Battery science earns Nobel Prize and speeds bus electrification

by Peter Corbett

It’s taken decades to reach this point, but lithium-ion battery technology is poised to power growing fleets of electric buses and motorcoaches.

As costs go down for producing lithium-ion battery packs, zero-tailpipe-emission electric buses are getting closer to cost parity with buses powered by internal combustion engines.

Battery technology is advancing, too, and with demand increasing for electric vehicle (EV) buses, the economy of scale for production will continue to lower the overall cost of ownership, said Dustin Grace, vice president of technology for Proterra Inc., which designs and manufactures EV buses in California and South Carolina.

“Based on the merits of the cost to run, we’re already past that crossover point,” Grace said of EV buses competing on cost to operate vs. diesel buses. “There’s the inconvenience of switching, which is what we’re working on to overcome.”

Costly charging systems and an adequate electrical grid for recharging bus fleets are among the challenges for the EV bus industry. The vehicle range and fire safety of lithium-ion batteries are other key concerns.

Still, the overall trajectory of the technology is inspiring optimism for cleaner, quieter EV buses that have lower energy costs and generally require less maintenance than buses powered by internal combustion engines.

In a recent report, Bloomberg New Energy Finance forecasts annual sales of EV buses for the United States, Europe and China will increase from less than half of all bus sales in 2019 to 70 percent by 2030.

To understand growth in the EV bus market, it’s worth looking at advances in battery technology that made it possible. That work goes back more than 40 years but has accelerated this century.

In early October, the Royal Swedish Academy of Sciences in Stockholm awarded the Nobel Prize in Chemistry to three scientists—M. Stanley Whittingham, John Goodenough and Akira Yoshino—for their work in developing lithium-ion batteries.

Whittingham started work on the foundations of lithium-ion batteries in the 1970s during the U.S. energy crisis. Goodenough advanced the research and Yoshino created the first commercially viable lithium-ion battery in 1985, according to the Royal Swedish Academy.

In the 1990s, lightweight and rechargeable lithium-ion batteries were put to use in a wide range of electronics, including smart phones, laptop computers and eventually electric vehicles.

“The battery has enabled development of cleaner energy technologies and electric vehicles, thus contributing to reduced emissions of greenhouse gases and particulates,” the Royal Academy said in announcing the Nobel winners.

The average cost of lithium-ion batteries per kilowatt hour is down about 85 percent since 2010 as a result of economies of scale and advances in the technology, according to Bloomberg New Energy Finance.

Proterra’s Grace said today’s lithium-ion batteries store five times as much energy as the old nickel-metal hydride batteries used in Toyota’s hybrid vehicles. Plus, the cost of lithium-ion batteries has fallen from about $1,000 per kilowatt hour to less than $200, he said.

“It should continue (falling) to approach the holy grail of $80 to $100 per kilowatt hour by 2030 for a full-blown battery pack,” said Grace, who started working in the EV battery space for Tesla in 2007.

A glimpse of the future of EV buses was evident at Busworld Europe 2019, held in Brussels during October:

—Van Hool unveiled its CX45E electric motorcoach with Proterra supplying the batteries. The vehicle’s range is expected to be about 185 miles.

— Volvo Buses showed off its new articulated electric bus, which carries up to 150 passengers.

— Daimler Buses presented its Mercedes-Benz eCitaro, a battery-powered city bus with a range of 105 miles.

In the North American market, Thomas Built Buses Inc., a subsidiary of Daimler Trucks North America LLC, has developed the Saf-T-Liner C2 Jouley school bus, powered by Proterra’s battery packs. The EV school bus charges in three hours and has a range of about 120 miles.

Grace said school buses are well suited for EV technology, since most routes are less than 100 miles per day. EV school buses can be charged overnight and recharged for afternoon service after delivering students to school in the morning.

The Thomas Built Jouley school buses with Proterra battery packs will be assembled in High Point, North Carolina, with production starting in 2020.

As for safety, Grace noted that Proterra has invested millions of dollars in testing its vehicles and battery packs. The company is also involved in safety committees of the Society of Automotive Engineers that are developing guidelines for EV buses that could evolve into federal standards.

Proterra’s battery packs are mounted beneath the floor of its buses between the axles, which provides protection from collisions, isolates them from passengers and lowers the center of gravity for the vehicle.

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