A hybrid vehicle has at least two sources of power to propel the vehicle. The two most common combined power sources are internal combustion engines and electric motors. This then gives rise to hybrid electric vehicles. Other power sources that may be used for this power include hydrogen, liquid nitrogen, wind, and solar power. Auto manufacturers have over the last few years started investing in the research and development of hybrid cars and fully electric cars. This change in trend can be attributed to the soaring fossil fuel prices and the growing concern on pollution and environmental change (Pollit, 2008). The main challenge being faced by these auto giants is the difficulty in developing a battery system that can last longer between charges and one that takes the least time to charge. Whereas some companies have succeeded in developing long-life rechargeable batteries, these batteries take many hours to charge and therefore still pose a huge inconvenience to the users.
Common Battery Technologies
Some of the most common battery technologies in use today include VRLA, NiMH, Li-Ion, and NiZn.
VRLA (valve regulated lead acid) are rechargeable lead-acid batteries. These batteries are classified into two main categories; absorbent glass mat battery and gel battery. Although sometimes they are referred to as sealed lead-acid batteries, these batteries have a safety pressure relief valve. VRLA batteries do not spill their electrolyte even when inverted in contrast with vented batteries. They also use a lot fewer electrolytes and do not need regular topping because of their modified design. VRLA batteries are commonly used in telecommunication systems especially UPS systems due to their high rate capacity. Interest has been shown in trying to improve these batteries for use in hybrid vehicles (Linden & Reddy, 2002).
Li-ion (Lithium-ion batteries) batteries on the other hand are batteries that use lithium in their electrolyte. Lithium ions flow from the anode to the cathode in discharge and from the cathode to anode during charge. Like VRLA, lithium batteries are also rechargeable and have very high energy-to-weight ratios; a feature that makes them a favorite in portable electronics like mobile phones and laptop computers (Linden & Reddy, 2002).
Early Lithium batteries used an anode made of metallic lithium which posed a great threat to users in terms of safety and led to the development of an anode that contains lithium ions. John Goodenough’s research team later found a way by using graphite, and the Li-ion battery was born in 1981.
Current battery technologies that have been deemed viable for use in the hybrid era include not only Li-ion batteries but also others like Nickel Meta hydride batteries.
Li-ion batteries have had many advantages following their development over the past few years. They can easily be molded into a wide range of shapes which ensures suitability in use for various applications as they can be fitted into devices with limited space. Li-ion batteries have another advantage in that they have a much lower mass than their Nickel counterparts. This is particularly important in the hybrid car era as battery size and weight is given a lot of priority (Mierlo & Maggetto, 2007). Most batteries that are tested for use in hybrid cars are large and heavy; a lighter battery would be a great contribution to the hybrid car business. Lithium batteries do not suffer from the memory effect. This is my view is vital for the hybrid and electric car industry as it allows the battery to be recharged even if it is not yet fully depleted without compromising the battery quality. It makes it possible for Li-ion batteries to be recharged like refilling a gas tank. In addition to the above advantages, Li-ion batteries have the lowest self-discharge rates at an approximate value of 0.1% per month as compared to nickel Meta hydride batteries with about 1.25% (Linden & Reddy, 2002)
Despite their many advantages, Li-ion batteries have a poor life cycle because, with every recharge, lithium-ion transport is hindered by deposits in the electrolyte. Also, high temperatures reduce the capacity of the Li-ion batteries over time. This would be a major factor to be considered in hybrid and electric cars as it would affect the reliability of the cars over time (Nilsson & Johansson, 2001). The aspect of cost can also not be ignored because such a problem would mean replacing the costly batteries often. Additionally, Li-ion batteries have raised safety issues because of their susceptibly to explosions.
The nickel-meta hydride cell (NiMH) is another common type of battery currently underused and research. It is a secondary electrochemical cell that works by employing a hydrogen-absorbing cathode and a nickel oxyhydroxide anode. NiMH cells have very low internal resistance and this makes them suitable for high current drain applications; NiMH cells handle high current drain while maintaining their full capacity. Besides having a lower energy density than Li-ion batteries, NiMH cells also have a much longer shelf life. This is a very desirable quality especially for electric cars because these cars will have to endure many recharges over many years (Reuters, 2007)
The future of hybrid and all-electric vehicles/conclusion
Currently, battery technologies are being researched to find the most reliable, durable, and efficient battery. Li-ion batteries are being improved so they can transfer the relative reliability displayed in portable electronics to electric cars while displaying longevity in their life spans.
An interesting innovation in the hybrid era is the series hybrid. This uses one or more electric motors driven by a single-speed internal combustion engine. An electric generator is coupled to the single-speed engine instead of the drive wheels. This enables the generator to generate electricity that can be used to charge a battery or directly power the electric motor. Batteries and capacitors in addition to the generator provide any extra power if a lot of power and torque is desired. Capacitors employed in this system eliminate the need for batteries as the capacitor acts as the storage device
With the current research, the future looks bright for the electric car because several companies including General Motors and Toyota have succeeded in developing batteries that can solely power their cars for distances more than 40 miles (Andrews & DeVault, 2009).
I think researchers should pursue the quest of achieving all-electric cars. Other alternative power sources like solar and even nuclear power should however not be overlooked as they just might be the best solution for clean energy.
Moving away from fossil energy will have a positive impact on society because the matters of pollution and environmental degradation will be improved as is now demanded by many a society. Technological advancements shape how society operates because society, regardless of its beliefs, will always use whatever technology presents to it.
Newer battery technologies are bound to lead engineers to reconsider the traditional layout of a front-mounted combustion engine coupled to either a front-wheel drive train or a rear-wheel drive train because electrically powered cars might eliminate the need for complicated drive trains used for speed multiplication because then speed would be controlled electrically.
Emerging technologies in battery research show that electric vehicles will have a positive impact on the environment because there will be no carbon emissions that lead to environmental degradation. Batteries are clean energy sources and are sustainable.
List of References
Andrews, C & DeVault D 2009,’ Green Niche Market Development’, Journal of Industrial Ecology. Vol. 13, no. 2, pp. 326-345.
Linden, D & Reddy T 2002, Handbook Of Batteries 3rd Edition, McGraw-Hill, New York.
Mierlo, J & Maggetto, G 2007,’Fuel Cell or Battery: Electric Cars are the Future’, Fuel Cells. Vol. 7, no. 2, pp. 165-173.
Nilsson, J & Johansson B 2001,’ Cars and fuels for tomorrow: a comparative assessment’, Natural Resources Forum.Vol.25, no. 2, pp. 109-120.
Pollit , M 2008, ‘Hybrid advantage’, The Guardian , p.14.
Yahoo finance, Singapore, quoting Reuters, 2007, “Mitsubishi Heavy to make lithium ion car batteries”. Web.