Yes if you need to wear hearing aids and need to bring hearing aid batteries onto the plane in your carry on luggage or some spare hearing aid batteries in your checked luggage you are allowed to bring enough spare hearing aid batteries onto the plane.
That means you can bring your hear aids and hearing aid batteries along with you on board the plane and have a few spare batteries that you need for your hearing aids in your carry on luggage.
The TSA doesn't limit the amount of hearing aid batteries you can bring onto the plane so bring as many hearing aid batteries as you need to on the plane.
You can also bring spare batteries such as AA, AAA and laptop and cellphone batteries on board the plane.