Title
Ultra High-power and lightweight battery pack for small aircraft
AbstractA German SME seeks to optimize the powertrain of an electric vertical takeoff and landing (eVTOL) passenger aircraft for urban air mobility (UAM), that is planned to go into series production. Thus they are looking for lightweight batteries with high power and voltage stability. Partners sought are developers and manufacturers of battery packs for technical or commercial agreements. Tasks to be performed are the identification of fitting battery cells and their assembly.
DescriptionA German mechanical engineering firm has, in cooperation with its partners, developed an electric vertical takeoff and landing (eVTOL) passenger aircraft for urban air mobility (UAM). It is an all-electric tandem wing aircraft with excellent flight characteristics. The demonstrator has successfully passed all remote controlled and crewed flight tests and is to go into series production soon.
It has a front propeller for forward flight, eight fixed propellers for VTOL flight, tandem wings, a rear vertical stabilizer, and a three-piece rear landing gear with wheels. All components including the electric drives, batteries and control systems are designed to be fully optimized. The airframe is extremely light at 255 kg (562 lbs) maximizing the flight range of the aircraft. The aircraft has Distributed Electric Propulsion (DEP) which provides safety through redundancy for its passengers.
The demonstrator has two independent battery packs. One battery pack is optimized for long endurance cruise flight, the other battery pack is optimized for peak power during hover and VTOL flight.
The German SME now seeks to optimize the aircraft’s powertrain by integrating lightweight battery packs with a better energy performance.
• As weight is very important for flight performance, small batteries with ultra high power are required. Batteries are fully drawn within 3 to 4 minutes.
• Voltage stability is also very important, because if the voltage falls below a certain threshold value, the motor can no longer reach its maximum speed. This is defined by the internal resistance.
The company seeks technical cooperation agreements or commercial agreements with technical assistance. Possible partners are developers and manufacturers of battery packs. Task to be performed by the desired partner is the identification of suitable battery cells and their assembly. The testing of the battery packs can be done on the German company’s testbench on-site.
Advantages and innovation
Technical Specification or Expertise Sought
• Capacity to weight ratio greater than 170 Wh/kg
• Inner resistance battery pack smaller than 10 mOhm
• Capacity 500 Wh
• 60 V nominal voltage
• 200 A continuous current
• 400 A peak currents
• Only air cooling with propeller