(Reuters) -- The Chevrolet Volt stands as the most heavily promoted - and harshly scrutinized - vehicle from General Motors Co in decades. And that's just version 1.0.
Amid the debate, one aspect of the Volt has escaped the notice of fans and critics alike: the roadmap for potential upgrades GM left buried deep inside.
A bolt-by-bolt, surgical deconstruction of the Volt attended by Reuters without the involvement of GM showed how the plug-in hybrid was designed for relatively quick upgrades such as a longer driving range under electric power.
By leaving what amounts to a blank slate at the heart of the Volt's complicated electronic controls, GM has cleared the way - if the Volt succeeds - for the quick improvements more common in consumer electronics than the slower-moving auto industry, analysts said.
The glimpse of GM's ambition for future versions of the Volt comes at a make-or-break moment for the vehicle, designed to provide 40 miles of pure-electric driving range before a gasoline-generator kicks in to keep it rolling.
Chief Executive Dan Akerson sees the Volt's electric-drive technology as an area where GM leads rivals like Toyota Motor Corp and has pushed to drive it into other vehicles so it can start to make money for the U.S. company.
The Volt is one of the first mass-market electric cars. It differs from its closest rival, the Nissan Leaf, by having a gasoline-powered engine to provide additional driving range once the battery is spent.
Toyota has a competitor to the Volt, a plug-in version of the Prius, coming later this spring.
GM has a lot riding on the success of the $40,000 Volt because of its status as a halo car meant to lure consumers to the Chevy brand and prove a once-stodgy automaker can be cutting-edge.
The Volt has been on sale in the United States-since December 2010, but only about 9,000 have been sold. A now-closed U.S. safety investigation after battery fires had threatened to overshadow the car's positive publicity and derail GM's plans to take it to overseas markets including China and Germany.
Analysts who watched the Volt's dissection in a suburban Detroit warehouse said GM left unused space on its circuit boards for more computing power to improve performance in future models. The Volt design also suggests a development plan for other GM electric vehicles, they said.
They're reserving a lot of this real estate for future development so that they can easily put more components on here if they want to, said John-Scott Thomas, a senior engineer at UBM TechInsights, holding a circuit board from the Volt's battery pack.
OPENING THE BATTERY
Over three days, engineers for Munro & Associates took apart the Volt at the consulting firm's Troy, Michigan-based warehouse headquarters. They catalogued every step of the process, removing almost 600 parts, including doors and seats until they reached the car's heart -- its T-shaped, 400-pound battery pack.
These kinds of teardowns are standard behind closed doors in the industry as automakers attempt to reverse-engineer rival vehicles, but Reuters was invited by UBM and chip industry publication EE Times, which performed a similar deconstruction in 2007 on Toyota's Prius, the top-selling hybrid car credited with lifting the automaker's reputation for fuel economy.
GM engineers and a key supplier acknowledge they had the future in their plans from the beginning with the Volt.
This heavy emphasis on advanced electronic systems management was a deliberate program priority, said Bob Lutz, GM's former vice chairman and one of the executives who championed the Volt's development in 2006 when GM was under fire and slipping toward bankruptcy.
The Volt's circuit boards point to the next steps in the vehicle's evolution, said analysts at the teardown. They also expect GM to apply Volt lessons to future vehicles like the all-electric Chevy Spark planned for 2013.
This is, without a doubt, the most advanced board I've seen General Motors put out and it's got room to grow, Munro Chief Executive Sandy Munro said. This is hot stuff.
Holding up a circuit board with 32-bit Freescale Semiconductor chips from the Volt's inverter, UBM's Thomas called it more of a development board. This is their first pass.
There are places here where you can see that it looks as though you should be able to put an integrated circuit and there's nothing there, he said. They might already have plans to add that in at a future date.
GM officials say they are already working on improvements. We do want to try and design more performance in the car, maybe get a little more EV range for our money, chief Volt engineer Doug Parks told Reuters.
DOUBLE THE FIREPOWER
The Volt is already chock-full of technology, sporting about 20 Freescale chips or double the number in a more typical car with only an internal combustion engine, Memta Patel, manager of Freescale's GM team, said in an interview. Freescale and Japan's Renesas Electronics hold about two-thirds of the $23.6 billion global auto chip market.
Freescale executives said GM engineers were conservative with the Volt layout as the automaker raced to bring the plug-in hybrid to market.
They didn't have as much time to do as many redesigns, Freescale auto field engineer John Cotner said. Risk reduction was a more important factor than it is in a lot of vehicle design.
Cotner said Freescale and GM for at least 18 months have been looking at the next generation of technology and going to fewer, smaller modules in electric vehicles. Freescale and GM officials declined to say whether Freescale chips are part of the Spark battery.
Parks agreed GM played it safe with the Volt design since the technology is still new and GM wants future batteries for instance to be more refined and efficient.
GM has repeatedly defended the Volt's safety since U.S. safety officials launched the investigation in late November studying the risk of battery fires.
The National Highway Traffic Safety Administration closed its probe last month, saying the car was as safe as its gas-powered peers and the agency was satisfied with GM's plans to strengthen structural protection for the lithium-ion battery and to prevent coolant fluid leaks that could trigger a fire.
The end of the probe and GM's fix have not quieted congressional Republicans, some of whom have decried the federal $7,500 tax credit for electric vehicles.
GM has not backed away from its support of the car and executives say the Volt was not rushed into production.
It is the most significant step ever in GM's history to give customers a choice beyond oil, a technological 'moon shot,' GM's Akerson said in a letter published in several newspapers last month after NHTSA closed its probe.
GM will apply lessons learned from the issues linked to the NHTSA probe, Parks said.
You can be assured that on Spark (battery electric vehicle), we're going to make sure we do lots of testing and let batteries sit around in cars after crash tests and make sure we don't have any coolant leakage, Parks said.
More detail on the Volt teardown can be seen at UBM Electronics' website dedicated to the car, www.driveforinnovation.com.
(Reporting by Ben Klayman in Detroit, editing by Matthew Lewis)