capacity and efficiency of battery,What is the capacity of battery?

CAPACITY AND EFFICIENCY OF BATTERY

What is the capacity of battery?

ans: The battery capability represents the most quantity of energy which will be extracted from the battery beneath bound such that conditions. ... The energy keep during a battery, known as the battery capability, is measured in either watt-hours (Wh), kilowatt-hours (kWh), or ampere-hours (Ahr).

What are the factors which affect the capacity of a battery?

Ans. Factor Affecting Capacity of a Lead Acid Battery:

1. Rate of Discharge: Higher the rate of discharge, smaller is the capacity.

2. Permissible Final Voltage per Cell : Lower is the final voltage on discharge, higher is the capacity.

3. Number of plates/elements : A 23 plates/element battery does have more capacity than that of a 19 plate/element and so on.

4. Amount of Active Material : Greater is the amount of active material on the plates, larger is the capacity.

5. Operating Temperature : Within given limits of operating temperature, a battery gives batter capacity in summer than in winter. If the operating temperature crosses 43°C, the battery can be permanently damaged.

6. Quantity of Electrolyte: If the level of electrolyte is not maintained properly, the capacity decreases.

7. Age of Battery: The capacity falls with the passage of working life of a battery.

8. Specific   Gravity of Electrolyte : A poor specific gravity reduces capacity of the battery.

 

In what terms the efficiency of battery is taken?

 Ans. The efficiency of battery is taken in two ways:

1. Quantity or ampere hour efficiency

 

 

2. Energy or Watt hour efficiency

 

 

Wh-efficiency is always less than Ah-efficiency because p.d. during discharge is less than during charge.

               Normally Ah-efficiency of the lead acid cell lies between 90 to 95%while Wh-efficiency varies between 70 to 80%.

 

What do you mean by the following in the battery?

1. Sulphation

2. Buckling of plates

3. Sedimentation.

Ans.  1. Sulphation: The effect is usually noticed by a whitish colour on plates and is caused by over-charging over-discharging or keeping the discharged battery for a long time.

              Carbonate of soda added to the electrolyte has a beneficial effect in preventing sulphation defect, or the best way is trickling charge i.e., charging the battery at a low mie for a long time.

2. Buckling of plates: This is trouble in which plates bend. It is due to overcharge and over discharge. The battery having buckling plate must be replaced for a good service.

3. Sedimentation : Due to the charging and discharging and due to continuous use, the small parts from the active material i.e., +ve plate breaks and keeps on depositing at the bottom. After some time this deposited material starts short-circuiting. Replace the electrolyte and clean bottom surface to avoid short-circuiting due to sediments deposited at the bottom.

 

Describe Alkaline Cells.

Ans. Alkaline Cells: These are of two types:

1. Nickel iron type known as Edison cell.

2. Nickel cadmium cell known as Junger cell.

Edison Cell (Nickel iron type) : The material used in the cell are :

(a) Nickel oxide on the positive plate.

(b) Iron oxide on the negative plate.

(C) The electrolyte is 20% solution of caustic potash (KOH) along with some quantity (1%) of lithium hydroxide (LiOH) whose effect is to increase the capacity of the cell.

 

Construction: The positive plate consists of a number of tubes made of perforated steel ribbon, wound spirally and held together by steel rings. The tubes are nickel-plated. The active material consisting of nickel hydroxide Ni(OH). and flakes of metallic nickel are packed into the nickel-plated steel tubes in alternate layers. Flakes are added to increase the conductivity of the electrolyte. The tubes are then clamped in a nickel-plated steel frame.

             The negative plate is made from finely perforated nickelled steel strip stamped into pockets. The pockets are filled with powdered iron oxide. A little mercury is added to improve conductivity.

             The plates are separated from one another by hard rubber strips and are held in a nickel-plated container. The normal density of the electrolyte is 1.22 and this falls to

about 1.19 which is compensated with the addition of fresh electrolyte of density 1.25.

