Cells And Batteries 030103b

Question 1

A device that changes chemical energy into electrical energy is called?

Answer 1

A cell.

Question 2

What is the main difference between a primary cell and a secondary cell?

Answer 2

Primary cells are non-rechargeable
Secondary cells are rechargeable.

Question 3

What does a basic cell consist of?

Answer 3

Electrodes that are immersed in an electrolyte within a glass, metal or plastic container.

Question 4

What effects the voltage produced by a cell?

Answer 4

Type of materials used for the electrodes and the type of electrolyte.

Question 5

What two basic factors affect the capacity of a cell?

Objective 1 Page 3

Answer 5

The area and mass of the electrodes.

Question 6

What are the two basic types of cells?

Objective 1 Page 2

Answer 6

Primary

Secondary.

Question 7

Why is the Leclanche cell referred to as a dry cell?

Objective 2 Page 6

Answer 7

The electrolyte is a paste made of zinc chloride and ammonium chloride instead of a liquid.

Question 8

What type of cell is a lead-acid cell?

Objecive 3 Page 9

Answer 8

Secondary

Question 9

What are the three main types of lead-acid batteries?

Objective 3 Page 9

Answer 9

Flooded Cell

Gelled Electrolyte Cell

Absorptive Glass Mat (AGM) Cell

Question 10

What type of lead-acid battery is the most common?

Objective 3 Page 9

Answer 10

Flooded Cell

Question 11

What is the main difference between flooded cell and other lead-acid batteries?

Objective 3 Page 9

Answer 11

The electrolyte is liquid.

Question 12

What type of lead-acid battery is used extensively as an automotive battery?

Objective 3 Page 9

Answer 12

Flooded cell.

Question 13

What is a hydrometer for?

Objective 3 Page 10

Answer 13

Is an instrument used for measuring density of liquids. Can be used to test the gravity in batteries.

Question 14

What is the open circuit voltage in a fully charged lead-acid cell?

Objective 3 Page 11

Answer 14

2.1 V per cell.

Question 15

What terminal voltage should lead-acid batteries not be allowed to drop below to avoid permanent damage?

Objective 3 Page 11

Answer 15

1.75 V per cell.

Question 16

What type of batteries can Gelled electrolyte cell and Absorptive Glass Mat (AGM) cell batteries referred to as?

Objective 3 Page 13

Answer 16

Valve-regulated lead-acid (VRLA)

They have one way valves that release gas pressure if the battery is recharged incorrectly.

Question 17

The electrolyte used in a lead-acid cell is a dilute solution of what?

Objective 3 Page 10

Answer 17

Sulphuric Acid.

Question 18

In a fully charged lead-acid cell, what is the specific gravity of the electrolyte?

Objective 3 Page 11

Answer 18

Between 1.25 and 1.28

Question 19

What are the three advantages of using a gelled electrolyte battery instead of a lead-acid battery?

Objective 3 Page 12

Answer 19

Maintenance Free

Does not spill or leak (Corrosion Resistant)

Has no hazardous gas accumulations.

Question 20

What is the open circuit voltage of a Ni-Cad cell?

Objective 4 Page 15

Answer 20

1.2V per cell.

Question 21

How many cells does a 12 V Ni-Cad battery have?

Objective 4 Page 15

Answer 21

10 cells.

Question 22

What are the 7 advantages of using a Ni-Cad battery over a lead-acid battery?

Objective 4 Page 15

Answer 22

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.

Question 23

What are some common applications for Ni-Cad batteries?

Objective 4 Page 16

Answer 23

Rechargeable tools, laptop computers and cameras.

Uninterruptible Power Supply (UPS) and emergency lighting.

Energy storage devices.

Utility Backup Power.

Question 24

How much voltage can a lithium battery produce?

Objective 5 Page 18

Answer 24

3 to 3.7 V

Question 25

What are some **advantages** of lithium batteries? ## Footnote Objective 5 Page 20

Answer 25

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.

Question 26

What are some **disadvantages** of lithium batteries? ## Footnote Objective 5 Page 21

Answer 26

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.

Question 27

What must be done to recharge a cell or battery? ## Footnote Objective 6 Page 23

Answer 27

A voltage must be applied to have current flow in the reverse direction.

Question 28

Why should cells have the same current when they are being recharged? ## Footnote Objective 6 Page 24

Answer 28

To avoid cells from being overcharged.

Question 29

What can happen if the cell temperature becomes excessively high during charging? ## Footnote Objective 6 Page 23

Answer 29

Plate structure may be damaged and excessive gassing occurs.

Question 30

What can happen if a fully charged battery is connected in parallel with a dead battery? ## Footnote Objective 6 Page 24

Answer 30

Excessive gassing can occur and cause one battery to explode.

Question 31

What do discharged lead-acid batteries tend to freeze in cold weather? ## Footnote Objective 6 Page 24

Answer 31

The electrolyte solution dilutes and becomes more like water.

Question 32

What kind of gas is produced when charging batteries? ## Footnote Objective 6 Page 24

Answer 32

Hydrogen gas.

Question 33

What does an ampere-hour rating (A*h) indicate? ## Footnote Objective 7 Page 26

Answer 33

Total energy capacity of a battery. Current multiplied by time.

Question 34

What percentage must the terminal voltage not fall below at the end of the ampere-hour rating time? ## Footnote Objective 7 Page 26

Answer 34

91%

Question 35

How long must a battery be able to provide power to the lights for? ## Footnote Objective 7 Page 26

Answer 35

At least 30 mins.

Question 36

What does the cranking amps (CA) rating indicate? ## Footnote Objective 7 Page 26

Answer 36

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.

Question 37

What does the cold cranking amps (CCA) rating indicate? ## Footnote Objective 7 Page 26

Answer 37

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.

Question 38

What does the reserve capacity rating indicate and what is it quoted in? ## Footnote Objective 7 Page 27

Answer 38

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.

Question 39

What unit of measurement is used when the cold cranking performance rating is given? ## Footnote Objective 7 Page 26

Answer 39

Amperes.

Question 40

Is internal resistance considered to be in series or in parallel with the cell? ## Footnote Objective 8 Page 29

Answer 40

In series.

Question 41

How do you calculate the volt drop of the internal resistance of a cell? ## Footnote Objective 8 Page 29

Answer 41

The difference between the open circuit terminal voltage and the voltage under load conditions. Vno load - Vwith load = Vdrop due to internal resistance.