Yes, the weight of a battery typically increases when it is fully charged. This is due to the fact that during the charging process, chemical reactions occur within the battery, causing ions to move between the electrodes and the electrolyte. As a result, the overall mass of the battery increases.
In lead-acid batteries, for example, when the battery is charged, lead sulfate (PbSO4) on the electrodes converts back into lead (Pb) and lead dioxide (PbO2), and sulfuric acid in the electrolyte replenishes. This conversion leads to an increase in the mass of the electrodes and the electrolyte, thereby increasing the weight of the battery.
The weight increase might not be significant for small batteries, but it can be noticeable for larger batteries, especially in applications such as electric vehicles or backup power systems where batteries have substantial capacities.
It’s worth noting that the weight increase is reversible; when the battery discharges, the chemical reactions occur in the opposite direction, and the battery loses weight as it releases energy.
