python-xlsx | Create , read , and modify Excel .xlsx files

I have one giant csv file that contains a year worth intraday data of a stock, as it is too big to analyse, I would like to process the data beforehand.

I want to break it down into 12 excel files (12 months), each one would have 28-31 sheets/tabs/pages that contains that intraday data for that date. Hence I have prepared these excel files with names Stock-01, Stock-02 until Stock-12, they are empty at the moment, waiting for data to append by my python code.

I am using the code below after I use read_csv: