Question

Describe a alkaline battery cell listing the material used in its manufacture

Containers are therefore of welded sheet steel which is then nickel plated, or moulded in high-impact polystyrene-Steel casings are preferred when batteries are subject to shock and vibration.

The active materials of positive and negative plates in each cell of a charged nickel-cadmium battery are nickel hydrate and cadmium, respectively.

The container is filled with strong alkaline electrolyte is a solution of potassium hydroxide in distilled water (with an addition of lithium).

Normally cell voltage for this battery is 1.2.V.

With reference to alkaline batteries used on ship

Sate each of the following.

Significance of the relative density reading of electrolyte.

When the electrolyte would normally be renewed

Reason why the voltage reading of this type of battery is not necessarily indicative of its condition.

The normal temperature range and safe temperature limit of battery

Effects of low and high temperature.

b)

1. If the specific gravity falls then the electrolyte should be replaced or topped up.

2. When specific gravity falls to 1.17 @ 20deg C the electrolyte should be renewed as strength of solution drops

3. True voltage can only be obtained when battery on full load.

A chemical reaction takes place on surface showing full voltage even when battery is discharged.

4. The maximum safe temperature is 50 deg C

Normal operating temperature are +15deg C to 25 deg C

5. High temperature

Less efficient charging

Increased self discharge

Loss of capacity.

Shorter life.

Increased evaporation.

Low temperature

Electrolyte freezing of discharge cell.

Output voltage of fully charged cell will drop

Charging voltage will have to be increased ‘decreased evaporation.