Battery testing and modelling company About:Energy has measured a specific energy of 504Wh/kg in BEI’s MUL20A lithium-metal cell, the highest figure it has recorded in its independent testing.
About:Energy’s co-founder Kieran O’Regan said the South Korean manufacturer’s cell was the first tested by his company to exceed 500Wh/kg.
The result was obtained at a C/5 discharge rate, compared with BEI’s advertised 519Wh/kg at the slower C/10 rate. About’s measurement therefore reached approximately 97% of the manufacturer’s rated specific energy despite the higher discharge current.
Independent testing: BEI had not paid for the result
O’Regan said BEI had not paid for the result. About:Energy is now testing the cell under representative drone and electric vertical take-off and landing aircraft mission profiles to assess performance under application-specific loads.
The MUL20A uses an anode-free design, with lithium deposited on the negative current collector during charging instead of being stored in a conventional graphite electrode. Removing the graphite host reduces cell mass and creates more room for energy-storing material.
Manufacturer specifications published in About:Energy’s Voltt database list a nominal capacity of 21.1Ah, energy of approximately 81.5Wh and mass of 157g. The pouch cell is rated at 1,281Wh/L, with a maximum continuous discharge current of 100A. These specifications are manufacturer figures, separate from the reported 504Wh/kg test result.
BEI announced a KRW30 billion Series B funding round in July, including investment from In-Q-Tel, to expand production and customer supply. The company said more than 30 global drone customers were evaluating its battery technology, with some already using it in operational applications.
