6.1  Introduction     

• Definition: A battery is an energy storage device, which converts chemical energy directly to electrical energy.
  
  
• Non-Rechargeable: This is called a primary cell. Typical battery types being: Alkaline, carbon-zinc, certain lithium metal batteries, silver oxide and zinc air.
  
  
• Rechargeable: This is called a secondary cell. Typical types being: Lead-acid, lithium-ion, certain lithium metal batteries, nickel-cadmium and nickel-metal hydride.  

6.2  History

• 250 BC: The oldest known electrical cells date from this time and were used by the Sumerians, in what is now Iraq, possibly to electroplate objects or for medicinal purposes. They were 1.1volt “jar” cells.
  
  
• Late 1790s: Alessandro Volta (Italian) was the first to produce a “dry” cell battery when he used silver (+) and zinc (-) plates to produce electricity.  Note: The word “volt” was named after him.
  
  
• About 1866: Georges Leclanche (French) patented what became known the “wet” cell battery. He used crushed manganese dioxide/carbon (+) and a zinc rod (-). It was the forerunner of the widely used zinc carbon cell battery. 

6.3  Lead-Acid

• This type of battery is found in modern conventional cars and can be recharged about 30 times (charge cycles).
  
  
• When used in electric vehicles (EVs) they are known as deep-cycle batteries and can be recharged up to 800 times.
  
  
• When subjected to “fast-pulse charging” the recharge time reduces from several hours to about 15 minutes.
  
  
• Its main disadvantage is low energy/poor density.
  
  
• Electric vehicles (EV) that have used this type of battery include: Chrysler EPIC Van, Ford Ranger EV, GM EV1 (Gen 1), GM Pickup, Fiat Panda Elettra, Samsung SEV-IV, Volkswagen Golf City Stromer, Bombardier NEV, Corbin Sparrow, Solectria Force, AC Propulsion t-Zero (Gen 1), REVA, ZAP Zebra and Bertone Z.E.R. 

6.4  Nickel-Cadmium (NiCad)

• The main advantage of the NiCad battery is that it has a high energy density and consequently it can be smaller than most other batteries of the same power.
  
  
• It also requires little maintenance and has a long life. Cadmium is, however, very toxic.
  
  
• EVs that have used this type of battery include: Citroen Saxo Electrique, Renault Clio RT, Peugeot 106 electric, Ford Th!nk, PIVCO City Bee and Zytek Lotus Elise. 

6.5  Nickel-Metal-Hydride (NiMH)

• The NiMH battery is totally sealed and hence maintenance free. Unlike some others it can operate in temperatures ranging from -6.6 to 48.8ºC. It can also be recharged in about 15 minutes.
  
  
• This type of battery has about twice the energy storage of the standard lead-acid battery. Its main advantage being high power density and long life.
  
  
• EVs that have used this type of battery include: Solectria Sunrise, GM EV-1 ll, Toyota RAV4 EV, Honda EV Plus. 

6.6  Sodium-Sulphur (NaS)

• The NaS battery has nearly 4 times the energy/density of lead-acid batteries (a much smaller battery for the same power).
  
  
• Its main disadvantage is that it must be kept at 300 to 350ºC, requiring a built-in heater. Safety concerns have been raised.
  
  
• EVs that have used this type of battery include: Ford Ecostar. 

6.7  Lithium-Ion (Li-ion)

• The Li-ion battery has about: (1) 3 times the energy storage capacity of a lead-acid battery. (2) 1.5 times that of a NiMH battery.
  
  
• It is also much lighter than other batteries. A complex cell control system is, however, required to operate a vehicle powered by these batteries.
  
  
• EVs that have used this type of battery include: Nissan Prairie Joy EV, Nissan Altra, Nissan Hypermini, Mitsubishi MiEV, AC Propulsion t-Zero (Gen 2) and Ford E-Ka. 

6.8  Zinc-Air & Aluminium-Air

• In these batteries the zinc or aluminium reacts with atmospheric oxygen to produce electricity. The process literally consuming the battery’s metal plates.
  
  
• When the battery no longer functions effectively new plates are inserted and any waste metal removed.
  
  
• This type of battery has an energy/density 10 times that of a lead-acid battery.
  
  
• EVs that have used this type of battery include: BAT International Electrovan (Zinc-Air).