Hybrid and Electric Vehicles and Powertrains

Hybrid and electric vehicles encompass a spectrum of architectures that combine or replace conventional internal‐combustion engines with one or more electric machines and energy‐storage devices. In battery electric vehicles the sole source of tractive power is a high‐voltage battery pack that drives one or more electric motors through power‐electronic inverters. Hybrid powertrains range from mild‐hybrid systems, in which a small electric machine provides start–stop functionality, torque assist and recuperation of braking energy, to full hybrids and plug‐in hybrids that permit electric‐only operation over urban distances. Architectures include series hybrids, in which the engine drives a generator and the wheels are driven exclusively by electric motors; parallel hybrids, in which mechanical and electrical torques combine at a transmission; and power‐split hybrids that use planetary gearsets to apportion engine output between mechanical drive and electrical conversion. Across all configurations, advances in battery chemistry, high‐efficiency power electronics and machine design have steadily increased energy density, reduced mass and improved thermal robustness. Digital‐twin models, model‐predictive and reinforcement‐learning controllers enhance real‐time energy management to balance minimising fuel use, extending battery life and meeting performance demands. Integration with renewable charging infrastructure and vehicle‐to‐grid services further reinforces the role of these vehicles in decarbonising transport and stabilising electrical networks globally.

Research from Nature Portfolio

Recent work has introduced a coordinated drive‐mode switching strategy for distributed‐drive electric vehicles featuring combined battery and supercapacitor energy storage. By defining stair‐based transition functions matched to machine and storage dynamics, this approach dramatically reduces DC‐bus fluctuations and suppresses torque ripples during power‐source commutation. Another study has quantified the coupling between acceleration profile, energy consumption per kilometre and battery capacity loss, demonstrating that more aggressive acceleration patterns incur disproportionately greater capacity fade. Emerging research also proposes an energy‐management system for battery–supercapacitor drivetrains that employs a Slap‐Swarm optimisation algorithm alongside differential flatness control. This hybrid optimisation scheme guarantees DC‐bus stabilisation, minimises voltage ripple and mitigates current harmonics, thereby enhancing battery lifetime under transient demands.

Hybrid and Electric Vehicles and Powertrains publication trend

The graph below shows the total number of articles in hybrid and electric vehicles and powertrains across all publications each year (not limited to Nature Index journals).

Technical terms

Power‐split hybrid: A drivetrain in which a planetary gearset divides engine power between mechanical drive and an electrical generator, enabling flexible operating modes.

Regenerative braking: A method of energy recovery that uses the electric machine as a generator during deceleration, converting kinetic energy back into electrical energy.

Slap‐Swarm optimisation: A bio‐inspired algorithm combining Slap (Social Learning and Partitioning) and Swarm (particle‐swarm) techniques for rapid parameter tuning in control systems.

Differential flatness control: A model‐based strategy that exploits flat outputs to simplify trajectory planning and tracking under dynamic constraints.

Stair‐based transition function: A piecewise function defining smooth intermediate steps for switching between drive modes to match transient dynamics.

Reinforcement learning (RL): A machine‐learning approach in which an agent iteratively refines control policies by maximising cumulative rewards under environmental interactions.

Model predictive control (MPC): An optimisation framework that uses a dynamic model to predict future states and compute control actions under constraints.

References

1. New coordinated drive mode switching strategy for distributed drive electric vehicles with energy storage system. Scientific Reports (2024).
2. Research on the interaction between energy consumption and power battery life during electric vehicle acceleration. Scientific Reports (2024).
3. Energy management of electric vehicle using a new strategy based on slap swarm optimization and differential flatness control. Scientific Reports (2024).
4. Q-learning based control for energy management of series-parallel hybrid vehicles with balanced fuel consumption and battery life. Energy and AI (2023).
5. Energy Management Strategies for Hybrid Electric Vehicles: Review, Classification, Comparison, and Outlook. Energies (2020).
6. Fuel Cell Electric Vehicles—A Brief Review of Current Topologies and Energy Management Strategies. Energies (2021).
7. An Overview of Electric and Hybrid Vehicle Technology.