There is no remedy for patent expiration. However, if the term of the patent right expires due to force majeure, the patentee may collect relevant evidence within 2 months from the date when the obstacle is removed, or at the latest within 2 years from the date when the term expires, and request the the State Council Patent Administration Department to restore the right.
Legal objectivity:
In Article 42 of the Patent Law of People's Republic of China (PRC), the term of the invention patent right is 20 years, and the term of the utility model patent right and the design patent right is 10 years, all of which are counted from the date of application. Legal basis: Article 42 of the Patent Law has a term of 20 years for invention patents and 10 years for utility model patents and design patents, counting from the date of filing.