Does a laptop temporarily use the battery to compensate for a weak power supply?

I ordered a laptop that has a 180W power supply.

Now I would like to buy a thunderbolt dock from Dell so that I only have to connect a single cable to the laptop itself. (180W dock)

However, I have read several times that the maximum power that can be transmitted over thunderbolt is 100W.

That brings us to the question. If the laptop needs 180w and the dock only supplies 100W, does the battery make up for the lack of power for a while?

If so, then of course only as long as the battery has enough charge. I'll say a medium length gaming session (I don't know)

Outside of gaming, I think 100w would be sufficient.

You can only charge up to 100W via TB. Dell laptops up to 130W.

If the laptop consumes more then the battery is used. In the long run, the battery will be empty.

Do you mean it pulls the missing power from the battery in parallel or does it switch over completely to the battery?

The question is whether you can still leave the original charging cable connected to the laptop when the thing is in the dock. That would be better for the battery. Because whenever the device needs more than the power supply delivers. Then it uses the battery. But since this is not constant, you sometimes have very short charge and discharge cycles, so-called microcycles. This is also what kills most of the batteries in smartphones and mobile navis.

The charger and battery are simply connected in parallel.
In order to be able to charge at all, the voltage of the charger must be slightly higher. This means that the electricity will only come from the charger for the time being.
A charger has an internal resistance. This means that the higher the current, the lower the voltage. If it falls below the current battery voltage, the battery supplies the current.

But there's a dynamic process that is leveling off. It can hardly be said who is currently supplying power for the laptop.