GM's Battery Strategy and Approach to Future Volt Generations

The 2010 Chevy Volt





General Motors has revealed its strategy for the future and its commitment to the electrification of the automobile. This article examines the current state of the Volt battery and how GM will "reuse" components and use them across a wide variety of vehicles. Then, GM explains the future of the battery and what we can expect in second and third Volt iterations.

From Green Car Congresss:

Three key General Motors executives involved with the Chevrolet Volt this week held a media briefing on the state of GM’s battery pack strategy for the Chevrolet Volt and its current Gen 1 pack as well as subsequent generations (Gen 2 and Gen 3) of battery packs destined for the underlying Voltec platform. They also delivered an update on the progress of the Volt’s development cycle.

Executive Director of Global Engineering–Hybrids, Electric Vehicles, and Batteries Robert Kruse, Volt Vehicle Chief Engineer Andrew Farah, and Director of Global Battery Systems Engineering Denise Gray took turns describing work completed so far as well as next steps for the project.

GM is emphasizing the role of thermal management and control systems in the overall pack and vehicle performance. Click to enlarge.

Kruse took particular care to note that, while having an excellent battery cell is important, the cell is just the starting place. GM views its value-add to the overall pack—and hence to the vehicle—as the thermal management and electronic controls. That rationale lies behind the company’s determination to manufacture the modules and packs for its vehicles in its own plant. (Earlier post.)

Kruse said that GM has developed all the software, electronic controls and pack engineering in-house, and that the process will continue with the portfolio into the future. GM regards the ability to do so as a core competency, and GM therefore made the strategic decision to have that capability inside the company.

Undertray of the Volt, showing the integration of the T- shaped battery pack as a structural element. Click to enlarge.

The current state of the Volt. More than 30 mules—similar-sized Chevrolet vehicles that have been modified to accept Volt powertrains—are already up and running, with another 50 expected to be built and put through their paces by the summer.

The team reiterated its commitment to the Volt’s 40-mile all-electric range (AER), especially as compared to a vehicle with the attendant costs of a battery pack with a several-hundred-mile all- electric range, but said that no commitment had yet been made on the business model (e.g. sale or lease) that will be employed for the Volt’s 16 kWh battery pack when the vehicle goes on sale November 2010, a date to which GM remains “confident and committed,” according to Kruse.

Undercarriage of the Volt during the 35 mph crash test. The battery pack is the orange T-shaped element. Click to enlarge.

A 35 MPH frontal crash test has already been conducted on at least one Volt mule to the satisfaction of the company, with particular emphasis given to the integrity of the battery pack during the test. Kruse also emphasized GM’s preference for fast charging as opposed to the “battery swap” model promoted by Better Place, which would require a significantly different chassis design and which Kruse termed “problematic”.

“We began in January 2007, we are on track, and I think in some places we have accelerated our learning,”" commented Denise Gray, who runs GM’s battery development labs, which the company says are the largest in the country. “We spent all of 2008 evaluating cells.”

Despite current market conditions, GM is still aggressively developing talent from within the company, with fifty engineers currently enrolled in a “learn while you earn” program related to the Volt, and another 50 expected to be transferred to the program this summer.

While officials emphasized that they are satisfied with the chemistry, thermal management, controls, and performance of the vehicle’s current battery pack, costs per kWh remain high, and development beyond the current pack is primarily focused on cost reduction. Gray noted that the costs of battery-powered personal electronics have declined sharply and expressed optimism that the transport sector might see similar gains. Each of Volt’s 200-plus battery cells will initially be produced in South Korea by LG Chem. However, GM plans to move battery production to the US as soon as possible.

Although the team declined to specify a cost per kilowatt-hour for the Volt during the briefing, Jon Lauckner, Vice President of Global Program Management, rebuffed speculation earlier this month, writing on the GM Fastlane blog (earlier post) that the current Volt battery pack is “many hundreds of dollars less” than the US$1,000 per kWh cited in a recent Carnegie Mellon study, and that “new concepts” promise to move the cost to as low as $US 250 per kWh.

Remarking that “I’m only going to do this job once,” Kruse mentioned another cost-cutting measure: the decision to design the global platform to more stringent European Union recyclability standards.

Gen 2, Gen 3 and Reusability. GM, said Kruse, is “thinking long term with our EV strategy.”

We are making a significant investment in vehicle electrification in the Volt, the Voltec powertrain and the battery itself. We believe that vehicle electrification is the future of the industry...and that master of battery technology is key to us and our success. We still have a lot of work to do. We are very encouraged by what we have done so far, and are gaining optimism with experience and exposure.

Because of our commitment, we have resources working on Gen 2 and Gen 3 [battery packs] while we are still launching the Gen 1 system. That speaks to our long-term commitment to vehicle electrification.

—Bob Kruse

GM’s “reuse” strategy. Click to enlarge.

The primary motivation for the Gen 2 and Gen 3 systems is to reduce cost, to make it more viable for the mass market, Kruse said. The GM team did not engage in a deeper discussion of the potential relative contribution of cells, thermal management and controls to reducing the cost in Gen 2 and Gen 3, but Kruse did say that “as we get close to production, we’ll take the cover off of the T pack, and you’ll see the sophistication and elegance of design.”

Kruse did outline what GM is calling its “reuse” strategy in the battery area—i.e., the ability to apply cells, modules and packs across different vehicles:

• Cells. Cells of the same specification will be widely applied in a range of vehicles.

• Modules. Cell modules will be used across a class of vehicles/applications.

• Complete packs (including controls). Complete packs will be applied across vehicles within a architecture. The Volt pack, for example, will be applied in the Opel Ampera.