Toyota Readies Plug-In Test Cars and We Drive One; Company Developing Lithium Ion Batteries

Toyota Readies Plug-In Test Cars and We Drive One; Company Developing Lithium Ion Batteries

Plug-In Prius Headed to U.S. for Tests, but Floral Decals To Stay in Japan 

TOKYO — Toyota Motor Co. has been pretty conservative in its approach to plug-in hybrids with extended electric vehicle range from rechargeable batteries that can be rejuvenated from the commercial power grid.

It seems  the automaker has decided to eschew words in favor of action.

Turns out that engineers and technicians at Toyota's Higashi-Fuji Technical Center have been working on plug-ins for three years now, and are about ready to start testing a modified version of the company's popular Prius hybrid — outfitted with a bigger bank of nickel metal hydride batteries and a plug-in system that will let them be recharged from a standard 100-volt household outlet.

The idea is to use existing technology to provide a taste of what Toyota believes the Prius will act like once it can be outfitted with lighter and more powerful lithium ion batteries — and although the company is unwilling to say when, it is pretty telling that Toyota is willing to admit that it's curious to see what advanced battery technology could mean to what already is the world's leading hybrid car. The testing comes to the U.S. later this month as Toyota begins on-the-road development studies in conjunction with researchers at the University of California's Irvine and Berkeley campuses.

This week the carmaker let a small group of journalists get behind the wheel for a run around a short circuit set up on the test track at the 496-acre technical center that lies in the shadow of Japan's sacred Mt. Fuji.

Short Drive Tells a Lot

Four miles isn't a lot of distance — or drive time — in which to evaluate a vehicle, but Green Car Advisor can report that the plug-in Prius test mules delivered on the few promises Toyota has been willing to make about its hopes for the technology.

These aren't our neighbors' Priuses.

They are capable of traveling up to 7.7 miles on battery power alone, and seemed quicker than the conventional Prius, even though neither the electric motor nor the gas engine has been altered.

Although one of the test cars seemed plagued by balky software that kept it from switching easily between all-electric and blended gas engine and electric modes, the other worked like a charm.

It accelerated easily to 62 miles an hour without asking the gas engine for any help and, according to the battery charge indicator on the dash board, could have been driven at that speed on battery power along for almost 8 miles. 

Yoshikazu Tanaka, chief engineer for the plug-in Prius project, who sat in the passenger seat during our drive, confirmed that the instruments were accurate.

When pushed —as if accelerating hard to reach freeway speed at the top of a short on-ramp, the plug-in Prius test car's gas engine did kick in, but it dropped out and let the batteries and electric motor take over as soon as pressure on the accelerator was eased.

At speeds above 62 mph, or when asked for more power than batteries alone could deliver, the car's power management system pulled the gas engine in to service. Toyota said we weren't supposed to exceed 62 on the test track, but we kicked it up a bit on a long straightaway and the car lunged forward in a decidedly un-Prius-like manner.

A power management display on the dash lets the driver keep an eye on what's happening beneath the sheet metal.
Dotted lines on the dashboard display connect batteries to electric motor to drive wheels when the car is in electric mode; a solid line appears and connects the engine icon to the wheels when the gas engine kicks in.

Above that schematic, a power graph shows a blue bar that measures acceleration and a green and red bar that shows when the electric motor is engaged (green) and when the gas engine is helping out (red).

The extra power is provided by a doubled-up nickel metal hydride battery pack that adds about 220 pounds of weight to the car and raises the floor of the cargo hold — beneath which it is installed — by about an inch.

We'd need to drive the test vehicle for a week on our Southern California freeways to provide a more detailed impression, but at first glance the system seemed to work fine.  And in every other respect, it was a Toyota Prius: quiet, smooth, comfortable and well-built.

We won't get that week behind the wheel — not right away, anyhow — but putting the test cars through their paces is what the University of California researchers will soon be doing.

They'll be collecting driving impressions, measuring fuel economy, charting performance characteristics and user impressions, and piling up data Toyota can use to evaluate the plug-in technology.

Toyota Cautious but Confident

Tanaka and Yoshitaka Asakura, general manager of Toyota's hybrid systems engineering division at Higashi-Fuji, wouldn't say when Toyota hoped to replace the nickel metal hydride batteries with lithium ion and said repeatedly that reliable lithium batteries simply don't exist, yet.

And the company is far more cautious than rival General Motors, which has said it intends to launch a plug-in "extended range electric vehicle" with lithium ion batteries and a 40- to 60-mile all-electric range. GM has said the car, called the Volt, will be an affordable member of the Chevrolet family, possibly priced at or below $30,000.  
 
But Toyota—often criticized for its conservatism and rather cool attitude toward plug-ins—hasn't been sitting around waiting for someone else to score the big battery breakthrough. "We're in a hurry," one executive said.

Company executives and engineers won't say how far along the development path they are, and voice concern that there may not be a terribly enthusiastic market for a plug-in gas-electric hybrid.

Environmental groups, hybrid and electric vehicle fans and even some government agencies have enthusiastically endorsed the idea of a vehicle that can travel in all-electric mode at highway speeds for a short time using batteries that can be recharged from the commercial grid.

But that's a fairly small percentage of the population, said Asakura. The Sierra Club might like the idea, but at Toyota "we wonder if, after we extend the regular hybrid market, whether people will want to plug in." he said.

Despite his deep involvement in the plug-in Prius project, Asakura said his own wife "does not accept charging [a car] every day."

Bill Reinert, manager of advanced technology for Toyota's U.S. division, said that adding lithium ion batteries that would enable a Prius-sized car to travel just 15 miles on electric power along could add $10,000 to the cost of the car.

The present Prius starts at $20,950, and the thought of a 50 premium premium for a plug makes Toyota executives nervous — even though a $31,000 price tag would put a rechargeable Prius in the same ballpark as GM's Volt.

Still, Toyota is plugging away on improvements to both the nickel metal hydride batteries used in almost all hybrids today, and the lithium ion batteries carmakers say would provide more power at less weight if overheating and reliability issues can be overcome.

"We are extensively studying" lithium ion technology, Asakura said.

John O'Dell, Senior Editor, Green Car Advisor

John O'Dell:  is an AutoObserver Senior Editor. Follow @AutoObserver on Twitter.