Current flows through electrical devices, just as water flows through a plumbing circuit of pipes. If a water pump produces water pressure, water flows through both the pump and the circuit. Likewise with electric current in an electric circuit. For example, in a simple circuit consisting of a battery and a lamp, the electric current that flows in the lamp is the same electric current that flows through the wires that connect the lamp and the same electric current that flows through the battery. Current flows through these devices.
Energy is obtained from electricity by transformation to other forms.
It is common to say that energy is used up when it is transformed to less concentrated forms-when it is degraded. Electrical energy ultimately becomes heat energy. In this sense it is used up. No, your car battery, like all batteries, provided direct current. The ac output of the alternator is converted to dc before it charges the battery.