Can a Leaky Battery Ruin Electronics?

Batteries work through chemical reactions involving corrosive chemicals such as potassium hydroxide and sulphuric acid. The chemicals react with the battery's metal case, slowly breaking it down and forming small holes through which the caustic materials leak. Once outside the battery's protective case, the chemicals can drip into surrounding electronics. Poor battery quality, age, heat, deep discharge and attempts to recharge non-rechargeable cells can cause them to leak. If chemicals remain in contact with sensitive metal components for several days, this can ruin the electronic device.

Common alkaline batteries contain a potassium hydroxide paste inside a zinc case. When you connect the battery to a circuit, ions formed between the paste and the zinc produce an electric current. Over time, the zinc deteriorates and the potassium hydroxide leaks out. If it comes into contact with metal battery terminals, the terminals corrode, cutting off the flow of electricity from the device. In some cases, you can clean this corrosion, but long-term contact ruins the terminals. Potassium hydroxide can also harm copper wiring, electronic component leads and circuit boards. The extent of the damage depends on the amount of caustic material, and how long it has spent on metal parts.

Equipment such as emergency lighting and uninterruptible power supplies, or UPS, run on sealed lead-acid batteries. These contain sulfuric acid, a potent corrosive chemical; because of the hazard potential, manufacturers design them to not leak under normal conditions. However, accidental damage can pierce the outer casing, and reverse charging can cause it to burst. If you see leakage around a sealed lead-acid battery, wear rubber gloves and eye protection before you attempt to clean it up. Neutralize the acid with liberal amounts of baking soda and dispose of the materials in a sealed plastic container.

Though alkaline batteries have largely replaced carbon-zinc formulations in consumer electronics, manufacturers still make them for low-power devices. A carbon zinc battery has a similar chemistry and construction as alkaline types, though it uses a paste of ammonium chloride and zinc chloride. As with alkaline batteries, the paste wears down the battery's zinc jacket, allowing the caustic chemical to leak out, ruining metal components if it comes into contact for enough time.

Mobile devices, such as laptop computers and cell phones, use rechargeable lithium-ion batteries. Unlike alkaline and carbon-zinc batteries, which consume their own chemicals and eventually run out of power, a lithium-ion battery has a reversible chemistry you can recharge. Though the chemicals inside may leak out, this is less likely than for non-rechargeable batteries. If they leak, the chemicals inside the battery are less likely to react with metal electronic components.