How does a maintenance-free battery work

The car battery: how does it work and what variants are there?

How does the car battery work?

The lead-acid battery is still the most common variant. It stores electrical energy in chemical form and then passes it on as direct current. 12 volt starter batteries have six cells connected in series. Each cell consists of a stack of alternately arranged positively and negatively charged electrodes, each made up of a lead grid. These lead compound positive and negative electrodes are immersed in an electrolyte made from dilute sulfuric acid. An electrolyte is a substance in which charged particles can move. The positive electrode is made of lead dioxide and the negative electrode is made of porous lead. Special partitions, the so-called separators, separate the electrodes from one another.

The battery discharges when the current is drawn. Both electrodes are converted to lead sulphate. The battery is recharged by the generator / alternator while driving. The lead sulphate is converted back into the starting materials lead dioxide and porous lead. Because car batteries are constantly being recharged, they are also known as accumulators.

Modern cars pose major challenges for the car battery: More and more electrical consumers want to be supplied with electricity. Diesel engines and large-displacement gasoline engines also require a high cold start performance with high starting currents. And start-stop systems in particular require modern technologies that only modern starter batteries can achieve.

Basically, every starting process for the battery is associated with a high expenditure of energy. The energy consumption is particularly high in modern vehicles with an automatic start-stop system, in which the engine frequently cuts out and is restarted. Constant unloading and charging also increases the general load.