Often hearing aid users wonder if their hearing aids are safe to use and if they contain the heavy metal lithium. So, I combined my knowledge as an audiologist and did some extra research to find out how many hearing aids contain lithium.
So, do hearing aid batteries contain lithium? Recently introduced rechargeable hearing aids are made out of lithium-ion batteries that do contain lithium. These should not be confused with traditional disposable zinc-air batteries that do not contain lithium. Lithium batteries are considered safe to use in a hearing aid but could be fatal if swallowed.
Many hearing aid users selected the type of battery their hearing aid uses based on a convenience factor. Do they want disposable or throw-away batteries or would they rather put the hearing aid into a charger each night? While this convenience question is important, one should also consider the safety factor of having heavy metals in the batteries.
80% of Hearing Aids Now use Lithium Batteries
Over 2 million hearing aids are sold annually in the United States. Up until 2017, 99% of them used disposable zinc-air batteries that did not contain any lithium.
However, changes in the market have introduced lithium hearing aid batteries. Many of the major manufacturers offer lithium-ion batteries in their hearing aids. These manufacturers are Phonak, Oticon, Unitron, Starkey, GN Resounds, Widex, and Sivantos.
When Phonak released their first lithium-ion-powered hearing aid in late 2017. It was immediately successful and overnight jumped to around 30% of their receiver-in-the-ear hearing aid sales. Over time, sales dropped to around 20% of the market share. Other hearing aid manufacturers saw the same thing after their initial launch.
It wasn’t problems with the batteries that cause sales to drop but other design flaws (ie. difficulty to turn hearing aids on/off) that caused sales to drop. Now in 2019, manufacturers are in their second release of lithium-ion devices and sales have risen to over 80% of the market share and are still rising.
Are Lithium-ion Batteries Safe?
Lithium-ion batteries are overall very safe to use in hearing aids. However, they are not safe to eat or have your pet mistakenly eat (If you are worried about a pet swallowing a hearing aid or battery see my complete article here).
As lithium is toxic, the battery is required to be fully encased inside the hearing aid. With the battery installed in the hearing aid, it makes it much more difficult to be eaten.
With a battery the size of a button, they often get lost on the floor and mistakenly eaten by a pet or child. There have also been cases where an elderly adult mistakenly swallows a battery thinking they are taking a medication pill. To reduce the chance of this happening the manufacturers are required to only allow professionals to change the batteries in the hearing aids.
Previously Bad Press about Lithium-ion Batteries
Last year there was a lot of bad press about lithium-ion batteries, certain cell phones were catching on fire while they were charging. This has not occurred with hearing aids.
Also, I should point out that it would be impossible to charge a hearing aid battery while it is in use so there could not be an incident of the hearing aid catching fire while someone was wearing it on top of their ear.
I have kept my ear to all news regarding rechargeable hearing aid batteries for the past few years and there are plenty of complaints with the z-powered silver-zinc batteries having many problems (not fire problems but intermittency problems) but there have been almost no complaints with the lithium-ion batteries.
Given the fact that half a million of these devices have been sold and there have been no known issues, I believe that they are safe to purchase.
I would forecast that in the coming years, more and more hearing aids will be converted to lithium-ion batteries as they are overall safe to use in a hearing aid.
Disadvantages of Lithium Hearing Aid Batteries
As was mentioned before, the lithium hearing aid battery must be fully encased in the hearing aid so that it is less likely to be swallowed by a child, elderly adult, or pet.
Some people consider this a disadvantage of the battery because if the battery goes bad you will need to have an audiologist send it back to the hearing aid manufacturer for replacement in order to get a new one. Which is rather inconvenient. Learn how to troubleshoot the charger.
When considering this, think about your cell phone’s battery life. When the phone is brand new you may get 2 full days out of the battery before recharging it. However, when the phone is getting to around 2 years old the battery life seems to shorten and the battery is likely to die much quicker.
For this reason, hearing aid manufacturers have made the batteries last much longer than a typical day. The average time a person spends wearing a hearing aid is usually 10-12 hours. Generally speaking, the typical Audiologist would consider full-time use of the hearing aids anything around the mark of 8 hours.
Phonak’s rechargeable hearing aid advertises 24 hours of use before going dead, however, depending on your hearing loss it may last up to 30 hours of use. Thus, it will give you many years of use before not lasting a full day of wear time and need to be sent in for replacement.
On average, a hearing aid will be sent back to the manufacturer for some repair issue. Each time an aid is sent in for repair the battery will automatically be replaced. Thus, the lithium-ion battery is probably going to last longer than you keep the hearing aids. Most people upgrade hearing aids every 3-5 years.
Do hearing aid batteries contain mercury? Rechargeable hearing aid batteries do not contain mercury. Disposable batteries once did contain trace amounts of heavy metal mercury, however, almost all batteries sold today do not contain mercury. Each zinc-air battery packages that do not contain it will be labeled as ‘mercury-free’ or Hg 0%.
Is there lead in hearing aid batteries? Zinc-air hearing aid batteries contain a trace amount of lead in them. The trace amount of lead would not be considered toxic if ingested only a single time.