What is a lithium-ion rechargeable battery?

What is a lithium-ion rechargeable battery? Are they better than other battery types? What impact does this technology have on hearing aid development? And what does it mean for you as a hearing aid user?

We explore the impact lithium-ion rechargeable battery technology is having on hearing aid development and what the advantages and disadvantages are for you. As with Smartphones, battery size, life and resilience have proven to be enormous challenges for hearing aid manufacturers and a bugbear for users.

Poor battery life, the difficulty and cost of replacing them, as well as the environmental impact has made the quest for a better battery a real priority. The lithium-ion rechargeable battery is a recent and exciting development in that quest for the perfect battery.

What was wrong with the old batteries?

For obvious health and environmental reasons most of the earlier batteries containing mercury were banned in the 1990s. Zinc batteries were an obvious replacement and many hearing aids still use disposable zinc-air button batteries.

These have the advantage of being very cheap to replace but they have a very short battery life—3 to 10 days. Battery life can also vary widely due to temperature, humidity, and degree of hearing loss etc. This means your batteries may run out when you least expect it.

It can also be a fiddle to have to replace them especially if you are no longer so dexterous. Plus, there is the environmental question mark over battery disposal.

Nickel-metal hydride (NiMH) batteries heralded the arrival of rechargeable batteries. These early rechargeable batteries were not very popular due to their low power capacity. They simply don’t hold a charge for long enough and often don’t meet the power needs of modern hearing aid technology. They also lose their ability to hold a charge over time and usually need replacement every 12 months or so.

The modern lithium-ion rechargeable battery meets these power challenges head on so just how good are they?

Advantages of lithium-ion batteries

The lithium-ion rechargeable battery first arrived in the 1970’s thanks to the work of chemist, Michael Stanley Whittingham. A number of major hearing aid manufacturers including Phonak, Starkey, and Signia now offer hearing aids with rechargeable lithium-ion batteries.

Modern lithium-ion rechargeable batteries offer 24 hours or more of battery life without a recharge. And that’s with continuous use including up to 5 hours of power-sapping audio streaming. This level of power reliability gives you the confidence that your hearing aids will always be on when you need them.

Recharging is easy; simply slot your hearing aids into the charging pod overnight and you’re good to go the next morning. Hearing aids such as the Phonak Audéo™ B-R or Bolero™ B-PR promise up to 36 hours of battery life on a full charge but you can still enjoy a full day of use with a truly rapid recharge time of as little as 90 minutes.

Gone too are the days of having to fiddle with changing batteries every couple of weeks. Lithium-ion rechargeable batteries sit in a sealed unit and should last up to 6 years before needing replacement. You can use this handy calculator to calculate how much money you could save every year with Signia’s Pure Charge & Go NX rechargeable batteries.

Disadvantages of lithium-ion batteries

Lithium-ion rechargeable batteries do have a few disadvantages but for most people the significant advantages will easily outweigh these minor issues.

Lithium-ion batteries sit inside sealed containers and they do have a limited lifespan (up to 6 years for the Phonak battery). This means you cannot simply swap out the old battery and replace it yourself. You will need to send the entire hearing aid to your audiologist or hearing aid specialist to have the batteries replaced.

However, this cost is generally much lower than the cost of replacing zinc batteries over that same period. It does mean you will be without your hearing aids for a short period but this is probably not a huge issue when it only happens once every 6 years or so.

Lithium-ion batteries sit in a sealed container because they contain dangerous substances that can cause a fire or an explosion if the battery is damaged. You might remember the Samsung Galaxy 7 recall after a number of the phones caught fire. There have been a few other similar cases too such as the Dell battery pack recall in 2006.

Faulty battery manufacture was identified as the cause in nearly all of these cases. Damage to the battery pack may also cause the battery to short-circuit and catch fire. Technical innovations and tightening of the regulations around battery manufacture mean that modern generations of lithium-ion batteries are now deemed safe enough to use in billions of items around the world today.

The need for a sturdy sealed battery container may add a little to the size of some rechargeable hearing aids but a Phonak sponsored study shows that 84% of hearing aid users prefer rechargeable batteries over traditional disposable batteries.

Are they right for me?

You may be thinking about having a hearing test and getting your first set of hearing aids or it may be time to replace your old ones. You probably know that hearing aids can significantly improve your life. But with such a wide range of hearing aids available it isn’t always easy to choose the right one for your needs.

Lithium-ion batteries are helping to transform the way modern hearing aids work. And the convenience and performance of modern lithium-ion rechargeable batteries are just some of the powerful reasons why you should consider them.  

Most people also love the reduced environmental impact and the cost benefits of rechargeable batteries but you may still have some questions about them. Your House of Hearing audiologist can help you weigh up whether hearing aids with lithium-ion rechargeable batteries are right for you.