Estonia-based ultracapacitor developer Skeleton Technologies closed a €41.3m ($48.3m) series D round yesterday that included electrical equipment producer Harju Elekter.
EIT InnoEnergy, the sustainability-focused fund backed by the European Institute of Innovation and Technology, also took part in the round, as did venture capital firm FirstFloor Capital, investment firm MM Grupp and undisclosed private investors.
Founded in 2009, Skeleton produces ultracapacitor cells, modules and systems that make use of ‘curved graphene’ technology, for use in energy storage. Its technology is used in car batteries, grid-scale energy storage systems and industrial machinery.
Taavi Madiberk, Skeleton’s co-founder and CEO, said: “The momentum for energy transition and decarbonisation of the economy is stronger than ever. I am proud to see that our investors strongly believe in our vision and we now have new world-class mix of industrial companies and experienced startup leadership behind us.
“Their experience will now help us scale and aggressively grow. We have the right products to capture a dominant market share in the ultracapacitor industry globally.”
The company said it has now secured about $109m altogether, having received $14.6m in a 2016 series C round led by FirstFloor Capital and backed by Harju Elekter and Up Invest, before getting a $16m loan from European Investment Bank the following year.
Harju Elekter led Skeleton’s $11m series B round in 2015, taking a 10% stake and participating alongside Up Invest, which had led the company’s $5.2m series A the year before.
