Detailed structure of alkaline batteries


Alkaline batteries have the advantages of high specific […]

Alkaline batteries have the advantages of high specific energy and volumetric energy density, long storage life, and large current discharge. These advantages are inseparable from the internal structure of alkaline batteries. Alkaline batteries are mainly composed of four parts: electrode, electrolyte, diaphragm, and casing.
(1) Shell. The shell is a container of electrode material. Generally, the shell is required to have high mechanical strength, and also have good resistance to vibration, impact, corrosion, and temperature difference. The shell of mercury-free alkaline zinc-manganese battery Generally, a steel shell is used.
(2) Electrode. The main components of the cathode material of alkaline batteries are MnO2 and graphite. However, in order to improve the discharge performance of the battery, some battery manufacturers often use doped modified MnO2, which is mixed with conductive agents such as graphite and acetylene black. , And then pressed into the binder. The negative electrode material of alkaline batteries is mainly composed of zinc powder, electrolyte, gelling agent and a small amount of corrosion inhibitor.

(3) Electrolyte, the electrolyte is responsible for transferring charge between the positive and negative electrodes inside the battery, and requires high specific conductivity and stable chemical properties. A certain amount of zinc oxide must be added to the electrolyte to achieve the effect of inhibiting the reaction of zinc with alkali and reducing the self-dissolution of the zinc electrode. Recent studies have shown that the amount of zinc oxide added should not be too much, otherwise the precipitation of zinc oxide and the formation of microelectrodes with zinc will accelerate the precipitation rate of hydrogen.
(4) Separator. The basic function of the separator in alkaline zinc-manganese batteries is to mechanically isolate the positive and negative materials to avoid short circuits inside the battery. When the battery is discharged, it is required that the diaphragm does not produce greater resistance to the directional movement of conductive ions, otherwise the internal resistance of the battery will increase and the discharge performance of the battery will be affected. In addition, the diaphragm is required to have stable chemical properties, a certain mechanical strength, and prevent the growth of dendrites on the electrode.