Energy conservation and carbon reduction performance of small new energy vehicles based on a nudge and penalty...

The illegal recycling of new energy vehicle batteries is a major contributor to resource depletion and environmental degradation in China. This study develops a composite battery recycling algorithm by integrating nudge theory, the theory of planned behavior, and system dynamics (NT-TPB-SD), and constructs a system dynamics intervention model that incorporates both threshold-based penalties and consumers' willingness to return used batteries. A simulation-based comparison of multiple scenarios yields the following findings: (1) The combined nudge and penalty strategy reduces the illegal recycling rate by 36.8 % and decreases total lithium, nickel, and cobalt emissions by 2.3 %, 13.2 %, and 13.2 %, respectively, through a dynamic threshold breach mechanism and a positive feedback loop. (2) A significant non-linear effect is observed in the deposit gradient; within the 7.5 %-9 % vehicle cost ratio interval, Pareto optimization is achieved. (3) A "Jevons paradox" effect is identified in technology investments. Under the composite policy scenario, losses due to heavy metal pollution and ecotoxicity are reduced by 22.7 % and 18.3 %, respectively. The research provides critical insights into China's dual challenges of battery retirement and carbon peaking, offering a quantifiable decision-making basis for achieving a green closed-loop in the new energy vehicle industry.