Simple Misdemeanor Battery per California Penal Code 242 does not require injury. Any rude or angry touching of another can be a battery even without injury. The law protects individuals from any willful touching in a harmful or offensive manner, and which is not in done self defense. Simple Assault per PC 240 requires someone to have the present ability to apply force and willfully act, not in self defense, in a way that a reasonable person would believe the probable result would be a battery. Assault is more of a threatening and actual touching is not required for PC 240.
Injury is not required in a "battery" case. A misdemeanor battery is without injury, and may simply be an unlawful use of force against another ....a rude or angry touching of the individual. There are more serious charges that are felonies if there is an injury depending on the seriousness of the injury. Battery can also vary in seriousness depending on the "victim". If the "victim is a spouse or someone that you have had a romantic relationshipwith, then it is domestic violence and has greater consequences. Additionally if the "victim" is a child, police officer, emergency personnel, teacher or other special person under the law, then penalties can also be greater as well as the charges.
A criminal "battery" charge is a misdemeanor offensive touching. The charge does not require any injury whatsoever. It could be a shove, a punch, a slap, a grabbing or any rude or angry touching. It has to be unlawful and intended, not accidental and not in self defense. Words alone, like name calling, do not justify any unlawful touching. The California Penal Code (PC) section is 242. That charge carries up to 6 months jail and $1000 fine. Additionally, it is one of those charges that prohibits gun ownership or possession for 10 years. If there is a weapon involved or injury, then it could be a felony.