How to append multiple sheets on a excel file(.xlsx format) in Powershell?

Currently I have a script in which I generate reports and save it in an .xlsx format. But my problem is when I try to generate a second report and onward, it overwrites the entire report instead of appending to it as a second sheet and onwards. Anyways Ill show you guys a very partial script.

$excel2 = New-Object -ComObject excel.application;
$excel2.visible=$false;
$serverInfoSheet= $excel2.Workbooks.Open("C:\Temp\Tasks[$i].csv"); # i is just a number starting from 1, I have the counter already in my full script
$serverInfoSheet.Activesheet.Cells.EntireColumn.Autofit();
$ServerInfosheet.SaveAs("C:\Temp\report.xlsx",51) 
$excel2.Quit()