Tracing evolutionary trajectory of charging technologies in electric vehicles: patent citation network analysis

The development of electric vehicles (EVs) has been expanding rapidly in recent years to meet the demand of energy conservation and environmental protection. However, despite the promotion of EV, consumers are reluctant to buy EV because of issues such as charging anxiety and charging safety. For companies to break into the fierce competitiveness of the EV industry, it is imperative that those companies understand the evolutionary trajectory of EV technology to help them choose the right technology development path, and then focus on R&D objectives and improve R&D efficiency. This study proposes a patent-based framework to understand key characteristics, evolutionary trajectories and research development of EV charging technology. The results show that key technological developments in EV charging are concentrated on circuit arrangement, battery, safety device and charging station technologies. According to our co-opetition situation analysis, giant institutions do not cooperate closely with each other but compete mainly in the fields of electric traction, circuit arrangements, EV system control and charging stations. The findings not only contribute to monitoring the developmental trends and co-opetition situations in the EV charging field, but also provide managemental implications for policymakers in governments and managers in enterprises on the how to focus on research and development for EV based on the evolutionary trajectory from the patent analysis.