DETROIT— General Motors Co. sold 1,529 battery-powered Chevrolet Volt cars last month, a 34 percent increase from November, amid a U.S. investigation into whether the car’s battery poses a fire risk.

More than one-third of those sales were to corporate fleets; a larger proportion than in previous months when about 10 percent of Volts were bought by corporate and other fleet customers. GM said last month was the first time the company had enough supply to fill orders from corporate buyers, which pay the same price as retail buyers, according to The Wall Street Journal.

The auto maker, worried that the investigation could hurt sales of its high-stakes car, is watching Volt sales closely as it pushes for a resolution to questions a from federal safety regulators about whether the battery could catch fire following a severe crash.

“There has been uncertainty in the market, but we believe that uncertainty will go away,” said Alan Batey, vice president of sales and service for Chevrolet. He said sales will rise as more of the vehicles becomes available.

GM missed its target of 10,000 sales for 2011, the Volt’s inaugural year, by about 2,300 sales. The auto maker says a supply shortages hampered sales and the company has adjusted the way it allocates cars to dealers in an effort to make sure cars are going to the places where demand is highest.

The National Highway Traffic Safety Administration started an investigation into the Volt’s lithium-ion battery pack in November after three of the batteries sparked or caught fire days or weeks after being severely damaged in crash tests. GM has said a coolant leak is behind the problem and it is working on a fix.

The auto maker is targeting 45,000 U.S. Volt sales in 2012. It also plans to export 15,000 of the Detroit-built cars to Europe.

Nissan Motor Co. sold 954 Leaf electric cars in December, bringing its annual tally to 9,674.

GM on Wednesday said its December U.S. auto sales rose 4.6 percent, to 234,351, from a year ago. Full-year sales increased 13 percent to 2.5 million.

DETROIT – U.S. safety regulators are combing over five Chevrolet Volts to determine whether welded parts near the 400-pound battery contributed to fires that occurred following government crash tests.

The National Highway Traffic Safety Administration, in a memo on its website, said it wants to know if crashes caused changes in welded areas on the underside of the vehicle, where the battery rests, reported The Wall Street Journal.

NHTSA asked its test center to take pictures of the vehicle’s “floorplan/crossmember near the battery tunnel,” and asked that the work be done “at the “earliest opportunity.”

General Motors Co. is working with NHTSA to address the issue that caused sparks or fires in three battery packs following crash tests by the agency.

GM engineers believe they can fix the battery and retrofit cars already on the road without an extensive redesign, people familiar with the situation said.

The company says a damaged coolant line is behind the problem.

In the crash tests, a break in the coolant line caused coolant to leak onto wiring in the battery. After time, the coolant crystallized, causing a short.

GM has said repeatedly that the cars are safe. NHTSA said Volt owners shouldn’t worry. No incidents have been reported in real-world driving and the NHTSA fires happened after weeks or days.

Whether GM’s fix is as straightforward as the company believes it to be will depend of NHTSA’s determination of the risk involved in the cars.

If NHTSA determines the Volt presents “a serious risk of injury” it would trigger a process that would lead to a recall, according to the agency’s guidelines.

If not, GM gets to decide what course of action it will take and would not typically require approval from NHTSA.

WASHINGTON — A House panel will hold a hearing next month on the Chevrolet Volt and the Obama administration’s investigation into fire risks in the extended-range electric vehicle.

The announcement came as Transportation Secretary Ray LaHood said Tuesday he believes the Volt is safe. He denied that the government withheld news of a fire in a crash-test vehicle to protect Detroit-based General Motors Co, reported The Detroit News.

“I believe the Volt is safe to drive,” LaHood told reporters after testifying before lawmakers on an unrelated matter.

The House Oversight and Government Reform Committee said Tuesday that one of its panels plans to hold a hearing in late January on the Volt battery issue, according to committee spokesman Jeff Solsby.

The hearing by the committee’s panel on Regulatory Affairs, Stimulus Oversight and Government Spending also will look at the government’s investigation into fire risks.

Rep. Jim Jordan, R-Ohio, chairman of the subcommittee panel, said he wanted to know if the government had been candid about its investigation into the Volt.

“It gives us great concern that recent reports indicate important safety information may have been omitted in testimony before our committee just a few weeks ago,” Jordan said in a statement. “This is a serious situation that our committee will look further into.”

The committee held a hearing on fuel economy standards and heard from officials of the Environmental Protection Agency and the National Highway Traffic Safety Administration.

Questions weren’t asked about safety problems with the Volt.

GM spokesman Greg Martin had no comment on the hearing.

Conservative commentators have sharply criticized the Volt and the government’s investigation, asserting the Obama administration was trying to protect GM. As part of a $49.5 billion bailout, the Treasury still holds a 26.5 percent stake in GM.

LaHood said the government wasn’t trying to protect GM by not immediately disclosing a fire in a crash-tested Volt.

