Figure 5
The horizontal axis of the graph is labeled “Relevance degree (Centrality).” The vertical axis of the graph is labeled “Development degree (Density).” A horizontal dashed line is drawn parallel to the horizontal axis at the midpoint of the vertical axis. Similarly, a vertical dashed line is drawn parallel to the vertical axis at the midpoint of the horizontal axis value. These two lines intersect at the point and divide the graph into four quadrants. The bottom-left quadrant is labeled “Emerging or Declining Themes.” The top-left quadrant is labeled “Niche Themes.” The top-right quadrant is labeled “Motor Themes.” The bottom-right quadrant is labeled “Basic Themes.” In the “Niche Themes” quadrant, there are two circular nodes. The first node is at the top center, labeled “charge scheduling,” which connects to a text box that reads “Charge scheduling 4.” The second circular node is on the top right inside the quadrant labeled “battery electric vehicle electric mobility,” connected to a text box that reads “Battery electric vehicle 10,” “Electric mobility 8,” “Sustainable transportation 7,” “C O 2 emissions 4,” “Plug-in electric vehicles 4,” “Public transport 4,” “Sustainable development 4,” and “Sustainable transport 4.” In the “Motor Themes” quadrant, there are two circular nodes. The first node is at the bottom center labeled “charging stations energy management strategy,” which connects to a text box that reads “Charging stations 34,” “Energy management strategy 7,” “Electric buses 5,” “Fast charging 5,” “Battery 4,” “Charging 4,” “Incentives 4,” “Lagrangian relaxation 4,” and “Range anxiety 4.” The second circular node on the right side is labeled “E V sustainability,” which connects to a text box that reads “E V 222,” “Sustainability 13,” “Vehicle-to-grid 12,” “Sustainable mobility 9,” “Smart charging 8,” “Transportation 8,” “Renewable energy 7,” “E-mobility 6,” “Smart grid 6,” “Demand response 5,” “E V charging 5,” “Policy 5,” “Battery electric vehicles 4,” “Carbon footprint 4,” “Electric vehicle charging station 4,” “Fast charging station 4,” “India 4,” “Photovoltaic 4,” “Solar energy 4,” “System dynamics 4,” and “Uncertainty 4.” In the “Basic Themes” quadrant, there is only one circular node on the bottom left labeled “electric vehicle charging,” connected to a text box that reads “Electric vehicle charging 10.” In the “Emerging or Declining Themes” quadrant, there are two nodes. The first node on the top center is labeled “electromobility,” connected to a text box that reads “Electromobility 5.” The second node in the center of the quadrant is labeled “electric vehicles (E Vs) barriers,” connected to a text box that reads “Electric vehicles (E Vs) 7” and “Barriers 5.” On the horizontal dashed line between the “Basic Themes” and “Motor Themes” quadrants, a circular node is present labeled “charging infrastructure optimization,” connected to a text box that reads “Charging infrastructure 27,” “Optimization 10,” “Electric bus 7,” “Electric vehicle routing problem 5,” “Battery swapping 4,” “Mixed-integer linear programming 4,” and “Multi-objective optimization 4.” On the vertical dashed line between the “Basic Themes” and “Emerging or Declining Themes” quadrants, a circular node is present labeled “charging scheduling blockchain,” connected to a text box that reads “Charging scheduling 7” and “Blockchain 5.” In the bottom right corner, a blue shield-shaped logo contains the text “Bibliometrix.”Thematic map. Source: Authors’ composition (bibliometrix R studio)