THE BEECHMONT CREST AUTOMOTIVE LEARNING ZONE
B a t t e r y B a s i c s
1.
Battery Basics: Ignition System
The battery is part of the ignition system.
-The ignition (key) releases a charge from the battery. Current from the battery flows to the ignition coil.
-The ignition coil amplifies the battery voltage, producing a very high-voltage surge. (20,000 to 40,000 volts)
-The high voltage surge flows to the distributor. The distributor channels this voltage to the spark plugs via the ignition wires.
Note: Many modern ignition systems do not have a distributor (distributorless ignition system = DIS).)
-Each spark plug ignites compressed fuel and air in the engine cylinder.-After the car is running, the alternator provides electrical power to the vehicle. The alternator also recharges the battery.
2.
Battery Basics: Basic Facts
- Most automotive batteries have a 12-volt charge (actually around 12.6 volts).
-Modern automotive batteries are “lead-acid” batteries: Positively charged lead dioxide (PbO2), and negative plates composed of straight lead (Pb), submerged in an ionized bath of sulfuric acid (H2SO4) diluted with water.
-Most batteries contain six connected cells, each of which produces 2 volts.
3.
Battery Charge/Transfer Reaction
-Power produced in cells (two electronically charged plates).
-One plate is positively charged (the anode), the other is negatively charged (the cathode).
- Charge-transfer reaction:
Electrons are exchanged between the anode (+) and cathode (-) via the electrolyte solution. These charge-transfer reactions occur on the surface of the plates, generating power.
4.
Battery Plate Group Arrangement
- Battery plates are arranged in “plate groups.”
- Each plate group consists of plates of the same polarity (+ or -). Plate groups are alternated within the battery (+ and -)
- There are non-conductive separators which assure that plate groups of the same polarity don’t come into contact.
-The battery case is made from molded polypropylene.
