California-based startup NDB claims it is poised to offer a diamond-based alternative to current battery technology that will be more efficient and sustainable for electric aircraft. On August 25, the company announced it has completed proof-of-concept tests on its self-charging nano-diamond battery, achieving what it claims is a breakthrough 40 percent charge, compared with charge collection efficiency rates of just 15 percent with commercial diamonds.
NBD also announced it signed two undisclosed launch customers—an aerospace, defense, and security manufacturer, and a Europe-based nuclear fuel cycle products company—for a beta version of the technology. Electric aircraft and vehicles are among the anticipated early adopters of the technology.
The privately-owned company is now working on the first commercial prototype of its nano-diamond battery and aims to have this available by year-end. It said the proprietary self-charging process will provide a charge for the full lifetime of any device or machine, with up to 28,000 years of battery life.
The power source for the nano-diamond battery is intermediate- and high-level radio isotopes that are shielded for safety by multiple levels of synthetic diamond. According to NDB, the energy is absorbed in the diamond through a process called inelastic scattering, which is used to generate electricity.
Since the battery is self-charging, which requires only exposure to natural air, any excess charge can be stored in capacitors, super-capacitors, and secondary cells. It does not require any external power source and also incorporates a DC-to-DC converter to control the current. Additionally, NDB said, the diamond batteries do not require materials sourced in conflict zones or those that could be ecologically damaging.
“A 40 percent [charge] efficiency has never previously been achieved due to [previous] material choices and our proprietary technology has achieved this breakthrough in efficiency,” NDB’s CEO and co-founder Nima Golsharifi told AIN. “What we have achieved competes with what is available from traditional fossil fuels in terms of energy density, and it is not climate- or light-dependent [like other sustainable power sources].
A 40 percent charge rate means that 40 percent of the charge generated by the radio isotopes was collected using the diamond technology. By comparison, solar power cells typically have a charge collection efficiency rate of around 15 to 20 percent.
NDB believes it will be able to achieve a 90 percent rate of charge. This further progress could result in smaller, lighter batteries being available.
The company is now engaged in research work aimed at supporting the use of nano-diamond batteries to power eVTOL aircraft. The work is supported by the U.S. government’s defense and energy departments.
According to Golsharifi, the batteries will provide sufficient power to support cruise flight for unmanned aircraft. The company expects to build a commercial prototype of the battery within the next three years. It said that the diamonds that encase the isotopes are more than 11 times stronger than the materials used for battery cases and able to withstand temperatures of up to 3,632-deg F.
The proof-of-concept testing was conducted at the Lawrence Livermore National Laboratory in the U.S. and at the Cavendish Laboratory at the UK’s Cambridge University. Experiments were led by Professor Sir Michael Pepper, a pioneer of semi-conductors and winner of the Institute of Physics Isaac Newton Medal.
This story comes from the new FutureFlight.aero resource developed by AIN to provide objective, independent coverage, and analysis of new aviation technology, including electric aircraft developments.