As discussed by Rovelli and Vidotto in 2014  (Rovelli C., Vidotto F., Planck stars, Int. J. Mod. Phys. D, 23, 12, 1442026, (2014)), quantum-gravitational pressure can stop gravitational collapse and cause a bounce. A star collapsing gravitationally can be understood as an object which rapidly shrinks to the size where its energy density is planckian, then bounces back because of the quantum gravitational repulsion due to the quantum properties of space-time.

We can say a structure known as planck star exist at the center of black holes.

So basically i want to know  the difference between black hole remnants and Planck star.