Date and Datetime using PHPExcel function writes in excel as Text

I have a problem with PHPExcel function, this is my code:

<?php
# Load slim WP
define( 'WP_USE_THEMES', false );
require( './wp-load.php' );
# http://phpexcel.codeplex.com/
require_once dirname(__FILE__) . '/Classes/PHPExcel.php';
global $wpdb;
$query = "Select
  tsales_funnel.ID As ID,
  wp_users.display_name As Darijuma_vaditajs,
  tcportal_starpnieks.Cp_Name As Starpnieks,
  tcportal_stucture.Cp_Name As OWCA,
  n_products.Product_Nos As Produkts,
  tsales_funnel_mrecord.Product_type as Produkta_kods,
    tsales_funnel.Sanems_date as Saņēmšanas_datums,
  tsales_funnel_mrecord.Deadline As Deadline,
  n_sf_statusi.nosaukums_lv As Statuss,
  tsales_funnel_clients.Reg_nr As Klienta_Regnr,
  tfirmas_reg.name_in_quotes As Klients,
  tsales_funnel_mrecord.Faze_date as Faze_date,
  n_sf_fazes.nosaukums_lv As Faze,
  tsales_funnel_mrecord.Summa As Apdrošīnājuma_summa,
  tsales_funnel_mrecord.Vien_skaits As TRL_skaits,
  tsales_funnel_mrecord.Compensa_cena,
  tsales_funnel_mrecord.Tirgus_cena,
  wp_users02.display_name As Riska_parakstitajs,
  comm.Comment as Aizveršanas_komentārs
From
  tsales_funnel Left Join
  tsales_funnel_mrecord On tsales_funnel.ID = tsales_funnel_mrecord.Funnel_ID
  Left Join
  tcportal_starpnieks On tcportal_starpnieks.Cp_code = tsales_funnel.Starpnieks
  Left Join
  tcportal_stucture On tcportal_stucture.Cp_code = tsales_funnel.OWCA Left Join
  tsales_funnel_clients On tsales_funnel_clients.Funnel_ID = tsales_funnel.ID
  Left Join
  tfirmas_reg On tfirmas_reg.regcode = tsales_funnel_clients.Reg_nr Left Join
  wp_users On tsales_funnel.Darijuma_vaditajs = wp_users.user_login Left Join
  n_sf_statusi On n_sf_statusi.id = tsales_funnel.Statuss
  Left Join n_sf_fazes on tsales_funnel_mrecord.Product_faze = n_sf_fazes.id
   Left Join
  n_products On tsales_funnel_mrecord.Product_type = n_products.Product_Code
  Left Join
  (SELECT * FROM tsales_funnel_comments WHERE Comm_type = 4) as comm On tsales_funnel.ID = comm.Funnel_ID
  Left Join
  wp_users As wp_users02
    On wp_users02.user_login = tsales_funnel_mrecord.Risk_acceptance
WHERE 
tsales_funnel_clients.Tips_Galvenais = 1
";
$error = "Error: the query failed...
    <pre style='width:700px;word-wrap:break-word;white-space:normal;'>$query</pre>";
$result = $wpdb->get_results( $query, ARRAY_A ) or wp_die( $error );
$objPHPExcel = new PHPExcel(); 
$objPHPExcel->getProperties()
        ->setCreator("user")
            ->setLastModifiedBy("user")
        ->setTitle("Office 2007 XLSX Test Document")
        ->setSubject("Office 2007 XLSX Test Document")
        ->setDescription("Test document for Office 2007 XLSX, generated using PHP classes.")
        ->setKeywords("office 2007 openxml php")
        ->setCategory("Test result file");
// Set the active Excel worksheet to sheet 0
$objPHPExcel->setActiveSheetIndex(0); 
// Initialise the Excel row number
$rowCount = 0; 
// Sheet cells
$cell_definition = array(
    'A' => 'ID',
    'B' => 'Darijuma_vaditajs',
    'C' => 'Starpnieks',
    'D' => 'OWCA',
    'E' => 'Produkts',
    'F' => 'Produkta_kods',
    'G' => 'Saņēmšanas_datums',
    'H' => 'Deadline',
    'I' => 'Statuss',
    'J' => 'Klienta_Regnr',
    'K' => 'Klients',
    'L' => 'Faze_date',
    'M' => 'Faze',
    'N' => 'Apdrošīnājuma_summa',
    'O' => 'TRL_skaits',
    'P' => 'Compensa_cena',
    'Q' => 'Tirgus_cena',
    'R' => 'Riska_parakstitajs',
    'S' => 'Aizveršanas_komentārs'
);
// Build headers
foreach( $cell_definition as $column => $value )
    $objPHPExcel->getActiveSheet()->setCellValue( "{$column}1", $value ); 
// Build cells
while( $rowCount < count($result) ){ 
    $cell = $rowCount + 2;
    foreach( $cell_definition as $column => $value ){
        switch($column) {
            case 'G';
            case 'H';
            $val = '=DATEVALUE("'.date('Y.m.d',strtotime($result[$rowCount][$value])).'")';
        $objPHPExcel->getActiveSheet()->setCellValue($column.$cell, $val);
        break;
        case 'L';
        $val = date('Y.m.d H:i:s',strtotime($result[$rowCount][$value]));
        $objPHPExcel->getActiveSheet()->getStyle($column.$cell)
            ->getNumberFormat()
            ->setFormatCode("yyyy.mm.dd h:mm");
        $objPHPExcel->getActiveSheet()->setCellValue($column.$cell, $val);
        break;
        default;
        $val = $result[$rowCount][$value];
        $objPHPExcel->getActiveSheet()->setCellValue($column.$cell, $val);
        }
        }
    $rowCount++; 
} 
header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
header('Content-Disposition: attachment;filename="iPortal_Atskaite_'.date('Y-m-d_H.i.s', strtotime('+3 hour')).'.xlsx"');
header('Cache-Control: max-age=0');
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007');
$objWriter->save('php://output');
exit;

I’m using switch for columns, where I need a different cell format.

Column G and H I need format 2015.10.05 (yyyy.mm.dd) And for column L 2015.10.05 12:03 (yyyy.mm.dd H:i).

Function getStyle() doesn’t work, and returns the same value. If output as =datevalue, which is excel function, all is ok, but it doesn’t work with time.

Also, if I press edit cell in excel and press enter, that date converts to normal date for excel and all works fine.

So, the problem is with output formatting. How can I define it? For other columns, for example for numbers, all is ok.