<?php

date_default_timezone_set('Australia/Canberra');

$value = $objPHPExcel->getActiveSheet()->getCell('A1')->getValue();

define('MIN_DATES_DIFF', 25569);
define('SEC_IN_DAY', 86400);

function excel2Timestamp($excelDate)
{
  if($excelDate <= MIN_DATES_DIFF)
  {
     return 0;
  }

  return ($excelDate - MIN_DATES_DIFF) * SEC_IN_DAY;
}

echo $result = date('H:i:s d/m/Y', excel2Timestamp($value));

?>

//get the excel date value (if it's stored in the A1 cell)
$excelDate = $objPHPExcel->getActiveSheet()->getCell('A1')->getValue();
//converts from excel format to a datetime object
$date = PHPExcel_Shared_Date::ExcelToPHPObject($excelDate);
//format the date as you want.
$formatedDate = $date->format('m/d/Y');