Electro chemical studies on lead acid batteries By  M.SUDHEERA (Team Leader) K.SIVA PRASADA RAO (Member) P.ROHINIKUMAR (Member) Regional Center: 1353 RVR & JC College of Engineering (A)  

Introduction On Batteries

Importance of Battery The primary energy is an essential part of our life in our society due to change in the financial status, change in life style, etc. The coal, oils, and fossil fuels have long been exploited as primary energy. So it is very necessary to utilize/convert the primary energy into useful form of energy to fulfill the needs of the society. The most comfortable way of storing energy is the “Battery”.

Battery History 1800 Voltaic pile: silver zinc 1836 Daniel cell: copper zinc 1859 Planté: rechargeable lead-acid cell 1868 Leclanché: carbon zinc wet cell 1888 Gassner: carbon zinc dry cell 1960s Alkaline, rechargeable NiCd 1970s Lithium, sealed lead acid 1990 Nickel metal hydride (NiMH) 1991 Lithium ion 1992 Rechargeable alkaline 1999 Lithium ion polymer

What is battery ? Battery is an electrochemical device that converts the chemical energy into electrical energy.  

Classification Of Battery Batteries are broadly classified into two categories based on the nature of chemical reactions, namely Primary batteries Secondary batteries Primary batteries are not rechargeable i.e., the internal chemical reaction can’t be restored to original form. Whereas secondary batteries are rechargeable and the chemical reactions are reversible, when it supply a external current to the load resistance of the cell or battery.

Electrochemical characteristics and applications of the primary batteries Type Anode Cathode Electrochemical reaction Cell Voltage (V) Typical Applications Zn-Cl Zinc Chloride Zn + Cl2 → Zn+2 + 2Cl- 2.12 Flash lights, remote controllers, clocks, transistor radios Zinc-Mn MnO2 Zn +2MnO2 → ZnO +Mn2O3 1.5 Digital cameras, clocks, calculators, photo flash units Zinc/air Ambient air Zn + (1/2) O2 → ZnO 1.65 Torches , radios, toys, electrical purpose Li-MnO2 Li Li + MnO2 → MnO2 (Li+) 3.5 Watches, Calculators digital cameras, etc. Silver Zinc Ag2O Zn + AgO + H2O → Zn(OH)2 +Ag 1.6 Calculators, pagers, hearing aids, watches

Electrochemical characteristics of secondary batteries Type Anode Cathode Electrochemical reaction Cell Voltage (V) Typical Applications Lead acid Pb PbO2 Pb + pbO2 +2H2SO4 → 2PbSO4+2H2O 2.1 UPS, Inverter, SLI, telecom, railways ATMs, etc. Ni-Cd Cd Ni Oxide Cd+ 2NiO(OH) → 2Ni( OH)2 + Cd(OH) 2 1.2-1.3 Torches, radios, toys, digital still cameras electrical purpose, etc. Li-ion Carbon LiCoO2 LiCoO2 + 6C → LiC6 + CoO2 3.7 All portable electronic gadgets like cameras, lap top computers, etc.

Trends on battery The demand for the battery market increases with increase of requirement automotive and industry as well. The global market for battery technology was estimated as $8.2 billion in 2009 and expected to increase to nearly $11 Billion by 2014 with a compound annual growth rate (CAGR) of 6%. The global market tends of automotive lead acid batteries are expected to reach $15.4 billions by 2015 mainly due to charged by sustained demand from automobile industry as well.

Global Large and Advanced Battery market projections, 2001-2014

The benefits of the secondary batteries are A secondary battery can never be removed too far from the charger Have lower total cost of use and environmental impact than disposable batteries. Have higher initial cost, but can be recharged very cheaply and used many times. Lower energy density than primary cells Have higher self discharge rates