Cells and Batteries Flashcards
What is the difference between a primary and a secondary cell?
A secondary cell can be recharged, while a primary cell cannot.
A “_____” is a device which changes chemical energy into electrical energy. A battery is a group of cells connected in …?
Cell.
Series.
What are the three basic components of a cell?
- An electrolyte
- Two dissimilar metal plates:
- A positive electrode (cathode)
- A negative electrode (anode)
What factors affect cell voltage?
The material of the electrodes and electrolyte.
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.
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.
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
What are three types of lead acid batteries?
- Flooded cell
- Gelled electrolyte cell
- Absorptive glass mat cell.
How would one test specific gravity?
With a hydrometer.
What is a positive temperature coefficient switch?
An automatic switch which will stop current if the cell overheats.
Which type of battery can store the most amount of electrical energy per weight, and how much?
Lithium @ 150 W•h/kg
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.
What is the minimum time a battery pack can run for, while supplying an emergency lighting system?
Half an hour.
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.
Is a battery’s voltage under load ever greater than it’s open terminal voltage?
No.