“We’re not in the business of protecting the auto industry. We’re in the business of making sure cars are safe,” LaHood said.

Last month, NHTSA opened a preliminary investigation into the extended-range electric vehicle for fire risks after two fires in Volt battery packs.

One fire happened on Thanksgiving, seven days after a battery pack was crash-tested.

The first was in early June, three weeks after a May 12 NHTSA Chevrolet Volt crash test in Wisconsin.

The blaze burned three other cars. NHTSA didn’t disclose the initial fire — or the fact it had sent letters to automakers asking questions about battery electric vehicles — until early November, when Bloomberg News reported the incident.

NHTSA hasn’t asked GM to stop selling the Volt. It has no reports of real-world fires or complaints.

GM has offered loaner vehicles and has agreed to buy back cars.

General Motors is working on upgrades to the Volt battery containment system to prevent a fire from occurring days after a crash.

DETROIT — In a rare move, General Motors said Thursday that it would buy back Chevrolet Volts if owners were concerned about fire risks. It also promised to comply with any changes to its battery pack recommended by federal regulators.

In an interview with The Associated Press, G.M.’s chief executive, Daniel F. Akerson, defended the safety of the plug-in hybrid vehicle but said the automaker would purchase Volts from unsatisfied customers, reported The New York Times.

A G.M. spokesman, Rob Peterson, confirmed the buyback offer. “If there’s a customer that wants to sell back their Volt, we’ll buy it back from them,” Mr. Peterson said.

Such a buyback is unusual for car companies, which typically institute recalls when regulators or customers report problems with cars or parts. Ford, however, offered to buy back older model Windstar vans last year after investigations into rear axle problems.

The Volt has come under scrutiny after the National Highway Transportation Safety Administration said on Nov. 25 that it had opened a defect investigation into the car’s 400-pound battery pack.

The company on Monday offered free loaner cars to all Volt owners while a federal investigation continued into the potential for postcrash fires in the car’s lithium-ion battery.

Two Volt batteries caught on fire after crash simulations, the agency said. One fire occurred three weeks after the battery was damaged, and a more recent test resulted in a fire one week later. Another pack emitted smoke and a spark in the aftermath of a crash test.

In a separate interview with Reuters, Mr. Akerson said that G.M. would make changes to the Volt’s battery pack if they were recommended by federal officials.

Mr. Peterson said the company would alter the packs “if there’s an engineering solution required.”

Some Volt owners are not concerned about the inquiry. “It just has to be treated carefully in the event of a crash. I really am not worried,” Eric Rotbard, a Volt owner who is a lawyer in White Plains, said in an interview on Monday. “We just have to get more comfortable with the technology. It doesn’t seem to be any less safe to me.”

The latest developments came the same day that G.M. reported that November was the best month for Volt sales since the car was introduced late last year.

G.M. said it sold 1,139 Volts in November, bringing the year’s total to 6,142.

However, the company acknowledged for the first time that it would not achieve its target of selling 10,000 Volts this year, even after allowing dealers to sell demonstration models last month to increase inventory.

The head of G.M.’s Chevrolet division, Alan Batey, said that missing the sales target did not diminish the car’s positive effect on the brand.

“This vehicle is more than just how many do we sell every month,” Mr. Batey said in a conference call with reporters. “It is a magnet around everything we’re trying to do to showcase the brand.”

The Volt was the industry’s top-scoring model in this year’s Consumer Reports customer-satisfaction survey, the publication said Thursday, with 93 percent of owners saying they would buy one again.

G.M. executives have repeatedly defended the safety of the Volt since the federal inquiry opened, noting that there have been no reports of fires in real-world crashes.

The company has asserted that the bigger issue is how the lithium-ion battery is handled by emergency personnel and maintenance technicians after an accident.

G.M.’s product development chief, Mary Barra, said Monday that the car’s battery should be depowered immediately after a collision to avoid any possibility of a fire.

“This is not a conventional automobile,” said Joseph Phillippi, an industry analyst with the firm Auto Trends. “We are talking about high-voltage batteries, and they need special treatment.”

So far, 33 Volt owners have requested a loaner vehicle since the offer was made, and 230 people have contacted their dealers with questions, Mr. Batey said.

General Motors Co., the largest U.S. automaker, will sell its Chevrolet Volt for a starting price of $41,000 and lease terms similar to those on Nissan Motor Co.’s Leaf electric car, Bloomberg reported.

The Volt will be leased for $350 a month with a $2,500 down payment, Detroit-based GM said in a statement. Lessees for the Leaf pay $1 less a month and are required to put down $1,999.

The Volt will sell for a premium over the all-electric Leaf, which is scheduled to go on sale in November for $32,780. The Volt’s lease price and longer driving range on a single charge and tank of gasoline will make it a better choice for most drivers, Joel Ewanick, GM’s vice president of U.S. marketing, said today.

