Battery acid is a common term for the liquid found within certain types of batteries, primarily those used in vehicles and backup power systems. This substance is fundamental to how these batteries operate, enabling the chemical reactions that generate electricity. Understanding its properties clarifies its function and highlights the need for careful handling and proper disposal.
Common Identity
What is commonly called battery acid is chemically known as sulfuric acid. Its chemical formula is H₂SO₄. This acid is a diluted solution of sulfuric acid and purified water within the battery casing. In lead-acid batteries, the concentration of sulfuric acid in water commonly ranges from 29% to 32% by weight. Battery acid is highly corrosive and has a very low pH, around 0.8, due to its high concentration of hydrogen ions.
Role in Energy Storage
Sulfuric acid plays a central role in lead-acid batteries, functioning as the electrolyte. It facilitates the movement of ions between the battery’s lead plates, made of lead and lead dioxide. This ionic movement enables the electrochemical reactions that allow the battery to store and release electrical energy.
When the battery discharges, the sulfuric acid reacts with the lead and lead dioxide plates, forming lead sulfate and water. This process consumes the sulfuric acid, making the electrolyte less concentrated. During charging, the chemical reaction reverses, converting the lead sulfate back into lead, lead dioxide, and regenerating the sulfuric acid.
Safe Handling and Disposal
Battery acid is a highly corrosive substance that can cause severe chemical burns to skin and eyes upon contact. It can also damage clothing and other materials. Therefore, wearing appropriate personal protective equipment (PPE), such as acid-resistant gloves, safety goggles, and protective clothing, is important when handling batteries or battery acid. If skin contact occurs, immediately flush the affected area with large amounts of cool, running water for at least 15 minutes. For eye contact, flush with water for 15 to 30 minutes and seek immediate medical attention. In case of ingestion, call emergency services immediately and rinse the mouth with cold water, sipping water until help arrives.
Proper disposal of lead-acid batteries is important to prevent environmental contamination, as they contain lead and sulfuric acid. It is illegal in most places to dispose of used lead-acid batteries in regular trash or landfills. These batteries should be taken to authorized recycling centers, auto parts retailers, or service shops that accept them. Recycling processes can recover up to 99% of the materials, including the lead and plastic, and the sulfuric acid can be neutralized or converted for other uses. This closed-loop recycling helps protect the environment from toxic materials.