The super battery is a kind of hybrid energy storage element, which is composed of two parts, including the lead-acid battery part and the asymmetric super capacitor part, which are connected in parallel in an internal non control circuit mode. The super battery realizes the integration of lead acid battery and super capacitor in terms of structure design and battery use function. The so-called integration is to combine the above two in the same single battery system.

The lead-acid battery is generally composed of 3 or 6 single cells in series, consisting of plates, separators, electrolyte, a shell, poles and a liquid filler plug (not available for maintenance free batteries).

Generally speaking, the batteries used in automobiles are mainly divided into two types: water-added lead-acid batteries and maintenance-free lead-acid batteries. At present, most models use maintenance-free lead-acid batteries. However, there are also many Japanese cars, including some high-end models, and some use non-maintenance-free lead-acid batteries.

As a traditional battery, lead-acid battery has become a common battery in daily life due to its low cost and rechargeable advantages. Adding water for repeated use is a common method, so when the liquid level of the lead-acid battery is too low, under what circumstances is it allowed to add water to make it work better?