Environmental records: manufacturing
The manufacturing of a vehicle makes a relevant contribution to its environmental record. For combustion vehicles, this accounts for around 15% of the overall balance in terms of the greenhouse effect; for electric vehicles it is usually considerably higher. Although these do not have combustions engines, manual gearbox or exhaust gas treatment systems, they do have an electric motor and a traction battery. The manufacturing ratio depends greatly on the battery size – for a medium-sized vehicle (range of around 100 km, operated with conventional electricity) it is around 30%, so double that of a combustion engine.
The most important parameter for the manufacturing-related environmental effects of a vehicle is its size because a majority of the effects are proportional to the use of material. For electric vehicles, however, the battery is also a crucial factor. Lithium-ion batteries are most commonly used today. They feature a high energy density and are not subject to any memory effect – their capacity is retained even when partially discharged.
For current electric cars, the battery is responsible for almost half of manufacturing-related environmental effects. This is also because the lifespans of today’s batteries are usually shorter than that of the vehicle (guarantees from vehicle manufacturers currently stretch to around 100,000 km). For the current evaluation, we therefore assume that the battery will have to be exchanged once in every second vehicle.
A glimpse into the future
To date, lithium-ion batteries have been used primarily in the consumer electronics sector (mobile phones, laptops etc.). Their use in cars in some ways requires modifications and improvements, primarily in relation to lifespan and safety in accidents. In the field of battery development, a great deal of research is currently being undertaken with the primary aim of increasing energy density, improving temperature stability and extending the service life. For batteries in the year 2030, significant advances will therefore be mandated in UMBReLA that lead to the manufacturing-related environmental effects of electric vehicles becoming ever closer to those of conventional vehicles (see illustration).
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Manufacturing-related greenhouse gas emissions, currently and for three different scenarios in the year 2030 (IFEU 2011)
Furthermore, the use of lightweight vehicle design technologies will also play a role. Lightweight material construction requires a particular steel quota to be replaced with a lightweight construction material (e.g. aluminium). Although this increases the manufacturing-related environmental effects (because the production of aluminium is more energy intensive that that of steel), this is however balanced by energy savings during vehicle operation. Viewed over the entire lifespan, this reduces greenhouse gases. In the moderate and innovative scenario of 2030, UMBReLA assumes an increase in aluminium lightweight designs (see illustration). In future, carbon fibres could also play an important role in lightweight automotive design, as their weight reduction potential is very high (with equally high charging capacity), and they offer good recycling opportunities. However, a good deal of development work is still required in this area.
In addition there are further lightweight construction options which aim to minimise the use of materials in the vehicle.
- Last Updated on Friday, 03 May 2013 20:06