Last week, Oxis Energy announced an agreement with Bye Aerospace of Denver, Colorado, to develop a proof-of-concept lithium-sulfur battery cell for Bye’s future electric airplanes. Soon, the Oxfordshire-based company hopes to do something similar for eVTOL aircraft.
An Oxis Energy spokesperson told eVTOL.com that it has applied for an Innovate UK grant “with a large aerospace company targeting urban air mobility specifically.” The proposed project would last for five years and target the development of a lithium-sulfur cell with an energy density of 400 Wh/kg discharged at 2C continuously.
“We also aim to develop and demonstrate a proof-of-concept battery for eVTOL,” the spokesperson said, noting that the company expects the project to be awarded in the fourth quarter of 2019.
Aviation is one of several target markets for Oxis, which is also exploring opportunities in the defense, marine, and electric vehicle spaces. According to CEO Huw Hampson-Jones, the company’s lithium-sulfur cells and battery systems are ideally suited for aviation because of their light weight — over 50 percent lighter than current lithium-ion cell and battery systems, he said.
The project with Denver, Colorado-based Bye Aerospace will commence in September 2019, and will initially address the development of electric propulsion for aircraft with two to nine seats, including aircraft intended for regional rapid air taxi transportation. One of these is the eFlyer 4, a four-seat evolution of Bye’s two-seat eFlyer 2 training aircraft.
“New lithium-sulfur battery cells from Oxis have the potential to greatly enhance the quality, cost, and performance of eFlyer 4 and our other future aircraft projects,” stated Bye Aerospace CEO George Bye, noting that the company’s collaboration with Oxis is separate from its current agreements for the eFlyer 2. “Oxis has the potential to provide a lithium-sulfur battery cell that is truly a game-changer.”
Oxis said that through ground tests in Europe, it has already demonstrated a significant improvement in simulated flight duration for lithium-sulfur cells compared with lithium-NMC (nickel manganese cobalt oxide). The company will now undertake a further series of tests to provide a “robust indication” of the performance of its lithium-sulfur technology.
“A key measure of Oxis’ suitability is to be able to consistently produce cells in excess of 400 Wh/kg, which are already undergoing evaluation,” said Hampson-Jones. “Oxis expects to achieve 500 Wh/kg by early 2020.”
The aim over the next 18 months is to move toward production of commercial cells and battery systems in order to meet the volume roll-out criteria set by Bye Aerospace, Oxis said.