A battery works as follows

WARNING: This page is about a different car, the 2002 Volvo C70, 2001 Volvo C70, 2000 Volvo C70, 1999 Volvo C70, and 1998 Volvo C70. However, it is still accessible from the selected car via links, so may be relevant.

The battery consists of several cells. Schematically, a battery can be said to be made up of two electrodes, one positive and one negative. These electrodes are different materials, which are submerged in a container filled with electrolyte, often called battery acid. As a result of the different electrode materials, there is an electrical charge between the positive and negative electrodes. There is a chemical reaction between the electrodes and the electrolyte causing electrical energy to be generated. If the positive and the negative poles of the electrodes are connected to form a closed circuit, a current flows through the circuit.

In a lead accumulator, the positive electrode consists of lead oxide and the negative electrode of porous lead. The electrolyte consists of diluted sulfuric acid (H₂ SO₄ ) which is a mixture of concentrated sulfuric acid and distilled or deionized water.