Concussive Battery

You enchant a weapon to store concussive energy from your attacks. Melee weapon attacks made with this weapon deal an additional 1 point of force damage on a hit. Once per turn on a successful hit, you may add a d4 to a tally stored energy in the weapon. At any point during the spell's duration, you may spend an action to detonate the stored energy in your weapon as a shockwave. Every creature within 10 feet of you must make a Dexterity saving throw, taking damage equal to the number of d4 stored up in your weapon on a fail, taking half as much damage on a save.

At Higher Levels: When you cast this spell using a 3rd level spell slot, your attacks deal an additional 2 force damage and you may spend a reaction to detonate the spell upon losing concentration, dealing only half damage. When you cast this spell using a 4th level spell slot or higher, your attacks deal an additional 3 force damage and you may spend a reaction to detonate the spell upon losing concentration, without a damage penalty.