Batteries (PDF)

BATTERIES A battery is an electrochemical cell or series of cells that produces an electric current. In principle, any galvanic cell could be used as a battery. There are two basic types of batteries: primary and secondary. Primary batteries are single-use batteries because they cannot be recharged....

BATTERIES A battery is an electrochemical cell or series of cells that produces an electric current. In principle, any galvanic cell could be used as a battery. There are two basic types of batteries: primary and secondary. Primary batteries are single-use batteries because they cannot be recharged. Ex. Dry cell (Zinc-Carbon battery), Alkaline battery Secondary batteries are rechargeable. These are the types of batteries found in devices such as smartphones, electronic tablets, and automobiles. Ex. Nickel-Cadmium battery, Lithium ion battery, Lead acid battery ENGINEERING 1 10/14/2024 CHEMISTRY  The dry cell is a zinc- carbon battery. The Zn can serves as both a container and the -ve electrode. The +ve electrode is a rod made of carbon that is surrounded by a paste of MnO2, ZnCl2, NH4Cl, carbon powder, and a small amount of water. The reaction at the anode can be represented as the ordinary oxidation of zinc. ENGINEERING 2 10/14/2024 CHEMISTRY Alkaline batteries were developed in the 1950s partly to address some of the performance issues with zinc–carbon dry cells. They are manufactured to be exact replacements for zinc-carbon dry cells. As their name suggests, these types of batteries use alkaline electrolytes, often ENGINEERING potassium hydroxide. 3 10/14/2024 CHEMISTRY Lithium ion batteries are among the most popular rechargeable batteries and are used in many portable electronic devices. The battery voltage is about 3.7 V. Lithium batteries are popular because they can provide a large amount current, are lighter than comparable batteries of other types, produce a nearly constant voltage as they discharge, and slowly lose their charge when stored. 4  Li ion Battery: An ideal Li ion battery will have High capacity High Energy Density Low weight, volume Low cost Excellent safety:- non toxic materials, and safe operation High charge/discharge rates possible Long service life An example for secondary batteries a) Dry cell b) Lithium ion battery c) Alkaline battery SPECIALITY BATTERIES  Nickel metal hydride battery (NiMH or Ni–MH): is a type of rechargeable battery. The chemical reaction at the positive electrode is similar to that of the nickel-cadmium cell (NiCd), with both using (nickel oxide hydroxide NiOOH). However, the negative electrodes use a hydrogen-absorbing alloy instead of cadmium. A NiMH battery can have two to three times the capacity of an equivalent size NiCd, and its energy density can approach that of a lithium-ion battery. 10  Torpedo Battery – The Silver Oxide Battery System Cathode/Anode/Electrolyte: Silver Oxide/Zinc/Aqueous Potassium Hydroxide Applications: Torpedoes, aquatic mines, swimmer aids, deep submersibles, underwater rescue vessels, various antisubmarine warfare applications. Distinguishing Characteristics: High energy per unit weight and volume. High discharge-rate capability. Moderate charge-rate capability. Good charge retention. Flat discharge voltage curve. Low maintenance. Low self-discharge. Safe 11  Reactions of Nickel Metal Hydride Battery Nickel oxy hydroxide, NiO(OH), is formed: Ni(OH)2 + OH− ⇌ NiO(OH) + H2O + e− The negative electrode reaction occurring in a NiMH cell is H2O + M + e− ⇌ OH− + MH Reactions of Silver oxide zinc Battery  Supercapacitor (SC) or Ultracapacitor It is a high-capacity capacitor with a capacitance value much higher than other capacitors, but with lower voltage limits, that bridges the gap between electrolytic capacitors and rechargeable batteries. It typically stores 10 to 100 times more energy per unit volume or mass than electrolytic capacitors, can accept and deliver charge much faster than batteries, and tolerates many more charge and discharge cycles than rechargeable batteries. Applications automobiles, buses, trains, cranes and elevators, where they are used for regenerative braking, short-term energy storage, or burst- mode power delivery. Smaller units are used as power backup for static random-access memory (SRAM). 14  FUEL CELL It is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from metals and their ions or oxides that are commonly already present in the battery, except in flow batteries. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied. 15  Generates electric power using a fuel and an oxidant.  Unlike a battery, chemicals are not stored in the fuel cell; they must be replenished.  Possible fuel sources: hydrogen, alcohols, hydrocarbons, gasoline.  Possible oxidants: oxygen, chlorine, chlorine dioxide.  Refueling of an internal combustion engine, efficient and quiet like a battery. 18 Direct methanol-O2 fuel cells or DMFCs  subcategory of proton-exchange fuel cells in which methanol is used as the fuel. Their main advantage is the ease of transport of methanol, an energy-dense yet reasonably stable liquid at all environmental conditions. 19 Electric Vehicle Batteries  An electric vehicle battery (EVB) or traction battery can be either a primary (e.g. metal-air) battery or a secondary Electric Vehicles (BEVs). battery rechargeable battery used for propulsion of battery.  Safe High Power High Capacity Small and Light Large Format Long Life Low Overall Cost  Nickel-metal Zebra or Lead-acid Sodium Battery hydride  The traditional lithium-ion chemistry involves a lithium cobalt oxide cathode and a graphite anode. This yields cells with an impressive 200+ Wh /kg energy density and good power density. 80 to 90% charge/discharge efficiency. Silicon nanowires, silicon nanoparticles, and tin nanoparticles promise several times the energy density in the anode.  Charging time is limited primarily by the capacity of the grid connection. Most batteries do not accept charge at greater than their charge rate ("1C"), because high charge rate has adverse effect on the discharge capacities of batteries. The charging power can be connected to the car in two ways : Conductive coupling Inductive charging  The first is simple as the mains lead into a weather proof socket through special high capacity cables with connectors to protect the user from high voltages. The second approach is that a special 'paddle' is inserted into a slot on the car. The paddle is one winding of a transformer, while the other is built into the car. When the paddle is inserted it completes a magnetic circuit which provides power to the battery pack.  The advantage of the inductive approach is that there is no possibility of electrocution as there are no exposed conductors. Although interlocks, special connectors and ground fault detectors can make conductive coupling nearly as safe. Inductive charging can also reduce vehicle weight, by moving more charging component off board.  New lithium-ion battery- equipped EVs provide 320–480 km (200–300 mi) of range per charge. Lithium is also less expensive than nickel. Car developed by NISSAN in 2001. Give the advantages of electric vehicle.