Secondary Batteries (Lead acid battery) Video Lecture - NEET

let's have a discussion on working
principle of lead acid battery this is
very commonly used as storage battery or
secondary battery before going through
the working principle we should know
about materials used for lead acid
storage battery cells
the main active materials required to
construct a lead acid battery are led
peroxide sponge LED and dilute sulfuric
acid the positive plate of lead acid
battery is made of lead peroxide this is
dark brown hard and brittle substance
the negative plate of lead acid battery
is made of pure lead in soft sponge
condition dilute sulphuric acid used for
lead acid battery has ratio of water is
2 acid equal to 3 is to 1 the lead acid
storage battery is formed by dipping
lead peroxide plate and sponge lead
plate in dilute sulfuric acid a load is
connected externally between these
plates in diluted sulfuric acid the
molecules of acid split into positive
hydrogen ions and negative sulfate ions
the hydrogen ions will reach at lead
peroxide plate they receive electrons
from it and become hydrogen atom which
again attacked lead peroxide and form
lead oxide and water
this led oxide reacts with sulfuric acid
and forms lead sulfate and water
negative sulfate ions are moving freely
in the solution so some of them will
reach to pure LED plate where they give
their extra electrons and become radical
sulfate as the radical sulfate cannot
exist alone it will attack pure LED and
will form lead sulfate
as positive hydrogen ions take electrons
from lead peroxide plate and negative
sulfate ions give electrons to lead
plate there would be an inequality of
electrons between these two plates hence
there would be a flow of current through
the external load between these plates
for balancing this inequality of
electrons this process is called
discharging of lead acid battery now we
will disconnect the load and connect
lead sulfate covered lead peroxide plate
with positive terminal of an external DC
source and lead peroxide covered lead
plate with negative terminal of that DC
source during discharging the density of
sulfuric acid Falls but they're still
sulfuric acid exists in the solution
this sulfuric acid also remains as
positive hydrogen ions and negative
sulfate ions in the solution hydrogen
ions being positively charged moved to
the electrode connected with the
negative terminal of the DC source here
each hydrogen ion takes one electron
from that and becomes hydrogen atom
these hydrogen atoms then attack lead
sulfate and form lead and sulfuric acid
negative sulphate ions move towards the
electrode connected with the positive
terminal of DC source where they will
give up their extra electrons and become
radical sulfate this radical sulfate
reacts with lead sulfate of anode and
forms lead peroxide and sulfuric acid
hence by charging the lead acid storage
battery cell becomes ready for
discharging thank you