所以你有一个正确的想法，使用名称编辑列。我们只需要按行编辑每个值。谢天谢地，我们还可以得到column names，所以它应该工作，而不必手动输入所有列。我使用@Theo的建议，预先附加“`t”到单元格值，这解决了Excel以科学记数法显示值的问题。
希望这是一个很好的起点。在目前的状态下，它可能不是最有效的。

$path = "C:\Test\*.txt"
$files = Get-ChildItem $path | where { ! $_.PSIsContainer }
foreach ($file in $files){
    $newFileName = ($file.Fullname) -Replace ".txt",".csv"
    $csv = Import-Csv $file.FullName

    # get column names
    $columnNames = ($csv[0].psobject.Properties | select Name).Name

    # will have to work by row
    $rowNum = [int]0
    while ($rowNum -lt $csv.count){
        
        # on the row change value for each column
        foreach ($column in $columnNames) {
    
            
            $csv[$rowNum].$column = "`t" +  $csv[$rowNum].$column
        }
        
        $rowNum += 1
    }

    
    # was running into a bug with powershell on a mac so had to pipe $csv to export-csv instead of using -input-object
    $csv | Export-Csv -LiteralPath $newFileName -NoTypeInformation
    
}

继续我的评论：

• 要阻止Excel在打印数据时转换数值，您可以在其值前添加一个TAB字符。Excel将以文本形式读取该值
• 当使用Export-Csv保存更新的数据时，您可以附加开关-UseCulture，以便使用的delinmiter字符是从设置为本地ListSeparator字符的任何字符中选择的。Excel希望通过双击打开文件时，这样您就不必使用导入向导。（要查看系统中设置的字符，请使用(Get-Culture).TextInfo.ListSeparator）

$path = 'C:\Test'
$files = Get-ChildItem $path -File -Filter '*.txt'
foreach ($file in $files) {
    $data = Import-Csv -Path $file.FullName
    foreach ($row in $data) {
        # prepend a TAB character in front of the field you want Excel to 
        # treat as string as opposed to converting it to scientific value
        $row.acct = "`t{0}" -f $row.acct
        # you can do the same here for fields 'data_id', 'sec_acct' etc if needed
    }
    $newFile = [System.IO.Path]::ChangeExtension($file.Fullname,".csv")
    # now save the updated data. With -UseCulture you can simply
    # double-click the created csv file to open in Excel on any machine
    # that has the same locale setting for the ListSeparator
    $data | Export-Csv -Path $newFile -NoTypeInformation -UseCulture
}