I don't think you can save a CATIA table as a csv.
I'm told you can convert a csv into a CATIA table, but it's made with no link.
But, if you create an Excel spreadsheet first, you can copy & paste it to a CATdrawing. And you can double-click on the table to re-open the spreadsheet and edit it.
Do you know of any available script for transferring BOM from CATProduct to Excel. My company has an specific ISO formatted .xls documents with designated location for information like: quantity, part number, nomenclature and material. I'm not a catia script guru but I know this should be possible to achieve through scripting.