Molicel M65A: Weight v power trade off in pack design - how to pick the right balance.
Explore the Molicel M65A cell for UAV applications, optimising weight and power for enhanced drone performance and endurance.
Value Propositions
Cylindrical 21700 form factor for efficient integration.
Nominal capacity of 23.4 Wh and 6.5 Ah for reliable energy supply.
Volumetric energy density of 914 Wh/l, top-quartile vs median.
Gravimetric power density of 1256 W/kg, +58% vs median.
Maximum continuous discharge of 26 A, top-quartile vs median.
About the Cell
The Molicel M65A is a cylindrical 21700 lithium-ion cell designed for UAV applications, featuring a nominal capacity of 23.4 Wh and 6.5 Ah. With a volumetric energy density of 914 Wh/l, it ranks in the top-quartile compared to the median of 542 Wh/l in the database. The cell also boasts a gravimetric energy density of 314 Wh/kg, which is significantly higher than the median of 210 Wh/kg, making it an excellent choice for applications requiring high energy density. Additionally, the M65A has a volumetric power density of 3655 W/l, which is among the highest in the database, and a gravimetric power density of 1256 W/kg, which is +58% compared to the median of 750 W/kg. This combination of high energy and power densities makes the M65A ideal for demanding UAV applications where weight and performance are critical.
Application Challenges
In the context of EVTOL and the weight versus power trade-off in pack design, the Molicel M65A cell addresses several key challenges. UAVs require batteries that can deliver high energy and power while maintaining a lightweight profile to ensure optimal flight performance. The challenge lies in selecting cells that provide sufficient energy density to extend flight times without adding excessive weight. The M65A's high volumetric energy density of 914 Wh/l allows for more energy storage in a compact form, which is essential for long endurance drone batteries. Furthermore, the ability to discharge at a maximum of 26 A ensures that the UAV can perform demanding tasks without risking battery overheating or failure. This balance of energy and power is crucial for applications such as heavy lift drones and fixed-wing UAVs, where payload capacity and flight duration are paramount.
Why this Cell
The Molicel M65A cell is particularly suited for UAV applications due to its impressive specifications. With a nominal capacity of 23.4 Wh and a maximum continuous discharge of 26 A, it provides a robust solution for drone battery design. The cell's gravimetric energy density of 314 Wh/kg is significantly above the median of 210 Wh/kg, making it an excellent choice for lightweight drone battery packs. Additionally, its volumetric power density of 3655 W/l is among the highest in the database, ensuring that UAVs can achieve optimal powertrain efficiency. This combination of high energy density and power output allows for effective UAV battery optimisation, enabling longer flight times and improved mission endurance.
How Model-Based Design Helps
Simulation and model-based design play a crucial role in optimising the performance of the Molicel M65A cell for UAV applications. By modelling load profiles and thermal behaviour, engineers can predict how the cell will perform under various conditions, such as different flight speeds and payloads. This allows for accurate predictions of voltage sag and usable energy, which are critical for ensuring that the UAV can complete its mission without mid-air failures. For instance, simulating the thermal rise during high discharge scenarios helps in selecting the M65A cell, which has demonstrated excellent thermal performance, thus preventing overheating and ensuring safety. Furthermore, using cell-specific data in simulations enables engineers to make informed decisions about battery thermal management for drones, ultimately leading to more reliable and efficient UAV designs.
