The Leaf's battery needs 20kg of lithium but 40kg of graphite, the Tesla Roadster's battery needs even 100kg of graphite. While discussions about the scarcity of lithium were vivid 1-2 years ago and have now ebbed down, nobody has discussed yet the supply of graphite, indispensable anode material, to facilitate a large uptake of electric mobility.
While EV uptake might be not as fast as forecast last year, investments into battery plants are still high. GS Yuasa invests $300 (~ €245) million to expand their battery production facilities, LG Chem invests the same amount in a li-ion battery plant in the US to supply the Chevy Volt, Russia had announced to put $420 (~ €342) miilion into completing the world's largest li-ion battery plant.....But if only 5% of cars worldwide were to become electric, current graphite production would need to double, says Greg Bowes, CEO of Northern Graphite (see exclusive interview tomorrow), who has a graphite mine development project in Bissett Creek, Ontario, Canada.
Graphite - the anode material of choice
Graphite has already been the anode material of choice for the alkaline batteries in the 1950ies, passing by the nickel hydrogen batteries in the 1970ies, the nickel metal-hydride in the 1980ies and finally the lithium-ion batteries since the 1990ies. Batteries are the fastest growing end use for graphite and EVs hold the potential to see graphite demand boom.
Why is graphite so popular as anode material?
The anode requires a porous carbon material and graphite is the optimum match. Graphite is also:
- easy to machine (not true of natural graphite, only synthetic)
- very resistant to thermal shock
- does not melt in the battery (melting point at above 3,600°C) which reduces wear
- has a density 5x lower than copper and is therefore lighter
- is insoluble in water, acids & bases;
- is not corrosive
How much graphite does one EV battery pack need?
There are 3-10 kgs of graphite in the average HEV and 25-50 kgs in an EV. Estimates are that increasing demand for lithium carbonate will reach 286,000 tonnes by 2020. This would mean a six fold increase in annual flake graphite production to provide material for that many batteries. Graphite demand in li-ion batteries in 2008 was already estimated at 44,000 tonnes, i.e. ~ 10% of the flake graphite market - with a persisting upwards trend.
The Nissan Leaf, for example, is equipped with a 24kWh battery pack containing 20 kg lithium carbonate and 40 kg graphite. The Tesla Roadster needs 100kg graphite for its 56kWh battery pack. The average recharge time of the Tesla Roadster is 3.5h, average range 400 km and average battery life 160,000km.
Only spherical (potato shaped) graphite can be used in batteries. This requires flake graphite to be upgraded to 99.95% purity - an expensive process that wastes 70% of the feedstock of flake graphite. Therefore, spherical graphite sells for more than 3 times the price of flake graphite. currently $6,000-8,000 (~ €4,900-6,500 per tonne.
World Production
China dominates world graphite production and represents 75% of total output. India is the second largest producer followed by Brazil, north Korea, Austria and Canada.
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