Batteries Flashcards
What is a redox reaction ?
The number of electrons that an atom can gain, lose or share when chemically bonding with another atom
Oxidation is what?
Loss of e-
What are the 2 types of galvanic or non-rechargeable cells?
The zinc carbon cell and the zinc manganese oxide cell
What is a primary cell?
Cell which must be rebuilt or discarded after use
What are secondary cells?
Cells and those which can be recharged
What is a lechlanche cell?
Made up of 2 dissimilar materials immersed in a chemical paste electrolyte
What do primary cells do?
Convert chemical energy into electrical energy, active chemicals are depleting during discharge
What are the main components of a primary cell
Brass cap Central carbon rod (cathode) Electrolyte Depolariser Zinc plate (anode)
What is the first law of electrolysis ?
The quantity of elements separated by passing an electric current through molten or dissolved salt is proportional to the quantity of electric charge passed through the circuit
How can a lead acid battery be recharged ?
Injecting a known quantity of electrical energy to reverse the chemical reaction
How are secondary batteries rated?
By their open circuit voltage and the quantity of electrical energy they can supply before they reach their end point (EPV)
What is nominal voltage ?
Cell/battery off load or open circuit voltage
What is sulphation?
Sulphur in a discharged state and this crystallises to a white deposit which is an impregnable barrier to the current flow
What are the 2 types of secondary cells?
Nickel cadmium cell
Lithium ion cell
