What is the weight of the batteries on the e-Fan? Airbus' own (early) page with technical data about the e-Fan provides some information about the batteries.

It can, for instance, be calculated that they hold approx. 19kWh of energy if you accept a somewhat simplistic calculation by multiplying number of cells (120) with capacity (40A ) and voltage (4V).

What I can't find is information about the weight of these batteries. Is this information available somewhere or can it be reasonably estimated?
The weight of the battery is mentioned here:


  Power is provided by 127 kg. of 250-volt lithium-ion polymer batteries
  from Kokam in South Korea built into the wing.


A slightly different weight is specified here:


  ... E-Fan has two lithium-polymer battery packs weighing 65 kg each.


I could not find which Kokam battery is being used on the e-fan, but this page has specifications for all of their batteries.