use Win32::OLE qw(in with CP_UTF8);
Win32::OLE->Option(CP => CP_UTF8);
use Win32::OLE::Const 'Microsoft Excel';
use Win32::OLE::Variant;
$Win32::OLE::Warn = 3;                                
my $Excel = Win32::OLE->GetActiveObject('Excel.Application') || Win32::OLE->new('Excel.Application', 'Quit');  # get already active Excel
$Excel->{'Visible'} = 1;
my $Book = $Excel->Workbooks->Open('foo.xlsx'); 
my $Sheet = $Book->Worksheets(1); 
$Sheet->Range("B1:Q1")->Merge();
$Sheet->Range("B1:Q1")->{HorizontalAlignment} = 'xlCenter';