It's a secondary battery capable of charging and discharging that can save twice as much energy as an ordinary CADNICA battery. Twicell uses hydrogen absorbing alloys in its negative electrode (anode) and nickel oxide in its positive electrode (cathode).

Since its release, the 1st in the world in October 1990, the "Twicell" sealed Nickel-Metal Hydride Battery has developed a strong reputation for high capacity, high performance and high quality. In November 1996, Sanyo was the 1st manufactures in the world to achieve 300 million cells accumulatively.