Know More about Primary Battery

A primary cell is the kind of battery where the electrochemical reaction is not reversible. The disposable battery is a very common type of example for the primary cell. The chemical reversion can’t be possible like the secondary cell. In primary cell, the chemical reaction can’t be restored to the initial position and capacity of the cell and the materials are all used up with the electrodes. Using rechargeable batteries can be beneficial when the batteries are not that expensive and can be used many times. If primary batteries are used in the hand held tools then it could really be a costly business because you will need to replace the high capacity battery after every few hours.

On the contrary, the primary battery can be useful when storage for a long period is required. The primary batteries are designed to have less self discharge rate than the rechargeable batteries. So, you can get the power saved for more time when the capacity is needed for the purposes. Some specific works that take small amount of current for a long time uses the primary battery other than the rechargeable battery. Device like the smoke detector uses the primary battery for functioning. It uses the primary cell because if it uses the rechargeable battery then the battery could exceed the load current and can limit the service only to a few days or weeks. Like, a flashlight is needed to work on when there is an emergency even if it was kept idle for a long time. Some reserve batteries are designed to have storage time of about 10 years or more without the loss of the capacity. This is achieved by using the battery components assembled at the time of use and keeping them separated at other times. Such applications may be expensive but they are useful when required.

When in use the primary battery is polarized. This means the hydrogen accumulation at the cathode. Accumulation of cathode reduces the cell effectiveness. As a result it is important to remove the hydrogen. For removing this accumulation a depolarizer is used. This can be electrochemical, chemical or mechanical. However, there were attempts to make the simple self-depolarizing by making the surface cooper plates rough to facilitate the detachment of hydrogen. But there was little success here. Chemical depolarizing includes an oxidizing agent to oxidize and make the hydrogen turned into water. In chemical depolarizing manganese dioxide or nitric acid were used to oxidize the hydrogen. However, the hydrogen is exchanged to a metal such as silver or copper in electrochemical depolarization.

Now, let us know what anode and cathode are. The plate that carries usually the carbon terminal or the positive terminal in general is known as cathode. The plate that normally carries the negative terminal or the zinc in most time is known as anode. The terminologies are reversed as they are used in the electrolytic cell. The reason for it is that these are related to the electric current and not to the external circuit. Inside the cell the anode accepts the electrons from the electrolyte and acts as the electrode where the chemical oxidization occurs. The cathode on the other hand donates the electrons to the electrolyte and acts where the chemical reduction occurs. Outside the cell, the anode becomes negatively charged and becomes positively charged. So, anode is marked with the ‘’-‘’ terminal and cathode is termed as ‘’+’’ outside the cell.

Also Read: Dummies guide for Car Battery