Skeleton Technologies, which claims to be Europe's leading producer of ultracapacitors for transportation and the grid, has pulled in new funding.

The Estonian graphene ultracapacitor maker secured €9.8 million ($10.7 million) in Series B financing at the beginning of June.

The funding round was led by Nasdaq OMX Tallinn-quoted Harju Elekter Group (HAE1T), which owns electrical equipment manufacturing plants in the Baltic markets, and previous investor UP Invest, one of largest investment firms in the region.

Harju Elekter acquired 10 percent of Skeleton Technologies as part of the transaction. Skeleton Technologies CEO Taavi Madiberk told GTM the investment will be used to expand current manufacturing capacity in Bautzen, Germany.

The company is also preparing to launch a new product for the trucking sector before the end of July. For now, the company plans to target an exclusive group of high-end ultracapacitor users.

“We will focus on high-tech customers to reach $150 million [in turnover] by 2020,” Madiberk said.

Skeleton’s current customers include the European Space Agency plus unspecified global engineering companies, Tier 1 automotive manufacturers, and U.S. defense agencies.

Madiberk said the power and energy densities of Skeleton’s SkelCap products made them attractive to premium customers looking for high performance. According to Skeleton, the SkelCap triples the power densities of competitor products from Maxwell and Ioxus.

It has a power density of 60 kilowatts per kilogram, compared to 21 kilowatts per kilogram for Ioxus and 18 for Maxwell. In terms of kilowatts per liter, the SkelCap scores 84 versus 31 for Ioxus and 24 for Maxwell. Skeleton also claims superior energy densities for its products.

It says the SkelCap delivers 14 watt-hours per liter and 10.1 watt-hours per kilogram, compared to 7.3 watt-hours per liter and per kilo for Maxwell and 6 watt-hours per liter and per kilo for Ioxus.

A 5.7-kilowatt SkelCap ultracapacitor weighs 178 grams and is 0.124 liters in volume, in contrast to a Maxwell equivalent that delivers 5.5 kilowatts but weighs 510 grams and is 0.4 liters in volume.

This means Skeleton’s technology can deliver 80 kilowatts in five seconds from a 25-kilogram unit, while competitors would need 75 kilograms ofstorageto achieve the same performance. 

To round out the comparison, Skeleton says the SkelCap only loses 1 percent of energy as heat, compared to 3 percent for Ioxus' and Maxwell’s products or 30 percent for a standard lithium-ion battery.

Skeleton says these technical advantages, which are covered by four patents (with another 16 pending), are mostly due to its use of graphene. “Skeleton Technologies is the only manufacturer to use graphene in ultracapacitor cells,” said the company in a press release.

“The company uses a patented material synthesized from inorganic compounds that has curved graphene layers allowing for better conductivity and higher surface area.”

At present, “We have demand at an order of magnitude higher than we can manufacture,” said Madiberk.

However, there are no plans at this stage to bring in third parties to help. “We are expanding the current manufacturing capabilities that we have,” he said.

Skeleton is focusing on high-value customer segments partly to achieve a faster return for its investors, but also because the purchase cycles are quicker with such clients, said Madiberk. The firm is not ignoring the possibility of wider applications, however.

“We are looking to exploit the premium market and mass-market niches where we can bring most value,” Madiberk commented. “We have to choose sweet spots. We select specific uses for the mass market where [there are] weight and volume restrictions.”

The current focus on premium applications should also help Skeleton get the customer references it needs to establish its reputation in other markets.

Madiberk confirmed his company was in talks with two leading European original equipment manufacturers, but added that “certification cycles take four or five years.”

The latest funding gives Skeleton a solid backer with which to plan for those time frames. Harju Elekter, established in 1968, today claims to be one of the biggest manufacturers of electrical equipment and materials in the Baltic Sea region.

“We are convinced that ultracapacitor-based solutions will increasingly be used in electrotechnical and manufacturing automation applications for energy storage, control and high-power fast switching,” said Harju Elekter Group CEO Andrus Allikmäe in press materials. “Our participation in this field gives us the ability to cooperate in potential future applications and also creates a synergy in participating in the development of ultracapacitor modules.”