Leakage of Alkaline Batteries

Alkaline Battery

An alkaline battery (IEC code: L) is a type of primary battery that provides direct electric current from the electrochemical reaction between zinc and manganese dioxide (MnO₂) in the presence of an alkaline electrolyte.

The alkaline battery gets its name because it has an alkaline electrolyte of potassium hydroxide (KOH) instead of the acidic ammonium chloride (NH₄Cl) or zinc chloride (ZnCl₂) electrolyte of the zinc–carbon batteries. Other battery systems also use alkaline electrolytes, but they use different active materials for the electrodes.

The primary alkaline battery is a widely used product, which is essential for powering many portable devices, such as power tools, radios, toys, and remote controls. The most common size of alkaline battery is the well-known AA battery. Alkaline batteries are most commonly used in portable devices that have low current drains, are used only intermittently, or are used well away from an alternative power source, such as in alarm and communication circuits where other electric power is only intermittently available.

Why do batteries leak?

Alkaline batteries are prone to leaking potassium hydroxide (KOH), a caustic agent that can cause respiratory, eye and skin irritation. The reason for leaks is that as batteries discharge — either through usage or gradual self-discharge — the chemistry of the cells changes and some hydrogen gas is generated. The outer casing of the battery prevents the hydrogen gas from leaking. However, if a battery is left unused in a device for an extended period, the resulting gas buildup can rupture the casing and cause leakage. 

What leaks out of batteries?

It is the electrolyte that can start to leak and form white crystals on the outside of the battery. Potassium hydroxide is the most common chemical to leak out of batteries. Aqueous potassium hydroxide is employed as the electrolyte in alkaline batteries based on nickel-cadmium, nickel-hydrogen, and manganese dioxide-zinc. It’s a highly corrosive base that can cause skin irritation and respiratory issues if inhaled.

Is a leaking battery harmful?

A leaking battery is a serious problem that can make your phone or other electronic devices unusable. In addition, since the chemical that leaks out of a battery is typically an acid, it can harm the environment and human eyes and skin. If you touch a leaking battery, it can cause skin burns. Rinse immediately with running water. 

How can you prevent batteries from leaking?

The risk of leaks out of batteries can be reduced by the following precautions:

• Do not attempt to recharge disposable alkaline cells
• Do not mix different battery types in the same device
• Try to replace all of the batteries in the device at the same time
• Storing batteries in a dry place and at room temperature
• Remove batteries for storage of devices