Facebook access_token自动续订

I have Facebook login database in my system. I am storing Long-Lived user access token with UserID to my database and I need to renew the token before it expires. I have found a page in Facebook API documentation and I tried to renew the token by following the steps. Facebook returns different access token, but expiration time is still the same.

This is what I've got: (I am using Facebook's PHPSDK 5.0.0)

$t = $this->access_token;
if ($t && $t->getExpiresAt()->getTimestamp() <= strtotime('+14 days'))
{
    $oauth = $this->fb->getOAuth2Client();
    $code = $oauth->getCodeFromLongLivedAccessToken($t, $this->redrect_urls['renew']);
    $t = $oauth->getAccessTokenFromCode($code, $this->redrect_urls['renew']);
    if ($t)
    {
        $this->database->table($this->config->getTable('facebook-logins'))
            ->where('user_id', $this->user_id)
            ->update(array(
                'expires_at'    => $t->getExpiresAt(),
                'access_token'  => $t->getValue(),
                'facebook_name' => $this->getUserAccount()['name'],
            ));
    }
}

What should I do to renew the token expiration date? Is it possible to do this token renewal fully automatically without bothering the user to click on link or whatever?

Thanks for any tips, TheKronnY