#!/usr/bin/perl

use strict;
use warnings;
use Win32::OLE;

my $file = 'C:\voller\pfad\zu\Mappe1.xls';

my $excel    = Win32::OLE->new('Excel.Application','Quit') or die $!;
my $workbook = $excel->Workbooks->Open($file);
my $sheet    = $workbook->Worksheets(1);

$sheet->Range("b1")->{Value} = "Neuer Wert";

$excel->Save();