Nav: Home

UToledo engineer creates solution to cheaper, longer lasting battery packs

March 06, 2018

An electrical engineer at The University of Toledo, who nearly died as a girl in Africa because of a hospital's lack of power, has developed a new energy storage solution to make battery packs in electric vehicles, satellites, planes and grid stations last longer and cost less.

The new technology called a bilevel equalizer is the first hybrid that combines the high performance of an active equalizer with the low cost of the passive equalizer.

"It's a game changer because we solved the weak cell issue in lithium ion battery storage for packs with hundreds of cells," said Dr. Ngalula Mubenga, assistant professor of electrical engineering technology at UT. "Whenever we are talking about batteries, we are talking about cells connected in a series. Over time, the battery is not balanced and limited by the weakest cell in the battery."

Before the bilevel equalizer, battery makers and automotive manufacturers balanced the cell voltages in a large battery pack using either a passive circuit, which loses more energy, or an active circuit, which is 10 times more expensive.

"In spite of their significant losses, passive equalizers are used in most applications because they are relatively simple and low cost," Mubenga said.

In Mubenga's new technology, the cells are grouped into sections. Each cell within the section is balanced by a passive equalizer, while the entire section is balanced by an active equalizer.

"If there are 120 cells in a battery, divide the cells into 10 groups of 12," Mubenga said. "Then you only need nine active equalizer units and 120 passive equalizer units using the bilevel equalizer. With current active equalizers, manufacturers would have to use 120 active equalizers. For manufacturers that can't afford to use only active equalizers, the bilevel equalizer is the solution to the problem."

Experiments have shown that the bilevel equalizer increases the discharge capacity of lithium ion batteries by about 30 percent, and the pack lasts longer because the cells are balanced.

"Instead of an electric vehicle's battery lasting only four years, it would last much longer," Mubenga said.

Mubenga worked on the project with Dr. Tom Stuart, professor emeritus in the UT Department of Electrical Engineering and Computer Science, who had the idea for the bilevel equalizer.

Their team is licensing the hybrid equalizer and retrofit kit to manufacturers. The research was recently published in Batteries, an international journal. Project funding was provided by the Ohio I-Corps program and Ohio Third Frontier program.

Mubenga plans to present their new, patented technology at 2 p.m. Wednesday, March 7 at the Advanced Design and Manufacturing Expo at the Huntington Convention Center of Cleveland in a session titled "Lowering the Cost of Energy Storage for E/HV and Grid Applications Using a Bilevel Equalizer for Large Li-Ion Batteries."

Mubenga understands the life-changing power of electricity. When she was 17 years old in her native country of the Democratic Republic of Congo in Africa, she waited three days for surgery after her appendix burst because there was no power at the hospital.

"I was living in a small town called Kikwit, far away from the big and beautiful capital city of Kinshasa," Mubenga said. "I was very sick, doctors needed to do surgery, but they couldn't find any gas to turn on the power generator. For three days, my life depended on electricity. I was praying. I could not eat. And decided if I made it alive, I would work to find a solution so people wouldn't die because of lack of electricity."

The hospital found fuel to power the generator, doctors did the surgery and Mubenga survived.

She started studying renewable energy at the UT College of Engineering in 2000 and earned a bachelor's degree, master's degree and PhD in electrical engineering. After earning her professional engineer license in Ohio, she went on to found her company called the SMIN Power Group, which develops and installs solar power systems in communities throughout the Democratic Republic of Congo.

"My passion is deep," Mubenga said. "In places like that small town of Kikwit, if you have solar power, you can have electricity and save lives."

Another factor fueling Mubenga's research motivation is a connection between her native country and lithium ion batteries.

