Charging state of the smartkey button cell

Hello dear people, I would like to know if I have the possibility to capture the condition of the button cell of the smartkey. My smartkey seems to be getting a bit sluggish. Must be quite close to the car. When I sat in the car yesterday, then also the steering wheel was not driven down immediately and the seat did not happen at first. Only after I had pressed the start button everything drove in its right place.