Acid burns to the face and eyes comprise about 50% of injuries related to the use of lead acid batteries. The remaining injuries were mostly due to lifting or dropping batteries as they are quite heavy. Lead acid batteries are usually filled with an electrolyte solution containing sulphuric acid.
The lead acid battery works well at cold temperatures and is superior to lithium-ion when operating in sub-zero conditions. Lead acid batteries can be divided into two main classes: vented lead acid batteries (spillable) and valve regulated lead acid (VRLA) batteries (sealed or non-spillable). 2. Vented Lead Acid Batteries
Sulphuric acid electrolyte spilled from lead acid batteries is corrosive to skin, affects plant survival and leaches metals from other landfilled garbage. Therefore, lead acid batteries are considered as hazardous waste and shall not be placed into regular garbage.
2. Vented Lead Acid Batteries Vented lead acid batteries are commonly called “flooded”, “spillable” or “wet cell” batteries because of their conspicuous use of liquid electrolyte (Figure 2). These batteries have a negative and a positive terminal on their top or sides along with vent caps on their top.
Vented lead acid batteries vent little or no gas during discharge. However, when they are being charged, they can produce explosive mixtures of hydrogen (H2) and oxygen (O2) gases, which often contain a mist of sulphuric acid. Hydrogen gas is colorless, odorless, lighter than air and highly flammable.
During normal operation, water is lost from a non-sealed (or flooded) lead-acid battery due to evaporation. If the electrolyte levels are below the plates, hydrogen/oxygen can accumulate and potentially cause an explosion. Many lead-acid battery explosions are believed to occur under these conditions.