# Formula E Battery 2019-21

The Formula E Battery 2019-21 or Gen 2 pack was designed and made by McLaren Applied and Atieva, using a Murata cell.

Note: very few details of this pack have been published and so the specifications are a best estimate based on the numbers that are available.

### Specifications:

• total energy = 56.6kWh
• usable energy = 52kWh + 2kWh for car recovery to pitlane
• 54/56.6 = 95%
• peak discharge power kW10s and kW1s at %
• 200kW during race
• 250kW during practice
• continuous power [W]
• nominal voltage = 756V
• capacity = 74.88Ah

The cells have a nominal capacity of 3.12Ah and configured as 24p hence 74.88Ah. The rated minimum capacity is 3Ah and this would give 72Ah and a pack minimum capacity of 54.4kWh.

• voltage range = 525V to 882V

For the first Formula E battery pack the voltage quoted in the press was the maximum pack voltage. Hence it has been assumed that this logic has been carried across.

• weight [kg] = 385kg
• cells = 234.9kg (defined by FIA spec)
• volume pack = 320litres (as given in tender specification)

Our assumption is that the battery pack as designed has used all of the available 320 litres of volume.

• pack dimensions [m] =
• module =
• number of cells = 5040
• 210s (see estimate below)

The maximum Formula E system voltage is 880V and the Murata 18650VTC6 maximum voltage is 4.2V this gives a cells in series count of 880V / 4.2V = 209.54s which we would round to 210s

• 24p (see estimate below)

The cell has a nominal capacity of 3.12Ah at 0.2C and this drops to 2.85Ah at 1C and 2.7Ah at 10C.

Assuming minimum rated 3.0Ah

p = 54000 / (3.6 x 210 x 3.0) = 23.8

p = 24

This then gives a total number of cells of 210 x 24 = 5040

The Murata 18650VTC6 weighs 46.6g and hence total cell mass = 5040 x 46.6g = 234.9kg.

• charge time <45 minutes for 0-100% (defined by FIA spec)
• cell format = cylindrical 18650
• modules: the pack is designed based on a modular system, this design was a prototype for the Lucid Air battery pack.
• cooling system = dielectric cooling
• operates between 25 and 35°C cell temperature
• 3M dielectric fluid
• cell make and model
• Murata 18650VTC6
• pack cost = \$235,000

### Key Pack Metrics:

• Gravimetric energy density, pack = 147 Wh/kg
• Cell = 241 Wh/kg
• Volumetric energy density, pack = 176 Wh/litre
• Gravimetric power density, pack = 649 W/kg10s
• Volumetric power density, pack = 781 W/litre10s
• Estimated cost = \$235,000 / 56.6kWh = \$4152/kWh
• Cell to Pack mass ratio
• module to pack mass ratio = 234.9 / 385 = 61%
• Cell to Pack volume ratio

Also, these specifications and metrics can be cross-correlated to check their legitimacy.

### Other key features:

• Safety
• BMS
• HV Distribution
• HV and LV Connections
• Cooling Connections
• Structural / non-structural pack
• Case material
• Sealing strategy
• Venting strategy
• Durability
• Season mileage: 6000 km
• Battery life: 1 season
• Cycles: 150
• Availability
• Recycling
• Shipping

Also, if you have images of the battery that we can use to illustrate more of the design features then do let us know (editor). Or in fact if you have data on other packs that we can share on our benchmarking pages then do let us know.

### References:

1. McLaren Applied – Formula E Battery – announcement page that states they will be making the battery pack.
2. Murata – US18650VTC6 specification
3. Formula E – Energy Management: The Key to Formula E Strategy
4. FIA Formula E Battery Tender 2016

#### 2014 to 2018 – Williams Advanced Engineering

The Formula E battery pack 2014-18 was the first generation battery pack and was developed by Williams Advanced Engineering and supplied to every manufacturer in the series.

#### Formula E

The Formula E series is designed to push the forefront of EV technology. Hence the specifications get more demanding each year and make a jump in design at each generation. There are now two battery packs that we have explored in detail and a third on the horizon.

This is our Battery Pack Benchmarks and hence we would like to understand if this is useful and how we could improve it. Also, if you have material that could be added to improve it or we should link to.