Finally, a normal explanation of how regenerative braking works 
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Hi, relatively new here but from what I can gather from reading this thread is regen breaking will already happen if the motor is told to stop itself and a battery is connected? I was actually planning on using a supercapacitor bank that gets trickle charged by a battery to absorb the energy and reuse it but please someone let me know if that’s a terrible idea
Yes, regen braking will happen if you are in FOC mode and you command a negative torque to stop the motor. It does not depend on having a battery connected, if you use a power supply you need to have some way to dissipate the energy to avoid voltage rise blowing up the power supply.
It’s not worth it to use a supercapacitor bank to absorb the regen energy, as you will either need huge capacitance or a complex high current circuit to manage charging / discharging the capacitor bank. It would be wiser to just buy a bigger / better lipo battery which has a higher maximum charge rate to safely absorb the regen energy.