One year before starting production of the Chevy Volt, General Motors engineers say they are confident in the performance and safety of the electric car's batteries.
GM executives gave an update on the car's plans on Tuesday, saying engineers are making some tweaks to the design but that they are on schedule.
The Volt's chief engineer, Andrew Farah, also implied that GM is close to moving ahead with a project to make a Cadillac that uses the same gas-electric power train that the Volt uses. Last week, there were reports that the Converj concept had been given the green light internally, with expected car delivery in 2013.
For the Volt, GM is preparing the battery and auto manufacturing, which will happen in its home state of Michigan, with the process and product validation scheduled to begin early next year, executives said.
In the meantime, GM engineers are testing the Volt's battery pack, called the Voltec, and putting 80 prototype vehicles through the paces. In addition to crash tests for safety, they are testing the car's performance on a range of conditions, including very hot and cold temperatures, and steep hills.
The Volt is a gas-electric hybrid, but unlike the Toyota Prius and other hybrids on the road now, the Volt moves only from electric motors. The gasoline engine is used to supply energy to the batteries through a generator.
Because it's a new car, GM still is trying to project what sort of performance to expect. Overall, engineers are happy, but they also know that climate conditions and driving style will affect the battery's performance, they said.
"Ten years is the target life (for the battery). Depending on how you use it and where you live, you could see significantly longer time," said David Wallace, engineering group manager for Voltec Battery Systems.
The biggest challenge is battery durability in very hot weather, he said. People who live in more temperate areas and do a lot of city driving will have more forgiving conditions, Wallace added.
"But even if you live in Phoenix, as long as you charge at night, and you run during the day, your battery will remain happy," he said.
During its testing, GM has to tune the chemistry of individual batteries, which will be supplied by LG Chem. Various tests, including crash tests, have indicated that battery safety is good, executives said.
For the car itself, auto engineers are now making adjustments to reduce the overall noise during times when the gas engine kicks on for longer rides.
Farah declined to say how big the gas tank will be, which will indicate what the overall driving range is, saying that decision will be made as late as possible.
Separately, Farah said GM's plan to produce an Opel in Europe that uses the Voltec powertrain is still on target, with a schedule roughly one year behind the Volt.