Este é um problema bem conhecido em salvar arquivos CSV no Excel, e não acredito que seja possível resolvê-lo diretamente. No entanto, um addon como este (inclui a origem) pode ser usado para contornar o problema.
How does it work?
As Excel can handle Unicode text (*.txt) files perfectly well, I’m relying on that to make this Addin work. On save, this Addin will be calling Excel’s SaveAs method to create a temporary Unicode Text file. It will then overwrite the original file by replacing all Tabs with comma and reload it. As it is a CSV file, Excel doesn’t preserve any column width adjustments or last active cell. Currently this Addin will reset the last active cell, and I think it should be pretty straightforward to reset column widths as well, if you wish to do so.