"Most of the minerals for today's electronics are mined in the Democratic Republic of the Congo," Mubenga said. "The Democratic Republic of the Congo is a leading producer of cobalt, copper, gold, diamond, tantalum and tin in the world. Indeed, the Democratic Republic of the Congo contains about 50 percent of the world's reserve of cobalt, a mineral used to make lithium ion batteries."
-end-


University of Toledo

Related Engineering Articles:

Engineering a new cancer detection tool
E. coli may have potentially harmful effects but scientists in Australia have discovered this bacterium produces a toxin which binds to an unusual sugar that is part of carbohydrate structures present on cells not usually produced by healthy cells.
Engineering heart valves for the many
The Wyss Institute for Biologically Inspired Engineering and the University of Zurich announced today a cross-institutional team effort to generate a functional heart valve replacement with the capacity for repair, regeneration, and growth.
Geosciences-inspired engineering
The Mackenzie Dike Swarm and the roughly 120 other known giant dike swarms located across the planet may also provide useful information about efficient extraction of oil and natural gas in today's modern world.
Engineering success
Academically strong, low-income would-be engineers get the boost they need to complete their undergraduate degrees.
HKU Engineering Professor Ron Hui named a Fellow by the UK Royal Academy of Engineering
Professor Ron Hui, Chair Professor of Power Electronics and Philip Wong Wilson Wong Professor of Electrical Engineering at the University of Hong Kong, has been named a Fellow by the Royal Academy of Engineering, UK, one of the most prestigious national academies.
Engineering a better biofuel
The often-maligned E. coli bacteria has powerhouse potential: in the lab, it has the ability to crank out fuels, pharmaceuticals and other useful products at a rapid rate.
Pascali honored for contributions to engineering education
Raresh Pascali, instructional associate professor in the Mechanical Engineering Technology Program at the University of Houston, has been named the 2016 recipient of the Ross Kastor Educator Award.
Scaling up tissue engineering
A team at the Wyss Institute for Biologically Inspired Engineering at Harvard University and the Harvard John A.
Engineering material magic
University of Utah engineers have discovered a new kind of 2-D semiconducting material for electronics that opens the door for much speedier computers and smartphones that also consume a lot less power.
Engineering academic elected a Fellow of the IEEE
A University of Bristol academic has been elected a Fellow of the world's largest and most prestigious professional association for the advancement of technology.

Related Engineering Reading:

Mechanical Engineering Reference Manual for the PE Exam, 13th Ed
by Michael R. Lindeburg PE (Author)

Engineering: An Illustrated History from Ancient Craft to Modern Technology (100 Ponderables)
by Tom Jackson (Editor) (Author), Tom Jackson (Editor)

Basic Machines and How They Work
by Naval Education And Training Program (Author)

Materials Science and Engineering: An Introduction
by William D. Callister Jr. (Author), David G. Rethwisch (Author)

The Engineering Book: From the Catapult to the Curiosity Rover, 250 Milestones in the History of Engineering (Sterling Milestones)
by Marshall Brain (Author)

Shigley's Mechanical Engineering Design (McGraw-Hill Series in Mechanical Engineering)
by Richard G Budynas (Author), Keith J Nisbett (Author)

Mathematical Methods for Physics and Engineering: A Comprehensive Guide
by K. F. Riley (Author), M. P. Hobson (Author), S. J. Bence (Author)

Refrigeration and Air Conditioning Technology
by John Tomczyk (Author), Eugene Silberstein (Author), Bill Whitman (Author), Bill Johnson (Author)

SE Structural Engineering Reference Manual
by Alan Williams PhD SE FICE C Eng (Author)

Site Reliability Engineering: How Google Runs Production Systems
by Niall Richard Murphy (Author), Betsy Beyer (Author), Chris Jones (Author), Jennifer Petoff (Author)

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Circular
We're told if the economy is growing, and if we keep producing, that's a good thing. But at what cost? This hour, TED speakers explore circular systems that regenerate and re-use what we already have. Guests include economist Kate Raworth, environmental activist Tristram Stuart, landscape architect Kate Orff, entrepreneur David Katz, and graphic designer Jessi Arrington.
Now Playing: Science for the People

#504 The Art of Logic
How can mathematics help us have better arguments? This week we spend the hour with "The Art of Logic in an Illogical World" author, mathematician Eugenia Cheng, as she makes her case that the logic of mathematics can combine with emotional resonance to allow us to have better debates and arguments. Along the way we learn a lot about rigorous logic using arguments you're probably having every day, while also learning a lot about our own underlying beliefs and assumptions.