Pack Size versus Application

Battery pack size versus application is an interesting comparison.

  • iWatch ~1Wh
  • Mobile ~ 10Wh
  • Tablet ~30Wh
  • Laptop ~50Wh
  • eBike ~500Wh
  • Home PV storage ~10kWh
  • Electric Car ~100kWh
  • Electric Lorry ~500kWh

The plot is based on real data from real products in the market and shows total battery pack size.

The Y-axis is a logarithmic scale and hence the eLorry battery is nearly 6 orders of magnitude, or 1 million times, bigger than the smart watch battery.

Pack Sizing

The usable energy (kWh) of the pack is fundamentally determined by:

  • Number of cells in series (S count)
  • Number of cells in parallel (P count)
  • Capacity of a single cell (Ah)
  • Nominal voltage of a single cell (Vnom)
  • Usable SoC window (%)

Energy (kWh) = S x P x Ah x Vnom x SoCusable / 1000

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