PHP，Excel导出换行

// 有id，才算真的有发票数据
if ($v['b_invoice_id']) {
    $v['b_invoice_info'] = json_decode($v['b_invoice_json'],true);
    $v['b_invoice_str'] .= '类型:';
    if ((int)$v['b_invoice_purchase'] === 1) { $v['b_invoice_str'] .='(收购)'; }
    if ((int)$v['b_invoice_info']['type'] === 1) { $v['b_invoice_str'] .='普通发票'; } else { $v['b_invoice_str'] .= '专用发票'; }
    $v['b_invoice_str'] .= "
公司名称/姓名:";
    $v['b_invoice_str'] .= $v['b_invoice_info']['company_name'];
    $v['b_invoice_str'] .= "
识别号/身份证:";
    $v['b_invoice_str'] .= $v['b_invoice_info']['company_tax'];
    $v['b_invoice_str'] .= "
电话:";
    $v['b_invoice_str'] .= $v['b_invoice_info']['company_telephone']?:'无';
    $v['b_invoice_str'] .= "
地址:";
    $v['b_invoice_str'] .= $v['b_invoice_info']['company_address']?:'无';
    $v['b_invoice_str'] .= "
开户行:";
    $v['b_invoice_str'] .= $v['b_invoice_info']['company_bank']?:'无';
    $v['b_invoice_str'] .= "
开户账号:";
    $v['b_invoice_str'] .= $v['b_invoice_info']['company_account']?:'无';
} else {
    $v['b_invoice_info'] = [];
}
if ($v['c_invoice_id']) {
    $v['c_invoice_info'] = json_decode($v['c_invoice_json'],true);
    $v['c_invoice_str'] .= '类型:';
    if ((int)$v['c_invoice_info']['type'] === 1) { $v['c_invoice_str'] .='普通发票'; } else { $v['c_invoice_str'] .= '专用发票'; }
    $v['c_invoice_str'] .= "
公司名称:";
    $v['c_invoice_str'] .= $v['c_invoice_info']['company_name'];
    $v['c_invoice_str'] .= "
识别号:";
    $v['c_invoice_str'] .= $v['c_invoice_info']['company_tax'];
    $v['c_invoice_str'] .= "
电话:";
    $v['c_invoice_str'] .= $v['c_invoice_info']['company_telephone']?:'无';
    $v['c_invoice_str'] .= "
地址:";
    $v['c_invoice_str'] .= $v['c_invoice_info']['company_address']?:'无';
    $v['c_invoice_str'] .= "
开户行:";
    $v['c_invoice_str'] .= $v['c_invoice_info']['company_bank']?:'无';
    $v['c_invoice_str'] .= "
开户账号:";
    $v['c_invoice_str'] .= $v['c_invoice_info']['company_account']?:'无';
}

必须是双引号。