 

Charging: When a current is passed KOH molecules dissociate into K and (OH) ions. The (OH) ions go to the positive plate, K ions to the negative plate.

Thus the +ve plate is changed into Ni(OH), whereas the-ve plate is changed into Fe. Actually there is no change in the composition of the electrolyte and its specific gravity remains constant during charge and discharge.

 

Discharging : Reverse phenomenon takes place on discharging

Hence the plates return to their original conditions. During discharge the electrolyte again remains in the same condition - a great advantage over lead acid cell.

Characteristics of Nickel Iron Cell

 (i) Fully charged cell has e.m.f. of 1.4V. It decreases rapidly to 1.3 V and then very slowly to 1.1 V on discharge.

(ii) It has good mechanical strength due to steel plates.

(iii) The cell can withstand heavy charge and discharge currents.

(iv) There is no harm to leave it in discharged condition for a long period.

(v) Internal resistance is large and so efficiency is lower than the lead acid cell.

(vi) With increase in temperature, e.m.f. decreases slightly but the capacity increases appreciably.

(vii) It is superior to lead acid cell in mechanical strength, durability and robustness.

 

Nickel Cadmium Cell: The positive plate is built up from a number of steel tube made of perforated steel and the same electrolyte. However, the negative plate is of cadmium unlike the Edison Cell. The use of cadmium reduces the internal resistance of the cell.

 

SEALED MAINTENANCE FREE BATTERY

 A sealed battery or maintenance free battery, may be a variety of lead-acid reversible battery. because of their construction, they will be mounted in any orientation, and don't need constant maintenance. they're wide utilized in massive moveable electrical devices, off-grid power systems and similar roles, wherever massive amounts of storage ar required at a lower value than alternative low maintenance technologies like lithium-ion.

There ar 2 primary varieties of sealed batteries, gel cells and AGM. Gel cells add oxide mud to the solution, forming a thick putty-like gel. These ar noted as "silicone batteries". AGM, short for "absorbed glass mat", batteries feature fiber glass mesh between the battery plates that serves to contain the solution. each styles supply blessings and downsides compared to traditional batteries, still as one another

Its principle is that lead-acid cells encompass 2 plates of lead, that function electrodes, suspended in diluted oil of vitriol, that is then the solution. In standard lead-acid cells, the diluted acid is in liquid kind.

Advantages:

1. This battery is mounted in any position.

2. area ventilation needs ar less.

3. No acid fume is emitted throughout traditional operation.

4. Volume of free electrolytes that would be discharged on injury is incredibly less.

5. No have to be compelled to check the extent of water or electrolytes.

 6. This battery recharges abundant faster than others.

 

Disadvantages:

1. These batteries ar reliable.

2. These batteries have shorter recharge time.

3. These cannot tolerate overcharging.

4. These batteries have shorter helpful life.

5. These batteries discharge less gas gas.

6. These is utilized in any orientation.

 

SOLAR BATTERY SYSTEM

A electrical device system is formed of a pervious mesh solar array from metallic element gauze, a versatile material upon that vertical rods of titania like blades of grass ar grew. Air passes freely through the gauze whereas the rods capture daylight.

Normally, connecting a electric cell to A battery would need the utilization of 4 electrodes.

The mesh solar array forms the primary conductor. at a lower place a skinny sheet of porous carbon (the second electrode) and metal plate (the third electrode) is placed. Between the electrodes, sandwiched layers of solution to hold electrons back and forth.

During charging, light-weight hits the mesh solar array and creates electrons. within the battery, electrons ar concerned within the chemical decomposition of metal ions ar hold on within the battery as metal metal when capturing the electrons.

When the battery discharges, it with chemicals consumes gas from the air to re-form the metal peroxide.

An halide additive within the solution acts as a "shuttle" that carries electrons, and transports them between the battery conductor and therefore the mesh solar array. the utilization of the additive represents a definite approach on up the battery performance and potency.