An Anti-matter Battery is a high technology energy storage device. As found, it is a small box finished in grey metal, with two gold colored contacts on its upper surface. The two contacts will provide almost unlimited current. The Battery operates by a controlled flow of anti-matter against an ordinary matter core. Flow is metered in response to demand, and very high levels of current are available. 
Anti-matter batteries are quite resistant to damage but are not armored or impervious. This type of battery is constructed to bleed energy slowly if broken or cracked. As a result, the battery will flash brightly for up to twenty minutes with very bright light and intense heat.
Batteries measure 6cm by 4cm by 10cm, and weigh about two kilograms.
Antimatter power plants come of age in the TL:16-18 technological epoch. Early prototype weapons become available in this time, but they have significant shortcomings. By TL:19-21, Antimatter becomes mainstream, affordable, and adequately miniaturized to widely used in smallarms, consumer vehicles, and even consumer goods.