An EV is a shortened acronym for an electric vehicle. EVs are vehicles that are either partially or fully powered on electric power.
Electric vehicles have low running costs as they have less moving parts for maintaining and also very environmentally friendly as they use little or no fossil fuels (petrol or diesel). While some EVs used lead acid or nickel metal hydride batteries, the standard for modern battery electric vehicles is now considered to be lithium ion batteries as they have a greater longevity and are excellent at retaining energy, with a self discharge rate of just 5% per month. Despite this improved efficiency, there are still challenges with these batteries as they can experience thermal runaway, which have, for example, caused fires or explosions in the Tesla model S, although efforts have been made to improve the safety of these batteries.
It can cost as little as £7.80 to fully charge an electric car from home and can even be free in public car parks.
There are two main types of electric vehicles (EV); fully electric and plug-in hybrids:
Battery Electric Vehicles (BEV)
Compared to an internal combustion engine, battery electric vehicles have approximately 99% fewer moving parts that need maintenance.
Advantages of a BEV:
- Creates very little noise
- No exhaust, spark plugs, clutch or gears
- Doesn't burn fossil fuels, instead uses rechargeable batteries
BEVs can be charged at home overnight, providing enough range for average journeys. However, longer journeys or those that require a lot of hill climbs may mean that the fuel cells require charging before you reach your destination, although regenerative braking or driving downhill can help mitigate against this by charging the battery packs.
The typical charging time for an electric car can range from 30 minutes and up to more than 12 hours. This all depends on the speed of the charging station and the size of the battery.
In the real world, range is one of the biggest concerns for electric vehicles, but is something that is being addressed by industry.
Plug-in Hybrid Electric Vehicles (PHEV)
Rather than relying solely on an electric motor, hybrid electric vehicles offer a mixture of battery and petrol (or diesel) power. This makes them better for travelling long distances as you can switch to traditional fuels rather than having to find charge points to top up the battery.
Of course, the same disadvantages that apply to combustion engine vehicles also apply to PHEVs, such as the need for more maintenance, engine noise, emissions and the cost of petrol. PHEVs also have smaller battery packs, which means a reduced range.
TWI has been instrumental in the development of electric vehicles, assisting with light-weighting of the vehicles themselves, helping with joining and welding, mitigating against battery combustion and more.
Find out more about TWI’s work with electrification