We use batteries constantly. You are probably using one right now. As technology has exponentially increased over the last few decades, we have seen battery technology result in more and more power packed into smaller and smaller compartments. But how much do you know about the batteries you are using right now? Probably not a whole lot. Maybe you remember the phrase “lithium ion” being thrown around in a television commercial, but that’s probably it. When it comes to your laptop, wall clock, or cellphone, being ignorant of the batteries you’re using may result in a few inconveniences, but it’s hardly a life or death situation. But what about when it is? What about the batteries used in medical devices? That is the definition of a life or death scenario, so we are going to do our best to give you the inside scoop. Here are the three most common batteries used in medical aid devices.
1) Zinc-Air Battery
Zince-Air batteries are electro-chemical batteries powered by oxidizing zinc with oxygen from the air. These are relatively cheap to produce and contain extremely high energy densities. The sizes made range from tiny button cells for hearing aids, larger batteries used in film cameras that previously employed mercury batteries, to rather large batteries used for electric vehicle propulsion. Basically, these are your vintage camera and hearing aid batteries. The became a primary, replacement for mercury zinc-oxide batteries after such batteries were effectively banned by Congressional legislation in 1996. While zinc-air batteries do not last nearly as long as their mercury counterparts, they can be made to fit into the same equipment that had previously used the mercury batteries, cementing their status as the primary replacement. Zinc-air batteries have a long shelf life, as much as three years, if sealed in airtight packaging. Once opened, however, the air is a natural part of the oxidizing process, and the batteries discharge rather quickly. If you purchase Redding hearing aid batteries, these are probably what you’re getting.
2) Lithium-Iodide Battery
Lithium-Iodide batteries are disposable batteries that use lithium as an anode. They are the new industry standard for medical devices and are characterized by long charge life and high cost per unit. Also referred to simply as Lithium batteries, these batteries are the number one choice for long-life devices such as pacemakers and virtually any other modern medical device. Lithium batteries can be specialized to last reliably for more than 15 years but are also quite expensive.
Nickel-Cadmium batteries, also known as NiCad batteries, are a century-old technology also on it’s way out. They were invented in 1898, and were once popularly used in portable power tools, photography equipment, flashlights, emergency lighting, and portable electronic devices. However, the superior capacity and lower cost of Nickel-metal hydride batteries has served to make them obsolete in some areas. Additionally, the environmental impact of the disposing the battery’s heavy metal cadmium has resulted in legislation reducing its use. Within the European Union, they can now only be supplied for certain types of new equipment, such as medical devices, or as replacement batteries for critical equipment that cannot use any other type.