The lithium ion car battery is one of the latest advances in battery technology for electric cars. Lithium-ion batteries have higher densities than earlier batteries, but much lower densities than conventional fuels.
Energy Comparisons
One of the most important parameters for any transportation fuel is energy density. Gasoline and diesel fuel pack a lot of energy into a relatively small volume, as you can see on the charts below. Lithium-ion batteries by comparison pack a lot less energy into the same space. This is why electric cars have lower ranges compared to gas powered cars.
Here is an energy/unit weight example comparison: The 2010 Nissan Leaf has a 200 Kg (440 lbs) lithium-ion battery pack. Then: 0.20 kWh/Kg x 200Kg gives a theoretical 40kWh. Actually, the pack holds 24kWh. We will not consider the volume relation here.
Now, regarding the energy density of the lithium-ion car battery: Compare lithium-ion energy to the energy density of gasoline at 13.11 kWh/Kg. 200Kg of gas would equal a whopping 2622 kWh! That's over 100 times as much energy! That's the equivalent of a 1,000 watt portable Honda generator running day and night for 3 months! No wonder oil company stock is so popular and EVs are so challenged.
Battery Improvements
The lithium-ion car battery is under rapid development and improvement. Lithium batteries go by several names based on their chemistries. Li-Ion and LiFePo4 are a few of the more common configurations these days. The Envia company for instance promises a 400 Watt-Hour battery weighing just 1.0 kg.
This type of battery packs more energy into a lighter case than the lead acid or nickel-metal hydride batteries shown above. This allows the EV to carry more energy for the same weight. The Li-Ion battery can also be recharged quickly, especially using a proper charging station.
In a cool video, you can see the construction of lithium EV batteries here. Note that as with other batteries, Li-Ion battery charging must be done safely.
One drawback of Li-Ion batteries is that they tend to be a bit unstable. Remember those laptop fires? Those were Li-Ion laptop batteries burning. Those are also the same types of batteries found in the Tesla Roadster. Tesla and other EV manufacturers have designed cooling systems and redundancy into the power systems to prevent lithium related flareups.
Remember, however, that even the Tesla Roadster with 900 lbs of fully charged Li-Ion battery pack carries the actual energy of about 2 gallons of good old gasoline weighing 12.5 lbs. The Tesla's impressive acceleration is due to the inherent torque characteristics of its rather large electric motor and light weight. Its range is due to its efficiency, light weight, great design, and rather low drag.
There is a huge amount of research going on to improve Li-Ion batteries even more such as efforts to extend range and reduce charging time among other things.
The Li-Ni battery represents a possible improvement. Other recent Li-Ion car battery research efforts are listed on this site.
Technical news on lithium-ion and other types of batteries may be found at ABT.
To get a sense of how fast lithium battery research and development is proceeding, check here.
The US Federal Government is funding 9 Li-Ion battery plants that are expected to begin producing EV battery packs by 2011. Government funds have helped finance 26 out of 30 new US battery and component plants expected to supply up to 20% of the worlds EV batteries by 2013.
Lithium Facts
Lithium is the present battery chemistry of choice.
Lithium is the lightest metal, about 1/2 the weight of water. However, pure lithium ignites on contact with water.
The largest lithium deposit is in the Salar de Uyuni in Bolivia. The deposit covers 10,582 sq km or 4,086 sq mi. This deposit is around 50-70% of the world total. The area is not now in mining due to governmental restriction.
Most lithium is produced by:
Chile's SQM produces about 32,600 tonnes
Australia's Talison produces 28,200 tonnes
Rockwood Holdings' Chemetall produces 22,500 tonnes
US-based FMC at 16,600 tonnes
Total 2010 production was estimated at 120,000 tonnes.
