Life Cycle Analysis

The Life Cycle Analysis (LCA) of a battery is quite complex and hence the intention is to cover that in posts. First though we need to breakdown the stages:

Cell Manufacture

energy consumption Yuan et al
Energy Required to Make a Cell

The cell manufacturing process requires 50 to 180kWh/kWh.

Note: this number does not include the energy required to mine, refine or process the raw materials before they go into the cell manufacturing plant.

The global warming potential for two popular cell chemistries[2] and the main drivers for these values:

  • NMC811 = 76.7 kg CO₂ eq. per kWh
    • nickel sulfate production (cathode)
    • graphite production (anode)
    • energy for drying processes
  • LFP = 77.9 kg CO₂ eq. per kWh
    • lithium carbonate production (cathode active material manufacturing)
    • graphite production (anode)
    • energy for drying processes
carbon footprint of a battery cartoon image
Carbon Footprint vs Cell Chemistry

How does the carbon footprint change with cell chemistry? With the EU Battery Passport and India’s Battery Pack Aadhaar Number we are looking for all the levers we can use to improve our battery pack designs.

The carbon footprint of manufacturing a battery cell varies significantly, with estimates ranging broadly from 10 to 394 kg CO2-equivalent per kilowatt-hour (kg CO2-eq/kWh). These emissions are heavily influenced by the region of production and the carbon intensity of its local electricity grid; for example, current average footprints are around 69 kg CO2-eq/kWh in the European Union and 87 kg CO2-eq/kWh in China.

The total lifetime emissions of a battery is dependent on the emissions generated in making it and how long it lasts, hence “Carbon Footprint is a 2-axis Problem”. Hence if we select a chemistry that has higher initial emissions but lasts much longer we could overall have a lower impact on the planet.

GHG Intensity vs cycle life for a battery cell and calculated lifetime emissions per kWh throughput of energy

Mining

Mining of the raw materials is extensive based on the materials used within a battery cell. However, we need to extend that to the complete battery pack.

Transport

Every form of transport has a kgCO2 equivalent per kg of material transported per km travelled impact.

DEFRA [3] give results for a number of modes of transport:

  • Van = 0.645 gCO2eq/kg.km
  • HGV = 0.154 gCO2eq/kg.km
  • Rail = 0.037 gCO2eq/kg.km
  • Plane = 0.727 gCO2eq/kg.km
  • Container Ship = 0.019 gCO2eq/kg.km

References

  1. Phoebe Whattoff, Jordan Lindsay, Robert Pell, Carolina Paes, Alex Grant, Laurens Tijsseling, The Growing Importance of Life Cycle Impact Data in the Battery Material Supply Chain, Minviro Ltd 2021
  2. R. PELL and J. J. LINDSAY, Comparative Life Cycle Assessment Study of Solid State and Lithium-Ion Batteries for Electric Vehicle Application in Europe, Prepared for The European Federation for Transport and Environment 20th January 2022
  3. DEFRA freight transport methodology, CarbonKit

Related: for the formal definitions behind these numbers (GWP, Scope 1/2/3, cradle-to-gate vs cradle-to-grave), see Embodied Carbon & GWP: Definitions and System Boundaries.

Battery Value Chain

The battery value chain looks at the whole eco system from mining the raw materials through to recycling.

The value is perhaps normally thought of simply in terms of financial returns, but this eco system needs to look at many factors:

  • money
  • skills
  • trade
  • industrial base
  • environment

See also: ISO 14040, ISO 14044, Battery Basics