Unfortunately the answer is yes. Battery on a peace officer under California law, Penal Code 243(b) or 243(c) PC, is a crime even if the officer isn't injured.
The same thing is true of simple battery under California Penal Code 242 PC. A "battery" is any harmful or offensive touching of another person--it doesn't have to cause an injury of any kind.
But there is some good news. Under PC 243(b), battery on a peace or police officer that does not cause injury carries only California misdemeanor penalties. The maximum sentence for battery on a peace officer without injury is up to one (1) year in county jail, and the maximum fine is two thousand dollars ($2,000).
(In contrast, battery on a peace officer that does cause injury is charged under Penal Code 243(c)(2) PC and can carry felony penalties, including a much longer jail sentence.)
Plus, there are other ways to fight PC 243(b) battery on a peace officer charges. Our criminal defense attorneys have seen many people successfully argue that they are not guilty because they did not act willfully, or because the officer was engaged in police misconduct at the time when the alleged battery occurred.