Electric propulsion system developer MagniX has unveiled its plans to produce a new range of batteries for aviation applications. The Samson batteries, announced on June 24, are expected to deliver an energy density of 300 watt-hours per kilogram (Wh/kg) and have a service life of more than 1,000 full-depth discharge cycles.
The U.S. company intends to use the new batteries as an energy storage solution for its family of electric propulsion systems with power ratings ranging from 350 to 650 kilowatts. It will offer the lithium-ion Samson range to other electric aviation companies, as well as other industries.
According to MagniX, the batteries will be available in time to support “the certification and entry into service of our electric engine, and our partnership on the NASA Electrified Powertrain Flight Demonstration program.” It said these milestones are expected to be achieved at the end of 2026, which is later than previously published timelines.
“High energy density typically comes at the expense of cycle life, with many cell chemistries producing only half this number of cycles,” a company spokesperson told AIN. However, it has not explained the basis for the claimed discharge cycle performance or specified the weight for each battery cell.
Washington-based MagniX has been working on applications for its engines to convert existing aircraft such as the Cessna Caravan. In April, Canadian regional airline Harbour Air signed a letter of intent for 50 Magni650 units to convert its de Havilland DHC-2 fleet under a supplemental type certificate. In 2019, the operator flew a MagniX-powered Beaver aircraft, and this prototype has since logged 78 flights.
Under the program with NASA, for which the company was awarded a $74.3 million contract in 2021, a MagniX engine recently completed the first phase of testing at the NASA Electric Aircraft Testbed in Sandusky, Ohio. NASA aims to retrofit a larger de Havilland Dash 7 twin turboprop with electric engines, and MagniX completed the preliminary design review for this conversion in February.
Battery Technology Race Accelerates
In November 2023, Amprius announced that it had signed agreements with three electric aircraft developers to use its latest lithium-ion batteries which have an energy density of 450 Wh/kg. The company has also developed a 400 Wh/kg battery cell system that promises an increased discharge rate of 10C to allow for ultra-fast charging from zero power to 80% in 6 minutes. The 450 Wh/kg batteries have been ordered by an undisclosed eVTOL aircraft developer, according to Amprius.
In Europe, Belgium-based start-up Solithor is developing new solid-state batteries that it has said will achieve energy density in the range of 325 to 350 Wh/kg. It is targeting multiple applications for its pouch cells, including new electric aircraft. In May, it announced that testing of the first-generation batteries achieved 500 cycles at a full discharge with less than a 7% loss of capacity.
Last year, another U.S. electric propulsion system developer, Wright Electric, said it had set up a new business unit to develop batteries that could deliver an energy density as high as 1,000 Wh/kg to support megawatt-class engines. The company is working on a two-megawatt electric engine that could support single-aisle airliners.
“With the development of our Samson batteries, MagniX can now offer customers a fully integrated electric powertrain, and it’s just the beginning,” said the company’s CEO, Reed Macdonald. “The roadmap to an energy density of 400 Wh/kg or more is looking very promising.”
MagniX intends to produce the Samson batteries in-house and also through various external partnerships. The first product in the series will be the Samson300, and the new family is being developed to support greater range and payloads for electric aircraft.
According to MagniX, its patented technologies include cell-level protection from thermal runaway and the ability to store batteries for long periods of time without losing charge. The Samson architecture is intended to support fast turnarounds for aircraft on the ground, with active ground cooling during charging and optional passive cooling in-flight.
The Samson batteries include an integrated power electronics and distribution system to support power management for propulsion systems. They will be available in modular configurations to support larger electric aircraft in the future.