Hey there Ts_1995,
To help with battery life on your AirPods, make sure you have the latest iOS version installed on your paired iPhone.
To update, go to Settings > General > Software Update.
If you're using the latest iOS, try resetting your AirPods to test if that helps with your battery life. To reset, follow these steps:
1. Put your AirPods in their charging case, and close the lid.
2. Wait 30 seconds.
3. Open the lid of your charging case.
4. On your iPhone, iPad, or iPod touch, go to Settings > Bluetooth and tap the More Info button next to your AirPods. (If you don't see your AirPods in Settings > Bluetooth, just go to the next step.)
5. Tap Forget This Device, and tap again to confirm.
6. With the lid open, press and hold the setup button on the back of the case for about 15 seconds, until the status light flashes amber, then white.*
7. Reconnect your AirPods: With your AirPods in their charging case and the lid open, place your AirPods close to your iPhone, iPad, or iPod touch. Follow the steps on your device's screen.
How to reset your AirPods and AirPods Pro - Apple Support
Should the behavior persist with your battery, Contact Apple Support for additional help.
Take care!