Lecture on Electric Vehicles: Cost and Efficiency

Jul 19, 2024

Lecture on Electric Vehicles: Cost and Efficiency

Key Concepts

Cost Considerations for Electric Vehicles (EVs)

  • Capital Cost vs. Operational Cost:
    • Traditional Internal Combustion Engine (ICE) vehicles: Focus on petrol as operational cost.
    • EVs: Both capital cost (battery) and operational cost (electricity) need to be considered.

Battery Cost and Sizes

  • Battery Sizes:
    • 1 kWh: ₹18,000
    • 2 kWh: ₹33,000
    • 3 kWh: ₹45,000
    • 4 kWh: ₹54,000
  • Usage Efficiency:
    • You can only use a fraction (85%) of the battery's capacity to avoid fully charging/discharging.
    • Effective Capacity: 0.85 kWh for 1 kWh battery, 1.7 kWh for 2 kWh battery, etc.

Range Calculation

  • Based on Watt-hour per km (Wh/km):
    • Example: 1 kWh battery with 15 Wh/km -> 56 km range.
    • As energy efficiency improves (lower Wh/km), range increases for the same battery size.
  • Example Calculation:
    • For 100 km range, 25 Wh/km → ~2.9 kWh battery.
    • For 100 km range, 15 Wh/km → ~1.8 kWh battery.

Energy Efficiency Improvements

  • For different vehicles:
    • Two-Wheelers: Ranges of 15 to 30 Wh/km.
    • Auto: Ranges of 40 to 50 Wh/km.
  • For public vehicles:
    • Reduction in Wh/km through better motors, tires (lower rolling resistance), aerodynamics, and weight reduction.
    • Significant improvements in auto-rickshaws and buses (e.g., buses from 1600 Wh/km to 900 Wh/km).

Swapping Stations vs. Charging Stations

  • Swapping Stations:
    • Advantage: Quick swap (~3-5 minutes) vs. slow or fast charging times.
    • Ideal for: Three-wheelers, public transport, and commercial vehicles.
    • Energy operators own and manage batteries (e.g., IOCL/BPCL model in India).

Range Anxiety

  • Concerns:
    • Limited availability of charging stations.
    • Long charging times.
  • Solutions:
    • Swappable batteries to reduce anxiety.
    • Smaller batteries for shorter ranges with more frequent swaps or supplementary "range extension batteries" for longer trips.

Potential Business Models

  • Swappable Battery Model:
    • Vehicles sold without batteries, reducing initial cost.
    • Energy operators own batteries and manage charging/swapping.
  • Range Extension Batteries:
    • Additional swappable battery for occasional long-distance travel.
  • Conventional Approach:
    • Large batteries with slow/fast charge options, dependent on charging infrastructure.

Assignments

  1. Calculate the size of the battery required for a two-wheeler to get an 80 km range with 25 Wh/km efficiency.
  2. Estimate the cost of the battery using linear interpolation from provided data.

Future Topics

  • Specifications for chargers and batteries.
  • Setting up charging and swapping stations.
  • Profitability analysis of charging and battery swapping business models.