|Part of the common law series|
|Liability and remedies|
|Duty to visitors|
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At common law, battery is the tort of intentionally (or, in Australia, negligently) and voluntarily bringing about an unconsented harmful or offensive contact with a person or to something closely associated with them (e.g. a hat, a purse). Unlike assault, battery involves an actual contact. The contact can be by one person (the tortfeasor) of another (the victim), or the contact may be by an object brought about by the tortfeasor. For example, the intentional contact by a car is a battery.
Unlike criminal law, which recognizes degrees of various crimes involving physical contact, there is but a single tort of battery. Lightly flicking a person's ear is battery, as is severely beating someone with a tire iron. Neither is there a separate tort for a battery of a sexual nature. However, a jury hearing a battery case is free to assess higher damages for a battery in which the contact was particularly offensive or harmful.
Contact required 
Battery is a form of trespass to the person and as such no actual damage (e.g. injury) needs to be proved. Only proof of contact (with the appropriate level of intention or negligence) needs to be made. If there is an attempted battery, but no actual contact, that may constitute a tort of assault.
In the United States, the common law requires the contact for battery be "harmful or offensive". The offensiveness is measured against a reasonable person standard. Looking at a contact objectively, as a reasonable person would see it, would this contact be offensive? Thus, a hypersensitive person would fail on a battery action if jostled by fellow passengers on a subway, as this contact is expected in normal society and a reasonable person would not find it offensive. Harmful is defined by any physical damage to the body.
Battery need not require body-to-body contact. Touching an object "intimately connected" to a person (such as an object he or she is holding) can also be battery. Furthermore, a contact may constitute a battery even if there is a delay between the defendant's act and the contact to the plaintiff's injury. For example, where a person who digs a pit with the intent that another will fall into it later, or where a person who mixes something offensive in food that he knows another will eat, has committed a battery against that other when the other does in fact fall into the pit or eats the offensive matter.
Because courts have recognized a cause of action for battery in the absence of body-to-body contact, the outer limits of the tort can often be hard to define. The Pennsylvania Superior Court attempted to provide some guidance in this regard in Herr v. Booten by stressing the importance of the concept of one's personal dignity. In that case, college students purchased and provided their friend with alcohol on the eve of his twenty-first birthday. After drinking nearly an entire bottle of Jack Daniels whiskey, the underage man died of acute ethanol poisoning. Reversing the decision of the trial court, the Pennsylvania Superior Court held that supplying a minor with alcoholic beverages, while certainly constituting a negligent act, did not rise to the level of a battery. In the words of Judge Montemuro, supplying a person with alcohol "is not an act which impinges upon that individual's sense of physical dignity or inviolability."
Awareness not required 
The victim of a battery need not be aware of the act at the time for the tort to have occurred. For example, if a surgeon performing an appendectomy on an unconscious patient decides to take out the patient's spleen for his personal collection, the surgeon has committed a battery against the patient. Similarly, a battery occurs if the surgeon allows a cousin who is a plumber with no medical training to help fish out the appendix during the surgery. Although the patient has consented to being touched by the surgeon, this consent does not extend to people who the patient would not reasonably anticipate would be participating in the procedure.
The battery may occur even if the victim is unaware of the contact at the time and the defendant is nowhere near the scene at the time of the contact. If a tortfeasor puts an offensive substance in another person's food, and the other person consumes the offensive substance, the battery has been committed even if the victim is not made aware that they have eaten something offensive until much later.
Degree of intent 
The degree and quality of intent in civil (tortious) battery is different to that for criminal battery. The degree and quality of intent sufficient for battery also varies between common law countries, and often within differing jurisdictions of those countries. In Australia, negligence in an action is sufficient to establish intent. In the United States, intention to do an act that ultimately results in contact is sufficient for the tort of battery, while intention to inflict an injury on another is required for criminal battery.
Intent can be transferred with battery, i.e. a person swings to hit one person and misses and hits another. He or she is still liable for a battery. Intent to commit a different tort can transfer in the same way. If a person throws a rock towards one person intending only to scare them (but not to hit them), they will be liable for battery to a different person who is hit by that rock.
The standard defenses to trespass to the person, namely necessity, consent, self defense, and defense of others, apply to battery. As practical examples, under the first, a physician may touch a person without that person's consent in order to render medical aid to him or her in an emergency. Under the second, a person who has, either expressly or impliedly, consented to participation in a contact sport cannot claim in battery against other participants for a contact permitted by the rules of that sport, or expected to occur within the course of play. For example, a basketball player who commits a hard foul against an opposing player does not thereby commit a battery, because fouls are a regular part of the course of the game, even though they result in a penalty. However, a player who struck another player during a time-out would be liable for battery, because there is no game-related reason for such a contact to occur.
Self-defense as to battery can consist only of engaging in physical contact with another person in order to prevent the other person from themselves engaging in a physical attack.
- See, e.g. Fisher v Carrousel Motor Hotel, Inc., 424 S.W.2d 627 (1967).
- See, e.g., Leichtman v. WLW Jacor Communications, 92 Ohio App.3d 232 (1994) (cause of action for battery where tortfeasor blew cigarette smoke in another's face).
- 580 A.2d 1115 (Pa. Super. Ct. 1990).
- Id. at 1117.
- Talmage v Smith, 101 Mich. 370, 59 N.W. 656 (Mich. 1894).