Kettering University’s Advanced Power Electronics Lab continues to grow into a major research hub for the automotive electrification and renewable energy fields in the less than one year since the lab was opened.

Dr. Kevin Bai, assistant professor of Electrical and Computer Engineering, oversees the lab and has recently been conducting research for Chrysler LLC to design a high-efficiency 2.5 kilowatt electric alternator for electric vehicles. This research is unique to Kettering University and positions Kettering as a key research facility in the development of successful electric vehicle components.

The contract with Chrysler is for eight months. Bai is working with a post-doctoral student and Kettering graduate student Chen Duan on the project for three months. The research and development of the electric alternator will allow batteries in electric vehicles to be charged with both more power and more efficiency.

“In a conventional vehicle, if your 12 volt lead acid battery is dead, you’re going to need a jump to first turn the battery back on, then the battery voltage increases enough to turn the engine back on,” Bai said. “The engine drives the alternator to pump the battery again. In this case, you’re going to maintain the battery voltage by throwing the energy through the engine to the battery.”

Bai explained the difference in that process in an electric vehicle.

“In an electric vehicle, you only have the high voltage ion battery as the leading power source,” he said. “So if the 12 volt lead acid battery is dead, we are going to need the high voltage battery to convert this energy to charge the lead acid battery.”

Bai and his assistants are developing an electric alternator that would reach 95 percent efficiency. Right now, the highest efficiency those alternators reach is 92 percent and the average efficiency is in the 85-90 percent range. None currently on the market have a power of 2.5 kilowatts.

“ The first challenge is high powered, the second is high efficiency,” Bai said. “Chrysler asked us to design our electric alternator for their electric vehicles. Right now, they have a DOE project to equip 200-300 electric vehicles with this electric alternator.”

Bai said that he and Chrysler are hoping to have a patent by the end of this project on a product that can be equipped in electric vehicles.

“I believe this device will eventually give very good benefits,” Bai said. “We actually can calculate that if our efficiency in this electric alternator could rise 10 percent (to 95 percent) compared to other converters, we’re going to lift our electric vehicles’ miles per gallon 1 percent. That will save a lot of energy and make the overall vehicle more efficient.”

This project is another in a string of electrical vehicle research conducted in the Power Electronics Lab.

“This lab so far is pretty successful,” Bai said. “We’ve been able to get funding of roughly $750,000 in the past year. All of this is coming from vehicle electrification. We’ve done work for Tenneco, Magna, Chrysler and several other electric suppliers. Right now, the lab is getting the most attention from the vehicle electrification domain. But I’m always trying to diversify our research, not only in vehicle electrification but also in renewable energy, battery research. The battery research is not just limited to electric vehicles – think of your cell phone, wind energy, this stuff all needs a battery.”

Because of this heavy demand for battery research, as well as a growing need for engineers who have some expertise with how batteries work currently needed in industry, Bai has developed a Battery Management System course, a 500 level class for senior and grad level students. There are 20 students currently enrolled and Bai’s goal with the course is to help students understand how a battery works and how to use and charge it properly.

“Right now, vehicle electrification and renewable energy are very hot, very popular, which needs the application of a battery as an energy storage component,” Bai said. “The problem with this process is a lot of engineers don’t know how to use the battery appropriately, so all of our knowledge is based on a data sheet given by manufacturers. Our application engineers can’t solve some of these problems – for example, the battery is overcharged, the battery is undercharged, sometimes we use the same charger to charge different types of batteries that need different chargers thinking it will be fine.”

“In this course, I will go from the very basics, battery chemistry, to help students understand what’s really inside the battery,” Bai continued. “In this case, students will know why a battery is able to store energy, how it is stored, what’s the difference between lead acid, nickel and Li-ion batteries and why eventually people chose Li-ion instead of lead acid or nickel in electric vehicles.”

The course also contains elements from many different fields of study.

“This will be another very inter-disciplinary course at Kettering – it involves chemistry, physics, mechanical engineering, digital signal processing,” Bai said. “After this experience, students shouldn’t have any problem merging themselves into the present automotive industry.”

Bai focuses on battery chemistry and eventually moves on to all other aspects of the battery – how to estimate the charge of a battery, how to estimate the health of the battery, how to design a battery charger, how to balance battery voltage when charging and discharging and other key battery related functions.

“At the end, we integrate all these functionalities together for the student to build a prototype battery management system to provide a state of the charge estimation and state of health estimation,” he said. “I will also introduce some future topology that could be used in the future of the industry. The course is very challenging and application oriented.”

Although challenging, the payoff is also potentially rewarding as engineers with knowledge and expertise in batteries are in demand as companies seek to advance battery technology.

“I had four senior students doing independent study in the last several term, developing a battery equalizer and learned some measurements for state of health/charge,” Bai said. “At the end they were all hired by automotive companies due to their battery expertise.”

Read more about the Power Electronics Lab.