The best place is right where you store your hearing aid at night: in a bedside table drawer. That way the batteries will be there when you put your hearing aids in first thing in the morning. You may want to keep spare batteries with you in your hearing aid carrying case, too.
It’s not a good idea to keep batteries in the refrigerator. Condensation and moisture can harm them. Avoid extremes in temperature. Hearing aid batteries like room temperature, just like you.