A silver zinc cell is an electrochemical cell that uses silver oxide as the cathode and zinc as the anode to produce electricity. These cells are known for their high energy density and reliable performance, making them suitable for various applications.
Types of Silver Zinc Cells: Primary and Secondary
There are two main types of silver zinc cells:
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Primary silver zinc cells: These are single-use batteries, meaning they cannot be recharged. They are commonly used in hearing aids due to their compact size and high energy output. [Reference: Silver-zinc batteries are primary batteries commonly used in hearing aids, consisting of silver and zinc cells with an open-circuit voltage of 1.6 V.] An electrolyte and graphite are included to improve conductivity, and a separator prevents silver ion migration during discharge.
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Secondary silver zinc cells (rechargeable): These batteries can be recharged multiple times. They're favored in applications requiring high power output for short durations, such as torpedoes and spacecraft. [References: EaglePicher is one of the leading rechargeable silver zinc battery manufacturers; Silver–zinc batteries are the preferred choice for several non-US Navy torpedoes; Saft offers a range of both primary and rechargeable Silver-zinc battery systems for combat and exercise torpedoes; NASA research has led to advancements in rechargeable silver-zinc battery technology.]
Key Characteristics of Silver Zinc Cells
- High energy density: Silver zinc cells pack a lot of power into a small space.
- Reliable performance: They provide consistent power output.
- Relatively high voltage: They typically have a nominal voltage of around 1.5 to 1.85 volts.
- Safety: Generally considered safe, although precautions should be taken as with any battery. [Reference: Silver zinc batteries are one of the most reliable and safe technologies.]
- Limited cycle life (secondary cells): Rechargeable silver zinc batteries have a limited number of charge-discharge cycles compared to some other rechargeable technologies. [Reference: Zinc batteries may be better in cost and safety, while lithium-ion batteries excel in energy density and cycle life.]
Applications of Silver Zinc Cells
Silver zinc cells find applications in a wide variety of devices and systems, including:
- Hearing aids: Primary cells are commonly used due to their small size and high energy density.
- Torpedoes: Both primary and secondary cells are used for propulsion and other systems.
- Spacecraft: Rechargeable cells are employed where high power and reliability are crucial.
- Medical devices: Used in certain implantable and portable medical devices.
- Military applications: Utilized in various defense systems due to their performance and reliability.
- Deep-sea applications: Their robust nature makes them suitable for underwater environments. [Reference: BST Systems design and develop high energy cells, batteries and support electronics for uses from deep sea applications to planetary expeditions.]
Note: While silver-oxide batteries also use silver oxide as the cathode and zinc as the anode, they are primary cells only and differ in their construction and performance characteristics from silver-zinc batteries, which can be either primary or secondary. [Reference: For primary cell based on silver(I) oxide and zinc, see Silver-oxide battery.]
