A battery is a device that directly converts chemical energy into electrical energy.   It is a rechargeable battery designed to be recharged through a reversible chemical reaction.   It usually refers to a lead-acid battery.   It is a kind of battery and belongs to secondary batteries.  Battery.  Its working principle: when charging, it uses external electrical energy to regenerate the internal active material, and stores the electrical energy as chemical energy.

It uses a lead substrate grid filled with spongy lead (also known as a lattice) as a negative electrode, a lead substrate grid filled with lead dioxide as a positive electrode, and dilute sulfuric acid with a density of 1.26--1.33g/mlg/ml is used as the electrolyte.  When the battery is discharging, metal lead is the negative electrode, which undergoes an oxidation reaction to generate lead sulfate; lead dioxide is the positive electrode, which undergoes a reduction reaction to generate lead sulfate.   When the battery is charged with direct current, elemental lead and lead dioxide are formed at the two poles, respectively.   When the power source is removed, it returns to its pre-discharge state, forming a chemical battery.  The lead-acid battery can be repeatedly charged and discharged.  Its cell voltage is 2V.  The battery is a battery pack composed of one or more cells, referred to as battery.  The most common one is 6V, and the others include 2V, 4V, 8V, 24V battery.  For example, the battery used in the car (commonly known as the battery) is a battery pack of 6 lead-acid batteries connected in series to form a 12V battery.

For traditional dry-charged lead batteries (such as automobile dry-charged batteries, motorcycle dry-charged batteries, etc.), distilled water should be added after a period of use to keep the dilute sulfuric acid electrolyte at a density of about 1.28g/ml; for maintenance-free batteries, its No need to add distilled water until end of life.