Canadian Manufacturing

Cadillac using ultrasonic welding on electric coupe battery packs

High-tech manufacturing process used to join metal electrode tabs to 2014 ELR batteries



DETROIT—General Motors (GM) says the plant building batteries for its new extended-range electric Cadillac will employ ultrasonic welding equipment to ensure uniformed quality in the high-end coupe.

Used at the automaker’s Brownstown Battery Assembly plant near Detroit, ultrasonic welding is utilized to join metal electrode tabs on the 16.5-kWh lithium-ion battery system used to help power Cadillac’s all-new 2014 ELR extended-range electric luxury coupe.

Traditionally used in the aerospace and medical industries, GM says the key advantage to ultrasonic welding is exceptional and predictable quality and performance from one battery pack to the next.

And with close to 200 ultrasonic welds in each ELR battery, the high-tech manufacturing process helps the automaker offer an eight-year, 100,000-mile battery system warranty.

other advantages of the process are its short cycle times, low capital costs and manufacturing flexibility through the use of automation, according to the automaker.

“Ultrasonic welding is a far superior joining technology in applications where it can be deployed,” Jay Baron, president and CEO of the Center for Automotive Research in Ann Arbor, Mich., said in a statement.

“Cadillac’s innovative process will produce batteries with superior quality compared with traditional methods—and do it more efficiently. This is one example of technology development that is becoming pervasive in today’s world class vehicles.”

Ultrasonic welding uses specialized tools called an anvil and horn to apply rapid mechanical vibrations to the battery’s copper and aluminum electrodes.

This creates heat through friction, resulting in a weld that does not require melting-point temperatures or joining material such as adhesives, soldering or fasteners.

An integrated camera vision system is used to shoot a reference image of the weld area prior to the operation to achieve pinpoint accuracy.

GM's Brownstown Battery Assembly plant near Detroit uses ultrasonic welding to join metal electrode tabs on ELR’s lithium-ion battery. PHOTO GM

The battery-specific welding process is a result of collaboration among GM’s Manufacturing Systems Research Lab and Advanced Propulsion Center and the Brownstown plant.

GM first applied the process on the Chevrolet Volt.

“This effort is an outstanding example of teamwork between research and manufacturing engineering,” GM’s vice-president of global manufacturing engineering Catherine Clegg said.

“It has helped integrate the use of highly technical, complex technology into a sustainable manufacturing process, which means we can consistently deliver high-quality batteries to our customers for the Cadillac ELR.”

The ELR’s T-shaped battery pack is located along the centerline of the vehicle, between the front and rear wheels for optimal weight distribution.

The 5.5-foot, 435-lbs. pack supplies energy to an advanced electric drive unit capable of 295 lb.-ft. of instant torque to drive the vehicle.

Using only the energy stored in the battery, the ELR will deliver an estimated range of about 56 kilometres of pure electric driving.

The Cadillac ELR is built at GM’s Detroit-Hamtramck Assembly Plant, one of the few high-volume electric vehicle manufacturing facilities based in the United States.

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