What is a battery? Principle of operation.
The battery is an essential component of electric car. It serves for ensuring start of the engine. In addition, the battery is a supplier of electric energy in an onboard network of the car.
Typically, the battery consists of a container which is divided by partitions into cells. In these cells they are called banks there are several interconnected special units. 12-volt car battery has 6 of these cells. Each of these units contains a set of positive and negative electrodes. Between different-pole electrodes consisting of lead grids smeared with an active substance are installed separators made of non-conducting material.
When casting the battery in working condition inside the cans poured an electrolyte (a mixture of sulfuric acid and water) then it is loaded by means of the special charger. In the process of increasing the charge density of the electrolyte inside the battery there are certain chemical reactions as a result of which there is an energy accumulation.
The operating principle of the battery
The principle of operation of lead-acid batteries is based on electrochemical reactions of lead and lead dioxide in sulfuric acid medium.
The energy is formed as a result from lead oxidation by sulfuric acid to sulfate. The electrode from oxide of lead could be graphite with hydrogen allocation. Lead oxide is necessary only to prevent hydrogen allocation on electrode. Hydrogen reacts with oxygen of oxide and forms water, restoring oxide to the metal and perhaps provides an additional output of energy from the oxidation of hydrogen.
At the time of discharge there is a restoration of lead dioxide on the cathode and oxidation at the anode lead. At a charge there is the return reactions to which at the end of a charge reaction of water electrolysis is added being accompanied oxygen allocation on a positive electrode and hydrogen - on negative proceed. As a result it turns out that at the discharge of the battery sulfuric acid with simultaneous formation of water (and density of electrolyte falls) is spent and at a charge on the contrary, water is "consumed" for formation of sulfuric acid (density of electrolyte grows). At the end of a charge at some critical values of concentration of lead sulfate at electrodes process of water electrolysis starts prevailing. Thus on the cathode hydrogen on the anode – oxygen is emitted. At a charge you shouldn’t allow water electrolysis, otherwise it is necessary to add it.