How can I define a name in Excel using Powershell?

I know how to reference existing names using the RANGE function but how can I create a new defined name using Powershell?

My specific case involves defining a name for a single cell with a workbook scope.  Just as if you were to right-click a cell in Excel and choose Define Name.

The closest I've gotten is the NAMES object for the workbook but when I "gm" that all I see is a method for delete - nothing for adding.

$xlsx  = "c:\Sample.xlsx"
$excel = new-object -comobject Excel.Application
$xlb = $excel.Workbooks.Open($xlsx)
$xlb.names | gm