PhD profile: Yifeng Li

An interest in battery control systems led Yifeng Li to the School of Chemical Engineering at UNSW.

As a PhD student in the Process Control Research Group, Yifeng is developing a control system for Vanadium Redox-cell batteries, a technology that was created by UNSW Emeritus Professor Maria Skyllas-Kazacos in the 1980s.Yifeng Li in the Process Control Lab, School of Chemical Engineering

“It’s basically an energy storage system,” says Yifeng, who is currently in the third year of his PhD under the supervision of Professor Jie Bao and Emeritus Professor Skyllas-Kazacos.

“It’s a particularly good piece of technology in power quality control, and energy peak shaving and load levelling applications.”

Yifeng and his research colleagues are developing the battery for use in a residential context, such as unit blocks, where a storage bank can be set up somewhere in the building.  The battery can store electricity during off-peak periods when energy prices are low, and can then be used to power the building at peak times.

As well as saving money for electricity account holders by protecting them from peak period price fluctuations, the battery also ensures energy quality by taking pressure off the electricity grid. Technologies like this are key to combatting climate change, reducing reliance on fossil fuels and limiting greenhouse gas emissions by providing energy storage and distribution alternatives.

We can actually balance the electricity supply and demand. The battery acts like a buffer, so we can store the energy when there’s excess, and supply the energy when there’s a shortage.

Yifeng Li

“If everyone on a hot summer day turns on their air conditioning, if the load is too much, everything shuts down and whole areas can black out,” Yifeng says.    

“We can actually balance the electricity supply and demand. The battery acts like a buffer, so we can store the energy when there’s excess, and supply the energy when there’s a shortage.”

Yifeng’s PhD is largely focused on developing a control system for the battery. His research has been divided into three key stages.

“Firstly, we’ve developed a detailed dynamic model of the process, which captures all the crucial behaviours of the battery,” he says.

“The second aspect of my research is to monitor its performance – its temperature, its state of charge and the current and voltage the battery provides.

“The third aspect is the development of a control and management system for the battery.”

Residential Micro-Grid with distributed PV generation, battery energy storage system and load

For Yifeng, the PhD has delivered a wealth of skills, gleaned from working with supervisors who are internationally acclaimed in the field of next generation technologies. Professor Bao is an expert in control systems and theory, while Emeritus Professor Skyllas-Kazacos is the leading authority on Vanadium Redox-cell batteries. The research team also includes a postdoctoral fellow with expertise in power systems and power quality controls.

“In terms of research or doing your PhD, it’s really about teamwork – you cannot just finish the project on your own. Every development here is an achievement by the whole team,” he says.  

“I think UNSW is a great university for this technology and engineering development. We have leading edge technology, we have all the fantastic facilities, so we can build up our research and do a lot of research techniques that we might not be able to do elsewhere.”

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