Energy storage functions and technological developments of vehicle-to-everything enabled electric vehicle chargers: Converter designs, control strategies, services, and market readiness

Vehicle-to-Everything (V2X)–enabled chargers transform electric vehicles into flexible distributed energy storage units by enabling bidirectional energy exchange during off-peak periods or surplus renewable generation and supplying energy to the grid, homes, local loads, or other vehicles through vehicle-to-grid, vehicle-to-home, vehicle-to-load, and vehicle-to-vehicle functionalities. This capability positions the V2X charger as a critical interface for intelligent, resilient, and grid-interactive energy systems. This review comprehensively examines the technological developments enabling these functions, focusing on bidirectional AC–DC and isolated and non-isolated DC–DC converter topologies that constitute the core of V2X chargers. Their operating principles, structural characteristics, and performance trade-offs are analyzed to clarify how topology selection influences efficiency, harmonic performance, voltage stress, power density, galvanic isolation, and soft-switching robustness under wide operating conditions. Advanced control strategies for grid-following and grid-forming operation are systematically reviewed under grid-connected and islanded scenarios, incorporating stability analysis, impedance interaction, communication latency, zero-voltage-switching boundary limitations, and weak-grid resilience, with and without solar integration. Beyond converter-level assessment, V2X services are synthesized using a state-of-charge–based supervisory framework governing coordinated mode transitions, user participation settings, and battery protection constraints. Laboratory prototypes, pilot-scale demonstrations, and commercial products are comparatively benchmarked to identify disparities in efficiency, certification readiness, interoperability, photovoltaic and home energy management system compatibility, environmental robustness, grid-code compliance, deployment scalability, lifecycle cost considerations, safety certification processes, and long-term operational reliability. Finally, a SWOT-based assessment outlines ideal characteristics and strategic development pathways toward scalable, secure, interoperable, and market-ready next-generation V2X chargers. • Reviews bidirectional converter designs for V2X-enabled energy storage chargers • Summarizes control strategies for efficient, stable, and grid-interactive operation • Compares academic prototypes with commercially deployed V2X charger systems • Evaluates V2G, V2H, V2L, and V2V services and their practical feasibility • Identifies key design features and gaps via SWOT analysis of V2X chargers