pydata/pandas — pull request #5583 by Jaydyou (2013-11-25 12:45:46+00:00)
Title: ENH: Excel writer takes locale setting for date and datetime into account

Based on the locale setting the date and datetime values are formatted in
excel exports. Moreover the this behaviour can be overruled by keyword
arguments. Old behavior can be enforced by
ExcelWriter(file, date_format='YYYY-MM-DD', datetime_format='YYYY-MM-DD HH:MM:SS')