Wednesday 29 September 2010

Energy Density - Myth and Legend


Cell and battery manufacturers often promote their technology and products in terms of Energy Density to demonstrate stored energy with regard to both weight and volume.

Gravimetric Energy Density (GED) is expressed in Watt Hour per Kilogram (Wh/Kg) while Volumetric Energy density (VED) is expressed in Watt Hour per Litre (Wh/l). These figures are useful to battery designers and device manufacturers as they allow comparison between different battery technologies, different cell sizes and different manufacturers.

It is commonly known that out of the three mainstream technologies used for portable batteries, Lithium Ion has the highest energy density with Nickel Metal Hydride in second place and Nickel Cadmium coming in third which explains the transition away from Nickel based chemistries over the past ten years.

The following chart shows the energy density of various cells based on data taken from commercially available data sheets, this clearly demonstrates the advantages of Lithium Ion Technology.


To learn more about energy density please read my article on the Accutronics website.

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