Zinc Air Batteries
Highest quality: mercury-free and “Made in Germany” – in your proprietary label packaging as well
These batteries are used almost exclusively in hearing aids, therefore they are generally referred to as “hearing aid batteries.” There are four main types, which are provided with a color code on the packaging regardless of manufacturer: 10 (yellow), 13 (orange), 312 (brown) and 675 (blue). Furthermore, there are special types in the sizes 675 and 13 for implanted hearing aids.
Zinc air batteries are the ideal power supply for analog and digital hearing aids in the shape of a button cell because of their particularly high energy density and an almost horizontal discharge curve.
Zinc-air batteries have to be disposed of properly in Germany according to the Battery Act (BattG) (and likewise in many other countries as well, because the BattG is based on a European directive). Batteries are collected at retail locations in containers provided for that purpose. Batteries should not be disposed of in any other waste collection containers or in the environment because they contain contaminants and recoverable materials.
A zinc air battery is a primary cell, i.e. non-rechargeable. In terms of structural design, zinc air batteries consist of an anode made of zinc powder, the cathode is formed from the oxygen in the air, the electrolyte is potassium hydroxide, and the catalyst is a graphite rod, graphite powder or carbon lattice (graphene). In the usual structure of a button cell there is a separator and the carbon lattice between the zinc powder and the oxygen. The supply of the oxygen takes place through small air holes, which are sealed until use by adhesive tapes. Once the air holes are opened and oxygen is supplied, the zinc oxidizes with the oxygen. The open circuit voltage is 1.35 to 1.4 V.
Thus, zinc-air batteries are in the same voltage range as the no longer manufactured mercury zinc batteries and replaced these in hearing aids. Any released energy is used electrochemically.
Since zinc-air batteries react with oxygen and produce energy, keeping them sealed off from air during storage and prior to use is very important, otherwise the battery discharges itself. If there is no air supply, the self-discharge is about 3% a year.