$PHPExcel = new \PHPExcel();
$PHPExcel->getActiveSheet()->getStyle('A1')->getNumberFormat()->setFormatCode('@'); //将A1设置成文本 @
$PHPExcel->getActiveSheet()->getStyle('A')->getNumberFormat()->setFormatCode('@'); //将A列设置成文本 @
单元格类型具体查看 PHPEXCEL/Style/NumberFormat.php