Cells And Batteries 030103b Flashcards
A device that changes chemical energy into electrical energy is called?
A cell.
What is the main difference between a primary cell and a secondary cell?
Primary cells are non-rechargeable
Secondary cells are rechargeable.
What does a basic cell consist of?
Electrodes that are immersed in an electrolyte within a glass, metal or plastic container.
What effects the voltage produced by a cell?
Type of materials used for the electrodes and the type of electrolyte.
What two basic factors affect the capacity of a cell?
Objective 1 Page 3
The area and mass of the electrodes.
What are the two basic types of cells?
Objective 1 Page 2
Primary
Secondary.
Why is the Leclanche cell referred to as a dry cell?
Objective 2 Page 6
The electrolyte is a paste made of zinc chloride and ammonium chloride instead of a liquid.
What type of cell is a lead-acid cell?
Objecive 3 Page 9
Secondary
What are the three main types of lead-acid batteries?
Objective 3 Page 9
Flooded Cell
Gelled Electrolyte Cell
Absorptive Glass Mat (AGM) Cell
What type of lead-acid battery is the most common?
Objective 3 Page 9
Flooded Cell
What is the main difference between flooded cell and other lead-acid batteries?
Objective 3 Page 9
The electrolyte is liquid.
What type of lead-acid battery is used extensively as an automotive battery?
Objective 3 Page 9
Flooded cell.
What is a hydrometer for?
Objective 3 Page 10
Is an instrument used for measuring density of liquids. Can be used to test the gravity in batteries.
What is the open circuit voltage in a fully charged lead-acid cell?
Objective 3 Page 11
2.1 V per cell.
What terminal voltage should lead-acid batteries not be allowed to drop below to avoid permanent damage?
Objective 3 Page 11
1.75 V per cell.
What type of batteries can Gelled electrolyte cell and Absorptive Glass Mat (AGM) cell batteries referred to as?
Objective 3 Page 13
Valve-regulated lead-acid (VRLA)
They have one way valves that release gas pressure if the battery is recharged incorrectly.
The electrolyte used in a lead-acid cell is a dilute solution of what?
Objective 3 Page 10
Sulphuric Acid.
In a fully charged lead-acid cell, what is the specific gravity of the electrolyte?
Objective 3 Page 11
Between 1.25 and 1.28
What are the three advantages of using a gelled electrolyte battery instead of a lead-acid battery?
Objective 3 Page 12
Maintenance Free
Does not spill or leak (Corrosion Resistant)
Has no hazardous gas accumulations.
What is the open circuit voltage of a Ni-Cad cell?
Objective 4 Page 15
1.2V per cell.
How many cells does a 12 V Ni-Cad battery have?
Objective 4 Page 15
10 cells.
What are the 7 advantages of using a Ni-Cad battery over a lead-acid battery?
Objective 4 Page 15
Higher energy to weight ratio.
Lower internal resistance.
Faster recharge rates.
Longer storage life.
Operate reliably at higher or lower temperatures.
Capable of complete discharge/recharge.
Vented type rarely need water added.
What are some common applications for Ni-Cad batteries?
Objective 4 Page 16
Rechargeable tools, laptop computers and cameras.
Uninterruptible Power Supply (UPS) and emergency lighting.
Energy storage devices.
Utility Backup Power.
How much voltage can a lithium battery produce?
Objective 5 Page 18
3 to 3.7 V
What are some advantages of lithium batteries?
Objective 5 Page 20
Very lightweight.
Very high energy density.
Hold their charge. Loses only about 5% per month.
No memory. Can recharge at any time.
Can be charged and discharged hundreds of times.
What are some disadvantages of lithium batteries?
Objective 5 Page 21
Only last 2-3 years from date of manufacture.
Very sensitive to high temperatures.
Complete discharge destroys it.
Must be monitored by an on-board computer.
Can burst into flame when they fail.
Expensive.
What must be done to recharge a cell or battery?
Objective 6 Page 23
A voltage must be applied to have current flow in the reverse direction.
Why should cells have the same current when they are being recharged?
Objective 6 Page 24
To avoid cells from being overcharged.
What can happen if the cell temperature becomes excessively high during charging?
Objective 6 Page 23
Plate structure may be damaged and excessive gassing occurs.
What can happen if a fully charged battery is connected in parallel with a dead battery?
Objective 6 Page 24
Excessive gassing can occur and cause one battery to explode.
What do discharged lead-acid batteries tend to freeze in cold weather?
Objective 6 Page 24
The electrolyte solution dilutes and becomes more like water.
What kind of gas is produced when charging batteries?
Objective 6 Page 24
Hydrogen gas.
What does an ampere-hour rating (A*h) indicate?
Objective 7 Page 26
Total energy capacity of a battery. Current multiplied by time.
What percentage must the terminal voltage not fall below at the end of the ampere-hour rating time?
Objective 7 Page 26
91%
How long must a battery be able to provide power to the lights for?
Objective 7 Page 26
At least 30 mins.
What does the cranking amps (CA) rating indicate?
Objective 7 Page 26
Indicates the current that can be drawn from a fully charged battery for 30 secs at a temp of 0℃ without cell voltage falling below 1.2 V per cell.
What does the cold cranking amps (CCA) rating indicate?
Objective 7 Page 26
Indicates the current that can be drawn from a fully charged battery for 30 secs at a temp of 0°F without cell voltage falling below 1.2 V per cell.
What does the reserve capacity rating indicate and what is it quoted in?
Objective 7 Page 27
Indicates the number of minutes a fully charged lead-acid battery can maintain 25A at 25℃ before the voltage drops below 1.75 V per cell.
Quoted in minutes.
What unit of measurement is used when the cold cranking performance rating is given?
Objective 7 Page 26
Amperes.
Is internal resistance considered to be in series or in parallel with the cell?
Objective 8 Page 29
In series.
How do you calculate the volt drop of the internal resistance of a cell?
Objective 8 Page 29
The difference between the open circuit terminal voltage and the voltage under load conditions.
Vno load - Vwith load = Vdrop due to internal resistance.
