what is the chicago pd episdoe where hank voight stab someone through the palm

It’s “Actual Physical Violence” from Chicago P.D..

That’s the episode associated with Hank Voight being involved in the palm- stabbing moment you’re describing, and it’s listed as a 2015 episode.

Quick note

If you meant a different scene where Voight is stabbed or threatened in a similar way, Homecoming is another nearby episode people often confuse with violent Voight moments, but the palm-stab match is “Actual Physical Violence.”