Pack Gravimetric Energy Density

Pack Gravimetric Energy Density has the units Wh/kg and is a key pack metric. The optimum metric is a high Wh/kg. Hence:

• High nominal voltage
• High Ah capacity
• Low mass

The best you can achieve will be less than or equal to the cell Wh/kg that the pack is made from.

Perhaps the simplest of the battery metrics as the capacity of the cell is fairly easy to measure and the mass is just a set of scales.

The only note of caution is the discharge rate at which the cell Ah capacity has been measured. For automotive C/5 to C/3 is quite representative for a range test. However, for a phone or laptop C/10 is perhaps closer. Most cell capacities are quoted by manufacturers at C/10.

• 261 Wh/kg 2023 NIO ES6 150kWh
• 218 Wh/kg Mercedes Vision EQXX
• 174 Wh/kg 2022 Ford F-150 Lightning Extended Range
• 171 Wh/kg 2023 Ducati V21L Moto E
• 171 Wh/kg 2021 82kWh Tesla Model 3
• 168 Wh/kg 2019 Renault Zoe ZE 50
• 161 Wh/kg 2022 Tesla Model Y 4680
• 155 Wh/kg 2020 BMW iX3 80kWh GEN5 Battery
• 150 Wh/kg Tesla Model 3 long range version
• 148 Wh/kg 2019 Porsche Taycan Turbo S
• 148 Wh/kg 2018 Jaguar I-Pace
• 147 Wh/kg Formula E Gen 2 Battery Pack 2019-21
• 101 Wh/kg Formula E Gen1 Battery Pack 2014-18
• 80 Wh/kg 2011 Nissan Leaf
• 37.2 Wh/kg Toyota Prius Gen 2 hybrid pack

Plotting this energy density versus total energy in the pack is as expected.

The roadmap of pack energy density for battery electric vehicles is interesting. Mean pack-level gravimetric energy density for BEV road cars has tracked an almost perfectly linear ~3.4 Wh/kg/year improvement since 2019, lifting the fleet from ~146 Wh/kg to ~162 Wh/kg, with the 2026 cohort (small, n=5) already averaging 175 Wh/kg. The best-in-class line tells the more dramatic story: top packs have moved from ~180 Wh/kg in 2019 to 257 Wh/kg in 2023.

Electrified Aircraft Propulsion Targets

In aircraft the gravimetric energy density is one of the key targets at pack level. As of 2022 the 400Wh/kg target from NASA is a very tough target when automotive packs are achieving ~170Wh/kg.

NASA state in their November 2021 presentation that they have the following requirements for the battery pack:

• 400 Wh/kg required at the system level
• 1000’s of cycles
• Extremely high power requirements (C-rates) during takeoff and landing
• Cruise power for long range flights
• High reliability, limited maintenance
• Improved safety for thermal runaway events

Battery Pack Database

An excel file with hundreds of battery packs and thousands of datapoints. Check your design against other designs to ensure the metrics stand out from the crowd.

Battery Pack Mass Estimation

This is one of our calculators that lets you estimate the mass of the battery pack based on the cell mass and total energy content.

This applies to automotive HV battery packs.

See also: Pack Mass