from openpyxl import Workbook
from openpyxl.utils import get_column_letter

wb=Workbook()

dest_filename='empty_book.xlsx'

ws1=wb.active
ws1.title="rangenames"

for row in range(1,40):
    ws1.append(range(600))

ws2=wb.create_sheet(title="Pi")

ws2['F5']=3.14

ws3=wb.create_sheet(title="Data")
for row in range(10,20):
    for col in range(27,54):
        _=ws3.cell(column=col,row=row,value="{0}".format(get_column_letter(col)))
print(ws3['AA10'].value)

wb.save(filename=dest_filename)