Inspect and Service Nickel-cadmium Batteries 2

Question 1

Is the electrolyte level of a nickel-cadmium battery lowest when the battery is fully charged or fully discharged?

Answer 1

Fully discharged

Question 2

What is a result of cell imbalance in a nickel-cadmium battery?

Answer 2

The low internal resistance allows current to flow between the unbalanced cells and generate heat.

Question 3

What is a thermal runaway?

Answer 3

The large current flow allowed by the low internal resistance causes the middle cells to produce more heat than they can dissipate. The heat further lowers the internal resistance so more current can flow; this continues until the battery destroys itself.

Question 4

How man thermal runaway be prevented?

Answer 4

By carefully monitoring the temperature of the middle cells and controlling the charging current to prevent an excess of current flowing into the battery.

Question 5

How is it possible to know when a nickel-cadmium battery is fully charged?

Answer 5

Completely discharge the battery and give it a constant-current charge to 140% of its ampere-hour capacity.

Question 6

What is used to neutralize spilled electrolyte from a nickle-cadmium battery?

Answer 6

A solution of boric acid and water.