Battery reliability is ‘mission critical’ if ambitions for all-electric aircraft are to be realized. Now a UK start-up backed by NATEP is pioneering the use of predictive maintenance to help make this happen.
A reliable strategy is to start small and scale up, which could be the mantra for Faraday Batteries, the UK start-up behind a new NATEP-supported project called Predictive Maintenance of Electric Aircraft Batteries (PEAB).
Midlands-based Faraday Battery has just embarked on a 12-month 30% match-funded project to develop its battery technology, initially for the electric vertical take-off and landing (eVTOL) market. Its academic partner is Coventry University’s Centre for E-Mobility and Clean Growth Research (CEMR). Faraday Battery’s chief executive Sanjay Gupta says their work is ultimately targeted at sustainable aviation and the all-electric aircraft, and with the first electric commuter aircraft due to enter service around 2026, followed by the first electric short-haul narrowbody around 2030, that opportunity is fast approaching.
Faraday Battery was launched in 2019 on a vision of battery-powered transportation that is affordable and thus ubiquitous. The company has six patents pending on thermal management and proprietary electronics incorporated in its innovative battery pack.
“We use familiar lithium ion cells as the building blocks,” said Gupta. “Our innovations provide all-weather protection and a very long life which, depending on usage, can be more than 10 years.”
No hard shoulders in flight
PEAB will help the partners move into air transport “where, in the familiar comparison with automotive, there are no hard shoulders.”
Predictive maintenance is not new but has gained traction with advances in the internet of things (IoT), cloud computing and machine learning. With batteries, typical signs of stress arise from overcharging or discharging, which lead to cell failure, rapid degradation and shortened working life.
PEAB will help the project partners resolve questions around reliability, and therefore safety, in the battery Faraday is developing which Gupta describes as “a second generation battery”, the first generation being those used in current electric cars.
Typically, if something is wrong, fluctuations in temperature and unusual sounds will indicate a fault, said Gupta.
“The problem is few things in the battery world are detectable. With a complex system such as an aircraft using a large number of battery cells, it’s almost impossible to know if one of them has a latent fault.
“Not all faults result in failure; not all faults are a safety risk.”
Second approach to predicting failure
Faraday started tackling this challenge through machine learning. Under PEAB, the partners are developing a second approach to predicting failure, and therefore the optimum time to replace batteries, using physics and mathematics.
Dr Cheng Zhang, assistant professor at CEMR, said many years of battery research at the university have identified which parameters to monitor with the use of algorithms. Any abrupt change could indicate a pending fault, he said. “At this stage what is being detected by the sensors is not yet a fault; it’s not even detectable by mechanical means.”
This is a “huge” step beyond current battery management systems (BMS) which mainly measure current, voltage and temperature. “Traditional BMS is a threshold monitor: it’s reactive, where what we’re building is proactive.”
Gupta said the partners expect to have results by June 2023. “Time will tell how accurate we are in predicting. It needs a lot of data.
“What will success look like? If both models give similar results and the whole system works.”
NATEP’s support will be instrumental in bringing this innovation to market, initially in the eVTOL space, where predictive maintenance will be a standard feature of the Faraday Battery pack.