The BMW i3 is an electric vehicle that has evolved through 3 generations from 2013 until 2022. Originally designed as an EV with optional range extender to overcome the lack of range available from the original battery design. The battery capacity and performance has gradually evolved to a battery pack size that doesn’t really need the range extender.
The prismatic cell from Samsung SDI that is used in this pack has steadily increased in capacity from 60Ah to 94Ah and 120Ah in the final design.
Battery Pack Generations
The BMW i3 was ahead of the game with a single rectangular layer of 8 modules with 12 cells in each module. This allowed the engineers to create a simple design with a very high cell to pack mass ratio.
2013
- Total energy = 21.4kWh
- Usable energy = 18kWh
- Cell
- Samsung SDI
- 60Ah prismatic
- 108Wh/kg
- active refrigerant cooling
2016
- Total battery capacity: 33.77 kWh
- Usable battery capacity: 27.2 kWh
- Battery weight: 256 kg
- Battery energy density: 132 Wh/kg
- Cells: 96 (96s1p)
- Cell
- Samsung SDI
- 94Ah prismatic
- 172Wh/kg
- active refrigerant cooling
2017
Mostly cosmetic updates to the vehicle, but the power output increased from 127kW to 135kW for the s version.
2018
- Total battery capacity: 42.2 kWh
- Usable battery capacity: 37,9 kWh (90 %)
- Battery weight: 278 kg
- Battery energy density: 152 Wh/kg
- Cells: 96 (96s1p)
- Cell:
- Samsung SDI
- 120Ah prismatic NCM 622
- 200Wh/kg
- active refrigerant cooling
The BMW i3 design in terms of cell to pack mass ratio was class leading as can be seen in the graph below. The latest Cell to Pack (CTP) designs from BYD and CATL have just improved on this.
References
- BMW I3 Batterypack teardown, youtube