Chongqing – Ouyang Minggao, academician of the Chinese Academy of Sciences and Tsinghua University professor, said that integrating electric vehicles with the power grid will transform China’s energy sector, with 2025 marking the start of vehicle-to-grid (V2G) interaction as a core part of the country’s distributed energy storage strategy.

Ouyang Minggao, an academician of the Chinese Academy of Sciences and a professor at Tsinghua University, delivered a speech at the Chongqing Energy Storage and Smart Energy Industry Development Summit. (Photo/Chen Zhan)

The Chongqing Energy Storage and Smart Energy Industry Development Summit, held recently, brought together over 100 experts, scholars, and industry leaders to discuss the future of energy systems and the deep integration of energy storage, smart energy, and urban development.

A highlight of the event was the unveiling of groundbreaking energy storage systems, including the world's first direct-cooling immersion energy storage system, developed by Qingan Energy in collaboration with Shell. 

The system can reduce auxiliary energy consumption by 60% and extend battery cycle life by 20%. With an overall energy efficiency of 89%, it maintains a temperature difference of just 1°C between the top and bottom of the battery cells. This makes it ideal for high-safety, high-efficiency, and long-lasting energy storage applications, such as integrated energy supply stations, chemical plants, office buildings, and more.

Role of V2G interaction in China's energy revolution

At the forum, Ouyang highlighted the transformative potential of V2G technology, which enables EVs to both draw power from and feed energy back into the grid, reshaping China’s energy landscape beyond breakthroughs in energy storage products.

This bidirectional energy flow helps balance energy supply and demand, making the power grid more flexible and reliable. During times of excess energy production, such as midday solar surges, EVs can absorb the surplus. During peak demand hours, when energy supply is strained, EVs can discharge their stored energy to the grid, stabilizing fluctuations. 

By 2050, China is expected to have 350 million electric vehicles on the road, generating nearly 24 billion kilowatt-hours of electricity annually—equivalent to the nation's current daily electricity consumption. Ouyang pointed out that even if only half of these vehicles are actively connected to the grid, they could form the world's largest short-term energy storage system, offering substantial support to China's growing battery storage capacity.

One of the major advantages of V2G, according to Ouyang, is its ability to provide economic benefits to EV owners. Through V2G systems, owners can store energy during off-peak hours when electricity prices are low and discharge it during peak demand when prices are higher. 

For example, a lithium iron phosphate battery in an EV can undergo 3,000 charge-discharge cycles, with the battery still retaining sufficient capacity to store energy. With the price differences between peak and off-peak electricity, EV owners could potentially earn between 75,000 and 80,000 yuan (about 10,500 and 11,200 U.S. dollars) annually through V2G systems, turning their vehicles into profitable assets.

A mobile energy storage unit powers an electric vehicle. (Photo/Qingan Energy)

Improving battery safety and longevity through V2G

Despite its significant potential, concerns about battery safety and lifespan remain barriers to the widespread adoption of V2G. However, Ouyang argued that V2G technology can help address these issues. 

Bidirectional charging, where batteries charge and discharge in a controlled manner, reduces the risks associated with traditional charging methods, such as lithium plating, which can cause battery failures or fires. Active current excitation in V2G systems enhances the detection of lithium plating, allowing for timely intervention to prevent damage.

Additionally, pulse technology used in V2G systems helps distribute lithium ions more evenly within the battery, reducing the risk of degradation and improving the battery's lifespan. This technology can also preheat batteries in cold temperatures, ensuring optimal performance and safety in various conditions. Ouyang noted that although V2G might slightly increase battery cycle degradation over time, it ultimately extends the battery’s overall life by avoiding prolonged periods of full charge.

As V2G technology continues to evolve, it holds the potential to revolutionize both the automotive and energy sectors. By enhancing grid stability and improving battery health, V2G promises to drive a more sustainable and efficient energy future for China and beyond.