Maximum number of rows of CSV data in excel sheet
CSV files have no limit of rows you can add to them. Excel won't hold more that the 1 million lines of data if you import a CSV file having more lines.
Excel will actually ask you whether you want to proceed when importing more than 1 million data rows. It suggests to import the remaining data by using the text import wizard again - you will need to set the appropriate line offset.
In my memory, excel (versions >= 2007) limits the power 2 of 20: 1.048.576 lines.
Csv is over to this boundary, like ordinary text file. So you will be care of the transfer between two formats.