Week 8 - Type of battery

In Automobile manufacturers, it has identified four types of rechargeable battery as suitable for electric car to use. Those types are lead-acid batteries, zebra batteries, nickel metal hydride (NiMH) batteries, and lithium-ion (Li-ion) batteries.

 

Zebra batteries

The sodium or "zebra" battery uses molten chloroaluminate (NaAlCl4) sodium as the electrolyte. This chemistry is also occasionally referred to as "hot salt". A relatively mature technology, the Zebra battery boasts an energy density of 120h/kg and reasonable series resistance. Since the battery must be heated for use, cold weather doesn't strongly affect its operation except for in increasing heating costs. They have been used in several EVs. Zebras can last for a few thousand charge cycles and are nontoxic. The downsides to the Zebra battery include poor power density (<300 W/kg) and the requirement of having to heat the electrolyte to about 270 °C (520 °F), which wastes some energy and presents difficulties in long-term storage of charge. Zebra batteries have been used in the “Modec” vehicle (UK electric vehicle) commercial vehicle since it entered production in 2006.

                                       Figure 1: Example for Zebra battery

Nickel metal hydride (Ni-MH) batteries

Nickel metal hydride batteries came into commercial use in the late 1980s. They have a high energy density -- that is, a great deal of energy can be packed into a relatively small battery -- and don't contain any toxic metals, so they're easy to recycle. Currently, more than 2 million hybrid cars worldwide are running with Ni-MH batteries, such as Prius, Lexus (Toyota), Civic, Insight (Honda), Fusion (Ford), and others. Many of these batteries are manufactured by PEVE (Panasonic) and Sanyo. In the EU and due to the Battery Directive, Nickel–metal hydride batteries have replaced Ni–Cd batteries for portable use by consumers.

Lithium-ion (Li-ion) batteries  

Lithium-ion batteries, which came into commercial use in the early 1990s, have a very high energy density and are less likely than most batteries to lose their charge when not being used a property called self discharge. Because of their light weight and low maintenance requirements, lithium-ion batteries are widely used in electronic devices such as laptop computers. Some experts believe that lithium-ion batteries are about as close as science has yet come to developing a perfect rechargeable battery, and this type of battery is the best candidate for powering the electric cars of the near future. A variation on lithium-ion batteries, called lithium-ion polymer batteries, may also prove valuable to the future of electric vehicle (EV). These batteries may eventually cost less to build than lithium-ion batteries; however, at the present time, lithium-ion polymer batteries are prohibitively expensive.

                                         Figure 2: Example for Li-ion battery