K-Patents Application of the Month: Sulfuric Acid in the Lead-Acid Battery Manufacture

Battery manufacture is the process of producing lead-acid and gel batteries commonly used for automobiles and electric vehicles that need long service periods and durability.

Sulfuric acid (H2SO4) activates the lead elements of the lead battery resulting in the power effect. The correct effect can be obtained only with the right acid concentration. If the sulfuric acid concentration is too high, it causes corrosion of the lead. Evaporation of the acid may occur due to the exothermic reaction, which means that the concentration is likely to change during processing.

Fresh acid is mixed with water in a buffer tank and the solution is then pumped into a lead activation plant. After the activation plant the acid is recovered back to the buffer tank.

K-Patents Teflon Body Refractometer PR-23-M measures in-line the sulfuric acid concentration in the acid inlet and recovery lines. A typical mounting point is in a by-pass loop across the pump inlet and outlet.

Typical measurement range of sulfuric acid is 1030 - 1500 g/l (equivalent to 5-60 % by weight). By measuring the sulfuric acid the correct power activation effect is reached and the potential acid concentration fluctuations are instantly revealed.

Application Note: 4.06.07 Lead Acid Battery manufacture (pdf)