230 likes | 340 Views
Batteries. Physics. Power Cell. Device for storing chemical energy and then releasing it in the form of electricity when current is needed. Battery. More than one power cell working together. 9 V battery. Inside a 9 V are 6-1.5 V power cells connected in a row. Parts of a Power Cell.
E N D
Batteries Physics
Power Cell • Device for storing chemical energy and then releasing it in the form of electricity when current is needed
Battery • More than one power cell working together
9 V battery Inside a 9 V are 6-1.5 V power cells connected in a row.
Parts of a Power Cell 1. Anode • Metal • High affinity for oxygen • Draw oxygen from cathode to become oxidized
Parts of a Cell 2. Cathode • Metallic oxide • Lower affinity for oxygen • Becomes reduced when oxygen is taken
Parts of a Cell 3.Separator • Insulator • Keeps cathode separated from anode to control reaction
Parts of a Cell 4.Current Collector • Connected to anode and cathode • Good conductor 5.Electrolyte • Usually liquid (ionized water, acid/base) • “Domino Effect” of oxygen from cathode to anode
Operation of Power Cell • As anode becomes oxidized, an electron must be given up • Electron flows through anode’s current collector through circuit (outside of battery) as electrical current back to cathode’s current collector
Carbon-Zinc (C-Zn) • 1.5 volts • Works well if using 100 mA or less • Low capacity • 3 year shelf life
Alkaline • 1.5 V: lose voltage gradually • High Capacity (electrical energy) • Last longer • 5 year shelf-life • Better in high drain devices than C-Zn
Lithium • Started off as button cell • Anode: lithium • Cathode: magnesium dioxide • 3 V: Takes up less space with more voltage
Lithium • High Capacity • Low Drain Rate • Toxic: Special disposal • Light Weight
Button Cell • Anode: Zinc or Lithium • Cathode: Silver or Mercury Oxide • Compact • Large Life
Recharging Batteries • A current from an outside source is pushed through the cell in the opposite direction from the original current • Oxygen goes from anode to cathode
Nickel-Cadmium (Ni-Cd) • 1.2 Volts • Low capacity • Memory effect (Rechargeable) • If you re-charge the battery too soon, you lower its capacity
Nickel-Metal Hydride (NiMH) • 1.2 V • Best rechargeable battery • High Capacity • Good for high drainage devices
Lithium-Ion • 3.6 V • Slow-loss of charge (5% per month) • Best energy to weight ratio • No memory effect • Popular for portable electronics (cell phones, IPod)
Diode • Made of semi-conducting material • Only permits current to pass in one direction • L.E.D.: light emitting diode • Longer leg must be connected to positive side of circuit (cathode)