Assemblers are building battery packs for the much-anticipated Chevrolet Volt, which will hit the market later this year. General Motors is using lithium-ion battery cells supplied by LG Chem Ltd. and its U.S. subsidiary, Compact Power Inc.
Battery cells will be assembled into T-shaped packs and then shipped to GM’s Detroit-Hamtramck plant, where the Volt will be assembled. There are more than 200 cells in each 360-volt battery pack.
“The capability to manufacture advanced batteries in-house is a tremendous competitive advantage,” claims Bob Kruse, executive director of GM’s global vehicle engineering for hybrids, electric vehicles and batteries. “With the Brownstown battery plant, we can control the entire development and production of this technology.”
The new assembly plant will provide more than 100 jobs and is part of a wholly owned subsidiary of General Motors called GM Subsystem Manufacturing LLC. It was constructed with funds provided by the U.S Department of Energy as part of its Electric Drive Battery and Component Manufacturing Initiative.
The battery plant features three primary assembly areas: Battery module pre-assembly, final assembly and battery pack main line. The pre-assembly area is where cells are processed and installed into one of three battery modules, which are ultimately joined together to comprise a single battery pack. Final assembly and testing of the modules takes place in a nearby area of the plant.
The second part of GM’s battery plant is where final assembly and testing of the modules takes place. Automated welding equipment performs hundred of welds on each battery. Operators perform manual leak testing and electrical testing.
Once built and tested, the modules move via conveyor to the battery pack main line for final assembly. That’s where assemblers attach hoses, straps and electrical connections. The main line is also where battery pack final testing, verification and packaging for shipment takes place.
The Brownstown Battery Assembly plant uses flexible manufacturing layouts, as well as equipment, to enable operators to quickly respond to volume or product changes in the market. For instance, automated guided carts are used for flexible material handling.
According to Gary Cowger, GM group vice president, manufacturing and labor relations, the automaker will use “a rapid pre-assembly system to drive accuracy and repeatability” in the plant. “The manufacturing challenge we face is to process a single cell every 2.7 seconds or, at full production, 70,000 cells per day.
“In the future, when we have a number of different battery packs in production, this plant will be able to adjust [work flow] based on market demand,” Cowger points out. “We’ll [also] use a number of tools to ensure quality in every phase of the battery assembly process.”
The Chevy Volt will be GM’s first extended-range electric vehicle. The 16-kilowatt-hour battery assembled at the Brownstown plant will form the heart of the automaker’s Voltec electric propulsion system. It consists of 150 unique parts. General Motors engineers designed all but eight parts.
The Volt, which is scheduled to start production late this year as a 2011 model, will be capable of travelling up to 40 miles on electricity from a single battery charge. A flex fuel-powered engine-generator will extend its overall range to more than 300 miles. Full production at the Brownsville battery plant will begin in the fourth quarter.
