after 5 years would the permanent residence get approved automatic
The way the EU regulations, that came into force on 30.04.06, are drafted is that PR status is attained automatically, and without application, after 5 years exercising EU Treaty Rights in the UK.
Accordingly any application made on form EEA4 is effectively only asking for confirmation of that PR status. It is not actually granting anything that the person does not already possess.
In other words, it is not compulsory to make the EEA4 application. However for a non-EEA person such as yourself, it is actually quite handy to get get official confirmation that PR status is held, so certainly do file the EEA4 application near the end of your 5-year period.