technology assignees are decentralized as the most productive eight assignees possess 55.7% of core patents. None Chinese assignee is listed in these EV core patents. (C) 2011 Published by Elsevier Ltd. Selection and peer-review under responsibility of RIUDS