While there are rechargeable batteries available on the market, the most common type is still the zinc-air button disposable battery. Traditionally hearing aid batteries were produced using trace amounts of mercury to assist with conductivity and stabilize internal components, but mercury is no longer used in hearing aid batteries. Because zinc-air batteries are air-activated, a factory-sealed sticker allows them to remain inactive until it is removed. Once peeled from the back of the battery, oxygen will interact with the zinc in the battery and “turn it on.” To get the best performance from a zinc-air battery, wait about one minute after removing the sticker to fully activate before placing it in the hearing device.
Zinc-air batteries remain stable for up to four years when stored in a room temperature, dry environment. Hearing aids come in many different sizes and styles and with different power needs. Larger hearing aids require larger batteries. Additionally, hearing aids for people with severe or profound hearing losses typically require more power and larger batteries. There are five sizes of hearing aid batteries available on the market. The sizes from smallest to largest are: 5, 10, 312, 13 and 675. The most common battery size for cochlear implants is 675.