Prolem with encoding URL parametes which include %

I face a problem with encoding URL query, in my application it's search URL. For example, here is a peace of code:

url_path = 'http://ift.tt/1ALMoLX' + search_phrase;

Yes, I can use method encodeURIComponent() and it works:

url_path = 'http://ift.tt/1ALMoLX' + encodeURIComponent(search_phrase);

But when user search for a phrase which include symbols like '%' - it generates broken request. And in results I have 500 response with error:

URIError: malformed URI sequence

How can I encode URI parameters to prevent current problem? If I am wrong in something or don't understand correctly how it works, please explain me it. Kindly thanks for help.