Although both types of batteries are zinc-air batteries with the same voltage, their requirements for capacity and performance differ: the maximum discharge current of a regular hearing aid 675 battery is 20mA; while the maximum discharge current of a cochlear implant-specific battery is 30mA. The maximum current value for hearing aid operation is generally 1-1.5mA, while the maximum current value for cochlear implant operation is generally 1.2-1.9mA. Some users have reported that the sound from a cochlear implant battery is louder and clearer, which is actually a normal state under the high-power operation of the cochlear implant.
The voltage and current of batteries specifically designed for cochlear implants are stable, and they can be used in high-power digital hearing aids. However, when used in general low- to medium-power hearing aids, the discharge time is not much longer, making them somewhat unnecessary from an economic standpoint.
Because cochlear implant batteries have a larger operating current, their vent size is larger than that of hearing aid batteries. The larger vent allows for a larger reaction with a large amount of oxygen to discharge, so the self-discharge is faster after the sticker is removed, and the usage time is slightly shorter than that of hearing aid batteries.
In general, the battery of a hearing aid is installed in the cochlear implant. The voltage is unstable and the discharge curve is not ideal, so the cochlea operates in a low-power state. In some multi-channel cochlear implants, there may even be intermittent speech, which may affect the child's speech accuracy. Parents often cannot detect these situations in time.
In practical use, cochlear implants use three batteries connected in series, so the requirements for battery stability are higher, requiring more consistent discharge curves. This also places higher demands on the battery casing manufacturing process and chemical formula, requiring a dedicated cochlear battery production line for customization.
Therefore, although the two have the same battery size and type, cochlear implants still require dedicated batteries to ensure the continuous and stable operation of the cochlear implant chip.
In Europe and the United States, hearing aid batteries and cochlear implant batteries are used in strict contrast.
It is recommended that middle-aged and elderly people not replace cochlear implant batteries with ordinary 675 hearing aid batteries because of a slight price difference, as this would affect the full functioning of the cochlea and result in greater losses than gains.
