Bruel & Kjaer UK Ltd. - PRODUCT NEWS

Chevy Volt Uses LDS Vibration Test System for Electric Vehicle Battery Durability Tests

Hybrid power technology development is ramping up globally in today’s ultra competitive automotive industry – and these technologies of the future demand vibration test solutions that can efficiently perform accelerated lifetime tests even on large and fully operational assemblies.

General Motors’ 3000m2 battery test laboratory at The Alternate Energy Center, Warren Technical Center, Warren, Michigan, USA tests battery cells and packs for the Chevrolet Volt electric vehicle – and an LDS Vibration Test System is used for electric vehicle preproduction qualification and functional test of a complete T-shaped battery assembly designed to be mounted underneath the car. The weight of the battery unit can exceed 190 kg.

The Chevrolet Volt is an electrical vehicle. Hailed as the spiritual and technological successor to the EV1, it will be launched in November 2010 as a 2011 model and has a “Voltec” extended range propulsion system.

Anthony (Tony) Cullen has worked for GM for 20 years, mainly for the Milford Proving Ground Group. He has been involved with the GM-Volt battery vibration test lab since it came online in the second quarter of last year. Today, he is Lead Test Engineer for the vibration room in the laboratory. The battery test lab has seven Lead Test Engineers, four of whom are dedicated to battery testing, and one each for cell, vibration and abuse testing. GM has announced that it will expand the battery test lab in Warren to almost double the size and add capacity during the coming months. The current, state-of-the art lab began operations in January 2009 and is used by more than 1000 engineers to test cells, modules, and entire packs.

Tony says: “The development of the Volt is unique with its on-board generator. It uses kinetic energy to
charge the lithium-ion batteries and a standard Volt in urban driving conditions will do 40 miles [64 km] on a full battery charge”. He continues, “Once the energy in the battery reaches a specific level, the on-board 1.4 litre gasoline engine takes over and powers a generator to supplement the battery. The engine and generator now supply power for the vehicle, and everything is automatically controlled by sophisticated onboard computer systems”.

“The main purpose of the vibration lab is to test the battery’s durability by simulating its lifecycle. The targeted lifetime of the battery is ten years. In addition to vibration, various other tests such as thermal and mechanical fatigue are carried out. The random vibration test lasts for 48 hours, that is, 48 hours of random vibration input and shock pulses. The data to power the shaker is acquired from a Volt on the GM proving ground. They test the battery in the x, y and z axes – one at a time – and each axis test takes
16 hours.”

Vibration testing also takes place in a climatic chamber where temperature and humidity are strictly and closely controlled. The environment in the climatic chamber can range from – 30°C to +78°C, and each 16-hour axis test is carried out under controlled temperature and humidity conditions. To meet GM’s testing demands, the system used had to be high-performing and versatile and easily adaptable to several
test demands on large heavy payloads in multiple axes.

The LDS Vibration Test System delivered perfectly fulfils GM’s requirements for a heavy-duty system, able to perform accelerated durability test simulating the lifetime of the car. This includes several days of continuous testing at very high vibration levels and extreme temperatures.

About Bruel & Kjaer
Brüel & Kjær is a world-leading manufacturer and supplier of sound and vibration solutions for use in a wide range of applications including environmental noise measurements, building acoustics, vibration measurements and quality control for use in the automotive, aerospace and consumer industries, as well as by local authorities. Today Brüel & Kjær has 900 employees and sales offices in 55 countries. Brüel & Kjær is a subsidiary of UK-based Spectris plc. ( Spectris has annual sales of approximately £656m and employs around 6000 people worldwide in its 15 business units.
For more information, please contact :-

Bruel & Kjaer UK Ltd.
Jarman Way, Royston, Herts. SG8 5BQ. UK
Tel: +44(0) 1763 255 780
Fax: +44(0) 1763 255 789

September 2010

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