“They’re looking for transportation that will give them no anxiety,” Ewanick said on a conference call. “We’re positioning this as a car first and electric second.”

The Volt’s price includes the $720 freight charge. Tony DiSalle, director of product marketing for the Volt, said GM can offer a lower lease rate than Nissan’s Leaf because the company will have a better resale value than its rival car.

The Volt can travel 340 miles on a tank of fuel, with the first 40 in electric drive before a gasoline engine starts to recharge the battery. The Leaf uses no fuel and can travel about 100 miles on a charge.

GM’s customer research found that car buyers are most worried that they would be stranded if their electric car’s battery ran out of power before they get home, Ewanick said.

The company has set up a website where customers can find a dealer and place an order. The automaker also will have a live phone line staffed 24 hours a day, every day to answer questions about the car.

If there is a waiting list, the company will provide buyers with updates about their place in line and their expected wait. Bayerische Motoren Werke AG used a similar system when it introduced the Mini brand in the U.S. in 2002.

The Volt will initially be sold this year in California and then move to parts of Texas, New York, New Jersey, Connecticut and Washington, D.C. Next year, GM will build 10,000 of the cars and 30,000 in 2012, the company said.

The company has said the Volt will get 230 mpg. The official rating may be different than that figure, Ewanick said.

Nissan CEO Carlos Ghosn has said he plans to sell 500,000 electric cars annually worldwide by 2012. Both cars will be eligible for U.S. government subsidies of $7,500.

Companies such as Automotive Leasing Guide, which sets residual rates, are likely to give a car like the Volt a higher value because it has better range and could find more buyers in the used-car market, said Jim Hall, principal with consulting firm 2953 Analytics Inc, in Birmingham, Mich. Not all buyers can qualify for a lease, so it may not be a large portion of sales, Hall said.

BAY CITY, Mich. — President Barack Obama received his first up-close look at the 2011 Chevrolet Volt earlier this week and now visitors to the General Motors Powertrain plant in Bay City are getting to do the same, The Bay City Times reported.

The vehicle, which GM says can drive about 40 miles on battery power alone and then uses a small gasoline engine connected to a generator to power the electric motor, is on display until 6 p.m. today and from 10 a.m. to 3 p.m. Saturday at the Bay City’s GM Powertrain plant, 1001 Woodside Ave.

But many spectators on Friday said they are concerned with the extended-range electric vehicle’s price, which is expected to be about $40,000.

“The concept seems good, but the price seems a little high,” said Rich McLaughlin, of Monitor Township. “Maybe that will come down.”

McLaughlin, who was at Bay City plant on Friday viewing the four-passenger vehicle, said he likes the car’s appearance and the technology is innovative, but not enough to buy the vehicle if it came out tomorrow.

Brian Essenmacher, a GM calibration engineer for the Volt, drove the vehicle from Milford to Bay City.

When asked to compare the handling of the Volt to another car, Essenmacher compared it to a Pontiac Grand Prix.

“The acceleration — to me — it feels like a Grand Prix,” said Essenmacher, who is at the Bay City plant to help with any questions consumers may have about the vehicle. “It gets up and going.”

When Essenmacher pushed the ignition — or power — button on the car for The Times, the dominating features are two LCD monitors, one in the center of the instrument panel and the other — a touch screen — in the middle of the dashboard.

The instrument panel monitor performs all the tasks a regular instrument panel performs, but also features a variety of other features, including a brake and acceleration monitor measured by a green ball moving up and down.

“It’ll raise up if you’re accelerating hard (and) it’ll turn brown,” Essenmacher said. “You try to keep that green ball where it’s at.”

But even with the Volt’s high-tech gadgets and gas mileage, many spectators agreed with McLaughlin about the expected price of the vehicle being too high.

“I think it’s too much money, even though the government is going to give you $7,500,” said Mark Breza, of Frankenmuth, referring to the U.S. government planning to offer a $7,500 tax credit to anyone who purchases a Volt — in an effort to promote eco-friendly technology and the corporations that engineer them.

Breza, a self declared “car nut,” said he hopes as the technology becomes more mainstream the price will lower, maybe as his daughter looks for a new vehicle.

“Being a young driver, I want something I can afford and this (the Volt) is a good idea, but if they are trying to get young drivers to buy newer cars, they have to make it affordable,” said Ashley Breza, 19.

In August, it was announced the Bay City plant would be getting a $37 million investment from GM to begin production on engine components for the 2011 Chevrolet Volt and Chevrolet Cruze.

The Bay City plant will produce connecting rods and camshafts for the Volt starting Dec. 1, according to Mark Pervine, assistant plant manager. .

“So far everything is on track,” said Pervine, referring to pre-production of the Volt components. “We’re getting everything qualified. Everything is right on target here in Bay City.”