Study at RWTH suggests bidirectional charging poses minimal battery strain
A new study reveals that Vehicle-to-Grid (V2G) bidirectional charging has a minimal to moderate impact on the lifespan of electric vehicle (EV) batteries, offering a balance between battery aging and significant grid benefits.
In contrast to V2G, intelligent unidirectional charging (V1G) and direct charging have different effects on battery health and grid management.
V2G, which allows the EV battery to both charge from and discharge to the grid, theoretically increases the number of charge-discharge cycles, potentially accelerating battery aging. However, recent research indicates that V2G causes about a 18% battery capacity degradation over ten years, a modest impact that is comparable or slightly worse than V1G.
V2G offers an additional advantage: the potential for users to generate revenue by providing grid services. This is supported by a 2025 study that highlights the potential for drivers to earn financial value (up to €600/year) using bidirectional charging [3].
Intelligent charging (V1G), on the other hand, is a unidirectional, often smart charging method that minimizes grid strain by optimizing the timing and rate of charging but does not support discharging energy back to the grid. This method can reduce battery stress by avoiding aggressive charging patterns but lacks the ability to offer additional grid services or revenue to the user.
Direct charging, or conventional, uncontrolled charging, tends to have the highest potential for battery degradation due to uncontrolled charging sessions often coinciding with peak power demand and faster charging cycles.
Here's a comparison of the three charging scenarios:
| Charging Scenario | Impact on Battery Lifespan | Additional Benefits | |----------------------------|-----------------------------------|------------------------------------------------| | Vehicle-to-Grid (V2G) | Minor to modest degradation (~18% over 10 years) due to more cycles[2][3] | Can generate revenue for users; supports grid stability by discharging energy back[3][4] | | Intelligent Charging (V1G) | Lower degradation by controlling charging timing and rate, avoids peak demand spikes[5] | Reduces electricity costs; manages grid load but no energy export capability[5] | | Direct Charging | Highest potential degradation due to uncontrolled charging patterns | No grid or economic benefits |
The study also suggests that V2G operation is particularly battery-friendly when battery management systems (BMS) and power traders work together. This collaboration can better communicate and consider battery limits in trading, ultimately minimizing battery stress [4].
The study aims to contribute to better utilization of V2G advantages in the future. By understanding the impact of these charging scenarios on battery lifespan, users can make informed decisions about charging their EVs and maximizing their battery's lifespan while also taking advantage of grid benefits.
References:
[1] The Mobility House and RWTH Aachen University Joint Study on Bidirectional Charging [2] P3 Whitepaper on the State of Health of Batteries [3] 2025 Study Confirming V2G's Battery Aging Effect is Nearly Harmless [4] Whitepaper on V2G Operation and Battery Management Systems [5] Information on Intelligent Charging (V1G)
Science reveals that while Vehicle-to-Grid (V2G) can potentially accelerate battery aging due to increased charge-discharge cycles, it causes only minimal to modest degradation, amounting to approximately 18% over ten years. This is, in fact, comparable to the degradation rate associated with intelligent unidirectional charging (V1G). On the other hand, finance plays a role as V2G allows users to generate revenue by providing grid services, with the potential for drivers to earn up to €600/year using bidirectional charging, as suggested by a 2025 study.
