Batteries Batteries Batteries store chemical energy and Chemical Energy in to Electrical Energy. Anatomy of a Battery • The internal workings of a battery are typically housed within a metal or plastic case. Inside this case are a cathode, which connects to the positive terminal, and an anode, which connects to the negative terminal. These components, more generally known as electrodes. • A separator creates a barrier between the cathode and anode, preventing the electrodes from touching while allowing electrical charge to flow freely between them…. • Batteries are used in many applications, Automobile Industry, Power sector & in other Industrial Applications. • In Automobiles energy from the battery is used to power accessories, lighting and other electrical systems when the engine is not running. To supply the ignition, fuel and starting systems with the necessary power to start the vehicle Anatomy of a Battery • The medium that allows the electric charge to flow between the cathode and anode is known as the electrolyte How do batteries work? • Batteries create an uneven level of electrons which causes the electrons to move from a high concentration to a low concentration… • This is also known as the voltage difference. • The reaction in the anode creates electrons, and the reaction in the cathode absorbs them. The net product is electricity. What are the different types of batteries? Two Major Type of Batteries. Wet-Cell & Dry-Cell Batteries. Modern batteries use a variety of chemicals to power their reactions. Some of the more common types of batteries are: • Zinc-carbon battery or standard carbon battery • Alkaline battery • Lithium battery • Lithium-ion battery • Lead-acid battery • Nickel-cadmium or NiCad battery Wet cell – Dry cell Batteries • Wet cell batteries contain a liquid electrolyte solution which consists of sulphuric acid and water. Also known as Vented/flooded acid batteries • Wet cells will produce 2.1 Volts each and 6 cells connected in series (+ - ) allows them to produce the 12.6 - (12) Volts used by the automobile. • The main concern for wet cell batteries in all applications is leaking sulfuric acid, as it is a dangerous corrosive that can damage what it contacts and can burn human tissue. • Dry cell batteries will only produce 1.5 Volts per cell and can be connected in series (to produce more voltage). Dry cell batteries are batteries, which the electrolytes are in form of moist paste. They also refer to electrical batteries, which the electrochemical cells converts stored chemical energy into electrical energy. Wet cell Batteries 5. Lead-acid battery: • This is the chemistry used in a typical car battery. The electrodes are usually made of lead dioxide and metallic lead, while the electrolyte is a sulfuric acid solution. The amount and size of plates in a battery cell, determine the capacity of the battery. • Example, • Automobiles Batteries. Dry cell Batteries 1. Zinc-carbon battery: • Zinc and carbon are used in all regular or standard AA, C and D dry-cell batteries. The electrodes are made of zinc and carbon, with a paste of acidic materials (ammonium chloride or zinc chloride) between them serving as the electrolyte. 2. Alkaline battery: • This chemistry is common in AA, C and D dry cell batteries. The cathode is composed of a manganese dioxide mixture, while the anode is a zinc powder. It gets its name from the potassium hydroxide electrolyte, which is an alkaline substance…… Dry cell Batteries 3. Lithium battery: • These batteries are used in cameras for the flash bulb. They are made with lithium, lithium-iodide and lead-iodide. They can supply surges of electricity for the flash. 4. Lithium-ion battery: • Lithium chemistry is often used in high-performance devices, such as cell phones, digital cameras and even electric cars. A variety of substances are used in lithium batteries, but a common combination is a lithium cobalt oxide cathode and a carbon anode. 5. Nickel-Cadmium(nicad) Batteries: • The nicad system requires 10 series cells to reach a potential of 12 VDC. Dry Cell Battery Selection and Sizing of Battery • The duty cycle imposed on the battery will depend on the DC system design and the load requirements. The duty cycle showing the battery loads in amperes and the lengths of time for which they must be supported will determine the sizing of the battery. Loads may be classified as continuous or noncontinuous. Selection and Sizing of Battery Continuous loads: Continuous loads are classified as steady-state loads. Continuous loads are energized throughout the duty cycle and are normally supplied by the battery charger. Examples of typical continuous loads are • Lighting • Indicating lights • Continuously energized coils and operating motors Selection and Sizing of Battery Non-continuous loads Non-continuous loads lasting 1 min or less are known as momentary loads or short-time loads. Examples of typical non-continuous loads are • Circuit breaker operations • Motor operated valves • Inrush currents of motors or other devices • Field flashing of generators or synchronous motors Maintenance and Care of Batteries for Long Life The monitoring and maintenance of batteries is very important from the point of view of service reliability. • Inspections: Periodic inspection can provide information on the battery conditions and its state of health. All inspections should be made under normal float conditions. Inspection should be made at least once a month and should include the following checks: • Float voltage at battery terminals • Charger output current and voltage • General appearance and cleanliness of the battery • Electrolyte levels, cracks in jars, and leakage of electrolyte • Evidence of corrosion at terminals, connectors, racks, or cabinets Wet & Dry Cell Merits & Demerits • Merits: • Merits: 1. Most economical among diff types of batteries. • These Cells have voltage ranging from 1.25V-1.50V 2. Robust- not much sensitive to temperature. • Small sized, Primary Cells are used in torches, radios, hearing aid devices, watches etc. • Demerits 1. Needs periodic maintenancetwice a month. 2. Emits corrosive fumes. 3. Needs special battery room with acid proof tilling. 4. Cannot be transported in charged condition, initial charging takes 55 to 90 hours. 5. Needs specially trained persons for handling due highly hazardous sulphuric acid. • Demerits • These cells does not have long life, because the Acidic NH4Cl corrodes the container even when the cells are not in use. WHAT NOT TO DO WITH BATTERIES The following is detrimental to the life span of a battery: • Incorrect charge voltage. • Too low a voltage means that the battery does not charge to 100% - the sulphate then hardens on the plates and the battery loses some of it capacity. Excessive voltage causes the batteries to generate excessive gas leading to water los and drying out. • Excessive discharging. • Discharging a battery further than its capacity greatly shortens its life span • Too many cycles, high charge voltage, excessive discharging and significant voltage ripple in the charge voltage caused by cheap chargers and alternators. • Charging without 3 step regulation and very high electrolyte temperatures. BATTERY TERMINOLOGY • VRLAB Flooded Valve Regulated Lead Acid Batteries • GEL Gelled Electrolyte Lead Acid Battery • AGM Advanced Glass Mat Battery • CCA Cold Cranking Amps -18°C terminal V ≥7.2V for 30 sec. • CA Cranking Amps 0°C terminal V ≥7.2V for 30 sec. • RC Reserve Capacity 25°C terminal V ≥ 10.5V 25A Load = time • AH 100Ah = 20 hrs @ 5A load terminal V ≥ 10.5V • Peukert Exponent (ⁿ) Charge factor indicating efficiency of a battery Flooded cell battery is 80%. Must be recharged 1.2 times the capacity to reach 100%. Dynamic. Lower the factor – more efficient. Lithium-Ion 1.05. • Cp=Iⁿt Battery capacity = Discharge Current ⁿ x Time hrs