faveo/vendor/maatwebsite/excel/docs/export/sizing.md

Cell size

Set column width

To set the column width use ->setWidth($cell, $width).

// Set width for a single column
$sheet->setWidth('A', 5);

// Set width for multiple cells
$sheet->setWidth(array(
    'A'     =>  5,
    'B'     =>  10
));

Set row height

To set the row height use ->setHeight($row, $height).

// Set height for a single row
$sheet->setHeight(1, 50);

// Set height for multiple rows
$sheet->setHeight(array(
    1     =>  50,
    2     =>  25
));

Set cell size

To set the cell size use ->setSize($cell, $width, $height).

// Set size for a single cell
$sheet->setSize('A1', 500, 50);

$sheet->setSize(array(
    'A1' => array(
        'width'     => 50
        'height'    => 500,
    )
));