As previous answers have mentioned, this is not a hardware switch, but instead a software function. There is a kernel module available (tp-smapi-dkms), but it only works for Lenovo ThinkPads.
Enabling this function on your Dell laptop would require you or the vendor to write and implement a kernel module for your laptop model, the same way as they wrote the software for Windows.
Right now, your best bet is to unplug the battery manually when it's reached 80%. If you have some coding skills, you can use acpitool and notify-send to write an script to let you know when the battery has reached its 80%.
acpitool -B will display information about your battery, from where you can grep some information.
tl;dr: No, you cannot do it at this point, your vendor would need to write the software as it's not a hardware switch.