In circuit diagrams, the battery symbol represents a source of electrical energy that provides a voltage difference to drive the flow of electrical current through the circuit.

The battery symbol is typically depicted as a series of one or more cells connected together, with each cell consisting of a positive (+) terminal and a negative (-) terminal. The number of cells and their arrangement in the battery symbol may vary depending on the circuit design and the voltage and current requirements of the components in the circuit.

The positive terminal of the battery is usually represented by a long vertical line with a shorter horizontal line on top, while the negative terminal is represented by a shorter vertical line with a longer horizontal line on the bottom. The longer horizontal line on the positive terminal indicates that it is the higher potential terminal of the battery, while the longer horizontal line on the negative terminal indicates that it is the lower potential terminal.

The battery symbol may also include additional markings to indicate the type of battery being used, such as the chemical composition or voltage rating. For example, a battery symbol with a "9V" label indicates that the battery is a 9-volt battery.

In some circuit diagrams, the battery symbol may also include arrows to indicate the direction of current flow. For example, if the battery is connected to a light bulb, the arrows in the battery symbol would point towards the bulb to indicate that current flows from the positive terminal of the battery towards the bulb, and then back to the negative terminal.

In summary, the battery symbol in a circuit diagram represents a source of electrical energy that provides voltage difference to drive the flow of electrical current through the circuit, and its appearance may vary depending on the number of cells and their arrangement, as well as the type of battery being used.