Lead Acid-NiMH Hybrid Battery System Using Gel Electrolyte

Abstract

A hybrid battery system with gel electrolytes is proposed here to alleviate some limitations on conventional batteries, such as maintenance cost and acid stratification for the lead-acid battery, high self-discharge and short life cycles for high current discharge for nickel-metal hydride battery. This hybrid battery consists of a lead-acid positive electrode and a nickel-metal hydride negative electrode, operating in H2SO4-silica gel and KOH-potassium salt poly(acrylic acid) gel electrolytes via monopolar ion exchange membranes, respectively. The hybrid battery using gel electrolyte maintained stable discharge plateau at 2.27 V and longer discharge capacity than wet electrolyte system. This improved performance may be due to the gel electrolyte which can prevent acid stratification, reduce the corrosion rate of electrodes, and resolve the problem of salting-out in the central chamber for aqueous electrolyte system.