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Section 1: Battery Overview
For over 35 years, Energizer has manufactured miniature Zinc Air batteries primarily designed to provide power to miniature hearing aids. Zinc Air chemistry provides the highest available energy density compared to other commercially available batteries. Energizer Zinc Air Prismatic batteries employ technology similar to what is used in hearing aid batteries, but with a thin prismatic form factor providing power for a broad range of applications.
1.1 ‐‐ Zinc Air Chemistry
Zinc Air batteries are based on the alkaline chemistry (Zn/MnO2) used in standard AA and AAA primary batteries. The high energy density of Zinc Air results from replacing the manganese dioxide (MnO2) cathode with a thin air electrode. This air electrode contains carbon which catalyzes oxygen to allow it to react with zinc. The thin air electrode eliminates the need to contain both reactants in the battery, so the majority of the battery can be filled by the zinc anode. As a result Zinc Air provides the highest available energy density compared to commercially available batteries.
The typical open circuit voltage (OCV) of Zinc Air is 1.4 V. Under load, the operating voltage is generally between 1.10 and 1.30 volts. The half cell and overall reactions for a Zinc Air battery are as follows:
Anode: | 2Zn + 4OH‐ → 2ZnO + 2H2O + 4e‐ |
Cathode: | O2 + 2H2O + 4e‐ → 4OH‐ |
Overall: | 2Zn + O2 → 2ZnO |
1.2 ‐‐ Construction
Air holes are designed into the battery container to allow oxygen to flow into the battery. Because exposure to the environment can degrade battery performance over time, the air holes are sealed by a tab prior to consumer use. The tab must be removed before the battery is placed into a device. Once air enters the holes, it flows through an air distribution layer. This layer helps to distribute air across the entire air electrode. Figure 1 shows a cross section of an Energizer Zinc Air prismatic battery.
ENERGIZER BATTERY MANUFACTURING
VERSION 1.2