Hybrid cars are powered by electric motors aside from gas engines and these motors rely on batteries.Hybrid car batteries are produced in similar manner as conventional car batteries and have similar function as well.The only big difference is that hybrid car batteries are built larger so as to be capable of producing the large amount of power required.But compared to batteries of pure electric vehicles,hybrid car battery is smaller,since hybrid cars also use gasoline engines.To provide for the demands of hybrid cars,their batteries have different internal constructions and materials from the conventional ones.Hybrid car batteries may came in packs containing several modules,with each module containing rows of cells.In the 2009 Toyota Prius,the 201.6-V battery pack has 28 modules.
Honda hybrids are moving to use lithium batteries.Toyota,though it is acquiring interests in extraction of lithium,is sticking to its use of NiMH rather than lithium,which have higher cost.But it is predicted that lithium could be the key to making hybrids more affordable in the future.Hybrid cars burn less fuel, thus reducing pollution,but their improperly-disposed batteries have toxicity effects on the environment,which would just trade one problem for another.All types of batteries have their environmental risks.In terms of the materials batteries are primarily made of,lead is the most harmful,while lithium is the least.Nickel is at the middle.
Each module,often encased in stainless steel,contains 6 cells,thus the entire pack has 168 cells.The battery voltage is inverted to alternating current for the 650-V AC electric motor.When a pack malfunctions,it is likely that a module is defective,and the pack could be rebuilt by replacing the appropriate module.In any car,a rechargeable battery powers the starter motor,the lights,the ignition system of the engine and the accessories,and a 12-V lead-acid battery could provide the power needed.In a hybrid car,another rechargeable battery is used to run the motor that powers the wheels,which means that a more powerful,high-voltage battery is required.Lead-acid batteries are heavy and cannot deliver the required power in a small package.Most car manufacturers,therefore,for practical purposes,have turned to other types of rechargeable batteries.
Today,nickel-metal hydride (NiMH) batteries are installed in most hybrid cars – more than two million worldwide.The electrodes used in NiMH batteries are hydrogen-absorbing alloy for negative and nickel oxyhydroxide for positive.Toyota Prius,Honda Civic Hybrid and Honda Insight,among others,use NiMH batteries.Another type of battery is the lithium ion batteries,which have more power in smaller packages.A lithium ion battery consists of an anode,a cathode and electrolyte.The anode is carbon like graphite.The cathode is a layered oxide of lithium cobalt oxide,or a polyanion like lithium iron phosphate or a spinel such as lithium manganese oxide.Electrolyte is a non-aqueous organic carbonates containing complexes of lithium ions.
As one of 3.7V lithium battery products,3.6V rechargeable battery is assembled with top-quality 18650 lithium battery cells and special PCM. This battery is free from overcharge, over discharge, over current and short circuit.Product label has listed main parameters and notes to help user protect lithium battery better.Technical process of early ternary material limited rated voltage 3.6V,thus this battery is also called 3.6V lithium battery.Yet present rated voltage of 3.6V rechargeable battery has reached 3.7V.Note: 3.6V rechargeable battery possibly refers to ni-mh battery because voltage of three 1.2V Ni-MH battery cell in series is 3.6V.
But if cobalt is used in lithium batteries,then it would be a problem.Recycling technologies play an important role in these materials’ environmental impacts.Lead has a mature recycling technology,but thousands of metric tons of lead end up in landfills every year.Nickel full recycling is still a challenge,and nickel is considered a probable carcinogen.At present,a few million hybrid cars represent just a fraction of the 700 million cars in operation worldwide.But as production and use of hybrids increase,the environmental impact of their batteries will proportionately be problematic and have to be addressed to as early as possible.
