Cells and Batteries Flashcards Preview

Electrical Theory Period 1 SAIT-Alberta > Cells and Batteries > Flashcards

Flashcards in Cells and Batteries Deck (24)
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1

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

A secondary cell can be recharged, while a primary cell cannot.

2

A "_____" is a device which changes chemical energy into electrical energy. A battery is a group of cells connected in ...?

Cell.

Series.

3

What are the three basic components of a cell?

  • An electrolyte
  • Two dissimilar metal plates:
    • A positive electrode (cathode)
    • A negative electrode (anode)

4

What factors affect cell voltage?

The material of the electrodes and electrolyte.

5

How do plate mass and area affect a cell's current producing capacity?

  • Mass is proportional to the amount of total producable current.
  • Area is proportional to discharging speed.

6

Why would the measured voltage of a battery under load be less than it's open circuit voltage?

Because of the internal resistance in the battery.

7

What are the four types of primary cells?

What are their typical terminal voltages?

  • Leclanche carbon zinc (dry) cell. 1.5V
  • Mercuric oxide cell 1.35V
  • Lithium manganese cell 3.0V
  • Alkaline manganese cell 1.5V

8

What are three types of lead acid batteries?

  • Flooded cell
  • Gelled electrolyte cell
  • Absorptive glass mat cell.

9

How would one test specific gravity?

With a hydrometer.

10

What is a positive temperature coefficient switch?

An automatic switch which will stop current if the cell overheats.

11

Which type of battery can store the most amount of electrical energy per weight, and how much?

Lithium @ 150 W•h/kg

12

How is recharging a battery accomplished?

A voltage exceeding the cell voltage is applied in a way which reverses current through the battery, effectively reversing the chemical reaction.

13

What is the minimum time a battery pack can run for, while supplying an emergency lighting system?

Half an hour.

14

What is amp-hour rating?

The time which a battery can maintain a sufficient voltage (100%-91%) while supplying a specified current.

The total charge capacity of the battery.

15

Is a battery's voltage under load ever greater than it's open terminal voltage?

No.

16

What is reserve capacity rating?

Time, In Minutes to discharge the battery

  • @25Amps
  • @25°C.

17

What is referred to by "cranking amps"?

Conversely, what are "cold cranking amps"?

CA = Current that can be drawn for 30 seconds @0°C,

CCA = Current that can be drawn for 30 seconds @0°F.

18

At which terminal voltage per cell of a flooded cell lead acid battery should the battery be recharged?

What would the specific gravity of the electrolyte be at this voltage?

1.75 Volts.

 

1.210 s.g.

19

Which type of battery is most subject to freezing?

A flooded cell lead acid battery.

Because, when the battery is discharged sufficiently the electrolyte is mostly water.

20

What materials make up a Leclanche carbon zinc cell?

  • Carbon electrode
  • Zinc electrode
  • Ammonium chloride/zinc chloride paste electrolyte

21

What materials make up an alkaline manganese cell?

  • Zinc powdered metal electrode
  • Manganese dioxide and graphite carbon electrode
  • Potassium hydroxide and water electrolyte

22

What materials make up a lead acid cell?

What is it's nominal voltage?

  • Spongy metallic lead electrode
  • Lead diixide electrode
  • Sulfuric acid (64%) and water electrolyte

2.1 Volts.

23

What materials make up a nickel cadmium cell?

What is it's nominal voltage?

  • Nickel hydroxide electrode
  • Cadmium hydroxide electrode
  • Potassium hydroxide electrolyte.

1.2 Volts

24

What materials make up a lithium cell?

What is it's nominal voltage?

How is it typically constructed?

  • Lithium cobalt oxide electrode
  • Carbon electrode
  • Ether with lithium salts electrolyte.

1.5 - 3.0 Volts.

Thin sheets of metal (electrodes) spiralled together and separated by microperforated plastic to allow ion flow but no conduction. Rolled up and inserted into a metal canister. Then filled with the liquid electrolyte and sealed.